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Can I use Moveit with IKFAST plugin to control a 7 DOF arm as if it is 6 DOF?

Hello, ros community,

I have a 7 DOF arm, and there is a need to control only 6 joints of it for faster planning time.

I managed to generate the IKFAST plugin for the arm (considering 6 DOF) and one joint as a free_index that can be set during planning time.

I wanted to generate a Moveit config package for the arm considering only 6 DOF as well. When setting the move group in Moveit's setup assistant, I did not add the joint to the move group.

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However, that joint showed up in the tab used for defining named robot poses.

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And the expected error about the mismatch between the IKFAST joints and the robot joints follows when I try to launch the robot.

[FATAL] [1647248488.944019528]: Joint numbers of RobotModel (7) and IKFast solver (6) do not match [ERROR] [1647248488.944041365]: Kinematics solver of type 'xarm7_pen_ee_xarm7_pen_ee/IKFastKinematicsPlugin' could not be initialized for group 'xarm7_pen_ee'

Questions:

  1. Can I ignore a specific joint (at the middle of the urdf chain) in Moveit's setup assistant?

  2. From your experience, is it possible to control a 7DOF arm as a 6DOF using Moveit and IKFAST solver?

Thank you!

Asked by Robotawi on 2022-03-14 04:15:03 UTC

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