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Model reference neural network controller for induction motor speed control

IEEE TRANSACTIONS ON ENERGY CONVERSION 2002年第2期17卷 157-163页

作者： Chen, TC Sheu, TT Natl Cheng Kung Univ Inst Engn Sci Tainan 70101 Taiwan

This paper proposes a novel robust speed control method for induction motor drives based on a two-layered neural network plant estimator (NNPE) and a two-layered neural network PI controller (NNPIC). The NNPE is used to provide a real-time adaptive estimation of the unknown motor dynamics. The widely used projection algorithm is used as the learning algorithm for these neural networks to automatically adjust the parameters of the NNPIC and to minimize the differences between the motor speed and the speed predicted by the NNPE. The simulation and experimental results demonstrate that the proposed robust control scheme can improve the performance of an induction motor drive and reduce its sensitivity to parameter variations and load disturbances.

关键词： induction motor neural network projection algorithm

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Distributed energy trading on networked energy hubs under network constraints

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RENEWABLE ENERGY 2023年第1期209卷 491-504页

作者： Wu, Yuxin Yan, Haoyuan Liu, Min Zhao, Tianyang Qiu, Jiayu Liu, Shengwei Jinan Univ Coll Informat Sci & Technol Guangzhou 510632 Peoples R China Jinan Univ Energy Elect Res Ctr Zhuhai 519070 Peoples R China

A distributed energy trading scheme with non-discriminatory pricing for a cluster of networked energy hubs (NEHs) is proposed. First, each energy hub (EH) is treated as a self-interested agent. The hybrid AC/DC microgrid (MG)-embedded EH model is proposed to optimize the operating costs under corresponding local energy balance constraints. The supply limits of the input energy systems, e.g., electrical feeders and natural gas pipelines, are represented as the global coupling constraints among NEHs. Then, to obtain the optimal operation and trading strategies, the distributed energy trading is formulated as a generalized Nash game (GNG). To ensure the solubility of the GNG problem, the existence and uniqueness of the generalized Nash equilibrium (GNE) are proved. Furthermore, to transform the complexity of the solution, the multivariable GNG problem is reformulated as a N+1 Nash game (NG) without coupling constraints, the equivalence between NG and the solution set of variational inequality (VI) problem is established. Then, an efficient distributed projection-based algorithm is proposed to compute a Nash equilibrium (NE) for the NG problem. Finally, a potential game-based centralized solution method is also implemented as a baseline, and the comparison of simulation results demonstrates the effectiveness of our proposed algorithm.

关键词： Distributed energy trading Networked energy hubs Non-discriminatory pricing Generalized Nash equilibrium N+1 Nash game projection algorithm

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Adaptive tracking with exponential stability and convolution bounds using vigilant estimation

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MATHEMATICS OF CONTROL SIGNALS AND SYSTEMS 2020年第3期32卷 241-291页

作者： Miller, Daniel E. Shahab, Mohamad T. Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

Classical discrete-time adaptive controllers provide asymptotic stabilization and tracking;neither exponential stabilization nor a bounded noise gain is typically proven. In our recent work, it is shown, in both the pole placement stability setting and the first-order one-step-ahead tracking setting, that if the original, ideal, projection algorithm is used (subject to the common assumption that the plant parameters lie in a convex, compact set and that the parameter estimates are restricted to that set) as part of the adaptive controller, then a linear-like convolution bound on the closed-loop behaviour can be proven;this immediately confers exponential stability and a bounded noise gain, and it can be leveraged to provide tolerance to unmodelled dynamics and plant parameter variation. In this paper, we solve the much harder problem of adaptive tracking;under classical assumptions on the set of unmodelled parameters, including the requirement that the plant be minimum phase, we are able to prove not only the linear-like properties discussed above, but also very desirable bounds on the tracking performance. We achieve this by using a modified version of the ideal projection algorithm, termed as vigilant estimator: it is equally alert when the plant state is large or small and is turned off when it is clear that the disturbance is overwhelming the estimation process.

