diff --git a/roboimi/ddt/main.py b/roboimi/ddt/main.py
new file mode 100644
index 0000000..91ad9e9
--- /dev/null
+++ b/roboimi/ddt/main.py
@@ -0,0 +1,112 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+DDT 模型构建和优化器配置。
+"""
+import argparse
+from pathlib import Path
+
+import numpy as np
+import torch
+from .models import build_DDT_model
+
+
+def get_args_parser():
+    """获取 DDT 模型的参数解析器。"""
+    parser = argparse.ArgumentParser('DDT model configuration', add_help=False)
+    
+    # 学习率
+    parser.add_argument('--lr', default=1e-4, type=float)
+    parser.add_argument('--lr_backbone', default=1e-5, type=float)
+    parser.add_argument('--batch_size', default=2, type=int)
+    parser.add_argument('--weight_decay', default=1e-4, type=float)
+    parser.add_argument('--epochs', default=300, type=int)
+    parser.add_argument('--lr_drop', default=200, type=int)
+    parser.add_argument('--clip_max_norm', default=0.1, type=float,
+                        help='gradient clipping max norm')
+    parser.add_argument('--qpos_noise_std', action='store', default=0, type=float)
+
+    # Backbone 参数
+    parser.add_argument('--backbone', default='resnet18', type=str,
+                        help="Name of the convolutional backbone to use")
+    parser.add_argument('--dilation', action='store_true',
+                        help="If true, replace stride with dilation in the last conv block")
+    parser.add_argument('--position_embedding', default='sine', type=str, 
+                        choices=('sine', 'learned'),
+                        help="Type of positional embedding")
+    parser.add_argument('--camera_names', default=[], type=list,
+                        help="A list of camera names")
+
+    # Transformer 参数
+    parser.add_argument('--enc_layers', default=4, type=int,
+                        help="Number of encoding layers in the transformer")
+    parser.add_argument('--dec_layers', default=6, type=int,
+                        help="Number of decoding layers in the transformer")
+    parser.add_argument('--dim_feedforward', default=2048, type=int,
+                        help="Intermediate size of the feedforward layers")
+    parser.add_argument('--hidden_dim', default=512, type=int,
+                        help="Size of the embeddings (dimension of the transformer)")
+    parser.add_argument('--dropout', default=0.1, type=float,
+                        help="Dropout applied in the transformer")
+    parser.add_argument('--nheads', default=8, type=int,
+                        help="Number of attention heads")
+    parser.add_argument('--num_queries', default=100, type=int,
+                        help="Number of query slots (action horizon)")
+    parser.add_argument('--pre_norm', action='store_true')
+    parser.add_argument('--state_dim', default=14, type=int)
+    parser.add_argument('--action_dim', default=14, type=int)
+
+    # DDT 特有参数
+    parser.add_argument('--num_blocks', default=12, type=int,
+                        help="Total number of transformer blocks in DDT")
+    parser.add_argument('--mlp_ratio', default=4.0, type=float,
+                        help="MLP hidden dimension ratio")
+    parser.add_argument('--num_inference_steps', default=10, type=int,
+                        help="Number of diffusion inference steps")
+
+    # Segmentation (未使用)
+    parser.add_argument('--masks', action='store_true',
+                        help="Train segmentation head if provided")
+
+    return parser
+
+
+def build_DDT_model_and_optimizer(args_override):
+    """构建 DDT 模型和优化器。
+    
+    Args:
+        args_override: 覆盖默认参数的字典
+    
+    Returns:
+        model: DDT 模型
+        optimizer: AdamW 优化器
+    """
+    parser = argparse.ArgumentParser('DDT training script', parents=[get_args_parser()])
+    args = parser.parse_args([])  # 空列表避免命令行参数干扰
+
+    # 应用参数覆盖
+    for k, v in args_override.items():
+        setattr(args, k, v)
+
+    # 构建模型
+    model = build_DDT_model(args)
+    model.cuda()
+
+    # 配置优化器（backbone 使用较小学习率）
+    param_dicts = [
+        {
+            "params": [p for n, p in model.named_parameters() 
+                      if "backbone" not in n and p.requires_grad]
+        },
+        {
+            "params": [p for n, p in model.named_parameters() 
+                      if "backbone" in n and p.requires_grad],
+            "lr": args.lr_backbone,
+        },
+    ]
+    optimizer = torch.optim.AdamW(
+        param_dicts, 
+        lr=args.lr,
+        weight_decay=args.weight_decay
+    )
+
+    return model, optimizer
diff --git a/roboimi/ddt/models/__init__.py b/roboimi/ddt/models/__init__.py
new file mode 100644
index 0000000..fbc513e
--- /dev/null
+++ b/roboimi/ddt/models/__init__.py
@@ -0,0 +1,7 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+from .model import build as build_ddt
+from .model import build_ddt
+
+def build_DDT_model(args):
+    """构建 DDT 模型的统一入口。"""
+    return build_ddt(args)
diff --git a/roboimi/ddt/models/backbone.py b/roboimi/ddt/models/backbone.py
new file mode 100644
index 0000000..759bfb5
--- /dev/null
+++ b/roboimi/ddt/models/backbone.py
@@ -0,0 +1,168 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+Backbone modules.
+"""
+from collections import OrderedDict
+
+import torch
+import torch.nn.functional as F
+import torchvision
+from torch import nn
+from torchvision.models._utils import IntermediateLayerGetter
+from typing import Dict, List
+
+from util.misc import NestedTensor, is_main_process
+
+from .position_encoding import build_position_encoding
+
+class FrozenBatchNorm2d(torch.nn.Module):
+    """
+    BatchNorm2d where the batch statistics and the affine parameters are fixed.
+
+    Copy-paste from torchvision.misc.ops with added eps before rqsrt,
+    without which any other policy_models than torchvision.policy_models.resnet[18,34,50,101]
+    produce nans.
+    """
+
+    def __init__(self, n):
+        super(FrozenBatchNorm2d, self).__init__()
+        self.register_buffer("weight", torch.ones(n))
+        self.register_buffer("bias", torch.zeros(n))
+        self.register_buffer("running_mean", torch.zeros(n))
+        self.register_buffer("running_var", torch.ones(n))
+
+    def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict,
+                              missing_keys, unexpected_keys, error_msgs):
+        num_batches_tracked_key = prefix + 'num_batches_tracked'
+        if num_batches_tracked_key in state_dict:
+            del state_dict[num_batches_tracked_key]
+
+        super(FrozenBatchNorm2d, self)._load_from_state_dict(
+            state_dict, prefix, local_metadata, strict,
+            missing_keys, unexpected_keys, error_msgs)
+
+    def forward(self, x):
+        # move reshapes to the beginning
+        # to make it fuser-friendly
+        w = self.weight.reshape(1, -1, 1, 1)
+        b = self.bias.reshape(1, -1, 1, 1)
+        rv = self.running_var.reshape(1, -1, 1, 1)
+        rm = self.running_mean.reshape(1, -1, 1, 1)
+        eps = 1e-5
+        scale = w * (rv + eps).rsqrt()
+        bias = b - rm * scale
+        return x * scale + bias
+
+
+class BackboneBase(nn.Module):
+
+    def __init__(self, backbone: nn.Module, train_backbone: bool, num_channels: int, return_interm_layers: bool):
+        super().__init__()
+        # for name, parameter in backbone.named_parameters(): # only train later layers # TODO do we want this?
+        #     if not train_backbone or 'layer2' not in name and 'layer3' not in name and 'layer4' not in name:
+        #         parameter.requires_grad_(False)
+        if return_interm_layers:
+            return_layers = {"layer1": "0", "layer2": "1", "layer3": "2", "layer4": "3"}
+        else:
+            return_layers = {'layer4': "0"}
+        self.body = IntermediateLayerGetter(backbone, return_layers=return_layers)
+        self.num_channels = num_channels
+
+    def forward(self, tensor):
+        xs = self.body(tensor)
+        return xs
+        # out: Dict[str, NestedTensor] = {}
+        # for name, x in xs.items():
+        #     m = tensor_list.mask
+        #     assert m is not None
+        #     mask = F.interpolate(m[None].float(), size=x.shape[-2:]).to(torch.bool)[0]
+        #     out[name] = NestedTensor(x, mask)
+        # return out
+
+
+class Backbone(BackboneBase):
+    """ResNet backbone with frozen BatchNorm."""
+    def __init__(self, name: str,
+                 train_backbone: bool,
+                 return_interm_layers: bool,
+                 dilation: bool):
+        backbone = getattr(torchvision.models, name)(
+            replace_stride_with_dilation=[False, False, dilation],
+            pretrained=is_main_process(), norm_layer=FrozenBatchNorm2d) # pretrained # TODO do we want frozen batch_norm??
+        num_channels = 512 if name in ('resnet18', 'resnet34') else 2048
+        super().__init__(backbone, train_backbone, num_channels, return_interm_layers)
+
+
+# class DINOv2BackBone(nn.Module):
+#     def __init__(self) -> None:
+#         super().__init__()
+#         self.body = torch.hub.load('facebookresearch/dinov2', 'dinov2_vits14')
+#         self.body.eval()
+#         self.num_channels = 384
+    
+#     @torch.no_grad()
+#     def forward(self, tensor):
+#         xs = self.body.forward_features(tensor)["x_norm_patchtokens"]
+#         od = OrderedDict()
+#         od["0"] = xs.reshape(xs.shape[0], 22, 16, 384).permute(0, 3, 2, 1)
+#         return od
+
+class DINOv2BackBone(nn.Module):
+    def __init__(self, return_interm_layers: bool = False) -> None:
+        super().__init__()
+        self.body = torch.hub.load('facebookresearch/dinov2', 'dinov2_vits14')
+        self.body.eval()
+        self.num_channels = 384
+        self.return_interm_layers = return_interm_layers
+    
+    @torch.no_grad()
+    def forward(self, tensor):
+        features = self.body.forward_features(tensor)
+
+        if self.return_interm_layers:
+
+            layer1 = features["x_norm_patchtokens"]  
+            layer2 = features["x_norm_patchtokens"]  
+            layer3 = features["x_norm_patchtokens"]  
+            layer4 = features["x_norm_patchtokens"]  
+
+            od = OrderedDict()
+            od["0"] = layer1.reshape(layer1.shape[0], 22, 16, 384).permute(0, 3, 2, 1)
+            od["1"] = layer2.reshape(layer2.shape[0], 22, 16, 384).permute(0, 3, 2, 1)
+            od["2"] = layer3.reshape(layer3.shape[0], 22, 16, 384).permute(0, 3, 2, 1)
+            od["3"] = layer4.reshape(layer4.shape[0], 22, 16, 384).permute(0, 3, 2, 1)
+            return od
+        else:
+            xs = features["x_norm_patchtokens"]
+            od = OrderedDict()
+            od["0"] = xs.reshape(xs.shape[0], 22, 16, 384).permute(0, 3, 2, 1)
+            return od
+    
+class Joiner(nn.Sequential):
