Study On Control Strategy Of Hybrid Electric Bus EPS System

Electric power steering system (EPS) is a new power steering system, which withexcellent power characteristics, reasonable cost, energy saving advantages quicklybecome a hot automotive research. Currently, EPS system on the car has been veryextensive, but applied on the large commercial vehicles also failed to advance. Hybridbuses as a new energy vehicles, regardless of changes from its power source, it is theobjective requirements of energy saving, the traditional hydraulic power steeringsystem defects, are no longer appropriate choice of new energy vehicles. Currently,research on commercial vehicles in the EPS system is already in progress, it isforeseeable hybrid buses EPS system must have broad application prospects.This article describes the development process of automotive steering systemsand different steering system works. Describes the advantages of EPS system, alsointroduced the development of EPS system at home and abroad. For the characteristicsof the car, the program of integral arrangement is designed of EPS system and selectthe type of the key components of the torque sensor, a speed reduction mechanism, aelectromotor etc. EPS systems on three common booster characteristic curves wereanalyzed by the power characteristics of the power system design target current fuzzycontroller. EPS system control mode and several commonly used control algorithmsare discussed, PID control and fuzzy control selected under power control mode as athesis research. EPS system is complex, appropriately simplified, mathematical modelof EPS system. Under the power control mode, based on PID control and fuzzy controlestablished simulation model of EPS system and its subsystems in MATLAB/Simulink.The simulation result indicated: the overshoot and the adjustment time of vehicleequipped with EPS had been remarkably improved, which proved that EPS system canimprove vehicle’s handling stability and steering easiness. Compare to PID controlstrategy, fuzzy control strategy had the merits of faster response.