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MODE TRACKING ISSUES IN STRUCTURAL optimization

AIAA JOURNAL 1995年第10期33卷 1926-1933页

作者： ELDRED, MS VENKAYYA, VB ANDERSON, WJ UNIV MICHIGAN ANN ARBORMI 48109 USA AEROFLIGHTDYNAM DIRECTORATEWRIGHT PATTERSON AFBOH 45433

Within the context of optimization of the structural dynamics properties of finite element models, methodology is developed for the tracking of eigenpairs through changes in the structural eigenvalue problem. The goal is to eliminate difficulties caused by ''mode switching'' (i.e., frequency crossing), Out of several candidate methods, two methods for mode tracking are successful. The first method, the higher order eigenpair perturbation algorithm, is based on a perturbation expansion of the eigenproblem. It iteratively computes changes in the eigenpairs due to parameter perturbations with the important feature of maintaining the correspondence between the baseline and perturbed eigenpairs. The second method is a cross-orthogonality check method, which uses mass orthogonality to reestablish correspondence after a standard reanalysis. Modified eigenpair extraction routines (Lanezos, subspace iteration, inverse power) were unsuccessful in tracking modes. Applications of mode tracking technology that are presented are frequency-constrained optimization and optimization with mode shape constraints. Each application procedure is outlined and examples are given. Recommendations are made based on method efficiency and robustness in the example problems.

关键词： Structural optimization Finite Element Modeling Structural Dynamics Wing Box Nonlinear Programming Free Vibrations Singular Value Decomposition Aeroelastic Analysis Track algorithm optimization algorithm

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MISSILE SIZING FOR ASCENT-PHASE INTERCEPT

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JOURNAL OF SPACECRAFT AND ROCKETS 1995年第3期32卷 445-449页

作者： HULL, DG SALGUERO, DE SANDIA NATL LABS CTR AEROSP SYST DEVTECH STAFFALBUQUERQUENM 87185

A computer code has been developed to determine the size of a ground-launched, multistage missile that can intercept a theater ballistic missile before it leaves the atmosphere. Typical final conditions for the interceptor are 450-km range, 60-km altitude, and 80-s flight time. Given the payload mass, which includes a kinetic kill vehicle, and achievable values for the stage mass fractions, the stage specific impulses, and the vehicle density, the launch mass is minimized with respect to the stage payload mass ratios, the stage burn times, and the missile angle-of-attack history subject to limits on the angle of attack, the dynamic pressure, and the maneuver toad. For a conical body, the minimum launch mass is approximately 1900 kg. The missile has three stages, and the payload coasts for 57 s. A trade study is performed by varying the flight time, the range, and the dynamic pressure limits. A more detailed design is carried out for a particular missile to determine the heat-shield mass. The added heat-shield mass reduces the prescribed range by 100 km. Air-launching the same missile increases its range by 100 km. Finally, sizing the intercepter for air launch reduces its mass to approximately 1000 kg.

关键词： Air Launch Lift Coefficient Dynamic Pressure Heat Shield Short Range Ballistic Missile Aerodynamic Stability Nonlinear Programming optimization algorithm Mass Flow Rate Propellant

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GENETIC-algorithm-BASED PROCEDURE FOR PRETEST ANALYSIS

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AIAA JOURNAL 1995年第7期33卷 1362-1364页

作者： FRANCHI, CG GALLIENI, D Politecnico di Milano Milan 20133 Italy

The features of genetic algorithm and their major advantages with respect to other analytical, heuristic, or stochastic optimization methods are pointed out. The algorithm is applied to solve a problem and has been proved to fulfill its properties: the optimal placement of sensors in pretest analysis. A proper objective function is defined to include both the requests of observability of the reduced system and of geometrical reconstruction of the measured mode shapes. The results, although obtained from simple examples, confirm all of the premises and are in accordance with physical experience.

