CLF based designs with robustness to dynamic input uncertainties

The problem of robust stabilization of nonlinear systems in the presence of input uncertainties is of great importance in practical implementation. Stabilizing control laws may not be robust to this type of uncertainty, especially if cancellation of nonlinearities is used in the design. By exploiting a connection between robustness and optimality, “domination redesign” of the control Lyapunov function (CLF) based Sontag's formula has been shown to possess robustness to static and dynamic input uncertainties. In this paper we provide a sufficient condition for the domination redesign to apply. This condition relies on properties of local homogeneous approximations of the system and of the CLF. We show that an inverse optimal control law may not exist when these conditions are violated and illustrate how these conditions may guide the choice of a CLF which is suitable for domination redesign.     

Riccati代数方程中矩阵P与R,Q关系的研究

本文对Riccati代数方程中矩阵P与R,Q的关系进行了研究.给出了矩阵R、Q变化时方程解P的变化范围.这对最优控制、鲁棒控制、容错控制及H∞控制等有着重要的意义.     

A global stability result in network flow control

This paper concerns recently proposed algorithms for network flow control, where source transmission rates are chosen based on an individual utility function and a network price signal propagated from the links. Link prices are, in turn, dynamically updated based on overall link congestion. In particular, we consider here the second-order update law of Athuraliya et al. [IEEE Network 15 (3) (2001) 48–53], which has attractive features in equilibrium: full link utilization and no backlog. Using a non-linear, continuous-time model which enforces non-negativity constraints in prices and backlogs, we prove the global asymptotic stability of the equilibrium, by means of a Lyapunov argument.     

Optimal Compensation by Linear Robust Control for Uncertain Systems

Linear control design of nonlinear discrete-time uncertain systems with (possibly fast) uncertain parameters is considered. The possible uncertainty bound needs to be within a threshold. The threshold in turn is dependent on a design parameter. To achieve the maximum threshold by an optimal choice of the design parameter, a constrained optimization problem is proposed. The optimal compensation of the uncertainty is in general a partial compensation.     

Global tracking control of underactuated ships by Lyapunov's direct method

This paper studies the global tracking problem for an underactuated ship with only two propellers. Under sufficient conditions of persistent excitation, two constructive solutions are proposed by application of Lyapunov's direct method. Both solutions exploit the inherent cascade interconnected structure of the ship dynamics and generate explicit Lyapunov functions. A common feature of the second solution and the recent cascade approach of Lefeber (Tracking control of nonlinear mechanical systems, Ph.D. Thesis, University of Twente, 2000) is that global exponential tracking is achieved, but at the expense of transient performance. Extension to unmeasured thruster dynamics is also considered. Simulation results validate the proposed tracking methodology.     

Stability issues for dynamic traffic assignment

This paper explores stability issues for operational route guidance control strategies for vehicular traffic networks equipped with advanced information systems, and develops a general procedure for the stability analysis of the associated dynamic traffic assignment (DTA) problems. The route guidance control strategies are modeled as dynamical systems, and the associated solution procedure enables computational tractability for real-time deployment. An important study insight is that the Lyapunov functions for the route guidance control models are their corresponding objective functions under DTA. This overcomes the key difficulty of constructing meaningful Lyapunov functions for DTA problems.     

A nonlinear robust HVDC control for a parallel AC/DC power system

In this paper, a parallel AC/DC power system is investigated, and a nonlinear robust controller is proposed to improve transient stability of the power system and to damp out any prolonged oscillation after a fault is cleared. Lyapunov's direct method is used to synthesize the control, and asymptotic stability of the closed loop system and improved dynamic performance are shown by both theoretical proof and simulation results.     

Novel decentralized adaptive strategies for the synchronization of complex networks

This paper is concerned with the analysis of the synchronization of networks of nonlinear oscillators through an innovative local adaptive approach. In particular, time-varying feedback coupling gains are considered, whose gradient is a function of the local synchronization error over each edge in the network. It is shown that, under appropriate conditions, the strategy is indeed successful in guaranteeing the achievement of a common synchronous evolution for all oscillators in the network. The theoretical derivation is complemented by its validation on a set of representative examples.     

