Getting Started with Pinocchio and MeshCat for reBot Arm B601-DM

traj_sim_geodesic

6-DOF Robotic Arm · Multi-Motor Support · Kinematics Solver · Trajectory Planning · Fully Open Source

📖 Introduction

reBotArm Control is a Python control library for the reBot Arm B601 robotic arm, providing a complete solution from low-level motor control to high-level kinematics computation.

✨ Core Features

🦾 Dual Model Support — B601-DM (Damiao motors) and B601-RS (RobStride motors)
🧮 Kinematics Solver — Forward/Inverse kinematics based on Pinocchio
🛤️ Trajectory Planning — SE(3) geodesic trajectory + CLIK tracking
🔧 Flexible Configuration — YAML configuration file for quick hardware adaptation

⚙️ Quick Start

Requirements

Item	Requirement
Python	3.10+
Operating System	Ubuntu 22.04+
Communication Interface	USB2CAN Serial Bridge or CAN Interface

Installation Steps

Step 1. Install uv (if not installed)

curl -LsSf https://astral.sh/uv/install.sh | sh

Step 2. Sync Environment (Install All Dependencies)

git clone https://github.com/vectorBH6/reBotArm_control_py.git
cd reBotArm_control_py
uv sync

tip

uv sync will automatically create a virtual environment (if it doesn't exist) and install all dependencies according to pyproject.toml and uv.lock.

🔌 Hardware Configuration

Default: Damiao USB2CAN Serial Bridge

reBot Arm B601-DM uses the Damiao USB2CAN serial bridge module by default.

Hardware Connection:

Connect the USB2CAN module to your computer via USB cable
The system will automatically recognize it as /dev/ttyACM0 device

Configuration Verification:

# Check device
ls /dev/ttyACM0

# Scan motors
motorbridge-cli scan --vendor damiao --transport dm-serial \
    --serial-port /dev/ttyACM0 --serial-baud 921600

Optional: Standard CAN Interface

Using other USB-CAN adapters (CANable, PCAN, etc.):

# Start CAN interface
sudo ip link set can0 up type can bitrate 500000

# Verify interface
ip -details link show can0

Motor Brand Configuration

Motor Brand	Transmission	Configuration	Baud Rate
Damiao	Serial Bridge	`dm-serial`	921600
Damiao	CAN Interface	`socketcan`	500000
RobStride	CAN Interface	`socketcan`	500000

tip

For Damiao motors using serial bridge, must set --transport dm-serial
Feedback ID rule: feedback_id = motor_id + 0x10

📁 Project Structure

reBotArm_control_py/
├── config/                     # Configuration files
│   └── robot.yaml              # Joint parameter configuration
├── example/                    # Example programs
│   ├── Debug Tools/
│   │   ├── 1_damiao_text.py        # Single motor console
│   │   └── 2_zero_and_read.py      # Zero calibration
│   ├── Kinematics Tests/
│   │   ├── 5_fk_test.py            # Forward kinematics
│   │   └── 6_ik_test.py            # Inverse kinematics
│   ├── Real Machine Control/
│   │   ├── 7_arm_ik_control.py     # IK real-time control
│   │   ├── 8_arm_traj_control.py   # Trajectory planning
│   │   └── 9_gravity_compensation.py  # Gravity compensation
│   └── sim/                    # Simulation tools
├── reBotArm_control_py/        # Core library
│   ├── actuator/               # Actuator module
│   ├── kinematics/             # Kinematics module
│   ├── controllers/            # Controller module
│   └── trajectory/             # Trajectory planning module
├── urdf/                       # URDF model
└── README.md

🎮 Example Programs

Debug Tools

1️⃣ Single Motor Console (`1_damiao_text.py`)

Direct motorbridge SDK single motor testing with three control modes.

Usage:

uv run python example/1_damiao_text.py

Interactive Commands:

Command	Description
`mit <pos_deg> [vel kp kd tau]`	MIT mode
`posvel <pos_deg> [vlim]`	POS_VEL mode
`vel <vel_rad_s>`	Velocity mode
`enable` / `disable`	Enable/Disable
`set_zero`	Set zero position
`state`	View state

2️⃣ Zero Calibration & Angle Monitor (`2_zero_and_read.py`)

Automatically set all joint zeros and display joint angles in real-time.

Usage:

uv run python example/2_zero_and_read.py

Kinematics Tests

5️⃣ Forward Kinematics Test (`5_fk_test.py`)

Calculate end-effector pose from joint angles.

