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12th International Conference on Optimization and Applications, OPTIMA 2021

作者： Gruzdeva, Tatiana V. Khamisov, Oleg V. Matrosov Institute for System Dynamics and Control Theory of SB RAS 134 Lermontov Street Irkutsk664033 Russia Melentiev Energy Systems Institute of SB RAS 130 Lermontov Street Irkutsk664033 Russia

ISBN: (纸本)9783030910587

We propose an approach to finding the roots of systems of quadratic equations in a box. This approach is based on a reduction to an auxiliary optimization problem. The auxiliary problem turns out to be, in general, a nonconvex optimization problem, with the objective function and inequality constraints given by d.c. functions. We use the linearization technique with respect to the basic nonconvexity and box partition procedure to try to find all solutions of the system or proof that there are no solutions in the box. The results of the computational simulation are given. © 2021, Springer Nature Switzerland AG.

关键词： Quadratic programming

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Iterative Learning control for Variable Pass Length systems

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IFAC Proceedings Volumes 2011年第1期44卷 4880-4885页

作者： Thomas Seel Thomas Schauer Jörg Raisch Control Systems Group Technische Universität Berlin Germany Systems and Control Theory Group Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany

Abstract Monotonic convergence of linear iterative learning control (ILC) systems with changing pass length is considered. The maximum pass length (MPL) error is introduced as a useful concept for convergence analysis of this class of systems. Using the lifted-system framework, a both necessary and sufficient monotonic convergence criterion is found for the 1-norm of the MPL error. Further findings on 2-norm and ∞-norm convergence are added. Finally, an example system is given, i.e. the control of an electrical stimulation system for gait assistance, and simulation results are provided.

关键词： iterative learning control variable pass length discrete-time linear systems lifted system framework convergence analysis monotonic convergence biomedical systems

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Planning a finite time transition from a non-stationary to a stationary point without overshoot

Planning a finite time transition from a non-stationary to a...

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2008 American control Conference (ACC), vol.12

作者： Johann Reger Systems and Control Theory Group Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany

The problem of planning a finite time transition of a trajectory from a non-stationary point to a stationary set-point is addressed. As opposed to standard approaches, where the transition functions are polynomials, the specific choice of non-analytic function proposed may easily be trimmed to show no overshoot and only an adjustable undershoot during transition. The main result is a recursive formula for a simple parametrization of the transition function, as needed in tracking problems. Two examples underscore the ease of the approach.

关键词： Polynomials Trajectory Boundary conditions Proposals control systems

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Iterative learning control of drop foot stimulation with array electrodes for selective muscle activation

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IFAC Proceedings Volumes 2014年第3期47卷 6587-6592页

作者： M. Valtin T. Seel J. Raisch T. Schauer Control Systems Group Technische Universität Berlin Berlin Germany Systems and Control Theory Group Max Planck Institute for Dynamics of Complex Technical Systems Magdeburg Germany

Disorders of the central nervous system like stroke often lead to a paresis of the muscles responsible for dorsiflexion and eversion of the foot during swing phase. Functional electrical stimulation (FES) is commonly used to improve the foot movement. A precise placement of two single surface electrodes on the shank as well as a manual tuning of heel-switch triggered stimulation is required when using standard drop-foot stimulators. In this work, the use of automatically tuned array electrodes for selective nerve/muscle stimulation and the application of iterative learning control for adjusting stimulation intensities are investigated with the aim to obtain an optimal foot movement. The stimulation effect is observed by means of two inertial measurement units mounted on the foot and shank, respectively. Two array electrodes are placed over the areas covering the peroneal nerve and the muscle tibialis anterior. A fast identification procedure finds three suitable sets of array elements, forming so-called virtual electrodes, in both arrays. Two stimulation channels are established over the three virtual electrodes. Both channels produce dorsiflexion, but one promotes eversion and the other inversion. A decoupling matrix is applied to the stimulation intensities of both channels in order to obtain independent control over dorsiflexion and eversion. Finally, two independent iterative learning controllers are employed to achieve desired angle profiles. The proposed stimulation and control scheme is initially tested on a healthy person sitting on a table with the shank and foot free to swing. A tracking RMS error of less than one degree is achieved within six walking steps.

