Development of semi-active control system for hydraulic dampers

Hydraulic dampers are most widely used in the suspension system on trains and heavy vehicles. However, they su er from a major drawback resulting from the change in characteristics of this device at high frequency, i.e. the equivalent sti ness of the damper increases considerably at high frequency along with a substantial decrease in the equivalent damping. This e ect leads to increase in the transmitted force at high frequency excitations, which has a negative e ect on the ride quality. To mitigate this e ect, semi-active control strategies for hydraulic dampers have been developed and tested. This study evaluates the dynamic response of four semi-active control strategies as tested on a numerical model of a quarter-train system and an experimental setup to test the performance of a single hydraulic damper. Skyhook control strategy, which is most commonly used control strategy in order to enhance comfort, is used as a reference for comparison. Each control strategy is evaluated for its performance under di erent base excitations and RMS acceleration on the chassis is used as a performance evaluation criterion as it is the most commonly used parameter to evaluate comfort.