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Getting real time torque values from Rviz during move execution

asked 2016-06-26 14:18:52 -0500

t27 gravatar image

I'm using Rviz to analyse the dynamics of a 6 DOF robotic arm model (UR5 from the ros industrial repos).

I want to obtain real-time dynamic torque values for all joints while executing a Planned move(Motion Planning -> Planning).

As of now, I'm able to simulate the motion by selecting the start and end states. I am also able to obtain static torque values for any given state through the onscreen display of torque values(Displays -> MotionPlanning -> Planning Metrics -> Show Joint Torques). But, while executing a move, these torque values don't update dynamically.

I primarily want to know of torques due to the acceleration of the joints when executing a particular move. Is there any way to get these torque values on Rviz, or maybe even through Moveit via code?

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Just a note: RViz is not a (dynamic) simulator. The values you are referring to are calculated by the MoveIt RViz plugin, and are based entirely on the contents of the URDF that is loaded at that time. Rarely do URDFs contain the necessary info to make those values anywhere near accurate.

gvdhoorn gravatar image gvdhoorn  ( 2016-06-26 14:27:02 -0500 )edit

Could you suggest any way to get dynamic values from the URDF/SDF? I'm OK with the accuracy for now.

t27 gravatar image t27  ( 2016-06-26 15:09:28 -0500 )edit

You mention SDF here, which is the format used by Gazebo, which is a dynamics simulator. Perhaps unnecessary, but please understand that RViz != Gazebo. If you meant SRDF, then that is a format used by MoveIt.

gvdhoorn gravatar image gvdhoorn  ( 2016-06-27 04:37:53 -0500 )edit

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answered 2016-06-27 04:36:15 -0500

gvdhoorn gravatar image

I don't know of any way to get these values 'out' of RViz (they're not published on a topic fi).

As I wrote in my earlier comment, these are calculated by the MoveIt RViz plugin. Searching the sources, they appear to be calculated in MotionPlanningDisplay::computeMetricsInternal(..) (here), using an instance of the DynamicsSolver class. Lacking any way of getting the values out of the plugin, you could see whether you can instantiate a DynamicsSolver yourself and have it calculate things for you whenever you want.

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I ended up using Matlab's SimMechanics finally. I only wanted the dynamics values in a few cases and simmechanics took less time than modifying the code. Thanks

t27 gravatar image t27  ( 2016-10-23 06:53:08 -0500 )edit

@t27 how to use SimMechanics for CAD model Dynamics value ?

lagankapoor gravatar image lagankapoor  ( 2018-06-07 00:16:49 -0500 )edit

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Asked: 2016-06-26 14:18:52 -0500

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Last updated: Jun 27 '16