Adaptive nonlinear model predictive control design of a flexible-link manipulator with uncertain parameters

This paper presents a novel adaptive nonlinear model predictive control design for trajectory tracking of flexible-link manipulators consisting of feedback lineariza-tion, linear model predictive control, and unscented Kalman filtering. Reducing the nonlinear system to a linear system by feedback linearization simplifies the optimization prob-lem of the model predictive controller significantly, which, however, is no longer linear in the presence of parame-ter uncertainties and can potentially lead to an undesired dynamical behaviour. An unscented Kalman filter is used to approximate the dynamics of the prediction model by an online parameter estimation, which leads to an adaptation of the optimization problem in each time step and thus to a better prediction and an improved input action. Finally, a detailed fuzzy-arithmetic analysis is performed in order to quantify the effect of the uncertainties on the control structure and to derive robustness assessments. The control structure is applied to a serial manipulator with two flexible links containing uncertain model parameters and acting in three-dimensional space.     

Achievement of chaotic synchronization trajectories of master–slave manipulators with feedback control strategy

This paper addresses a master-slave synchro- nization strategy for complex dynamic systems based on feedback control. This strategy is applied to 3-DOF pla- nar manipulators in order to obtain synchronization in such complicated as chaotic motions of end-effectors. A chaotic curve is selected from Duffing equation as the trajectory of master end-effector and a piecewise approximation method is proposed to accurately represent this chaotic trajectory of end-effectors. The dynamical equations of master-slave manipulators with synchronization controller are derived, and the Lyapunov stability theory is used to determine the stability of this controlled synchronization system. In numer- ical experiments, the synchronous motions of end-effectors as well as three joint angles and torques of master-slave manipulators are studied under the control of the proposed synchronization strategy. It is found that the positive gain matrix affects the implementation of synchronization con- trol strategy. This synchronization control strategy proves the synchronization＇s feasibility and controllability for com- plicated motions generated by master-slave manipulators.     

线性反馈抑制螺旋波

A class of excitable media described by the Fitzhugh-Nagumo equation is investigated. Based on the stable and self adaptive theory, the error between the systems grid variables and the standard sampling of the periodical signal or constant signal was feed back into the system both globally and locally. When the controller was then shut off, automatically, the whole system became homogeneous. Additionally, the scheme was tested under noisy conditions. The numerical simulations results demonstrate its effectiveness. The system reached a homogeneous state and a spiral wave was converted into a target wave, resulting in a wonderful pattern emerging using a different controller. The scheme proved robust in resisting the effects of noise.     

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对EAST装置偏滤器位形的放电中发生的垂直位移不稳定性的全过程进行了模拟,计算了磁轴垂直位移及垂直位移不稳定性的增长率。模拟的结果与实验结果符合得较好。     

模糊时滞系统的输出反馈控制器设计

利用模糊T-S模型对一类非线性时滞系统进行建模;在此基础上,设计出了模糊静态输出反馈控制器和模糊动态输出反馈控制器,并利用Lyapunov-Razumikhin引理和线性矩阵不等式证明了系统渐近稳定的充分条件,通过求解一系列线性矩阵不等式,得到了反馈增益矩阵。     

A note on oligopoly exploitation of common-pool renewable resources

This note derives the linear Feedback Nash equilibrium of a differential oligopoly game of exploitation of a common-pool renewable resource, and compares and contrasts it with social optimum. The case of regulated entry by means of a license fee is also considered. Two main results are derived. First, the steady-state oligopoly price can be increasing in the (exogenously given) number of firms. Second, an optimal license fee exists that induces the (endogenously given) number of firms to behave efficiently.     

Control of AMIRA’s ball and beam system via improved fuzzy feedback linearization approach

This paper first studies the tracking and almost disturbance decoupling problem of nonlinear AMIRA’s ball and beam system based on the feedback linearization approach and fuzzy logic control. The main contribution of this study is to construct a controller, under appropriate conditions, such that the resulting closed-loop system is valid for any initial condition and bounded tracking signal with the following characteristics: input-to-state stability with respect to disturbance inputs and almost disturbance decoupling, i.e., the influence of disturbances on the L₂ norm of the output tracking error can be arbitrarily attenuated by changing some adjustable parameters. One example, which cannot be solved by the first paper on the almost disturbance decoupling problem, is proposed in this paper to exploit the fact that the tracking and the almost disturbance decoupling performances are easily achieved by our proposed approach. The simulation results show that our proposed approach has achieved the almost disturbance decoupling performance perfectly.     

《聚合物加工原理》多元化题库的构建及实施效果

《聚合物加工原理》是高分子材料成型加工专业的核心课程。该课程具有理论性与实践性并重,课程知识点多、涉及面广等特点,仅凭借教材章末问答式练习题为基础的作业布置、回收与批改模式,很难让学生全面理解进而掌握课程核心内容并最终学好该课程。结合课程教学需要与高分子材料加工的专业特色,本文提出从试题内容、考察类型与知识层次三个角度构建多元化课程题库并以课堂作业、阶段性测验、实践环节思考题与社会实践课题等多种形式引入教学活动,在教学过程中逐渐形成了题库应用、学生、教师相互反馈的作业模式。通过对比引入题库前后学生的学习效果,发现题库的引入不仅能够客观而规范地了解学生对所学知识的理解掌握程度,便于教师及时调整教学内容;而且有利于学生精确把握知识难点与重点。多层次的练习培养了学生运用理论基础解决实际问题的能力,增强了开展科研活动的兴趣,综合提升了学习效果。     

Time-delay identification for vibration systems with multiple feedback

An approach for time-delay identification is pro-posed in multiple-degree-of-freedom (MDOF) linear sys-tems with multiple feedback. The applicability of the approach is discussed in detail. Based on the characteris-tics of frequency domain in feedback controlled system with multiple time-delays, this paper proposes a time-delay iden-tification approach, which is based on the pseudo impedance function of reference point. Treating feedback time-delays as the“frequencies”of the oscillation curve, the time-delays can be obtained from the“frequencies”of the curve. Numerical simulation is conducted to validate the proposed approach. The application scope of the approach is discussed with regard to different forms of feedback.     

Lyapunov type functions for classes of autonomous parabolic feedback control problems and applications

In this note we provide sufficient conditions for the existence of a Lyapunov function for a class of parabolic feedback control problems. The results are applied to the long-time behavior of state functions for the following problems: (i) a model of combustion in porous media; (ii) a model of conduction of electrical impulses in nerve axons; and (iii) a climate energy balance model.