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Can i use MOveIt package in ROS without closed loop motor control?

asked 2018-08-05 13:10:23 -0500

Robo_Panda gravatar image

I have two DC Servo motors with step and direction pins. But i dont have any feedback from the motor. I had read earlier that moveIt requires closed loop feedback control for operation. Specifications of motor

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I had read earlier that moveIt requires closed loop feedback control for operation

could you please provide a link to where you read this?

gvdhoorn gravatar image gvdhoorn  ( 2018-08-05 14:06:09 -0500 )edit

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answered 2018-08-05 15:16:41 -0500

It is correct that MoveIt! expects to retrieve joint state information, otherwise it would not be possible to know the state the robot is in. This information normally is provided by encoders built into arm joints and then published to ROS on the /joint_states topic. If you don't have encoders on your motors you can always fake sensing joint positions by publishing the commanded joint positions to /joint_states, faking that they have been measured. Depending on your setup this can either work reasonably well (i.e. arm moves slow, your motor are tracking commanded values very well), or utterly fail (i.e. fast motions, significant differences between commanded and actually executed motions).

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answered 2018-08-05 13:17:18 -0500

Prof. xavier gravatar image

Yes, if you are looking to just feed the motors the joint-angles then just make your hardware subscribe the joint_state_publisher topic, angles are published in radians in a form of matrix.

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Asked: 2018-08-05 13:10:23 -0500

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Last updated: Aug 05 '18