I got the following homework question:

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> What are the general differences between robots with Ackermann steering and standard bicycles or tricycles concerning the kinematics?
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But, I don't see what differences there should be, because a car-like robot (with 2 fixed rear wheels and 2 **dependent** adjustable front wheels) can be seen as a tricycle-like robot (with a single adjustable front wheel in the middle).

Then, if you let the distance between the two rear wheels approach zero, you get the bicycle.

So, I can't see any difference between those three mobile robots. Is there something I am missing?