Research On The Layered Integrated Control Of The Vehicle's Chassis System

The vehicle's chassis system includes suspension subsystem, steering subsystem and braking subsystem which have the inter-coupling actions. When vehicle is running, the inter-coupling actions affect the ride comfort and braking performance of the vehicles. In order to improve the vehicle's integrated performance, it is necessary to make an integrated control of the above three systems. This is a current and many researchers have interest in it.In this paper, we establish the dynamic models of active suspension system (the agneto-rheological fluid damper is used.), electric power steering system and anti-locked braking system, and design respectively optimal preview controller for the active suspension system, fuzzy PID controller for electric power steering system and logical threshold controller basing on the sliding rate of the wheel for the anti-locked braking system according to the above models. The simulation results show that the three controllers are realizable and effective on their own system, but when the three controllers work at the same time, vehicle can't satisfy the performances on different conditions.A layered integrated control is designed basing on contacts of active suspension system, electric power steering system and anti-locked braking system, namely, three subsystems are controlled respectively and the integrated controller is designed to harmonize three subsystems. In the environment of Matlab/Simulink, integrated system of ASS, EPS and ABS is simulated and the results of simulation are compared and analyzed under integrated control and combined control, from which we can see that adopting the strategy of integrated control can not only enhance the brake performance, but also ameliorate the performance of ASS, making the vehicle's integrated performance to be improved. This has a directive meaning for the after deeper development of integrated control system of the whole chassis.