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Unread 17-01-2015, 18:44
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Mecanum Polar Drive Help

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

Code:
*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?
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Unread 17-01-2015, 18:47
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Re: Mecanum Polar Drive Help

Could you post your code?
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Unread 17-01-2015, 19:22
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Re: Mecanum Polar Drive Help


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.

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Unread 18-01-2015, 00:49
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Re: Mecanum Polar Drive Help

We had a similar problem the other day and the solution was that two of our motors needed to be inverted.
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Unread 18-01-2015, 08:38
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Re: Mecanum Polar Drive Help

Quote:
Originally Posted by SoftwareRachel View Post
We had a similar problem the other day and the solution was that two of our motors needed to be inverted.
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.


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