Study On The Integrated Control Of Vehicle Chassis Systems

With the development of automobile industry and engineering technology, the control technology of automotive chassis is more and more applied. Integrated control is a hot issue of research area of vehicle chassis control. Integrated control of systems with power coupling can coordinate the conflict; improve the overall performance of vehicles. Layered integrated control has the advantages of low complexity, high reliability and good scalability. It is the best structure of integrated control.Based on Newton's laws of mechanics, the models of vehicle, body, tires and vertical load are established, By the means of magic formula tire mechanics model, the models of steering and braking systems are established, To Analysis the targets of steering, braking and semi-suspension systems, Controllers of these systems are designed. To Analysis the power coupling of these systems, the integrated controller is designed. Integrated controller can suppress pitching motion to ensure braking performance when vehicle is braking, Integrated controller can suppress Rolling motion and optimize the steering input to ensure that the vehicle handling and 'Stability when vehicle is steering. Integrated controller can calculate the current vehicle movement state to optimize the goal slip of ABS controller. Compare steering and braking response variance to Coordinate the two systems, suppress pitching motion to ensure braking performance.The simulation model of vehicle is built by Matlab/Simulink simulation software. Simulation was conducted to verify the integrated control effect under different conditions. Simulation results show that by the means of integrated control, body pitch angle was well suppressed, the front wheel slip ratio is more stable, braking distance is shorter, and braking performance is improved under braking condition. Yaw rate response time is slightly slower, steady-state yaw rate is smaller, and the volatility of body acceleration has been improved. Dynamic travel of front suspension become smaller, roll angle has been reduced, vehicle handling and stability has been improved under steering condition. The response of yaw rate becomes faster, the maximum increases significantly and the steering performance has been improved. Braking deceleration decreases a little compared to individual control, but by the control of the Attitude of body and Optimization of goal slip, so the braking distance has just been reduced a little. To analysis of simulation results, by the means of integrated control, conflict between systems can be reduced; vehicle handling and stability can be enhanced.