Adjustable prescribed performance fixed time control for saturated nonlinear systems

DOI:	10.11809/bqzbgcxb2024.12.034
Keywords:	prescribed performance control; fixed time control; auxiliary system; fuzzy logic system; dynamic surface control
Abstract:	An adjustable prescribed performance fixed time control method is proposed for a class of nonlinear strict feedback system with actuator saturation. In order to effectively reconcile the contradiction between the system input constraints and performance constraints, a new fixed time auxiliary system is designed, and the non negative auxiliary system state is introduced into a finite time small overshoot prescribed performance function to obtain a new type of autonomously adjustable prescribed performance function. In order to avoid the differential explosion phenomenon and singularity problem in the system design process, the fixed time controllers and dynamic surface filters without fractional power terms are devised. Aiming at the unknown nonlinear function in the system, the fuzzy logic system is utilized for approximation. At the same time, in order to reduce the computation amount of online parameter updating, the fuzzy parameters are updated by using the minimum parameter learning method.Both theoretical analysis and simulation results demonstrate that the proposed control method can ensure that the system does not violate the performance constraints when actuator saturation occurs, and that all signals of the closed loop system are uniformly ultimately bounded within a fixed time.
Issue:	Vol. 45 No. 12 (2024)
Published:	2024-12-30
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