+    def __init__(self, backbone, position_embedding):
+        super().__init__(backbone, position_embedding)
+
+    def forward(self, tensor_list: NestedTensor):
+        xs = self[0](tensor_list)
+        out: List[NestedTensor] = []
+        pos = []
+        for name, x in xs.items():
+            out.append(x)
+            # position encoding
+            pos.append(self[1](x).to(x.dtype))
+
+        return out, pos
+
+
+def build_backbone(args):
+    position_embedding = build_position_encoding(args)
+    train_backbone = args.lr_backbone > 0
+    return_interm_layers = args.masks
+    if args.backbone == 'dino_v2':
+        backbone = DINOv2BackBone()
+    else:
+        assert args.backbone in ['resnet18', 'resnet34']
+        backbone = Backbone(args.backbone, train_backbone, return_interm_layers, args.dilation)
+    model = Joiner(backbone, position_embedding)
+    model.num_channels = backbone.num_channels
+    return model
diff --git a/roboimi/ddt/models/ddt.py b/roboimi/ddt/models/ddt.py
new file mode 100644
index 0000000..8efdd42
--- /dev/null
+++ b/roboimi/ddt/models/ddt.py
@@ -0,0 +1,631 @@
+"""
+动作序列扩散 Transformer (Action Decoupled Diffusion Transformer)
+
+基于 DDT 架构修改，用于生成机器人动作序列。
+主要改动:
+    1. 2D RoPE → 1D RoPE (适配时序数据)
+    2. LabelEmbedder → ObservationEncoder (观测条件)
+    3. 去除 patchify/unpatchify (动作序列已是 1D)
+"""
+
+import math
+from typing import Tuple, Optional
+
+import torch
+import torch.nn as nn
+from torch.nn.functional import scaled_dot_product_attention
+
+
+# ============================================================================
+# 通用工具函数
+# ============================================================================
+
+def modulate(x: torch.Tensor, shift: torch.Tensor, scale: torch.Tensor) -> torch.Tensor:
+    """AdaLN 调制函数。
+    
+    Args:
+        x: 输入张量。
+        shift: 偏移量。
+        scale: 缩放量。
+    
+    Returns:
+        调制后的张量: x * (1 + scale) + shift
+    """
+    return x * (1 + scale) + shift
+
+
+# ============================================================================
+# 1D 旋转位置编码 (RoPE)
+# ============================================================================
+
+def precompute_freqs_cis_1d(dim: int, seq_len: int, theta: float = 10000.0) -> torch.Tensor:
+    """预计算 1D 旋转位置编码的复数频率。
+    
+    用于时序数据（如动作序列）的位置编码，相比 2D RoPE 更简单高效。
+    
+    Args:
+        dim: 每个注意力头的维度 (head_dim)。
+        seq_len: 序列长度。
+        theta: RoPE 的基础频率，默认 10000.0。
+    
+    Returns:
+        复数频率张量，形状为 (seq_len, dim//2)。
+    """
+    # 计算频率: 1 / (theta^(2i/dim))
+    freqs = 1.0 / (theta ** (torch.arange(0, dim, 2).float() / dim))  # [dim//2]
+    # 位置索引
+    t = torch.arange(seq_len).float()  # [seq_len]
+    # 外积得到位置-频率矩阵
+    freqs = torch.outer(t, freqs)  # [seq_len, dim//2]
+    # 转换为复数形式 (极坐标)
+    freqs_cis = torch.polar(torch.ones_like(freqs), freqs)  # [seq_len, dim//2]
+    return freqs_cis
+
+
+def apply_rotary_emb_1d(
+        xq: torch.Tensor,
+        xk: torch.Tensor,
+        freqs_cis: torch.Tensor,
+) -> Tuple[torch.Tensor, torch.Tensor]:
+    """应用 1D 旋转位置编码到 Query 和 Key。
+    
+    Args:
+        xq: Query 张量，形状为 (B, N, H, Hc)。
+        xk: Key 张量，形状为 (B, N, H, Hc)。
+        freqs_cis: 预计算的复数频率，形状为 (N, Hc//2)。
+    
+    Returns:
+        应用 RoPE 后的 (xq, xk)，形状不变。
+    """
+    # 调整 freqs_cis 形状以便广播: [1, N, 1, Hc//2]
+    freqs_cis = freqs_cis[None, :, None, :]
+    
+    # 将实数张量视为复数: [B, N, H, Hc] -> [B, N, H, Hc//2] (复数)
+    xq_ = torch.view_as_complex(xq.float().reshape(*xq.shape[:-1], -1, 2))
+    xk_ = torch.view_as_complex(xk.float().reshape(*xk.shape[:-1], -1, 2))
+    
+    # 复数乘法实现旋转
+    xq_out = torch.view_as_real(xq_ * freqs_cis).flatten(3)  # [B, N, H, Hc]
+    xk_out = torch.view_as_real(xk_ * freqs_cis).flatten(3)
+    
+    return xq_out.type_as(xq), xk_out.type_as(xk)
+
+
+# ============================================================================
+# 基础组件
+# ============================================================================
+
+class Embed(nn.Module):
+    """线性嵌入层，将输入投影到隐藏空间。"""
+    
+    def __init__(
+            self,
+            in_chans: int = 3,
+            embed_dim: int = 768,
+            norm_layer: Optional[nn.Module] = None,
+            bias: bool = True,
+    ):
+        """初始化 Embed。
+        
+        Args:
+            in_chans: 输入通道数/维度。
+            embed_dim: 输出嵌入维度。
+            norm_layer: 可选的归一化层。
+            bias: 是否使用偏置。
+        """
+        super().__init__()
+        self.in_chans = in_chans
+        self.embed_dim = embed_dim
+        self.proj = nn.Linear(in_chans, embed_dim, bias=bias)
+        self.norm = norm_layer(embed_dim) if norm_layer else nn.Identity()
+    
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        x = self.proj(x)
+        x = self.norm(x)
+        return x
+
+
+class TimestepEmbedder(nn.Module):
+    """扩散时间步嵌入器。
+    
+    使用正弦位置编码 + MLP 将标量时间步映射到高维向量。
+    """
+    
+    def __init__(self, hidden_size: int, frequency_embedding_size: int = 256):
+        """初始化 TimestepEmbedder。
+        
+        Args:
+            hidden_size: 输出嵌入维度。
+            frequency_embedding_size: 正弦编码的维度。
+        """
+        super().__init__()
+        self.mlp = nn.Sequential(
+            nn.Linear(frequency_embedding_size, hidden_size, bias=True),
+            nn.SiLU(),
+            nn.Linear(hidden_size, hidden_size, bias=True),
+        )
+        self.frequency_embedding_size = frequency_embedding_size
+
+    @staticmethod
+    def timestep_embedding(t: torch.Tensor, dim: int, max_period: float = 10.0) -> torch.Tensor:
+        """生成正弦时间步嵌入。
+        
+        Args:
+            t: 时间步张量，形状为 (B,)。
+            dim: 嵌入维度。
+            max_period: 最大周期。
+        
+        Returns:
+            时间步嵌入，形状为 (B, dim)。
+        """
+        half = dim // 2
+        freqs = torch.exp(
+            -math.log(max_period) * torch.arange(start=0, end=half, dtype=torch.float32, device=t.device) / half
+        )
+        args = t[..., None].float() * freqs[None, ...]
+        embedding = torch.cat([torch.cos(args), torch.sin(args)], dim=-1)
+        if dim % 2:
+            embedding = torch.cat([embedding, torch.zeros_like(embedding[:, :1])], dim=-1)
+        return embedding
+
+    def forward(self, t: torch.Tensor) -> torch.Tensor:
+        t_freq = self.timestep_embedding(t, self.frequency_embedding_size)
+        t_emb = self.mlp(t_freq)
+        return t_emb
+
+
+class ObservationEncoder(nn.Module):
+    """观测状态编码器。
+    
+    将机器人的观测向量（如关节位置、末端位姿、图像特征等）
+    编码为条件向量，用于条件扩散生成。
+    
+    Attributes:
+        encoder: 两层 MLP 编码器。
+    
+    Example:
+        >>> encoder = ObservationEncoder(obs_dim=128, hidden_size=512)
+        >>> obs = torch.randn(2, 128)
+        >>> cond = encoder(obs)  # [2, 512]
+    """
+    
+    def __init__(self, obs_dim: int, hidden_size: int):
+        """初始化 ObservationEncoder。
+        
+        Args:
+            obs_dim: 观测向量的维度。
+            hidden_size: 输出条件向量的维度。
+        """
+        super().__init__()
+        self.encoder = nn.Sequential(
+            nn.Linear(obs_dim, hidden_size),
+            nn.SiLU(),
+            nn.Linear(hidden_size, hidden_size),
+        )
+    
+    def forward(self, obs: torch.Tensor) -> torch.Tensor:
+        """前向传播。
+        
+        Args:
+            obs: 观测向量，形状为 (B, obs_dim)。
+        
+        Returns:
+            条件向量，形状为 (B, hidden_size)。
+        """
+        return self.encoder(obs)
+
+
+class FinalLayer(nn.Module):
+    """最终输出层，使用 AdaLN 调制后输出预测结果。"""
+    
+    def __init__(self, hidden_size: int, out_channels: int):
+        """初始化 FinalLayer。
+        
+        Args:
+            hidden_size: 输入隐藏维度。
+            out_channels: 输出通道数/维度。
+        """
+        super().__init__()
+        self.norm_final = nn.LayerNorm(hidden_size, elementwise_affine=False, eps=1e-6)
+        self.linear = nn.Linear(hidden_size, out_channels, bias=True)
+        self.adaLN_modulation = nn.Sequential(
+            nn.Linear(hidden_size, 2 * hidden_size, bias=True)
+        )
+
+    def forward(self, x: torch.Tensor, c: torch.Tensor) -> torch.Tensor:
+        """前向传播。
+        
+        Args:
+            x: 输入张量，形状为 (B, N, hidden_size)。
+            c: 条件张量，形状为 (B, N, hidden_size) 或 (B, 1, hidden_size)。
+        
+        Returns:
+            输出张量，形状为 (B, N, out_channels)。
+        """
+        shift, scale = self.adaLN_modulation(c).chunk(2, dim=-1)
+        x = modulate(self.norm_final(x), shift, scale)
+        x = self.linear(x)
+        return x
+
+
+# ============================================================================
+# 归一化和前馈网络
+# ============================================================================
+
+class RMSNorm(nn.Module):
+    """Root Mean Square Layer Normalization (RMS 归一化层)。
+    
+    RMSNorm 是 LayerNorm 的简化版本，去掉了均值中心化操作，只保留缩放。
+    相比 LayerNorm 计算更快，效果相当，被广泛用于 LLaMA、Mistral 等大模型。
+    
+    数学公式:
+        RMSNorm(x) = x / sqrt(mean(x^2) + eps) * weight
+    """
+    
+    def __init__(self, hidden_size: int, eps: float = 1e-6):
+        """初始化 RMSNorm。
+        
+        Args:
+            hidden_size: 输入特征的维度。
+            eps: 防止除零的小常数。
+        """
+        super().__init__()
+        self.weight = nn.Parameter(torch.ones(hidden_size))
+        self.variance_epsilon = eps
+
+    def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
+        input_dtype = hidden_states.dtype
+        hidden_states = hidden_states.to(torch.float32)
+        variance = hidden_states.pow(2).mean(-1, keepdim=True)
+        hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon)
+        return self.weight * hidden_states.to(input_dtype)
+
+
+class FeedForward(nn.Module):
+    """SwiGLU 前馈网络 (Feed-Forward Network)。
+    
+    使用 SwiGLU 门控激活函数的前馈网络，来自 LLaMA 架构。
+    
+    结构:
+        output = W2(SiLU(W1(x)) * W3(x))
+    """
+    
+    def __init__(self, dim: int, hidden_dim: int):
+        """初始化 FeedForward。
+        
+        Args:
+            dim: 输入和输出的特征维度。
+            hidden_dim: 隐藏层维度（实际使用 2/3 * hidden_dim）。
+        """
+        super().__init__()
+        hidden_dim = int(2 * hidden_dim / 3)
+        self.w1 = nn.Linear(dim, hidden_dim, bias=False)
+        self.w3 = nn.Linear(dim, hidden_dim, bias=False)
+        self.w2 = nn.Linear(hidden_dim, dim, bias=False)
+    
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        x = self.w2(torch.nn.functional.silu(self.w1(x)) * self.w3(x))
+        return x
+
+
+# ============================================================================
+# 注意力机制
+# ============================================================================
+
+class RAttention(nn.Module):
+    """带有旋转位置编码的多头自注意力 (Rotary Attention)。
+    
+    集成了以下技术:
+        - 1D RoPE: 通过复数旋转编码时序位置信息
+        - QK-Norm: 对 Query 和 Key 进行归一化，稳定训练
