共查询到20条相似文献，搜索用时 15 毫秒
1.
This paper presents an adaptive iterative learning control (AILC) scheme for a class of nonlinear systems with unknown time-varying delays and unknown input dead-zone. A novel nonlinear form of dead-zone nonlinearity is presented. The assumption of identical initial condition for iterative learning control (ILC) is removed by introducing boundary layer function. The uncertainties with time-varying delays are compensated for by using appropriate Lyapunov-Krasovskii functional and Young0s inequality. Radial basis function neural networks are used to model the time-varying uncertainties. The hyperbolic tangent function is employed to avoid the problem of singularity. According to the property of hyperbolic tangent function, the system output is proved to converge to a small neighborhood of the desired trajectory by constructing Lyapunov-like composite energy function (CEF) in two cases, while keeping all the closedloop signals bounded. Finally, a simulation example is presented to verify the effectiveness of the proposed approach. 相似文献
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This paper addresses the problem of finite-time stabilisation by state feedback for a class of stochastic nonlinear systems in strict-feedback form. Remarkably, the system under consideration possesses high-order and low-order nonlinear growth rates and the dead-zone input. By delicately combining sign function with adding a power integrator technique, a state feedback controller is designed such that the closed-loop system is finite-time stable in probability. Simulation results of the parallel active suspension system are provided to show the effectiveness of the proposed method. 相似文献
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In this article, under the circumstance of dead zones input and unknown control direction, the adaptive practical fixed-time control strategy is presented for a general class of multi-input and multi-output (MIMO) nonlinear systems. The inherent explosion of computational complexity difficulty is eliminated by adopting a command filter technique and the universal approximation properties of radial basis function neural networks (RBFNNs) are applied to model the unknown nonlinear functions. The difficulties of the dynamic surface method and unknown directions can be handled by invoking error compensation mechanism and Nussbaum-type functions, respectively. The uniqueness of the presented control scheme is that the tracking system can achieve the fixed-time stability without relying on the boundedness of dead-zone parameters. The fixed-time convergence of the output tracking error and the semiglobally fixed-time stable of closed-loop system are assured via the developed adaptive fixed-time command filtered controller. Finally, a practical example is supplied to further validate the availability of the presented theoretic result. 相似文献
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针对具有传感器故障的一类严格反馈非线性系统, 提出一种有限时间自适应动态面容错控制策略. 考虑的传感器故障包括: 固定偏差故障、漂移故障、精度下降及失效故障. 以反步法为主要设计依据, 利用模糊逻辑系统处理模型中的未知函数. 该控制策略的显著优势在于结合有限时间理论、容错控制、模糊逻辑控制及动态面控制, 使得系统无论发生故障与否, 均使得系统在原点处是半全局实际有限时间稳定, 同时保证系统的实际输出信号在有限时间内跟踪期望信号, 且跟踪误差收敛于坐标原点的小邻域内. 另外, 通过采用动态面控制技术克服了传统反步法中的计算复杂问题. 最后, 仿真算例证明了该设计方案的有效性. 相似文献
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研究一类具有外部扰动的非线性系统在初始跟踪条件未知情况下的预设性能有限时间有界$H_infty$控制问题.针对预设性能控制设计,提出一个新的误差转换思想,并据此设计新的预设性能函数,解决预设性能控制依赖于系统被约束量初始条件的问题.基于所提出预设性能函数、有限时间控制理论以及有界$H_infty$的设计方法,获得系统无需初始跟踪条件的预设性能有限时间有界$H_infty$控制器,同时解决非线性系统在有界稳定情况下难以设计$H_infty$控制器的问题,保证跟踪误差以预先设定的动态性能在有限时间内收敛至平衡点附近的小邻域内,并对外部干扰有较强的鲁棒性能. 相似文献
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The finite time adaptive filter control problem is studied for strict-feedback nonlinear systems with actuator faults and state constraints in this paper. First, with the aid of the backstepping technique, the controller and the adaptive laws are designed to compensate the actuator faults and parameter uncertainties. Then, the dynamic surface control is used to establish a first-order filter to alleviate computational burden for the reason of the derivative of virtual control laws. In addition, none of the system states violate predefined constraint boundaries by utilizing a log-type barrier Lyapunov function. Furthermore, the boundedness can be ensured for all the closed-loop signals, and better tracking performance of the system is obtained within a finite-time. Finally, the simulation examples are shown to prove the feasibility and effectiveness of the proposed strategy. 相似文献
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在实际工业系统中普遍存在输入死区、全状态约束等不可忽视的问题,其对系统的性能造成较大的影响,甚至可能会导致系统不稳定.为了克服上述问题,针对一类不确定非线性系统,提出一种快速收敛的自适应神经网络事件触发控制方法.首先,将障碍Lyapunov函数引入到反步控制框架中,采用径向基函数神经网络逼近未知非线性函数,同时设计自适应事件触发机制对输入死区进行动态补偿,通过减少控制信号的更新频率来减轻系统的通信负担,并保证系统所有状态不违反预定义的约束区间.在此基础上,引入快速有限时间稳定理论,在有限时间内能够保证闭环系统所有信号的有界性以及跟踪误差快速收敛到有界的紧集内.最后,通过两个仿真算例验证所提出控制方法的有效性. 相似文献
10.
