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UR5KinematicsPlugin fails to plan in Cartesian space on Clearpath Husky equipped with UR5 [closed]

asked 2016-06-30 20:57:01 -0500

CMobley7 gravatar image

To Whom It May Concern,

I ran across the following ros-industrial ticket in trying to solve the inverse kinematic issue I am having.

The response to these tickets was to rewrite portions of ur_kimematic/UR5KinematicsPlugin to allow the ur5_arm to better plan and execute.

However, the main topic was RVIZ. RVIZ to the best of my knowledge is using forward kinematics due to the fact it already knows the ending joint angles. I attempted to perform inverse kinematic planning using Moveit!’s Python interface with the code below on a Clearpath Husky equiped with a UR5.

# Initialize the move group for the arm
ur5_arm = moveit_commander.MoveGroupCommander("ur5_arm")
# Get the name of the end-effector link
end_effector_link = ur5_arm.get_end_effector_link()
# Set the reference frame for pose targets
 reference_frame = "/base_link"
# Set the arm reference frame accordingly
# Allow replanning to increase the odds of a solution
# Allow some leeway in position (meters) and orientation (radians)
#Move the end effecor to the x , y, z positon
#Set the target pose in the base_link frame
target_pose = PoseStamped()
target_pose.header.frame_id = reference_frame
target_pose.header.stamp =
target_pose.pose.position.x = 1.0 #hole_pose.position.x
target_pose.pose.position.y = .1 #hole_pose.position.y
target_pose.pose.position.z = .7 #hole_pose.position.z
target_pose.pose.orientation.x = 0 #hole_pose.orientation.x
target_pose.pose.orientation.y = 0 #hole_pose.orientation.y
target_pose.pose.orientation.z = 0 #hole_pose.orientation.z
target_pose.pose.orientation.w = 1 #hole_pose.orientation.w
# Set the start state to the current state
# Set the goal pose of the end effector to the stored pose
ur5_arm.set_pose_target(target_pose, end_effector_link)
# Plan the trajectory to the goal
traj = ur5_arm.plan()
# Execute the planned trajectory
# Pause for a second

However, the code gives the following errors:

[ERROR] [1467334302.962946004, 615.710000000]: Kin chain provided in model doesn't contain standard UR joint 'shoulder_lift_joint'.
[ERROR] [1467334302.963030369, 615.710000000]: Kinematics solver of type 'ur_kinematics/UR5KinematicsPlugin' could not be initialized for group 'ur5_arm'
[ERROR] [1467334302.963234727, 615.710000000]: Kinematics solver could not be instantiated for joint group ur5_arm.
[ INFO] [1467334303.757624243, 616.500000000]: Ready to take MoveGroup commands for group ur5_arm.
[ INFO] [1467334303.757756298, 616.500000000]: Replanning: yes
[ WARN] [1467334307.237704997, 619.980000000]: Fail: ABORTED: No motion plan found. No execution attempted.

The prefix errors do not seem to affect the planner in solving forward kinematic motion problem. As I have used similar code to go to group states set in the srdf, as well as other random valid joint configurations. However, when specifying a Cartesian point, the planner always fails. After reading the posts regarding ur_kimematic/UR5KinematicsPlugin, I think the problem is more likely that my code is not using the same configuration in regards to using limited joint angles when planning and not setting ... (more)

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Closed for the following reason duplicate question by CMobley7
close date 2016-07-29 16:05:10.932704


gvdhoorn gravatar image gvdhoorn  ( 2016-07-01 02:37:48 -0500 )edit

1 Answer

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answered 2016-07-01 18:53:50 -0500

CMobley7 gravatar image

I installed trac-ik-kinematics-plugin and changed my kinematics.yaml file from

  kinematics_solver: ur_kinematics/UR5KinematicsPlugin
  kinematics_solver_search_resolution: 0.005
  kinematics_solver_timeout: 0.005
  kinematics_solver_attempts: 3


  kinematics_solver: trac_ik_kinematics_plugin/TRAC_IKKinematicsPlugin
  kinematics_solver_timeout: 0.05
  solve_type: Manipulation1

This fixed both the prefix error and has successfully solved every IK problem I have given it. So, the issue may lie in the planner.

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Asked: 2016-06-30 20:57:01 -0500

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Last updated: Jul 01 '16