The set up to drive the motor uses a motor controller cirucit from Pololu that amplifies the pwm signal from a beaglebone.  Although the circuit could use battery power, we are using a high power TI voltage regulator to try to keep the drive voltage stable.  Since motor speed is directly proportional to drive voltage, this should give our motors a little more stable performance.

The schematic of the voltage regulator and motor control circuit [PDF]

Parts and Links

Pololu motor control circuit, 1213

TI voltage regulator, PTN78020WAH [datasheet]

Housing for TI voltage regulator [CAD]

AND gate and SOIC adapter