The Study On Steering Control Technology Of Independent Rotating Wheels Based On UM

With the continuous development and progress of society and the increase of the urban population size,traffic jam and automobile exhaust pollution are becoming more and more serious.Meanwhile,people pay more attention to the problems of energy and transportation,and the concept of environmental protection is widely accepted.It’s different from traditional transportation that 100% low-floor vehicles’ advantages include capacity,convenience and environmental protection and so on.By this way,100% low-floor vehicles are applied and promoted in many cities.It is widely known that to achieve the requirement of low floor,it is necessary to decouple the left and right wheels of the wheelset to reduce the height of the axle.For two independent rotating wheels,how to make them have the ability of active guidance has become a hot and difficult problem in recent years.Firstly,the paper,approaching the topic by creep force and gravity restoring force,the most important part in the wheel-rail relationship,analyzes the root causes that traditional wheelsets can achieve self steering,but independent wheels can’t.At the same time,by using the differential equation of wheelset motion and obtaining the characteristic polynomial,the paper analyzes difference between the two wheelsets,getting the result that the independent wheel can not guide is verified from the mathematical point of view.Secondly,in the preprocessing of UM multi-body dynamics software,the paper establishes the wheelset and bogie models,analyzing the reset ability of straight road section and the safe passing ability of curve road section.The results show that the independent wheels and the bogies with independent wheels have no guiding ability,and they can’t return to the track center line when they are deflected by the excitation during operation.Moreover,when they pass through the curve section,the rim of the independent wheels and the rail are easy to contact,resulting in the wheel set running according to the rim guidance.Safety and stability are seriously affected.Thirdly,the paper analyzes the principle and method of independent wheel active guidance,deriving the control objectives of straight road and curve road are respectively.When running on the straight road,the input end of the control system is the angular speed of the wheel,and then through the proportional control in the PID controller,the shaking moment is calculated to make the wheelset center.When running on the curve road,in addition to the angular speed of the wheel,the input of the control system also includes the running speed of the train and the curvature change of the curve.Then,through the proportional control in the PID controller,the shaking moment is calculated to make the wheelset produce the appropriate angle of attack and pass the curve section.Moreover,the paper introduces the composition of the control system and the related detection system applied in reality,which proves the feasibility of the method.Finally,the paper introduces the control process of the guidance system,and analyzes how the control system makes the vehicle realize the function of straight-line alignment and the function of safely passing through the curve.Finally,the UM model of the vehicle is established,and it is verified that the independent wheelset vehicle has no steering ability.Then,according to the method and principle of steering control,the Simulink steering control model is established,and it is co simulated with the UM model of vehicle.The steering control model enables the independent wheelset vehicle to return to the track center line when it deviates from the straight road section,passing through the curve section safely and smoothly.which proves that the steering control system is feasible.These two cases prove that the guidance control system is feasible.