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An extremum-seeking control approach for observer design

IFAC-PapersOnLine 2016年第18期49卷 678-683页

作者： Guay, M. Department of Chemical Engineering Queen's University KingstonON Canada

In this study, we propose to circumvent the difficulties associated with the computation of the observer gain for nonlinear systems by using an extremum-seeking control approach to generate optimal observer gains for a general class of nonlinear systems. This paper proposes a proportional-integral extremum-seeking control (PIESC) technique for the design of nonlinear observers. The PIESC technique is a generalization of the standard perturbation based techniques that provides fast transient performance of the closed-loop system to the optimum equilibrium of a measured objective function. In this application of PIESC, the gain of the nonlinear observer is computed in real-time to minimize the least-squares output prediction error. Two examples are used to demonstrate the effectiveness of this technique. © 2016

关键词： Control theory Closed loop systems Design Nonlinear systems Perturbation techniques Two term control systems Extremum seeking control Fast transients Non linear observer objective functions Observer design Optimal observers Output prediction errors Proportional integral

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Towards an optimisation of forging processes using geometric parameters

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JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 2006年第1-3期177卷 224-227页

作者： Khoury, Ibrahim Giraud-Moreau, Laurence Lafon, Pascal Labergere, Carl Univ Technol Troyes Charles Delaunay Inst Lab Mech Syst & Concurrent Engn F-10000 Troyes France

Nowadays computer simulation is used in metal forming to reduce the use of experimental investigation and tests required in a real tryout process. For much of the time, specialists have some freedom to obtain the desired forged parts, which is why numerical simulations are applied in most engineering offices and manufacturing industries to evaluate the forming difficulties in metal forming processes. In the mechanical system and concurrent engineering laboratory (LASMIS), a finite element package has been developed to solve elasto-plasticity problems with ductile damage in large deformation. In this article an experimental design is presented in order to show the influence of geometric parameters of a turbine engine disk on the total strain energy and the average of the elasto-plastic strain. (c) 2006 Elsevier B.V. All rights reserved.

关键词： geometric parameters objective functions forming process numerical simulation

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A generalized structure based on systemic principles of the characteristic variables of material laser processing

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OPTICS AND LASER TECHNOLOGY 2005年第7期37卷 577-581页

作者： Han, A Gubencu, D Pillon, G Burgundy Univ LTM Lab EA 2976 Chalon Sur Saone France Politehn Univ Timisoara Fac Mech Engn Timisoara Romania

The paper analyses the three main variables categories that are structurally characterizing the material laser processing: the influence factors, the process variables and the objective functions. These variables are divided in subsets determined by the system's structure, operating procedures and objectives of technological transformations. (c) 2004 Elsevier Ltd. All rights reserved.

关键词： laser processing systemic study independent variables objective functions

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Including Material Exposure and Part Attributes in the Manual Assembly Line Balancing Problem

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IFAC-PapersOnLine 2016年第12期49卷 926-931页

作者： Bortolini, M. Faccio, M. Gamberi, M. Pilati, F. University of Bologna Department of Industrial Engineering Viale del Risorgimento 2 Bologna40136 Italy University of Padova Department of Management and Engineering Stradella San Nicola 3 Vicenza36100 Italy

Assembly line balancing problem (ALBP) purpose is to assign assembly tasks to workstations optimizing a certain objective function. Despite this problem has been studied for decades, few contributions consider material exposure and part characteristics in ALBP. Furthermore, these features have relevant and practical implications for ALBP in the industrial context. This research proposes an innovative optimization model distinguished by different objective functions to properly balance assembly lines considering the aforementioned features. The model is tested and validated with a real industrial case study. The results demonstrates the importance of including material exposure and the optimal material storage within the assembly station in the assembly line balancing problem due to a strong influence of these on picking time, and so on the total assembly time. © 2016

关键词： Assembly Assembly machines Optimization Assembly line balancing problems Industrial case study Industrial context Manual assembly lines Material exposures objective functions Optimization modeling Part Attributes

