Article
Engineering, Electrical & Electronic
Daniel Gerbet, Klaus Roebenack
Summary: This article discusses the construction of high-gain observers for autonomous polynomial dynamical systems. Unlike the usual approach, the system's state is embedded into a higher dimensional Euclidean space. The observer state will be contained in this Euclidean space, which has a higher dimension than the system's state space. By using this embedding, singularities in the observation matrix can be avoided and global observers can be constructed in a structured way for some systems, which would not be possible in lower-dimensional cases. Finally, the state estimate in the original coordinates can be obtained through a projection. The proposed method is demonstrated on several example systems.
Article
Automation & Control Systems
Yuezu Lv, Zhongkui Li, Zhisheng Duan
Summary: This paper presents a framework on minimal-order specified-time unknown input observers for linear systems based on a pairwise observer structure. It first proposes a minimal-order specified-time observer for the linear system without the unknown input that can exactly estimate the state at the preset time. Another form of the specified-time observer is designed to further reduce the computational burden. In the presence of the unknown input, a minimal-order specified-time unknown input observer is presented by introducing a singular transformation to decouple the effect of the unknown input, with strong observability as the sufficient and necessary condition. The robustness of the proposed observers is also discussed.
Article
Automation & Control Systems
Zhe Zhang, Yunxia Song, Huaiyuan Jiang, Xuefei Yang
Summary: A family of observer-based periodic delayed feedback (PDF) controllers are proposed in this paper for the fixed-time stabilization of the linear input-delay system with immeasurable states. The relationship between the control gain and the system matrix is established by periodically switching the controller gain. Two different observer-predictor-based PDF controllers are proposed to address the open-loop problem faced by the standard PDF controller. Both controllers ensure that the closed-loop system converges asymptotically throughout the control period. Furthermore, a modified PDF is proposed for multi-input-multi-output systems utilizing the characteristic of controllability index set and observability index set.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2023)
Article
Automation & Control Systems
Sakthivel Rathinasamy, Aravinth Narayanan, Ohmin Kwon
Summary: This study focuses on the state tracking problem of periodic piecewise polynomial systems subject to multiple disturbances and actuator faults. It proposes a method of approximating the system dynamics over each period using Bernstein polynomials and designs a disturbance observer to estimate the disturbance caused by an exogenous system. By considering time-varying polynomial Lyapunov function and linear matrix inequalities, a set of sufficient conditions for control is derived. MATLAB software is used to compute the desired controller and observer gain matrices. A numerical example with simulation results is provided to confirm the potential and significance of the theoretical findings.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2022)
Article
Automation & Control Systems
Li Li, Yaofeng Zhang, Yonglong Liao
Summary: This article presents a designing method for observer-based feedback preview control and static output feedback preview control for linear uncertain discrete-time periodic systems. The approach involves employing a difference operator and state augmentation technique to derive an augmented error system, designing a state observer and preview controller for signal tracking performance, and obtaining sufficient conditions for closed-loop systems using Lyapunov stability theory. Two numerical simulation examples are provided to demonstrate the effectiveness of the proposed method.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2021)
Article
Automation & Control Systems
R. Sakthivel, N. Aravinth, T. Satheesh, O. M. Kwon
Summary: This paper addresses the input-output finite-time stabilisation problem for a class of continuous-time periodic piecewise polynomial systems with immeasurable states and external disturbances. A state estimation-based robust reliable controller is proposed to solve this problem, and a periodic piecewise polynomial observer is designed to estimate the immeasurable states. The stability conditions are obtained by combining Lyapunov stability theory, linear matrix inequality technique and IO-FT stability theory. Simulation results demonstrate the effectiveness and utility of the proposed control protocol.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2023)
Article
Mathematics, Interdisciplinary Applications
N. Aravinth, R. Sakthivel, T. Satheesh, M. Chadli
Summary: This investigation proposes a robust tracking control method for periodic piecewise polynomial systems using a proportional integral observer (PIO) and parallel equivalent input disturbance (PEID) approach. It effectively suppresses parameter uncertainties, time delays, and external disturbances.
CHAOS SOLITONS & FRACTALS
(2023)
Article
Computer Science, Information Systems
Chenchen Fan, James Lam, Xiaochen Xie, Xiaoqi Song
Summary: This paper addresses the output reachable set synthesis problem for periodic piecewise time-varying systems for the first time, developing sufficient conditions for periodic time-varying observer and controller with reduced conservatism. An iterative algorithm is proposed to obtain the periodic time-varying observer and controller gains, and a numerical example is presented to illustrate the validity of the proposed methods.
