Stiffness-damping matching method of an ECAS system based on LQG control  

作　　者：陈一锴 何杰 M.KING 陈无畏 张卫华 

机构地区：[1]School of Transportation Engineering,Hefei University of Technology [2]Traffic Management Research Institute of the Ministry of Public Security [3]School of Transportation,Southeast University [4]Centre for Accident Research and Road Safety-Queensland,Queensland University of Technology,Kelvin Grove 4059,Australia [5]School of Mechanical and Automotive Engineering,Hefei University of Technology

出　　处：《Journal of Central South University》2014年第1期439-446,共8页中南大学学报（英文版）

基　　金：Projects(51305117,51178158)supported by the National Natural Science Foundation of China;Project(20130111120031)supported by the Specialized Research Fund for the Doctoral Program of Higher Education;Project(2013M530230)supported by the China Postdoctoral Science Foundation;Projects(2012HGQC0015,2011HGBZ0945)supported by the Fundamental Research Funds for the Central Universities,China

摘　　要：A novel method of matching stiffness and continuous variable damping of an ECAS(electronically controlled air suspension) based on LQG(linear quadratic Gaussian) control was proposed to simultaneously improve the road-friendliness and ride comfort of a two-axle school bus.Taking account of the suspension nonlinearities and target-height-dependent variation in suspension characteristics,a stiffness model of the ECAS mounted on the drive axle of the bus was developed based on thermodynamics and the key parameters were obtained through field tests.By determining the proper range of the target height for the ECAS of the fully-loaded bus based on the design requirements of vehicle body bounce frequency,the control algorithm of the target suspension height(i.e.,stiffness) was derived according to driving speed and road roughness.Taking account of the nonlinearities of a continuous variable semi-active damper,the damping force was obtained through the subtraction of the air spring force from the optimum integrated suspension force,which was calculated based on LQG control.Finally,a GA(genetic algorithm)-based matching method between stepped variable damping and stiffness was employed as a benchmark to evaluate the effectiveness of the LQG-based matching method.Simulation results indicate that compared with the GA-based matching method,both dynamic tire force and vehicle body vertical acceleration responses are markedly reduced around the vehicle body bounce frequency employing the LQG-based matching method,with peak values of the dynamic tire force PSD(power spectral density) decreased by 73.6%,60.8% and 71.9% in the three cases,and corresponding reduction are 71.3%,59.4% and 68.2% for the vehicle body vertical acceleration.A strong robustness to variation of driving speed and road roughness is also observed for the LQG-based matching method.A novel method of matching stiffness and continuous variable damping of an ECAS （electronically controlled air suspension） based on LQG （linear quadratic Gaussian） control was proposed to simultaneously improve the road-friendliness and ride comfort of a two-axle school bus. Taking account of the suspension nonlinearities and target-height-dependent variation in suspension characteristics, a stiffness model of the ECAS mounted on the drive axle of the bus was developed based on thermodynamics and the key parameters were obtained through field tests. By determining the proper range of the target height for the ECAS of the fully-loaded bus based on the design requirements of vehicle body bounce frequency, the control algorithm of the target suspension height （i.e., stiffness） was derived according to driving speed and road roughness. Taking account of the nonlinearities of a continuous variable semi-active damper, the damping force was obtained through the subtraction of the air spring force from the optimum integrated suspension force, which was calculated based on LQG control. Finally, a GA （genetic algorithm）-based matching method between stepped variable damping and stiffness was employed as a benchmark to evaluate the effectiveness of the LQG-based matching method. Simulation results indicate that compared with the GA-based matching method, both dynamic tire force and vehicle body vertical acceleration responses are markedly reduced around the vehicle body bounce frequency employing the LQG-based matching method, with peak values of the dynamic tire force PSD （power spectral density） decreased by 73.6%, 60.8% and 71.9% in the three cases, and corresponding reduction are 71.3%, 59.4% and 68.2% for the vehicle body vertical acceleration. A strong robustness to variation of driving speed and road roughness is also observed for the LQG-based matching method.

关 键 词：matching method electronically controlled air suspension linear quadratic Gaussian genetic algorithm 

分 类 号：U461[机械工程—车辆工程]