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Exact Computation of Delay Margin by PID control: It Suffices to Solve a Unimodal Problem!

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Exact Computation of Delay Margin by PID Control: It Suffice...

第三十八届中国控制会议

作者： Jianqi Chen Dan Ma Yong Xu Jie Chen Department of Electronic Engineering City University of Hong Kong College of Information Science and Engineering State Key Laboratory of Synthetical Automation for Process Industries Northeastern University The School of Automation Guangdong Provincial Key Laboratory of Intelligent Decision and Cooperative Control Guangdong University of Technology

In this paper we study delay robustness of PID controllers in stabilizing systems containing uncertain, variable *** consider second-order unstable systems and seek analytical characterization and exact computation of the PID delay margin,where by PID delay margin we mean the maximal range of delay values within which the system can be robustly stabilized by a PID controller. Our contribution is threefold. First, we show that the delay margin achieved by PID control coincides with that by PD controllers. Second, we show that other than helping stabilize the delay-free part of a plant, the proportional control contributes no action to increase the delay margin. Finally, we show that the PID delay margin can be computed efficiently by solving a unimodal problem, that is, a univariate optimization problem that admits a unique maximum and hence is a convex optimization problem in one variable. This unimodal problem is one of pseudo-concave optimization and hence can be solved using standard convex optimization or gradient-based methods. As such, from a computational perspective, the PID delay margin problem is completely resolved in this paper! The results not only insure that the PID delay margin problem be readily solvable, but also provide fundamental conceptual insights into the PID control of delay systems, and analytical justifications to long-held engineering intuitions and heuristics, thus lending useful guidelines in the tuning and analytical design of PID controllers.

关键词： Delay margin robust stabilization PID controller uncertain time delay nonlinear programming pseudo-concavity

Notice of Retraction: Adaptive Decentralized Tracking control for Nonlinear Large-Scale Systems

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International Journal of Uncertainty, Fuzziness and Knowledge-Based Systems 2021年第5期29卷 789-789页

作者： Karthik Chandran Weidong Zhang Rajalakshmi Murugesan S. Prasanna A. Baseera Sanjeevi Pandiyan Department of Automation Shanghai Jiao Tong University Shanghai China Department of Mechatronics Jyothi Engineering College Thrissur India Department of EEE Ultra College of Engineering and Technology India School of Information Technology and Engineering VIT Vellore India School of Computing Science and Engineering VIT Bhopal University India Key Laboratory of Advanced Process Control for Light Industry Ministry of Education Jiangnan University Wuxi 214122 China

This article has been retracted at the request of the first and corresponding author, Dr. Karthik Chandran. The author has alerted the Editor-in-Chief of IJUFKS the reasons for the retraction: The proposed system was modelled with the incorrect data set. The system response has become incorrect because of this incorrect data set. Two percent of the information (mathematical assumptions) was taken from one paper without proper citation of the source.

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Numerical detection of Gaussian entanglement and its application to the identification of bound entangled Gaussian states

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arXiv 2020年

作者： Ma, Shan Xue, Shibei Guo, Yu Shu, Chuan-Cun School of Automation Central South University Changsha410083 China Peng Cheng Laboratory Shenzhen518000 China Department of Automation Shanghai Jiao Tong University Shanghai200240 China Key Laboratory of System Control and Information Processing Ministry of Education of China Shanghai200240 China Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering School of Physics and Electronic Science Changsha University of Science and Technology Changsha410114 China Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics and Electronics Central South University Changsha410083 China

We present a numerical method for solving the separability problem of Gaussian quantum states in continuous-variable quantum systems. We show that the separability problem can be cast as an equivalent problem of determining the feasibility of a set of linear matrix inequalities. Thus, it can be efficiently solved using existent numerical solvers. We apply this method to the identification of bound entangled Gaussian states. We show that the proposed method can be used to identify bound entangled Gaussian states that could be simple enough to be producible in quantum optics. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum optics

