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Real UR5 doesn't stop moving when it should

asked 2019-11-21 04:21:41 -0500

shu gravatar image

updated 2019-11-22 02:50:42 -0500

In gazebo the giving the ur5 coordinate goals is working perfectly. However, with the real ur5 there are some existing disparities with its movements.

Here are my start up commands:

roslaunch ur_modern_driver ur5_bringup.launch robot_ip:=ROBOTIP [reverse_port:=REVERSE_PORT]
roslaunch ur5_moveit_config ur5_moveit_planning_execution.launch sim:=true
roslaunch ur5_moveit_config moveit_rviz.launch config:=true

I am using the TracIK plugin for my kinematics solver. The following code is how i define the ur5 to move 0.1 meters in the y direction.

pose_goal = geometry_msgs.msg.Pose()
pose_goal.position.x = group.get_current_pose().pose.position.x;
pose_goal.position.y = group.get_current_pose().pose.position.y + 0.1;
pose_goal.position.z = group.get_current_pose().pose.position.z;
pose_goal.orientation.x = group.get_current_pose().pose.orientation.x;
pose_goal.orientation.y = group.get_current_pose().pose.orientation.y;
pose_goal.orientation.z = group.get_current_pose().pose.orientation.z;
pose_goal.orientation.w = group.get_current_pose().pose.orientation.w;

The ur5 is moving in the correct direction every time, but there's quite a lot of inaccuracy in its expected and actual end-effector positions after stopping, the largest of which I've seen is an actual y coordinate of 0.43 versus an expected y coordinate of 0.508. The disparity between the actual and expected coordinates is not the same every time.

Can someone point me in the right direction of where I should be looking to fix this issue? Please let me know if I need to post more information.

Edit - now with full planning execution log after switching to UniversalRobots/Universal_Robots_ROS_Driver:

    shu@sewts-ideapad-002:/opt/ros/kinetic/share/ur5_moveit_config/config$ roslaunch ur5_moveit_config ur5_moveit_planning_execution.launch sim:=true
... logging to /home/shu/.ros/log/0c4ff900-0c7b-11ea-abbf-98fa9b14f60a/roslaunch-sewts-ideapad-002-28607.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://sewts-ideapad-002:43151/


 * /move_group/allow_trajectory_execution: True
 * /move_group/capabilities: move_group/MoveGr...
 * /move_group/controller_list: [{'default': True...
 * /move_group/endeffector/planner_configs: ['SBLkConfigDefau...
 * /move_group/jiggle_fraction: 0.05
 * /move_group/manipulator/longest_valid_segment_fraction: 0.01
 * /move_group/manipulator/planner_configs: ['SBLkConfigDefau...
 * /move_group/max_range: 5.0
 * /move_group/max_safe_path_cost: 1
 * /move_group/moveit_controller_manager: moveit_simple_con...
 * /move_group/moveit_manage_controllers: True
 * /move_group/octomap_resolution: 0.025
 * /move_group/planner_configs/BKPIECEkConfigDefault/border_fraction: 0.9
 * /move_group/planner_configs/BKPIECEkConfigDefault/failed_expansion_score_factor: 0.5
 * /move_group/planner_configs/BKPIECEkConfigDefault/min_valid_path_fraction: 0.5
 * /move_group/planner_configs/BKPIECEkConfigDefault/range: 0.0
 * /move_group/planner_configs/BKPIECEkConfigDefault/type: geometric::BKPIECE
 * /move_group/planner_configs/ESTkConfigDefault/goal_bias: 0.05
 * /move_group/planner_configs/ESTkConfigDefault/range: 0.0
 * /move_group/planner_configs/ESTkConfigDefault/type: geometric::EST
 * /move_group/planner_configs/KPIECEkConfigDefault/border_fraction: 0.9
 * /move_group/planner_configs/KPIECEkConfigDefault/failed_expansion_score_factor: 0.5
 * /move_group/planner_configs/KPIECEkConfigDefault/goal_bias: 0.05
 * /move_group/planner_configs/KPIECEkConfigDefault/min_valid_path_fraction: 0.5
 * /move_group/planner_configs/KPIECEkConfigDefault/range: 0.0
 * /move_group/planner_configs/KPIECEkConfigDefault/type: geometric::KPIECE
 * /move_group/planner_configs/LBKPIECEkConfigDefault/border_fraction: 0.9
 * /move_group/planner_configs/LBKPIECEkConfigDefault/min_valid_path_fraction: 0.5
 * /move_group/planner_configs/LBKPIECEkConfigDefault/range: 0.0
 * /move_group/planner_configs/LBKPIECEkConfigDefault/type: geometric::LBKPIECE
 * /move_group/planner_configs/PRMkConfigDefault/max_nearest_neighbors: 10
 * /move_group/planner_configs/PRMkConfigDefault/type: geometric::PRM
 * /move_group/planner_configs/PRMstarkConfigDefault/type: geometric::PRMstar
 * /move_group/planner_configs/RRTConnectkConfigDefault/range: 0.0
 * /move_group/planner_configs/RRTConnectkConfigDefault/type: geometric::RRTCon...
 * /move_group/planner_configs/RRTkConfigDefault/goal_bias: 0.05
 * /move_group/planner_configs/RRTkConfigDefault/range: 0.0
 * /move_group/planner_configs/RRTkConfigDefault/type ...
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2 Answers

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answered 2019-11-21 09:24:00 -0500

gvdhoorn gravatar image

Please use UniversalRobots/Universal_Robots_ROS_Driver with current versions of Polyscope and CB3 or e-series controllers.

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Thank you for pointing me to the right package.

I've done the following:

1. Followed the building instructions in the Universal_robots_ROS_Driver. ur_robot_driver wasn't being recognized as a package so I put this in the ~/catkin_ws/src and rebuilt my workspace. 
2. Extracted calibration information about the UR5.
3. Changed my ur5_moveit_config/config/controllers.yaml to look for the action server /scaled_pos_traj_controller/follow_joint_trajectory
4. Launched the ur5_bringup file in ur_robot_driver with the calibration file passed in
5. roslaunch ur5_moveit_config ur5_moveit_planning_execution.launch sim:=true
6. Ran my script to try and move the robot in the y coordinate direction.

I am now getting RRTConnect: Unable to sample any valid states for goal tree as an Error message while trying to run my script. I will update the question to include the log as it's too long for the comment.

shu gravatar image shu  ( 2019-11-21 10:34:59 -0500 )edit

This should be asked in a new question.

Edit: and it has: #q338484.

gvdhoorn gravatar image gvdhoorn  ( 2019-11-25 04:00:08 -0500 )edit

answered 2019-11-21 10:54:14 -0500

duck-development gravatar image

You may try the new driver from FZI

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I've given that a try and now am getting a RRTConnect: Unable to sample any valid states for goal tree error (see my comment on the question)

shu gravatar image shu  ( 2019-11-21 10:56:47 -0500 )edit

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Asked: 2019-11-21 04:21:41 -0500

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Last updated: Nov 21 '19