Does anyone have this odd problem??

Our robot’s drivetrain moves but something odd happens. Using the default code to drive it one drill motor starts to turn before the other one when we turn the joystick gently. It works at high speeds I think. Also which gearbox posistion is high gear??What can be the problem?

my old team had this problem last year and what it came down to was this…even as motors are rated the same there is a slight difference in what voltage it takes to make the motors start. the solution to this problem was in software…the software people wrote a program that went and increased voltage by very small increments until the exact voltage that started the motors was found. then they controlled the starting voltage given to each motor within the software…I really can;t give you any more specifics but I can try and find out from my old team exactly how they did it and I’ll post my findings…Hope this helped a little

Two things to think about.

1). In the past, using the Victor 883 controllers, there was a built-in deadband of 10%. The controllers wouldn’t start driving the motors until more than 1.2 V was requested. I believe the 884s don’t have that deadband. Have your software folks put one in the code. EXAMPLE - If output is less than 137, then set it to 127. Something like that.

2). The drill motors run differently in reverse than forward. More than likely, you have one motor running backwards relative to the other. This is expected. Think about it. There will be a slight efficiency difference between your port and starboard motors since they are facing in opposite directions. This has something to do with the brushes being asymmetric.

The 10% deadband should clear up your problem. Good Luck.