Structure Design And Experimental Research Of Steering By Wire Device In Electric Vehicle

Due to the rapid development of the contemporary automotive industry,the requirements for vehicle stability and reliability are became more important,and one of the most important systems in the car: the steering system is also rapidly developing,and the Steering by Wire(SBW)system is become main emerging target for the development of new era automobiles.The elimination of the mechanical components between the steering wheel and the front steering wheel in the system breaks the shackles of the traditional steering system and enables better steering and control.Now many scholars are actively researching.In this paper,the following work is mainly done for its steering by wire system:(1)Based on previous studies,this paper designs a device that uses a rotating magneto-rheological damper to provide road simulation,redesigns and determines parameters for a rotating magneto-rheological damper,and using permanent magnets.The static magnetic field and the dynamic magnetic field of the exciting coil superimpose to provide the damping torque of the driver’s road sensation,and the relationship between the torque and the magneto-induced stress under the action of the permanent magnet and the exciting coil is deduced,and then the road simulating device is simulated.The working principle,structuralparameters,material selection,magnetic circuit design were studied and analyzed.Finally,the ANSYS magnetic field analysis was performed on this kind of road simulating device,and the parameters of the selected initial parameters were optimized with the simulated annealing algorithm.It laid the foundation for the smooth progress of the next chapter.(2)Based on the two-degree-of-freedom vehicle model,the yaw rate and the centroid slip angle are transformed by the Laplace transformation at the fixed gear ratio and the ideal gear ratio,and the yaw rate and the centroid lateral deviation under the two transmission ratios are deduced.The transfer function of the angle to the steering wheel angle,and the yaw rate and the slip angle of the center of mass as the evaluation criteria,studied the yaw rate and the centroid slip angle at different speeds under variable gear ratios and fixed gear ratios.In the ideal transmission ratio,its stability can be better and more stable.(3)Study the damping torque control and the stability control of the corner of the road simulator.The stability of the rotation angle is studied.Firstly the sliding mode control law based on corner stability control is deduced and the Simulink model is established.The comparison between PID control and sliding mode control shows that the sliding mode controller is more stable.The relationship between current and damping torque of the road-simulating device was deduced,then the PID-controlled Simulink model was established,and the best PID threeparameters were selected to track the feedback torque.Finally,the experimental scheme of the steering by wire system was designed.The road simulator was selected and the main components of the test bench were selected.A reasonable selection was made.A traditional power steering system was built and the SBW system test bench scheme was established.(4)Finally,the experimental scheme of the steering by wire system was designed,the road simulating device and the main components of the test rig were selected and rationally selected.A conventional power steering system was built and the SBW system was implemented on the basis of it.Test bench design,Given the parameters to be tested,lay the foundation for further research later.