A Cascade PD Controller for Heavy Self-balancing Robot

This paper describes control system for dynamic equilibrium finding of a self balancing (two-wheeled) heavy robot. Two cascade-connected Proportional-Derivative (PD) controllers are used to balance the robot and keep the desired driving speed (or standing still). A simple and efficient algorithm for tilt calculation takes data from three sensors: a gyroscope, an accelerometer and a contactless magnetic encoder. The PD controller output is combined with manual (remote) driving signals to control Electronic Speed Controllers (ESC) of two high-torque electric motors. Finally, experimental results and recommendations to cope with difficulties are discussed.