Design And Realization Of Electric Power Steering Controller For All - Terrain Vehicle Based On

All-Terrain Vehicle(ATV) is widely used in forest fire fighting,exploration and military fields because of its good off-road performance.low cost and small environmental hazard.ATV traveling roads are often beaches,potholes, mountains and other complex pavements.also because of its large tire tread,wide and deep tire crown.make the friction between the tire and ground is large,increasing the operation difficulty and may affect driving safety.So the study of power steering system applies to ATV is very necessary.Compared to the Hydraulic Power Steering (HPS) and Electro-Hydraulic Power Steering (EHPS).Electric Power Steering(EPS) has a better assemble,lower energy consumption,green environmental protection and so on.It is a focus research in the world’s automotive steering field.Currently,the EPS power assistance motor is mainly permanent magnet brush DC motor,permanent magnet brushless DC motor and Permanent Magnet Synchronous Motors (PMSM).Compared to permanent magnet brush DC motor,PMSM has no carbon brushes,bigger power volume ratio,lower price, etc.,compared to the permanent magnet brushless DC motor,smaller torque ripple,better control performance.So this paper will design a EPS controller for ATV based on PMSM.First of all.this Paper establishes the PMSM control model.Due to its nonlinear, strong coupling and time-varying characteristics,the paper will study and analyze the PMSM control strategy,and decide to use the vector control method.In the design of PMSM variable frequency driving,the paper introduces in detail the principle of Space Vector Pulse Width Modulation (SVPWM) and the algorithm implementation,also designs the control structure of EPS system.And then this paper designs the hardware and software components of the controller.The hardware part use the MC56F82748 as core,mainly includes power supply module,DSP minimal system,current sampling module,torque sampling module,speed sampling module,engine speed sampling module,motor rotor position measuring module,drive isolation module,three-phase inverter and the fault indicator module.The software part designs the software flow chart of the system,its subsystem mainly includes the assistance characteristics curve design,PMSM rotor position decoding design,PI controller design and SVPWM control algorithm design.Finally, in order to verify the basic functionality,its performance and reliability of the controller.this paper conducts bench experiment and the real vehicle experiment. Experimental results show that the designed controller has power assistance functio-n,a good power assistance feeling.can realize power assistance with speed and fault-tolerant control,designs the cooling part at the same time, meets the requirement of the controller in this paper.