关键词： Iterative Learning control Biomedical System Array Electrodes MIMO Decoupling Virtual Electrodes Functional Electrical Stimulation

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Hybrid-data-driven fuzzy recognition of operator cognitive state in human-machine cooperative control system

Hybrid-data-driven fuzzy recognition of operator cognitive s...

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13th IFAC Symposium on Large Scale Complex systems: theory and Applications, LSS 2013

作者： Zhang, Jian-Hua Raisch, Jörg Dept. of Automation East China University of Science and Technology Shanghai 200237 China Control Systems Group Technische Universität Berlin D-10587 Berlin Germany Systems and Control Theory Group Max Planck Institute for Dynamics of Complex Technical Systems D-39106 Magdeburg Germany

In this paper, the Human Cognitive State (HCS) in the context of human and complex system interaction was classified by using the Fuzzy C-Means (FCM) algorithm. The most important features for the HCS pattern classification were extracted from a set of measured physiological variables based on the comparison of their respective rates of correct classification. The results have shown the usefulness of the FCM algorithm as well as the selected features for the challenging HCS classification problem. © IFAC.

关键词： Fuzzy set theory

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On the optimal design of linear networked systems

On the optimal design of linear networked systems

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作者： Azhmyakov, V. Galvan-Guerra, R. Velazquez Cuevas, R. Poznyak, A.S. Departamento de Control Automatico CINVESTAV A.P. 14-740 CP 07000 Mexico D.F. Mexico Systems and Control Theory Group Max Planck Institute for Dynamics of Complex Technical Systems Sandtorstr. 1 D-39106 Magdeburg Germany

ISBN: (纸本)9783902661449

This paper addresses the problem of optimal design for linear networked control systems (NCSs). We deal with the delayed NCSs in the continuous time-domain and propose a computational approach to optimization problems based on the hybrid LQ-type techniques. In particular, we develop an explicit connection between the networked control processes and the corresponding hybrid systems. For the constructive feedback control design procedure we derive the necessary Riccati-formalism and propose an implementable solution algorithm. © 2009 IFAC.

关键词： Hybrid systems

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Application of high-performance computing for determining critical components of an energy system

Application of high-performance computing for determining cr...

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2020 Sustainable Development and Smart Management, ENERGY-21

作者： Edelev, Aleksey Feoktistov, Alexander Bychkov, Igor Basharina, Olga Melentiev Energy Systems Institute Sb Ras Lermontov St. 130 Irkutsk664033 Russia Matrosov Institute for System Dynamics and Control Theory Sb Ras Lermontov St. 134 Irkutsk664033 Russia

This article presents a package for analyzing the energy system vulnerability developed with new technology for continuous integration, delivery, and deployment of applied software. It implements a framework that allows combining and optimally using various methods for modelling energy systems and provides the comprehensive assessment of their vulnerability with regard to various uncertainties. The essential principles to identify and rank critical elements of an energy system are considered in the article. The investigations made with the package shown that the principles seem to be logical for the subsequent construction of the invariant set of measures for improving the energy system resilience. © The Authors, published by EDP Sciences, 2020.

关键词： Uncertainty analysis

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On stability, passivity and reciprocity preservation of ESVDMOR

On stability, passivity and reciprocity preservation of ESVD...

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Workshop on Model Reduction for Circuit Simulation

作者： Benner, Peter Schneider, André Max Planck Institute for Dynamics of Complex Technical Systems Computational Methods in Systems and Control Theory Sandtorstr. 1 39106 Magdeburg Germany Technische Universität Chemnitz Fakultät für Mathematik 09107 Chemnitz Germany

