How to implement a passive caster wheel

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Hello!

I’m building a diff drive robot with a passive caster-wheel that has to navigate close to obstacles. Switching from forward to backwards movement leads to a well visible wiggle movement of our robot and we would like to integrate this effect into our simulation to see if and how we have to adapt our trajectory. All robots I have seen so far use a simple sphere as caster wheel and don’t simulate the wiggle effect.

Is there a robot-description that already implements such a caster wheel?