Article
Automation & Control Systems
Sei Zhen Khong
Summary: This article presents necessary and sufficient conditions for robust stability of a feedback interconnection of linear time-invariant systems. It is shown that the feedback interconnection is stable when the instantaneous gain of the loop transfer function is zero and the static loop gain is less than unity.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Mohamed Mabrok, Mahmoud Abdelrahim
Summary: This paper presents a methodology to find the nearest negative imaginary system and employs the result to construct a near optimal linear quadratic Gaussian controller. The problem is formulated using port-Hamiltonian method and the required conditions are defined in terms of linear matrix inequalities. The technique is solved systematically using the fast gradient method.
IET CONTROL THEORY AND APPLICATIONS
(2023)
Article
Automation & Control Systems
Pravin Behera, Arnab Dey, Sourav Patra
Summary: This paper utilizes a dissipative framework to construct a set of stabilizing controllers in positive feedback for LTI negative imaginary (NI) systems with no pole at origin. The technique relies on identifying a dissipative characterization of such NI systems. Contrary to the existing literature, the set of controllers presented in this paper may not belong to the NI systems class and can be designed having only a rough estimate of the DC gain of the plant. Apart from extending the class of stabilizing controllers beyond the NI family, the proposed framework also generalizes a few existing NI domain results.
Article
Automation & Control Systems
Kanghong Shi, Ian R. Petersen, Igor G. Vladimirov
Summary: This article presents a protocol to solve the robust output feedback consensus problem for networked heterogeneous nonlinear NI systems with free body motion. The definition of nonlinear NI systems is extended to accommodate systems with free body dynamics. A new stability result and a class of networked nonlinear OSNI controllers are proposed to achieve output feedback consensus for heterogeneous networked nonlinear NI systems. The numerical example demonstrates the effectiveness of this control framework.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Bhawana Singh, Shyam Kamal, Sourav Patra, Sandip Ghosh
Summary: This paper introduces the application of rated convergence properties in the framework of nonlinear negative imaginary systems theory. New definitions of negative imaginary for general nonlinear systems are provided, and the relationship between these definitions and rated stability is investigated. Additionally, positive-feedback interconnections are discussed and a methodology of control for maintaining stability under positive feedback is developed. Theoretical results are validated through academic and real-world examples.
Article
Automation & Control Systems
Qin Xu, Liu Liu, Yufeng Lu
Summary: This paper addresses the converse problems related to the robust stability of finite dimensional negative imaginary systems and establishes various converse negative imaginary theorems for linear time-invariant systems. The research demonstrates that the feedback interconnection stability of a specific system with an arbitrary strictly negative imaginary system implies the negative imaginary property of the specific system.
INTERNATIONAL JOURNAL OF CONTROL
(2023)
Article
Engineering, Multidisciplinary
Mohamed A. Mabrok, Maryam Ahmed Alyami, Emad E. Mahmoud
Summary: This paper introduces a new concept of negative imaginary systems and proposes a new definition for extending nonlinear negative imaginary systems. Two different quadratic dynamic supply rates are introduced to broaden the applicability of the dissipativity concept. The new definition allows for a wider range of analysis on negative imaginary systems, enabling consideration of a greater variety of dynamical systems.
ALEXANDRIA ENGINEERING JOURNAL
(2021)
Article
Automation & Control Systems
Kanghong Shi, Ian R. Petersen, Igor G. Vladimirov
Summary: This paper proposes a state feedback stabilization approach for nonlinear systems with relative degree less than or equal to two by transforming them into nonlinear negative imaginary (NI) systems. The paper provides conditions under which a nonlinear system can be made a nonlinear NI system or a nonlinear output strictly negative imaginary (OSNI) system. It is shown that if an input-affine nonlinear system has a normal form with relative degree less than or equal to two after output transformation, it can be rendered nonlinear NI and nonlinear OSNI. Additionally, if the internal dynamics of the normal form are input-to-state stable, there exists a state feedback input that can stabilize the system. The paper also extends this stabilization result to systems with nonlinear NI uncertainty, and presents a numerical example to illustrate the process of stabilizing an uncertain system using the proposed approach.
Article
Automation & Control Systems
Parijat Bhowmick, Alexander Lanzon
Summary: This paper introduces static pre- and post-compensation schemes to transform non-square LTI systems into a subset of Negative Imaginary systems, and stabilize non-square or non-NI square systems in a positive feedback loop. It also presents a constant reference tracking scheme based on the integral controllability property of SSNI systems, and develops observer-based pre- and post-compensators for systems with unavailable state measurements. The compensation schemes are further extended to handle polytopic uncertainty in stable, non-square, or non-NI square systems.
