首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
    
This article investigates an adaptive fuzzy tracking control problem for a class of nontriangular form systems with asymmetric time-varying full state constraints. Unknown functions are approximated by the fuzzy logic systems. A domination approach is employed to tackle the nontriangular form structure. Time-varying asymmetric barrier Lyapunov functions (ABLFs) are adopted to ensure full-state constraints satisfaction. Based on the backstepping technique and time-varying ABLFs, an adaptive controller is proposed and guarantees that all the signals in the closed-loop system are ultimately bounded and the time-varying full state constraints are met. Simulation examples are presented to further demonstrate the effectiveness of the proposed approach.  相似文献   

2.
    
  相似文献   

3.
研究了一类具有饱和执行器且含不匹配不确定性和匹配外界扰动的变时滞系统的稳定性问题。基于滑模控制原理提出了一种自适应控制方法。该方法不仅取消了饱和界已知的条件,而且给出了滑动模态存在性和可达性的条件。  相似文献   

4.
    
In this paper, a finite-time optimal control (FTOC) strategy is proposed for output constrained uncertain nonlinear systems with input saturation. The controller adopts a feed-forward and optimal feedback control structure. The second-order command filter and the auxiliary error compensation system are designed in the feed-forward controller, which can eliminate the influence of filtering error on system performance while avoiding the singularity problem of finite-time control. A new critic weight updating law is proposed in the design of the optimal feedback controller, in which a neural network is utilized to approximate the relevant cost function. The control scheme can ensure that all signals in the optimize system are semi-global practical finite-time stable (SGPFS), and the cost function is also minimized. The effectiveness of the algorithm is validated through simulation examples.  相似文献   

5.
    
This article concentrates on an adaptive finite-time fault-tolerant fuzzy tracking control problem for nonstrict feedback nonlinear systems with input quantization and full-state constraints. By utilizing the fuzzy logic systems and less adjustable parameters method, the unknown nonlinear functions are addressed in each step process. In addition, a dynamic surface control technique combined with fuzzy control is introduced to tackle the variable separation problem. The problem for the effect of quantization and unlimited number of actuator faults is tackled by a damping term with smooth function in the intermediate control law. Finite-time stability is achieved by combining barrier Lyapunov functions and backstepping method. The finite-time controller is designed such that all the responses of the systems are semiglobal practical finite-time stable and ensured to remain in the predefined compact sets while tracking error converges to a small neighborhood of the origin in finite time. Finally, simulation examples are utilized to testify the validity of the investigated strategy.  相似文献   

6.
    
The adaptive control for a class of high-order nonlinear systems with time-varying full-state constraints and input saturation is investigated in this paper. To deal with time-varying constraints, a type of high-order barrier Lyapunov functions(BLFs) are constructed. Its performance can be guaranteed with the disappearance of constraints. By building fuzzy systems, unknown functions can be approximated. Together with adding a power integrator technique and the gain-update law, an adaptive controller is designed. As a result, all the constraints are not breached, and the tracking error converges to an arbitrarily small zone around the origin. Finally, a practical example and a numerical example illustrate the effectiveness of the proposed method.  相似文献   

7.
    
In this article, the fuzzy adaptive finite-time consensus tracking control problem for nonstrict feedback nonlinear multiagent systems with full-state constraints is studied. The finite-time control based on command filtered backstepping is proposed to guarantee the finite-time convergence and eliminate the explosion of complexity problem caused by backstepping process, and the errors in the filtering process are compensated by using error compensation mechanism. Furthermore, based on the fuzzy logic systems, the uncertain nonlinear dynamics are approximated and the problem of state variables in nonstrict feedback form is solved by using the property of basis functions. The barrier Lyapunov functions are introduced to guarantee that all system states and compensated tracking error signals are constrained in the designed regions. A simulation example is given to verify the superiority of the proposed algorithm.  相似文献   

8.
    
In this presented work, a systematic adaptive stabilization control strategy is proposed for nonholonomic system with parametric uncertainties and full-state constraints. To facilitate the handling of state constraints, the original constrained nonholonomic system is converted into a new unconstrained system by state-dependent function transformations including discontinuous state scalings. The adaptive control algorithm is elaborated by cleverly combing the tuning function design approach with switching control strategy. In stability analysis, it is shown that the designed stabilization control method can realize the desired stabilization control aims and full-state constraints. Simulation is carried out to demonstrate the effectiveness of the control scheme.  相似文献   

9.
    
