Lss arm not responding to planned actions in rViz

luricl · September 18, 2024, 3:12pm

I have migrated the lss arm project to the Humble ROS distro by making a branch from the Iron branch.

As long as I’ve tested, the migration seems to work ok, but I’ve ben struggling with this error:

[ruby $(which ign) gazebo-1] [INFO] [1726670562.952811619] [gripper_action_controller]: Received & accepted new action goal
[move_group-4] [WARN] [1726670563.196120306] [moveit_ros.planning_scene_monitor.planning_scene_monitor]: The complete state of the robot is not yet known.  Missing lss_arm_joint_7
[move_group-4] [WARN] [1726670563.503996269] [moveit.simple_controller_manager.gripper_controller_handle]: waitForExecution timed out
[move_group-4] [ERROR] [1726670563.504074549] [moveit_ros.trajectory_execution_manager]: Controller is taking too long to execute trajectory (the expected upper bound for the trajectory execution was 0.500000 seconds). Stopping trajectory.
[ruby $(which ign) gazebo-1] [INFO] [1726670563.504479900] [gripper_action_controller]: Got request to cancel goal
[ruby $(which ign) gazebo-1] [INFO] [1726670563.504519465] [gripper_action_controller]: Canceling active action goal because cancel callback received.
[rviz2-5] [ERROR] [1726670563.515105415] [move_group_interface]: MoveGroupInterface::move() failed or timeout reached

The steps to replicate it are:

setup and build the project as described in the readme
generate a 5dof arm sdf file
launch the gazebo and rViz with the following command:

ros2 launch lss_arm_moveit sim_arm_control.launch.py dof:=5

use rViz to plan some action, execute it and look at the logs

cbenson · September 19, 2024, 7:34pm

@luricl Apologies in advance for the delay - the lead designer for the ROS library is working on a priority project.

luricl · September 20, 2024, 12:23pm

Sorry, but I think I didn’t really understand what you mean

geraldinebc15 · September 20, 2024, 8:28pm

Hello @luricl

Sorry for the delay.

The issue seems to be with the “lss_arm_joint_7” which is the second finger, the difference with the rest of the joints is that one mimics the other finger (joint_6). The reason for that is that in the real arm the fingers are actuated with the same motor so it didn’t make sense to add a controller for a joint that does not exist. In Galactic the mimic joint worked just fine with the simulation, but for Humble caused issues so I removed it, but seems like that has caused other issues.

github.com

Lynxmotion/LSS-ROS2-Arms/blob/iron/lss_arm_description/urdf/lss_gripper_4dof.xacro#L138


      
              link_name="${prefix}${link_finger_1_name}"
              mesh="${finger_l_mesh}"
              collision="${collision}"
              mu="${link_finger_1_mu}"
              mesh_offset_rpy="${link_finger_1_mesh_offset}"
              />
          
          
<!-- mimic_joint="${prefix}${joint_finger_1_name}" -->
          
          
    <!-- Finger 2 -->
              <xacro:lss_arm_joint_
              parent="${prefix}${link_4_name}"
              child="${prefix}${link_finger_2_name}"
              joint_name="${prefix}${joint_finger_2_name}"
              joint_type="${joint_finger_2_type}"
              joint_origin_xyz="${joint_finger_2_origin_xyz}"
              joint_origin_rpy="${joint_finger_2_origin_rpy}"
              joint_axis_xyz="${joint_finger_2_axis_xyz}"
              joint_lower_limit="${joint_finger_2_lower_limit}"
              joint_upper_limit="${joint_finger_2_upper_limit}"
              joint_velocity_limit="${joint_finger_2_velocity_limit}"

github.com

Lynxmotion/LSS-ROS2-Arms/blob/master/lss_arm_description/urdf/lss_gripper_4dof.xacro#L136


      
          />
          <xacro:lss_arm_link
          link_name="${prefix}${link_finger_1_name}"
          mesh="${finger_l_mesh}"
          collision="${collision}"
          mu="${link_finger_1_mu}"
          mesh_offset_rpy="${link_finger_1_mesh_offset}"
          />
          
          
<!-- Finger 2 -->
          <xacro:lss_arm_joint_
          parent="${prefix}${link_4_name}"
          child="${prefix}${link_finger_2_name}"
          joint_name="${prefix}${joint_finger_2_name}"
          joint_type="${joint_finger_2_type}"
          joint_origin_xyz="${joint_finger_2_origin_xyz}"
          joint_origin_rpy="${joint_finger_2_origin_rpy}"
          joint_axis_xyz="${joint_finger_2_axis_xyz}"
          joint_lower_limit="${joint_finger_2_lower_limit}"
          joint_upper_limit="${joint_finger_2_upper_limit}"
          joint_velocity_limit="${joint_finger_2_velocity_limit}"

Not sure if this might be related but in case it helps:

luricl · September 25, 2024, 12:25pm

Hi @geraldinebc15! Thanks for your reply!

I still haven’t been able to use the full arm due to a problem in the gripper_action_controller, wich makes the gripper to be unable to use. I’ve described the problem better in here

luricl · October 23, 2024, 1:36pm

I think I’ve found a way to make it work: I plan and execute some motions with the arm until the grippers start to work.

As long as I’ve tested, this works fine. But I still haven’t discovered why