jaguar speed control of mecanum wheels

[Ether]

Two series of questions:

1) all the Jaguar literature I have been able to find speaks of the PWM input signal as being a "speed" signal. Is this really true, or is the term being used loosely? Is the jaguar somehow sensing the back-emf on the motor power leads and using this to sense motor speed, and using this in a closed-loop circuit to control motor speed? Or does the PWM signal simply map into a voltage command to the motor (in which case the speed would vary with load)?

2) with a robot that is using mecanum wheels, how critical is it that the individual wheel speeds be accurately controlled? is it sufficient to just send the PWM signal to the jaguars as mentioned above? or do we need to install an encoder on each wheel? if an encoder is necessary, can we run that encoder signal directly back to the jaguar? in other words, does the jaguar have built-in motor speed control if the encoder is wired to it? Or do we have to wire the encoders back to the cRIO and write our own speed controller in software?

I know some of these questions could be answered by some simple tests, but I don't have access to the hardware right now and am trying to gather as much info as possible before our next team meeting.

Thanks.


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