Mecanum code problems

[BenjaminMiller]

I am trying to program a test chassi for mecanum but currently running into the edu.wpi.first.wpilibj.MotorSafety.check(MotorSafety.java:139): error
this is my code

GitHub - FireIslandFRC/mecanum_0

[bovlb]

Not directly related to your reported problem, but one thing I notice is that when you create the Drive command in RobotContainer.RobotContainer(), you are passing in integer axis channel numbers that you are then treating as doubles to be passed to MechanumDrive.driveCartesian.

You probably want to switch to using DoubleSuppliers here. See this example code and also this article.

Also, you’re probably going to decide you want field-oriented control, which means you should be using the four-parameter version of driveCartesian, except I don’t see a gyro in your code.

I’m not sure what’s causing your MotorSafety problem. This problem is caused by not calling feed often enough.

In your code, feed is called by MecanumDrive.driveCartesian(), which you are calling in Drive_sub.drive(), called from Drive.execute(), which is set as the default command.

When I see this issue, it’s usually because there is another command running that isn’t using the same interface, or sometimes because some method in the main event loop is taking too much time. I don’t see that this should be the case in your code.

Can you show us a screenshot of your error message, with as much context as possible?

[bovlb]

Aha! I see the problem. You’re not creating RobotContainer in Robot.robotInit(). Also, you should not have the m_DriveSub be a static member in RobotContainer().

[BenjaminMiller]

Thank you, I will try to implement these things next time I get my hands on the robot.
One question though: how would you make it robot oriented?

[bovlb]

You already have robot-oriented with the three-parameter version of driveCartesian. The common wisdom is that most drivers prefer field-oriented, but if you have no gyro, then there’s not much you can do.

[BenjaminMiller]

Do you just put the gyro on the 4 parameter, and can I use the built in gyro in the robo rio

[bovlb]

Yes (using m_gyro.getRotation2d()), but no because:

Built in Roborio gyro

The RoboRIO has a built-in accelerometer but does not have a built-in gyro. You will have to use an external gyro sensor, either SPI (e.g. ADXRS450) or analog, or something like a NavX or Spartan Board which provides a gyro via the MXP expansion port.