关键词： Genetic algorithm Finite Element Modeling Modal Analysis Cantilever Annealing Computing Boundary Value Problems Stochastic optimization optimization algorithm Structural Dynamics

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OPTIMAL PLACEMENT OF DAMPED STRUTS USING SIMULATED ANNEALING

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JOURNAL OF SPACECRAFT AND ROCKETS 1995年第4期32卷 653-661页

作者： HAMERNIK, TA GARCIA, E STECH, D VANDERBILT UNIV DEPT MECH ENGNSMART STRUCT LABNASHVILLETN 37235 USAF ACAD FRANK J SEILER RES LABCOLORADO SPRINGSCO 80840

Presented is the optimization of the placement of damped structural elements in a two-dimensional truss network. This work presents a modification of a heuristic optimization technique called simulated annealing, to improve the speed of convergence. Rather than setting the annealing temperature schedule a priori, it is modified according to the change in cost functional. For a single mode of vibration, a comparison is made between the simulated-annealing results and the true optimal locations, as determined by the modal strain locations. As expected, simulated annealing returns a near-optimal solution from a variety of initial configurations. Modal weighting factors are utilized to examine multiple modes, and again the modal strain locations are used for comparison.

关键词： Annealing Temperature Planar Truss Structural Response Vibration Suppression Finite Element Analysis optimization algorithm Structural System Ball Bearings Frequency Response Functions Adaptive Structures

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OPTIMAL SOLUTION OF VEHICLE-ROUTING PROBLEMS USING MINIMUM K-TREES

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OPERATIONS RESEARCH 1994年第4期42卷 626-642页

作者： FISHER, ML UNIV PENN PHILADELPHIA PA 19104 USA

We consider the problem of optimally scheduling a fleet of K vehicles to make deliveries to n customers subject to vehicle capacity constraints. Given a graph with n + 1 nodes, a K-tree is defined to be a set of n + K edges that span the graph. We show that the vehicle routing problem can be modeled as the problem of finding a minimum cost K-tree with two K edges incident on the depot and subject to some side constraints that impose vehicle capacity and the requirement that each customer be visited exactly once. The side constraints are dualized to obtain a Lagrangian problem that provides lower bounds in a branch-and-bound algorithm. This algorithm has produced proven optimal solutions for a number of difficult problems, including a well-known problem with 100 customers and several real problems with 25-71 customers.

关键词： programming integer algorithms relaxation/subgradient: k-tree based transportation vehicle routing optimization algorithm

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ENGINEERING CODE FOR HYPERSONIC VEHICLE optimization

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JOURNAL OF SPACECRAFT AND ROCKETS 1994年第1期31卷 150-152页

作者： THOMPSON, RA RILEY, CJ NASA Langley Research Center Hampton Virginia 23681

optimization of complex systems, such as aerospace vehicles, crosses many disciplinary boundaries and is still a relatively new field of engineering research. Although full multidisciplinary optimization of these systems is the ultimate goal and progress toward these ends has been made1.2, optimization within a single discipline remains an important component. Development of optimization techniques in fields such as structural mechanics and design has been well published3,4, but examples of aerodynamic optimization have been less visible.

关键词： Hypersonic Vehicles Freestream Conditions Boundary Layer Equations Aerothermodynamic optimization Stagnation Region Perfect Gas Shock Layers Hypersonic Flows optimization algorithm Wind Tunnels

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TRAJECTORY optimization-BASED ON DIFFERENTIAL INCLUSION

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 1994年第3期17卷 480-487页

作者： SEYWALD, H Analytical Mechanics Associates Inc. Hampton Virginia 23666

A method for generating finite-dimensional approximations to the solutions of optimal control problems is introduced. By employing a description of the dynamical system in terms of its attainable sets in favor of using differential equations, the controls are completely eliminated from the system model. Besides reducing the dimensionality of the discretized problem compared to state-of-the-art collocation methods, this approach also alleviates the search for initial guesses from where standard gradient search methods are able to converge. The mechanics of the new method are illustrated on a simple double integrator problem. The performance of the new algorithm is demonstrated on a one-dimensional rocket ascent problem (Goddard Problem) in presence of a dynamic pressure constraint.

关键词： Trajectory optimization Dynamic Pressure Sounding Rockets Goddard Problem Collocation Method Nonlinear Programming Aerodynamic Drag Boundary Value Problems optimization algorithm Describing Function

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APPROXIMATION IN NONHIERARCHIC SYSTEM optimization

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AIAA JOURNAL 1994年第1期32卷 198-205页

作者： RENAUD, JE GABRIELE, GA RENSSELAER POLYTECH INST DEPT MECH ENGN AERONAUT ENGN & MECHTROYNY 12180

This paper reports on the effectiveness of a nonhierarchic systema* optimization algorithm in application to complex coupled systems problems. A second-order nonhierarchic systema* optimization algorithm developed in earlier studies is modified in this study to provide for individual constraint/state modeling. A cumulative constraint formulation was used in previous implementation studies. The test problems in this study are each complex coupled systems. Complex coupled systems require an iterative solution strategy to evaluate system states. Nonhierarchic algorithm development is driven by these types of problems, and their study is imperative. The algorithm successfully optimizes each of the complex coupled systems. A significant reduction in the number of system analyses required for optimization is observed as compared with conventional optimization using the generalized reduced-gradient method.

