Research On The Modeling And Control Strategy For Steering-By-Wire System Of Passenger Car

The steering-by-wire system have emerged and it cancel the mechanical connections between steering wheel and steering wheel,with the road feeling motor output torque simulation road feedback force,and through to perform motor control steering wheel steering and it is one of important development direction of vehicle steering system.The technology can be realized to any set of steering gear ratio,play to the effect of different driving modes design corresponding,to make up for the traditional steering system could not have steering portability and handling stability,but the determination method of the steering gear ratio and the front wheel active steering control strategy and road feeling simulation control strategy should be improve.In this paper,the front wheel active steering control and the road feeling simulation control of the steering-by-wire system are studied.First,after using method of reduction of order to deal with the steering-by-wire system and the whole vehicle model,mathematical degradation model of the steering wheel module and the steering actuator module of the steering-by-wire were built respectively,the steering-by-wire system model was built with Matlab/Simulink and the whole vehicle model was built with the Carsim set up a united simulation model.Second,according to the characteristics of the ideal steering ratio,the paper put forward three kinds of design scheme,through the simulation analysis,the scheme that ideal steering ratio was deduced by yaw rate and lateral acceleration by certain proportion relationship was determined,the ideal steering ratio was determined by this solution can meet the needs of different speed running condition.On the basis of that,the paper studied the feedback scheme of the front wheel active steering control strategy,built the model based on single motion parameters(lateral acceleration,yaw rate,side-slip Angle)as the feedback signal model,analyzed the status of the response of the vehicle,and then put forward the full state feedback control,and designed the PID controller.The simulation results showed that the design of the front wheel active steering control strategy can compensate the front wheel Angle in real-time,narrowing the change range of the motion parameters in different speed and the degree of volatility under emergency steering,the strategy is good to improve the driving safety and handling stability,reduce the driver’s burden on driving.At last,based on the ideal steering ratio,with the torque of the traditional steering system as the target moment,and the feedback model of the steering system was established.The fuzzy adaptive PID controller was designed to improve the anti-interference ability of the road feeling feedback of the steering-by-wire system.The simulation results showed that the design road feeling simulation control strategy on the steering wheel torque is able to track the target torque,and has certain anti-interference ability,reduce the influence of the torque mutations caused by the road surface uneven,and guarantee the tracking ability to target torque,it also improved steering portability.