Research On The Inverse Identification Method Of Wheel-rail Force Based On Railway Vehicle’s Acceleration

There are many threats to the operating safety of vehicles due to the complex environmental state of high-speed trains in China.Wheel-rail contact force is the most direct and effective metric to evaluate the safety of vehicle operation.Therefore,it is particularly necessary to obtain the real time wheel-rail force.In this thesis,combining the characteristics of the current wheel-rail force measurement technologies,the inverse identification method(IIM)of wheel-rail force based on acceleration was studied by using the Kalman filter theory.The main works are as follows:(1)The basic theory of wheel-rail force IIM was introduced.According to the linear system theory,the time discretization method of the state space equation and the rules of the observability of the system were derived.Based on the linear minimum variance estimation theory,the Kalman filter equations were derived.And the emphasis was put on the real-time and optimal estimation characteristics of the filtering technique;(2)The IIM of the wheel-rail force was developed by using Kalman filter.Firstly,the load IIM of the single-input system was studied,including the design of filters,the feasibility analysis of the acceleration-based load inverse method,and the selection of filter parameters.Then,the load IIM was improved to the multi-input system.Finally,in a typical case of 9-DOF(degree-of-freedom)semi-bogie model,the wheel-rail force IIM was discussed and implemented after the detailed analysis of wheel-rail contact relationship and interaction forces.The results indicate that: With the proper filter parameters,both of the left and right vertical wheel forces can be estimated through the vertical and roll acceleration of the wheelset,and the lateral wheelset forces can be estimated by the lateral acceleration of the wheelset;(3)The acceleration-based IIM of the wheel-rail force was applied on a full-vehicle system.Firstly,the full-vehicle estimation models were established,including a 14-DOF model for wheelset lateral force estimation and a 17 DOF one for vertical wheel force estimation.Consequently,in order to obtain the acceleration data and the positions of the accelerometer for the estimation model,a dynamic model was established by SIMPACK.Finally,the estimation results were verified under three different excitations,including random track irregularities,wheel polygonal wear and wheel flat.The results indicate that: All wheel-rail forces can achieve satisfactory results in these cases.