检索结果-内蒙古大学图书馆

Inverse design method for transonic multiple wing systems using integral equations

JOURNAL OF AIRCRAFT 1997年第3期34卷 322-329页

作者： Matsushima, K Takanashi, S Iwamiya, T NATL AEROSP LAB COMPUTAT AERODYNAM LABAIRCRAFT AERODYNAM DIVTOKYO 182JAPAN NATL AEROSP LAB APPL MATH LABCOMPUTAT SCI DIVTOKYO 182JAPAN

An inverse design method that treats multiple wings (or multicomponents of a wing) is proposed and examined, The method takes into consideration the mutual interaction among wings, It designs the section shapes of wings that realize a specified surface pressure distribution, It can he applied to two- and three-dimensional aerodynamic design problems in various degrees of a flowfield, potential flow, inviscid and viscous flow, subsonic and transonic flow. The primary idea is the extension of an integral equation method, An inverse problem is reformulated in terms of integral equations that express the relation of pressure differences to geometrical changes of wing sections for a multiple wing system. Most of the integral calculation is done analytically and the equations are solved numerically by introducing piecewise function approximation, This method works well on several preliminary design problems in transonic and high subsonic flows. From the practical point of view, it is promising for complicated aerodynamic design.

关键词： Inverse Problems Prandtl Glauert Transformation Angle of Attack Total Variation Diminishing Wing Geometry NACA 0012 Navier Stokes Simulation Stagnation Point numerical Optimization numerical algorithms

来源：评论

学校读者我要写书评

暂无评论

numerically efficient robustness analysis of trajectory tracking for nonlinear systems

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1997年第4期20卷 640-647页

作者： Tierno, JE Murray, RM Doyle, JC Gregory, IM CALTECH PASADENACA 91125 NASA LANGLEY RES CTRDEPT FLIGHT DYNAM & CONTROLHAMPTONVA 23681

A numerical algorithm for computing necessary conditions for performance specifications is developed for nonlinear uncertain systems that follow a prescribed trajectory, This algorithm provides a computationally efficient means of evaluating the performance of a nonlinear system in the presence of noise, real parametric uncertainty, and unmodeled dynamics, The algorithm is similar in nature and behavior to the power algorithm for the structured singular value (mu) lower bound and does not rely on a descent method, The algorithm is tested on a Eight control example.

关键词： Mathematical Models Computing numerical algorithms Monte Carlo Simulation Aeroplane Linear Time Invariant Ailerons Computing Structures Boundary Value Problems Iterative Algorithm

来源：评论

学校读者我要写书评

暂无评论

Close-approach trajectories in the elliptic restricted problem

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1997年第4期20卷 797-802页

作者： Prado, AFBD Instituto Nacional de Pesquisas Espaciais Sao Paulo Jose dos Campos Sao Paulo 12227-010 Brazil

The swing-by maneuver uses a close approach with a celestial body to modify the velocity, energy, and angular momentum of a spacecraft's orbit. The swing-by trajectories are studied and classified under the model given by the elliptic restricted three-body problem. Several simulations are made to show the effects of the eccentricity of the primaries in this maneuver. The position of the secondary in its orbit (specified by its true anomaly) also has effects on the results, and they are quantified. To show the results, the orbit of the spacecraft is classified in four groups: elliptic direct, elliptic retrograde, hyperbolic direct, and hyperbolic retrograde. Then the modification in the orbit of the spacecraft due to the close approach is shown in plots that specify from which group the spacecraft's orbit is coming and to which group it is going. Several families of orbits are found and shown in detail. An analysis about the trends as parameters vary is performed, and the influence of each of them is shown and explained. The results presented can also be used to find optimal sets of parameters for several types of problems, such as finding an escape orbit that has minimum velocity at periapsis and other related problems.

