Cooperative Control Of ECAS Based On Multi-agent Theory

Air suspension have the characteristics of low vibration frequency,variable stiffness and adjustable body height,which can improve the ride comfort and stability of the vehicle to some extent,therefore it has been widely concerned and applied at home and abroad.Compared with the traditional air suspension,the electronically controlled air suspension(ECAS)can not only adjust the vehicle body height sensitively,but also cooperate with the adjustable damper to control,alleviate the contradiction between ride comfort and stability,so as to effectively improve the comprehensive performance of the vehicle.Based on the theory of multi-agent,this paper constructs a multi-agent cooperative control system of air suspension from the perspective of body height and damping.Firstly,aiming at the complex nonlinear dynamic characteristics of air suspension system,the air spring,pipeline and air tank models are established;the vehicle dynamic model of dependent suspension is constructed based on the road excitation model and air spring characteristic test data using Lagrange equation.Based on the CAN bus communication protocol and relying on Arduino open-source electronic flat,the data acquisition system of the test sample vehicle is designed,and the accuracy of the vertical and roll characteristics of the vehicle dynamics model is verified by vehicle test.Then,based on the whole vehicle model,the multi-agent architecture of electronic controlled air suspension is designed.Based on the BDI(belief,desire,intension,BDI)agent model,a body height control agent based on fuzzy control theory is designed.Furthermore,based on the damping control strategy of hybrid canopy,a damping control agent is designed.The simulation results show that the intelligent body height control can adjust the body height,and the intelligent body damping control can make appropriate damping adjustment scheme.However,in the case of non-coordination,they do not perform well in improving the overall performance of the vehicle.Finally,based on the multi-agent theory,aiming at the coupling conflict between body height and damper damping,a body-damping cooperative control agent is designed.In the cooperative control agent,the multi-objective optimization algorithm with elitist strategy is used to solve the Pareto front of ride stability and determine the adjustment scheme of vehicle height and damping.Body height control agent and damping control agent complete the task of coordinating control agent release by adjusting their lower controllers.Simulation results show that the ride comfort of the vehicle is improved by 3.8% ~ 7.9% without changing the stability.Comparing with the traditional air suspension vehicle,multi-agent system can alleviate the contradiction between stability and ride comfort.