关键词： Iterative Solution algorithms and Applications optimization algorithm Gradient Method Heat Sinks Multidisciplinary Design optimization Electronic Component Thermal Analysis Artificial Neural Network Nonlinear Programming

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Teleoperation and Robotics in Space

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丛书名： Progress in Astronautics and Aeronautics

1994年

作者： Steven B. Skaar Carl F. Ruoff

ISBN: (数字)9781600866333

ISBN: (纸本)9781563470950

Increasingly, space teleoperators and robots (space telerobots) will take the place of astronauts in planetary and lunar scientific missions to reduce cost and risk. Terrestrial robots have much in common with space robots, but there are important physical differences arising from weightlessness, vacuum, the thermal environment, and the need to minimize mass. Because the technology for building intelligent space robots does not yet exist, they must be supervised by human operators. This book addresses these concerns, providing extensive, well-illustrated descriptions of existing, planned, and laboratory space telerobot systems, international designs, the role and capabilities of humans in system control and supervision, levels of control autonomy, the economic trade-offs of manned versus telerobotic space operations, and dynamics and control. The book provides engineers, scientists, managers, policy makers, and students with the underlying technical issues associated with human-supervised space robots and the design, justification, and use of practical space telerobot systems.

关键词： algorithms and Data Structures Applied Mathematics Artificial Intelligence Autonomous Systems Avionics Computers Avionics Software Classical Mechanics Communication System Communication Technology and Equipment Communications Satellite Computer Graphics Computer Networks Computer Programming and Language Computer Vision Computing Environments Computing System Computing and Informatics Computing, Information, and Communication Control Systems Control Theory Crewed Spacecrafts Data Science Feedback Control Flight Computer General Physics Geometry Functions Guidance, Navigation, and Control Systems Human Spaceflight ISS Module Interdisciplinary Topics International Space Station Launch Vehicles Life Support System Manipulators Operating Systems optimization algorithm Research Facilities and Instrumentation Robot Control Robot Dynamics Robot Kinematics Robotic Sensing Robotics Robotics Systems Robots Satellites Signal Processing Software Systems Space Launch Systems Space Manipulator Space Science and Technology Space Shuttle Space Shuttle Orbiter Space Stations Space Systems Space Systems and Vehicles Space Vehicle Space Vehicle Control Spacecraft Components Spacecraft Design Spacecraft Docking Spacecraft System Spacecrafts Spaceflight Systems Software Telemetry Uncrewed Spacecraft

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ON FAULT-DIAGNOSIS OF ANALOG CIRCUITS WITH TOLERANCE USING SIMULATED ANNEALINGa* optimization algorithm

ON FAULT-DIAGNOSIS OF ANALOG CIRCUITS WITH TOLERANCE USING S...

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INTERNATIONAL CONF ON INDUSTRIAL ELECTRONICS, CONTROL, INSTRUMENTATION, AND AUTOMATION ( IECON 92 )

作者： LI, Y WENG, XY Northwestern Polytechnical University Xi'an China

ISBN: (纸本)0780305825

The authors extend the numerical annealing algorithm framework presented by S. Kirkpatrick et al. to the case of continuous multidimensional parameter space. The design an efficient parameter inverse simulated annealing (PI-SA) algorithm, and obtain some important theoretical results on continuous annealing algorithm design. They apply the PI-Sa* optimization algorithm to fault diagnosis of analog circuits with tolerance. A software package for automatic diagnosis has been developed and applied to fault isolation of the electronic equipment of the remotely piloted vehicles. The diagnosis results obtained with the software package both ground simulation and in flight testing are satisfactory.

关键词： fault location aerospace testing automatic testing fault diagnosis analog circuits tolerance simulated annealing optimization algorithm continuous multidimensional parameter space design parameter inverse software package fault isolation ground simulation in flight testing aerospace testing analogue circuits automatic testing fault location integrated circuit testing simulated annealing

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