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Vehicle Suspension Identification Via Algorithmic Computation of State and Design Sensitivities

JOURNAL OF MECHANICAL DESIGN 2015年第2期137卷 1-9页

作者： Callejo, Alfonso Garcia de Jalon, Javier Wichita State Univ Natl Inst Aviat Res Wichita KS 67260 USA Univ Politecn Madrid ETSII E-28006 Madrid Spain Univ Politecn Madrid INSIA E-28006 Madrid Spain Univ Politecn Madrid INSIA Madrid 28031 Spain

It is common in mechanical simulation to not know the value of key system parameters. When the simulation is very sensitive to those design parameters and practical or budget limitations prevent the user from measuring the real values, parameter identification methods become essential. Kalman filter methods and optimization methods are the most widespread approaches for the identification of unknown parameters in multibody systems. A novel gradient-based optimization method, based on sensitivity analyses for the computation of machine-precision gradients, is presented in this paper. The direct differentiation approach, together with the algorithmic differentiation of derivative terms, is employed to compute state and design sensitivities. This results in an automated, general-purpose and robust method for the identification of parameters. The method is applied to the identification of a real-life vehicle suspension system (namely of five stiffness coefficients) where both smooth and noisy reference responses are considered. The identified values are very close to the reference ones, and everything is carried out with limited user intervention and no manual computation of derivatives.

关键词： AUTOMOBILES -- Springs & suspension -- Design & construction PARAMETER identification KALMAN filtering SYSTEMS design computer algorithms SIMULATION methods & models

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A DNA Algorithm for the maximal matching problem

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AUTOMATION AND REMOTE CONTROL 2015年第10期76卷 1797-1802页

作者： Li Wenxia Patrikeev, E. M. Xiao Dongmei E China Normal Univ Shanghai 200062 Peoples R China Jiao Tong Univ Shanghai 200030 Peoples R China

We propose a procedure for solving the classical discrete extremal maximal matching problem with the Adleman-Lipton model as the computational architecture. We show that for an undirected graph with n edges the soluti... 详细信息

关键词： MOLECULAR computers DNA computer algorithms AUTOMATIC control REMOTE control BINARY control systems NUMERICAL analysis

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A Two-Sided Matching Decision Model Based on Uncertain Preference Sequences

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-10页

作者： Liu, Xiao Ma, Huimin Huazhong Univ Sci & Technol Sch Management Wuhan 430074 Peoples R China

Two-sided matching is a hot issue in the field of operation research and decision analysis. This paper reviews the typical two-sided matching models and their limitations in some specific contexts, and then puts forward a new decision model based on uncertain preference sequences. In this model, we first design a data processing method to get preference ordinal value in uncertain preference sequence, then compute the preference distance of each matching pair based on these certain preference ordinal values, set the optimal objectives as maximizing matching number and minimizing total sum of preference distances of all the matching pairs under the lowest threshold constraint of matching effect, and then solve it with branch-and-bound algorithm. Meanwhile, we take two numeral cases as examples and analyze the different matching solutions with one-norm distance, two-norm distance, and positive-infinity-normdistance, respectively. We also compare our decision model with two other approaches, and summarize their characteristics on two-sided matching.

关键词： DECISION making COMPARATIVE studies CONSUMERS' preferences computer algorithms ELECTRONIC data processing

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Solving the Maximum Weighted Clique Problem Based on Parallel Biological Computing Model

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-8页

作者： Wang, Zhaocai Qin, Jiangfeng Ji, Zuwen Huang, Dongmei Li, Lei Shanghai Ocean Univ Sch Informat Sci Shanghai 201306 Peoples R China Guangxi Inst Water Resources Res Nanning 530023 Peoples R China China Inst Water Resources & Hydropower Res State Key Lab Simulat & Regulat River Basin Water Beijing 100048 Peoples R China Xian Univ Architecture & Technol Dept Civil Engn Xian 710055 Peoples R China