+        - Flash Attention: 使用 scaled_dot_product_attention
+    """
+    
+    def __init__(
+            self,
+            dim: int,
+            num_heads: int = 8,
+            qkv_bias: bool = False,
+            qk_norm: bool = True,
+            attn_drop: float = 0.,
+            proj_drop: float = 0.,
+            norm_layer: nn.Module = RMSNorm,
+    ) -> None:
+        """初始化 RAttention。
+        
+        Args:
+            dim: 输入特征维度，必须能被 num_heads 整除。
+            num_heads: 注意力头数。
+            qkv_bias: QKV 投影是否使用偏置。
+            qk_norm: 是否对 Q, K 进行归一化。
+            attn_drop: 注意力权重的 dropout 率。
+            proj_drop: 输出投影的 dropout 率。
+            norm_layer: 归一化层类型。
+        """
+        super().__init__()
+        assert dim % num_heads == 0, 'dim should be divisible by num_heads'
+
+        self.dim = dim
+        self.num_heads = num_heads
+        self.head_dim = dim // num_heads
+        self.scale = self.head_dim ** -0.5
+
+        self.qkv = nn.Linear(dim, dim * 3, bias=qkv_bias)
+        self.q_norm = norm_layer(self.head_dim) if qk_norm else nn.Identity()
+        self.k_norm = norm_layer(self.head_dim) if qk_norm else nn.Identity()
+        self.attn_drop = nn.Dropout(attn_drop)
+        self.proj = nn.Linear(dim, dim)
+        self.proj_drop = nn.Dropout(proj_drop)
+
+    def forward(
+            self,
+            x: torch.Tensor,
+            pos: torch.Tensor,
+            mask: Optional[torch.Tensor] = None
+    ) -> torch.Tensor:
+        """前向传播。
+        
+        Args:
+            x: 输入张量，形状为 (B, N, C)。
+            pos: 1D RoPE 位置编码，形状为 (N, head_dim//2)。
+            mask: 可选的注意力掩码。
+        
+        Returns:
+            输出张量，形状为 (B, N, C)。
+        """
+        B, N, C = x.shape
+        
+        # QKV 投影
+        qkv = self.qkv(x).reshape(B, N, 3, self.num_heads, C // self.num_heads).permute(2, 0, 1, 3, 4)
+        q, k, v = qkv[0], qkv[1], qkv[2]  # [B, N, H, Hc]
+        
+        # QK-Norm
+        q = self.q_norm(q)
+        k = self.k_norm(k)
+        
+        # 应用 1D RoPE
+        q, k = apply_rotary_emb_1d(q, k, freqs_cis=pos)
+        
+        # 调整维度: [B, N, H, Hc] -> [B, H, N, Hc]
+        q = q.view(B, -1, self.num_heads, C // self.num_heads).transpose(1, 2)
+        k = k.view(B, -1, self.num_heads, C // self.num_heads).transpose(1, 2).contiguous()
+        v = v.view(B, -1, self.num_heads, C // self.num_heads).transpose(1, 2).contiguous()
+
+        # Scaled Dot-Product Attention
+        x = scaled_dot_product_attention(q, k, v, attn_mask=mask, dropout_p=0.0)
+
+        # 输出投影
+        x = x.transpose(1, 2).reshape(B, N, C)
+        x = self.proj(x)
+        x = self.proj_drop(x)
+        return x
+
+
+# ============================================================================
+# Transformer Block
+# ============================================================================
+
+class ActionDDTBlock(nn.Module):
+    """动作 DDT Transformer Block。
+    
+    结构: Pre-Norm + AdaLN + Attention + FFN
+    """
+    
+    def __init__(self, hidden_size: int, num_heads: int, mlp_ratio: float = 4.0):
+        """初始化 ActionDDTBlock。
+        
+        Args:
+            hidden_size: 隐藏层维度。
+            num_heads: 注意力头数。
+            mlp_ratio: FFN 隐藏层倍率。
+        """
+        super().__init__()
+        self.norm1 = RMSNorm(hidden_size, eps=1e-6)
+        self.attn = RAttention(hidden_size, num_heads=num_heads, qkv_bias=False)
+        self.norm2 = RMSNorm(hidden_size, eps=1e-6)
+        mlp_hidden_dim = int(hidden_size * mlp_ratio)
+        self.mlp = FeedForward(hidden_size, mlp_hidden_dim)
+        self.adaLN_modulation = nn.Sequential(
+            nn.Linear(hidden_size, 6 * hidden_size, bias=True)
+        )
+
+    def forward(
+            self,
+            x: torch.Tensor,
+            c: torch.Tensor,
+            pos: torch.Tensor,
+            mask: Optional[torch.Tensor] = None
+    ) -> torch.Tensor:
+        """前向传播。
+        
+        Args:
+            x: 输入张量，形状为 (B, N, hidden_size)。
+            c: 条件张量，形状为 (B, 1, hidden_size) 或 (B, N, hidden_size)。
+            pos: 位置编码。
+            mask: 可选的注意力掩码。
+        
+        Returns:
+            输出张量，形状为 (B, N, hidden_size)。
+        """
+        # AdaLN 调制参数
+        shift_msa, scale_msa, gate_msa, shift_mlp, scale_mlp, gate_mlp = \
+            self.adaLN_modulation(c).chunk(6, dim=-1)
+        
+        # Attention 分支
+        x = x + gate_msa * self.attn(modulate(self.norm1(x), shift_msa, scale_msa), pos, mask=mask)
+        # FFN 分支
+        x = x + gate_mlp * self.mlp(modulate(self.norm2(x), shift_mlp, scale_mlp))
+        
+        return x
+
+
+# ============================================================================
+# 主模型: ActionDDT
+# ============================================================================
+
+class ActionDDT(nn.Module):
+    """动作序列解耦扩散 Transformer (Action Decoupled Diffusion Transformer)。
+    
+    基于 DDT 架构，专为机器人动作序列生成设计。
+    将模型解耦为编码器和解码器两部分，编码器状态可缓存以加速推理。
+    
+    架构:
+        - 编码器: 前 num_encoder_blocks 个 block，生成状态 s
+        - 解码器: 剩余 block，使用状态 s 对动作序列 x 去噪
+        - 使用 1D RoPE 进行时序位置编码
+        - 使用 AdaLN 注入时间步和观测条件
+    
+    Args:
+        action_dim: 动作向量维度（如 7-DoF 机械臂为 7）。
+        obs_dim: 观测向量维度。
+        action_horizon: 预测的动作序列长度。
+        hidden_size: Transformer 隐藏层维度。
+        num_blocks: Transformer block 总数。
+        num_encoder_blocks: 编码器 block 数量。
+        num_heads: 注意力头数。
+        mlp_ratio: FFN 隐藏层倍率。
+    
+    输入:
+        x (Tensor): 带噪声的动作序列，形状为 (B, T, action_dim)。
+        t (Tensor): 扩散时间步，形状为 (B,)，取值范围 [0, 1]。
+        obs (Tensor): 观测条件，形状为 (B, obs_dim)。
+        s (Tensor, optional): 缓存的编码器状态。
+    
+    输出:
+        x (Tensor): 预测的速度场/噪声，形状为 (B, T, action_dim)。
+        s (Tensor): 编码器状态，可缓存复用。
+    
+    Example:
+        >>> model = ActionDDT(action_dim=7, obs_dim=128, action_horizon=16)
+        >>> x = torch.randn(2, 16, 7)   # 带噪声的动作序列
+        >>> t = torch.rand(2)            # 随机时间步
+        >>> obs = torch.randn(2, 128)    # 观测条件
+        >>> out, state = model(x, t, obs)
+        >>> out.shape
+        torch.Size([2, 16, 7])
+    """
+    
+    def __init__(
+            self,
+            action_dim: int = 7,
+            obs_dim: int = 128,
+            action_horizon: int = 16,
+            hidden_size: int = 512,
+            num_blocks: int = 12,
+            num_encoder_blocks: int = 4,
+            num_heads: int = 8,
+            mlp_ratio: float = 4.0,
+    ):
+        super().__init__()
+        
+        # 保存配置
+        self.action_dim = action_dim
+        self.obs_dim = obs_dim
+        self.action_horizon = action_horizon
+        self.hidden_size = hidden_size
+        self.num_blocks = num_blocks
+        self.num_encoder_blocks = num_encoder_blocks
+        self.num_heads = num_heads
+        
+        # 动作嵌入层
+        self.x_embedder = Embed(action_dim, hidden_size, bias=True)
+        self.s_embedder = Embed(action_dim, hidden_size, bias=True)
+        
+        # 条件嵌入
+        self.t_embedder = TimestepEmbedder(hidden_size)
+        self.obs_encoder = ObservationEncoder(obs_dim, hidden_size)
+        
+        # 输出层
+        self.final_layer = FinalLayer(hidden_size, action_dim)
+        
+        # Transformer blocks
+        self.blocks = nn.ModuleList([
+            ActionDDTBlock(hidden_size, num_heads, mlp_ratio)
+            for _ in range(num_blocks)
+        ])
+        
+        # 预计算 1D 位置编码
+        pos = precompute_freqs_cis_1d(hidden_size // num_heads, action_horizon)
+        self.register_buffer('pos', pos)
+        
+        # 初始化权重
+        self.initialize_weights()
+    
+    def initialize_weights(self):
+        """初始化模型权重。"""
+        # 嵌入层使用 Xavier 初始化
+        for embedder in [self.x_embedder, self.s_embedder]:
+            w = embedder.proj.weight.data
+            nn.init.xavier_uniform_(w.view([w.shape[0], -1]))
+            nn.init.constant_(embedder.proj.bias, 0)
+        
+        # 时间步嵌入 MLP
+        nn.init.normal_(self.t_embedder.mlp[0].weight, std=0.02)
+        nn.init.normal_(self.t_embedder.mlp[2].weight, std=0.02)
+        
+        # 观测编码器
+        for m in self.obs_encoder.encoder:
+            if isinstance(m, nn.Linear):
+                nn.init.normal_(m.weight, std=0.02)
+                if m.bias is not None:
+                    nn.init.constant_(m.bias, 0)
+        
+        # 输出层零初始化 (AdaLN-Zero)
+        nn.init.constant_(self.final_layer.adaLN_modulation[-1].weight, 0)
+        nn.init.constant_(self.final_layer.adaLN_modulation[-1].bias, 0)
+        nn.init.constant_(self.final_layer.linear.weight, 0)
+        nn.init.constant_(self.final_layer.linear.bias, 0)
+    
+    def forward(
+            self,
+            x: torch.Tensor,
+            t: torch.Tensor,
+            obs: torch.Tensor,
+            s: Optional[torch.Tensor] = None,
+            mask: Optional[torch.Tensor] = None,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        """前向传播。
+        
+        Args:
+            x: 带噪声的动作序列 [B, T, action_dim]
+            t: 扩散时间步 [B] 或 [B, 1]，取值范围 [0, 1]
+            obs: 观测条件 [B, obs_dim]
+            s: 可选的编码器状态缓存 [B, T, hidden_size]
+            mask: 可选的注意力掩码
+        
+        Returns:
+            x: 预测的速度场/噪声 [B, T, action_dim]
+            s: 编码器状态 [B, T, hidden_size]，可缓存复用
+        """
+        B, T, _ = x.shape
+        
+        # 1. 时间步嵌入: [B] -> [B, 1, hidden_size]
+        t_emb = self.t_embedder(t.view(-1)).view(B, 1, self.hidden_size)
+        
+        # 2. 观测条件嵌入: [B, obs_dim] -> [B, 1, hidden_size]
+        obs_emb = self.obs_encoder(obs).view(B, 1, self.hidden_size)
+        
+        # 3. 融合条件: c = SiLU(t + obs)
+        c = nn.functional.silu(t_emb + obs_emb)
+        
+        # 4. 编码器部分: 生成状态 s
+        if s is None:
+            # 状态嵌入: [B, T, action_dim] -> [B, T, hidden_size]
+            s = self.s_embedder(x)
+            # 通过编码器 blocks
+            for i in range(self.num_encoder_blocks):
+                s = self.blocks[i](s, c, self.pos, mask)
+            # 融合时间信息
+            s = nn.functional.silu(t_emb + s)
+        
+        # 5. 解码器部分: 去噪
+        # 输入嵌入: [B, T, action_dim] -> [B, T, hidden_size]
+        x = self.x_embedder(x)
+        # 通过解码器 blocks，以 s 作为条件
+        for i in range(self.num_encoder_blocks, self.num_blocks):
+            x = self.blocks[i](x, s, self.pos, None)
+        
+        # 6. 最终层: [B, T, hidden_size] -> [B, T, action_dim]
+        x = self.final_layer(x, s)
+        
+        return x, s
\ No newline at end of file
diff --git a/roboimi/ddt/models/model.py b/roboimi/ddt/models/model.py
new file mode 100644
index 0000000..5176c38
--- /dev/null
+++ b/roboimi/ddt/models/model.py
@@ -0,0 +1,304 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+DDT model and criterion classes.
