Package dynamixel_control

The ros2_control implementation for any kind of ROBOTIS Dynamixel robots.

• dynamixel_hardware: the SystemInterface implementation for the multiple ROBOTIS Dynamixel servos.
• open_manipulator_x_description: the reference implementation of the ros2_control robot using ROBOTIS OpenManipulator-X.

The dynamixel_hardware package is hopefully compatible any configuration of ROBOTIS Dynamixel servos thanks to the ros2_control's flexible architecture.

This fork allows to use dynamixel_hardware package with dynamixels that use communication protocol version 1.0

At this moment fork supports only position control and only with ros-foxy.

Set up

First install ROS 2 Foxy on Ubuntu 20.04. Then follow the instruction below.

$ source /opt/ros/foxy/setup.bash
$ mkdir -p ~/ros/foxy && cd ~/ros/foxy
$ git clone https://github.com/Wiktor-99/dynamixel_hardware.git src
$ vcs import src < src/dynamixel_control.repos
$ rosdep install --from-paths src --ignore-src -r -y
$ colcon build --symlink-install --cmake-args -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
$ . install/setup.bash

Configuration of dynamixel_control in robot description

To use dynamixel_control add following ros2_control block.

<ros2_control name="${name}" type="system">
  <hardware>
    <plugin>dynamixel_hardware/DynamixelHardware</plugin>
    <param name="usb_port">/dev/ttyUSB0</param>
    <param name="baud_rate">57600</param>
    <param name="joint_ids">1,2,3</param>
    <param name="use_stub">true</param> <!-- optional parameter -->
  </hardware>
  <joint name="joint_name">
  </joint>
</ros2_control>

It is necessary to set following parameters: usb_port, baud_rate and joint_ids. Use stub is optional parameter if used commands will not forwarded to hardware.

Also joint blocks inside of ros2_control should be used. Example of joint block:

  <joint name="id_1">
    <param name="id">1</param>
    <param name="position_multiplier">position_multiplier[double]</param>
    <param name="id_of_joint_to_mimic">id_of_existing_joint_to_mimic[int]</param>
    <param name="Return_Delay_Time">0</param>
    <param name="CW_Angle_Limit">0</param>
    <param name="CCW_Angle_Limit">1023</param>
    <param name="Moving_Speed">1023</param>
    <command_interface name="position" />
    <state_interface name="position" />
    <state_interface name="velocity" />
    <state_interface name="effort" />
  </joint>

Remember to configure ros2_control package with joint_trajectory controller!!

Usage

When package is configured and you have launched both package with description of your robot and ros2_control you can move your robot using following command: .

$ ros2 action send_goal /joint_trajectory_controller/follow_joint_trajectory control_msgs/action/FollowJointTrajectory -f "{
  trajectory: {
    joint_names: [name_of_first_joint, ..., name_of_last_joint],
    points: [
      { positions: [0.1, ..., 0], time_from_start: { sec: 2 } },
      { positions: [-0.1, ..., 0], time_from_start: { sec: 4 } },
      { positions: [0, ..., 0], time_from_start: { sec: 6 } }
    ]
  }
}"