关键词： Adaptive control projection algorithm Exponential stability Bounded gain Convolution bound

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Experimental and numerical investigation of nanofluid heat transfer in helically coiled tubes at constant wall heat flux

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ADVANCED POWDER TECHNOLOGY 2015年第5期26卷 1483-1494页

作者： Mirfendereski, Siamak Abbassi, Abbass Saffar-avval, Majid Amirkabir Univ Technol Tehran Polytech Dept Mech Engn Tehran Iran

The current study focuses on numerical and experimental investigation of the laminar, steady state flow in helical tubes with constant wall heat flux boundary condition. Pressure drop and convection heat transfer behavior of water-silver nanofluid in helical coils were evaluated and compared to the pure water. In the numerical part of the study, incompressible Navier-Stokes equations, derived from an orthogonal helical coordinate system were solved by finite difference method with projection algorithm using FORTRAN programming language. Homogeneous model with constant effective properties was used for nanofluid. The Local Nusselt number in the entrance region of the helical tubes and the effects of curvature and torsion ratios and Reynolds number have been discussed. In the experimental part, six helical heat exchangers with different curvature and torsion ratios were designed, capable of providing a constant wall heat flux. Pressure drop measurement and fully developed heat transfer coefficient and Nusselt number calculations were carried out and compared with the numerical results. The results show that for laminar flow with constant wall heat-flux boundary condition, the helical tubes with larger curvature ratio lead to higher heat transfer enhancement and higher pressure drop increase, when employing the nanofluid instead of the base fluid. Moreover, compared to using metal Ag nanofluid in straight tubes, utilization of base fluid in helical coils with greater curvature increases heat transfer more effectively. Finally, we conclude that since using Ag nanofluid increases the heat transfer of helical heat exchangers about 3.5-3.8%, utilizing this nanofluid could enhance the thermal performance of heat exchangers, which can benefit the industry. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.

关键词： Nanofluid Helically coiled tube Constant wall heat flux projection algorithm Experimental

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A new adaptive control of dual-motor driving servo system with backlash nonlinearity

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SADHANA-ACADEMY PROCEEDINGS IN ENGINEERING SCIENCES 2018年第10期43卷 1-10页

作者： Zhao, Haibo Wang, Chengguang Engn Technol Res Ctr Optoelect Appliance Tongling 244061 Anhui Peoples R China Tongling Univ Sch Elect Engn Tongling 244061 Anhui Peoples R China Sichuan Inst Aerosp Syst Engn Chengdu 610100 Sichuan Peoples R China

In order to weaken the influence of backlash nonlinearity on a dual-motor driving servo system, we first establish the state-space model of the system. We then propose a new adaptive controller combining a projection algorithm with backstepping control for the first time, to the best of our knowledge, and analyze its stability. In the simulation analysis, we respectively choose a triangular wave, sawtooth wave, and random signal as the input signal. Simulation results validate a higher tracking accuracy and stronger adaptability of the proposed control law than that of mere backstepping control. In the experimental tests, we respectively choose a step signal and sine signal and simultaneously apply a white noise signal to the system output after 3 s in each test. The test results validate a stronger adaptability and robustness than that of mere backstepping control.

关键词： Adaptive control backstepping control dual-motor driving projection algorithm backlash nonlinearity

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Galerkin spectral approximations for optimal control problems governed by the fourth order equation with an integral constraint on state

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2016年第10期72卷 2549-2561页

作者： Zhou, Jianwei Zhang, Juan Xing, Xiaoqing Linyi Univ Dept Math Linyi Peoples R China Shandong Normal Univ Sch Math Sci Jinan Peoples R China Bur Stat Lanshan Dist Linyi City Linyi Peoples R China South China Normal Univ Sch Math Sci Guangzhou Guangdong Peoples R China

An integral constraint on state optimal control problem governed by the first bi-harmonic equation is analyzed and its Legendre Galerkin spectral approximations are constructed. The optimality conditions of the continuous and the discretized optimal control problems are presented by the Kuhn-Tucker condition, respectively. The a priori error estimates of high accuracy are obtained. Furthermore, an efficient projection algorithm is proposed, and the convergent rate is discussed with precise details. Ample numerical examples are carried out to validate the theoretical results. (C) 2016 Elsevier Ltd. All rights reserved.