Changchun Hua;Wenlong Pan; 《国际强度与非线性控制杂志
》2024,34(9):5873-5888
》2024,34(9):5873-5888
In this article, a class of global finite-time stabilization problem for high-order stochastic nonlinear systems with multiple unknown control directions is studied. In order to solve the difficulties caused by the unknown control directions and at the same time, the system is required to converge to the origin in a limited time. Therefore, a new switching mechanism based on the Lyapunov-like function is proposed. By adding a power integral technique and utilizing sign function, a finite-time switching controller is designed. The controller parameters need to be adjusted online according to the proposed switching logic. It is rigorously proved that the designed controller can make the system state converge probabilistically to the origin in a finite-time. A simulation example shows the effectiveness of the proposed control algorithm. 相似文献
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Yumeng Cao;Ben Niu;Huanqing Wang;Xudong Zhao; 《国际强度与非线性控制杂志
》2024,34(7):4769-4786
》2024,34(7):4769-4786
This paper investigates an event-triggered adaptive resilient control problem for nonlinear systems against unknown false data injection and actuator saturation. The sensors of the controlled system are subject to unknown false data injection attacks so that all original states can not be directly applied in the controller design process. To address the negative effects of the false data injection attacks, attack compensators are introduced in control design. Simultaneously, a dynamic event-triggering mechanism is set up to reduce the communication burden of the network. Furthermore, an auxiliary system is constructed to cope with the actuator saturation that commonly exists in practical systems. Based on the Lyapunov stability theory, it is demonstrated that the designed adaptive controller can guarantee the stability of the controlled system and the boundedness of all signals. The validity of the proposed control scheme is evidenced by simulation examples. 相似文献
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针对一类严格反馈非线性系统,提出一种基于有限时间指令滤波的自适应固定时间预设性能控制策略.首先,引用非线性映射技术及适当的误差变换,建立等效的误差模型;其次,综合利用反步法、固定时间控制和自适应控制等方法,设计一种基于有限时间指令滤波的预设性能跟踪控制器.该策略应用指令滤波器解决了反步法中对虚拟控制律反复求导问题,减轻了计算负担.此外,预设性能控制和固定时间控制保证了系统的跟踪误差能够在固定时间内收敛到预设性能函数限定的范围内,其收敛时间与系统初始条件无关,且确保系统中全部信号在有限时间均达到有界区域.理论分析与仿真验证均表明了所提出设计方法的有效性. 相似文献
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In this paper, we propose a new universal output feedback adaptive controller to globally (or semiglobally) stabilize nonlinear output feedback systems, whose nonlinearities are bounded either by known functions with unknown parameters or by completely unknown functions. In addition, no a priori knowledge of the sign of high‐frequency gain is required. The new design focuses on properly arranging the control gains step by step in the filter backstepping design. Instead of Lyapunov‐based argument, an inductive contradiction argument is employed in the proof of stability, which is not common in literature. 相似文献
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This paper is concerned with the event‐triggered control problem for a class of strict feedback nonlinear networked systems. Different from the existing design methods, a novel user‐adjustable event‐triggered mechanism is first developed to determine the sampling state instants using the negative definite property of the derivatives of Lyapunov functions. Then, an event‐triggered control strategy is devised based on the sampled state vectors and backstepping techniques. It is proved that the proposed control scheme ensures the global convergence of the closed‐loop systems via Lyapunov analyses and the correlation criteria of real variable functions. Finally, two examples are performed to illustrate the effectiveness of the provided control approaches. 相似文献
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针对一类严格反馈非线性系统,利用后推法设计一种无超调跟踪控制律.对于阶数小于4的对象,给出了控制律参数应满足的充要条件;对于阶数更高的对象,给出了求解一个充分条件的方法.该控制律适用于零与非零初始条件,且参考输出不限制为阶跃信号.通过两个数值仿真例子验证了所提出控制律的有效性. 相似文献
