UR5 initial pose is shown incorrectly in gazebo. Why?

asked 2020-05-12 12:41:44 -0600

Pinknoise2077 gravatar image

updated 2020-05-12 13:25:33 -0600

Hi All,

I have been playing with the UR5 robot in gazebo/ROS for a while now, and most of the time the initial pose that I set in my launch file is set correctly/displayed correctly in gazebo. However, sometimes the initial pose (shown in the code example below) that I've calculated using the ur_kinematics inverse function is incorrect.

For example:

  <node name="spawn_gazebo_model" pkg="gazebo_ros" type="spawn_model" args="-urdf -param robot_description 
  -J shoulder_pan_joint 0.350042
  -J shoulder_lift_joint 4.11583
  -J elbow_joint  5.21853
  -J wrist_1_joint 0.0902968
  -J wrist_2_joint 0.435357
  -J wrist_3_joint 0.000113458
  -model robot" respawn="false" output="screen" />

I've also tried in another software to validate, and everything seems fine. Here is the difference between the roboDK and gazebo representation of the same robot configuration (same joint angles).

robodk

image description

Am I doing something wrong? Is there a bug in gazebo?

Thanks!

edit: I've checked the joint limits and unfortunately that is not the issue. Even with -2pi to 2pi it doesn't give the correct robot configuration. Interestingly, if I flip joint 3 by 2pi ( -J elbow_joint -1.06465530718), it works.

edit retag flag offensive close merge delete
add a comment