In this paper, for the nonholonomic tractor-trailer system with slipping and skidding, a full state-triggering implementation of a tracking controller is proposed. Trailers are an important part, and their knowledge is crucial for the safety and control of the vehicle. Without considering system performance constraints, trailers may deviate from their expected position, leading to collisions. Therefore, there is still great interest in addressing the constraint control issues that arise in modern technologies related to network communication. Based on the backstepping method, bounded measurement errors are introduced into the continuous sampling controller considering intra-vehicle communications. Then two neural networks are used to model unknown dynamics of the system with event sampling inputs, thereby decoupling the design of the control inputs. Finally, we prove the input-to-state-like stability of a continuously sampled controller, and the given event execution control law can ensure the boundedness of measurement errors. Simulation results show the effectiveness of the proposed algorithm.  相似文献   

10.
    
In this paper, a novel indirect adaptive fuzzy controller is proposed for a class of uncertain nonlinear systems with input and output constrains. To address output and input constraints, a barrier Lyapunov function and an auxiliary design system are employed, respectively. The proposed approach is explored by employing fuzzy logic systems to tackle unknown nonlinear functions and combining the adaptive backstepping technique with adaptive fuzzy control design. Especially, the number of the online learning parameters are reduced to 2n in the closed‐loop system. It is proved that the proposed control approach can guarantee that all the signals in the closed‐loop system are bounded, and the input and output constraints are circumvented simultaneously. A numerical example with comparisons is provided to illustrate the effectiveness of the proposed approach. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

11.
    
In this work, a fuzzy adaptive two-bits-triggered control is investigated for the nonlinear uncertain systems with input saturation and output constraint. The considered systems are more widespread. Without sufficient transmission resources, how to resolve the constraint issues while guarantee the control performance is difficult and challenging. Then, hyperbolic tangent function and barrier Lyapunov function are integrated with the designed auxiliary system to solve input saturation and output constraint. Meanwhile, faced with the transmission resources limitation, this work both considers the triggering condition and the control signal transmission bits. A two-bits-triggered control is proposed to economize the transmission resources. Furthermore, improved fuzzy logic systems are established to further promote the control performance. It combines with the time-varying approximation error for processing. The boundedness of all the system signals can be proved. Simulation results illustrate the validity of the proposed approach.  相似文献   

12.
    
This article investigated the adaptive backstepping tracking control for a class of pure-feedback systems with input delay and full-state constraints. With the help of mean value theorem, the system is transformed into strict-feedback one. By introducing the Pade approximation method, the effect of input delay was compensated. Radial basis function neural networks are utilized to approximate the unknown nonlinear functions. Furthermore, in order to reduce the computational burden by introducing backstepping design technique, dynamic surface control technique was employed. In addition, the number of the adaptive parameters that should be updated online was also reduced. By utilizing the barrier Lyapunov function, the closed-loop nonlinear system is guaranteed to be semi-globally ultimately uniformly bounded. Finally, a numerical simulation example is given to show the effectiveness of the proposed control strategy.  相似文献   

13.
    
An observer-based adaptive fuzzy backstepping approach is proposed for nonlinear systems with respect to fractional-order differential equations, unmatched uncertainties, unmeasured states, and actuator faults. The approximation capability of fuzzy logic system and minimal learning parameter approaches are applied to identify uncertain functions in a simultaneous manner. For estimating the unavailable conditions, a fuzzy fractional-order state-observer is extended. Applying fault-tolerant approach in a backstepping design methodology would provide a new fault-tolerant adaptive fuzzy output-feedback approach for fractional-order strict-feedback systems. This control structure would assure the considered system stability through selection of the appropriate Lyapunov candidate function. Two numerical simulations are run to exhibit the validity herein.  相似文献   

14.
    
In this article, the optimal tracking control problem is investigated for permanent magnet synchronous motors (PMSMs) with full-state constraints. By constructing multiple barrier-type performance index functions, a neuro-adaptive finite-time optimized control scheme is presented under identifier-actor-critic architecture, where the virtual control laws and the actual laws are designed to optimize corresponding subsystems. It is proven that all signals of the closed-loop system are uniformly ultimately bounded under the proposed control strategy, and the position tracking error converges to a small neighborhood of the origin in finite time. Besides, the system states are constrained to the effective operation range all the time. Finally, the simulation results and comparisons are carried out to further demonstrate the effectiveness of the proposed optimal control approach.  相似文献   

15.
针对铁矿石冶金性能测定过程中的还原气体流量控制系统出现的非线性、时变不确定性问题,在常规PID控制的基础上,结合模糊控制规则,设计了模糊自适应PID控制器,对还原气体流量进行了良好的控制。仿真及实际运行结果表明,该系统鲁棒性强、控制精度高、响应速度快,具有很强的实用价值。  相似文献   

16.
    
