Observer design for a class of MIMO nonlinear systems

A simple observer is proposed for a large class of MIMO nonlinear systems which includes many physical models. The main characteristic of the proposed observer lies in the easiness of its implementation and calibration. Indeed, the gain of this observer does not necessitate the resolution of any dynamical system and its expression is given. Moreover, its calibration is achieved through the choice of a single parameter. A simulation example is given in order to illustrate the performance of the proposed observer.     

Observer design for systems with multivariable monotone nonlinearities

Globally convergent observers are designed for a class of systems with multivariable nonlinearities. The approach is to represent the observer error system as the feedback interconnection of a linear system and a state-dependent multivariable nonlinearity. We first extend an earlier design (Automatica 37 (12) (2001) 1923) to multivariable nonlinearities, satisfying an analog of the scalar nondecreasing property. Next, we exploit the structure of the nonlinearity to relax the positive real restriction on the linear part of the observer error system. This relaxed design renders the feasibility conditions less restrictive, and widens the applicability of the observer, as illustrated with examples. Finally, output nonlinearities are studied and the design is extended to be adaptive in the presence of unknown parameters.     

Observer design via Immersion and Invariance for vision-based leader-follower formation control

The paper introduces a new vision-based range estimator for leader-follower formation control, based upon the Immersion and Invariance (I&I) methodology. The proposed reduced-order nonlinear observer is simple to implement, easy to tune and achieves global asymptotical convergence of the observation error to zero. Observability conditions for the leader-follower system are analytically derived by studying the singularity of the Extended Output Jacobian. The stability of the closed-loop system arising from the combination of the range estimator and an input-state feedback controller is proved by means of Lyapunov arguments. Simulation experiments illustrate the theory and show the effectiveness of the proposed designs.     

浅析Observer模式在GIS软件设计中的应用

面向对象方法仅仅从问题域的离散抽象很难达到高内聚和低耦合,设计模式的出现和广泛应用为解决这个问题提供了有效的方法.探讨了Observer模式的基本原理以及在GIS软件设计中的应用,并在具体实践中做了有益尝试.实践证明了设计模式在改善软件的灵活性和适应性方面所发挥的积极作用.     

Observer design for range and orientation identification

A reduced-order globally convergent observer to estimate the depth of an object projected on the image plane of a camera is presented, assuming that the object is planar or has a planar surface and the orientation of the plane is known. A locally convergent observer can be obtained when the plane unit normal is unknown, and the latter is estimated together with the depth of the object. The observer exploits the image moments of the object as measured features. The estimation is achieved by rendering attractive and invariant a manifold in the extended state space of the system and the observer. The problem is reduced to the solution of a system of partial differential equations. The solution of the partial differential equations can become a difficult task, hence it is shown that this issue can be resolved by adding to the observer an output filter and a dynamic scaling parameter.     

A finite element approach for multiphase fluid flow in porous media

The main scope of this work is to carry out a mathematical framework and its corresponding finite element (FE) discretization for the partially saturated soil consolidation modelling in presence of an immiscible pollutant. A multiphase system with the interstitial voids in the grain matrix filled with water (liquid phase), water vapour and dry air (gas phase) and with pollutant substances, is assumed. The mathematical model addressed in this work was developed in the framework of mixture theory considering the pollutant saturation-suction coupling effects. The ensuing mathematical model involves equations of momentum balance, energy balance and mass balance of the whole multiphase system. Encouraging outcomes were achieved in several different examples.     

Robust State‐and‐Disturbance Observer Design for Linear Non‐minimum‐phase Systems

When there are external disturbances acting on the system, the conventional Luenberger observer design for state estimation usually results in a biased state estimate. This paper presents a robust state and disturbance observer design that gives both accurate state and disturbance estimates in the face of large disturbances. The proposed robust observer is structurally different from the conventional one in the sense that a disturbance estimation term is included in the observer equation. With this disturbance estimation term, the robust observer design problem is skillfully transformed into a disturbance rejection control problem. We then can utilize the standard H_∞ control design tools to optimize the robust observer between the disturbance rejection ability and noise immune ability. An important advantage of the proposed robust observer is that it applies to both minimum‐phase systems and non‐minimum phase systems.     

