Study On Adaptive Control System Of Steering Vehicle-to-Vehicle Longitudinal Distance

In this paper, aimed at the control problem of the vehicle-to-vehicle dynamic system, the study of the structural characteristics and the modem control technologies for this system have been conducted. The purpose of this study is to provide theoretical and technological support for realizing the vehicle-to-vehicle longitudinal distance adaptive control. The main research works are presented as follows:(1) A simulation model of the vehicle dynamic system is established. In order to simulate the actual operating condition of the vehicle perfectly, and provide the satisfactory simulation platform for research work, the effect of non-linear elements about the engine, torque converter, automatic gear switch and brake system are taken into consideration in this model. The stateflow program based on the finite state machine (FSM) concept and its application in the switch control of simulation system has been also discussed.(2) The structural characteristics of the vehicle-to-vehicle dynamic system are analyzed. Focus on the form, type of the vehicle-to-vehicle control information and their matching characteristic reciprocally, the effect of these factors on dynamic system modeling is studied, and further improvement of the method of designing the vehicle-to-vehicle control strategy has been done. Then based on the second-order model, a third-order longitudinal dynamic model is derived, which contains more control information, and achieved more higher control precision, and the control effectiveness between these two models is compared under simulation test.(3) Based on optimising the design of vehicle-to-vehicle control strategy, the application of sliding mode variable structure control (SMC) and linear quadratic optimal control (LQ) theory in the vehicle-to-vehicle longitudinal distance adaptive control is studied. The control precision of the system and the dynamic response characteristics with two algorithms are compared respectively.(4) After analysing the dynamic characteristics of sliding mode in the boundary layer, a non-linear saturation function subject to proportion-integral-differential control in order to eliminate the chattering is proposed. Simulation results demonstrated that the method not only reduced the chattering, but also guaranteed the insensitivity of system to external disturbances and parameter uncertainties, and improved the dynamic quality of system.