Study On Coupled Vibration And Control For Underframe Suspended Systems Of High Speed Trains

With the achievement of major breakthroughs of a number of key technologies under the strategy of introduction,digestion,absorption,and innovation,the operating speed of China’s various types of high-speed EMUs has been gradually increasing.In order to ensure the operating safety and ride performance of high-speed trains,the vibrations between carbody and underframe equipment have been paid more and more attention.At present,the high-speed EMUs in China are all power distributed.The vehicle equipment is mainly suspended on the carbody underframe,such as the traction converter,and the auxiliary power supply devices.The masses of these equipment are ranging from tens of kilograms to several tons.When the vehicle is running at high speed,the elastic carbody and the underframe equipment are interacted through the suspension system,which results in coupled vibrations.Large mass equipment certainly has big impact on the carbody vibration.In order to reduce the carbody elastic vibration,and protect the important underframe equipment,it is highly necessary to study the coupled vibration between carbody and equipment,and the control strategy.Based on the theories of rigid flexible coupling dynamics and modal analysis,a three dimensional dynamic model of vehicle system with considering underframe equipment is established.The ride comfort and running safety of the vehicle system for the underframe equipment with rigid suspension and elastic suspension are analyzed and compared..The results show that,the dynamic performance of the vehicle with the equipment elastic suspended under the reasonable parameters is better than that with the equipment rigid suspended.Taking the fan as the research object,the influence of the unbalance mass of the active equipment on the vibration characteristics of the equipment and the carbody is analyzed by the method of field test incorporating with numerical simulation.It is found that dust cleaning can effectively reduce the vibration of rotating equipment,and the vibrations of the equipment and the car body increase with the increase of unbalance value.The double-layer vibration isolation system can effectively reduce the vertical vibration of the car body.Semi active control scheme is adopted for the suspension system of the equipment.Through the fuzzy control principle of the modified skyhook damping,the vibration characteristics of the vehicle system under harmonic excitation and random excitation are studied.The results show that compared with the traditional passive suspension,the semi-active control scheme can restrain the vehicle body vibration and improve the dynamic performance of the vehicle.By setting up a spring-damping device between the underframe equipment,and the different layout scheme of the equipment and the vibration characteristics of vehicle and equipment are investigated.The results show that the spring-damping device can reduce the lateral and vertical vibrations of the vehicle,and the effect for the lateral is more obvious.