Self-Balancing Control of a Four Wheeled Vehicle

For cars or trucks on the verge of roll-over, the boundary between stability and instability occurs when the vehicle balances on two wheels on the same side. In this work, the open-loop steering servo of an off-road type vehicle is used in a closed-loop balance control system that actuates the front steering angle so that the vehicle self-balances and drives on two wheels. A nonlinear vehicle model was linearized about the equilibrium balance point, and classical control techniques were used to obtain a stabilizing control system. A relatively simple contact force model was created in order to model the vehicle’s tire interaction with the ground. It is demonstrated analytically and experimentally that the control law developed for this system is able to retain the equilibrium balance angle of the vehicle even while it encounters significant disturbances. An 8 bit Atmel AVR Butterfly microcontroller was used to implement the control law on-board the vehicle.