Secure analysis of dynamic networks under pinning attacks against synchronization

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arXiv 2019年

作者： Li, Yuzhe Shi, Dawei Chen, Tongwen State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110004 State Key Laboratory of Intelligent Control and Decision of Complex Systems School of Automation Beijing Institute of Technology Beijing100081 China Department of Electrical and Computer Engineering University of Alberta EdmontonABT6G 1H9 Canada

In this paper, we first consider a pinning node selection and control gain co-design problem for complex networks. A necessary and sufficient condition for the synchronization of the pinning controlled networks at a homogeneous state is provided. A quantitative model is built to describe the pinning costs and to formulate the pinning node selection and control gain design problem for different scenarios into the corresponding optimization problems. Algorithms to solve these problems efficiently are presented. Based on the developed results, we take the existence of a malicious attacker into consideration and a resource allocation model for the defender and the malicious attacker is described. We set up a leader-follower Stackelberg game framework to study the behaviour of both sides and the equilibrium of this security game is investigated. Numerical examples and simulations are presented to demonstrate the main results. Copyright © 2019, The Authors. All rights reserved.

关键词： Complex networks

Challenges and solutions in automotive powertrain systems

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Journal of control and Decision 2018年第1期5卷 61-93页

作者： Tielong Shen Mingxin Kang Jinwu Gao Jiangyan Zhang Yuhu Wu Department of Engineering and Applied Sciences Sophia UniversityTokyoJapan State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyangP.R.China State Key Laboratory of Automobile Simulation and Control Jilin UniversityChangchunP.R.China College of Mechanical and Electronic Engineering Dalian Minzu UniversityDalianP.R.China School of Control Science and Engineering Dalian University of TechnologyDalianP.R.China

Automotive powertrain mainly consisting of combustion engine,motor and battery(*** for hybrid powertrain)is a very complicated integration system,and the research on the automotive powertrain control techniques remains hot-spot in past *** paper proposes some challenging issues and control solutions of automotive powertrain system from the perspective of the dynamic system *** typical characteristics of automotive powertrain system are analysed for control development,and the several control applications using model-based and model-free control design are demonstrated with sufficient experimental *** addition,some open issues for future powertrain control development are summarised.

关键词： Model-based control model-free control combustion engine automotive powertrain control technology

Exponential convergence for distributed smooth optimization under the restricted secant inequality condition

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arXiv 2019年

作者： Yi, Xinlei Zhang, Shengjun Yang, Tao Johansson, Karl H. Chai, Tianyou Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden Department of Electrical Engineering University of North Texas DentonTX76203 United States State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

This paper considers the distributed smooth optimization problem in which the objective is to minimize a global cost function formed by a sum of local smooth cost functions, by using local information exchange. The standard assumption for proving exponential/linear convergence of first-order methods is the strong convexity of the cost functions, which does not hold for many practical applications. In this paper, we first show that the continuous-time distributed primal-dual gradient algorithm converges to one global minimizer exponentially under the assumption that the global cost function satisfies the restricted secant inequality condition. This condition is weaker than the strong convexity condition since it does not require convexity and the global minimizers are not necessary to be unique. We then show that the discrete-time distributed primal-dual algorithm constructed by using the Euler's approximation method converges to one global minimizer linearly under the same condition. The theoretical results are illustrated by numerical simulations. Copyright © 2019, The Authors. All rights reserved.

