Mecanum Single Joystick Control not working

[Ether]

Originally Posted by pastelpony

Correct me if I'm wrong, but I've been reading that the default mecanum code in the WPI library actually takes the incorrect inputs by default.

Would you please post a link to where you've been reading that?

I don't have access to LabVIEW to inspect its code, but here's the inverse kinematics code taken straight from 2015 WPILib RobotDrive.Java:

wheelSpeeds[MotorType.kFrontLeft_val] = xIn + yIn + rotation;
   
wheelSpeeds[MotorType.kFrontRight_val] = -xIn + yIn - rotation;
      
wheelSpeeds[MotorType.kRearLeft_val] = -xIn + yIn + rotation;
      
wheelSpeeds[MotorType.kRearRight_val] = xIn + yIn - rotation;

I'm not a Java guru, but it looks correct to me.

[pastelpony]

Originally Posted by Ether

Would you please post a link to where you've been reading that?

I don't have access to LabVIEW to inspect its code, but here's the inverse kinematics code taken straight from 2015 WPILib RobotDrive.Java:

wheelSpeeds[MotorType.kFrontLeft_val] = xIn + yIn + rotation;
   
wheelSpeeds[MotorType.kFrontRight_val] = -xIn + yIn - rotation;
      
wheelSpeeds[MotorType.kRearLeft_val] = -xIn + yIn + rotation;
      
wheelSpeeds[MotorType.kRearRight_val] = xIn + yIn - rotation;

I'm not a Java guru, but it looks correct to me.

I'm not quite sure how credible this is, but it sure did help me.

[Greg McKaskle]

I compared the LV code to the attached Java, and they are the same.

The LV code first does a gyro transformation in case you have one and want to use field coordinates.

The code then uses the same expressions on the same inputs with the same output names. The code then normalizes the motor outputs.

If you have an issue with the code, can you be more specific about what was wrong with it?

Greg McKaskle