Hey this is my first year with labview and we are using 4 motors crontrolled by sparks with a mecanum drive. One of our motors is spinning slower than the others which is causing our robot to not be able to strafe. I’m wondering if there is a fix I could do through programming and if not what the easiest fix would be.
I guess you could try scaling down the input to the other 3 motors, however it might be a better idea to understand why is one of the wheels slower than the others (maybe mechanically or because of the motor itself).
Another option that you can explore is correcting the angle using an IMU. It is worth considering that it takes an extremely flat surface to have all four wheels in contact with the carpet at any given time, so small changes in the angle are expected unless you have a correction using a similar device.
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Yes, do this first! With the robot and blocks and powered off, try rotating each wheel by hand. The resistance should be the same. If so, figure out where that one is binding (e.g. a gearbox improperly assembled, misalignment).
If not, then run the motors on blocks and see if that wheel is running slower with no load. If so, check that the gearboxes have the same ratio, and that the motor is running at proper speed when disconnected from the gearbox (may be a bad motor).
Edit: Re-reading your original post, is this a problem only when strafing? That is, you can drive forward OK, but not strafe? If so, check that all of the rollers are spinning freely. In going forward, the rollers don’t need to spin, and in rotating, the don’t need to rotate very much. In strafing, sticky rollers is a real impediment. Checking the rollers is not a bad idea anyway.
Poor weight distribution (i.e. more weight at that corner) has caused this issue for us in the past. That might be the cause, but the suggestions above from @GeeTwo and @oscarfonloz are also things you need to check.
Yeah it does move forward fine but our back right wheels seems to be slowing when turning and strafeing.
Overtightened or otherwise sticky/binding rollers on the back right can definitely cause this.
Ok thanks
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