Article
Automation & Control Systems
M. A. Mabrok
Summary: This paper presents a control synthesis methodology for negative imaginary (NI) systems based on nonlinear optimization techniques, creating a library of strictly negative imaginary (SNI) controllers and using sequential quadratic programming (SQP) techniques for optimization. The synthesized controller satisfies the SNI property while optimizing performance, demonstrated through an example of controlling a Euler-Bernoulli beam with piezoelectric actuator and sensor.
INTERNATIONAL JOURNAL OF CONTROL
(2021)
Article
Automation & Control Systems
Di Zhao, Chao Chen, Sei Zhen Khong
Summary: In this study, the theory of negative imaginary (NI) systems is extended to a nonlinear framework using a frequency-domain approach. The extended notion is characterized through finite-frequency integration over a kernel function and bounded input-output signal pairs. The feedback stability of the proposed nonlinear NI systems is established based on integral quadratic constraints.
Article
Automation & Control Systems
Alexander Lanzon, Parijat Bhowmick
Summary: In this article, we define the notion of stable input-output negative imaginary (IONI) systems. This new class captures and unifies all the existing stable sub-classes of negative imaginary (NI) systems and is capable of distinguishing between the strict subclasses in the literature. We also provide linear matrix inequality (LMI) tests on the state-space matrices to check whether a system belongs to the IONI class or any of its important subclasses. Additionally, the derived results are specialized for OSNI systems. Rating: 8/10
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Parijat Bhowmick, Arnab Dey
Summary: This paper presents a new approach for applying negative imaginary (NI) stability results to a wider range of systems. This approach no longer requires the existence of strictly negative imaginary (SNI) properties in the systems and can handle systems with purely imaginary poles. Additionally, this approach can cover existing stability results of NI systems.
IEEE CONTROL SYSTEMS LETTERS
(2022)
Article
Automation & Control Systems
Junyan Hu, Barry Lennox, Farshad Arvin
Summary: This paper proposes a consensus-based formation tracking scheme for multi-robot systems utilizing the Negative Imaginary (NI) theory. The proposed scheme applies to networked robotic systems that consist of single integrator agents with stable uncertainties connected via an undirected graph. It offers robustness to model uncertainties and fault-tolerance to a sudden loss of robots.
Article
Automation & Control Systems
Dingchao Ren, Junlin Xiong, Daniel W. C. Ho
Summary: This paper investigates the design of static output feedback (SOF) NI controllers with H-infinity performance and proposes an iterative LMI-based algorithm for synthesis.
Article
Automation & Control Systems
Alexander Lanzon, Parijat Bhowmick
Summary: In this article, we define the notion of stable input-output negative imaginary (IONI) systems. This new class captures and unifies all the existing stable sub-classes of negative imaginary (NI) systems and is capable of distinguishing between the strict subclasses in the literature. We also provide linear matrix inequality (LMI) tests on the state-space matrices to check whether a system belongs to the IONI class or any of its important subclasses. Additionally, the derived results are specialized for OSNI systems. Rating: 8/10
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Tao Yu, Junlin Xiong
Summary: This paper studies the decentralised H-infinity filtering problem for interconnected discrete-time systems. The developed decentralised filter scheme only uses local output information. The paper derives novel computationally attractive sufficient conditions without inversion terms to guarantee the H-infinity performance of the augmented system, and transforms these conditions into linear matrix inequalities through solving them.
INTERNATIONAL JOURNAL OF CONTROL
(2023)
Article
Automation & Control Systems
Dingchao Ren, Junlin Xiong, Daniel W. C. Ho
Summary: This paper studies the problem of designing a static output feedback H-2 negative imaginary controller. A linearisation-based method is proposed to overcome the difficulty of solving constraints, and an iterative algorithm is provided to compute the desired controller. The results are illustrated through numerical examples.
