چكيده به لاتين
The purpose of this thesis is a novel approach for choosing sliding surface in the variable structure control scheme. The literature review on this area shows that selecting the sliding manifold which has a significant influence on the performance of the closed-loop system has performed with an initial restriction on the structure of the sliding manifold. This initial limitation is in fact a designer’s exclusion from a degree of freedom which could help him in order to achieve a specific aim. In this thesis, such surfaces are named as specified-structure.
If the sliding surface is the output of a design process instead of having a predetermined structure, it will better provide the possibility of meeting the specific performance goals. In this thesis, such surfaces are named as unspecified-structure ones.
The subject of this thesis is associated with unspecified-structure surfaces. In better words, in this thesis in a level higher than specified-structure manifolds, a systematic approach has been proposed for extracting sliding manifold which has provided an accessing to a better performance for the multi-input stochastic systems. The present thesis has divided into several sections to achieve its goal. First, the gap in sliding mode area, both in terms of the studied systems and existing approach for selecting the sliding manifold has been expressed clearly and the necessity of using the new method has been described. Afterward, by selecting a definite performance index, a novel sliding manifold has been designed and its capability to local stabilizing the single-input deterministic systems has been proven. Then, with presenting some ideas, the ability to stabilizing the multi-input stochastic systems through the proposed sliding surface has been shown. Also, the advantages of the new method in the form of a ¼ car suspension system activation has been described and finally it has been used for control of a ½ car suspension system (as an example of multi-input stochastic systems) and its performance (based on a predetermined index) has been compared with several conventional methods to show the performance improvement of multi-input stochastic systems through the proposed sliding surface.