足尺人造板力学性能自动检测样机控制系统研究

为了快速检测足尺人造板的力学性能,自行研制了检测样机,该样机的控制系统采用PC＋NI运动控制卡的结构。硬件主要由PC机、NI运动控制卡、电机、接近开关、传感器等组成,系统软件使用图形化编程语言Labview为开发平台,对多轴运动控制系统进行开发。重点阐述了控制原理、如何提高系统的稳定性及抗干扰性。结果表明,该系统人机界面友好,开发周期短,易于操作,具有很好的稳定性和抗干扰性。     

具有输入饱和特性的中型足球机器人运动控制研究

研究了具有输入饱和特性的全自主中型足球机器人的运动控制问题,建立了足球机器人的运动学模型,基于Lyapunov稳定性条件研究了足球机器人对足球跟踪的自主控制算法,实现了足球机器人在赛场上的高精度运动控制,实验进一步证明了算法的鲁棒性。     

New direct lyapunov-type method for studying synchronization problems

A new approach of the Lyapunov type is presented for the stability analysis of a class of time invariant, nonlinear dynamical systems, which are characterized by a periodic nonlinearity, and the existence of an infinite number of stationary states. In particular, the method can be applied for studying transient stability problems in power systems, and the synchronization of phase lock circuits. Frequency criteria are developed for the convergence of all solutions to an equilibrium state, and a procedure, based on these criteria, is outlined for constructing stability regions for a collection of neighboring equilibria. When applied to power—or phase lock systems, these regions can be interpreted as synchronization regions within an arbitrary, given number of cycles. Also, some new results are obtained with respect to synchronization conditions within the first cycle.     

Stability and boundedness in terms of two measures for nonlinear impulsive control systems

In this paper we study stability and boundedness in terms of two measures for impulsive control systems. By using variational Lyapunov method, a new variational comparison principle and some criteria on stability and boundedness are obtained. An example is presented to illustrate the efficiency of proposed result.     

Convergence in mean for ELS-based adaptive control

Almost sure global convergence results are available for stochastic adaptive control. This note looks at the nontrivial technical details required to ensure corresponding convergence in p-th mean results. Both convergence results are strong but are not implied by the other and so together, almost sure and p-th mean convergence, are stronger than either. The other aim of this paper is to show that the combination of these two forms of convergence results makes the stability results more robust and potentially of more practical significance.     

D型迭代学习控制及其在FNS肢体运动控制系统中的应用

给出了离散系统D－型迭代学习控制算法收敛的一种充分条件,并加以证明。采用D型迭代学习控制算法,对基于功能性神肉电刺激的曲腕和曲肘运动进行了临床实验研究,结果表明,D型迭代学习算法改善了FNS肢体运动控制的跟踪性能,曲肘和曲腕运动轨迹平滑、稳定,并且刺激控制脉冲变化平缓,受试者无任何不良生理反应。     

油浸式变压器内部检测球形机器人的深度悬停控制研究

为实现设计的油浸式变压器内部检测机器人在实际作业过程中能针对深度方向某具体点进行观测,对机器人的深度悬停控制进行研究.通过对机器人控制策略的分析,根据水下机器人动力学理论,建立机器人在变压器油特殊介质的动力学模型.基于鲁棒反演控制方法及滑模自适应控制理论,提出一种鲁棒反演滑模控制方法,采用模糊控制器设计滑模面切换增益,以削弱不确定干扰带来的系统抖振,并通过Lyapunov理论分析证明控制器稳定性.解决了机器人在变压器油中因耦合、外界扰动等造成的深度悬停定点过程自旋及抖动问题,仿真及实验表明了所提出控制器的有效性.     

约束非线性系统构造性模型预测控制

研究了连续时间约束非线性系统模型预测控制设计.利用控制Lyapunov函数离线构造单变量可调预测控制器,再根据性能指标在线优化可调参数,其中该参数近似于闭环系统的"衰减率".同时,控制Lyapunov函数保证了算法的可行性和闭环系统的稳定性.最后通过数值仿真验证了该算法的有效性.     

非线性定常系统及其定常Lyapunov函数的多项式等价类

非线性定常系统及其定常Ｌｙａｐｕｎｏｖ函数的多项式等价类苗原李春文杜继宏（清华大学自动化系北京１０００８４）关键词稳定性,非线性多项式系统,李亚普诺夫函数．收稿日期１９９５－０５－１６１引言李亚普诺夫第二方法作为处理系统稳定性问题的最主要的方法之一已...