一种新的基于自适应观测器中立时滞系统故障估计的设计方法

研究了基于自适应观测器中立时滞系统的故障估计问题. 首先, 本文提出了一种新的快速自适应故障估计算法提升了故障估计的快速性和准确性. 同时, 一个时滞相关的判据用于减少设计过程中的保守性, 特别对于小时滞系统. 然后, 应用线性矩阵不等式技巧, 给出了详细的设计步骤. 最后, 仿真结果验证了所提方法的有效性.     

基于滑模观测器和广义观测器的故障估计方法

针对受未知干扰影响的一类非线性系统,提出一种基于滑模观测器和广义观测器的执行器故障和传感器故障估计方法.首先通过线性变换将原系统解耦为两个降阶的子系统,其中一个子系统受执行器故障和干扰的影响,另一个含有传感器故障和干扰,进一步将后一个子系统转化为广义系统.对两类子系统分别设计滑模观测器和广义观测器,给出估计误差一致最终有界的条件,得到系统状态和未知干扰的估计值.然后,利用等效输出控制原理重构执行器故障,引入干扰补偿保证重构算法的鲁棒性,再根据广义观测器的结果获得传感器故障的估计值.最后,通过计算机仿真验证了本文方法的有效性.     

基于中间观测器的多智能体系统分布式故障估计

针对发生执行器故障的多智能体系统, 论文提出一种新型分布式中间观测器的设计方法, 可以同时估计系统的状态和故障.本文设计的观测器可以应用于严格正实条件和观测器匹配条件不满足的系统.针对多智能体系统的通讯拓扑是有向图和无向图的情况, 分别获得估计误差系统稳定的条件.观测器的参数矩阵可以通过求解线性矩阵不等式(Linear matrix inequality, LMI)计算.针对具有有向拓扑的多智能体系统, 本文方法所需求解的LMI的维数, 等于对单个智能体系统设计观测器所需求解的LMI的维数.这表明应用本文方法进行故障估计时, 计算量不会随着系统中智能体数目的增加而增加.针对多智能体系统通讯拓扑是无向图的情况, 利用Laplacian矩阵的对称性, 可以得到保守性更小的结论.最后, 仿真算例验证了本文方法的有效性.     

多智能体系统的鲁棒故障估计观测器的设计

针对线性变参数多智能体系统设计了有限频域鲁棒故障估计观测器。首先,根据每个智能体的绝对可测输出和相对可测输出建立了每个节点的动力学方程,结合无向通讯拓扑图及拉普拉斯矩阵得到了多智能体系统的动力学方程,通过合适的变换对多智能体系统模型进行了解耦;然后,根据解耦后的系统动力学方程设计了故障估计观测器,并通过优化技术得到了故障估计观测器增益矩阵和优良的鲁棒性能指标;最后,通过微型飞行器纵向飞行运动的例子验证了所设计的故障估计观测器的有效性,及系统参数在一定的范围内发生变动的时候,故障估计观测器依然可以准确的估计系统所发生的故障。     

基于观测器的发电机功角与故障估计

针对发电机功角与故障估计这个问题,提出一种利用观测器的方法.该方法通过对系统数学模型进行状态变换,将数学模型分为含故障与不合故障两部分.对不合故障部分设计观测器,然后经过状态变换可以得到功角信息.在故障估计过程中,通过增广误差系统设计增广观测器可以得到故障的幅值.最后通过Matlab仿真分析,验证基于观测器功角与故障估计方法的有效性,结果表明该方法具有速度快、误差小的优点.     

Robust Fault Diagnosis for Quadrotor UAVs Using Adaptive Thau Observer

A robust Fault Diagnosis (FD) scheme for a real quadrotor Unmanned Aerial Vehicle (UAV) is proposed in this paper. Firstly, a novel Adaptive Thau observer (ATO) is developed to estimate the quadrotor system states and build a set of offset residuals to indicate actuators’ faults. Based on these residuals, some rules of Fault Diagnosis (FD) are designed to detect and isolate the faults as well as estimate the fault offset parameters. Secondly, a synthetic robust optimization scheme is presented to improve Fault Estimation (FE) accuracies, three key issues include modeling uncertainties, and magnitude order unbalances as well as noises are addressed. Finally, a typical fault of rotors is simulated and injected into one of four rotors of the quadrotor, and experiments for the FD scheme have been carried out. Unlike former research works on the FD schemes for quadrotors, our proposed FD scheme based on the ATO can not only detect and isolate the failed actuators, but also estimate the fault severities. Regardless of roughness of the real flying data, the FD results still have sufficient FE accuracies.     

