• Journal of IKEEE
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• v.9 no.2 s.17
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• pp.87-100
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• 2005

In this paper, a design of an integral augmented optimal variable structure system(IOVSS) is presented for the prescribed output control of uncertain SISO systems under persistent disturbances. This algorithm aims at removing the problems of the reaching phase by incorporating advanced optimal control theory. By means of an integral sliding surface, the reaching phase is completely removed, and the integral sliding surface can be defined from a given initial state to origin without any reaching phase. The ideal sliding dynamics of the integral sliding surface is obtained in the form of the state equation and is designed in an optimal sense by targeting the design of the integral sliding surface and equivalent control input. The corresponding control input is selected in order to generate the sliding mode on the predetermined integral sliding surface. As a result, the whole sliding output from a given initial state to origin is completely guaranteed against persistent disturbances. Moreover the prediction/predetermination of output is enabled, which helps in improving the performance over previously implemented VSS's. Through an illustrative example, the usefulness of the algorithm is shown.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.2
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• pp.124-131
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• 2002

This paper presents the design of an active vibration suppression controller for an air-spring type vibration isolation table. Firstly, isolation system model is constructed considering the isolation table, attached equipment and voice-coil actuator. An active control system is designed based on frequency-shaped sliding mode control theory rewarding high frequency uncertainties with respect to attached equipments on the isolation table. Finally. the performance of the active isolation system is evaluated by simulation under some disturbance conditions which are transmitted from base structure of the isolation system.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.9
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• pp.788-792
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• 2001

Although the general sliding model control has the robust property, bounds on the disturbances and parameter variations should be known a prior to the designer of the control system. However, these bounds may not be easily obtained. Fuzzy logic provides an effective way to design a controller of the system with disturbances and parameter variations. Therefore, combination of the best feature of the fuzzy logic control and the sliding mode control is considered. In this paper, the adaptive fuzzy variable structure controller developed for variables of fuzzy logic. A variable length pendulum system is used to demonstrate the availability of the proposed algorithm.