INTERNATIONAL JOURNAL OF CONTROL
(2023)
Article
Automation & Control Systems
Jing Lai, Junlin Xiong, Zhan Shu
Summary: This paper investigates the optimal control problem for a class of discrete-time stochastic systems subject to additive and multiplicative noises. An algebraic Riccati equation is established which gives the form of the solution to the problem. To obtain the optimal control gain iteratively, an offline policy iteration is presented with convergence proof. A model-free reinforcement learning algorithm is proposed to learn the optimal admissible control policy using the system states and inputs without resorting to the system matrices. It is proven that the estimation error of the kernel matrix is bounded and the iterative control gain is admissible. Compared with the existing work, this paper considers the model-free controller learning problem for stochastic systems suffering from both additive and multiplicative noises using reinforcement learning. The proposed algorithm is illustrated through a numerical example, which shows that our algorithm outperforms other policy iteration algorithms.
Article
Automation & Control Systems
Zhiying Wu, Zhe Wang, Yan Wang, Junlin Xiong, Min Xie
Summary: This paper investigates the dynamic event-triggered predictive control problem for discrete-time networked control systems under deception attacks. A new dynamic event-triggered scheme is proposed, and the Luenberger observer and networked predictive control method are used. Sufficient conditions are established to guarantee the stability of the closed-loop systems. The effectiveness of the approach is validated through experiments.
INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL
(2023)
Article
Automation & Control Systems
Lin Yu, Junlin Xiong, Min Xie
Summary: This article focuses on solving two-player zero-sum games without assuming the strict existence of saddle point. The upper and lower performance index functions are used to seek the solution of the games. The generalized policy iteration technique is applied to design the controller, and neural network approximators are used to update the approximation of the performance index functions. The convergence of the upper and lower performance index function sequences indicates the attainment of the saddle point.
JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS
(2023)
Article
Environmental Sciences
Xiangyang Dou, Xuanmei Fan, Xin Wang, Ali P. P. Yunus, Junlin Xiong, Ran Tang, Marco Lovati, Cees van Westen, Qiang Xu
Summary: As the Third Pole of the Earth and the Water Tower of Asia, the Tibetan Plateau (TP) plays a vital role in regional freshwater ecosystem. However, the increase in glacial lakes due to global climate change increases the risk of sudden glacial lake outbursts and consequent floods, posing severe threats to the valley population. This study created a high-resolution multi-temporal inventory of glacial lakes in TP using satellite images from 1990 to 2019, showing an overall increase in number and area of glacial lakes. This inventory provides valuable data for studying climate change-glacier-glacial lake-GLOF interactions and hydro-climatic studies.
Article
Automation & Control Systems
Subhransu S. Bhattacharjee, Ian R. Petersen
Summary: In this paper, a closed-loop optimization method called Whiplash inertial gradient dynamics is proposed, which utilizes gradient information. Symplectic asymptotic convergence analysis is introduced for the Whiplash system in convex functions. Relaxation sequences are also introduced to explain the nonclassical nature of the algorithm, along with a deterministic exploring heuristic variant of the Whiplash algorithm to escape saddle points. The authors provide practical methodology for analyzing convergence rates using integral constraint bounds and a novel Lyapunov rate method, demonstrating polynomial and exponential rates of convergence for quadratic costs.
ASIAN JOURNAL OF CONTROL
(2023)
Article
Automation & Control Systems
Di Deng, Junlin Xiong
Summary: This paper investigates the problem of stochastic event-triggered remote state estimation over a Gaussian communication channel. An approximate minimum mean squared error estimator with adaptive weights is derived based on a commonly-accepted Gaussian assumption. The proposed estimator combines the estimates for both transmission and no transmission cases and has comparable performance to those that know the triggering decisions.
Article
Automation & Control Systems
Xing Wang, Bo Li, Jr-Shin Li, Ian R. Petersen, Guodong Shi
Summary: This article presents graph theoretic conditions for the controllability and accessibility of bilinear systems over different groups in the presence of drift terms. The system's properties are related to two interaction graphs, one from the drift and another from the controlled dynamics, based on the classical Lie algebra rank condition. The article establishes a systematic way to transform the Lie bracket operations in the underlying Lie algebra into specific operations of removing or creating links over the drift and controlled interaction graphs, leading to a series of graphical conditions for the controllability and accessibility of such bilinear systems.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Di Deng, Junlin Xiong
Summary: This paper investigates the stochastic event-triggered remote state estimation problem over a collision channel. A Gaussian approximation method is used to prove that the posterior distribution of the system state is a mixture of two Gaussians and a mixture of three Gaussians in the cases of collision and successful transmission, respectively. An approximate minimum mean squared error estimator with adaptive weights is proposed, and the estimator is shown to have conventional forms under extreme situations. Numerical results illustrate the effectiveness of the proposed estimator based on incomplete information.
INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE
(2023)
Article
Automation & Control Systems
Hongsheng Qi, Biqiang Mu, Ian R. Petersen, Guodong Shi
Summary: In this article, we study the recursion corresponding to measurement outcomes for open quantum networks under sequential measurements. We show that the state transition of the induced Boolean network can be explicitly represented through a real version of the master equation. We also demonstrate that structural properties of the induced Boolean network are direct consequences of the relaxing property of open quantum dynamics.
IEEE TRANSACTIONS ON CONTROL OF NETWORK SYSTEMS
(2023)
Article
Automation & Control Systems
Valery Ugrinovskii, Ian R. Petersen, Iman Shames
Summary: Among first order optimization methods, Polyak's heavy ball method is known to achieve the same asymptotic rate of convergence as Nesterov's lower bound for functions in infinite-dimensional space. This paper demonstrates that the heavy ball method is provably worst-case asymptotically optimal when applied to quadratic functions in a finite dimensional space, using results on the robust gain margin of linear uncertain feedback control systems.
Article
Automation & Control Systems
Kanghong Shi, Ian R. Petersen, Igor G. Vladimirov
Summary: This article presents a protocol to solve the robust output feedback consensus problem for networked heterogeneous nonlinear NI systems with free body motion. The definition of nonlinear NI systems is extended to accommodate systems with free body dynamics. A new stability result and a class of networked nonlinear OSNI controllers are proposed to achieve output feedback consensus for heterogeneous networked nonlinear NI systems. The numerical example demonstrates the effectiveness of this control framework.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Article
Automation & Control Systems
Vu Phi Tran, Mohamed A. Mabrok, Sreenatha G. Anavatti, Matthew A. Garratt, Ian R. Petersen
Summary: This article introduces a novel robust adaptive control synthesis methodology for attitude and altitude stabilization of a quadrotor robot. The method combines fuzzy reinforcement learning and negative imaginary property to achieve better control performance.
IEEE TRANSACTIONS ON CYBERNETICS
(2023)
Article
Automation & Control Systems
Xiaoyu Luo, Chengcheng Zhao, Chongrong Fang, Jianping He
Summary: This paper investigates the problem of false data injection attacks in multi-agent dynamical systems and proposes FDI attack set selection algorithms to maximize the convergence error by finding the optimal subset of compromised agents.
Article
Automation & Control Systems
Nitin K. Singh, Abhisek K. Behera
Summary: In this paper, a twisting observer is proposed for robustly estimating the states of a second-order uncertain system. The observer approximates the unknown sign term for the non-measurable state with a delayed output-based switching function, and achieves the desired steady-state accuracy by controlling the delay parameter. The application of the observer to output feedback stabilization is also discussed.
Article
Automation & Control Systems
Alexander Aleksandrov
Summary: This paper investigates the absolute stability problem for positive Persidskii systems with delay, proposes a special construction method for diagonal Lyapunov-Krasovskii functionals, and derives a criterion for the existence of such functionals guaranteeing the absolute stability, as well as obtaining sufficient conditions for a family of time-delay Persidskii systems to construct a common diagonal Lyapunov-Krasovskii functional. The efficiency of the developed approaches is demonstrated through four examples.
Article
Automation & Control Systems
Noureddine Toumi, Roland Malhame, Jerome Le Ny
Summary: This paper addresses large multi-agent dynamic discrete choice problems using a linear quadratic mean field games framework. The model incorporates the features where agents have to reach a predefined set of possible destinations within a fixed time frame and running costs can become negative to simulate crowd avoidance. An upper bound on the time horizon is derived to prevent agents from escaping to infinity in finite time. The existence of a Nash equilibrium for infinite population and its epsilon-Nash property for a large but finite population are established. Simulations are conducted to explore the model behavior in various scenarios.
Article
Automation & Control Systems
Philippe Schuchert, Vaibhav Gupta, Alireza Karimi
Summary: This paper presents the design of fixed-structure controllers for the As2 and Asw synthesis problem using frequency response data. The minimization of the norm of the transfer function between the exogenous inputs and performance outputs is approximated through a convex optimization problem involving Linear Matrix Inequalities (LMIs). A general controller parametrization is used for continuous and discrete-time controllers with matrix transfer function or state-space representation. Numerical results show that the proposed data-driven method achieves performance equivalent to model-based approaches when a parametric model is available.
