Search

In this paper, an adaptive fuzzy tracking control is presented for a class of SISO nonlinear strict feedback systems with unknown time delays. The proposed algorithm does not use the backstepping scheme rather it converts the strict-feedback time-delayed system to the normal form. The Mamdani-type fuzzy system is employed to approximate on-line the lumped uncertain system nonlinearity. The developed controller guarantees uniform ultimate boundedness of all signals in the closed-loop system. The designed control law is independent of the time delays and has a simple form with only one adaptive parameter vector needed to be updated on-line. As a result, the proposed control algorithm is considerably simpler than the previous ones based on backstepping. The Lyapunov stability of the fuzzy system parameters and the filtered tracking error is employed to guarantee semiglobal uniform boundedness for the closed loop system. Simulation results are presented to verify the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Time delay introduced by sampling and calculation exists between the perturbation and the duty ratio updating in the digital control loop. This time delay degrades the transient performance of digital control switching power supplies. By overcoming the sampling and calculation time effect and to calibrate the ripple that occurs during switching cycles, new control algorithm is proposed in this paper to improve the transient performance of switching power supplies by eliminating the time delay in the control loop. Simulation results show the improvement of load transient performance by the proposed algorithms. Experimental system is also set up to verify the analysis and computer simulation results. [ABSTRACT FROM AUTHOR]