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Pareto domain: an invaluable source of process information

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CHEMICAL PRODUCT AND PROCESS MODELING 2022年第1期17卷 29-53页

作者： Sepulveda, Geraldine Caceres Ochoa, Silvia Thibault, Jules Univ Ottawa Dept Chem & Biol Engn Ottawa ON K1N 6N5 Canada Univ Antioquia Dept Ingn Quim SIDCOP Res Grp Medellin Colombia

Due to the highly competitive market and increasingly stringent environmental regulations, it is paramount to operate chemical processes at their optimal point. In a typical process, there are usually many process variables (decision variables) that need to be selected in order to achieve a set of optimal objectives for which the process will be considered to operate optimally. Because some of the objectives are often contradictory, Multi-objective optimization (MOO) can be used to find a suitable trade-off among all objectives that will satisfy the decision maker. The first step is to circumscribe a well-defined Pareto domain, corresponding to the portion of the solution domain comprised of a large number of non-dominated solutions. The second step is to rank all Paretooptimal solutions based on some preferences of an expert of the process, this step being performed using visualization tools and/or a ranking algorithm. The last step is to implement the best solution to operate the process optimally. In this paper, after reviewing the main methods to solve MOO problems and to select the best Paretooptimal solution, four simple MOO problems will be solved to clearly demonstrate the wealth of information on a given process that can be obtained from the MOO instead of a single aggregate objective. The four optimization case studies are the design of a PI controller, an SO2 to SO3 reactor, a distillation column and an acrolein reactor. Results of these optimization case studies show the benefit of generating and using the Pareto domain to gain a deeper understanding of the underlying relationships between the various process variables and performance objectives.

关键词： decision variables objective functions pareto domain process optimization

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A Numerical Algorithm for Optimal Control of Systems with Parameter Uncertainty

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IFAC-PapersOnLine 2016年第18期49卷 468-475页

作者： Walton, Claire Phelps, Chris Gong, Qi Kaminer, Isaac Naval Postgraduate School MontereyCA93943 United States University of California Santa Cruz Santa CruzCA95060 United States

This paper describes a numerical scheme for computing optimal solutions to a class of nonlinear optimal control problems in which parameter uncertainty may be a feature of the state dynamics or objective function. Consistency results are provided for states and controls generated by the algorithm as well as for the adjoint variables. © 2016

关键词： Parameter estimation Numerical methods Optimal control systems Consistency result Non linear control Nonlinear optimal control problems Numerical algorithms objective functions Optimal controls Optimal solutions Parameter uncertainty

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A Parameterized NMPC Scheme for Embedded Control of Semi-active Suspension System⁎

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IFAC-PapersOnLine 2018年第20期51卷 301-306页

作者： Madhavan Rathai, Karthik Murali Alamir, Mazen Sename, Olivier Tang, Rattena Univ. Grenoble Alpes CNRS Grenoble INP GIPSA-labGrenoble38000 France

This paper proposes a parameterized NMPC scheme for control of semi-active suspension system for a quarter car vehicle model. The proposed controller is compared against a linearization based MPC to verify its performance under real-time (RT) embedded conditions. The linearization based MPC method linearizes the non-linear dynamical system/constraints at the current operating point and a linear MPC problem is solved by means of a quadratic program (QP) solver to obtain the optimal control input. The proposed parameterized NMPC method finitely parameterizes the control input and for each parameterized input, the nonlinear dynamical system is numerically simulated and the optimal input is elicited from the simulations which minimizes the objective function and satisfies the system constraints. The methods were considered on the basis of RT implementable scenario and practical viability for the target system. The methods were successfully tested by means of hardware in the loop (HIL) simulations under RT conditions for given control objective on dSPACE MicroAutoBox II hardware. The results from HIL simulations exudes better performance of parameterized NMPC against linearization based MPC in terms of computational efficiency and RT feasibility of the controller. © 2018

