Application of Oil-Hydraulic Actuator for Active Suspension of Railway Vehicle. Investigation with Optimal Regulator Using a Scale Model on a Test Apparatus.

Active suspensions have been studied to improve the ride quality of railway vehicles. In many cases, pneumatic actuators were employed in those studies. This paper deals with the applicability of oil-hydraulic actuators that are expected to have more control on the running vibration for active suspension. This was examined experimentally with the optimal control theory using a 3 d. o. f. half-car scale model. The results show that the controllable frequency range extends with adequate control. Especially, in a case where the actuator properties were considered in the feedback gains, superior property of the vibration isolation was obtained in the middle frequency range of 3 Hz to 13Hz. Here, the selection of valve equivalent resistance is significant in feedback gains, because the actual valve resistance changes with oil flow passing through the servo valve. Some cases based on output feedback show more effctive results than the full-state feedback in the lower frequency range.