Strange Jaguar/CIM Motor Behavior

[Jimbo2032]

My team is having some trouble getting our robot to drive in a predictable fashion. We are a first year FIRST team, so please bear with me. We implemented Mecanum wheels with 4 CIM motors being driven by Jaguars (PWM). Our code is written in LABView.

Going forward and backward works as it should, however, when we attempt to translate left or right the robot wants to rotate about it center axis. Upon inspection of the code the joystick inputs X and Y were wired to the appropriate terminals on the holomorphic .vi (cartesian).

The symptoms that I see are that the motors are not all engaging at the same time or the same speed. I feel that we need some type of feedback control loop but I wanted to ask here before we expend that time and effort. Could it be that I am missing something? And if so, any suggestions no matter how simple or mundane will be appreciated.

Thanks in advance for your help!

Jimbo