Finite frequency multi-objective control of vehicle active suspension with road preview information

A finite frequency linear parameter-varying (LPV) controller design approach with look-ahead preview measurements was presented, and the proposed approach was applied to a multi-objective control problem of vehicle active suspension systems with time-varying velocity. Firstly, the Padé approximant method was used to deal with the preview information, so as to get the augmented system of active suspension with velocity information in the form of state-space equation. Secondly, the time-varying velocity was described by a polytope with finite vertices. As human body is fairly sensitive to the car body vertical acceleration within 4~8 Hz, and road disturbance happens only within the finite frequency domain range, the traditional H∞ method over the infinite frequency range can not result in the optimum control plan obviously. The H∞ norm of the car body acceleration was used as the performance optimization index to make it acquire the optimum energy gain attenuation within the concerned frequency band. In addition, the time-domain constraint conditions were guaranteed as well. The controller, whose gain matrix depended on the measurement information of the velocity, was designed in the form of linear matrix inequality (LMI). Finally, a numerical example was used to verify the reliability of the method, simulation results illustrated the usefulness and advantages of the proposed method and the designed controller can achieve better comfort than the traditional entire frequency-domain control approach and ensure that hard constraints are satisfied. © 2015, Chinese Society of Agricultural Machinery. All right reserved.