This paper presents fractional order fixed-time nonsingular terminal sliding mode control for stabilization and synchronization of fractional order chaotic systems with uncertainties and disturbances. First, a novel fractional order terminal sliding mode surface is proposed to guarantee the fixed-time convergence of system states along the sliding surface. Second, a nonsingular terminal sliding mode controller is designed to force the system states to reach the sliding surface within fixed-time and remain on it forever. Furthermore, the fractional Lyapunov stability theory is used to prove the fixed-time stability and the robustness of the proposed control scheme and estimate the upper bound of convergence time. Next, the proposed control scheme is applied to the synchronization of two nonidentical fractional order Liu chaotic systems and chaos suppression of fractional order power system. Simulation results verify the effectiveness of the proposed control scheme. Finally, some application issues about the proposed scheme are discussed.
相似文献This paper introduces a homogeneous controller along a fixed-time state and fault observer for finite-time stabilization and fault accommodation of a remotely-operated vehicle in the presence of actuator saturation and rate limits. For this, a novel tuning algorithm is improvised for manipulating the degree of homogeneity in homogeneous controllers to effectively acquire different properties from the overall control system. The tuning of degree of homogeneity is based on vehicle’s velocity. The proposed algorithm results in a switching-type controller, which undergoes three different stages during the operation, to eliminate the sensitivity of conventional finite-time and fixed-time controllers to large initial errors in the presence of thruster constraints. In addition, a new fixed-time fault and state observer is designed for the realization of output feedback control and fault tolerance by combining a fixed-time state observer with a fault estimation unit. In contrast to conventional extended-state observers, this observer considers the dynamics of the thruster system in its formulation so that better performance can be provided for the control system upon thruster failures. Control allocation is utilized to accommodate thruster failures and faults and to take account of thruster saturation and rate limits. Stability analyses are carried out for the overall control system and the proposed observer. It is shown that the closed-loop control system would be globally finite-time stable. The state estimation subsystem is fixed-time stable and the fault estimation unit is input-to-state stable. Simulations are carried out and comparisons are made with several finite-time and fixed-time controllers to outline the advantages of the proposed homogeneous controller and the benefits of the overall fault-tolerant control system.
相似文献This paper studies an approximate continuous fixed-time terminal sliding mode control (CFTSMC) with prescribed performance for uncertain robotic manipulators. A transformation concerning tracking error using a fixed-time prescribed performance function is proposed to guarantee the transient and steady-state performance of trajectory tracking control for uncertain robotic manipulators within fixed time. Utilizing the transformed error, a smooth fixed-time sliding mode surface is designed. Then, based on the proposed sliding mode surface, an approximate CFTSMC scheme is presented to achieve inherent chattering-free control for uncertain robotic manipulators. According to the Lyapunov stability theory, it is proved that the position tracking error can be bounded in the prescribed performance boundaries and globally converges to a defined small region within fixed time and then approaches exponentially to the origin. Several numerical simulation results demonstrate the effectiveness and superiority of the proposed control strategy for uncertain robotic manipulators.
相似文献The fixed-time stabilization problem is addressed in this paper for a kind of nonholonomic systems in chained form with unmatched uncertainties and time-varying output constraints. A novel tan-type barrier Lyapunov function is introduced to deal with time-varying output constraints. Under the unified framework of the considered system with and without output constraints, a state feedback controller is designed with the aid of adding a power integrator technique and switching control strategy. It is shown that the suggested controller ensures the states of closed-loop system to zero in a given fixed time without disobeying the constraints. Finally, simulation results are given to confirm the efficacy of the presented control scheme.
相似文献In the present article, a terminal sliding mode control strategy has been proposed in order to address the synchronization problem for a class of perturbed nonlinear systems with fixed convergence time and input quantization. The proposed protocol guarantees the fixed-time convergence of the sliding manifold to the origin, which means that the convergence time of the proposed sliding manifold does not change on the variations of initial values, different from typical control methods. Here, the hysteresis quantizer, as a specific type of quantizer with nonlinear sector-bounded, is applied in order to quantize the input signal. The proposed quantized control scheme vigorously prevents the potential adverse chattering phenomenon which is experienced in the common quantization methods. The proposed controller does not need the limiting criteria related to considered parameters of quantization compared to recent control approaches. Finally, the designed controller is implemented on the perturbed Genesio–Tesi (G–T) chaotic systems to verify effectiveness and strength of the proposed method.
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