关键词： Optimal control State constraint projection algorithm Error estimate

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Linear-like properties arise naturally in the adaptive control setting

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INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING 2021年第6期35卷 965-990页

作者： Miller, Daniel E. Shahab, Mohamad T. Univ Waterloo Dept Elect & Comp Engn Waterloo ON N2L 3G1 Canada

Classical discrete-time adaptive controllers typically provide asymptotic stabilization and tracking;usually the affect of the noise is at best bounded-input bounded-output. Recently we have shown that if you design a discrete-time adaptive controller in just the right way, then in a variety of situations you not only obtain exponential stability, but also a bounded gain on the noise in every p-norm, as well as a never-before-seen linear-like convolution bound on the input-output behavior. Quite surprisingly, the approach is very natural, and relies on the use of the unmodified, original projection algorithm to carry out parameter estimation;if the set of plant uncertainty is not convex, then a multi-estimator and switching are used. The goal of this paper is to provide an overview of the approach, discuss the results-to-date, and list some of the open problems.

关键词： adaptive control bounded gain convolution bound exponential stability projection algorithm

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Nonlinear robust adaptive hierarchical sliding mode control approach for quadrotors

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INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL 2017年第6期27卷 925-941页

作者： Zou, Yao Beihang Univ Div Res 7 Beijing 100191 Peoples R China

This paper exploits a nonlinear robust adaptive hierarchical sliding mode control approach for quadrotors subject to thrust constraint and inertial parameter uncertainty to accomplish trajectory tracking missions. Because of under-actuated nature of the quadrotor, a hierarchical control strategy is available;and position and attitude loop controllers are synthesized according to adaptive sliding mode control projects, where adaptive updates with projection algorithm are developed to ensure bounded estimations for uncertain inertial parameters. Further, during the position loop controller development, an auxiliary dynamic system is introduced, and selection criteria for controller parameters are established to maintain the thrust constraint and to ensure the non-singular requirement of command attitude extraction. It has demonstrated that, the asymptotically stable trajectory tracking can be realized by the asymptotically stable cascaded closed-loop system and auxiliary dynamic system. Simulations validate and highlight the proposed control approach. (C) 2016 John Wiley & Sons, Ltd.

关键词： quadrotors hierarchical strategy adaptive sliding mode control projection algorithm auxiliary dynamic system

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On the solvability of a unilateral obstacle problem on the boundary

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2004年第1期162卷 193-199页

作者： Addou, A Zahi, J Univ Mohammed 1 Fac Sci Dept Math & Informat Oujda Morocco

关键词： obstacle penalization projection algorithm

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Numerical solution procedures for the morning commute problem

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MATHEMATICAL AND COMPUTER MODELLING 2009年第7-8期49卷 1295-1310页

作者： Nie, Yu (Marco) Zhang, Michael H. Northwestern Univ Dept Civil & Environm Engn Evanston IL 60208 USA Univ Calif Davis Dept Civil & Environm Engn Davis CA USA

This paper discusses solution techniques for the morning commute problem that is formulated as a discrete variational inequality(VI).Various heuristics have been proposed to solve this problem, mostly because the analytical properties of the path travel time function have not yet been well understood. Two groups of "non-heuristic''algorithms for general VIs, namely projection-type algorithms and ascent direction algorithms, were examined. In particular,a new ascent direction method is introduced and implemented with aheuristic line search procedure. The performance of these algorithms are compared on simple instances of the morning commute problem. The implications of numerical results are discussed. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Morning commute Variational inequality projection algorithm Ascent direction algorithm

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