Correction
Automation & Control Systems
Zhijun Guo, Gang Chen
Article
Automation & Control Systems
Matteo Della Rossa, Thiago Alves Lima, Marc Jungers, Raphael M. Jungers
Summary: This paper presents new stabilizability conditions for switched linear systems with arbitrary and uncontrollable underlying switching signals. The study focuses on two specific settings: the robust case with completely unknown and unobservable active mode, and the mode-dependent case with controller depending on the current active switching mode. The technical developments are based on graph-theory tools and path-complete Lyapunov functions framework, enabling the design of robust and mode-dependent piecewise linear state-feedback controllers using directed and labeled graphs.
Article
Automation & Control Systems
Elena Petri, Romain Postoyan, Daniele Astolfi, Dragan Nesic, W. P. M. H. (Maurice) Heemels
Summary: This study investigates a scenario where a perturbed nonlinear system transmits its output measurements to a remote observer via a packet-based communication network. By designing both the observer and the local transmission policies, accurate state estimates can be obtained while only sporadically using the communication network.
Article
Automation & Control Systems
Jonas Krook, Robi Malik, Sahar Mohajerani, Martin Fabian
Summary: This paper proposes a method to synthesise controllers for cyber-physical systems subjected to disturbances, such that the controlled system satisfies specifications given as linear temporal logic formulas. The approach constructs a finite-state abstraction of the original system and synthesises a controller for the abstraction. It introduces the robust stutter bisimulation relation to account for disturbances and uncertainty, ensuring that related states have similar effects under the same controller. The paper demonstrates that the existence of a controller for the abstracted system implies the existence of a controller for the original system enforcing the linear temporal logic formula.
Article
Automation & Control Systems
Clement Chahbazian, Karim Dahia, Nicolas Merlinge, Benedicte Winter-Bonnet, Aurelien Blanc, Christian Musso
Summary: The paper derives a recursive formula of the Fisher information matrix on Lie groups and applies it to nonlinear Gaussian systems on Lie groups for testing. The proposed recursive CRLB is consistent with state-of-the-art filters and exhibits representative behavior in estimation errors. This paper provides a simple method to recursively compute the minimal variance of an estimator on matrix Lie groups, which is fundamental for implementing robust algorithms.
Article
Automation & Control Systems
Yiheng Fu, Pouria Ramazi
Summary: This study investigates the characteristics of decision fluctuations in heterogeneous populations and explores the uncertainties in imitation behavior. The findings are important for understanding the bounded rationality nature of imitation behaviors.
Article
Automation & Control Systems
Lars A. L. Janssen, Bart Besselink, Rob H. B. Fey, Nathan van de Wouw
Summary: This paper introduces a mathematical relationship between the accuracy of reduced-order linear-time invariant subsystem models and the stability and accuracy of the resulting reduced-order interconnected linear time-invariant model. This result can be used to directly translate the accuracy characteristics of the reduced-order subsystem models to the accuracy properties of the interconnected reduced-order model, or to translate accuracy requirements on the interconnected system model to accuracy requirements on subsystem models.
Article
Automation & Control Systems
Piyush Gupta, Vaibhav Srivastava
Summary: We study the optimal fidelity selection for a human operator servicing tasks in a queue, considering the trade-off between high-quality service and penalty due to increased queue length. By modeling the operator's cognitive dynamics and task fidelity, we determine the optimal policy and value function numerically, and analyze the structural properties of the optimal fidelity policy.
Article
Automation & Control Systems
Lukas Schwenkel, Alexander Hadorn, Matthias A. Mueller, Frank Allgoewer
Summary: In this work, the authors study economic model predictive control (MPC) in periodic operating conditions. They propose a method to achieve optimality by multiplying the stage cost by a linear discount factor, which is easy to implement and robust against online changes. Under certain assumptions, they prove that the resulting linearly discounted economic MPC achieves optimal asymptotic average performance and guarantees practical asymptotic stability of the optimal periodic orbit.
Article
Automation & Control Systems
Taher Ebrahim, Sankaranarayanan Subramanian, Sebastian Engell
Summary: We propose a robust nonlinear model predictive control algorithm for dynamic systems with mixed degrees of freedom. This algorithm optimizes both continuous and discrete manipulated variables, enhancing closed-loop performance. Our approach relies on a computationally efficient relaxation and integrality restoration strategy and provides sufficient conditions to establish recursive feasibility and guarantee robust closed-loop stability. The effectiveness of the approach is demonstrated through two nonlinear simulation examples.
