Model Predictive Thrust Force Control for Linear Motor Actuator used in Active Suspension

Abstract

As the core mechanism of active suspension, the control strategy of linear motor actuator is the key factor to affect ride comfort. This paper presents a model predictive thrust force control (MPTFC) method with switching frequency term in the evaluation function for linear motor applied in the vehicle active suspension system. MPTFC selects seven voltage vectors that the inverter produces into the motor predictive model. The motor operating status parameters of the control cycle are obtained with the effect of different voltage vectors. Based on the evaluation function to select the optimal voltage vector, the optimal vector is used for motor in the next control period. The sky-hook controller of active suspension system and the model predictive thrust controller of linear motor are consisted of the control system of the active suspension. A two-degree-of-freedom quarter-car model with active suspension system was established. The MPTFC and the direct thrust force control (DTFC) for linear motor are experimentally tested by dSPACE. The whole active suspension performance is simulated. Results prove that the suspension using linear motor with MPTFC has faster dynamic response of speed, less thrust force and stator flux linkage ripple, which produces the desired electromagnetic force according to the vibration of the bodywork.