Dual-Redundancy Steering Gear System

Dual-redundancy steering gear system is the steering actuator of vehicle steer by wire system,which can not only implement the basic function of by wire system but also realize the safety demand that the system will not fail because of single fault,so the system has ‘fail/safe/work/alarm' working mode with high safety and reliability.As steer by wire actuator,it can also be used as steering system of autonomous vehicle.Steer by wire system has many advantages such as variable steering transmission ratio,saving the arrangement space of steering system and improving the vehicle handing stability and so on.This research first came up with the redundant configuration of mechatronics redundant steering gear and steering gear redundancy manager which are making up dualredundancy steering gear system according to the high safety and reliability demand,then did Hardware in the loop experiment and simulation experiment based on the combination of Simulink and CarSim,which provide basis research for the research of whole redundant steer by wire system.Mechatronics redundant steering gear system is the steering actuator of high safety and reliability steering gear system.It uses two same steering motors and cylindrical gears parallel coupling then getting through worm gear and worm deceleration institution to drive pinion and rack mechanism steering.The two same angle sensors in the same axle with steering pinion measure the pinion angle synchronously,to proceed the feedback control of steering angle.Redundancy manager has both the steering motor controlling function and redundancy management function.On the one hand,it controls the two steering motors in mechatronics redundant steering gear steering by tracking the target angle of steering wheel input,on the other hand,it does real-time monitoring and diagnosis for the information of angle and current when system operating.When a fault is diagnosed,the system immediately restructures,namely,isolates fault channel,switches to the single redundancy working mode,and send out alarm information.So the system can still operate in the event of a single fault.On the basis of the redundant configuration of mechatronics redundant steering gear and steering gear redundancy manager,this research does system modeling and simulation for dual-redundancy steering gear system,and uses matlab Simulink and CarSim vehicle model to set up the model of dual-redundancy steering gear system to do the simulation of the system steering function and redundancy management ability,so as to verify the steering algorithm and redundancy management logic.On the basis of the simulation model,the system prototype of dual-redundancy steering gear system is installed on the steering test bench to do hardware in the loop test.Through normal dual redundancy steering test and simulated fault test to verify the steering function of redundant steering gear system and the ability of fault diagnosis,fault isolation,system switching and alarming in various types of faults,so as to show the high safety and reliability of dual-redundancy steering gear system.