ROS2 for just the servo

vjmn · May 6, 2024, 5:21am

I have the 4dof arm (for which you’d helped me with the ROS2 setup). I am now reconfiguring some of the servos for other purposes.

Was wondering if you had the ROS2 definitions for just 1 servo. Want to use that to build up the set differently.

Regards

geraldinebc15 · May 7, 2024, 1:15pm

Hello @vjmn

I don’t have an example for just for one servo but this launch has a setup for two servos:

github.com

Lynxmotion/LSS-ROS2-Control/blob/main/launch/lss_hw_example.launch.py

# Copyright 2020 ROS2-Control Development Team (2020)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import os

from ament_index_python.packages import get_package_share_directory

from launch import LaunchDescription
from launch_ros.actions import Node

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This file is related to that setup:

github.com

Lynxmotion/LSS-ROS2-Control/blob/main/config/ros2_lss_bus.yaml

controller_manager:
  ros__parameters:
    update_rate: 100  # Hz
    diagnostic_period: 1

    effort_controller:
      type: forward_command_controller/ForwardCommandController

    joint_state_broadcaster:
      type: joint_state_broadcaster/JointStateBroadcaster

    position_trajectory_controller:
      type: joint_trajectory_controller/JointTrajectoryController

effort_controller:
  ros__parameters:
    joints:
      - J0
      - J5
    interface_name: effort

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The joints used for that example are:
- J0
- J5
Which are the servos with IDs 0 and 5

These are also used for that example, as you can see it uses an RRbot (rotational, rotational configuration)

github.com

Lynxmotion/LSS-ROS2-Control/blob/main/urdf/ros2_lss_bus.urdf.xacro

<?xml version="1.0"?>
<!-- Revolute-Revolute Manipulator -->
<!--
Copied and modified from ROS1 example:
https://github.com/ros-simulation/gazebo_ros_demos/blob/kinetic-devel/rrbot_description/urdf/rrbot.xacro

Adapted to Lynxmotion LSS Hardware, for original rrbot ros2 controls example see:
https://github.com/ros-controls/ros2_control_demos
-->
<robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="2dof_robot">

  <!-- Import RRBot macro -->
  <xacro:include filename="rrbot/rrbot.urdf.xacro" />
  <!-- <xacro:include filename="$(find ros2_control_demo_robot)/description/rrbot/rrbot.urdf.xacro" /> -->

  <!-- Import all Gazebo-customization elements, including Gazebo colors -->
  <xacro:include filename="rrbot/rrbot.gazebo.xacro" />
  <!-- <xacro:include filename="$(find ros2_control_demo_robot)/description/rrbot/rrbot.gazebo.xacro" /> -->

  <!-- Import Rviz colors -->

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I hope that helps!

vjmn · May 11, 2024, 5:12am

@geraldinebc15
Thanks a lot for this