Omnidirectional robot simulation

I have a kiwi drive robot I'd like to simulate in gazebo. As I haven't found a way to simulate omni wheels I've tried modelling the base off of the pr2, which achieves omnidirectional movement by mounting all of its wheels on casters. The rotation of the casters on the pr2 is controlled with a pid controller, which means to go from translating in x to translating in y there is a delay while the casters change the wheel direction. I'd like to avoid this delay in the simulation since the kiwi drive will not experience this delay. So my questions:

1) Is there a more direct way of simulating omni wheels or an omnidirectional robot that does not need to wait for the wheels to turn?

2) Is there a way to have the casters move immediately to the desired angle rather than wait while they are turned by a pid controller?

Thanks

Asked by avidbot1 on 2015-03-04 10:58:03 UTC

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Answers

You could create a model of the omni-wheel. It looks like a cylinder with a few passive cylinders would work. This would require a bit of work, especially when tuning the various model parameters.

You could also fake the desired behavior by creating a low-friction base, and then apply forces directly to the robot. The effect would be more like a hover craft however.

You could create a wheel that consists of two cylinders that overlap, but with a 90 degree rotation offset. One of the cylinders would be controlled, and one passive.

Asked by nkoenig on 2015-03-04 11:37:50 UTC

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You could check out this link. It is a Gazebo simulation for omnidirectional soccer-playing robots. Basically, as Nate said, I faked the desired behavior by applying velocities directly to the robot. However, I still would like to try to create a realistic omnidirectional wheels in the future.

Asked by winston on 2017-04-19 21:06:58 UTC

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Check out GuiRitter's https://github.com/GuiRitter/OpenBase repo.

His omni-wheel xacro model works pretty well. I just successfully ran the demo in Gazebo.

Asked by josephcoombe on 2019-02-07 18:25:40 UTC