关键词： Suspensions (components) Active suspension systems Automobile suspensions Computational efficiency Controllers Dynamical systems Hardware Hardware in the loop simulation Linear control systems Linearization Model predictive control Nonlinear dynamical systems Parameterization Predictive control systems Quadratic programming Real time control Automotive control Control objectives Hardwarein the loop(HIL) simulation Nonlinear model predictive control objective functions Semi active suspension systems System constraints Vertical dynamics

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BUILDING MODELS OF VALUES

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EUROPEAN JOURNAL OF OPERATIONAL RESEARCH 1988年第2期37卷 149-157页

作者： KEENEY, RL UNIV SO CALIF DEPT SYST SCILOS ANGELESCA 90089 USA

To achieve a set of objectives, whether they are made explicit or not, is the entire intent of decisionmaking. When they are explicitly stated, the objectives are often quantified with an objective function. Because of its critical role for decisionmaking, the objective function should be developed from first principles, sound logic, reasoned judgments, and carefully acquired consistent data. Unfortunately, in practice many objective functions are hastily chosen froma process that can at best be described as arbitrary. This paper presents a better alternative for developing the objective function, namely to construct it from a quality modelling effort.

关键词： decision analysis objective functions utility functions value model

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Modeling and optimization of biomass supply chains: A review and a critical look

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IFAC-PapersOnLine 2016年第12期49卷 604-615页

作者： Atashbar, N. Zandi Labadie, N. Prins, C. CS 42060 Troyes10004 France

Due to the effect of greenhouse gas emissions and increasing energy demand, consumption of more sustainable and renewable energies has increased. Biofuels derived from biomass can play a key-role nowadays as one of the main sources of renewable energies. Therefore, more and more researchers have been involved in modeling and optimizing biomass supply chains. This paper presents an overview of biomass supply chains. After an outline of the main definitions and a description of typical activities in biomass supply chain; a classification of optimization methods and models developed in this context is detailed. All selected papers are classified and discussed according to (1) objective functions, (2) decision levels and (3) solution methods. Finally, a critical look at current researches and possible new directions are presented. © 2016

关键词： Biomass Biofuels Gas emissions Greenhouse effect Greenhouse gases Logistics Models Optimization Supply chains Biomass supply chain Decision levels Energy demands Modeling and optimization objective functions Optimization method Renewable energies Solution methods

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Effective Multi-Modal Retrieval based on Stacked Auto-Encoders

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PROCEEDINGS OF THE VLDB ENDOWMENT 2014年第8期7卷 649-660页

作者： Wang, Wei Ooi, Beng Chin Yang, Xiaoyan Zhang, Dongxiang Zhuang, Yueting Natl Univ Singapore Sch Comp Singapore Singapore Illinois Singapore Pte Adv Digital Sci Ctr Singapore Singapore Zhejiang Univ Coll Comp Sci Hangzhou Zhejiang Peoples R China

Multi-modal retrieval is emerging as a new search paradigm that enables seamless information retrieval from various types of media. For example, users can simply snap a movie poster to search relevant reviews and trailers. To solve the problem, a set of mapping functions are learned to project high-dimensional features extracted from data of different media types into a common lowdimensional space so that metric distance measures can be applied. In this paper, we propose an effective mapping mechanism based on deep learning (i.e., stacked auto-encoders) for multi-modal retrieval. Mapping functions are learned by optimizing a new objective function, which captures both intra-modal and inter-modal semantic relationships of data from heterogeneous sources effectively. Compared with previous works which require a substantial amount of prior knowledge such as similarity matrices of intra-modal data and ranking examples, our method requires little prior knowledge. Given a large training dataset, we split it into mini-batches and continually adjust the mapping functions for each batch of input. Hence, our method is memory efficient with respect to the data volume. Experiments on three real datasets illustrate that our proposed method achieves significant improvement in search accuracy over the state-of-the-art methods.

关键词： Signal encoding Deep learning Mapping Semantics Heterogeneous sources High dimensional feature Low dimensional spaces Mapping functions Mapping mechanism Metric distances objective functions State of the art methods

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