| dc.description.abstract | This thesis analyses a general case of the vibration isolation (VI) problem, considering both a rigid and non-rigid supporting structures. The aim is to study changes on the behaviour of both systems isolators and supporting structure when the interaction phenomenon between them is considered. The influence of the VI task on the base response is evaluated. In addition, the effect of the base dynamics on the the VI and alignment problem is studied. The novel contribution to the knowledge of this thesis is formulation of a novel VI approach, which facilitates a holistic analysis of the problem considering all the systems involved on it. This approach is valid for any number of isolators and for any type of base structure. Moreover, different control objectives can be easily defined; evaluation of the interaction phenomenon on both the platform and base response for different VI techniques; demonstration of the importance of the isolator damping ratio on the influence that the VI task has on the base response; evaluation of the effects of the supporting structure dynamics on the VI and alignment problem when multiple isolators are involved; analysis of the Multiple-Input-Multiple-Ouput (MIMO) control strategy by comparison with the Single-Input-Single-Output (SISO) control strategy. This comparative has been made for the VI and alignment problem of multiple isolators on a non-rigid supporting structure and includes analysis of the effectiveness of the Coral Reefs Optimization algorithms to find nearly-optimal control gains in VI and alignment problems. Through the investigation made for this thesis, a number of significant results have been reached, which show the importance of the supporting structure dynamics on the VI and alignment task. Moreover, the interaction phenomenon, and its consequence on the base response, has been investigated experimentally. The results derived from this thesis conclude that, for most scenarios, the dynamics of the base affects the VI task. Also, the active VI (AVI) technique shows a greater influence on the base response than passive VI (PVI) technique, for most cases. It has been observed that the use of AVI technique can additionally be oriented to control vibrations of the supporting structure, while the VI task is developed. Significant differences have been found when multiple isolators are involved in the same task for the alignment and VI problem, depending on whether or not the dynamics of the base are considered. The best set of control gains for the rigid-support case (which lead to maximum damping ratio) differ from those obtained when the supporting structure is considered as a flexible system, for different cases analysed in this thesis. The MIMO control strategy has shown great improvement with respect to the use of the SISO control strategy. Also, the Coral Reefs Optimization algorithms have been demonstrated to be a suitable tool to find nearly-optimal solutions for this type of problems. | en_GB |
