Electric Buses Electronically Controlled Hydraulic Power Steering Controller Development

The trend of modern automotive technology is energy-saving,environmentalprotection and safety in today’s world.With the advantages of energy-saving&environmental protection,pure electric bus has become the attention focus ofgovernment and society.At present,the electric bus developed commonly use thehydraulic power steering system without any electronic control unit,whichmeans the waste of energy and is not good for improving the drivingcondition.In order to adapt to the requirements of energy saving andenvironmental protection of electric bus,the electronic hydraulic powersteering(EHPS) is developed in this paper.Firstly,the whole frame structure and working principle of electric controlsystem was determined.The suitable components for the system wereselected,mainly the steering wheel angle sensor and assist motor.On thisbasis,the structural characteristic,operating principle and driving principle of theDC brushless motor were emphasized.Then,the control strategy was developed for the system.Beginning with the request for boosting characteristic,the goal motor speed was analyzed atdifferent vehicle speed and steering wheel speed when satisfying the best driverhand force.Then,through the research of motor speed control method,the dualloop serial speed control method were determined,making the system better torespond to the changing speed of the target,so as to provide appropriateassistance.Hardware and software were designed for the system by according to theworking principle of electric control,and the corresponding design process aredescribed in detail.Finally,by connected with the computer,the ECU was debug and the mainfunction of motor speed control was tested,the result showed that the ECU canoperate normally and the motor speed can follow well.