关键词： Continuous time systems

Linear convergence of first- And zeroth-order primal-dual algorithms for distributed nonconvex optimization

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arXiv 2019年

作者： Yi, Xinlei Zhang, Shengjun Yang, Tao Chai, Tianyou Johansson, Karl H. Division of Decision and Control Systems School of Electrical Engineering and Computer Science Kth Royal Institute of Technology Digital Futures Stockholm100 44 Sweden Department of Electrical Engineering University of North Texas DentonTX76203 United States State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

This paper considers the distributed nonconvex optimization problem of minimizing a global cost function formed by a sum of local cost functions by using local information *** first propose a distributed first-order primal-dual algorithm. We show that it converges sublinearly to a stationary point if each local cost function is smooth and linearly to a global optimum under an additional condition that the global cost function satisfies the Polyak-Lojasiewicz condition. This condition is weaker than strong convexity, which is a standard condition for proving linear convergence of distributed optimization algorithms, and the global minimizer is not necessarily unique. Motivated by the situations where the gradients are unavailable, we then propose a distributed zeroth-order algorithm, derived from the proposed distributed first-order algorithm by using a deterministic gradient estimator, and show that it has the same convergence properties as the proposed first-order algorithm under the same conditions. The theoretical results are illustrated by numerical simulations. Copyright © 2019, The Authors. All rights reserved.

关键词： Cost functions

A rigorous model for evaluating moving window soft sensors for industrial distillation processes

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Chemical Engineering Transactions 2018年 69卷 487-492页

作者： Torgashov, Andrei Skogestad, Sigurd An, Dmitry Process Control Laboratory Institute of Automation and Control Process FEB RAS 5 Radio Str. Vladivostok Russia Department of Chemical Engineering Norwegian University of Science and Technology TrondheimNO-7491 Norway Gazpromneft-Omsk Refinery JSC 1 Pr. Gubkina Omsk644040 Russia

ISBN: (纸本)9788895608662

Traditionally, soft sensors are developed based on measurement data only, but here we consider a moving window (MW) soft sensor (SS) that uses data generated from a calibrated, rigorous model of the distillation columns of an FFC unit at Gazpromneft-Omsk Refinery. The contribution of the paper is that a procedure is developed for MW SS design that incorporates a priori knowledge, which is especially suitable when the training sample is small and contains measurement errors. In addition, we propose a continuous adaptation of all model parameters based on new data, instead of the usual procedure of only updating the bias. The accuracy of the predicted product quality is investigated by calculating the coefficient of determination (R2) and root mean squared error (RMSE) for the test sample. Several approaches were considered, and we found that a constrained optimization approach was superior. The constraints on the model parameters of SSs are derived from a calibrated, rigorous distillation unit model. The improved estimator quality resulted in the successful industrial application of advanced process control (APC) systems. © Copyright 2018, AIDIC Servizi S.r.l.

关键词： Distillation columns

Practical PID Hovering control of a Laboratory Quadcopter Using Low-Cost Embedded control Hardware and Software

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Practical PID Hovering Control of a Laboratory Quadcopter Us...

UKACC International Conference on control (control)

作者： Dimitrios Iosifidis Nikolaos Alvanos Christos Yfoulis Simira Papadopoulou C. Galatsopoulos Department of Automation Engineering (DAE) ATEl of Thessaloniki GREECE Department of Automation Engineering ATEI of Thessaloniki GREECE DAE/ATEI of Thessaloniki GREECE Process Control in DAE/A.T.E.I. of Thessaloniki Chemical Process Engineering Research Institute Centre for Research and Technology Thermi Thessaloniki Greece

This paper presents an experimental setup developed mainly in the thesis work of a team of undergraduate students, who designed, built and controlled successfully a laboratory quadcopter. This project focused on the hovering control of a custom-built quadcopter with limited movement along a single vertical post, hence allowing safe operation in a typical laboratory environment, while leaving enough degrees of freedom for useful experimentation with practical PID control laws, which are often disregarded in the educational curriculum of a typical undergraduate control laboratory. The total cost of developing this equipment has been kept particularly low due to the adoption of a modern popular low-cost hardware and software Arduino-based platform and compatible sensors. Interesting future extensions concerning the possibilities offered by this new equipment for teaching, demonstration, project work, as well as research purposes, in the current laboratory practice, are also unfolded.

关键词： Brushless DC motors Permanent magnet motors Pulse width modulation Synchronous motors PI control