关键词： Periapsis Giant Planet numerical Integration Patched Conic Approximation numerical Simulation Celestial Mechanics numerical algorithms Spacecraft Orbits Runge Kutta Methods Keplerian Orbit

来源：评论

学校读者我要写书评

暂无评论

Development of closed-loop tail-sizing criteria for a High Speed Civil Transport

引用

JOURNAL OF AIRCRAFT 1997年第5期34卷 658-664页

作者： Kaminer, II Howard, RM Buttrill, CS NASA LANGLEY RES CTRDYNAM & CONTROL BRANCHHAMPTONVA 23681

A study was conducted to determine the closed-loop tail-sizing criteria for a High Speed Civil Transport using a newly developed integrated aircraft/controller design methodology. The key idea is to cast closed loop requirements as linear matrix inequalities, for which efficient numerical solvers are available, In particular, the effects of certain feedback specifications, and of actuator amplitude and rate constraints on the maximum allowable e.g. travel for a given set of tail sizes are studied, A constant gain slate feedback controller Is designed as a part of the tail-sizing process.

关键词： High Speed Civil Transport Closed Loop Transfer Function Supersonic Aircraft Damping Ratio Angle of Attack Federal Aviation Regulation numerical algorithms Aircraft Dynamics Aerodynamic Center Stability Augmentation

来源：评论

学校读者我要写书评

暂无评论

General matrix pencil techniques for the solution of algebraic Riccati equations: A unified approach

引用

IEEE TRANSACTIONS ON AUTOMATIC CONTROL 1997年第8期42卷 1085-1097页

作者： Ionescu, V Oara, C Weiss, M TECH UNIV EINDHOVEN FAC APPL PHYS NL-5600 MB EINDHOVEN NETHERLANDS

We present a unified theory of matrix pencil techniques for solving both continuous and discrete-time algebraic Riccati equations (ARE's) under fairly general conditions on the coefficient matrices, The theory applies to a large class of ARE's and Riccati-like equations arising from the singular H-infinity- and H-2- control problems, singular linear quadratic control, the ii-block Nehari problem, or from singular J-spectral factorizations. The underlying concept is the so-called proper deflating subspace of a (possibly singular) matrix pencil in terms of which necessary and sufficient conditions for the solvability of Riccati equations are given, It is shown that these conditions can be checked and the solutions computed by a numerically sound algorithm.

关键词： matrix pencils numerical algorithms Riccati equations spectral factorizations

来源：评论

学校读者我要写书评

暂无评论

A control-based approach to the solution of nonlinear algebraic equations

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-FUNDAMENTAL THEORY AND APPLICATIONS 1997年第4期44卷 366-369页

作者： Brambilla, A DAmore, D Dipartimento di Elettronica ed Informazione Politecnico di Milano Milan Italy Politecnico di Milano Milano Lombardia IT

A different approach to the solution of a nonlinear set of algebraic equations is presented. It is basically a revision of the Newton iterative algorithm from a digital control point of view, The Newton algorithm is considered like a digital control algorithm that acts on a set of nonlinear algebraic equations. Its target is to find a value x* that satisfies the algebraic equation set. This value can be considered as a particular ''input'' of the equation set which gives a zero ''output'' while the iteration index can be considered as the clock of the digital system. From this point of view some correlations between the stability of digital systems and the Newton algorithm can be shown, This approach allows us to understand the reasons behind the convergence failure of some modified Newton algorithms such as source stepping, damping, and limiting that literature often reports as heuristic.

关键词： electrical simulation numerical algorithms

来源：评论

学校读者我要写书评

暂无评论

Design of materials with extreme thermal expansion using a three-phase topology optimization method

引用

JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 1997年第6期45卷 1037-1067页

作者： Sigmund, O Torquato, S PRINCETON UNIV DEPT CIVIL ENGN & OPERAT RES PRINCETON NJ 08544 USA PRINCETON UNIV PRINCETON MAT INST PRINCETON NJ 08544 USA

Composites with extremal or unusual thermal expansion coefficients are designed using a three-phase topology optimization method. The composites are made of two different material phases and a void phase. The topology optimization method consists in finding the distribution of material phases that optimizes an objective function (e.g. thermoelastic properties) subject to certain constraints, such as elastic symmetry or volume fractions of the constituent phases, within a periodic base cell. The effective properties of the material structures are found using the numerical homogenization method based on a finite-element discretization of the base cell. The optimization problem is solved using sequential linear programming. To benchmark the design method we first consider two-phase designs. Our optimal two-phase microstructures are in fine agreement with rigorous bounds and the so-called Vigdergauz microstructures that realize the bounds. For three phases, the optimal microstructures are also compared with new rigorous bounds and again it is shown that the method yields designed materials with thermoelastic properties that are close to the bounds. The three-phase design method is illustrated by designing materials having maximum directional thermal expansion (thermal actuators), zero isotropic thermal expansion, and negative isotropic thermal expansion. It is shown that materials with effective negative thermal expansion coefficients can be obtained by mixing two phases with positive thermal expansion coefficients and void. (C) 1997 Elsevier Science Ltd.

