Research On Modeling And Simulation Of Electric Power Steering System For Electric Forklift

Forklift is a kind of vehicles which can be used for loading and unloading.Electric forklift with its small size,good start performance,small noise pollution and other characteristics has been widely used,and EPS(electric power steering)system as a power steering system,is designed to reduce the operator's operating burden,so that the vehicle can be coordinated in accordance with the intended target to complete the steering function of the vehicle.Compared with the traditional steering system like mechanical steering system and hydraulic steering system,the electric power steering system has the characteristics of high operational flexibility,simple structure and high safety.Therefore,it is of great significance to research the electric power steering system of electric forklift.This thesis studied the electric power steering system of electric forklift from three aspects.Firstly,according to the factors that affect the torque provided by the motor in the forklift,the boosting characteristic curve based on the velocity,the steering wheel torque and the load is obtained.Then,the robust H_? controller of the EPS system based on models of EPS system and a two-degree-of-freedom forklift is designed to ensure the power steering characteristics and stability of the system.Finally,the genetic algorithm is used to optimize the parameters of the controller weighting function,which further improves the robust performance of the system.Combined with a forklift,MATLAB simulation analysis with different conditions and control methods is done and indicates that the robust controller based on genetic algorithm is effective on offering controlled steering aided-power,satisfactory road feeling and the operating portability as well as stability of the system.Besides,the robustness of the system and driving safety are improved.