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[moveit] problem about Cartesian Paths of move_group_interface

asked 2017-03-12 10:19:31 -0600

kaijianliu gravatar image

I follow tutorials in http://docs.ros.org/kinetic/api/movei...,and when i plan a Cartesian Paths for UR3, i write the following codes for UR3:

std::vector<geometry_msgs::Pose> waypoints;
  waypoints.push_back(target_pose1);

  geometry_msgs::Pose target_pose2 = target_pose1;

  target_pose2.position.z += 0.1;
  waypoints.push_back(target_pose2);  // up 
   target_pose2.position.y -= 0.1;
  waypoints.push_back(target_pose2);  // left
  target_pose2.position.z -= 0.1;
  target_pose2.position.y += 0.1;
  target_pose2.position.x -= 0.1;
  waypoints.push_back(target_pose2);  
  move_group.setMaxVelocityScalingFactor(0.1);
 moveit_msgs::RobotTrajectory trajectory;
  const double jump_threshold = 0.0;
  const double eef_step = 0.005;
  double fraction = move_group.computeCartesianPath(waypoints, eef_step, jump_threshold, trajectory);
  ROS_INFO_NAMED("tutorial", "Visualizing plan 4 (cartesian path) (%.2f%% acheived)", fraction * 100.0);
  sleep(15.0);

ROS_INFO_STREAM("cartesian path .....");
my_plan.trajectory_= trajectory;
move_group.execute(my_plan);

The problem is that the fuction double fraction = move_group.computeCartesianPath(waypoints, eef_step, jump_threshold, trajectory); seems work not well .In the terminal i got the following information:

 INFO] [1489330212.136327474]: Visualizing plan 4 (cartesian path) (0.00% acheived)
[ INFO] [1489330227.136626416]: cartesian path .....
[ WARN] [1489330227.461583608]: Skipping path because 1 points passed in.

Some problem occur when running the function for 0.00% has achieved as terminal implied. So it didn't plan out the cartesian path. soi can't see the path in rviz.

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Comments

I see that you are making tool motion increments of 0.1 m for each point which may cause some of the points to have unreachable orientation, especially in the case of an arm with a small work envelope like the UR3.

jrgnicho gravatar imagejrgnicho ( 2017-03-14 10:09:52 -0600 )edit
1

See the method description here

jrgnicho gravatar imagejrgnicho ( 2017-03-14 10:11:56 -0600 )edit

hello,I also have the same question.so you mean that the first point of the cartesian path should be the gurrent pose of the robot right? By the way how can I know whether the point I want to put in the waypoints is reachable before I fail to compute the path?

tengfei gravatar imagetengfei ( 2017-12-21 03:10:34 -0600 )edit

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answered 2017-03-14 20:20:22 -0600

kaijianliu gravatar image

I have worked out the problem. It was due to the reason that i should execute to the start point of the waypoints before i start compute cartesian. And also, I should set a longger time for compute cartesian path to ensure 100% acheved. Anyway, thanks.

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Asked: 2017-03-12 10:19:31 -0600

Seen: 1,374 times

Last updated: Mar 12 '17