This article investigates the problem of simultaneous attitude and vibration CONTROL of a flexible spacecraft to perform high precision attitude maneuvers and reduce vibrations caused by the flexible panel excitations in the presence of external disturbances, SYSTEM uncertainties, and actuator faults. Adaptive integral sliding mode CONTROL is used in conjunction with an attitude actuator fault iterative learning observer (based on sliding mode) to develop an ACTIVE fault tolerant algorithm considering rigid-flexible body dynamic interactions. The discontinuous structure of fault-tolerant CONTROL led to discontinuous commands in the CONTROL signal, resulting in chattering. This issue was resolved by introducing an adaptive rule for the sliding surface. Furthermore, the utilization of the sign function in the iterative learning observer for estimating actuator faults has not only enhanced its robustness to external disturbances through a straightforward design, but has also led to a decrease in computing workload. The strain rate FEEDBACK CONTROL algorithm has been employed with the use of piezoelectric sensor/actuator patches to minimize residual vibrations caused by rigid-flexible body dynamic interactions and the effect of attitude actuator faults. Lyapunov's law ensures finite-time overall SYSTEM stability even with fully coupled rigid-flexible nonlinear dynamics. Numerical simulations demonstrate the performance and advantages of the proposed SYSTEM compared to other conventional approaches.

In this paper, the chaotic dynamic analysis along with chaos CONTROLler of an ACTIVE suspension in vehicle has been studied. The unstable periodic orbits of the SYSTEM are stabilized using the developed delay FEEDBACK CONTROL algorithm based on the fuzzy sliding mode SYSTEM. Firstly, the equations of model are derived via Newton-Euler rules and then, power spectrum density and bifurcation diagrams have been used to confirm chaos in the SYSTEM. Variations of the CONTROL parameters in the bifurcation diagrams demonstrate the changes of SYSTEM behavior from the periodic to the irregular chaotic responses. Finally, to eliminate the chaos in the vertical dynamics of vehicle, a novel fuzzy sliding delay FEEDBACK CONTROL algorithm is developed on the ACTIVE suspension. Using fuzzy logic, the CONTROLler gain of the sliding delay FEEDBACK CONTROL is online estimated that is caused to reject the chattering phenomenon in the sliding mode algorithm beside the improvement of the responses. Simulation results of the CONTROL SYSTEM depict a reduction of settling time and energy consumption along with eliminating the overshoots and chaotic vibrations.

Reaction wheels (RWs) used for attitude CONTROL of space vehicle SYSTEMs usually encounter with undesired wide band NOISEs. These NOISEs which significantly affect the performance of regulator CONTROLler must tune the review or review rate of RWs. According to wide frequency band of NOISEs in RWs the common approaches of NOISE cancellation cannot conveniently reduce the effects of the NOISE. Therefore, the advanced analyzer of frequency domain signal processing such as wavelets must be used to realize the NOISE cancellation. In this regards, only the online application of wavelets can be practical. In this paper, an online ACTIVE NOISE canceller based on online wavelet theory is employed to omit the effects of undesired NOISE. In this way, dynamic identification of a RW as well as wavelet delay compensation are used simultaneously to design an ACTIVE NOISE cancellation SYSTEM. Numerical and experimental investigations of KNTU test setup as a hard ware in the loop SYSTEM show the preferences of the proposed method of online NOISE cancellation.

A common method for CONTROLling a group of parallel converters in decentralized CONTROL strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this method is that the reACTIVE power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from dynamic stability problems such as power fluctuations, which can be increased by switching between ACTIVE and reACTIVE power CONTROL. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient CONTROLlers. By linearizing and simplifying conditions, the CONTROL SYSTEM conversion function model becomes a single input-single output SYSTEM, which is efficient enough to show the relationship between CONTROL parameters such as slope of droop characteristics and derivative sentences, virtual impedance, and voltage CONTROLlers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between ACTIVE and reACTIVE power CONTROL and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.

Non-cooperative intelligent CONTROL agents (ICAs) with dedicated cost functions, can lead the SYSTEM to poor performance and in some cases, closed-loop instability. A robust solution to this challenge is to place the ICAs at the FEEDBACK Nash equilibrium point (FNEP) of the differential game between them. This paper introduces the designation of a robust decentralized infinite horizon LQR CONTROL SYSTEM based on the FNEP for a linear time-invariant SYSTEM. For this purpose, two CONTROL strategies are defined. The first one is a centralized infinite horizon LQR (CIHLQR) problem (i.e. a supervisory problem), and the second one is a decentralized CONTROL problem (i.e. an infinite horizon linear-quadratic differential game). Then, while examining the optimal solution of each of the above strategies on the performance of the other, the necessary and sufficient conditions for the equivalence of the two problems are presented. In the absence of the conditions, by using the least-squares error criterion, an approximated CIHLQR CONTROLler is presented. It is shown that the theorems could be extended from a two-agent CONTROL SYSTEM to a multi-agent SYSTEM. Finally, the results are evaluated using the simulation results of a Two-Area non-reheat power SYSTEM.

ACTIVE CONTROL of sinusoidal acoustic NOISE in an experimental phone kiosk is investigated. This is performed by implementation of a single-channel and a 1x2x2 multiple channel FXLMS ACTIVE NOISE CONTROL (ANC) SYSTEM in a 1X 1X2 m phone kiosk. The secondary path transfer functions are identified using an offline technique. The results show that both ANC SYSTEMs generate a quiet zone with 15 dB NOISE attenuation in each error microphone. In this way, using the multiple-channel one, two quiet zones are produced at two locations in the kiosk. Further experiments also revealed that the multiple-channel SYSTEM is stable for a wider range of NOISE frequencies, and therefore, more appropriate for multi-tonal NOISE cancellation.