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.

A novel nonlinear CONTROLler is proposed to track active and reactive power for a Brushless Doubly-Fed Induction Generator (BDFIG) wind turbine. Due to nonlinear dynamics and the presence of parametric uncertainties and perturbations in this system, SLIDING MODE CONTROL is employed. To generate a smooth CONTROL signal, dynamic SLIDING MODE method is used. Uncertainties bound is not required in the suggested algorithm, since the ADAPTIVE gain in the CONTROLler relation is used in this study. Convergence of the SLIDING variable to zero and ADAPTIVE gain to the uncertainty bound are verified using Lyapunov stability theorem. The proposed CONTROLler is evaluated in a comprehensive simulation on the BDFIG MODEl. Moreover, output performance of the proposed CONTROL algorithm is compared to the conventional and second-order SLIDING MODE and proportional-integral-derivative (PID) CONTROLlers.

Two phenomena can produce chattering: switching of input CONTROL signal and the large amplitude of this switching (switching gain). To remove the switching of input CONTROL signal, dynamic SLIDING MODE CONTROL (DSMC) is used. In DSMC switching is removed due to the integrator which is placed before the plant. However, in DSMC the augmented system (system plus the integrator) is one dimension bigger than the actual system and then, the plant MODEl should be completely known. To overcome this difficulty, a fuzzy system is employed to identify the unknown nonlinear function of the plant MODEl and then, a robust ADAPTIVE law is developed to train the parameters of this fuzzy system. The other problem is that the switching gain may be chosen unnecessary large to cope on the unknown uncertainty. To solve this problem, another fuzzy system is proposed which does not need the upper bound of the uncertainty. Moreover, to have a suitable small enough switching gain an ADAPTIVE procedure is applied to increase and decrease the switching gain according to the system circumstances. Then, chattering is removed using the DSMC with a small ADAPTIVE switching gain (ASG). As a case study, nonlinear chaotic Duffing-Holmes system is selected.

This paper deals with a globally convergent ADAPTIVE and SLIDING MODE CONTROL of a cart-pole inverted pendulum for trajectory tracking in the presence of a bounded measurement noise and parameter uncertainty. Two kinds of CONTROLlers have been used for evaluation of tracking error in presence of a bounded noise; as a result, we want to compare that at what time we can see the convergence of tracking error and which CONTROLler can perform better? Simulation results on a cart-pole inverted pendulum are shown for trajectory tracking in presence of impulse disturbance.

According to the critical role of gas turbines in the industry, monitoring the performance of gas turbines is an important issue since it can prevent unexpected shutdowns and the serious consequent financial harms. One of the most important parts of a gas turbine is the combustion chamber. Although the internal pressure and temperature of the combustion chamber can directly affect the performance and useful life of this part, however, it is not possible to measure it directly through sensors. Therefore, estimation of pressure variable is a good choice to achieve greater performance and more relative stability comparing with the methods in which there is no access to the internal pressure of the chamber. In this research, a suitable nonlinear dynamic MODEl with produced power and exhausted gas temperature as its outputs is chosen. Thereafter, an ADAPTIVE surface SLIDING observer is designed in order to estimate the combustion pressure and temperature, which are the state variables of the gas turbine. Afterward, utilizing a SLIDING MODE CONTROLler and applying the estimated states, the produced power and exhaustion gas temperature of the gas turbine would be CONTROLled. In this paper, the stability of the closed-loop system in the presence of the state observer through the Lyapunov approach is guaranteed. Finally, simulation results are provided to verify the validity and efficiency of the proposed method.

In this paper, a new ADAPTIVE fractional-order SLIDING MODE CONTROLler is designed for a Permanent Magnet Synchronous Generator (PMSG) to track the maximum power point. The CONTROLler objective is to track the desired generator speed to extract the maximum power from the wind turbine system in the presence of parametric uncertainty and external disturbances. First, a new fractional order SLIDING surface is defined. To ensure the stability of the closed-loop system in the SLIDING MODEl CONTROLler it is required to know the upper bounds of uncertainties and disturbances, where it is difficult to calculate these bounds for practical applications such as wind turbines. Therefore, the CONTROL signal parameters are estimated online by the proposed ADAPTIVE laws, in order to increase the convergence rate of the state variables to the reference value and reduce the chatting phenomenon, also to increase the system robustness against external disturbances and parametric uncertanity. On the other hand, due to the unknown disturbance dynamics, a disturbance observer is designed to estimate external disturbances and parametric uncertainty. Then, the stability of the general closed-loop system together with the disturbance observer is performed using Lyapunov's theory. Finally, the simulation results considering two different scenarios; first for step wind changes with external disturbance, second for changes in sine wind speed with parametric uncertainty. The results are compared with conventional SLIDING MODE CONTROLler and results show the effective performance of the proposed CONTROLler in tracking the reference value, increasing its robustness against uncertainty and disturbance and reducing the chatting phenomenon.

This paper proposes an ADAPTIVE SLIDING MODE CONTROL scheme for steer-by-wire (SBW) vehicles subject to tire burst in the presence of uncertainties and external disturbances. To estimate the lateral slip angle of the vehicle after the tire has burst, a SLIDING MODE observer is provided to estimate the lateral slip angle through rotational speed and lateral acceleration measurements. First, an ADAPTIVE SLIDING MODE CONTROLler ((ASMC)), as a high-level lateral stability CONTROLler, is designed to calculate the modified steering angle and achieve the desired rotational speed and slip angle. In addition, an ADAPTIVE rule is included in the CONTROL rule to estimate the switching gain so as to overcome the lack of information due to complex uncertainty. The desired steering angle is then created by a lower steering CONTROLler via an ADAPTIVE SLIDING MODE CONTROLler for an SBW wired steering system. The simulation results in MATLAB Simulink and CarSim software show the optimal stability CONTROL for different steering maneuvers by bursting the tire. Finally, the comprehensive performance of the ADAPTIVE slip MODE CONTROLler design in tracking the main track and CONTROLling lateral stability is evaluated and discussed.