The maximum weighted clique (MWC) problem, as a typical NP-complete problem, is difficult to be solved by the electronic computer algorithm. The aim of the problem is to seek a vertex clique with maximal weight sum in a given undirected graph. It is an extremely important problem in the field of optimal engineering scheme and control with numerous practical applications. From the point of view of practice, we give a parallel biological algorithm to solve the MWC problem. For the maximum weighted clique problem with.. edges and.. vertices, we use fixed length DNA strands to represent different vertices and edges, fully conduct biochemical reaction, and find the solution to the MVC problem in certain length range with O(n(2)) time complexity, comparing to the exponential time level by previous computer algorithms. We expand the applied scope of parallel biological computation and reduce computational complexity of practical engineering problems. Meanwhile, we provide a meaningful reference for solving other complex problems.

关键词： PARALLEL computers BIOLOGICAL models computer algorithms BIOMEDICAL engineering UNDIRECTED graphs VERTICES (Geometry)

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Sequential quadratic programming for the control of an architectural cable net geometry

Sequential quadratic programming for the control of an archi...

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American Control Conference

作者： Yvonne R. Sturz Manfred Morari Roy S. Smith Automatic Control Laboratory ETH Zurich Switzerland

ISBN: (纸本)9781467386838

In order to efficiently construct anticlastic concrete shell structures in architecture, flexible formwork can be used, whose main component is a cable net under tension. To cope with the fabrication tolerances of the cable net and thus to reduce the deviations between the nominal digital design model and the as-built one, which is needed to guarantee the properties of the shell, we propose a control algorithm which iteratively steers the geometry of the cable net to the desired one. Our contribution in this paper is twofold. We formulate an optimal control problem and provide two different formulations of the nonlinear equality and inequality constraints. Whereas one of the formulations is a set of implicit nonlinear equations, the other one is the solution to a second-order cone program, which can efficiently be solved. We use both formulations and combine them into a control algorithm, which is based on Sequential Quadratic Programming (SQP), and where the solution in each iteration is feasible for the nonlinear constraints. A simulation example is presented to demonstrate the performance of the developed control algorithm.

关键词： Artificial neural networks Geometry Noise measurement Buildings Topology Force Fabrication computer algorithms Noise measurement geometry sequential quadratic programming Buildings Artificial neural networks topology Force cable fabrication Nets built structure manufacturing tolerances

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Control bandwidth recovery of flexible pointing systems

Control bandwidth recovery of flexible pointing systems

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American Control Conference

作者： David E. Zlotnik James R. Forbes Jack B. Aldrich Department of Aerospace Engineering University of Michigan Ann Arbor 48109 USA Department of Mechanical Engineering McGill University Montreal QC H3A 0C3 Canada Jet Propulsion Lab California Inst. of Technology Pasadena 91109 USA

ISBN: (纸本)9781467386838

Instrument pointing control systems mounted on spacecraft are inherently bandwidth-limited (due to lightly-damped flexible modes of the spacecraft) compared to the same system mounted to a rigid body (such as the ground). This work is concerned with the recovery of control bandwidth for space-based pointing systems via the application of μ-tip control, a passivity-based control methodology. First, the equations of motion of a pointing system are derived. Then, using a "massive payload assumption" a passive input-output map is established between a modified output, called the μ-tip rate, and a modified control input. Bandwidth recovery is confirmed by investigating the frequency response of the linearized system. Simulation results that demonstrate the performance of the developed control algorithm are presented.

