Study In Theory And Application Of Pantograph Nonlinear Dynamics

Pantograph is one of the key components for train’s power supply, set in complex mechanical environment, suffering loads and constraints coming from the base and contact wire. It’s also in complex pneumatic and electromagnetic environment. Pantograph is usually designed as link mechanism with geometric non-linear characteristics, adapting to the complex line conditions through changing the relative position of each part.In order to describe the dynamic behavior of the pantograph accurately in pantograph-catenary interaction, relative coordinate methods are applied, and nonlinear dynamic equations are established concerning various factors. This paper is organized as follows:(1) Multi-rigid-body math model of pantograph are derived in detail based on relative coordinates methods, and the results are compared to commercial software Recurdyn while static and dynamic loads acting on pan head respectively.(2) To study current collection quality, nonlinear dynamic model based on relative coordinates methods is applied to pantograph-catenary interaction. Newton Euler equations of pantograph’s main components (upper frame, link, lower arm) are established and dynamic hinges constraint forces are solved. The main dynamic loads of key components of pantograph are calculated based on d Alembert principle. And load transfer characteristics through pantograph are analyzed in detail.(3) Pantograph’s differential equations concerning the motion of pantograph base are established and applied. Influences of train’s vertical vibration on current transmission quality of pantograph-catenary system are analyzed, so as the influences of train’s longitudinal acceleration in both open and closed direction of pantograph.(4) Pantograph’s differential equations adjusting to bracket with double strips are studied, which could release the nod DOF of pan head. Differences between single DOF mass spring system and bracket with double strips are discussed in pantograph-catenary interaction.(5) With the introduction of finite segment methods in flexible multibody dynamics, upper frame is discrete and n degrees of freedom numerical model of pantograph is proposed. Influences of the flexible upper frame on pantograph-catenary interaction are simply analyzed.Studies have shown that:relative coordinate methods can be used to describe the nonlinear dynamic behavior of pantograph, which can be applied to co-simulation of pantograph-catenary system concerning a variety of factors, including simulation of train-pantograph-catenary concerning motion of pan base (vehicle body vibration), simulation considering pan head as bracket-double strips model, and simulation considering the flexibility of upper frame. Pantograph models based on relative coordinates method have practical value.