How Do mecanum wheels handle the bumps?

[JesseK]

Originally Posted by Ether

http://www.chiefdelphi.com/forums/sh...6&postcount=33

Refer to RobotA mentioned in the thought experiment in the post at the link shown above.

If the motor is providing a torque of 40 in-lbf to a wheel, and the wheel is not slipping, then the carpet MUST be reacting with a force of 10 pounds (for a 8" diameter wheel) in the plane of the wheel, acting against the wheel trying to push it forward. The forward component is 10 pounds (the exact same forward component you would get with a standard wheel). It cannot be otherwise.

And yes, with the mecanum wheel there are additional vector forces at play. But they do not subtract from the 10 pounds. I encourage those of you who are using the "vector" argument to think a bit more about how the vectors are created.


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I will concede in that the split second before the rollers start to slip there is an instant the wheels put all force directly forward. Yet this split instant of an isolated experiment doesn't translate to assisting a driver in pushing due to the dynamics of the holistic system. The driver doesn't go up to something, stop, and THEN push the object. The only scenario in which this may minutely apply is in a situation of pinning. Yet even then, the instant the robot moves it turns into a dynamic situation -- the rollers slip, the tractive forces only translate 70% torque, and thus the bot remains pinned.