Simultaneous dynamic system estimation and optimal control of vehicle active suspension

Abstract

This paper proposes a combined observer/controller method that estimates the states and simultaneously improves the ride comfort and stability of a full vehicle active suspension system using a single inertial measurement unit (IMU) in the presence of noise and centre of gravity uncertainties. The derived model is based on a channel-by-channel estimation technique using filtered white noise excitation signals on all the wheels, as well as active suspension actuators. The transfer functions of the vehicle system are estimated by analysing the IMU signals in the frequency domain. The derived result is then used in a linear quadratic regulator to calculate the actuators' forces to improve the vehicle's ride comfort and road holding stability within the limits of the rattle space. The simulation results show the efficacy of the proposed approach. Specifically, the observer estimates the actual behaviour of the vehicle with 95% accuracy with up to 20% uncertainty. Finally, a parametric study has been investigated to ascertain the applicability of the proposed approach in estimating the vehicle dynamics with simultaneously improving the ride comfort and road holding stability.