基于自适应观测器的一类非线性系统鲁棒故障诊断

针对一类含有不确定性的非线性系统,对于执行器故障情形,提出了一种新的鲁棒故障诊断方法.首先设计了自适应观测器结构,并利用最小二乘法给出了故障估计递推算法.对系统中的不确定性,算法中采用域值处理技术以实现鲁棒故障估计.在此基础上,分析了该方法的鲁棒性,可检测性和稳定性.最后,给出了仿真实例,结果证明了该方法的有效性．     

An Impedance Force Control Approach to a Quad-Rotor System Based on an Acceleration-Based Disturbance Observer

This article presents the contact force control approach for a quad-rotor system to perform tasks of interacting with the environment. The hovering capability of the quad-rotor system allows the force in the altitude direction to be regulated by realizing the impedance function. To obtain the better force control performance, inherent and external disturbances to the quad-rotor system are suppressed by designing the acceleration-based disturbance observer (AbDOB). Force tracking impedance control is applied to regulate the contact force to the environment. Simulation studies of force tracking control for changing a light bulb on the ceiling are performed to evaluate the feasibility of the proposed force control task for a quad-rotor system.     

An Observer and Post Filter Based Scheme for Fault Estimation of Nonlinear Systems

International Journal of Control, Automation and Systems - The problem of actuator fault estimation for a kind of nonlinear discrete time varying (NDTV) systems is investigated. Norm bounded...     

Stabilization and Trajectory Tracking of a Quad-Rotor Using Vision

We propose a vision-based position control method, with the purpose of providing some level of autonomy to a quad-rotor unmanned aerial vehicle. Our approach estimates the helicopter X-Y-Z position with respect to a landing pad on the ground. This technique allows us to measure the position variables that are difficult to compute when using conventional navigation systems, for example inertial sensors or Global Positioning Systems in urban environment or indoor. We also present a method to measure translational speed in a local frame. The control strategy implemented is based on a full state feedback controller. Experimental results validate the effectiveness of our method.     

基于降维观测器的非最小相位系统的快速故障估计

针对传统的基于自适应观测器的故障诊断方法不适用于非最小相位系统的问题,本文基于降维 观测器提出了一种新的自适应故障估计方法．首先引入特殊坐标基（special coordinate basis, SCB）变换,可以 方便地求出误差系统的不变零点．其次对于变换之后的系统,基于降维观测器提出了一种新的快速故障估计 方法,目的在于提高故障估计的性能,即故障估计的快速性和准确性．最后仿真验证了此方法的有效性．     

基于未知输入观测器的直流电机鲁棒故障估计

针对直流电机系统提出一种基于未知输入观测器(UIO)的鲁棒故障估计方法,同时估计系统中的执行器故障和传感器故障。首先,构建包含系统传感器故障的增广状态系统;然后,基于该增广系统提出一种新颖的UIO,并给出了该观测器的存在条件和多故障估计策略;同时,引入H_∞性能指标最大程度地抑制干扰对故障估计结果的影响;接着,给出观测器的设计条件和参数求解过程并将其转化为易于求解的线性矩阵不等式(LMI)的形式;最后,通过算例仿真和实验验证了该方法的有效性和可用性。     

Robust Sliding Mode Observer based Fault Estimation for Certain Class of Uncertain Nonlinear Systems

This paper proposes a new scheme for estimating the actuator and sensor fault for Lipschitz nonlinear systems with unstructured uncertainties using the sliding mode observer (SMO) technique. Initially, a coordinate transformation is introduced to transform the original state vector into two parts such that the actuator faults only appear in the dynamics of the second state vector. The concept of equivalent output error injection is then employed to estimate the actuator fault. The effects of system uncertainties on the estimation errors of states and faults are minimized by integrating an uncertainty attenuation level into the observer. The sufficient conditions for the state estimation error to be bounded and satisfy a prescribed performance are derived and expressed as a linear matrix inequality (LMI) optimization problem. Furthermore, the proposed actuator fault estimation method is extended to sensor fault estimation. Finally, the effectiveness of the proposed scheme in estimating actuator and sensor faults has been illustrated considering an example of a single‐link flexible joint robot system.     

互补滤波算法在四旋翼飞行器姿态解算中的应用

针对四旋翼飞行器飞行过程中的姿态最优估计问题,本着准确、快速的原则,选择了基于陀螺仪、加速度计和电子罗盘的捷联式惯性测量系统.由于这些传感器存在温度漂移和噪声干扰等问题,采用互补滤波算法,通过融合IMU多传感器的数据信号,对测得的姿态数据进行补偿修正,解算出高精度的姿态角.为了验证互补滤波算法的有效性和实用性,通过实际的四旋翼飞行器角度测量系统对互补滤波算法展开研究.结果表明姿态角解算中采用互补滤波算法能够快速、稳定的输出高精度姿态数据,姿态角最大跟踪误差控制在±2°以内,满足四旋翼飞行器飞行控制的要求,成功完成了姿态的最优估计.     

Fault-tolerant Consensus of Leader-following Multi-agent Systems Based on Distributed Fault Estimation Observer

International Journal of Control, Automation and Systems - This paper is concerned with the fault-tolerant consensus control problem for leader-following multi-agent systems with actuator faults...     

