تجزیه و تحلیل حساسیت وضعیت سیستم پنتوگراف برای یک وسیله نقلیه راه آهن با سرعت بالا با توجه به طول دهانه و نیروی تعالی استاتیک

In this paper, dynamic characteristics analysis of catenary and pantograph systems for a high-speed rail vehicle is carried out. The catenary system is considered to be a beam model. The analysis of the catenary based on the finite element method (FEM) is performed to develop the pantograph. The stiffness value can be obtained at each nodal point on the contact wire. State sensitivity analysis was executed with respect to design variables considered by the pantograph system. The pantograph of linear spring–mass–damper system is considered as a 3dof model using lumped parameters. Dynamic modeling of the pantograph system is verified by actual experimental vibration data. To perform the sensitivity analysis, our study was considered lift force effect of the pan-head occurring at high-speed runs. Also, a span length and static uplift force were included into design variables. As a result, we could confirm that span length and plunger spring constant are some of the important design variables of catenary and the pantograph systems.

At present, the high-speed railway that is the next generation of transportation system is characterized by high stability, high driving velocity, and ride comfort as compared to the other transportation systems. An accompanying problem of the high speed of the railway is ensuring stable current collection. For stable operation of a railway, the catenary must be supplied with stable electrical power through solid contact with the pantograph. When the railway speed is increased, contact loss will occur between the pantograph and the catenary due to the catenary stiffness. In addition, wear on the pantograph is going to grow as electrical shock and damage may occur [1]. Therefore, research into understanding the current-collecting system's dynamic characteristics and the decreasing width of dynamic variation are needed. Progress has been made in recent research assuring the ability of high-speed driving as the basic technology of a high-speed railway [2]. The dynamic interaction of catenary and pantograph systems has been investigated extensively. Ockendon and Taylor [3] described an approximate analytical formulation to determine contact force between a contact wire and a pantograph. Manabe [4] conducted research on wave analyses to study the response between the pantograph and the catenary with discrete support springs. Wu and Brennan [5] investigated the dynamic relation between the catenary and the pantograph using finite element method (FEM). Vinayagalingam [6] studied contact force variation and pan-head trajectory by using finite difference methods. Today's situation is that an active pantograph is proposed for more stable current collection through maximizing the ability of the pantograph to follow the catenary [7], [8] and [9]. To improve the performance of the pantograph, its dynamics should be considered more precisely before applying an active system. Especially, many researchers trying to improve the system performance, have suggested using sensitivity analysis as an efficient tool for checking variations in design variables based on its dynamics. Vanderplaats and Arora [10] and [11] found that sensitivity information can be used as a design basis when re-designing a system. Haug et al. [3] investigated dynamic sensitivity analysis which is utilized for variation evaluation of mechanisms in the dynamic state. Jang and Han [12] devised a way to conduct dynamic sensitivity analysis for studying state sensitivity information with respect to changes in design variables. Sensitivity analysis about the pantograph system can be a useful tool to improve dynamic characteristics of a pantograph. In this study, the dynamic characteristics of a catenary system and pantograph supplying electrical power to high-speed trains are investigated. The analytical model of a catenary and a pantograph is composed to simulate the behavior of an actual system. To obtain the model of the catenary system for high-speed operation, we perform the analysis of the catenary system using FEM. The pantograph system is assumed to be a 3dof model using lumped parameters. The reliability of the dynamic model is verified by the comparison of the excitation test with fast Fourier transform (FFT) of the actual system. State sensitivity analysis was executed with respect to design variables of the pantograph system. Uplift force increased by aerodynamic lift force affects displacement and contact forces occurring in between the catenary and the pantograph system directly. Therefore, the lift force data acquired from experiments are utilized for sensitivity analysis. From results of the sensitivity analysis, it is established that design variable is more significant for dynamic characteristics of pan-head at high speed.

In this paper, dynamic characteristics analysis of a catenary-pantograph system is performed. The catenary system is analyzed by FEM. The contact and the messenger wire were modeled as beams with bending stiffness and tension. Displacement of pan-head is the main factor for dynamic performance of pantograph, and it is related to contact force directly. So design variables that are related to vibration characteristics of pantograph through sensitivity information are discussed. The conclusions of this paper are as follows: 1. Using the FEM, stiffness value according to position of contact line in 1 span was calculated and this approximated as periodic functions. 2. 3 dof pantograph modeling is verified by experimental data obtained through vibration experiments and confirmed that natural frequency of the catenary-pantograph system is at the level of 10 rad/s. 3. As a result of sensitivity analysis, we now know that dominant design variables related to dynamic characteristics of the catenary-pantograph system are a span length L and plunger spring constant k2. 4. To minimize dynamic motion occurring at high-speed runs, the pantograph system insensibility to a span length and aerodynamic lift force effect need to develop.