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A constrained optimal PID-like controller design for spacecraft attitude stabilization

ACTA ASTRONAUTICA 2012年 74卷 131-140页

作者： Li, Chuanjiang Teo, Kok Lay Li, Bin Ma, Guangfu Harbin Inst Technol Dept Control Sci & Engn Harbin 150001 Peoples R China Curtin Univ Dept Math & Stat Perth WA 6845 Australia Harbin Inst Technol Ctr Control Theory & Guidance Technol Harbin 150001 Peoples R China

In this paper, an optimal PID-like controller is proposed for a spacecraft attitude stabilization problem subject to continuous inequality constraints on the spacecraft angular velocity and control, as well as terminal constraints on the spacecraft attitude and angular velocity. The closed-loop stability is established using the Lyapunov stability theory. The constraint transcription method and a local smoothing technique are used to construct a smooth approximate function for each of the continuous inequality constraints on the angular velocity and control. Then, by using the concept of the penalty function, these approximate smooth functions are appended to the quadratic performance criterion forming an augmented cost function. Consequently, the constrained optimal control problem under the PID-like controller is approximated by a sequence of optimal parameter selection problems subject to only terminal constraints on the spacecraft attitudes. A reliable computational algorithm is derived for the tuning of the optimal PID-like control parameters. Finally, numerical simulations are carried out to illustrate the effectiveness of the methodology proposed. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Spacecraft attitude stabilization Closed-loop stability Optimal PID-like controller Optimal parameter selection problem numerical algorithm

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Quasi 3D modeling of water flow in vadose zone and groundwater

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JOURNAL OF HYDROLOGY 2012年 450卷 140-149页

作者： Kuznetsov, M. Yakirevich, A. Pachepsky, Y. A. Sorek, S. Weisbrod, N. USDA ARS Environm Microbial & Food Safety Lab Beltsville MD 20705 USA Ben Gurion Univ Negev Zuckerberg Inst Water Res Dept Environm Hydrol & Microbiol J Blaustein Inst Desert Res IL-84105 Beer Sheva Israel

The complexity of subsurface flow systems calls for a variety of concepts leading to the multiplicity of simplified flow models. One habitual simplification is based on the assumption that lateral flow and transport in unsaturated zone are not significant unless the capillary fringe is involved. In such cases the flow and transport in the unsaturated zone above groundwater level can be simulated as a 1D phenomenon, whereas the flow and transport through groundwater are viewed as 2D or 3D phenomena. A new approach for a numerical scheme for 3D variably saturated flow using quasi 3D Richards' equation and finite difference scheme is presented. The corresponding numerical algorithm and the QUASI-3D computer code were developed. Results of the groundwater level simulations were compared with transient laboratory experimental data for 2D data constant-flux infiltration, quasi-3D HYDRUS-MODFLOW numerical model and a FULL-3D numerical model using Richards' equation. Hypothetical 3D examples of infiltration, pumping and groundwater mound dissipation for different spatial-time scales are presented. Water flow simulation for the Alto Piura aquifer (Peru) demonstrates the QUASI-3D model application at the regional scale. Computationally the QUASI-3D code was found to be more efficient by an order of 10-300%, while being accurate with respect to the benchmark fully 3D variable saturation code, when the capillary fringe was considered. Published by Elsevier B.V.

关键词： Vadose zone Groundwater Capillary fringe Quasi three-dimensional approach numerical algorithm

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Control optimization in a hyperbolic linear system

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COMPUTATIONAL MATHEMATICS AND MATHEMATICAL PHYSICS 2012年第1期52卷 4-19页

作者： Tyatyushkin, A. I. Russian Acad Sci Siberian Branch Inst Syst Dynam & Control Theory Irkutsk 664033 Russia

An optimal control problem is considered for a distributed-parameter Goursat-Darboux system with controlled boundary conditions. For the numerical solution of the problem, an algorithm based on separability and minimax theorems is constructed, which reduces the problem to finding the maximum of a concave functional defined in the class of one-variable functions.

关键词： numerical algorithm optimal control distributed parameter system

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Quasi-gasdynamic numerical algorithm for gas flow simulations

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INTERNATIONAL JOURNAL FOR numerical METHODS IN FLUIDS 2008年第8期56卷 1209-1215页

作者： Elizarova, T. G. Khokhlov, A. A. Sheretov, Yu. V. Russian Acad Sci Inst Math Modeling Moscow 125047 Russia Moscow MV Lomonosov State Univ Fac Phys Moscow 119992 Russia Tver State Univ Tver 170013 Russia

The quasi-gasdynamic equation system and the numerical algorithm for non-stationary viscous gasdynamic flow calculations are presented. The quasi-gasdynamic equation system generalizes the Navier-Stokes equations and differs from it by the additional dissipative terms. The numerical examples are presented. Copyright (C) 2007 John Wiley & Sons, Ltd.

关键词： quasi-gasdynamic equations numerical algorithm compressible flows

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Fragmentation of numerical algorithms for parallel subroutines library

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JOURNAL OF SUPERCOMPUTING 2011年第2期57卷 161-171页

作者： Kireev, S. Malyshkin, V. Russian Acad Sci Inst Computat Math & Math Geophys Siberian Branch Novosibirsk Russia

Fragmentation is a well-known method of the parallelization of numerical algorithms and programs. algorithm fragmentation allows creating fragmented parallel programs that can be executed on parallel computers of different types (multiprocessors and/or multicomputers) and can be dynamically tuned to all the available resources. Fragmentation of the often used numerical algorithms, their representation for inclusion into the library of parallel numerical subroutines and properties of the runtime system are considered.

