2015 Mecanum Drive/Joystick Example

[NeilR]

Mechanum Sample for 2015 seems to be faulty.

We have noticed (and fixed) a few problems in the sample Holonomic Mechanum Cartesian code:

1. The joystick inputs have Rotation, X and Y messed up. We had to fine-tooth-comb which should be hooked to what, but once we found the right VI, it was not difficult.

2. The motor comments that specify which motor gets which port has an error which prevents lateral X motion. We switched the wires between port/motor 1 and 3 and now it works fine.

Not sure how this slipped through, I hope this helps other teams (particularly newbies) to get their mechanums working.

Neil

[pastelpony]

Originally Posted by NeilR

Mechanum Sample for 2015 seems to be faulty.

We have noticed (and fixed) a few problems in the sample Holonomic Mechanum Cartesian code:

1. The joystick inputs have Rotation, X and Y messed up. We had to fine-tooth-comb which should be hooked to what, but once we found the right VI, it was not difficult.

2. The motor comments that specify which motor gets which port has an error which prevents lateral X motion. We switched the wires between port/motor 1 and 3 and now it works fine.

Not sure how this slipped through, I hope this helps other teams (particularly newbies) to get their mechanums working.


Neil

Would you please mind sharing an example of your mecanum code? I'm having difficulty fine tuning it myself.

[NeilR]

In "WPI_RobotDriveMecanumDrive_Cartesian.vi" (accessed by double clicking on the "Drive -- Holonomic Drive" block in the Teleop vi) over on the far left toward the bottom you see "Rotation", "X", "Y" inputs. By rewiring which goes to which input, you can control which joystick motion/wheel controls what behavior.

Please see this image, this is what works for us:

http://pho.to/8fJab

We use the z-axis input for side-to-side motion. On our old joystick that's a little wheel just below the handle.

Neil

P.S. Also, don't forget to swap the wires for motors 1 and 3.

[pastelpony]

We found that Z axis controls strafing too, though moving forward was a great issue.

[ChocolateTiger]

After methodically testing the motors on our breadboard with the original, unchanged holonomic drive roboRIO project, we discovered that the only issue with the program is that the Y and Z (Rotation) axes coming from the array going into the Holonomic Drive VI are switched. It was a minor wiring issue and once corrected, everything worked fine. I have attached a copy of the table showing the correct mapping including the rotational directions of our motors and the true axis to which each belongs.

On the attachment, CW=clockwise, CCW=counter-clockwise

Hope this helps.

[icq10]

Originally Posted by ChocolateTiger

After methodically testing the motors on our breadboard with the original, unchanged holonomic drive roboRIO project, we discovered that the only issue with the program is that the Y and Z (Rotation) axes coming from the array going into the Holonomic Drive VI are switched. It was a minor wiring issue and once corrected, everything worked fine. I have attached a copy of the table showing the correct mapping including the rotational directions of our motors and the true axis to which each belongs.

On the attachment, CW=clockwise, CCW=counter-clockwise

Hope this helps.

Thank you so much for the suggestion! I got almost crazy here and then I started making a chart with the movements and how it is supposed to be. Turned out that the Motors 1 and 2 at the begin.vi had to be switched. I am so happy!