关键词： Bandwidth Mathematical model Space vehicles Control systems Electronic mail Kinematics Potential energy Bandwidth Space vehicles electronic mail control systems Potential energy kinematics Mathematical Model Spacecraft computer algorithms frequency response Control Methods

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Controlled Passage through Resonance for Flexible Vibration Units

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MATHEMATICAL PROBLEMS IN ENGINEERING 2015年第1期2015卷 1-8页

作者： Tomchin, Dmitry A. Tomchina, Olga P. Fradkov, Alexander L. Inst Problems Mech Engn St Petersburg 199178 Russia St Petersburg State Univ Architecture & Civil Eng St Petersburg 190005 Russia St Petersburg State Univ Univ ITMO St Petersburg 199178 Russia

The problem of controlled passage through resonance zone for mechanical systems with several degrees of freedom is studied. Control algorithm design is based on speed-gradient method and estimate for the frequency of the slow motion near resonance (Blekhman frequency). The simulation results for two-rotor flexible vibration units illustrating efficiency of the proposed algorithms and fractal dependence of the passage time on the initial conditions are presented. The novelty of the results is in demonstration of good behavior of the closed loop system if flexibility is taken into account.

关键词： RESONANCE DEGREES of freedom CLOSED loop systems computer algorithms FREQUENCIES of oscillating systems algorithms

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Residual Least-Squares Error Estimate for Unstructured h-Adaptive Meshes

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NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS 2015年第3期67卷 187-210页

作者： Albuquerque, Duarte M. S. Pereira, Jose M. C. Pereira, Jose C. F. Univ Lisbon LAETA IDMEC Inst Super Tecn P-1049001 Lisbon Portugal

An a posteriori error estimate suitable for finite-volume adaptive computations is presented. The error estimate combines the least-squares method regressions with the residual computation, which provides information from the grid quality and the governing equations for a better local adaptation of the unstructured grid. The decision algorithm uses the information provided by the error estimate and does not require problem-dependent constants;it also uses a grid interface correction step to provide a smoother and a high-quality adaptive grid. The proposed error estimate and the adaptive refinement algorithm are verified against analytic solution for different two-dimensional problems. In addition, calculations of three-dimensional laminar flows with different types of unstructured grids have demonstrated the applicability of the adaptive method.

关键词： Laminar flow Decision making Least squares Error analysis (Mathematics) computer algorithms Numerical calculations

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Stochastic gradient algorithm for multi-input multi-output Hammerstein FIR-MA-like systems using the data filtering

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JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS 2015年第4期352卷 1440-1454页

作者： Wang, Ziyun Wang, Yan Ji, Zhicheng Jiangnan Univ Minist Educ Key Lab Adv Proc Control Light Ind Wuxi 214122 Peoples R China

This paper presents a data filtering based stochastic gradient algorithm for estimating the parameters of multivariable Hammerstein FIR-MA-like systems. By filtering the input and output data, the FIR-MA-like model is transformed into a controlled autoregressive model. The examples confirm that the proposed algorithm is more accurate and has a better performance than the stochastic gradient algorithm. (C) 2015 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

关键词： STOCHASTIC analysis computer algorithms HAMMERSTEIN equations DATA analysis AUTOREGRESSIVE processes

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An Automatic Parachute Separation System for Aerial Dispersal Miniature Reconnaissance Robot

An Automatic Parachute Separation System for Aerial Dispersa...

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Chinese Control and Decision Conference

作者： Yao Chen Xuanyang Shi Intelligent Robotics Institute Key Laboratory of Biomimetic Robots and Systems Ministry of Education School of Mechatronical Engineering Beijing Institute of Technology

ISBN: (纸本)9781467397155

The kernel of the system is an intelligent control algorithm which can recognize precisely the whole dropping-process from launch module starting up to the miniature robots touching down and then determine whether the robot lands finally. The controller will activate a motor to realize the separation of parachute from the landed robot. This article, based on research into the principle of the system, proposes a control algorithm utilizing a 3-axis digital accelerometer. At last, the related experiments shows that the approach is effectual.

关键词： Intelligent control algorithm Recognize dropping-process Separation of parachute 3-axis digital accelerometer computer algorithms Miniature Robot ANTENNA Seed Dispersal dispersal (organisms) Motor separation AUTOMATIC Intelligent control

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