Study On Semi-Active Suspension Control Strategy Of High-Speed Vehicles

In recent years,with the rapid development of China’s high-speed railways,China has become a country with the highest speed,the largest scale,and the most abundant and complex high-speed railway operation.Vehicle operating range and operating conditions are gradually diversified and complex,resulting in cross-line,cross-regional long-term operation,and other burgeoning needs,which puts forward higher standards and requirements of the related supporting key technologies for high-speed vehicles.The design,construction,operation,maintenance standards,and the natural environment of each high-speed railway line are different,resulting in apparent discrepancies in the external conditions,including rail surface and track unevenness incentive.The current passive suspensions of high-speed vehicles are designed to consider multiple factors under the compromise optimal parameters,which cannot effectively adapt to different boundary conditions,and it is difficult to meet the cross-line and cross-regional operations.Therefore,using semi-active suspension technologies to improve the vehicle’s ride comfort has important engineering practical significance.Based on this perspective,taking the semi-active suspension system of highspeed vehicles as the research object,and improving the random vibration and hunting motion of carbody as the research objective,the following main research work is carried out of:(1)The dynamic model of high-speed vehicle with semi-active suspensions is established,which considers the nonlinear wheel-rail contact relationship and the nonlinear suspension characteristics.The semi-active damper is valve-driven type in which the working characteristics of each valve and the flow relationship of each chamber are considered.The dynamic model of vehicle system with semi-active suspension is verified through relevant test data,and the joint simulation platform of the high-speed vehicle with semi-active suspension is built based on the model.(2)Based on the valve-driven semi-active dampers,the secondary lateral semi-active suspension control system is designed and mounted on the real vehicle to conduct roller rig and field tests,and the control strategies are designed for carbody vibration controls.A time lag compensation scheme based on the vibration amplitude is proposed,and the test results are compared with those obtained from the joint simulation platform so as to verify the reliability of the simulation platform,which lays the foundation for the subsequent development of control strategies based on the joint simulation platform.(3)The influence law of the key parameters of the skyhook damping control strategy on the vibration control of the carbody is analyzed,the control characteristics of different damping control strategies are discussed.A control strategy adjustment algorithm with the conversion frequency identification and an improved hybrid damping control strategy are proposed.The fuzzy hybrid damping control strategy is proposed to take into account the vibrations of the carbody and the bogie frame on different line operation,and its effectiveness is verified.(4)By analyzing the field measurement data of the carbody hunting motion,the vibration characteristics of the vehicle are summarized.A method for determining the carbody hunting instability based on the frequency domain amplitude of carbody lateral acceleration is proposed and verified using the field measurement data.The key influencing factors affecting the carbody hunting motion are studied.Three typical operating conditions that cause the hunting motion are summarized,the control effects of the state control strategy and the damping control strategy for the carbody and bogie frame under the carbody hunting motion are discussed,and the effectiveness of the control strategies are proved by line running adaptation analysis.