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This paper addresses the global stabilization via adaptive output‐feedback for a class of uncertain nonlinear systems. Remarkably, the systems under investigation are with multiple uncertainties: unknown control directions, unknown growth rates and unknown input bias, and can be used to describe more physical plants. Multiple uncertainties, which usually cannot be compensated by a sole compensation technique, may give rise to big technical difficulty for controller design. To overcome such difficulty and to achieve the global stabilization, a new adaptive output‐feedback scheme is proposed in this paper, by flexibly combining Nussbaum‐type function, tuning function technique and extended state observer. It is shown that, under the designed controller, the system states globally converge to zero. A simulation example on non‐zero set‐point regulation is given to demonstrate the effectiveness of the theoretical results. 相似文献
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This paper investigates the output feedback control for the uncertain nonlinear system with the integral input‐to‐state stable (iISS) cascade subsystem, which allow not only the unknown control direction but also the unknown output function. The unknown output function only needs to have a generalized derivative (which may not be derivable), and the upper and lower bounds of the generalized derivative need not to be known. To deal with the challenge raised by the unknown output function and the unknown control direction, we choose a special Nussbaum function with a faster growth rate to ensure the integrability for the derivative of the selected Lyapunov function. Then, a dynamic output feedback controller is designed to drive the system states to the origin while keeping the boundedness for all other closed‐loop signals. Moreover, via some appropriate transformations, the proposed control scheme is extended to deal with more general uncertain nonlinear cascade systems with quantized input signals. Finally, two simulation examples are given to show the effectiveness of the control scheme. 相似文献
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Guo Yu;Wenhui Liu; 《国际强度与非线性控制杂志
》2024,34(14):9654-9675
》2024,34(14):9654-9675
This article proposes a tracking control strategy based on fixed-time for uncertain nonlinear systems with prescribed performance and actuator faults. Fuzzy logic systems are used to model unknown functions with uncertainties or fuzzy parameter features. The improvement of the conventional backstepping method through the introduction of command filtering technology has effectively addressed the challenge of a sharp increase in computational complexity during controller design. Additionally, a mechanism for error compensation has been established to mitigate the potential impact of errors that may arise during the filtering process on the system. Then, a new fixed-time performance function is introduced into the adaptive backstepping method to ensure that the tracking signal with output error converges to an arbitrarily small neighborhood within a fixed time. Additionally, in order to enhance the tracking performance of the control method, the controller algorithm incorporates fault-tolerant control based on the fixed-time performance function. Finally, a numerical simulation of a power system with a static reactive power compensation device is presented, and demonstrate the effectiveness and feasibility of the proposed control algorithm. 相似文献
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Yu-Qun Han;Jing-Jing Sun; 《国际强度与非线性控制杂志
》2024,34(8):5329-5345
》2024,34(8):5329-5345
This article proposes a novel multidimensional Taylor network (MTN)-based adaptive finite-time control approach for stochastic nonlinear systems with input saturation constraints. First, by introducing the hyperbolic tangent function, a piecewise smooth function is proposed to approximate the input saturation constraints, which can solve the problem caused by input saturation. Then, with the aid of MTN approximation theorem, a novel adaptive finite-time control approach is proposed, which can guarantee that all signals of the closed-loop system are semi-globally finite-time stability in probability (SGFTSP), the system output follows the given reference signal, meanwhile, the tracking error converges to a small neighborhood of the origin in finite-time. Compared with the existing results, the proposed approach has the characteristics of simple structure and low calculation, which can achieve the satisfactory control performance with a reduced computational burden. In the end, the effectiveness of the proposed approach is validated by Lyapunov stability theory and two simulation experiments. 相似文献