How to debug PATH_TOLERANCE_VIOLATED error

[jacknlliu]

I'm debugging a issue about

[ WARN] [1508834853.402216761, 3680.601000000]: Controller arm_controller failed with error code PATH_TOLERANCE_VIOLATED
[ WARN] [1508834853.402397314, 3680.602000000]: Controller handle arm_controller reports status ABORTED
[ INFO] [1508834853.701254652, 3680.896000000]: ABORTED: Solution found but controller failed during execution

Could someone give more details about how reflect the path tolerance config from the controller/state? Is the error in controller/state equal to path tolerance?

The configuration of controller is

arm_gazebo_controller:
  type: velocity_controllers/JointTrajectoryController
  joints:
     - shoulder_pan_joint
     - shoulder_lift_joint
     - elbow_joint
     - wrist_1_joint
     - wrist_2_joint
     - wrist_3_joint
  constraints:
      goal_time: 0.6
      stopped_velocity_tolerance: 0.5
      shoulder_pan_joint: {trajectory: 0.1, goal: 0.1}
      shoulder_lift_joint: {trajectory: 0.1, goal: 0.1}
      elbow_joint: {trajectory: 0.1, goal: 0.1}
      wrist_1_joint: {trajectory: 0.1, goal: 0.1}
      wrist_2_joint: {trajectory: 0.1, goal: 0.1}
      wrist_3_joint: {trajectory: 0.1, goal: 0.1}

  gains:
      shoulder_pan_joint: {p: 1.2,  i: 0.0, d: 0.1, i_clamp: 1}
      shoulder_lift_joint: {p: 1.2,  i: 0.0, d: 0.1, i_clamp: 1}
      elbow_joint: {p: 1.2,  i: 0.0, d: 0.1, i_clamp: 1}
      wrist_1_joint: {p: 1.2,  i: 0.0, d: 0.1, i_clamp: 1}
      wrist_2_joint: {p: 1.2,  i: 0.0, d: 0.1, i_clamp: 1}
      wrist_3_joint: {p: 1.2,  i: 0.0, d: 0.1, i_clamp: 1}
  stop_trajectory_duration: 0.5
  state_publish_rate:  125
  action_monitor_rate: 10

[bmagyar]

This is an error from MoveIt. The easiest clue is the PATH_TOLERANCE_VIOLATED error code.

Check here:
http://docs.ros.org/jade/api/moveit_ros_planning_interface/html/classmoveit_1_1planning__interface_1_1MoveGroup.html#a3672b7f6c7a3f869c5a0458062117d98

[mathias-luedtke]

This is an error from MoveIt.

I would say this is an error from the trajectory controller that was reported by MoveIt.

Is the error in controller/state equal to path tolerance?

The path tolerance is the bound for the error. If it exceeds threshold the error gets reported (but the motion continues! #48).
I am not sure which path tolerance is used, as far as I could read it in the code the path tolerances of the action goal overwrite the trajectory settings in the constraints parameter.

[jacknlliu]

trajectory controller gives too less report, it's not easy to debug.

[mathias-luedtke]

trajectory controller gives too less report, it's not easy to debug.

You can set the verbose flag to get more details (#273)

[jacknlliu]

@ipa-mdl using this flag in my ros launch file, like this?

<node name="arm_gazebo_controller_spawner" pkg="controller_manager" type="controller_manager" args="verbose spawn arm_gazebo_controller" respawn="false" output="screen"/>

How to include the parameter verbose for user application?

[jacknlliu]

anyone know the details about this process?

[mathias-luedtke]

anyone know the details about this process?

You have to set it in the source code. It is just a debugging option and is not safe for real-time operation.

[jacknlliu]

@ipa-mdl I'm not sure, should I re-compile this repository?

[mathias-luedtke]

I'm not sure, should I re-compile this repository?

Clone, change verbose flag, compile.

[jacknlliu]

@ipa-mdl Thanks for your attention and very detailed reply.

[geweihgg]

Hi, @jacknlliu ,
I'm using velocity_controllers/JointTrajectoryController to control the UR5 robot in Gazebo, and encountering the same problem as you. Could you tell me how to solve it?
Thank you very very much~
GeWei

[jacknlliu]

@geweihgg I think you have met a hard problem about gazebo and ros control. We have more discusses in #303.

And could you try some workarounds following Controlling joints with velocity commands.

[geweihgg]

@jacknlliu , But I want to plan the path with MoveIt, that is to say, a JointTrajectoryController should exist. And I wonder that whether PATH_TOLERANCE_VIOLATED error is caused by imprecise PID values. Have you found any solutions for controlling UR using velocity_controllers/JointTrajectoryController?
GeWei

[jacknlliu]

@geweihgg There is a JointTrajectoryAction in joint-control-pkgs, and you can try to replace the action topics in moveit config files. Then it may work with moveit. You can follow the jaco-arm-pkgs, and this can be an example of how to use the new type position-velocity controller which included in joint-control-pkgs with moveit.

[geweihgg]

@jacknlliu , Thank you for your patience, I'll try it.
GeWei

[qboticslabs]

The Tolerance checking implemented in joint trajectory controller is mentioning in the following code.

https://github.com/ros-controls/ros_controllers/blob/kinetic-devel/joint_trajectory_controller/include/joint_trajectory_controller/tolerances.h