hexapod_control

Hexapod MPC-WBC controller adapted from legged_control based on OCS2.

NOTE: This package is still under development. Refer to it carefully.

video.mp4

Installation

Hexapod Execute Dependencies

• hexapod_robot_assets
• HexapodSoftware

OCS2

OCS2 is a huge monorepo; DO NOT try to compile the whole repo. You only need to compile ocs2_legged_robot_ros and its dependencies following the step below.

1. You are supposed to clone the OCS2, pinocchio, and hpp-fcl as described in the documentation of OCS2.

   # Clone OCS2
   git clone [email protected]:leggedrobotics/ocs2.git
   # Clone pinocchio
   git clone --recurse-submodules https://github.com/leggedrobotics/pinocchio.git
   # Clone hpp-fcl
   git clone --recurse-submodules https://github.com/leggedrobotics/hpp-fcl.git
   # Clone ocs2_robotic_assets
   git clone https://github.com/leggedrobotics/ocs2_robotic_assets.git
   # Install dependencies
   sudo apt install liburdfdom-dev liboctomap-dev libassimp-dev
   

2. Compile the ocs2_legged_robot_ros package with catkin tools instead of catkin_make. It will take you about ten minutes.

   catkin config -DCMAKE_BUILD_TYPE=RelWithDebInfo
   catkin build ocs2_legged_robot_ros ocs2_self_collision_visualization

   Ensure you can command the ANYmal as shown in the document and below.

   # Launch the example for DDP
   roslaunch ocs2_legged_robot_ros legged_robot_ddp.launch
   # OR launch the example for SQP
   roslaunch ocs2_legged_robot_ros legged_robot_sqp.launch

Build

Build the source code of legged_control by:

catkin build legged_controllers legged_unitree_description legged_hexapod_description

Build the simulation (DO NOT run on the onboard computer)

catkin build legged_gazebo

Build the hardware interface real robot. If you use your computer only for simulation, you DO NOT need to compile legged_unitree_hw (TODO: add a legged prefix to the package name)

catkin build legged_unitree_hw legged_hexapod_hw

Quick Start

1. Set your robot type as an environment variable: ROBOT_TYPE

export ROBOT_TYPE=a1
export ROBOT_TYPE=elspider_air
source ~/Documents/CodeSpace/ROS_ws/legged_ws/devel/setup.bash

2. Run the simulation:

roslaunch legged_unitree_description empty_world.launch
#roslaunch legged_hexapod_description empty_world.launch (Do not run this command)

# HexapodSoftware Simulation
source ~/Documents/CodeSpace/ROS_ws/hexapod_ws/devel/setup.bash

roslaunch user main.launch \
controller_type:=hlc \
robot_name:=elspider_air \
joystick_type:=keyboard_sim \
gazebo_hang_up:=false \
interface_type:=gazebo

Or on the robot hardware:

IMPORTANT: Hexapod is controlled by HexapodSoftware, therefore select hardware for both simulation and hardware.

roslaunch legged_unitree_hw legged_unitree_hw.launch
roslaunch legged_hexapod_hw legged_hexapod_hw.launch

1. Load the controller:

roslaunch legged_controllers load_controller.launch cheater:=false
roslaunch legged_controllers load_hexcontroller.launch cheater:=false

4. Start the legged_controller or legged_cheater_controller, NOTE that you are not allowed to start the legged_cheater_controller in real hardware!

rosservice call /controller_manager/switch_controller "start_controllers: ['controllers/legged_controller']
stop_controllers: ['']
strictness: 0
start_asap: false
timeout: 0.0"

hexapod controller

rosservice call /controller_manager/switch_controller "start_controllers: ['controllers/hexapod_controller']
stop_controllers: ['']
strictness: 0
start_asap: false
timeout: 0.0"

Or, you can start the controller using rqt_controller_manager GUI:

sudo apt install ros-noetic-rqt-controller-manager
rosrun rqt_controller_manager rqt_controller_manager

5. Set the gait in the terminal of load_controller.launch, then use RViz (you need to add what you want to display by yourself) and control the robot by cmd_vel and move_base_simple/goal:

BUG

• HexapodSoftware confilct with one of legged_control deps (ocs2/hpp-fcl/pinocchio) throw std::bad_alloc when HexapodSoftware is running.

• leg index 4 & 5 do not work properly (last 2 leg in contactNames3DoF) How to find bug: search: contactPointIndex, contactNames3DoF, numThreeDofContacts, numFeet_ PROBLEM: task.info mat R is not properly configured.

• IMU Odom is not working properly (position not updated)

TODO

• Better reference generator needed

  Subsystem: 3 out of 3
  [0]: 63,  [1]: 63,  [2]: 63,  [3]: 15,
  terminate called after throwing an instance of 'std::runtime_error'
    what():  The time of touch-down for the last swing of the EE with ID 4 is not defined.

• New Gazebo Simulation Needed

Note

• If hexapod_controller DIED, delete /tme/legged_controller to regenerate shared library.
• THE GAIT AND THE GOAL ARE COMPLETELY DIFFERENT AND SEPARATED! You don't need to type stance while the robot is lying on the ground with four foot touching the ground; it's completely wrong since the robot is already in the stance gait.
• The target_trajectories_publisher is for demonstration. You can combine the trajectory publisher and gait command into a very simple node to add gamepad and keyboard input for different gaits and torso heights and to start/stop controller (by ros service).