# Unitree G1 CSV、MT 与 Isaac 数据格式

本文档定义本仓库转换脚本使用的输入 CSV，以及输出的 MT 和 Isaac NPZ 格式。

## 通用约定

- `T`：输出动作的帧数。
- 位置：米（m）。
- 关节角：弧度（rad）。
- 线速度：米每秒（m/s）。
- 角速度：弧度每秒（rad/s）。
- 时序浮点字段：`float32`。
- `fps`：形状 `(1,)` 的 `int64` 数组。
- 输出帧数：`max(1, round(T_source × target_fps / source_fps))`。
- 位置与关节角使用线性插值，四元数使用 SLERP。

坐标轴方向由用户提供的 G1 MJCF 模型决定。

## 输入 CSV

每行表示一帧。CSV 通常包含 `Frame`，转换必需的是根节点和 29 个
关节字段：

```text
Frame              # 可选，不参与时间计算
root_translateX
root_translateY
root_translateZ
root_rotateX
root_rotateY
root_rotateZ
{joint_name}_dof  # 29 列
```

输入约定：

| 内容 | 单位/表示 |
|---|---|
| `root_translate*` | 厘米 |
| `root_rotate*` | XYZ 欧拉角，度 |
| `*_dof` | 关节角，度 |

CSV 的 29 个 DOF 使用以下 MT 顺序：

```python
MT_JOINT_NAMES = [
    "left_hip_pitch_joint", "left_hip_roll_joint", "left_hip_yaw_joint",
    "left_knee_joint", "left_ankle_pitch_joint", "left_ankle_roll_joint",
    "right_hip_pitch_joint", "right_hip_roll_joint", "right_hip_yaw_joint",
    "right_knee_joint", "right_ankle_pitch_joint", "right_ankle_roll_joint",
    "waist_yaw_joint", "waist_roll_joint", "waist_pitch_joint",
    "left_shoulder_pitch_joint", "left_shoulder_roll_joint",
    "left_shoulder_yaw_joint", "left_elbow_joint",
    "left_wrist_roll_joint", "left_wrist_pitch_joint",
    "left_wrist_yaw_joint",
    "right_shoulder_pitch_joint", "right_shoulder_roll_joint",
    "right_shoulder_yaw_joint", "right_elbow_joint",
    "right_wrist_roll_joint", "right_wrist_pitch_joint",
    "right_wrist_yaw_joint",
]
```

时间间隔由 `--source-fps` 指定。

## MT NPZ

| 字段 | 形状 | 类型 | 含义 |
|---|---:|---|---|
| `root_pos` | `(T, 3)` | `float32` | 根节点世界坐标位置 |
| `root_rot` | `(T, 4)` | `float32` | 根节点世界坐标四元数，`xyzw` |
| `dof_pos` | `(T, 29)` | `float32` | MT 顺序的关节角 |
| `local_body_pos` | `(T, 27, 3)` | `float32` | 根坐标系下的刚体位置 |
| `joint_names` | `(29,)` | Unicode | `dof_pos` 的关节名称 |
| `body_names` | `(27,)` | Unicode | `local_body_pos` 的刚体名称 |
| `fps` | `(1,)` | `int64` | 输出帧率 |

局部刚体位置定义：

```text
local_body_pos = inverse(root_rot) · (body_pos_w - root_pos)
```

MT 刚体顺序：

```python
MT_BODY_NAMES = [
    "pelvis",
    "left_hip_pitch_link", "left_hip_roll_link", "left_hip_yaw_link",
    "left_knee_link", "left_ankle_pitch_link", "left_ankle_roll_link",
    "right_hip_pitch_link", "right_hip_roll_link", "right_hip_yaw_link",
    "right_knee_link", "right_ankle_pitch_link", "right_ankle_roll_link",
    "torso_link",
    "left_shoulder_pitch_link", "left_shoulder_roll_link",
    "left_shoulder_yaw_link", "left_elbow_link", "left_wrist_roll_link",
    "right_shoulder_pitch_link", "right_shoulder_roll_link",
    "right_shoulder_yaw_link", "right_elbow_link", "right_wrist_roll_link",
    "head_mimic", "left_hand_mimic", "right_hand_mimic",
]
```

当前实现使用以下近似：

- `head_mimic` 复制 `torso_link` 的位置；
- `left_hand_mimic` 复制 `left_wrist_roll_link` 的位置；
- `right_hand_mimic` 复制 `right_wrist_roll_link` 的位置。

