Record And Playback

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Overview

Imagine that you would like to have the robot arm perform some motions to achieve a specific task. One way of doing this would be to create a JointTrajectory of desired joint positions at specific times which you could then command the robot. Alternatively (and much less time consuming), you could manually manipulate the arm to do the specific motions and record them in a ROS bag file. Then, you could ‘play back’ the bag file as many times as you like to repeat the motions on the same robot later. This ‘record/playback’ feature is made possible by the xsarm_puppet_single.

Structure

As shown below, the interbotix_xsarm_puppet package builds on top of the interbotix_xsarm_control package. To get familiar with that package, please look at its README. The nodes specific to this package are described below.

The above diagram shows the structure for the ‘record/playback’ feature. The two nodes involved are:

• xsarm_puppet_single - responsible for reading the arm’s current joint states and publishing them as position commands to the /<robot_name>/commands/joint_group and /<robot_name>/commands/joint_single topics. Conveniently, as the arm is torqued off so that the user can manipulate it, the joints will not act upon these commands
• record - responsible for recording the two topics mentioned above in a bag file so that they can be played back later
• play - responsible for playing back the bag file mentioned above with the arm in a torqued on state; the playback is delayed 3 seconds to give time for the xs_sdk node to load

Usage

To record joint commands while manipulating a single robot (let’s say the PincherX-150), type the following in a terminal:

$ ros2 launch interbotix_xsarm_puppet xsarm_puppet_single.launch.py robot_model:=px150 record_or_playback:=record

Once the nodes finish launching, manually manipulate the arm and gripper through your desired motions. When done, return the robot to its initial starting position and Ctrl + C the nodes so that rosbag stops recording. By default, the bag file will be saved in the bag directory. To playback the motion, type the following in the terminal:

$ ros2 launch interbotix_xsarm_puppet xsarm_puppet_single.launch.py robot_model:=px150 record_or_playback:=playback

If you specified a custom bag file name, make sure to include the name in the above command as well. When the bag file finishes playing, you can restart it by navigating to the directory where the bag file is located and in a terminal, type:

$ ros2 bag play </path/to/bag>

The robot should now repeat the motions. When done, Ctrl + C to stop all nodes. To see other command line arguments for the ‘xsarm_puppet_single.launch.py’ file, refer to the table below.

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, aloha_wx250s, aloha_vx300s
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.	true	true, false
record_or_playback	‘record’ to record joint commands while physically manipulating the arm to a bagfile or ‘playback’ to play-back joint commands from a bagfile to a torqued on arm.		record, playback
bag_name	Desired ROS bag file name.	LaunchConfig(robot_name) + ‘_commands’
launch_driver	true if xsarm_control should be launched - set to false if you would like to run your own version of this file separately.	true	true, false
xs_driver_logging_level	set the logging level of the X-Series Driver.	INFO	DEBUG, INFO, WARN, ERROR, FATAL
use_sim	if true, the DYNAMIXEL simulator node is run; use RViz to visualize the robot’s motion; if false, the real DYNAMIXEL driver node is run.	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; 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; 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; 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; 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 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 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) + ‘ ‘)