The AX-12W servo actuator from Robotis is a wheeled variant of the popular AX-12A. Essentially this servo is an AX-12A with a lower gear ratio so that a much higher RPM can be achieved, making it ideal for use in 'Wheel Mode' as opposed to the traditional 'Joint Mode'. The AX-12W robot servo has the ability to track its temperature, voltage, and load. As if this weren't enough, the control algorithm used to maintain shaft position on the ax-12 actuator can be adjusted individually for each servo, allowing you to control the speed and strength of the motor's response. All of the sensor management and position control is handled by the servo's built-in microcontroller. This distributed approach leaves your main controller free to perform other functions.