Mecanum Polar Drive Help

Technical Java
1

We are attempting using mecanum_Polar drive for our robot this year. According to the WPILib class for Java, it is declared as:

*robotDriveName*.mecanumDrive_Polar(double magnitude, double direction, double rotatation)

The the explanation form the class says that…

  • “magnitude” is it’s speed
  • “direction” determines strafing
  • “rotation” is the spin.

However, when actually applied to the roboRIO, things go awry. What actually happens is this:

  • “magnitude” is actually spin
  • “rotation” is actually speed
  • “direction” doesn’t transmit anything, or the roboRIO reads “0” and doesn’t send code to Talon motor controllers.

Has anyone else experienced or fixed this? Or have we just done something terribly wrong?

2

Could you post your code?

3

*What does your driver interface look like? i.e., how does the driver control each of the 3 degrees of freedom (forward, strafe,rotate)?

Put the bot up on blocks ,then:

a) issue a pure “forward” command and record the direction each of the 4 wheels is spinning

b) issue a pure “strafe right” command and record the direction each of the 4 wheels is spinning

c) issue a pure “rotate clockwise” command and record the direction each of the 4 wheels is spinning

Post your results here.
*
*

4

We had a similar problem the other day and the solution was that two of our motors needed to be inverted.

5

The procedure I described in post#3 allows you to determine which motors need to be inverted, and whether the PWM cables are going to the wrong ports/motors.

6