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A fractional adaptation law for sliding mode control
Author(s) -
Efe Mehmet Önder,
Kasnakog̃lu Cosku
Publication year - 2008
Publication title -
international journal of adaptive control and signal processing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 66
eISSN - 1099-1115
pISSN - 0890-6327
DOI - 10.1002/acs.1062
Subject(s) - control theory (sociology) , robustness (evolution) , initialization , nonlinear system , sliding mode control , fractional calculus , controller (irrigation) , computer science , adaptive control , law , engineering , mathematics , control engineering , control (management) , artificial intelligence , physics , biochemistry , chemistry , quantum mechanics , biology , agronomy , gene , programming language , political science
This paper presents a novel parameter tuning law that forces the emergence of a sliding motion in the behavior of a multi‐input multi‐output nonlinear dynamic system. Adaptive linear elements are used as controllers. Standard approach to parameter adjustment employs integer order derivative or integration operators. In this paper, the use of fractional differentiation or integration operators for the performance improvement of adaptive sliding mode control systems is presented. Hitting in finite time is proved and the associated conditions with numerical justifications are given. The proposed technique has been assessed through a set of simulations considering the dynamic model of a two degrees of freedom direct drive robot. It is seen that the control system with the proposed adaptation scheme provides (i) better tracking performance, (ii) suppression of undesired drifts in parameter evolution, (iii) a very high degree of robustness and improved insensitivity to disturbances and (iv) removal of the controller initialization problem. Copyright © 2008 John Wiley & Sons, Ltd.