+
+核心组装文件，将 Backbone、Transformer、Diffusion 组件组装为完整模型。
+"""
+import torch
+import torch.nn.functional as F
+from torch import nn
+import numpy as np
+
+from .backbone import build_backbone
+
+
+class SpatialSoftmax(nn.Module):
+    """Spatial Softmax 层，将特征图转换为关键点坐标。
+    
+    来自 Diffusion Policy，保留空间位置信息。
+    对每个通道计算软注意力加权的期望坐标。
+    
+    Args:
+        num_kp: 关键点数量（等于输入通道数）
+        temperature: Softmax 温度参数（可学习）
+        learnable_temperature: 是否学习温度参数
+    
+    输入: [B, C, H, W]
+    输出: [B, C * 2] - 每个通道输出 (x, y) 坐标
+    """
+    
+    def __init__(self, num_kp: int = None, temperature: float = 1.0, learnable_temperature: bool = True):
+        super().__init__()
+        self.num_kp = num_kp
+        if learnable_temperature:
+            self.temperature = nn.Parameter(torch.ones(1) * temperature)
+        else:
+            self.register_buffer('temperature', torch.ones(1) * temperature)
+    
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        B, C, H, W = x.shape
+        
+        # 生成归一化坐标网格 [-1, 1]
+        pos_x = torch.linspace(-1, 1, W, device=x.device, dtype=x.dtype)
+        pos_y = torch.linspace(-1, 1, H, device=x.device, dtype=x.dtype)
+        
+        # 展平空间维度
+        x_flat = x.view(B, C, -1)  # [B, C, H*W]
+        
+        # Softmax 得到注意力权重
+        attention = F.softmax(x_flat / self.temperature, dim=-1)  # [B, C, H*W]
+        
+        # 计算期望坐标
+        # pos_x: [W] -> [1, 1, W] -> repeat -> [1, 1, H*W]
+        pos_x_grid = pos_x.view(1, 1, 1, W).expand(1, 1, H, W).reshape(1, 1, -1)
+        pos_y_grid = pos_y.view(1, 1, H, 1).expand(1, 1, H, W).reshape(1, 1, -1)
+        
+        # 加权求和得到期望坐标
+        expected_x = (attention * pos_x_grid).sum(dim=-1)  # [B, C]
+        expected_y = (attention * pos_y_grid).sum(dim=-1)  # [B, C]
+        
+        # 拼接 x, y 坐标
+        keypoints = torch.cat([expected_x, expected_y], dim=-1)  # [B, C * 2]
+        
+        return keypoints
+
+from .ddt import ActionDDT
+
+
+def get_sinusoid_encoding_table(n_position, d_hid):
+    """生成正弦位置编码表。"""
+    def get_position_angle_vec(position):
+        return [position / np.power(10000, 2 * (hid_j // 2) / d_hid) for hid_j in range(d_hid)]
+
+    sinusoid_table = np.array([get_position_angle_vec(pos_i) for pos_i in range(n_position)])
+    sinusoid_table[:, 0::2] = np.sin(sinusoid_table[:, 0::2])  # dim 2i
+    sinusoid_table[:, 1::2] = np.cos(sinusoid_table[:, 1::2])  # dim 2i+1
+
+    return torch.FloatTensor(sinusoid_table).unsqueeze(0)
+
+
+class DDT(nn.Module):
+    """DDT (Decoupled Diffusion Transformer) 模型。
+    
+    将视觉 Backbone 和 ActionDDT 扩散模型组合，实现基于图像观测的动作序列生成。
+    
+    架构:
+        1. Backbone: 提取多相机图像特征
+        2. 特征投影: 将图像特征投影到隐藏空间 (Bottleneck 降维)
+        3. 状态编码: 编码机器人关节状态
+        4. ActionDDT: 扩散 Transformer 生成动作序列
+    
+    Args:
+        backbones: 视觉骨干网络列表（每个相机一个）
+        state_dim: 机器人状态维度
+        action_dim: 动作维度
+        num_queries: 预测的动作序列长度
+        camera_names: 相机名称列表
+        hidden_dim: Transformer 隐藏维度
+        num_blocks: Transformer block 数量
+        num_encoder_blocks: 编码器 block 数量
+        num_heads: 注意力头数
+        num_kp: Spatial Softmax 的关键点数量 (默认 32)
+    """
+    
+    def __init__(
+        self,
+        backbones,
+        state_dim: int,
+        action_dim: int,
+        num_queries: int,
+        camera_names: list,
+        hidden_dim: int = 512,
+        num_blocks: int = 12,
+        num_encoder_blocks: int = 4,
+        num_heads: int = 8,
+        mlp_ratio: float = 4.0,
+        num_kp: int = 32, # [修改] 新增参数，默认 32
+    ):
+        super().__init__()
+        
+        self.num_queries = num_queries
+        self.camera_names = camera_names
+        self.hidden_dim = hidden_dim
+        self.state_dim = state_dim
+        self.action_dim = action_dim
+        self.num_kp = num_kp
+        
+        # Backbone 相关
+        self.backbones = nn.ModuleList(backbones)
+        
+        # [修改] 投影层: ResNet Channels -> num_kp (32)
+        # 这是一个 Bottleneck 层，大幅减少特征通道数
+        self.input_proj = nn.Conv2d(
+            backbones[0].num_channels, num_kp, kernel_size=1
+        )
+        
+        # 状态编码 (2层 MLP，与 Diffusion Policy 一致)
+        # 状态依然映射到 hidden_dim (512)，保持信息量
+        self.input_proj_robot_state = nn.Sequential(
+            nn.Linear(state_dim, hidden_dim),
+            nn.ReLU(),
+            nn.Linear(hidden_dim, hidden_dim),
+        )
+        
+        # [修改] 图像特征聚合 (SpatialSoftmax)
+        # 输入: [B, num_kp, H, W]
+        # 输出: [B, num_kp * 2] (每个通道的 x, y 坐标)
+        self.img_feature_proj = SpatialSoftmax(num_kp=num_kp)
+        
+        # [修改] 计算观测维度: 图像特征 + 状态
+        # 图像部分: 关键点数量 * 2(x,y) * 摄像头数量
+        img_feature_dim = num_kp * 2 * len(camera_names)
+        obs_dim = img_feature_dim + hidden_dim
+        
+        # ActionDDT 扩散模型
+        self.action_ddt = ActionDDT(
+            action_dim=action_dim,
+            obs_dim=obs_dim, # 使用新的、更紧凑的维度
+            action_horizon=num_queries,
+            hidden_size=hidden_dim,
+            num_blocks=num_blocks,
+            num_encoder_blocks=num_encoder_blocks,
+            num_heads=num_heads,
+            mlp_ratio=mlp_ratio,
+        )
+    
+    def encode_observations(self, qpos, image):
+        """编码观测（图像 + 状态）为条件向量。
+        
+        Args:
+            qpos: 机器人关节状态 [B, state_dim]
+            image: 多相机图像 [B, num_cam, C, H, W]
+        
+        Returns:
+            obs: 观测条件向量 [B, obs_dim]
+        """
+        bs = qpos.shape[0]
+        
+        # 编码图像特征
+        all_cam_features = []
+        for cam_id, cam_name in enumerate(self.camera_names):
+            features, pos = self.backbones[cam_id](image[:, cam_id])
+            features = features[0]  # 取最后一层特征
+            
+            # [说明] 这里的 input_proj 现在会将通道压缩到 32
+            features = self.input_proj(features)  # [B, num_kp, H', W']
+            
+            # [说明] SpatialSoftmax 提取 32 个关键点坐标
+            features = self.img_feature_proj(features)  # [B, num_kp * 2]
+            
+            all_cam_features.append(features)
+        
+        # 拼接所有相机特征
+        img_features = torch.cat(all_cam_features, dim=-1)  # [B, num_kp * 2 * num_cam]
+        
+        # 编码状态
+        qpos_features = self.input_proj_robot_state(qpos)  # [B, hidden_dim]
+        
+        # 拼接观测
+        obs = torch.cat([img_features, qpos_features], dim=-1)  # [B, obs_dim]
+        
+        return obs
+    
+    def forward(
+        self,
+        qpos,
+        image,
+        env_state,
+        actions=None,
+        is_pad=None,
+        timesteps=None,
+    ):
+        """前向传播。
+        
+        训练时:
+            输入带噪声的动作序列和时间步，预测噪声/速度场
+        推理时:
+            通过扩散采样生成动作序列
+        
+        Args:
+            qpos: 机器人关节状态 [B, state_dim]
+            image: 多相机图像 [B, num_cam, C, H, W]
+            env_state: 环境状态（未使用）
+            actions: 动作序列 [B, T, action_dim]（训练时为带噪声动作）
+            is_pad: padding 标记 [B, T]（未使用）
+            timesteps: 扩散时间步 [B]（训练时提供）
+        
+        Returns:
+            训练时: (noise_pred, encoder_state)
+            推理时: (action_pred, encoder_state)
+        """
+        # 1. 编码观测
+        obs = self.encode_observations(qpos, image)
+        
+        # 2. 扩散模型前向
+        if actions is not None and timesteps is not None:
+            # 训练模式: 预测噪声
+            noise_pred, encoder_state = self.action_ddt(
+                x=actions,
+                t=timesteps,
+                obs=obs,
+            )
+            return noise_pred, encoder_state
+        else:
+            # 推理模式: 需要在 Policy 层进行扩散采样
+            # 这里返回编码的观测，供 Policy 层使用
+            return obs, None
+    
+    def get_obs_dim(self):
+        """返回观测向量的维度。"""
+        # [修改] 使用 num_kp 重新计算
+        return self.num_kp * 2 * len(self.camera_names) + self.hidden_dim
+
+
+def build(args):
+    """构建 DDT 模型。
+    
+    Args:
+        args: 包含模型配置的参数对象
+            - state_dim: 状态维度
+            - action_dim: 动作维度
+            - camera_names: 相机名称列表
+            - hidden_dim: 隐藏维度
+            - num_queries: 动作序列长度
+            - num_blocks: Transformer block 数量
+            - enc_layers: 编码器层数
+            - nheads: 注意力头数
+            - num_kp: 关键点数量 (可选，默认32)
+    
+    Returns:
+        model: DDT 模型实例
+    """
+    state_dim = args.state_dim
+    action_dim = args.action_dim
+    
+    # 构建 Backbone（每个相机一个）
+    backbones = []
+    for _ in args.camera_names:
+        backbone = build_backbone(args)
+        backbones.append(backbone)
+    
+    # 构建 DDT 模型
+    model = DDT(
+        backbones=backbones,
+        state_dim=state_dim,
+        action_dim=action_dim,
+        num_queries=args.num_queries,
+        camera_names=args.camera_names,
+        hidden_dim=args.hidden_dim,
+        num_blocks=getattr(args, 'num_blocks', 12),
+        num_encoder_blocks=getattr(args, 'enc_layers', 4),
+        num_heads=args.nheads,
+        mlp_ratio=getattr(args, 'mlp_ratio', 4.0),
+        num_kp=getattr(args, 'num_kp', 32), # [修改] 传递 num_kp 参数
+    )
+    
+    n_parameters = sum(p.numel() for p in model.parameters() if p.requires_grad)
+    print("number of parameters: %.2fM" % (n_parameters / 1e6,))
+    
+    return model
+
+
+def build_ddt(args):
+    """build 的别名，保持接口一致性。"""
+    return build(args)
\ No newline at end of file
diff --git a/roboimi/ddt/models/position_encoding.py b/roboimi/ddt/models/position_encoding.py
new file mode 100644
index 0000000..c75733e
--- /dev/null
+++ b/roboimi/ddt/models/position_encoding.py
@@ -0,0 +1,91 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+Various positional encodings for the transformer.
+"""
+import math
+import torch
+from torch import nn
+
+from util.misc import NestedTensor
+
+
+class PositionEmbeddingSine(nn.Module):
+    """
+    This is a more standard version of the position embedding, very similar to the one
+    used by the Attention is all you need paper, generalized to work on images.
+    """
+    def __init__(self, num_pos_feats=64, temperature=10000, normalize=False, scale=None):
+        super().__init__()
+        self.num_pos_feats = num_pos_feats
+        self.temperature = temperature
+        self.normalize = normalize
+        if scale is not None and normalize is False:
+            raise ValueError("normalize should be True if scale is passed")
+        if scale is None:
+            scale = 2 * math.pi
+        self.scale = scale
+
+    def forward(self, tensor):
+        x = tensor
+        # mask = tensor_list.mask
+        # assert mask is not None
+        # not_mask = ~mask
+
+        not_mask = torch.ones_like(x[0, [0]])
+        y_embed = not_mask.cumsum(1, dtype=torch.float32)
+        x_embed = not_mask.cumsum(2, dtype=torch.float32)
+        if self.normalize:
+            eps = 1e-6
+            y_embed = y_embed / (y_embed[:, -1:, :] + eps) * self.scale
+            x_embed = x_embed / (x_embed[:, :, -1:] + eps) * self.scale
+
+        dim_t = torch.arange(self.num_pos_feats, dtype=torch.float32, device=x.device)
+        dim_t = self.temperature ** (2 * (dim_t // 2) / self.num_pos_feats)
+
+        pos_x = x_embed[:, :, :, None] / dim_t
+        pos_y = y_embed[:, :, :, None] / dim_t
+        pos_x = torch.stack((pos_x[:, :, :, 0::2].sin(), pos_x[:, :, :, 1::2].cos()), dim=4).flatten(3)
+        pos_y = torch.stack((pos_y[:, :, :, 0::2].sin(), pos_y[:, :, :, 1::2].cos()), dim=4).flatten(3)
+        pos = torch.cat((pos_y, pos_x), dim=3).permute(0, 3, 1, 2)
+        return pos
+
+
+class PositionEmbeddingLearned(nn.Module):
+    """
+    Absolute pos embedding, learned.
