Date of Award
Master of Science
The use of an active component in an automotive suspension to enhance the overall performance by overcoming the compromises between conflicting demands such as passenger comfort and road handling has been the focus of researchers for many decades. The main objective of this research is two-fold: the first objective is to assess the benefits of using advanced control methods for the design of active suspension systems: the second objective is to investigate a relatively new concept of active infinitely variable natural frequency IVNF pneumatic suspension design. The active IVNF suspension has the ability to infinitely vary the natural frequency that allows it to achieve superior performance over contemporary suspension systems. In order to assess the effectiveness of various controller designs, a quarter car suspension model from existing litersture is used. Three different control designs (PI, LQG, and H[subscript infinity]) are compared for stability, performance and robustness. It is shown that the advanced H[subscript infinity] control design methodology yields a superior controller that has significantly better stability and performance robustness as compared to classical designs that are currently in use. The novel concept of using an active pneumatic suspension system that has an infinitely variable natural frequency is thoroughly investigated. A complete non-linear analytical model for a quarter car active IVNF pneumatic suspension system is obtained. The two candidate controller designs, LQG and H[subscript infinity], are used to design robust controllers for the nominal Linearized model derived for this system. A thorough investigation is performed to assess the technical viability of using active IVNF pneumatic suspension system, which uses active control designed using advanced control design methodologies. The simulation results demonstrate that implementation of an active IVNF pneumatic suspension system is indeed possible. The successful experimental validation of simulation results has a potential to revolutionize the future generation of vehicle suspension systems. The continued research will primarily focus on experimental validation of the results obtained in this thesis.
Porumamilla, Hemanth, "Modeling and control of active automobile suspension" (2003). Retrospective Theses and Dissertations. 19543.