The inherent conflict between ride and handling in a conventional passive suspension system is extremely difficult to solve. As a result, a considerable amount of work has been carried out over the last thirty years in order to solve this problem. Through the marriage of mechanical, electrical and hydraulic components, a wide range of controllable suspension systems have been developed varying in cost, sophistication and effectiveness. They can be classified into four categories ? active suspensions, semi-active suspensions and active anti-roll bars. Among these systems semi-active suspensions have received considerable attention because of their low cost and competitive performance compared with their active alternatives. In many applications, semi-active suspensions are more suitable than active systems, particularly because of the simplicity of their application in existing systems and their low energy demands. Semi-active suspensions have found some applications in commercial production vehicles, though the market is still small. For example, the CDC (continuous damping control) system provided by ZF Sachs has been successfully applied on the Audi A8, the Opel/Vauxhall Astra and other vehicle models. Based on an existing passive hydro-pneumatic suspension unit, a semi-active suspension was designed and investigated through computer simulation in this research. A nonlinear suspension model was built upon a previous study and was investigated through quarter car analysis. Two modified skyhook controllers, a two-stage damping controller and a continuously adjustable damping controller were designed and a comparison study was carried out. This study demonstrated that semi-active suspensions could effectively improve the vehicle ride and handling with competitive cost. Better performance can be achieved with a continuously adjustable damper compared with its two-stage alternative. Practical issues such as signal processing and valve dynamics were considered in this study. It was shown that the necessary control feedbacks could be estimated from transducers already available without using extra sensors, provided that signal processing filters are properly designed. Though increased valve dynamics could improve the system performance the trade-off between cost and performance would require a compromise to be made in a practical application.
|Published - Nov 2006
|2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006 - Chicargo , USA United States
Duration: 5 Nov 2006 → 10 Nov 2006
|2006 ASME International Mechanical Engineering Congress and Exposition, IMECE2006
|USA United States
|5/11/06 → 10/11/06