+    """
+    def __init__(self, num_pos_feats=256):
+        super().__init__()
+        self.row_embed = nn.Embedding(50, num_pos_feats)
+        self.col_embed = nn.Embedding(50, num_pos_feats)
+        self.reset_parameters()
+
+    def reset_parameters(self):
+        nn.init.uniform_(self.row_embed.weight)
+        nn.init.uniform_(self.col_embed.weight)
+
+    def forward(self, tensor_list: NestedTensor):
+        x = tensor_list.tensors
+        h, w = x.shape[-2:]
+        i = torch.arange(w, device=x.device)
+        j = torch.arange(h, device=x.device)
+        x_emb = self.col_embed(i)
+        y_emb = self.row_embed(j)
+        pos = torch.cat([
+            x_emb.unsqueeze(0).repeat(h, 1, 1),
+            y_emb.unsqueeze(1).repeat(1, w, 1),
+        ], dim=-1).permute(2, 0, 1).unsqueeze(0).repeat(x.shape[0], 1, 1, 1)
+        return pos
+
+
+def build_position_encoding(args):
+    N_steps = args.hidden_dim // 2
+    if args.position_embedding in ('v2', 'sine'):
+        # TODO find a better way of exposing other arguments
+        position_embedding = PositionEmbeddingSine(N_steps, normalize=True)
+    elif args.position_embedding in ('v3', 'learned'):
+        position_embedding = PositionEmbeddingLearned(N_steps)
+    else:
+        raise ValueError(f"not supported {args.position_embedding}")
+
+    return position_embedding
diff --git a/roboimi/ddt/models/transformer.py b/roboimi/ddt/models/transformer.py
new file mode 100644
index 0000000..2306ab2
--- /dev/null
+++ b/roboimi/ddt/models/transformer.py
@@ -0,0 +1,312 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+DETR Transformer class.
+
+Copy-paste from torch.nn.Transformer with modifications:
+    * positional encodings are passed in MHattention
+    * extra LN at the end of encoder is removed
+    * decoder returns a stack of activations from all decoding layers
+"""
+import copy
+from typing import Optional, List
+
+import torch
+import torch.nn.functional as F
+from torch import nn, Tensor
+
+
+class Transformer(nn.Module):
+
+    def __init__(self, d_model=512, nhead=8, num_encoder_layers=6,
+                 num_decoder_layers=6, dim_feedforward=2048, dropout=0.1,
+                 activation="relu", normalize_before=False,
+                 return_intermediate_dec=False):
+        super().__init__()
+
+        encoder_layer = TransformerEncoderLayer(d_model, nhead, dim_feedforward,
+                                                dropout, activation, normalize_before)
+        encoder_norm = nn.LayerNorm(d_model) if normalize_before else None
+        self.encoder = TransformerEncoder(encoder_layer, num_encoder_layers, encoder_norm)
+
+        decoder_layer = TransformerDecoderLayer(d_model, nhead, dim_feedforward,
+                                                dropout, activation, normalize_before)
+        decoder_norm = nn.LayerNorm(d_model)
+        self.decoder = TransformerDecoder(decoder_layer, num_decoder_layers, decoder_norm,
+                                          return_intermediate=return_intermediate_dec)
+
+        self._reset_parameters()
+
+        self.d_model = d_model
+        self.nhead = nhead
+
+    def _reset_parameters(self):
+        for p in self.parameters():
+            if p.dim() > 1:
+                nn.init.xavier_uniform_(p)
+
+    def forward(self, src, mask, query_embed, pos_embed, latent_input=None, proprio_input=None, additional_pos_embed=None):
+        # TODO flatten only when input has H and W
+        if len(src.shape) == 4: # has H and W
+            # flatten NxCxHxW to HWxNxC
+            bs, c, h, w = src.shape
+            src = src.flatten(2).permute(2, 0, 1)
+            pos_embed = pos_embed.flatten(2).permute(2, 0, 1).repeat(1, bs, 1)
+            query_embed = query_embed.unsqueeze(1).repeat(1, bs, 1)
+            # mask = mask.flatten(1)
+
+            additional_pos_embed = additional_pos_embed.unsqueeze(1).repeat(1, bs, 1) # seq, bs, dim
+            pos_embed = torch.cat([additional_pos_embed, pos_embed], axis=0)
+
+            addition_input = torch.stack([latent_input, proprio_input], axis=0)
+            src = torch.cat([addition_input, src], axis=0)
+        else:
+            assert len(src.shape) == 3
+            # flatten NxHWxC to HWxNxC
+            bs, hw, c = src.shape
+            src = src.permute(1, 0, 2)
+            pos_embed = pos_embed.unsqueeze(1).repeat(1, bs, 1)
+            query_embed = query_embed.unsqueeze(1).repeat(1, bs, 1)
+
+        tgt = torch.zeros_like(query_embed)
+        memory = self.encoder(src, src_key_padding_mask=mask, pos=pos_embed)
+        hs = self.decoder(tgt, memory, memory_key_padding_mask=mask,
+                          pos=pos_embed, query_pos=query_embed)
+        hs = hs.transpose(1, 2)
+        return hs
+
+class TransformerEncoder(nn.Module):
+
+    def __init__(self, encoder_layer, num_layers, norm=None):
+        super().__init__()
+        self.layers = _get_clones(encoder_layer, num_layers)
+        self.num_layers = num_layers
+        self.norm = norm
+
+    def forward(self, src,
+                mask: Optional[Tensor] = None,
+                src_key_padding_mask: Optional[Tensor] = None,
+                pos: Optional[Tensor] = None):
+        output = src
+
+        for layer in self.layers:
+            output = layer(output, src_mask=mask,
+                           src_key_padding_mask=src_key_padding_mask, pos=pos)
+
+        if self.norm is not None:
+            output = self.norm(output)
+
+        return output
+
+
+class TransformerDecoder(nn.Module):
+
+    def __init__(self, decoder_layer, num_layers, norm=None, return_intermediate=False):
+        super().__init__()
+        self.layers = _get_clones(decoder_layer, num_layers)
+        self.num_layers = num_layers
+        self.norm = norm
+        self.return_intermediate = return_intermediate
+
+    def forward(self, tgt, memory,
+                tgt_mask: Optional[Tensor] = None,
+                memory_mask: Optional[Tensor] = None,
+                tgt_key_padding_mask: Optional[Tensor] = None,
+                memory_key_padding_mask: Optional[Tensor] = None,
+                pos: Optional[Tensor] = None,
+                query_pos: Optional[Tensor] = None):
+        output = tgt
+
+        intermediate = []
+
+        for layer in self.layers:
+            output = layer(output, memory, tgt_mask=tgt_mask,
+                           memory_mask=memory_mask,
+                           tgt_key_padding_mask=tgt_key_padding_mask,
+                           memory_key_padding_mask=memory_key_padding_mask,
+                           pos=pos, query_pos=query_pos)
+            if self.return_intermediate:
+                intermediate.append(self.norm(output))
+
+        if self.norm is not None:
+            output = self.norm(output)
+            if self.return_intermediate:
+                intermediate.pop()
+                intermediate.append(output)
+
+        if self.return_intermediate:
+            return torch.stack(intermediate)
+
+        return output.unsqueeze(0)
+
+
+class TransformerEncoderLayer(nn.Module):
+
+    def __init__(self, d_model, nhead, dim_feedforward=2048, dropout=0.1,
+                 activation="relu", normalize_before=False):
+        super().__init__()
+        self.self_attn = nn.MultiheadAttention(d_model, nhead, dropout=dropout)
+        # Implementation of Feedforward model
+        self.linear1 = nn.Linear(d_model, dim_feedforward)
+        self.dropout = nn.Dropout(dropout)
+        self.linear2 = nn.Linear(dim_feedforward, d_model)
+
+        self.norm1 = nn.LayerNorm(d_model)
+        self.norm2 = nn.LayerNorm(d_model)
+        self.dropout1 = nn.Dropout(dropout)
+        self.dropout2 = nn.Dropout(dropout)
+
+        self.activation = _get_activation_fn(activation)
+        self.normalize_before = normalize_before
+
+    def with_pos_embed(self, tensor, pos: Optional[Tensor]):
+        return tensor if pos is None else tensor + pos
+
+    def forward_post(self,
+                     src,
+                     src_mask: Optional[Tensor] = None,
+                     src_key_padding_mask: Optional[Tensor] = None,
+                     pos: Optional[Tensor] = None):
+        q = k = self.with_pos_embed(src, pos)
+        src2 = self.self_attn(q, k, value=src, attn_mask=src_mask,
+                              key_padding_mask=src_key_padding_mask)[0]
+        src = src + self.dropout1(src2)
+        src = self.norm1(src)
+        src2 = self.linear2(self.dropout(self.activation(self.linear1(src))))
+        src = src + self.dropout2(src2)
+        src = self.norm2(src)
+        return src
+
+    def forward_pre(self, src,
+                    src_mask: Optional[Tensor] = None,
+                    src_key_padding_mask: Optional[Tensor] = None,
+                    pos: Optional[Tensor] = None):
+        src2 = self.norm1(src)
+        q = k = self.with_pos_embed(src2, pos)
+        src2 = self.self_attn(q, k, value=src2, attn_mask=src_mask,
+                              key_padding_mask=src_key_padding_mask)[0]
+        src = src + self.dropout1(src2)
+        src2 = self.norm2(src)
+        src2 = self.linear2(self.dropout(self.activation(self.linear1(src2))))
+        src = src + self.dropout2(src2)
+        return src
+
+    def forward(self, src,
+                src_mask: Optional[Tensor] = None,
+                src_key_padding_mask: Optional[Tensor] = None,
+                pos: Optional[Tensor] = None):
+        if self.normalize_before:
+            return self.forward_pre(src, src_mask, src_key_padding_mask, pos)
+        return self.forward_post(src, src_mask, src_key_padding_mask, pos)
+
+
+class TransformerDecoderLayer(nn.Module):
+
+    def __init__(self, d_model, nhead, dim_feedforward=2048, dropout=0.1,
+                 activation="relu", normalize_before=False):
+        super().__init__()
+        self.self_attn = nn.MultiheadAttention(d_model, nhead, dropout=dropout)
+        self.multihead_attn = nn.MultiheadAttention(d_model, nhead, dropout=dropout)
+        # Implementation of Feedforward model
+        self.linear1 = nn.Linear(d_model, dim_feedforward)
+        self.dropout = nn.Dropout(dropout)
+        self.linear2 = nn.Linear(dim_feedforward, d_model)
+
+        self.norm1 = nn.LayerNorm(d_model)
+        self.norm2 = nn.LayerNorm(d_model)
+        self.norm3 = nn.LayerNorm(d_model)
+        self.dropout1 = nn.Dropout(dropout)
+        self.dropout2 = nn.Dropout(dropout)
+        self.dropout3 = nn.Dropout(dropout)
+
+        self.activation = _get_activation_fn(activation)
+        self.normalize_before = normalize_before
+
+    def with_pos_embed(self, tensor, pos: Optional[Tensor]):
+        return tensor if pos is None else tensor + pos
+
+    def forward_post(self, tgt, memory,
+                     tgt_mask: Optional[Tensor] = None,
+                     memory_mask: Optional[Tensor] = None,
+                     tgt_key_padding_mask: Optional[Tensor] = None,
+                     memory_key_padding_mask: Optional[Tensor] = None,
+                     pos: Optional[Tensor] = None,
+                     query_pos: Optional[Tensor] = None):
+        q = k = self.with_pos_embed(tgt, query_pos)
+        tgt2 = self.self_attn(q, k, value=tgt, attn_mask=tgt_mask,
+                              key_padding_mask=tgt_key_padding_mask)[0]
+        tgt = tgt + self.dropout1(tgt2)
+        tgt = self.norm1(tgt)
+        tgt2 = self.multihead_attn(query=self.with_pos_embed(tgt, query_pos),
+                                   key=self.with_pos_embed(memory, pos),
+                                   value=memory, attn_mask=memory_mask,
+                                   key_padding_mask=memory_key_padding_mask)[0]
+        tgt = tgt + self.dropout2(tgt2)
+        tgt = self.norm2(tgt)
+        tgt2 = self.linear2(self.dropout(self.activation(self.linear1(tgt))))
+        tgt = tgt + self.dropout3(tgt2)
+        tgt = self.norm3(tgt)
+        return tgt
+
+    def forward_pre(self, tgt, memory,
+                    tgt_mask: Optional[Tensor] = None,
+                    memory_mask: Optional[Tensor] = None,
+                    tgt_key_padding_mask: Optional[Tensor] = None,
+                    memory_key_padding_mask: Optional[Tensor] = None,
+                    pos: Optional[Tensor] = None,
+                    query_pos: Optional[Tensor] = None):
+        tgt2 = self.norm1(tgt)
+        q = k = self.with_pos_embed(tgt2, query_pos)
+        tgt2 = self.self_attn(q, k, value=tgt2, attn_mask=tgt_mask,
+                              key_padding_mask=tgt_key_padding_mask)[0]
+        tgt = tgt + self.dropout1(tgt2)
+        tgt2 = self.norm2(tgt)
+        tgt2 = self.multihead_attn(query=self.with_pos_embed(tgt2, query_pos),
+                                   key=self.with_pos_embed(memory, pos),
+                                   value=memory, attn_mask=memory_mask,
+                                   key_padding_mask=memory_key_padding_mask)[0]
+        tgt = tgt + self.dropout2(tgt2)
+        tgt2 = self.norm3(tgt)
+        tgt2 = self.linear2(self.dropout(self.activation(self.linear1(tgt2))))
+        tgt = tgt + self.dropout3(tgt2)
+        return tgt
+
+    def forward(self, tgt, memory,
+                tgt_mask: Optional[Tensor] = None,
+                memory_mask: Optional[Tensor] = None,
+                tgt_key_padding_mask: Optional[Tensor] = None,
+                memory_key_padding_mask: Optional[Tensor] = None,
+                pos: Optional[Tensor] = None,
+                query_pos: Optional[Tensor] = None):
+        if self.normalize_before:
+            return self.forward_pre(tgt, memory, tgt_mask, memory_mask,
+                                    tgt_key_padding_mask, memory_key_padding_mask, pos, query_pos)
+        return self.forward_post(tgt, memory, tgt_mask, memory_mask,
+                                 tgt_key_padding_mask, memory_key_padding_mask, pos, query_pos)
+
+
+def _get_clones(module, N):
+    return nn.ModuleList([copy.deepcopy(module) for i in range(N)])
+
+
+def build_transformer(args):
+    return Transformer(
+        d_model=args.hidden_dim,
+        dropout=args.dropout,
+        nhead=args.nheads,
+        dim_feedforward=args.dim_feedforward,
+        num_encoder_layers=args.enc_layers,
+        num_decoder_layers=args.dec_layers,
+        normalize_before=args.pre_norm,
+        return_intermediate_dec=True,
+    )
+
+
+def _get_activation_fn(activation):
+    """Return an activation function given a string"""
+    if activation == "relu":
+        return F.relu
+    if activation == "gelu":
+        return F.gelu
+    if activation == "glu":
+        return F.glu
+    raise RuntimeError(F"activation should be relu/gelu, not {activation}.")