## Isaac NPZ

| 字段 | 形状 | 类型 | 含义 |
|---|---:|---|---|
| `fps` | `(1,)` | `int64` | 输出帧率 |
| `joint_pos` | `(T, 29)` | `float32` | Isaac 顺序的关节角 |
| `joint_vel` | `(T, 29)` | `float32` | Isaac 顺序的关节角速度 |
| `body_pos_w` | `(T, 30, 3)` | `float32` | 刚体世界坐标位置 |
| `body_quat_w` | `(T, 30, 4)` | `float32` | 刚体世界坐标四元数，`wxyz` |
| `body_lin_vel_w` | `(T, 30, 3)` | `float32` | 刚体世界坐标线速度 |
| `body_ang_vel_w` | `(T, 30, 3)` | `float32` | 刚体世界坐标角速度 |

Isaac 关节顺序：

```python
ISAAC_JOINT_NAMES = [
    "left_hip_pitch_joint", "right_hip_pitch_joint", "waist_yaw_joint",
    "left_hip_roll_joint", "right_hip_roll_joint", "waist_roll_joint",
    "left_hip_yaw_joint", "right_hip_yaw_joint", "waist_pitch_joint",
    "left_knee_joint", "right_knee_joint",
    "left_shoulder_pitch_joint", "right_shoulder_pitch_joint",
    "left_ankle_pitch_joint", "right_ankle_pitch_joint",
    "left_shoulder_roll_joint", "right_shoulder_roll_joint",
    "left_ankle_roll_joint", "right_ankle_roll_joint",
    "left_shoulder_yaw_joint", "right_shoulder_yaw_joint",
    "left_elbow_joint", "right_elbow_joint",
    "left_wrist_roll_joint", "right_wrist_roll_joint",
    "left_wrist_pitch_joint", "right_wrist_pitch_joint",
    "left_wrist_yaw_joint", "right_wrist_yaw_joint",
]
```

Isaac 刚体顺序：

```python
ISAAC_BODY_NAMES = [
    "pelvis",
    "left_hip_pitch_link", "right_hip_pitch_link", "pelvis_contour_link",
    "left_hip_roll_link", "right_hip_roll_link", "waist_roll_link",
    "left_hip_yaw_link", "right_hip_yaw_link", "torso_link",
    "left_knee_link", "right_knee_link",
    "left_shoulder_pitch_link", "right_shoulder_pitch_link",
    "left_ankle_pitch_link", "right_ankle_pitch_link",
    "left_shoulder_roll_link", "right_shoulder_roll_link",
    "left_ankle_roll_link", "right_ankle_roll_link",
    "left_shoulder_yaw_link", "right_shoulder_yaw_link",
    "left_elbow_link", "right_elbow_link",
    "left_wrist_roll_link", "right_wrist_roll_link",
    "left_wrist_pitch_link", "right_wrist_pitch_link",
    "left_wrist_yaw_link", "right_wrist_yaw_link",
]
```

根节点为刚体索引 `0`：

```python
root_pos_w = data["body_pos_w"][:, 0]
root_quat_wxyz = data["body_quat_w"][:, 0]
```

`pelvis_contour_link` 在当前实现中复制 `pelvis` 的状态。Isaac NPZ 不保存名称数组，读取方必须使用上述固定顺序。

## MT 与 Isaac 的差异

| 项目 | MT | Isaac |
|---|---|---|
| 关节角字段 | `dof_pos` | `joint_pos` |
| 关节顺序 | 按肢体分组 | 左右交替 |
| 根四元数 | `root_rot`，`xyzw` | `body_quat_w[:, 0]`，`wxyz` |
| 刚体位置 | 根节点局部坐标 | 世界坐标 |
| 刚体数量 | 27 | 30 |
| 速度 | 不保存 | 保存 |
| 名称数组 | 保存 | 不保存 |

四元数重排：

```python
# wxyz -> xyzw
quat_xyzw = quat_wxyz[..., [1, 2, 3, 0]]

# xyzw -> wxyz
quat_wxyz = quat_xyzw[..., [3, 0, 1, 2]]
```

## 加载示例

```python
import numpy as np

with np.load("motion_mt.npz", allow_pickle=False) as data:
    fps = int(data["fps"][0])
    dof_pos = data["dof_pos"]
    root_rot_xyzw = data["root_rot"]

with np.load("motion_isaac.npz", allow_pickle=False) as data:
    fps = int(data["fps"][0])
    joint_pos = data["joint_pos"]
    root_quat_wxyz = data["body_quat_w"][:, 0]
```