Models for Self-Balancing of Two Wheeled Vehicles: A Review

Abstract

In this paper, we have studied the various models, techniques and principles of Self-balancing of two wheeled vehicles. Balancing a two-wheeledvehicle has always been a challenging task.The motion dynamics of a bicycle is very different from other vehicles. Unlike four wheeled or three wheeled vehicles, a bicycle lacks lateral stability when stationary, although bicycles are stable when in motion. Experiments and calculations conclude that a bicycle stays upright when it is steered to maintain its center of mass over its wheels. Either the rider steers to balance the bicycle or the bicycle itself balances above a definite velocity. Factors such as gyroscopic effect, centre of mass, mass distribution contribute in self-stability of bicycle. Numerous projects have been proposed keeping in mind the stability of two wheeled vehicles. Some projects use the concept of flywheels[1] while some use two heavy rotating disks for stability [2]. Most of the projects are based on the concept of inverted pendulum [3][4] and use PID controllers [5] to achieve self-stability. Gyroscopic sensors [4][6][7] are used in some projects which detect the angular tilt followed by a motor to achieve balance.