diff --git a/roboimi/ddt/policy.py b/roboimi/ddt/policy.py
new file mode 100644
index 0000000..3b79b09
--- /dev/null
+++ b/roboimi/ddt/policy.py
@@ -0,0 +1,147 @@
+"""
+DDT Policy - 基于扩散模型的动作生成策略。
+
+支持 Flow Matching 训练和推理。
+"""
+import torch
+import torch.nn as nn
+from torch.nn import functional as F
+import torchvision.transforms as transforms
+from torchvision.transforms import v2
+import math
+
+from roboimi.ddt.main import build_DDT_model_and_optimizer
+
+
+class DDTPolicy(nn.Module):
+    """DDT (Decoupled Diffusion Transformer) 策略。
+    
+    使用 Flow Matching 进行训练，支持多步扩散采样推理。
+    带数据增强，适配 DINOv2 等 ViT backbone。
+    
+    Args:
+        args_override: 配置参数字典
+            - num_inference_steps: 推理时的扩散步数
+            - qpos_noise_std: qpos 噪声标准差（训练时数据增强）
+            - patch_h, patch_w: 图像 patch 数量（用于计算目标尺寸）
+    """
+    
+    def __init__(self, args_override):
+        super().__init__()
+        model, optimizer = build_DDT_model_and_optimizer(args_override)
+        self.model = model
+        self.optimizer = optimizer
+        
+        self.num_inference_steps = args_override.get('num_inference_steps', 10)
+        self.qpos_noise_std = args_override.get('qpos_noise_std', 0.0)
+        
+        # 图像尺寸配置 (适配 DINOv2)
+        self.patch_h = args_override.get('patch_h', 16)
+        self.patch_w = args_override.get('patch_w', 22)
+        
+        print(f'DDT Policy: {self.num_inference_steps} steps, '
+              f'image size ({self.patch_h*14}, {self.patch_w*14})')
+    
+    def __call__(self, qpos, image, actions=None, is_pad=None):
+        """前向传播。
+        
+        训练时: 使用 Flow Matching 损失
+        推理时: 通过扩散采样生成动作
+        
+        Args:
+            qpos: 机器人关节状态 [B, state_dim]
+            image: 多相机图像 [B, num_cam, C, H, W]
+            actions: 目标动作序列 [B, T, action_dim]（训练时提供）
+            is_pad: padding 标记 [B, T]
+        
+        Returns:
+            训练时: loss_dict
+            推理时: 预测的动作序列 [B, T, action_dim]
+        """
+        env_state = None
+        
+        # 图像预处理
+        if actions is not None:  # 训练时：数据增强
+            transform = v2.Compose([
+                v2.ColorJitter(brightness=0.5, contrast=0.5, saturation=0.5, hue=0.5),
+                v2.RandomPerspective(distortion_scale=0.5),
+                v2.RandomAffine(degrees=10, translate=(0.1, 0.1), scale=(0.9, 1.1)),
+                v2.GaussianBlur(kernel_size=(9, 9), sigma=(0.1, 2.0)),
+                v2.Resize((self.patch_h * 14, self.patch_w * 14)),
+                v2.Normalize(mean=(0.485, 0.456, 0.406), std=(0.229, 0.224, 0.225)),
+            ])
+            if self.qpos_noise_std > 0:
+                qpos = qpos + (self.qpos_noise_std ** 0.5) * torch.randn_like(qpos)
+        else:  # 推理时
+            transform = v2.Compose([
+                v2.Resize((self.patch_h * 14, self.patch_w * 14)),
+                v2.Normalize(mean=(0.485, 0.456, 0.406), std=(0.229, 0.224, 0.225)),
+            ])
+        
+        image = transform(image)
+        
+        if actions is not None:
+            actions = actions[:, :self.model.num_queries]
+            is_pad = is_pad[:, :self.model.num_queries]
+            loss_dict = self._compute_loss(qpos, image, actions, is_pad)
+            return loss_dict
+        else:
+            a_hat = self._sample(qpos, image)
+            return a_hat
+    
+    def _compute_loss(self, qpos, image, actions, is_pad):
+        """计算 Flow Matching 损失。
+        
+        Flow Matching 目标: 学习从噪声到数据的向量场
+        损失: ||v_theta(x_t, t) - (x_1 - x_0)||^2
+        其中 x_t = (1-t)*x_0 + t*x_1, x_0 是噪声, x_1 是目标动作
+        """
+        B, T, action_dim = actions.shape
+        device = actions.device
+        
+        t = torch.rand(B, device=device)
+        noise = torch.randn_like(actions)
+        
+        t_expand = t.view(B, 1, 1).expand(B, T, action_dim)
+        x_t = (1 - t_expand) * noise + t_expand * actions
+        target_velocity = actions - noise
+        
+        pred_velocity, _ = self.model(
+            qpos=qpos,
+            image=image,
+            env_state=None,
+            actions=x_t,
+            timesteps=t,
+        )
+        
+        all_loss = F.mse_loss(pred_velocity, target_velocity, reduction='none')
+        loss = (all_loss * ~is_pad.unsqueeze(-1)).mean()
+        
+        return {'flow_loss': loss, 'loss': loss}
+    
+    @torch.no_grad()
+    def _sample(self, qpos, image):
+        """通过 ODE 求解进行扩散采样。
+        
+        使用 Euler 方法从 t=0 积分到 t=1:
+        x_{t+dt} = x_t + v_theta(x_t, t) * dt
+        """
+        B = qpos.shape[0]
+        T = self.model.num_queries
+        action_dim = self.model.action_dim
+        device = qpos.device
+        
+        x = torch.randn(B, T, action_dim, device=device)
+        obs = self.model.encode_observations(qpos, image)
+        
+        dt = 1.0 / self.num_inference_steps
+        for i in range(self.num_inference_steps):
+            t = torch.full((B,), i * dt, device=device)
+            velocity, _ = self.model.action_ddt(x=x, t=t, obs=obs)
+            x = x + velocity * dt
+        
+        return x
+    
+    def configure_optimizers(self):
+        """返回优化器。"""
+        return self.optimizer
diff --git a/roboimi/ddt/util/__init__.py b/roboimi/ddt/util/__init__.py
new file mode 100644
index 0000000..168f997
--- /dev/null
+++ b/roboimi/ddt/util/__init__.py
@@ -0,0 +1 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
diff --git a/roboimi/ddt/util/box_ops.py b/roboimi/ddt/util/box_ops.py
new file mode 100644
index 0000000..9c088e5
--- /dev/null
+++ b/roboimi/ddt/util/box_ops.py
@@ -0,0 +1,88 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+Utilities for bounding box manipulation and GIoU.
+"""
+import torch
+from torchvision.ops.boxes import box_area
+
+
+def box_cxcywh_to_xyxy(x):
+    x_c, y_c, w, h = x.unbind(-1)
+    b = [(x_c - 0.5 * w), (y_c - 0.5 * h),
+         (x_c + 0.5 * w), (y_c + 0.5 * h)]
+    return torch.stack(b, dim=-1)
+
+
+def box_xyxy_to_cxcywh(x):
+    x0, y0, x1, y1 = x.unbind(-1)
+    b = [(x0 + x1) / 2, (y0 + y1) / 2,
+         (x1 - x0), (y1 - y0)]
+    return torch.stack(b, dim=-1)
+
+
+# modified from torchvision to also return the union
+def box_iou(boxes1, boxes2):
+    area1 = box_area(boxes1)
+    area2 = box_area(boxes2)
+
+    lt = torch.max(boxes1[:, None, :2], boxes2[:, :2])  # [N,M,2]
+    rb = torch.min(boxes1[:, None, 2:], boxes2[:, 2:])  # [N,M,2]
+
+    wh = (rb - lt).clamp(min=0)  # [N,M,2]
+    inter = wh[:, :, 0] * wh[:, :, 1]  # [N,M]
+
+    union = area1[:, None] + area2 - inter
+
+    iou = inter / union
+    return iou, union
+
+
+def generalized_box_iou(boxes1, boxes2):
+    """
+    Generalized IoU from https://giou.stanford.edu/
+
+    The boxes should be in [x0, y0, x1, y1] format
+
+    Returns a [N, M] pairwise matrix, where N = len(boxes1)
+    and M = len(boxes2)
+    """
+    # degenerate boxes gives inf / nan results
+    # so do an early check
+    assert (boxes1[:, 2:] >= boxes1[:, :2]).all()
+    assert (boxes2[:, 2:] >= boxes2[:, :2]).all()
+    iou, union = box_iou(boxes1, boxes2)
+
+    lt = torch.min(boxes1[:, None, :2], boxes2[:, :2])
+    rb = torch.max(boxes1[:, None, 2:], boxes2[:, 2:])
+
+    wh = (rb - lt).clamp(min=0)  # [N,M,2]
+    area = wh[:, :, 0] * wh[:, :, 1]
+
+    return iou - (area - union) / area
+
+
+def masks_to_boxes(masks):
+    """Compute the bounding boxes around the provided masks
+
+    The masks should be in format [N, H, W] where N is the number of masks, (H, W) are the spatial dimensions.