INFORMATION SCIENCES
(2021)
Article
Engineering, Multidisciplinary
Yifan Xu, Xueyun Wang, Jingjuan Zhang
Summary: An accurate aircraft dynamic model is crucial for the design of flight control system and analysis of flight characteristics for tiltrotor UAV. The traditional test-bed identification method is insufficient to simulate real flying conditions, hence a real-time method based on Error-State Kalman Filter is proposed to estimate the model parameters. Observability analysis is conducted to ensure convergence of the proposed method, and both simulations and real flight experiments demonstrate the effectiveness of the method.
Article
Automation & Control Systems
Yanfang Lei, Junmin Li
Summary: This paper focuses on stabilizing parabolic systems with time-varying delay, external disturbance, and nonlinear periodic time-varying parameter (NPTVP). A neural networks (NNs) approximator is designed using Fourier series expansion (FSE) method and NNs approximation technology to describe the uncertain dynamic term with NPTVP. Two robust adaptive neural network control (RANNC) algorithms are then designed based on adaptive control theory, NNs approximation technology, and reparameterization method to achieve asymptotic stability and prescribed adaptive H-infinity performance of disturbance attenuation. Sufficient conditions for the stability and performance requirements of the resulting closed-loop systems are derived, and simulations are carried out to verify the effectiveness of the proposed RANNC algorithms.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2022)
Article
Automation & Control Systems
N. Aravinth, R. Sakthivel, T. Satheesh, O. M. Kwon, S. Harshavarthini
Summary: This article investigates the resilient tracking control problem for periodic piecewise polynomial systems with time delay and disturbances using the proportional integral observer (PIO). The system is divided into subintervals defined by matrix polynomial functions, and the PIO strategy is employed to estimate the states with high precision. A PIO-based tracking control is configured with gain perturbations and $ H_\infty $ performance is employed to attenuate the effects of disturbances. The time-varying polynomial Lyapunov-Krasovskii functional is used to establish conditions in the form of linear matrix inequalities, and the time-varying gain matrices are computed using MATLAB. A numerical example is provided to demonstrate the potential and usefulness of the proposed method.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2023)
Article
Automation & Control Systems
Hamdi Gassara, Mohamed Boukattaya, Ahmed El Hajjaji
Summary: This paper investigates the delay-dependent state, Fault Estimation (FE), and Fault Tolerant Control problems for polynomial fuzzy systems with time delay. A polynomial adaptive fuzzy observer is utilized to estimate system states and actuator faults. A polynomial Lyapunov-Krasovskii functional with a double integral term is introduced to obtain delay-dependent sufficient conditions, which can be solved via SOSTOOLS and a Semi-Definite Program solver. By utilizing the FE information, a polynomial fuzzy fault tolerant controller is designed to ensure system stability and compensate for the impact of actuator faults. Several examples are provided to illustrate the applicability of the delay-dependent results presented in this paper.
INTERNATIONAL JOURNAL OF FUZZY SYSTEMS
(2023)
Article
Automation & Control Systems
Chaoqun Dai, Yuqian Guo
Summary: This study proposes a novel technique, called the subset transition method, for finite-time controllability and stabilization of probabilistic logical dynamic control systems (PLDCS) with a state-dependent control constraint. The main idea is to construct an unconstrained deterministic logical control system, called the subset transition system (SubSTS), characterizing the transitional dynamics between subsets under common admissible controls. Necessary and sufficient conditions for set controllability and set stabilizability are obtained based on the SubSTS. Examples are presented to demonstrate the application of the obtained results.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2023)
Article
Engineering, Multidisciplinary
Kai Yang, Shaoyu Dou, Pan Luo, Xin Wang, H. Vincent Poor
Summary: This paper introduces a sequence to Gaussian Mixture Model (seq2GMM) framework, aiming to identify anomalous and interesting time series within a network time series database. By developing a surrogate-based optimization algorithm, the model exhibits strong performance on multiple public benchmark datasets, outperforming state-of-the-art anomaly detection techniques.
IEEE TRANSACTIONS ON NETWORK SCIENCE AND ENGINEERING
(2022)
Article
Automation & Control Systems
Daniel Gerbet, Klaus Roebenack
Summary: Observers are used in control applications to estimate system state, parameters, or detect faults. Systematic observer design is based on observer or observability normal form. The former is preferred for easier design, but is applicable to a smaller subset of dynamical systems compared to the latter. Nonlinear systems may have singularities or fail Lipschitz condition in the observability normal form, which can be avoided by embedding the system in a higher-dimensional state space. This paper discusses this embedding and its implications for polynomial multiple input or output systems.
AT-AUTOMATISIERUNGSTECHNIK
(2023)