Input: 6 joint angles (degrees)

Output:

End-effector position (X, Y, Z) — Unit: meters
Rotation matrix (3×3)
Euler angles (Roll/Pitch/Yaw) — Unit: degrees

Example:

uv run python example/5_fk_test.py
> 0 0 0 0 0 0
> 45 -30 15 -60 90 180

6️⃣ Inverse Kinematics Test (`6_ik_test.py`)

Solve joint angles from desired end-effector pose.

Input Format:

Position only: <x> <y> <z> (meters)
Position + Orientation: <x> <y> <z> <roll> <pitch> <yaw> (degrees)

Example:

uv run python example/6_ik_test.py
> 0.25 0.0 0.15              # Position only
> 0.25 0.0 0.15 0 0 0        # Position + Orientation

Real Machine Control

Permission Setup

Before running real machine control examples, you need to set device permissions:

# Set serial device permission (Damiao USB2CAN)
sudo chmod 666 /dev/ttyACM0

# Or for CAN interface (e.g., can0)
sudo chmod 666 /dev/can0

7️⃣ IK Real-time Control (`7_arm_ik_control.py`)

Real-time end-effector control based on IK solver.

Interactive Commands:

Command	Description
`x y z [roll pitch yaw]`	Target end-effector pose
`state`	View current/target state
`pos`	Current end-effector position
`q/quit/exit`	Quit

Usage:

uv run python example/7_arm_ik_control.py
> 0.3 0.0 0.2
> 0.3 0.1 0.25 0 0.5 0

8️⃣ Trajectory Planning Control (`8_arm_traj_control.py`)

SE(3) geodesic trajectory planning + CLIK tracking.

Input Format:

x y z [roll pitch yaw] [duration]

Parameters:

x, y, z: Target position (meters)
roll, pitch, yaw: Target orientation (radians)
duration: Movement duration (seconds), default 2.0s

Usage:

uv run python example/8_arm_traj_control.py
> 0.3 0.0 0.3 0 0.4 0 2.0

9️⃣ Gravity Compensation Control (`9_gravity_compensation.py`)

Compensates for joint gravity using Pinocchio dynamics model.

Control Law:

tau = g(q)          — Gravity feedforward
pos = current motor position  — Joint position follows current position
kp = 2,  kd = 1     — Unified stiffness/damping for all motors

Expected Behavior:

The robotic arm can "float" in any posture
Won't fall due to its own weight when released
Can be manually moved to any position

Usage:

uv run python example/9_gravity_compensation.py

Output:

Real-time display of expected torque for each joint (N·m)
Press Ctrl+C to stop and disconnect

📄 License

This project is open source under the MIT License.

☎ Contact Us

Technical Support: Submit Issue
Repository: GitHub

🌟 If this project helps you, please give us a Star!

📖 Introduction​

✨ Core Features​

⚙️ Quick Start​

Requirements​

Installation Steps​

Step 1. Install uv (if not installed)​

Step 2. Sync Environment (Install All Dependencies)​

🔌 Hardware Configuration​

Default: Damiao USB2CAN Serial Bridge​

Optional: Standard CAN Interface​

Motor Brand Configuration​

📁 Project Structure​

🎮 Example Programs​

Debug Tools​

1️⃣ Single Motor Console (1_damiao_text.py)​

2️⃣ Zero Calibration & Angle Monitor (2_zero_and_read.py)​

Kinematics Tests​

5️⃣ Forward Kinematics Test (5_fk_test.py)​

6️⃣ Inverse Kinematics Test (6_ik_test.py)​

Real Machine Control​

7️⃣ IK Real-time Control (7_arm_ik_control.py)​

8️⃣ Trajectory Planning Control (8_arm_traj_control.py)​

9️⃣ Gravity Compensation Control (9_gravity_compensation.py)​

📄 License​

☎ Contact Us​

📖 Introduction

✨ Core Features

⚙️ Quick Start

Requirements

Installation Steps

Step 1. Install uv (if not installed)

Step 2. Sync Environment (Install All Dependencies)

🔌 Hardware Configuration

Default: Damiao USB2CAN Serial Bridge

Optional: Standard CAN Interface

Motor Brand Configuration

📁 Project Structure

🎮 Example Programs

Debug Tools

1️⃣ Single Motor Console (`1_damiao_text.py`)

2️⃣ Zero Calibration & Angle Monitor (`2_zero_and_read.py`)

Kinematics Tests

5️⃣ Forward Kinematics Test (`5_fk_test.py`)

6️⃣ Inverse Kinematics Test (`6_ik_test.py`)

Real Machine Control

7️⃣ IK Real-time Control (`7_arm_ik_control.py`)

8️⃣ Trajectory Planning Control (`8_arm_traj_control.py`)

9️⃣ Gravity Compensation Control (`9_gravity_compensation.py`)

📄 License

☎ Contact Us