基于混合滤波的四轴飞行器的姿态解算

针对四轴飞行器的姿态解算出现的姿态角数据漂移问题,提出一种基于Mahony滤波和互补滤波相结合的混合滤波算法,将传感器采集到的加速度、角速度以及磁场强度数据进行融合,利用加速度计和磁力计的向量偏差来对姿态解算过程中陀螺仪产生的积分累计误差进行修正.最后,建立姿态解算测试平台对混合滤波算法进行实验验证.实验结果表明,采用混合滤波算法的一次迭代滤波所需的平均用时为3.826 ms,比其他算法的平均用时短,混合滤波能有效地修正陀螺仪的积分累计误差,在降低运算复杂度的同时提高姿态解算的精度.     

Estimation of Edge Parameters and Image Blur Using Polynomial Transforms

A method is presented for detecting blurred edges in images and for estimating the following edge parameters: position, orientation, amplitude, mean value, and edge slope. The method is based on a local image decomposition technique called a polynomial transform. The information that is made explicit by the polynomial transform is well suited to detect image features, such as edges, and to estimate feature parameters. By using the relationship between the polynomial coefficients of a blurred feature and those of the a priori assumed (unblurred) feature in the scene, the parameters of the blurred feature can be estimated. The performance of the proposed edge parameter estimation method in the presence of image noise has been analyzed. An algorithm is presented for estimating the spread of a position-invariant Gaussian blurring kernel, using estimates at different edge locations over the image. First a single-scale algorithm is developed in which one polynomial transform is used. A critical parameter of the single-scale algorithm is the window size, which has to be chosen a priori. Since the reliability of the estimate for the spread of the blurring kernel depends on the ratio of this spread to the window size, it is difficult to choose a window of appropriate size a priori. The problem is overcome by a multiscale blur estimation algorithm where several polynomial transforms at different scales are applied, and the appropriate scale for analysis is chosen a posteriori. By applying the blur estimation algorithm to natural and synthetic images with different amounts of blur and noise, it is shown that the algorithm gives reliable estimates for the spread of the blurring kernel even at low signal-to-noise ratios.     

Estimation of Sinusoidal Frequencies and Amplitudes Using Adaptive Identifier and Observer

A simple method is proposed for estimation of amplitudes of multiple sinusoids. The estimation is based on the existing adaptive identifier which offers the globally convergent estimate of sinusoidal frequencies. To deal with possible singularities of the amplitude estimation, adaptive observers are also proposed for estimation of sinusoidal amplitudes. Simulations illustrate the results     

Polynomial Fuzzy Observer Designs: A Sum-of-Squares Approach

This paper presents a sum-of-squares (SOS) approach to polynomial fuzzy observer designs for three classes of polynomial fuzzy systems. The proposed SOS-based framework provides a number of innovations and improvements over the existing linear matrix inequality (LMI)-based approaches to Takagi-Sugeno (T-S) fuzzy controller and observer designs. First, we briefly summarize previous results with respect to a polynomial fuzzy system that is a more general representation of the well-known T-S fuzzy system. Next, we propose polynomial fuzzy observers to estimate states in three classes of polynomial fuzzy systems and derive SOS conditions to design polynomial fuzzy controllers and observers. A remarkable feature of the SOS design conditions for the first two classes (Classes I and II) is that they realize the so-called separation principle, i.e., the polynomial fuzzy controller and observer for each class can be separately designed without lack of guaranteeing the stability of the overall control system in addition to converging state-estimation error (via the observer) to zero. Although, for the last class (Class III), the separation principle does not hold, we propose an algorithm to design polynomial fuzzy controller and observer satisfying the stability of the overall control system in addition to converging state-estimation error (via the observer) to zero. All the design conditions in the proposed approach can be represented in terms of SOS and are symbolically and numerically solved via the recently developed SOSTOOLS and a semidefinite-program solver, respectively. To illustrate the validity and applicability of the proposed approach, three design examples are provided. The examples demonstrate the advantages of the SOS-based approaches for the existing LMI approaches to T-S fuzzy observer designs.     

基于观测器的LPV系统故障检测方法

针对一类线性参数变化(LPV)连续系统的故障检测问题,通过构造合适的输出观测器,获得残差生成器,并通过优化设计步骤,实现对干扰的有效抑制和对故障的灵敏检测。利用依赖参数的Lyapunov函数,在保证残差生成器稳定性的基础上,给出观测器存在的充分条件。应用投影定理,借助附加矩阵解除了基于参数的Lyapunov函数矩阵与系统矩阵的耦合,得到以线性矩阵不等式(LMI)形式表示的求解条件。对于参数变化系统,基于LMI的求解条件为无穷维问题,借助基函数和参数网格化方法,使其转变为可求解的问题。仿真结果表明,应用该方法可以在一定程度上抑制干扰,并能灵敏有效地实现故障检测。