[SudoSammich]

Well first off, there's not really enough information to fully diagnose your problem, but we're using holonomic drive this year (controlled the same way), so I've got a couple things that might cause a problem like that.

First off, are you using the RobotDrive class (Java) or .vi (LabVIEW) or...whatever the equivalent library in C++ is? That actually does work really well right out of the box for controlling mecanum drive. I was originally going to write our own code for the drive system, but it does save a lot of time to not reinvent the wheel (if it is a little less fun).

Second, make sure your jaguars are plugged in and instantiated correctly. We've had enough times throughout the years where "lfJaguar" actually turned out to be the back right one for this not to come to mind. Also, if you're using the RobotDrive object, make sure the jags are in the correct places.

Lastly, check how you put in your joysticks. Earlier this year we had an interesting problem with the arcade drive mode for our bot before we realized the X axis was plugged into Y and Y was plugged into X.

Not sure if any of these will help, but good luck!