Chief Delphi - Jittery Motor

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5580SQUAD

02-02-2015 10:54

Jittery Motor

We hooked up a BAG motor using a versaplanetary gearbox at a 7:1 ratio. It is well greased but it doesn't run smoothly on full forward, and runs terribly on full reverse. We have calibrated them. There is a video below. Anyone have any thoughts?

https://www.facebook.com/video.php?v=987754734586315

Deke	02-02-2015 11:07

Re: Jittery Motor

One thing we had to do this year is grind off the back of one of the pinion pins that is pressed in, to give it clearance. The pin was interfering with other components, and didn't sound healthy when running. That was a 5:1 gear set, but I would suspect that the same tooling is used to assemble 7:1 gear sets as well.

I would check all the components for other interference locations as well, there are a lot of moving parts that might cause headaches.

Other than the minor pin interference, we are very happy with the performance and flexibility of the gearboxes.

Andrew Lawrence

02-02-2015 11:11

Re: Jittery Motor

It is likely the planetary. Have you removed the motor and tested it by itself to see how the motor runs outside the gearbox? If you can isolate the problem to the gearbox itself, it becomes a lot simpler to solve.

DarkRune

05-02-2015 21:16

Re: Jittery Motor

What's the code you are running on it? Something I've noticed with code is that it often oscillates between forward and backwards. You can also try hooking it straight up to a battery and see what happens. You can also check out the talon and maybe switch that out.

nighterfighter

06-02-2015 00:17

Re: Jittery Motor

Quote:

Originally Posted by DarkRune (Post 1439027)

What's the code you are running on it? Something I've noticed with code is that it often oscillates between forward and backwards.

What kind of code are you using that's doing that?

The code really shouldn't cause a motor to oscillate between forward and backwards too often, unless it is a PID loop trying to get to the exact position... (Or if your driver is rocking the robot back and forth.)

topgun

06-02-2015 14:01

Re: Jittery Motor

Check the dowel pins used to hold the planet gears. Each of our 7:1s had a dowel pin that stuck just slightly out of the backside.

BlueOps4216MrG

15-02-2015 07:32

Re: Jittery Motor

Did you guys figure out the problem. We have an almost identical issue. Bag motor w/ 90:1 versaplanetary running with the new Victor SP. It worked fine directly hooked to battery but when running through the motor controller it looks and sounds like yours.

Alan Anderson

15-02-2015 12:12

Re: Jittery Motor

I'm smelling a possible software issue. What is the code you're using to control this motor?

Alan Anderson

17-02-2015 00:26

Re: Jittery Motor

Quote:

Originally Posted by mikel392 (Post 1445461)

not trying to hijack the thread but i'm having the same problem (sort of) https://www.dropbox.com/s/t9coaq7q2d...obot.java?dl=0 the lift goes up fine but it jitters a lot when reversed

Code:

    if (joyExtra.getRawButton(4))

    {

        liftup();  

      }

   

    else

    {

         

        liftstop();

  }

     

     if (joyExtra.getRawButton(2))

     {

        liftdown();  

      }

     

    else{

         

        liftstop();

  }

If button 4 is pressed, it starts the lift running up, but then the fact that button 2 is not pressed stops it immediately. You need to change the logic so that button 4 runs the lift up, button 2 runs the lift down, and only if neither button is pressed does the lift get stopped.

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