Conditions on input disturbance suppression for multivariable nonlinear systems on the basis of feedforward passivity

In this paper, we consider the problem of input disturbance suppression for nonlinear systems based on feedforward passivity. First, we show that integral control can sufficiently suppress a class of slowly variant (including constant) input disturbance and track constant references provided certain closed-loop stability is achieved. Then, sufficient conditions of integral controllability for nonlinear processes are presented. These conditions are further relaxed by using an input and output transformation.     

A population dynamics approach for the water distribution problem

The water distribution system (WDS) is composed of several elements, where flow control is one of the most important components needed in order to provide a satisfactory level of service. In order to achieve an adequate level of water in the distribution tanks, we need to dynamically control the flow. Here, we propose a population dynamics approach in order to control tanks, by allocating in them the maximum uniform volume. The feedback interconnected systems reach a stable equilibrium point for both approaches presented (i.e. replicator and supply dynamics), and more specific an asymptotically stable equilibrium point for the replicator dynamics case. The stability analysis uses some passivity concepts and classic Lyapunov theory for a closed-loop system that combines the population dynamics (controller), and the WDS (process). We show via simulations the operation under different scenarios.     

基于自适应无源化的蔡氏电路混沌同步

根据蔡氏电路混沌系统的特点,得出了蔡氏电路混沌驱动系统与响应系统的误差系统.根据混沌系统的同步条件,可将混沌的同步问题转化成为误差系统的稳定性问题,即使混沌同步误差系统渐近稳定以实现混沌同步控制.针对蔡氏电路混沌系统的误差系统,采用自适应无源化方法,设计了使同步误差系统渐近稳定的具有自适应功能的反馈镇定器.该控制方法实现了2个蔡氏电路混沌系统同步,仿真研究验证了该方法的有效性.     

Passivity‐based state synchronization of homogeneous multiagent systems via static protocol in the presence of input saturation

This paper studies semiglobal and global state synchronization of homogeneous multiagent systems with partial‐state coupling (ie, agents are coupled through part of their states) via a static protocol. We consider 2 classes of agents, ie, G‐passive and G‐passifiable via input feedforward, which are subjected to input saturation. The proposed static protocol is purely decentralized, ie, without an additional channel for the exchange of controller states. For semiglobal synchronization, a static protocol is designed for an a priori given set of network graphs with a directed spanning tree. In other words, the static protocol only needs rough information on the network graph, ie, a lower bound for the real part and an upper bound for the modulus, of the nonzero eigenvalues of the corresponding Laplacian matrix. Whereas for global synchronization, only strongly connected and detailed balanced network graphs are considered. In this case, for G‐passive agents, the static protocol does not need any network information, whereas for G‐passifiable agents via input feedforward, the static protocol only needs an upper bound for the modulus of the eigenvalues of the corresponding Laplacian matrix.     

负载转矩未知时变情形下异步电动机的无源性跟踪控制

应用无源性控制理论和方法,研究了在转子电阻确定已知,负载转矩和期望转矩任意时变的情形下异步电动机期望转矩的渐近跟踪控制问题.首先分析负载已知的情形,然后主要研究了负载转矩时变未知的情形,给出了此时负载转矩的实时估计方法和控制器设计方法.最后进行了仿真验证,证明这样设计的控制器性能良好.     

电网不平衡时电压型PWM整流器混合无源控制

针对国内外电网不平衡时电压型PWM整流器控制策略存在控制结构复杂和控制性能不佳的问题,提出了由直流电压环(PI)与无源电流控制器组成的电压型PWM整流器混合无源控制器。基于整流器的EL(Euler-Lagrange,EL)模型,利用阻尼注入方法设计了无源电流控制器。根据无源电流控制器确定出具有补偿电网不平衡功能的开关函数。该混合无源控制器只需电压、电流的实时值,通过混合无源控制器就可消除或抑制整流器输入电流中的所有谐波且使整流器具有恒定的直流电压;可使整流器具有良好的性能和简单的控制结构。仿真和实验结果表明,电网不平衡时电压型PWM整流器混合无源控制是可行的。     

基于黑盒子方法的GIS内电压互感器高频电路模型的建立

为了研究气体绝缘变电站内的开关操作产生的陡波前过电压(VFTO)通过互感器对二次设备的影响,需要建立它们的高频电路模型。笔者提出了一种基于黑盒子方法的电压互感器(PT)高频电路模型的建立方法。该方法在应用矢量匹配法逼近PT导纳参数矩阵Y(s)的基础上建立了其π型等效电路,然后运用福斯特型RLC电路综合方法实现了该电路模型。为了保证电路模型仿真时的稳定性,对Y(s)的实部进行了无源性修正。由于该方法保证了所建模型的宏观无源性,所以建立的电路模型可以进行稳定、准确的数值仿真。对一个实际PT的测量和仿真计算验证了该方法的有效性。     

一种新的电压型PWM整流器无源控制器设计

为克服现行电压型PWM整流器无源控制器存在的缺点(如负载变化、电源不平衡时存在较大的直流电压稳态误差,系统的响应速度不理想等),基于整流器在两相同步旋转dq坐标系中的欧拉一拉格朗日EL(Euler-Lagrange)数学模型和无源性,通过阻尼注入方法,提出了一种由状态期望稳定平衡点x*、状态x及状态误差xe设计无源控制器的新方法.采用新方法设计的电压型PWM整流器无源控制器,可实现整流器有功电流和无功电流的解耦,使整流器具有更好的动、静态性能,对电源相位、负载扰动具有强的鲁棒性.仿真实验结果表明用新方法设计的电压型PWM整流器无源控制系统性能(如输入电流总谐波扰动THD、直流电压稳态误差、直流电压动态误差、直流电压上升时间及功率因数)优于现行的电压型PWM整流器无源控制系统.     

Improved passivity criterion in haptic rendering: influence of Coulomb and viscous friction

In this paper, a new criterion for passivity of haptic devices is obtained. This criterion creates a relationship between Coulomb friction coefficient, viscous friction coefficient, sampling rate, and the maximum simulated stiffness. The process of derivation of the passivity criterion is described in detail. This criterion is improved compared with other existing criteria and predicts passivity in haptic rendering more accurately. In particular, for speeds of less than 5?cm/s, the new passivity criterion should replace the previous criteria to avoid unwanted vibrations of stiff virtual walls. Analytical and numerical investigations are presented to validate the new criterion. A specific trajectory is designed and the movement of the haptic robot is investigated on this trajectory to validate and compare this passivity criterion with the previous criteria.     

AUV近水面运动非线性观测器设计

针对AUV近水面低速运动中的波浪扰动问题,基于无源性原理设计了一种非线性状态观测器.观测器可以从包含高频运动信号、低频运动信号以及传感器噪声信号的AUV综合运动信号中估计出AUV的低频运动信号以及环境扰动作用力.该观测器克服了传统的线性化Kalman滤波器的缺陷,直接针对AUV的非线性模型进行观测器设计,用李亚普诺夫稳...