Adjoint-based optimization of multi-phase flow through porous media – A review

The recovery of oil from subsurface reservoirs often requires the injection of water or gas to maintain reservoir pressure and to displace the oil from injection to production wells. The design of an economically optimal recovery strategy is usually based on ’reservoir simulation’, i.e. large-scale numerical simulation of the flow of multi-phase fluids through strongly heterogeneous porous media with uncertain coefficients. Control of the recovery process is through prescribing time-varying pressures or flow rates in the wells. Efficient methods to optimize the recovery strategy make use of gradients of an economic objective function with respect to the well controls at every time step. These can be obtained efficiently with the aid of adjoint-based techniques. Constraints, in particular those that involve states (reservoir pressures or saturations) or outputs (measured well pressures or rates) require special treatment. Uncertainty in the coefficients can be incorporated through robust optimization over an ensemble of models. The limited controllability of the reservoir states offers scope for reduced-order modeling using techniques like proper orthogonal decomposition. ‘Closed-loop’ optimization can be performed through frequent repetition of the optimization during the producing life of the field in combination with updating the of the model coefficients based on production measurements. Moreover, an emerging technology is the operational use of model-based optimization which requires a combination of long-term and short-term objectives through multi-level optimization strategies.     

Stabilizing compensator design for uncertain nonlinear systems

An observer-based control scheme is proposed for exponentially stabilizing a class of uncertain nonlinear systems. The control and observer gain expressions given in this paper resemble those used in variable-structure designs but they are continuous in nature resulting in a simple analysis of stability.     

Observer with linear error dynamics for nonlinear multi-output systems

Based upon nonlinear state coordinate transformations and a condensed dual Brunovský form for multi-output systems, a method for designing nonlinear state observers with linear error dynamics is presented. Necessary and sufficient conditions are provided for identifying the class of nonlinear systems for which state observers with linear error dynamics can be obtained.     

Observer模式分析及其在．net中的改进

介绍了设计模式的概念，分析了一种常见的模式一观察者模式。给出了观察者模式的传统的实现方法，并分析了它的缺点。利用．net框架中的代理和事件技术对观察者模式进行了改进，从而简化了程序的开发难度和出现错误的概率，提高了系统的灵活性。     

Globally Asymptotic and Locally Exponential Tracking Observer/Controller for a Relatively Large Class of Systems with Hysteresis

In this work, we present an observer and controller for a class of plants with a relatively large class of hysteresis. For these considered classes of hysteretic systems, we propose and present an observer/controller that estimates or observes the hysteresis state and drives the position tracking error to zero. We prove that the combined tracking error and observer errors converge to zero both globally asymptotically and locally exponentially.     

带有不可测量扰动的广义双线性系统状态观测器设计及故障诊断

讨论了存在未知扰动情况下,广义双线性系统全阶状态观测器的存在条件及其设计方法。得到的观测器可直接用于解决广义双线性系统的故障诊断问题,最后的数值例子说明了设计步骤。仿真结果验证了设计的有效性。     

Observer design for generalized state space systems with unknown inputs

The following four major aspects for the observer design problem for generalized state space systems with unknown inputs are resolved: Necessary and sufficient conditions for the problem to have a solution, the order of the minimal observer, the properties of the closed-loop system (separation principle) and general analytical expressions of the minimal order observer matrices. All above results are first in the field.     

Observer模式与Command模式在条码采集系统中的应用研究

结合条码采集系统的设计与开发,探讨了设计模式中的Observer模式与Command模式,结果表明：使用Observer模式进行数据管理,使用Command模式进行功能管理,可以增强系统代码的重用性、灵活性和模块化,提高了系统开发效率。     

An analysis and design method for a class of nonlinear systems with nested saturations

This paper is concerned with the analysis and design of a class of nonlinear systems subject to nested saturations. The proposed controller incorporates both an extended state observer (ESO), which is utilised to estimate the nonlinear dynamics of the plant, as well as a set of observer-based feedbacks. We first present analysis results for systems with nonlinear ESOs and show that local stabilisation can be achieved in a region including the origin. Then, in the case that the ESO is in linear form (LESO), the conditions for determining the estimate of the domain of attraction of the resulting closed-loop system are formulated as a convex optimisation problem. A linear matrix inequality based algorithm is then established to design the feedback gains and the LESO gain. An illustrative example is given to show the effectiveness of the proposed approach.     

旋转环式多相流量计的研制

介绍一种用于测量多相流的旋转环式流量计。阐述了其工作原理 ,分析了旋转活塞的工况 ,并探讨了研制过程中遇到的最为关键的活塞材料选型与制造工艺问题     

Decomposition schemes and acceleration techniques in application to production–assembly–distribution system design

The purpose of this paper is to study several schemes for applying Dantzig–Wolfe decomposition (DWD) to the production–assembly–distribution system design problem (PADS). Each scheme exploits selected embedded structures. The research objective is to enhance the rate of DWD convergence in application to PADS through formulating a rationale for decomposition by analyzing potential schemes, adopting acceleration techniques, and assessing the impacts of schemes and techniques computationally. Test results provide insights that may be relevant to other applications of DWD.