+
+    Returns a [N, 4] tensors, with the boxes in xyxy format
+    """
+    if masks.numel() == 0:
+        return torch.zeros((0, 4), device=masks.device)
+
+    h, w = masks.shape[-2:]
+
+    y = torch.arange(0, h, dtype=torch.float)
+    x = torch.arange(0, w, dtype=torch.float)
+    y, x = torch.meshgrid(y, x)
+
+    x_mask = (masks * x.unsqueeze(0))
+    x_max = x_mask.flatten(1).max(-1)[0]
+    x_min = x_mask.masked_fill(~(masks.bool()), 1e8).flatten(1).min(-1)[0]
+
+    y_mask = (masks * y.unsqueeze(0))
+    y_max = y_mask.flatten(1).max(-1)[0]
+    y_min = y_mask.masked_fill(~(masks.bool()), 1e8).flatten(1).min(-1)[0]
+
+    return torch.stack([x_min, y_min, x_max, y_max], 1)
diff --git a/roboimi/ddt/util/misc.py b/roboimi/ddt/util/misc.py
new file mode 100644
index 0000000..dfa9fb5
--- /dev/null
+++ b/roboimi/ddt/util/misc.py
@@ -0,0 +1,468 @@
+# Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved
+"""
+Misc functions, including distributed helpers.
+
+Mostly copy-paste from torchvision references.
+"""
+import os
+import subprocess
+import time
+from collections import defaultdict, deque
+import datetime
+import pickle
+from packaging import version
+from typing import Optional, List
+
+import torch
+import torch.distributed as dist
+from torch import Tensor
+
+# needed due to empty tensor bug in pytorch and torchvision 0.5
+import torchvision
+if version.parse(torchvision.__version__) < version.parse('0.7'):
+    from torchvision.ops import _new_empty_tensor
+    from torchvision.ops.misc import _output_size
+
+
+class SmoothedValue(object):
+    """Track a series of values and provide access to smoothed values over a
+    window or the global series average.
+    """
+
+    def __init__(self, window_size=20, fmt=None):
+        if fmt is None:
+            fmt = "{median:.4f} ({global_avg:.4f})"
+        self.deque = deque(maxlen=window_size)
+        self.total = 0.0
+        self.count = 0
+        self.fmt = fmt
+
+    def update(self, value, n=1):
+        self.deque.append(value)
+        self.count += n
+        self.total += value * n
+
+    def synchronize_between_processes(self):
+        """
+        Warning: does not synchronize the deque!
+        """
+        if not is_dist_avail_and_initialized():
+            return
+        t = torch.tensor([self.count, self.total], dtype=torch.float64, device='cuda')
+        dist.barrier()
+        dist.all_reduce(t)
+        t = t.tolist()
+        self.count = int(t[0])
+        self.total = t[1]
+
+    @property
+    def median(self):
+        d = torch.tensor(list(self.deque))
+        return d.median().item()
+
+    @property
+    def avg(self):
+        d = torch.tensor(list(self.deque), dtype=torch.float32)
+        return d.mean().item()
+
+    @property
+    def global_avg(self):
+        return self.total / self.count
+
+    @property
+    def max(self):
+        return max(self.deque)
+
+    @property
+    def value(self):
+        return self.deque[-1]
+
+    def __str__(self):
+        return self.fmt.format(
+            median=self.median,
+            avg=self.avg,
+            global_avg=self.global_avg,
+            max=self.max,
+            value=self.value)
+
+
+def all_gather(data):
+    """
+    Run all_gather on arbitrary picklable data (not necessarily tensors)
+    Args:
+        data: any picklable object
+    Returns:
+        list[data]: list of data gathered from each rank
+    """
+    world_size = get_world_size()
+    if world_size == 1:
+        return [data]
+
+    # serialized to a Tensor
+    buffer = pickle.dumps(data)
+    storage = torch.ByteStorage.from_buffer(buffer)
+    tensor = torch.ByteTensor(storage).to("cuda")
+
+    # obtain Tensor size of each rank
+    local_size = torch.tensor([tensor.numel()], device="cuda")
+    size_list = [torch.tensor([0], device="cuda") for _ in range(world_size)]
+    dist.all_gather(size_list, local_size)
+    size_list = [int(size.item()) for size in size_list]
+    max_size = max(size_list)
+
+    # receiving Tensor from all ranks
+    # we pad the tensor because torch all_gather does not support
+    # gathering tensors of different shapes
+    tensor_list = []
+    for _ in size_list:
+        tensor_list.append(torch.empty((max_size,), dtype=torch.uint8, device="cuda"))
+    if local_size != max_size:
+        padding = torch.empty(size=(max_size - local_size,), dtype=torch.uint8, device="cuda")
+        tensor = torch.cat((tensor, padding), dim=0)
+    dist.all_gather(tensor_list, tensor)
+
+    data_list = []
+    for size, tensor in zip(size_list, tensor_list):
+        buffer = tensor.cpu().numpy().tobytes()[:size]
+        data_list.append(pickle.loads(buffer))
+
+    return data_list
+
+
+def reduce_dict(input_dict, average=True):
+    """
+    Args:
+        input_dict (dict): all the values will be reduced
+        average (bool): whether to do average or sum
+    Reduce the values in the dictionary from all processes so that all processes
+    have the averaged results. Returns a dict with the same fields as
+    input_dict, after reduction.
+    """
+    world_size = get_world_size()
+    if world_size < 2:
+        return input_dict
+    with torch.no_grad():
+        names = []
+        values = []
+        # sort the keys so that they are consistent across processes
+        for k in sorted(input_dict.keys()):
+            names.append(k)
+            values.append(input_dict[k])
+        values = torch.stack(values, dim=0)
+        dist.all_reduce(values)
+        if average:
+            values /= world_size
+        reduced_dict = {k: v for k, v in zip(names, values)}
+    return reduced_dict
+
+
+class MetricLogger(object):
+    def __init__(self, delimiter="\t"):
+        self.meters = defaultdict(SmoothedValue)
+        self.delimiter = delimiter
+
+    def update(self, **kwargs):
+        for k, v in kwargs.items():
+            if isinstance(v, torch.Tensor):
+                v = v.item()
+            assert isinstance(v, (float, int))
+            self.meters[k].update(v)
+
+    def __getattr__(self, attr):
+        if attr in self.meters:
+            return self.meters[attr]
+        if attr in self.__dict__:
+            return self.__dict__[attr]
+        raise AttributeError("'{}' object has no attribute '{}'".format(
+            type(self).__name__, attr))
+
+    def __str__(self):
+        loss_str = []
+        for name, meter in self.meters.items():
+            loss_str.append(
+                "{}: {}".format(name, str(meter))
+            )
+        return self.delimiter.join(loss_str)
+
+    def synchronize_between_processes(self):
+        for meter in self.meters.values():
+            meter.synchronize_between_processes()
+
+    def add_meter(self, name, meter):
+        self.meters[name] = meter
+
+    def log_every(self, iterable, print_freq, header=None):
+        i = 0
+        if not header:
+            header = ''
+        start_time = time.time()
+        end = time.time()
+        iter_time = SmoothedValue(fmt='{avg:.4f}')
+        data_time = SmoothedValue(fmt='{avg:.4f}')
+        space_fmt = ':' + str(len(str(len(iterable)))) + 'd'
+        if torch.cuda.is_available():
+            log_msg = self.delimiter.join([
+                header,
+                '[{0' + space_fmt + '}/{1}]',
+                'eta: {eta}',
+                '{meters}',
+                'time: {time}',
+                'data: {data}',
+                'max mem: {memory:.0f}'
+            ])
+        else:
+            log_msg = self.delimiter.join([
+                header,
+                '[{0' + space_fmt + '}/{1}]',
+                'eta: {eta}',
+                '{meters}',
+                'time: {time}',
+                'data: {data}'
+            ])
+        MB = 1024.0 * 1024.0
+        for obj in iterable:
+            data_time.update(time.time() - end)
+            yield obj
+            iter_time.update(time.time() - end)
+            if i % print_freq == 0 or i == len(iterable) - 1:
+                eta_seconds = iter_time.global_avg * (len(iterable) - i)
+                eta_string = str(datetime.timedelta(seconds=int(eta_seconds)))
+                if torch.cuda.is_available():
+                    print(log_msg.format(
+                        i, len(iterable), eta=eta_string,
+                        meters=str(self),
+                        time=str(iter_time), data=str(data_time),
+                        memory=torch.cuda.max_memory_allocated() / MB))
+                else:
+                    print(log_msg.format(
+                        i, len(iterable), eta=eta_string,
+                        meters=str(self),
+                        time=str(iter_time), data=str(data_time)))
+            i += 1
+            end = time.time()
+        total_time = time.time() - start_time
+        total_time_str = str(datetime.timedelta(seconds=int(total_time)))
+        print('{} Total time: {} ({:.4f} s / it)'.format(
+            header, total_time_str, total_time / len(iterable)))
+
+
+def get_sha():
+    cwd = os.path.dirname(os.path.abspath(__file__))
+
+    def _run(command):
+        return subprocess.check_output(command, cwd=cwd).decode('ascii').strip()
+    sha = 'N/A'
+    diff = "clean"
+    branch = 'N/A'
+    try:
+        sha = _run(['git', 'rev-parse', 'HEAD'])
+        subprocess.check_output(['git', 'diff'], cwd=cwd)
+        diff = _run(['git', 'diff-index', 'HEAD'])
+        diff = "has uncommited changes" if diff else "clean"
+        branch = _run(['git', 'rev-parse', '--abbrev-ref', 'HEAD'])
+    except Exception:
+        pass
+    message = f"sha: {sha}, status: {diff}, branch: {branch}"
+    return message
+
+
+def collate_fn(batch):
+    batch = list(zip(*batch))
+    batch[0] = nested_tensor_from_tensor_list(batch[0])
+    return tuple(batch)
+
+
+def _max_by_axis(the_list):
+    # type: (List[List[int]]) -> List[int]
+    maxes = the_list[0]
+    for sublist in the_list[1:]:
+        for index, item in enumerate(sublist):
+            maxes[index] = max(maxes[index], item)
+    return maxes
+
+
+class NestedTensor(object):
+    def __init__(self, tensors, mask: Optional[Tensor]):
+        self.tensors = tensors
+        self.mask = mask
+
+    def to(self, device):
+        # type: (Device) -> NestedTensor # noqa
+        cast_tensor = self.tensors.to(device)
+        mask = self.mask
+        if mask is not None:
+            assert mask is not None
+            cast_mask = mask.to(device)
+        else:
+            cast_mask = None
+        return NestedTensor(cast_tensor, cast_mask)
+
+    def decompose(self):
+        return self.tensors, self.mask
+
+    def __repr__(self):
+        return str(self.tensors)
+
+
+def nested_tensor_from_tensor_list(tensor_list: List[Tensor]):
+    # TODO make this more general
+    if tensor_list[0].ndim == 3:
+        if torchvision._is_tracing():
+            # nested_tensor_from_tensor_list() does not export well to ONNX
+            # call _onnx_nested_tensor_from_tensor_list() instead
+            return _onnx_nested_tensor_from_tensor_list(tensor_list)
+
+        # TODO make it support different-sized images
+        max_size = _max_by_axis([list(img.shape) for img in tensor_list])
+        # min_size = tuple(min(s) for s in zip(*[img.shape for img in tensor_list]))
+        batch_shape = [len(tensor_list)] + max_size
+        b, c, h, w = batch_shape
+        dtype = tensor_list[0].dtype
+        device = tensor_list[0].device
+        tensor = torch.zeros(batch_shape, dtype=dtype, device=device)
+        mask = torch.ones((b, h, w), dtype=torch.bool, device=device)
+        for img, pad_img, m in zip(tensor_list, tensor, mask):
+            pad_img[: img.shape[0], : img.shape[1], : img.shape[2]].copy_(img)
+            m[: img.shape[1], :img.shape[2]] = False
+    else:
+        raise ValueError('not supported')
+    return NestedTensor(tensor, mask)
+
+
+# _onnx_nested_tensor_from_tensor_list() is an implementation of
+# nested_tensor_from_tensor_list() that is supported by ONNX tracing.
