Adaptive backstepping control with nonlinear disturbance observer design for active suspension and mechanical elastic electric wheel system

Abstract

In order to make up for the disadvantages of common wheels, a novel type of mechanical elastic electric wheel (MEEW) structure is designed and applied to electric vehicles in this paper. To improve ride comfort and stabilize the attitude of the motor system, an improved adaptive backstepping control strategy with nonlinear disturbance observer (NDOB) technology is further constructed for electric vehicle equipped with MEEW system. In consideration of uncertain factors and nonlinear characteristics, the quarter vehicle model of active suspension and MEEW system is established. An adaptive control strategy is adopted based on backstepping technique, which can simultaneously estimate uncertain sprung mass and unknown stiffness or damping coefficients. Meanwhile, the designed disturbance observer is able to suppress the influence of external lumped disturbance and compensate estimation errors. Finally, simulation experiments are developed to demonstrate the advantages of proposed control scheme and verify the effectiveness of designed observer in the presence of uncertain disturbance.