High-speed motion control of wheeled inverted pendulum robots

A high-speed motion control technique for inverted pendulum robots using unstability is introduced. Inverted pendulum is a self-regulated system that simulates the motion of a child swaying an umbrella or stick. The controller design for various pendulums was widly challenged during the 1980s. Later, the machines for human riding using this principle were developed and sold in the U.S. In addition, many biped walking robots have been developed based on this principle. Basically, inverted pendulums are automatically controlled as they do not fold up. However, this paper presents a contradicting theory. The controller of the inverted pendulum deliberately breaks down the balance while in motion. This shows that the controller is based on the unstability of the pendulum system. And when the pendulum stops, the controller regains the balance. For implementing this concept, the controller is designed using partial feedback linearization, which controls the tilt angle of the pendulum robot. At first, the horizontal position of the robot is neglected by the controller. However, the position of the pendulum successfuly becomes controlled as a result. This paper presents the simulation and experimental results to establish the adequacy of the proposed method.