| In order to quickly rescue all kinds of sudden disasters and natural disasters,higher requirements are put forward for improving the mobility of emergency rescue vehicles(ERVs).How to ensure the vehicle stability under high mobility becomes the key technical demand for ERVs.Active front steering(AFS)and hydro-pneumatic suspension(HPS),as important chassis subsystems,can improve the vehicle yaw stability and roll stability,respectively.Hence,it is vital to build a reasonable and effective control strategy to coordinate AFS and HPS systems to improve the stability of ERVs at high speed.This paper is funded by the National Key Research and Development Program“Research and application of key technologies for high-mobility and multifunctional ERVs”(Project Number: 2016YFC0802900).This paper focus on the control strategies of AFS and HPS systems of ERVs,which consists of the multi-objective optimization and control method of HPS,the intervention mechanism and control strategy of AFS,and the decoupling control algorithm of AFS and HPS systems.Furthermore,the experiments on the self-developed fire rescue vehicle are conducted to validate the proposed control strategies.The main contents of this paper are as follows.(1)The multi degree of freedom dynamic model,nonlinear magic tire model and road input model of ERVs are established and verified on the Matlab/Simulink platform,which lays the model foundation for the dynamics simulation of ERVs under different working conditions.(2)A multi-objective optimization and roll stability control methods for HPS system of ERVs are proposed.The road-tire-suspension-body model is established on the AMESim/Simulink co-simulation platform,based on which the sensitivity of HPS system is analyzed,and then the improved multi-objective optimization algorithm is used to optimize the parameters of HPS system.The vehicle roll stability control logic based on HPS system is proposed through building the control model of HPS system,and the variable structure sliding mode controller based on the exponential reaching law is designed.Meanwhile,the parameters of the sliding mode controller are optimized by the parallel adaptive clonal selection algorithm.(3)The intervention mechanism and yaw stability control method for AFS system of ERVs are presented.Combined with double line and yaw rate methods,the closed polygon stable area of ERVs is constructed,and then the intervention mechanism of AFS system is proposed.In order to track the vehicle's ideal yaw rate and sideslip angle,a sliding mode control strategy of HPS system for improving the yaw stability of ERVs is proposed,and the vehicle's sideslip angle is estimated based on extended Kalman filter algorithm.(4)The decoupling control strategy for HPS and AFS systems of ERVs is put forward.The vehicle dynamics model with three degrees of freedom including lateral,yaw and roll motions is constructed,and the reversibility of the vehicle chassis is analyzed by the interaction algorithm.On that basis,the generalized regression neural network(GRNN)is adopted to identify the vehicle chassis inverse system,the vehicle chassis system is decoupled into two independent pseudo linear systems.Furthermore,the decoupling control strategy composed of PID and GRNN inverse system is designed to regulate the vehicle's yaw rate and roll angle,so as to realize the decoupling control of the vehicle chassis system.(5)The mechanical and hydraulical systems of the chassis of XJY18 D rescue vehicle are designed,and then the manufacturing,assembly and test of XJY18 D rescue vehicle are completed.Based on the self-developed rescue vehicle,the proposed HPS control strategy,AFS control method,and decoupling control strategy are tested.The HPS and AFS control strategies of ERVs proposed are helpful to improve the vehicle stability at high speed and promote the rescue efficiency of ERVs greatly,as well as of significance for the application and industrialization promotion of emergency rescue equipment. |
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