Abstract
The authors have been studying on the method for reduction in contact force fluctuation between catenary and pantograph using active control techniques. The active pantograph presented in this study has a pneumatic cylinder as an actuator, which is controlled to apply a control force to the lower frame of the pantograph so as to suppress the contact force fluctuation based on the impedance control methodology. The pneumatic actuator, however, shows a strong nonlinearity due to the flow characteristics of the flow valve, the friction at the cylinder, etc. This nonlinearity results in an error in the actuator force and degrades the control performance. This paper focuses on suppressing the influence of the nonlinearity on the relationship between command signal and generated force by means of pressure compensation of pneumatic cylinder. The differential pressure in the air cylinder is measured and fed back to the pressure compensator. The compensator calculates the difference between the measured differential pressure and the required one to generate the prescribed force and generates the command signal on the basis of the FED control law. The vibration test for the actively controlled pantograph shows that the contact force fluctuation is obviously suppressed by installing the pressure compensator.
