Development of a semi active suspension for an off road vehicle

Resumen

Vehicle ride and handling requirements lead to suspensión design conflicts which can only be imperfectly resolved with conventional passive suspensions. Computer controlled suspensions offer on the contrary a wider actuation area and therefore increased design possibilities, since the damping curves can be dynamically modified and the compromise between ride comfort and vehicle handling ameliorated. while fully active suspensions can introduce energy into the system and henee provide continuous control up to a certain bandwidth level, it is at the expense of cost, complexity and power consumption. Semi-active suspensions fill the gap between their active and passive counterparts, since they act as fast time-varying passive dampers that intend to obtain a performance improvement cl ose to the fully active systems, with less cost and smaller power sources. These features have attracted the interest of industry and many researchers The research work presented in this thesis covers several areas of the develoçment of a semi-active suspensión for a single seater off-road racing car, including hardware design, both advanced model ing and experimental validation work, and eventually the design, implementation and testing of suspensión control strategies A lightweight vehicle, originally conceived for off-road car cross competitions, has been employed in the study. With the implementation of the controliable suspensión, improving body attitude and reducing wheel hop were the main targets of the research accomplished, where hydraulic, electromechanic, and control issues play an essential role on the overall performance of the suspensión.