Syncronous motor speed with encoders

[ekapalka]

Hello! We're considering using building another robot with Mecanum wheels for an off-season project to apply what we know as far as programming, but there may be a problem.... From what I've read, there can be a lot of problems when using holonomic steering if the motors aren't spinning at exactly the correct speed. I'm fairly certain that the absolute value of the wheel speed always has to be the same. I know that the simplest code for holonomic drive is

public void mecanumDrive_Cartesian(double x, double y, double rotation, double gyroAngle)

but, as far as I know, that code wouldn't allow us to control the motor speed independently. Do I have to modify the mecanumDrive_Cartesian.cpp file? I assume that I'll need PID loops somewhere in the program (which I have no idea how to write) to interpret the data from the encoders. Thanks!