Abstract:

A non-linear system model is established which considering the time delay effect of the CDC systems based on experimental tests and data analysis for the CDC shock absorber prototype developed for a high-class passenger vehicle. Two modes of the CDC shock absorber， respectively with one and two solenoid valves， are investigated. Fully considering complex and changeable operating conditions of vehicle and nonlinear factors， including possible suspension bump stops impacting， and lost contact of tires in severe road excitations conditions etc.， the influence of the time delay in shock absorber systems on vehicle performance is studied based on the established non-linear vehicle system modal and non-linear system simulation under different excitation levels. Combined with the optimization results based on NSGA-II algorithm， a modified skyhook control algorithm is designed and employed to analyze and compare the performance of vehicles with single and double valve shock absorbers. The study results show that， by using the designed optimal skyhook algorithm， better control effect and adaptive capability to CDC system delay can be achieved by the double-valve configuration compared with that single-valve configuration. The research results can provide valuable guidance for the design and improvement of independently-developed shock absorbers and provide crucial insights into the design of control algorithms for CDC semi-active suspension systems.

Key words: CDC shock absorber, system time delay, control valve scheme comparison, improved control algorithm, nonlinear modeling and simulation