Need Mercanum Help

[BlackKnight219]

We are trying to program a mercanum drive prototype and only have two Talons and two Jaguars. How can we program it to run using these motor controllers? Help is much appreciated.
Thanks,
Team 4809

[solomondg]

Here's a document that might help you out:
https://www.chiefdelphi.com/media/papers/download/2934

[Ari423]

Is mercanum a new drive system, or yet another misspelling of mecanum? If it is a misspelling, check out Ether's mecanum analysis here. If it's a new drive system, I've never heard of it so good luck.

[BlackKnight219]

Okay, thanks. Hopefully this helps.

[adciv]

If you're using labview, it's already programmed in. See the 'Holonomic Drive' vi

[Jonathan L.]

The TeleOp programming should be straightforward as described above. To your question about the different motor controllers.

There is not a ton of difference between the PWM signals used for different motor controllers. However, I would recommend re-calibrating all the motor controllers (really with any motor but) especially with option 1 below. Also, there may be a difference with linearity and I'm not sure how much software helps.

1. In the Begin VI use the Open 4 motors VI. On the drop-down menu below the VI select either Talons or Jaguars. Re-calibrate ALL motor controllers with THE SAME motor controller selected.

2. Use the same Open 4 motors VI but select Existing Motors from the drop-down. You can then wire in individual motor references, selecting the appropriate motor controllers for each motor.

[GeeTwo]

Originally Posted by Jonathan L.

There is not a ton of difference between the PWM signals used for different motor controllers.

Except Jaguars. Talons and Victors and SPARKs and SD540s are practically interchangeable unless you're working at the edge of the envelope, but Jaguars use a different span of pulse widths than the others; be sure that you use the jaguar objects to control jaguars and talon objects to control talons. Calibration of the motor controllers is particularly important if you do NOT have an encoder on each wheel; if you are using encoders*, this should automatically compensate for any minor mis-calibration.

* I have read posts of teams who depend strongly on feed-forward and provide high values for P and D in their PID loops but leave I at zero, even for velocity control. I am not sure through any experience if this statement is true if you use the encoders this way, but my back-of-the-envelope figuring seems to indicate that this would still compensate for minor mis-calibration.