Takayuki Usuda

Contact force control of an active pantograph for high speed trains

In this paper, a mathematical model of the pantograph with flexibility is developed based on experiments, and then an optimal controller together with a sliding observer is proposed to regulate the contact force in the presence of variation with respect to the equivalent stiffness of the catenary system. Furthermore, some physical interpretations of the closed-loop dynamics and pole-zero cancelations are given by analysis from a viewpoint of the output zeroing.

Dynamically substructured testing of railway pantograph/catenary systems

This paper presents a methodology for testing railway pantograph/catenary systems based upon the dynamically substructured system approach for combined physical and numerical components, originally developed by Stoten and Hyde. The main advantage of the dynamically substructured system is that it can provide more stable substructured testing than alternative schemes, such as the commonly used hybrid simulation method, often referred to as hardware-in-the-loop simulation. The developed method is validated through experiments using a simple pantograph rig, together with a numerical simulation of the catenary. In order to realise a real-time simulation of the large catenary model, for the first time in dynamically substructured system testing this study uses (i) a modal analysis technique to reduce the dimension of the contact wire model and (ii) a moving window approach to represent long-distance travel of the pantograph. Finally, the experimental dynamically substructured system test results are compared with simulations of the benchmark pantograph/catenary emulated system.

Reduction of Aerodynamic Noise Emitted from Pantograph by Appropriate Aerodynamic Interference Around Pantograph Head Support

Reduction of aerodynamic noise emitted from a pantograph head and its support is one of the important subjects for the speed-up of high-speed trains from an environmental point of view. In this study, to reduce aerodynamic noise emitted from the pantograph head and its support, suitable arrangement of a pantograph head which has a smooth cross section profile, was investigated. The flow field measurement in the wake domain of the pantograph shows that turbulent intensity can be reduced by setting the pantograph head at a suitable position. The reduction of turbulence in the wake domain is caused by appropriate aerodynamic interference between the pantograph head and its support. Furthermore, the results of the aerodynamic noise measurement show that the suitable pantograph head arrangement efficiently reduces aerodynamic noise.