ISBN: (纸本)9789400700888

The reduction of parasitic linear subcircuits is one of many issues in model order reduction (MOR) for VLSI design. This issue is well explored, but recently the incorporation of subcircuits from different modelling sources into the circuit model has led to new structural aspects: so far, the number of elements in the subcircuits was significantly larger than the number of connections to the whole circuit, the so called pins or terminals. This assumption is no longer valid in all cases such that the simulation of these circuits or rather the reduction of the model requires new methods. In Feldmann and Liu (ICCAD '04: Proceedings of the 2004 IEEE/ACM International Conference on Computer-Aided Design, 88-92, 2004), Liu et al. (ICCAD '05: Proceedings of the 2005 IEEE/ACM International Conference on Computer-Aided Design, 821-826, 2004;Integr. VLSI J. 41(2):210-218, 2008) the extended singular value decomposition based model order reduction (ESVDMOR) algorithm is introduced as a way to handle this kind of circuits with a massive number of terminals. Unfortunately, the ESVDMOR approach has some drawbacks because it uses the SVD for matrix factorizations. In Benner (Mathematics in Industry 14, 2009), Schneider (Matrix decomposition based approaches for model order reduction of linear systems with a large number of terminals, 2008) the truncated SVD (TSVD) as an alternative to the SVD within the ESVDMOR is introduced. In this paper we show that ESVDMOR as well as the modified approach is stability, passivity, and reciprocity preserving under reasonable assumptions. © 2011 Springer Science+Business Media B.V.

关键词： Singular value decomposition

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On Active-Set Methods for Quadratic Problems with Positive Semidefinite Matrices 23rd

On Active-Set Methods for Quadratic Problems with Positive...

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23rd International Conference on Mathematical Optimization theory and Operations Research, MOTOR 2024

作者： Vasiliev, Igor Gruzdeva, Tatiana Barkova, Mariia Boyarkin, Denis Iakubovskii, Dmitrii Matrosov Institute for System Dynamics and Control Theory of SB RAS 134 Lermontov str. Irkutsk664033 Russia Melentiev Energy Systems Research Institute of SB RAS 130 Lermontov str. Irkutsk664033 Russia

ISBN: (纸本)9783031733642

Quadratic programming problems (QP) arise in a vast variety of real-world applications in finance, engineering, operational research, and many other fields. A huge number of methods and their various modifications have been developed for solving convex QPs. One of the first algorithms popularized as the solution method for QPs was the active-set method. The main idea of the method is selection of a set of binding constraints (an active set) and then iteratively adaptation it by adding and dropping constraints from the index set. The dual active-set (DAS) method of Goldfarb and Idnani is still well-known to be efficient and numerically stable. Taking advantage of the fact that the unconstrained minimum of the objective function can be used as a starting point of the method, its implementation utilizes the Cholesky and QR factorizations and procedures for updating them. At the same time, it suffers from the restriction that it cannot be applied to problems with positive semidefinite objective matrices, whereas in practice optimization problems may often be of such structure. We propose an add-in to the method of Goldfarb and Idnani that allows solving problems with positive semidefinite matrices directly by the DAS algorithm with a warm-start where a good estimate of the optimal active set is used to start the algorithm. The proposed technique is based on the well-known possibility of representing any matrix, as a difference of two, positive definite ones and solving then a sequence of so-called partially linearized problems. It can be viewed as a particular case of the special local search method for DC minimization problems. A computational experiment to testing the proposed approach was carried out on QPs with positive semidefinite objective matrices from the Maros and Meszaros test set. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Iterative methods

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Towards time-optimal exploration and control by an autonomous robot

Towards time-optimal exploration and control by an autonomou...

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Mediterranean Conference on control & Automation

作者： Vladislav Nenchev Jorg Raisch Technische Universitat Berlin Control Systems Group Max Planck Institute for Dynamics of Complex Technical Systems Systems and Control Theory Group

ISBN: (纸本)9781479909964

In this paper, we address the problem of an autonomous robotic vehicle collecting a finite but unknown number of objects with non-negligible masses and unknown locations in a restricted area and moving them to a particular spot in minimum time. An adaptive certainty-equivalent navigation and control policy is introduced based on a pick-up and an exploration/drop-off mode. While the input signal in pick-up mode is easily obtained in real time, complete exploration and drop-off corresponds to a hybrid optimal control problem (OCP) with exponential complexity in the finitely discretized space. We propose a trajectory planning algorithm by restricting the motion of the robot to a finite weighted graph. Further, we describe a discrete-time approximation of the hybrid OCP and compare both approaches with respect to computational complexity and accuracy.

关键词： Switches Vehicles Complexity theory Vehicle dynamics Optimization Robot sensing systems

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