Observer based control of an magnetorheological damper

Magnetorheological (MR) fluids enable the rapid and continuous alteration of flow resistance via the application of a magnetic field. This unique characteristic can be utilised to build semi-active dampers for a wide variety of vibration control systems, including structural, automotive, and bridge applications. However, the non-linear behaviour of smart fluid dampers makes the objective of achieving a desired control force very difficult. Most of the control algorithms proposed to overcome this problem require the measurement of both the MR damper force and the states of the system, which increases the complexity of the system. In this thesis, this problem is overcome by developing a non-linear observer. A further aim of this thesis is to investigate the effective control techniques for broadband excited observer-based MR vibration systems. Through an extensive series of numerical and experimental investigations, the general single-degree-of-freedom and tuned mass damper problems are presented. In an experimental case study, the hardware-inthe-loop-simulation method is adopted, which provides an excellent means to bridge the gap between theory and practice when the behaviour of a specific component is complex. Here, the vibration absorber with controllable MR damper is physically tested, whilst the remainder of the structure is simulated in real-time. The results demonstrate that the chosen control strategy can provide significant performance benefits when compared to more commonly used strategies and equivalent passive systems.