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为提高移动机器人对特定轨迹的重复跟踪能力,提出了采用开闭环PD型迭代学习控制算法对移动机器人进行轨迹跟踪控制的方法。建立了包含外界干扰的非完整约束条件下的轮式移动机器人运动学模型,给出了系统的控制算法和控制结构。仿真结果表明,采用开闭环PD型迭代学习控制算法对轨迹跟踪是可行有效的,收敛速度优于其他迭代学习算法。 相似文献
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针对P型迭代学习算法对初始偏差和输出误差扰动敏感,以及PD型迭代学习算法容易放大系统噪声,降低系统鲁棒性的问题,研究了具有任意有界扰动及期望输出的重复运行非线性时变系统的PD型迭代学习跟踪控制算法.利用迭代学习过程记忆的期望轨迹、期望控制以及跟踪误差,给出基于变批次遗忘因子的学习控制器设计,并借助λ范数理论和Bellman-Gronwall不等式,讨论保证闭环跟踪系统批次误差有界的学习增益存在的充分必要条件,及分析控制算法的一致收敛性.本算法改善了系统的鲁棒性和动态特性,单关节机械臂的跟踪控制仿真验证了方法的有效性. 相似文献
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为解决迭代学习过程中的任意迭代初值和迭代收敛理论证明难的问题,本文构造了一种轨迹跟踪误差初值恒位于滑模面内的时变终端滑模面,将轨迹跟踪误差初值不为零的轨迹跟踪控制问题转换为滑模面初值恒为零的滑模面跟踪控制问题,建立了任意迭代初值与相同迭代初值的迭代学习控制理论连接桥梁.本文提出一种基于时变滑模面的比例–积分–微分(PID)型闭环迭代学习控制策略,基于压缩映射原理证明了迭代学习的收敛性,给出了迭代收敛条件.时变终端滑模面经有限次迭代学习收敛到零,达到轨迹跟踪误差最终稳定在时变滑模面内的目的;Lyapunov稳定理论证明了位于滑模面内的轨迹跟踪误差在有限时间内收敛到原点,达到轨迹局部精确跟踪目的.随机初态下的工业机器人轨迹跟踪控制数值仿真验证了本文方法的有效性和系统对外部强干扰的鲁棒性. 相似文献
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针对一类线性时不变系统,讨论存在固定初始偏移时的学习控制问题,提出带有反馈辅助项的比例微分(proportion differentiation,PD)型学习控制算法,分析所提算法在Lebesgue-p范数意义下的单调收敛性,获得对期望轨迹的渐近跟踪结果.进一步地,为获得系统输出对期望轨迹的完全跟踪,给出带有初始修正策略的比例–积分–微分(proportion multiple integration differentiation,PMID)型学习律,并给出了所提学习算法的单调收敛性能分析结果.最后,通过数值结果,验证了所提学习算法的跟踪性能和单调收敛性能. 相似文献
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针对一般连续系统的迭代学习控制问题进行了讨论,通过对常用的P型迭代学习控制算法的分析,在分析比较P型、PD型迭代学习控制律存在问题的基础上,提出了一种新型的迭代学习控制算法,利用误差信号以及相邻两次误差的差值信号对系统控制律进行逐次修正,既能避免PD型迭代算法由于微分作用而出现的不良影响,又可以充分地利用了系统已保存的有效信息,从而实现良好的跟踪效果以及较快的跟踪收敛速度,最后通过对一非线性连续系统的仿真,结果验证了算法相对于传统P算法的有效性与优越性. 相似文献
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离散非线性时变系统开闭环PI型迭代学习控制律及其收敛性 总被引:2,自引:0,他引:2
对于具有重复运动性质的对象,迭代学习控制是一种有效的控制方法.针对一类
离散非线性时变系统在有限时域上的精确轨迹跟踪问题,提出了一种开闭环PI型迭代学习
控制律.这种迭代律同时利用系统当前的跟踪误差和前次迭代控制的跟踪误差修正控制作
用.给出了所提出的学习控制律收敛的充分必要条件,并采用归纳法进行了证明.最后用仿真
结果对收敛条件进行了验证. 相似文献
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模糊学习控制在SCARA机器人轨迹跟踪中的应用 总被引:2,自引:0,他引:2
模糊学习控制以模糊控制提供反馈机制为主体,辅以迭代学习控制提供前馈补偿机制,来实现对期望轨迹的完全跟踪.把模糊学习控制应用于SCARA机器人的轨迹跟踪.仿真试验表明,该方法具有简单实用、跟踪精度高、学习速度快等优点. 相似文献
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In this paper, a novel direct adaptive fuzzy control approach is presented for uncertain nonlinear systems in the presence of input saturation. Fuzzy logic systems are directly used to tackle unknown nonlinear functions, and the adaptive fuzzy tracking controller is constructed by using the backstepping recursive design techniques. To overcome the problem of input saturation, a new auxiliary design system and Nussbaum gain functions are incorporated into the control scheme, respectively. It is proved that the proposed control approach can guarantee that all the signals of the resulting closed-loop system are semi-globally uniformly ultimately bounded (SGUUB), and the tracking error converges to a small neighborhood of the origin. A simulation example is included to illustrate the effectiveness of the proposed approach. Two key advantages of the scheme are that (i) the direct adaptive fuzzy control method is proposed for uncertain nonlinear system with input saturation by using Nussbaum function technique and (ii) The number of the online adaptive learning parameters is reduced. 相似文献
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A novel fuzzy terminal sliding mode control (FTSMC) scheme is proposed for position tracking of a class of second-order nonlinear uncertain system. In the proposed scheme, we integrate input-output linearization technique to cancel the nonlinearities. By using a function-augmented sliding hyperplane, it is guaranteed that the output tracking error converges to zero in finite time which can be set arbitrarily. The proposed scheme eliminates reaching phase problem, so that the closed-loop system always shows invariance property to parameter uncertainties. Fuzzy logic systems are used to approximate the unknown system functions and switch item. Robust adaptive law is proposed to reduce approximation errors between true nonlinear functions and fuzzy systems, thus chattering phenomenon can be eliminated. Stability of the proposed control scheme is proved and the scheme is applied to an inverted pendulum system. Simulation studies are provided to confirm performance and effectiveness of the proposed control approach. 相似文献
