Motion Of Pantograph Research Articles

The Construction Parameter Optimization of High-Speed Pantograph

The composition structure of high-speed pantograph is analyzed, which is transformed into a four-rod mechanism, and the relative motion relation and its position coordinate equations are built by constructing a kinematics model. Based on the equations of motion of pantograph and the simulation of motion pattern between elevation height and transverse deviation of bow head, angle of balance arm is obtained by programming and running program in Matlab. The main parameters which are affecting high-speed pantograph lateral offset and balance arm rotation angle are analyzed. The relevant parameters are optimized by using the sequential quadratic programming (SQP) algorithm in Matlab. We compare the results after optimization with the results before optimization. Finally, according to the optimized results, the pantograph is modeled in Solidworks. The pantograph model is imported into the finite element analysis software to load, and the displacement cloud diagram of the pantograph bow head is obtained, and compared with the theoretical value to verify the optimization results.

Novel analysis methods of dynamic properties for vehicle pantographs

Transmission of electrical energy from a catenary system to traction units must be safe and reliable especially for high speed trains. Modern pantographs have to meet these requirements. Pantographs are subjected to several forces acting on their structural elements. These forces come from pantograph drive, inertia forces, aerodynamic effects, vibration of traction units etc. Modern approach to static and dynamic analysis should take into account: mass distribution of particular parts, physical properties of used materials, kinematic joints character at mechanical nodes, nonlinear parameters of kinematic joints, defining different parametric waveforms of forces and torques, and numerical dynamic simulation coupled with FEM calculations. In this work methods for the formulation of the governing equations of motion are presented. Some of these methods are more suitable for automated computer implementation. The novel computer methods recommended for static and dynamic analysis of pantographs are presented. Possibilities of dynamic analysis using CAD and CAE computer software are described. Original results are also presented. Conclusions related to dynamic properties of pantographs are included. Chapter 2 presents the methods used for formulation of the equation of pantograph motion. Chapter 3 is devoted to modelling of forces in multibody systems. In chapter 4 the selected computer tools for dynamic analysis are described. Chapter 5 shows the possibility of FEM analysis coupled with dynamic simulation. In chapter 6 the summary of this work is presented.

LabVIEW application for motion tracking using USB camera

The technical state of the contact line and also the additional equipment in electric rail transport is very important for realizing the repairing and maintenance of the contact line. During its functioning, the pantograph motion must stay in standard limits. Present paper proposes a LabVIEW application which is able to track in real time the motion of a laboratory pantograph and also to acquire the tracking images. An USB webcam connected to a computer acquires the desired images. The laboratory pantograph contains an automatic system which simulates the real motion. The tracking parameters are the horizontally motion (zigzag) and the vertically motion which can be studied in separate diagrams. The LabVIEW application requires appropriate tool-kits for vision development. Therefore the paper describes the subroutines that are especially programmed for real-time image acquisition and also for data processing.

Vibration of a discrete-continuous structure under moving load with one or two contact points

What is of particular importance in view of the development and operation of fast railway transport is the overhead system vibration excited by pantograph motion. The problems discussed in the paper are related to continuous system vibration under moving loads. Modelling the catenary-pantograph system is connected with motion of two subsystems, namely: continuous (contact wire) and discrete (pantograph). In the paper, the results of research on dynamical phenomena caused by the interaction between the pantograph and catenary are presented. The stiffness of the catenary wire is taken into account. The dynamical phenomena occurring in the system are described by a set of partial and ordinary differential equations. The solution to these equations has been obtained using approximate numerical methods.

A Test Study on Interface Dynamics of Current Collection System in High Speed Trains

Using a test run data, the dynamics of the interface between the catenary and pantograph constituting the current collection system in high-speed trains are investigated. The test run signals are analyzed to determine the dynamic parameters critical to the current collection performance. There are found to be frequency components of the pantograph motion that are dependent on train speed as well as components that are stationary such as the resonant mode of the panhead suspension in the pantograph. From contact force measurement using load cell, the mean contact force was found to be stable while the fluctuating component was found to be dependent on the range of the frequency of the pantograph motion taken into account. The finding implies that numerical investigations reported in the literature that are based on lumped element models of the catenary and/or pantograph provide accurate predictions on the mean value but are of limited use in estimating fluctuation of the contact force. It is concluded that simulation studies based on lumped-element models which do not incorporate panhead structural vibration modes is inaccurate at high train speeds.

An experimental study of the dynamic characteristics of the catenary-pantograph interface in high speed trains

The dynamic characteristics of the catenary-pantograph interface in high-speed trains are evaluated. During a test run signals from accelerometers, load cells, and strain gauges attached to various parts of the pantograph assembly are collected and processed. The signals are analyzed in both the time and frequency domains to determine the dynamic characteristics of the catenary-pantograph interface constituting the critical part of the current collection system of the high-speed train. It is found that there are major frequency components of the pantograph motion at the interface that shift in direct proportion to the train speed as well as components that are stationary in the frequency domain such as the 8.5 Hz component representing the fundamental resonant mode of the panhead assembly. The contact force at the interface shows that while the mean contact force stays almost invariant, the fluctuating component is significantly dependent on the filtering frequency applied to the accelerometer signal during estimation of the inertia force of the panhead. An important implication of the finding is that analytical or numerical investigations based on lumped element models of the pantograph may provide accurate predictions on mean values of the contact force at the catenary-pantograph interface, but are inherently limited in estimating high-frequency fluctuations in the contact force. Since the ratio of the fluctuating portion to the steady-state portion (i.e., the mean value) increases with increased train speed, the predictive capacity of the investigations based on numerical simulations diminishes with increasing train speed.

Pantograph motion on a nearly uniform railway overhead line

Representing the line by a tensioned string supported by an elastic medium, whose spring constant varies periodically with position by a small amount, a mathematical investigation is made into the oscillations of overhead equipment produced by the passage of a pantograph. The simplicity of the representation allows analytical results to be obtained for a pantograph whose impedance is of quite general type. For the pantograph in current use, the analysis shows how the oscillations increase at certain critical speeds and how these speeds, and the magnitude of the oscillations, depend on the parameters of the pantograph/line combination.

Discussion on “Dynamic model studies of overhead equipment for electric railway traction” and “Pantograph motion on a nearly uniform railway overhead line”

Discussion on “Dynamic model studies of overhead equipment for electric railway traction” and “Pantograph motion on a nearly uniform railway overhead line”