ROS 2 Controllers Configuration

Overview

This package provides the necessary ROS controllers needed to get MoveIt to control any physical Interbotix X-Series arm. It essentially takes in Joint Trajectory commands from MoveIt (via the FollowJointTrajectoryAction interface) and then publishes joint commands at the right time to the xs_sdk node. Currently, only the ‘position’ values in the Joint Trajectory messages are used since that provides the smoothest motion. Note that while this package is really only meant to be used with MoveIt, it could technically be used with any other node that can interface properly with the joint_trajectory_controller package.

Structure

../_images/xsarm_ros_control_flowchart_ros2.png

As explained in the Overview, this package builds on top of the interbotix_xsarm_control package (which starts the xs_sdk node), and is typically used in conjunction with the interbotix_xsarm_moveit package. To get familiar with the nodes in those packages, feel free to look at their documentation. The other nodes are described below:

controller_manager - responsible for loading and starting a set of controllers at once, as well as automatically stopping and unloading those same controllers
spawner - responsible for spawning each controller; in this case, three spawners are loaded, one for the arm_controller, one for the gripper_controller, and if using fake hardware, one for a joint_state_broadcaster
xs_hardware_interface - receives joint commands from the ROS controllers and publishes them to the correct topics (subscribed to by the xs_sdk node) at the appropriate times

Usage

This package is not meant to be used by itself but included in a launch file within your custom ROS package (which should expose a FollowJointTrajectoryAction interface).

To run this package, enter the command below in a terminal (assuming a PincherX-150 is being launched).

$ ros2 launch interbotix_xsarm_ros_control xsarm_ros_control.launch.py robot_model:=px150

This is the bare minimum needed to get up and running. Take a look at the table below to see how to further customize with other launch file arguments.

Argument	Description	Default	Choices
robot_model	model type of the Interbotix Arm such as ‘wx200’ or ‘rx150’.		`px100`, `px150`, `rx150`, `rx200`, `wx200`, `wx250`, `wx250s`, `vx250`, `vx300`, `vx300s`, `mobile_px100`, `mobile_wx200`, `mobile_wx250s`
robot_name	name of the robot (typically equal to `robot_model`, but could be anything).	LaunchConfig(`robot_model`)
use_rviz	launches RViz if set to `true`.	`false`
mode_configs	the file path to the ‘mode config’ YAML file.	LocalVar(‘FindPackageShare(pkg= `interbotix_xsarm_ros_control`) + ‘config’ + ‘modes.yaml’’)
use_sim_time	tells ROS nodes asking for time to get the Gazebo-published simulation time, published over the ROS topic /clock; this value is automatically set to `true` if using Gazebo hardware.	`false`	`true`, `false`
base_link_frame	name of the ‘root’ link on the arm; typically `base_link`, but can be changed if attaching the arm to a mobile base that already has a `base_link` frame.	`base_link`
use_gripper	if `true`, the default gripper is included in the `robot_description` parameter; if `false`, it is left out; set to `false` if not using the default gripper.	`true`	`true`, `false`
show_ar_tag	if `true`, the AR tag mount is included in the `robot_description` parameter; if `false`, it is left out; set to `true` if using the AR tag mount in your project.	`false`	`true`, `false`
show_gripper_bar	if `true`, the gripper_bar link is included in the `robot_description` parameter; if `false`, the gripper_bar and finger links are not loaded. Set to `false` if you have a custom gripper attachment.	`true`	`true`, `false`
show_gripper_fingers	if true, the gripper fingers are included in the `robot_description` parameter; if `false`, the gripper finger links are not loaded. Set to `false` if you have custom gripper fingers.	`true`	`true`, `false`
use_world_frame	set this to `true` if you would like to load a ‘world’ frame to the `robot_description` parameter which is located exactly at the ‘base_link’ frame of the robot; if using multiple robots or if you would like to attach the ‘base_link’ frame of the robot to a different frame, set this to `false`.	`true`	`true`, `false`
external_urdf_loc	the file path to the custom urdf.xacro file that you would like to include in the Interbotix robot’s urdf.xacro file.	‘’
hardware_type	configures the `robot_description` parameter to use the actual hardware, fake hardware, or hardware simulated in Gazebo.	`actual`	`actual`, `fake`, `gz_classic`
robot_description	URDF of the robot; this is typically generated by the xacro command.	Command(FindExec(`xacro`) + ‘ ‘ + LocalVar(‘FindPackageShare(pkg= `interbotix_xsarm_descriptions`) + ‘urdf’ + LaunchConfig(`robot_model`)’) + ‘.urdf.xacro ‘ + ‘robot_name:=’ + LaunchConfig(`robot_name`) + ‘ ‘ + ‘base_link_frame:=’ + LaunchConfig(`base_link_frame`) + ‘ ‘ + ‘use_gripper:=’ + LaunchConfig(`use_gripper`) + ‘ ‘ + ‘show_ar_tag:=’ + LaunchConfig(`show_ar_tag`) + ‘ ‘ + ‘show_gripper_bar:=’ + LaunchConfig(`show_gripper_bar`) + ‘ ‘ + ‘show_gripper_fingers:=’ + LaunchConfig(`show_gripper_fingers`) + ‘ ‘ + ‘use_world_frame:=’ + LaunchConfig(`use_world_frame`) + ‘ ‘ + ‘external_urdf_loc:=’ + LaunchConfig(`external_urdf_loc`) + ‘ ‘ + ‘hardware_type:=’ + LaunchConfig(`hardware_type`) + ‘ ‘)