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CIM motor for arm?

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  • CIM motor for arm?

    Hey guys, do you know if we are allowed to use a CIM motor to control the arm? I know that we are allowed 4 total for the hostbot, but has anyone tried this? I think it would be too heavy and too powerful, my mentor tells me a team used the supplied window motors and apparently they werent strong enough. So could anybody chime in on how your arm is being powered? Anything would be helpful. Thank you.

  • #2
    Re: CIM motor for arm?

    There are not rules that I know of (other than safety of course) constraining how you use the 4 allowed CIM motors.

    You need to figure out how much energy you need and see if the CIM is the right motor to provide it. One key parameter you should be interested in the the torque needed to move your arm.

    It's a straightforward Physics problem to figure out how much force is needed, and how long a moment arm you can design into your mechanism. Work with someone who's taken physics (student or mentor). Once you know what you need, compare that to the motor performance on chiefdelphi or .

    The CIM motors have high speed and fair torque. You don't want your arm moving at 3000 RPM, so as you gear down the CIM you get more usable torque.

    The Denso motors have low speed (84 RPM) because they already have a gearbox and very high torque (9 N-m). They have one other feature, because they use a worm-gear design they lock, with enormous holding torque, when the power goes off. This can be a feature, if you want to hold the arm in a particular position without sensor feedback, or a problem if you can't lift your robot without moving the arm because that's not allowed after a match.