qm_control

Video Links: YouTube, Bilibili (for China).

Overview

qm_control is a controller for quadruped manipulators using model predictive control and whole-body control. The controller aims to make the quadruped manipulator more athletic. It has achieved tasks such as whole-body planning, end-effector motion tracking, stability with force disturbance, and whole-body compliance control. We will continue to develop more features for the controller. The project is still under development, not the final version.

Notes: Four branches focus on different tasks.

• The main branch focuses on the whole-body motion and assumes no force acting on the manipulator's end-effector.
• feature-force branch focuses on keeping stability with force disturbance acting on the manipulator's end-effector.
• feature-compliance branch focuses on whole-body compliance control.
• feature-real branch implements the controller on hardware.

Related Paper

[1] 张天霖. 基于视觉伺服与集值反馈的四足机械臂动态物体抓取研究 [D]. 哈尔滨: 哈尔滨工业大学, 2024. (for China).
Notes: 可以通过哈尔滨工业大学图书馆和深圳大学城图书馆搜索查询。

[2] T. Zhang, F. Lin, X. Peng, X. Xiong, and Y. Lou. “Whole-body Compliance Control for Quadruped Manipulator with Actuation Saturation of Joint Torque and Ground Friction”, 2024 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Accepted.

Installation

Install dependencies

• OCS2
• ROS1-Noetic

Clone and Build

# Clone
mkdir -p <catkin_ws_name>/src
cd <catkin_ws_name>/src
git clone https://github.com/skywoodsz/qm_control.git

# Build
cd <catkin_ws_name>
catkin init
catkin config -DCMAKE_BUILD_TYPE=RelWithDebInfo
catkin build

Notes: Make sure OCS2 is in the environment path.

Usage

We have two versions of the controller: MPC with WBC and only MPC.

MPC-WBC

Launch the simulation with:

mon launch qm_gazebo empty_world.launch

Load the controller:

mon launch qm_controllers load_controller.launch

Start the controller using rqt_controller_manager GUI

rosrun rqt_controller_manager rqt_controller_manager

After the manipulator is initialized, commands can be sent

# Don't use mon
roslaunch qm_controllers load_qm_target.launch 
# rviz
mon launch qm_controllers rviz.launch

MPC Only

Launch the simulation with:

mon launch qm_gazebo empty_world_mpc.launch

Load the controller:

mon launch qm_controllers load_controller_mpc.launch

Gamepad Control

You can use the gamepad to control the quadruped base and the manipulator's end-effector respectively. The schematic diagram of the gamepad is as follows:

End-effector stability testing in simulation

Analysis: The motion of the base and end-effector pose w.r.t. the initial pose when the end-effector is controlled to remain at a fixed pose during locomotion. While the base travels 30 cm, the end-effector’s deviation from its initial position is at most 3.5 mm and 2.6 degrees.

Bugs & Feature Requests

The project is still in the early stages of development and we welcome feedback. Please report bugs and request features using the Issue Tracker or Email [email protected]

TODO

• Solve the singularity problem.
• Add the foot trajectory planning.
• Merge the branch feature-real to the main.