+@torch.jit.unused
+def _onnx_nested_tensor_from_tensor_list(tensor_list: List[Tensor]) -> NestedTensor:
+    max_size = []
+    for i in range(tensor_list[0].dim()):
+        max_size_i = torch.max(torch.stack([img.shape[i] for img in tensor_list]).to(torch.float32)).to(torch.int64)
+        max_size.append(max_size_i)
+    max_size = tuple(max_size)
+
+    # work around for
+    # pad_img[: img.shape[0], : img.shape[1], : img.shape[2]].copy_(img)
+    # m[: img.shape[1], :img.shape[2]] = False
+    # which is not yet supported in onnx
+    padded_imgs = []
+    padded_masks = []
+    for img in tensor_list:
+        padding = [(s1 - s2) for s1, s2 in zip(max_size, tuple(img.shape))]
+        padded_img = torch.nn.functional.pad(img, (0, padding[2], 0, padding[1], 0, padding[0]))
+        padded_imgs.append(padded_img)
+
+        m = torch.zeros_like(img[0], dtype=torch.int, device=img.device)
+        padded_mask = torch.nn.functional.pad(m, (0, padding[2], 0, padding[1]), "constant", 1)
+        padded_masks.append(padded_mask.to(torch.bool))
+
+    tensor = torch.stack(padded_imgs)
+    mask = torch.stack(padded_masks)
+
+    return NestedTensor(tensor, mask=mask)
+
+
+def setup_for_distributed(is_master):
+    """
+    This function disables printing when not in master process
+    """
+    import builtins as __builtin__
+    builtin_print = __builtin__.print
+
+    def print(*args, **kwargs):
+        force = kwargs.pop('force', False)
+        if is_master or force:
+            builtin_print(*args, **kwargs)
+
+    __builtin__.print = print
+
+
+def is_dist_avail_and_initialized():
+    if not dist.is_available():
+        return False
+    if not dist.is_initialized():
+        return False
+    return True
+
+
+def get_world_size():
+    if not is_dist_avail_and_initialized():
+        return 1
+    return dist.get_world_size()
+
+
+def get_rank():
+    if not is_dist_avail_and_initialized():
+        return 0
+    return dist.get_rank()
+
+
+def is_main_process():
+    return get_rank() == 0
+
+
+def save_on_master(*args, **kwargs):
+    if is_main_process():
+        torch.save(*args, **kwargs)
+
+
+def init_distributed_mode(args):
+    if 'RANK' in os.environ and 'WORLD_SIZE' in os.environ:
+        args.rank = int(os.environ["RANK"])
+        args.world_size = int(os.environ['WORLD_SIZE'])
+        args.gpu = int(os.environ['LOCAL_RANK'])
+    elif 'SLURM_PROCID' in os.environ:
+        args.rank = int(os.environ['SLURM_PROCID'])
+        args.gpu = args.rank % torch.cuda.device_count()
+    else:
+        print('Not using distributed mode')
+        args.distributed = False
+        return
+
+    args.distributed = True
+
+    torch.cuda.set_device(args.gpu)
+    args.dist_backend = 'nccl'
+    print('| distributed init (rank {}): {}'.format(
+        args.rank, args.dist_url), flush=True)
+    torch.distributed.init_process_group(backend=args.dist_backend, init_method=args.dist_url,
+                                         world_size=args.world_size, rank=args.rank)
+    torch.distributed.barrier()
+    setup_for_distributed(args.rank == 0)
+
+
+@torch.no_grad()
+def accuracy(output, target, topk=(1,)):
+    """Computes the precision@k for the specified values of k"""
+    if target.numel() == 0:
+        return [torch.zeros([], device=output.device)]
+    maxk = max(topk)
+    batch_size = target.size(0)
+
+    _, pred = output.topk(maxk, 1, True, True)
+    pred = pred.t()
+    correct = pred.eq(target.view(1, -1).expand_as(pred))
+
+    res = []
+    for k in topk:
+        correct_k = correct[:k].view(-1).float().sum(0)
+        res.append(correct_k.mul_(100.0 / batch_size))
+    return res
+
+
+def interpolate(input, size=None, scale_factor=None, mode="nearest", align_corners=None):
+    # type: (Tensor, Optional[List[int]], Optional[float], str, Optional[bool]) -> Tensor
+    """
+    Equivalent to nn.functional.interpolate, but with support for empty batch sizes.
+    This will eventually be supported natively by PyTorch, and this
+    class can go away.
+    """
+    if version.parse(torchvision.__version__) < version.parse('0.7'):
+        if input.numel() > 0:
+            return torch.nn.functional.interpolate(
+                input, size, scale_factor, mode, align_corners
+            )
+
+        output_shape = _output_size(2, input, size, scale_factor)
+        output_shape = list(input.shape[:-2]) + list(output_shape)
+        return _new_empty_tensor(input, output_shape)
+    else:
+        return torchvision.ops.misc.interpolate(input, size, scale_factor, mode, align_corners)
diff --git a/roboimi/ddt/util/plot_utils.py b/roboimi/ddt/util/plot_utils.py
new file mode 100644
index 0000000..0f24bed
--- /dev/null
+++ b/roboimi/ddt/util/plot_utils.py
@@ -0,0 +1,107 @@
+"""
+Plotting utilities to visualize training logs.
+"""
+import torch
+import pandas as pd
+import numpy as np
+import seaborn as sns
+import matplotlib.pyplot as plt
+
+from pathlib import Path, PurePath
+
+
+def plot_logs(logs, fields=('class_error', 'loss_bbox_unscaled', 'mAP'), ewm_col=0, log_name='log.txt'):
+    '''
+    Function to plot specific fields from training log(s). Plots both training and test results.
+
+    :: Inputs - logs = list containing Path objects, each pointing to individual dir with a log file
+              - fields = which results to plot from each log file - plots both training and test for each field.
+              - ewm_col = optional, which column to use as the exponential weighted smoothing of the plots
+              - log_name = optional, name of log file if different than default 'log.txt'.
+
+    :: Outputs - matplotlib plots of results in fields, color coded for each log file.
+               - solid lines are training results, dashed lines are test results.
+
+    '''
+    func_name = "plot_utils.py::plot_logs"
+
+    # verify logs is a list of Paths (list[Paths]) or single Pathlib object Path,
+    # convert single Path to list to avoid 'not iterable' error
+
+    if not isinstance(logs, list):
+        if isinstance(logs, PurePath):
+            logs = [logs]
+            print(f"{func_name} info: logs param expects a list argument, converted to list[Path].")
+        else:
+            raise ValueError(f"{func_name} - invalid argument for logs parameter.\n \
+            Expect list[Path] or single Path obj, received {type(logs)}")
+
+    # Quality checks - verify valid dir(s), that every item in list is Path object, and that log_name exists in each dir
+    for i, dir in enumerate(logs):
+        if not isinstance(dir, PurePath):
+            raise ValueError(f"{func_name} - non-Path object in logs argument of {type(dir)}: \n{dir}")
+        if not dir.exists():
+            raise ValueError(f"{func_name} - invalid directory in logs argument:\n{dir}")
+        # verify log_name exists
+        fn = Path(dir / log_name)
+        if not fn.exists():
+            print(f"-> missing {log_name}.  Have you gotten to Epoch 1 in training?")
+            print(f"--> full path of missing log file: {fn}")
+            return
+
+    # load log file(s) and plot
+    dfs = [pd.read_json(Path(p) / log_name, lines=True) for p in logs]
+
+    fig, axs = plt.subplots(ncols=len(fields), figsize=(16, 5))
+
+    for df, color in zip(dfs, sns.color_palette(n_colors=len(logs))):
+        for j, field in enumerate(fields):
+            if field == 'mAP':
+                coco_eval = pd.DataFrame(
+                    np.stack(df.test_coco_eval_bbox.dropna().values)[:, 1]
+                ).ewm(com=ewm_col).mean()
+                axs[j].plot(coco_eval, c=color)
+            else:
+                df.interpolate().ewm(com=ewm_col).mean().plot(
+                    y=[f'train_{field}', f'test_{field}'],
+                    ax=axs[j],
+                    color=[color] * 2,
+                    style=['-', '--']
+                )
+    for ax, field in zip(axs, fields):
+        ax.legend([Path(p).name for p in logs])
+        ax.set_title(field)
+
+
+def plot_precision_recall(files, naming_scheme='iter'):
+    if naming_scheme == 'exp_id':
+        # name becomes exp_id
+        names = [f.parts[-3] for f in files]
+    elif naming_scheme == 'iter':
+        names = [f.stem for f in files]
+    else:
+        raise ValueError(f'not supported {naming_scheme}')
+    fig, axs = plt.subplots(ncols=2, figsize=(16, 5))
+    for f, color, name in zip(files, sns.color_palette("Blues", n_colors=len(files)), names):
+        data = torch.load(f)
+        # precision is n_iou, n_points, n_cat, n_area, max_det
+        precision = data['precision']
+        recall = data['params'].recThrs
+        scores = data['scores']
+        # take precision for all classes, all areas and 100 detections
+        precision = precision[0, :, :, 0, -1].mean(1)
+        scores = scores[0, :, :, 0, -1].mean(1)
+        prec = precision.mean()
+        rec = data['recall'][0, :, 0, -1].mean()
+        print(f'{naming_scheme} {name}: mAP@50={prec * 100: 05.1f}, ' +
+              f'score={scores.mean():0.3f}, ' +
+              f'f1={2 * prec * rec / (prec + rec + 1e-8):0.3f}'
+              )
+        axs[0].plot(recall, precision, c=color)
+        axs[1].plot(recall, scores, c=color)
+
+    axs[0].set_title('Precision / Recall')
+    axs[0].legend(names)
+    axs[1].set_title('Scores / Recall')
+    axs[1].legend(names)
+    return fig, axs
diff --git a/roboimi/demos/config.yaml b/roboimi/demos/config.yaml
index 16ab129..31d6aff 100644
--- a/roboimi/demos/config.yaml
+++ b/roboimi/demos/config.yaml
@@ -9,6 +9,7 @@ temporal_agg: false
 # policy_class: "ACT"
 # backbone: 'resnet18'
 policy_class: "ACTTV"
+# policy_class: "DDT"
 backbone: 'dino_v2'
 
 seed: 0
@@ -39,7 +40,7 @@ camera_names: []  # leave empty here by default
 xml_dir:          # leave empty here by default
 
 # transformer settings
-batch_size: 15                          
+batch_size: 32                          
 state_dim: 16            
 action_dim: 16      
 lr_backbone: 0.00001        
@@ -56,5 +57,10 @@ lr: 0.00001
 kl_weight: 100              
 chunk_size: 10            
 hidden_dim: 512           
-dim_feedforward: 3200   
+dim_feedforward: 3200
+
+# DDT 特有参数
+num_blocks: 12              # Transformer blocks 数量
+mlp_ratio: 4.0              # MLP 维度比例
+num_inference_steps: 10     # 扩散推理步数   
 
diff --git a/roboimi/utils/model_interface.py b/roboimi/utils/model_interface.py
index 007b0f7..d5c7821 100644
--- a/roboimi/utils/model_interface.py
+++ b/roboimi/utils/model_interface.py
@@ -2,6 +2,7 @@ import os
 import torch
 from roboimi.utils.utils import load_data, set_seed
 from roboimi.detr.policy import ACTPolicy, CNNMLPPolicy,ACTTVPolicy
+from roboimi.ddt.policy import DDTPolicy
 
 class ModelInterface:
     def __init__(self, config):
@@ -65,6 +66,24 @@ class ModelInterface:
                 'num_queries': 1,
                 'camera_names': self.config['camera_names'],
             }
+        elif self.config['policy_class'] == 'DDT':
+            self.config['policy_config'] = {
+                'lr': self.config['lr'],
+                'lr_backbone': self.config['lr_backbone'],
+                'backbone': self.config.get('backbone', 'dino_v2'),
+                'num_queries': self.config['chunk_size'],
+                'hidden_dim': self.config['hidden_dim'],
+                'nheads': self.config['nheads'],
+                'enc_layers': self.config['enc_layers'],
+                'state_dim': self.config.get('state_dim', 16),
+                'action_dim': self.config.get('action_dim', 16),
+                'camera_names': self.config['camera_names'],
+                'qpos_noise_std': self.config.get('qpos_noise_std', 0),
+                # DDT 特有参数
+                'num_blocks': self.config.get('num_blocks', 12),
+                'mlp_ratio': self.config.get('mlp_ratio', 4.0),
+                'num_inference_steps': self.config.get('num_inference_steps', 10),
+            }
         else:
             raise NotImplementedError
 
@@ -75,6 +94,8 @@ class ModelInterface:
             return ACTTVPolicy(self.config['policy_config'])
         elif self.config['policy_class'] == 'CNNMLP':
             return CNNMLPPolicy(self.config['policy_config'])
+        elif self.config['policy_class'] == 'DDT':
+            return DDTPolicy(self.config['policy_config'])
         else:
             raise NotImplementedError