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A novel fuzzy terminal sliding mode control (FTSMC) scheme is proposed for position tracking of a class of second-order nonlinear uncertain system. In the proposed scheme, we integrate input-output linearization technique to cancel the nonlinearities. By using a function-augmented sliding hyperplane, it is guaranteed that the output tracking error converges to zero in finite time which can be set arbitrarily. The proposed scheme eliminates reaching phase problem, so that the closed-loop system always shows invariance property to parameter uncertainties. Fuzzy logic systems are used to approximate the unknown system functions and switch item. Robust adaptive law is proposed to reduce approximation errors between true nonlinear functions and fuzzy systems, thus chattering phenomenon can be eliminated. Stability of the proposed control scheme is proved and the scheme is applied to an inverted pendulum system. Simulation studies are provided to confirm performance and effectiveness of the proposed control approach. 相似文献
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Wen-Jun Cao Jian-Xin Xu 《Automatic Control, IEEE Transactions on》2002,47(5):824-830
A learning variable structure control (LVSC) approach is originated to obtain the equivalent control of a general class of multiple-input-multiple-output (MIMO) variable structure systems under repeatable control tasks. LVSC synthesizes variable structure control (VSC) as the robust part which stabilizes the system, and learning control (LC) as the "plug-in" intelligent part which completely nullifies the effects of the matched uncertainties on tracking error. Rigorous proof based on energy function and functional analysis shows. that the tracking error sequence converges uniformly to zero, and that the bounded LC sequence converges to the equivalent control almost everywhere 相似文献
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大部分模糊控制器不具有适应控制对象变化的能力,基于此设计一种自调整因子模糊控制器,并针对机械臂长时间重复操作导致运动精确度下降这一类问题,结合迭代学习控制方法,提出一种自调整因子模糊PD迭代学习控制方法;以双关节机械臂为研究对象,利用Fuzzy工具箱编写模糊控制规则,通过系统产生的误差以及误差的变化率作为模糊控制器的输入量调整模糊系统中的量化因子和比例因子,实现模糊规则的更新和对迭代学习控制中的PD参数的实时调整,系统的自适应性得到提高,并在Simulink中进行机械臂的运动控制实验,仿真结果表明,所提控制方法最终产生的误差可以精确到0.0001 rad,同时在进行第2次迭代时关节角度和角速度误差收敛基本趋于零,整体的控制效果较好。 相似文献
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Adaptive fuzzy tracking control of nonlinear time-delay systems with unknown virtual control coefficients 总被引:1,自引:0,他引:1
In this paper, a novel adaptive fuzzy control scheme is proposed for a class of uncertain single-input and single-output (SISO) nonlinear time-delay systems with the lower triangular form. Fuzzy logic systems are used to approximate unknown nonlinear functions, then the adaptive fuzzy tracking controller is constructed by combining Lyapunov-Krasovskii functionals and the backstepping approach. The proposed controller guarantees uniform ultimate boundedness of all the signals in the closed-loop system, while the tracking error converges to a small neighborhood of the origin. An advantage of the proposed control scheme lies in that the number of adaptive parameters is not more than the order of the systems under consideration. Finally, simulation studies are given to demonstrate the effectiveness of the proposed design scheme. 相似文献
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Fuzzy-identification-based adaptive backstepping control using a self-organizing fuzzy system 总被引:1,自引:0,他引:1
Pin-Cheng Chen Chun-Fei Hsu Tsu-Tian Lee Chi-Hsu Wang 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2009,13(7):635-647
In this paper, a fuzzy-identification-based adaptive backstepping control (FABC) scheme is proposed. The FABC system is composed
of a backstepping controller and a robust controller. The backstepping controller, which uses a self-organizing fuzzy system
(SFS) with the structure and parameter learning phases to on-line estimate the controlled system dynamics, is the principal
controller, and the robust controller is designed to dispel the effect of approximation error introduced by the SFS. The developed
SFS automatically generates and prunes the fuzzy rules by the proposed structure adaptation algorithm and the parameters of
the fuzzy rules and membership functions tunes on-line in the Lyapunov sense. Thus, the overall closed-loop FABC system can
guarantee that the tracking error and parameter estimation error are uniformly ultimately bounded; and the tracking error
converges to a desired small neighborhood around zero. Finally, the proposed FABC system is applied to a chaotic dynamic system
to show its effectiveness. The simulation results verify that the proposed FABC system can achieve favorable tracking performance
even with unknown controlled system dynamics. 相似文献
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