This work develops a robust adaptive control algorithm for uncertain nonlinear systems with parametric uncertainties and external disturbances satisfying an extended matching condition. This control method is implemented in the framework of a mapping filtered forwarding‐based technique. As an attractive alternative of the adaptive backstepping method, this bottom‐up strategy forms a virtual controller and a parameter updated law at each step of the design, where Lyapunov functions and the prior knowledge of system parameters are not required. The boundedness of all signals is guaranteed by using Barbalat's lemma. According to immersion relationship, a compliant behavior of systems behaves accordingly to the lower‐order target dynamics. Furthermore, input constraints are handled by estimating a saturated scaling. A spring, mass, and damper system is used to demonstrate the controller performances via simulation results.  相似文献   

17.
    
A neuroadaptive output feedback control architecture for nonlinear nonnegative dynamical systems with input amplitude and integral constraints is developed. Specifically, the neuroadaptive controller guarantees that the control amplitude as well as the integral of the control input over a given time interval are constrained, and the physical system states remain in the nonnegative orthant of the state space. The proposed approach is used to control the infusion of the anesthetic drug propofol for maintaining a desired constant level of depth of anesthesia for noncardiac surgery in the face of infusion rate constraints and an integral drug dosing constraint over a specified time period. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

18.
    
In this article, the tracking control problem is investigated for a class of nonlinear systems in the presence of unknown disturbance, input saturation, actuator fault, and unknown control coefficient. A novel disturbance observer-based adaptive fault-tolerant tracking control strategy is proposed with regard to nonlinear systems. Based on the Gaussian error function, the auxiliary dynamic system is designed to offset effects caused by the input saturation. Moreover, the Nussbaum-type function is employed to avert control singularity and deal with the unknown control coefficient. A theoretical analysis indicates that the boundedness of all signals in the closed-loop system can be guaranteed. Finally, two examples with one concerning the dynamic point-the-bit rotary steerable drilling tool system are given to confirm the validity of the method.  相似文献   

19.
    
A robust adaptive steering control method is proposed to solve the control problem of the unmanned surface vehicle (USV) with uncertainties, unknown control direction, and input saturation. In the controller design process, the adaptive fuzzy system is incorporated into dynamic surface control (DSC) to approximate the uncertainty term induced by external environmental disturbances and model parameters. Then, the Nussbaum function is used to eliminate the requirement for a priori knowledge of the control direction. Besides, to handle the input saturation, the adaptive fuzzy DSC is extended by a second‐order nonlinear filter and antisaturation auxiliary function to compensate for the magnitude and rate saturation of the rudder. All signals of the closed‐loop system are proven to be uniformly ultimately bounded (UUB) by Lyapunov theorem and the Lemma of Nussbaum gain, and the course error can converge to a small neighborhood of zero through choosing design parameters appropriately. Finally, simulation results and comprehensive comparisons are shown for the USV course system, which is demonstrative of the proposed controller's effectiveness and robustness.  相似文献   

20.
    
This paper presents neural networks (NNs) adaptive controller for an uncertain fractional-order nonlinear system in strict-feedback form, subject to input saturation, unavailable states for measurement, and external disturbances. The fractional-order adaptive laws are derived based only on the output tracking error thanks to the implementation of the strictly positive real (SPR) property, differently from the existing results in the literature of fractional-order strict-feedback systems where all system states are used in the adaptive laws. The proposed design approach addresses the nonaffine nature of the control input due to saturation nonlinearity by using the mean value theorem and follows a nonrecursive design by using a state transformation where the advantage is twofold. First, it eliminates the explosion complexity found in back-stepping control-based approaches design, and second, it reduces the approximators units and parameters in controller implementation. Furthermore, an observer is introduced to estimate the unavailable newly defined states, and then an output adaptive feedback control design is ensured. An NN is used to approximate the unknown ideal control law, and an auxiliary control term is appended to deal with saturation effect, unknown disturbance, and approximation errors. The tracking error is proved to converge asymptotically to a bounded set using the Lyapunov theory. Simulation results on three examples show the effectiveness of the proposed approach.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号