The Study On The Control System Of Auto Electronic Power Steering Based On DSP

The auto electric power steering system (EPS) is the potential trend of the automobile power steering, and it is the technical breakthrough on the automobile steering technology next to the hydraulic power steering system. EPS has a lot of advantage over the past steering system, so that it becomes the hottest topic in the research field of the automobile steering in recent years.The reseach ideas of this paper is: uses the characteristic of the motor's torque held at a constant pressure varies directly with the motor's electric current and applies the method of controlling the armature current to control the power steering.Take the signal surveyed by the torque sensor of the steering wheel and vehicle's speed to controller's SCM, then bases on the memory's"torque——power steering's aim current",confirm the power steering'aim curren. then take the aim current to the motor.And then Samplings the motor's electric current by the the sample resistance, compares the actual electric current with the motor's aim electric current, uses the blur PID mixture contoller to accommodate, outputs the PWM signal to the drive circuit, carry through the power steering. The blur PID mixture adjuster make the error between the aim electric current and the actual electric current decrease as soon as possible, makes the system stabilization.Bases on the reseach ideas,this paper makes the following research work:1. The hardware's core is TMS320LF2406DSP, accomplishes the work of control and drive the perform organ of power steering system—BLDCM. (three phase brushless DC motor)Controling and driving the BLDCM is using the 2406DSP's PWM function produces PWM impulse to drive the motor.Using six same MOS composes the three phase bridge drive circuit.The MOS's base drive circuit applies the expert grid integrate circuit IR2130, in this way makes the hardware circuit predigestion, improves the hardware's reliability. At the same time bases on the chatacteristic of the DSP, desiges the collection interface circuit of the torque,vehicle speed feedback current.2. Power steering system is a close loop servocontrol system.Firstly basing the chatacteristic curve of the power steering confirms outport aim torque of the motor,...