ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question
0

Twist_controller speedl function error on robot teachpendant

asked 2021-09-09 04:01:05 -0500

horvath.daniel gravatar image

updated 2021-09-09 14:03:58 -0500

Hello! I'm currently working on a teleoperation project with an UR robot and I'm trying to use the twist_controller from the ur_robot_driver to control the robot. But I keep running intro an error whenever I try to run a command such as:

danielh@danielh:~/catkin_ws$ rostopic pub /twist_controller/command geometry_msgs/Twist "linear:
  x: 0.0
  y: 0.01
  z: 0.0
angular:
  x: 0.0
  y: 0.0
  z: 0.0"

The error is as such:

The robot cannot reach the requested pose. Script function speedl is unable to find an inverse kinematics solution.

The real robot is in a pose similar to this one:

image description

How is the function speedl related to this problem and what fix is there for this? Thanks in advance!

edit retag flag offensive close merge delete

Comments

A twist is a linear and angular velocity in a (in this case) Cartesian space.

What is the pose of your robot when you start using the twist controller?

If it's already at or near a maximum I could imagine it can't move linearly in the Y+ direction any more.

gvdhoorn gravatar image gvdhoorn  ( 2021-09-09 04:13:55 -0500 )edit

It's in a vertical pose, exactly as the one in the image from this post.

horvath.daniel gravatar image horvath.daniel  ( 2021-09-09 09:38:43 -0500 )edit

1 Answer

Sort by ยป oldest newest most voted
0

answered 2021-09-09 09:41:37 -0500

gvdhoorn gravatar image

Please add that image to this post.

re: your error: that's not going to work.

You're asking the robot to go in a straight line in a direction in which it cannot move any more (due to the pose it's currently in).

Put it in a more neutral pose, with its elbow bent, so the lower arm is parallel to the ground plane.

edit flag offensive delete link more

Comments

Alright, so indeed the problem was with the robot's pose. I moved it into a neutral pose and now it works. Thanks for the help!

horvath.daniel gravatar image horvath.daniel  ( 2021-09-10 03:33:43 -0500 )edit

Question Tools

1 follower

Stats

Asked: 2021-09-09 04:01:05 -0500

Seen: 93 times

Last updated: Sep 09 '21