关键词： microstructures thermomechanical processes constitutive behavior numerical algorithms optimization

来源：评论

学校读者我要写书评

暂无评论

Third-order, minimal-parameter solution of the orthogonal matrix differential equation

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1997年第3期20卷 516-521页

作者： Ronen, M Oshman, Y Technion—Israel Institute of Technology Haifa 32000 Israel

The problem of minimal-parameter solution of the orthogonal matrix differential equation is addressed. This well-known equation arises naturally in three-dimensional attitude determination problems (in aircraft and satellite navigation systems), as well as in the square-root solution of the matrix Riccati differential equation. A direct solution of this equation involves n(2) integrations for the elements of the nth-order solution matrix. However, since an orthogonal matrix is determined by only n(n - 1)/2 independent (albeit nonunique) parameters, a much more efficient solution may, conceivably, be obtained by a parametrization of the problem in terms of such parameters. A new, third-order minimal parametrization, which is motivated by the Peano-Baker solution of linear matrix differential equations, is introduced. The parameters and their corresponding differential equation are very simple and natural. The proposed method is used to provide a new derivation of a closed-form third-order quaternion propagation algorithm, which is commonly used in strapdown inertial navigation systems utilizing rate-integrating gyros. A numerical example is used to demonstrate the viability and high efficiency of the new algorithm.

关键词： Differential Equations Quaternions Strapdown Inertial Navigation System Satellite Navigation Systems Euler Angles Runge Kutta Integration Integration Algorithm Riccati Equations FORTRAN numerical algorithms

来源：评论

学校读者我要写书评

暂无评论

Stochastic analysis of the interception of maneuvering antisurface missiles

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1997年第4期20卷 707-714页

作者： Lipman, Y Shinar, J Oshman, Y TECHNION ISRAEL INST TECHNOL FLIGHT CONTROL LABIL-32000 HAIFAISRAEL

The interception of a maneuvering antisurface missile, as in ballistic missile defense and ship defense scenarios, is formulated as an imperfect information, zero-sum, pursuit-evasion game with a state constraint imposed on the evader. Assuming that the perfect information version of the game does not yield a successful result for the defense, the solution of this game is in mixed strategies. The blind antisurface missile is programmed to perform a random maneuver sequence. The guidance law of the interceptor missile includes a bias, which partially compensates for the inability to achieve a satisfactory deterministic outcome and yields a nonzero probability of success. Moreover, the defense system must launch the interceptor missile at a randomly selected initial range from the incoming antisurface missile based on the solution of a game of timing. A new methodology is presented to assess the probability of successful interception as a function of the parameters of the scenario.

关键词： Missiles Guidance Laws Tactical Ballistic Missile Interceptor Missile Probability Density Functions Warheads Interceptor Guidance Antiaircraft Missiles numerical algorithms Antiship Missile

来源：评论

学校读者我要写书评

暂无评论

Describing function analysis in the presence of uncertainty

引用

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1997年第5期20卷 956-961页

作者： Tierno, JE Honeywell Technology Center Minneapolis MN

A framework is proposed that generalizes describing function (DF) analysis to uncertain systems. By fitting a rational approximation to the DF of nonlinear elements, DF analysis is incorporated into a generalized mu framework of robustness analysis. This allows us to consider uncertainty in both the linear and nonlinear components. Information on the size, frequency, and stability of unforced limit cycles is obtained as in the graphical test. The response to sinusoidal driving inputs can also be analyzed in this framework.

关键词： Single Input Single Output Nonlinear Feedback Nonlinear Systems Frequency Domain numerical algorithms Robust Control Computing MATLAB

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：