Research On Traction And Adhesion Control For High Speed Train Based On Force Observer

Under these objective conditions including the wide scale of china high-speed railway network and the complex situation about the geology, the terrain and the climate along the railway, the train operating environment becomes rather complex with the running speed of modern high-speed trains (HST) increasing. Ensuring safe and smooth operation of the HST under the high-speed and long-range condition, essentially depends on the mechanism, the changing process, the interaction and the control effect of these various forces acting on the HST.This paper is divided into the following sections:Firstly, we take the force analysis of the HST and research the wheel-rail adhesion basic theory. These causes, components and factors about the traction, braking, running resistance acting on the HST are described in detail.the process, properties and main affecting factors about the wheel-rail adhesion are analyzed in the paragraph.Secondly, the unit-shift-multi-particle longitudinal dynamics model of the HST and the three-dimensional mathematical model including the impact from the running speed of the wheel-rail adhesion are established. These models match the actual operating conditions better, because they take those factors such as the internal force, the running resistance, the wheel-rail cushion effect and other nonlinear elements into account. A traction control method based on force observer is proposed. Two schemes which are respectively based on the double force observer and the resultant force observer are discussed. The basic principle of this method is described as follow:We get some estimated force data from the adhesion force observer, the disturbing force observer and the resultant force observer which are based on the principle of the disturbance observer. It forms a closed-loop control in the force level by introducing these estimated force data into the control process. The top-level adhesion command meets the traction control requirements and the bottom-level adhesion force is implemented by directive. This method achieves the goal that the target speed curve is tracked accurately under the influence of some disturbances such as nonlinear resistance, uncertain carriage forces and time-varying wheel-rail surface conditions.In the adhesion control study, we propose a novel active adhesion control method based on the axial dynamics model. The basic principle of this method is described as follow:The adhesion torque is estimated from an adhesion torque observer based on the principle of the full-dimensional state observer. The real-time adaptive limit torque which is calculated by the estimated adhesion torque and the variable step size algorithm monitors the traction motor torque on line. In contrast to the past adhesion control, this proposed method need not detect the actual wheel-rail information and the vehicle speed. It is able to take the advance prevention rather than later compensation to achieve good active adhesion control. For the difficult problem about the low adhesion mutation, this method can suppress skid phenomenon quickly and realize the maximizing adhesion utilization after the system recovers to the steady stateThe above programs are verified to be effective by contrastive simulations in the matlab/simulink environment. Finally, we summarize the whole work in this paper and point out the recommendations in the further research work.