Optimization Of Electric Hydraulic Power Steering Control System For The Pure Electric Bus Of Model A

Pure electric bus has been widely used because of its energy saving,environmental protection and many other advantages.A company has produced pure electric buses of model A based on 17 diesel buses.The bus adopt the flow of electric hydraulic power steering system,and the motor is running at 1650r/min speed under various working conditions.In the process of using,it is neither energy saving nor easy to improve steering control performance.Aiming at the above problems,this paper studies the improvement of the electric hydraulic power steering system,so as to improve the energy saving of the steering system of the pure electric bus of model A,and make it reach the good control request.The main research works are as follows:1.The EHPS system of the pure electric bus of model A was improved,and the EHPS system controller and steering wheel angle sensor were added on the basis of the original EHPS system.When the system was working,it could realize the speed control of the hydraulic pump drive motor,so as to save power consumption,improved power performance,and enhanced the steering control performance.2.The hardware and software scheme of new control system for the EHPS system were Designed according to the improvement plan,which includes the minimum system with the MC9S12XDT256 chip,CAN communication module,power supply module and steering wheel angle sensor selection of the selection and design work.3.According to the basic parameters of the electric bus of model A and vehicle test results,the vehicle model was built with seven degrees of freedom based on Matlab/Simulink.Based on the model was established the electric bus of model A steering resistance moment and steering wheel angle,speed,analyzed the electric bus of model A EHPS series hydraulic system characteristics,established the relationship between the motor speed and steering torque,designed the ideal steering torque curve,and established the MAP assist characteristic diagram of the pure electric bus of model A EHPS system for steering and turning back.4.the combined simulation model of EHPS system was Established that based on the AMESim and Simulink,and carried on simulation test with response,following and steering stability of the motor,the improved steering system’s steering handiness,the working process of the power assisted system and step steering,as well as the energy saving of the improved EHPS system were simulated.The simulation results show that improved EHPS system of the electric bus of model A has good responsiveness,following and stability.The EHPS system turns to lightweight with the requirement of the designing road sense,the system works well during step steering and the power consumption of brushless DC motor is reduced by 22% compared with the original system under the condition of single city cycle.