Hardware-In-The-Loop(HIL) Simulation And Road-Test Of Anti-Slip Regulation (ASR) For 4*2 Heavy-Duty Vehicle

With the development of automobile industry,more and more demands to vehicle safety capability are taken into account. When vehicle starts or accelerates on the soft road or the road with low coefficient of friction, the wheels will slip excessively because of the low adhesion that the road surface provides. It causes the longitudinal and lateral adhesions to further reduce. And the vehicle stability,handling and acceleration will greatly reduce. Anti-Slip Regulation(ASR) is coming to be a popular feature on many vehicles because it can prevent the driven wheels from slip during vehicle accelerates especially when vehicle starts,accelerates or corners and improve vehicle's acceleration stability and handling.It is based on the principle that maintaining the driving slip ratio value round the optium slip ratio so that traction can not only be fully used but also the lateral stable potentiality is guaranteed.Generally,ASR includes two components, namely, active brake control and engine torque control. According to this theory, with the focus on the active brake control and engine torque control, this paper has constructed the HIL simulator and simulated control algorithms in road-test, and proved its efficiency and ability to control ASR system. This article mainly included four parts: (1)Vehicle's dynamic models The vehicle dynamic models comprise several key parts of vehicle, such as engine,transmission,tyre,whole vehicle and etc. Engine model contains two parts, which are static state model and dynamic model. The former is modeled according to the speed characteristic experiment, then polynomial fit these experiment data (output torque and engine speed); the latter is modeled by simplifying the engine dynamic process as once inertia system with a transport delay. In the case of transmission, we regard clutch,gear-box,power transfer,transmission shaft and half shaft as the components whose function are only transferring the torque. Tyre model adopts the GIM theory model. And the whole model employs the seven freedom model ,which includes longitudinal displacement,lateral displacement,sway angle displacement and four wheels rotation movement that encircle their own axis. These models are used to reflect the subsystem's influence on the dynamic of whole vehicle and observe the running statement of vehicle. And the corresponding simulation models are established with SIMULINK, which provide an off-line simulation platform for debugging the control algorithms. (2)modification of vehicle's hardware As there is no ASR hardware fixed in the vehicle and it is impossible to have ASR control for the vehicle.To meet the needs of experimentation,it is necessary to give some modifacition to the brake and acceleration hardware,so that we can control them and add ASR control to the vehicle,it is also a preparation for HIL and road-test. (3) Hardware-in-the-loop simulator Since the late 1980's various testing methods based on the microprocessor have been developed as a result of efforts to ensure the capability of automotive control systems. HIL originated in the aerospace and defense industries where it is frequently impossible,impractical,or just too costly to test controllers on actual systems.An economic and efficient test method...