关键词： Asynchronous programming Parallel program numerical algorithm Fragment-based programming Dynamic programs' properties

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High-stability numerical algorithm for the simulation of deformable electrostatic MEMS devices

High-stability numerical algorithm for the simulation of def...

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Nanotechnology Conference and Trade Show (Nanotech 2008)

作者： Rottenberg, X. Nauwelaers, B. De Raedt, W. Elata, D. IMEC VZW Div MCP Kapeldreef 75 B-3001 Louvain Belgium

ISBN: (纸本)9781420085051

This paper presents a novel high-stability electrically-driven algorithm for the simulation of the electromechanical actuation of electrostatic MEMS devices. The stability of this algorithm improves on that of voltage- and charge-drive algorithms. Key in our algorithm are the use of a local charge density as driver for an adapted relaxation algorithm and the adequate selection of the bias node in the mesh. The high stability of this algorithm allows probing the electromechanical equilibrium locus way beyond the V-and Q-drive pull-in instabilities. The new algorithm allows investigating the effect of dielectric charging in deformable electrostatic MEMS devices and especially the narrowing of their equilibrium locus due to dielectric charging non-uniformities. We implement this algorithm in 2D for clamped-clamped beams of rectangular cross-section and take into account, among other things, distributed dielectric thickness, permittivity, rest air gap, actuation electrode and linearly distributed dielectric roughness.

关键词： dielectric charging electrostatic actuation numerical algorithm high stability

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Quasi-gasdynamic numerical algorithm for gas flow simulations

Quasi-gasdynamic numerical algorithm for gas flow simulation...

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9th ICFD Conference on numerical Methods for Fluid Dynamics

关键词： quasi-gasdynamic equations numerical algorithm compressible flows

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A Virtual Training System Based on Computer Sensing and Football Kicking Dynamics Using Real-Time Wireless Feedback 13

A Virtual Training System Based on Computer Sensing and Foot...

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Simulation Multiconference

作者： Alyssa Schaefbauer Cole Meyers Aaron Stout Ehren Biglari Jacob Kantor Yusheng Feng University of Texas at San Antonio

ISBN: (纸本)9781627482769

Most football simulators available use computer simulation to mimic football motion in a virtual environment. These kinds of simulations, while fun and interactive, are primarily for entertainment rather than as a training tool. In this paper, we present a virtual training system for football kicking based on computer sensing and football impact dynamics using real-time wireless feedback. It is designed as a computer-assisted training system that will give a kicker the ability to practice off the field and receive the detailed feedback comparable yet more quantitative than they would experience at a training camp. In addition, it enables football coaches with quantitative data to design player-specific training program for kickers in order to achieve a goal with more precision. The system includes a force-sensing panel to determine the position and velocity as initial data, real-time wireless feedback to calibrate the football kicking dynamics model, and an advanced visualization environment designed to recreate the realistic atmosphere of all major football stadiums. The system has been designed and tested in a lab environment. The preliminary results show that the wireless signal is sensitive enough to detect football positions on the fly. The data collected in real-time can be used to calibrate the football dynamics model in predicting the final position of the football with respect to the field goal, which is visualized using 3D stereoscopic technology.

关键词： Real-Time Prediction numerical algorithm Pressure Sensor Array Virtual Environment Computer-Assisted Training

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ADVANCED KINEMATIC SCHEME OF STRUCTURAL CALCULATION OF THIN MULTILAYER LAMINATE WITH ESSENTIALLY DIVERSE LAYER'S STIFFNESS

ADVANCED KINEMATIC SCHEME OF STRUCTURAL CALCULATION OF THIN ...

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ASME International Mechanical Engineering Congress and Exposition (IMECE)

作者： Gaynutdinov, V. G. Kazan State Tech Univ AN Tupolev Dept Aircraft Design Kazan Russia

ISBN: (纸本)9780791854877

Composite structure consists of a system of layers bonded together. The layers can have different mechanical properties and thicknesses. The main task is to predict the behavior of a laminate as a system of layers with given properties. We suggest advanced kinematic scheme for structural calculation and heuristic numerical algorithm of prediction behavior of a multilayer structures with essentially diverse layer's stiffness. Kinematic scheme can be compared in adequacy with three-dimensional approach of structural calculation of thin multilayer laminate, but is more economical in view of required resource for numerical calculation.

关键词： thin multilayer structure advanced kinematic scheme numerical algorithm structural calculation

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Conditional Parameter Identification with Asymmetrical Losses of Estimation Errors

Conditional Parameter Identification with Asymmetrical Losse...

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4th International Conference on Computational Collective Intelligence - Technologies and Applications (ICCCI)

作者： Kulczycki, Piotr Charytanowicz, Malgorzata Polish Acad Sci Syst Res Inst Ctr Informat Technol Data Anal Methods PL-01447 Warsaw Poland

ISBN: (纸本)9783642346309

In many scientific and practical tasks, the classical concepts for parameter identification are satisfactory and generally applied with success, although many specialized problems necessitate the use of methods created with specifically defined assumptions and conditions. This paper investigates the method of parameter identification for the case where losses resulting from estimation errors can be described in polynomial form with additional asymmetry representing different results of under- and overestimation. Most importantly, the method presented here considers the conditionality of this parameter, which in practice means its significant dependence on other quantities whose values can be obtained metrologically. To solve a problem in this form the Bayes approach was used, allowing a minimum expected value of losses to be achieved. The methodology was based on the nonparametric technique of statistical kernel estimators, which freed the worked out procedure from forms of probability distributions characterizing both the parameter under investigation and conditioning quantities. As a result, a ready to direct use algorithm has been presented here.

关键词： parameter identification Bayes approach asymmetrical losses of estimation errors conditional factors nonparametric estimation statistical kernel estimators numerical algorithm

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