There are more details in
this thread, but the bottom line is that you need to monitor your battery usage and actually brown out your motors (reduce the voltage you give them) rather than black them out as the RoboRIO will. The RoboRIO can monitor battery voltage and current draw on each circuit (that is, each large motor) through the CAN from the PDP. Probably the simplest thing that will reduce the problem is not to run all of your big motors hard (with high torque) at the same time. For shooting and lifting mechanisms, it may become more common to stretch a spring (or other energy storing mechanism) over a longer period of time to achieve a faster lift or throw than it has been in the past, especially if a team desires to shoot game pieces while engaged in heavy traffic.