Characterisation of a motor driver with over-current protection and speed feedback

Urban search and rescue robots are becoming more prolific and widely used. However, these robots are still being developed for specific environments and situations. The research being undertaken at Massey University is part of a larger collaboration to produce a multi-tiered robotic system for urban search and rescue. The first major hurdle of a mobile robotic system is mobility. While this research will ignore the difficulty of hazardous terrain, stable and controllable maneuverability is still required. To achieve this, a motor controller system has been designed and developed. Each controller will control a wheel of the robot and maintain a speed determined by a central computer. The motor controller requires the ability to control the motor speed and check that the current drawn is not too high as to damage the motors or other hardware. This paper outlines the structure of this motor controller system as well as the testing undertaken to determine the PID constant for the control loop. The testing has resulted in a set of PID constants that control the system, within pre-defined metrics, very effectively.