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Civil-Comp Proceedings
ISSN 1759-3433
CCP: 77
PROCEEDINGS OF THE NINTH INTERNATIONAL CONFERENCE ON CIVIL AND STRUCTURAL ENGINEERING COMPUTING
Edited by: B.H.V. Topping
Paper 115

Continuous Bounded Controller for Active Control of Structures

Y. Arfiadi+ and M.N.S. Hadi*

+Department of Civil Engineering, Faculty of Engineering, Atma Jaya Yogyakarta University, Yogyakarta, Indonesia
*Faculty of Engineering, University of Wollongong, Australia

Full Bibliographic Reference for this paper
Y. Arfiadi, M.N.S. Hadi, "Continuous Bounded Controller for Active Control of Structures", in B.H.V. Topping, (Editor), "Proceedings of the Ninth International Conference on Civil and Structural Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 115, 2003. doi:10.4203/ccp.77.115
Keywords: active control structures, continuous control, bounded control, response reduction, modified bang-bang controller, chattering effect.

Summary
This paper considers nonlinear controllers for controlling buildings subject to earthquake excitations. The controller utilises continuous function to approximate the bang-bang type controller. It is to be noted that although much progress has been achieved in structural control of civil engineering structures [1,2,3,4,5], most algorithms are linear control with the assumption that there is no limit in magnitude of the control energy. However, maximum capacity of the control device is limited. Therefore, designing controllers that include the bounded nature of the device is desirable. Only a few researchers consider bounded controller for active control of civil engineering structures [6,7,8,9,10]. In this paper modified bang-bang controllers considered in [8,10] is approximated by using a continuous function [11]. A hyperbolic function is used in this present application. Such controllers are capable of alleviating high-speed switching effect that are present in the traditional bang-bang controllers.

Numerical simulations to active control systems under several input disturbances from various earthquakes are then presented by using MATLAB [12] and SIMULINK [13]. Numerical simulations show the potential benefit of using the proposed controller to reduce the structural response subject to earthquake excitations.

Numerical comparison with the bang-bang type controller shows that the effectiveness of the proposed controller is almost the same. However, the high-speed switching command that usually occurs in the bang-bang type controller might be avoided.

Numerical simulation under particular earthquake acceleration, but different level of the actuator capacity, shows that the controller tends to utilise the maximum capacity of the actuator when the maximum capacity of the actuator is reduced. Thence, it resembles the bang-bang controller. However, by adjusting the weighting variable in the controller, the high-speed switching control command might be alleviated.

References
1
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N. Mostaghel and T. Davis, "Representations of Coulomb friction for dynamic analysis", Earthquake Engineering and Structural Dynamics, 26, 541-548, 1997. doi:10.1002/(SICI)1096-9845(199705)26:5<541::AID-EQE660>3.3.CO;2-N
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I.E. Kose, W.E. Schmitendorf, F. Jabbari, J. N. Yang, "H_infinity seismic response control using static output feedback", Journal of Engineering Mechanics, 22(7), 651-659, 1996. doi:10.1061/(ASCE)0733-9399(1996)122:7(651)
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"Using SIMULINK", The Math Works, Inc., Natick, MA, 1996.

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