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AIAA SciTech Forum

作者： Fukui, Toshiki Takahashi, Masaki Otsuki, Masatsugu Keio Univ Sch Sci Open & Environm Syst 3-14-1 HiyoshiKohoku Ku Yokohama Kanagawa 2238522 Japan Keio Univ Dept Syst Design Engn 3-14-1 HiyoshiKohoku Ku Yokohama Kanagawa 2238522 Japan Japan Aerosp Explorat Agcy Dept Spacecraft Engn Inst Space & Astronaut Sci Sagamihara Kanagawa 2525210 Japan

ISBN: (数字)9781624107115

ISBN: (纸本)9781624107115

In recent years, some countries have embarked on missions to the Moon and Mars to explore the possibility of life and to expand the range of human activities. Simultaneously, several missions are being planned to land on celestial bodies with microgravity and return samples back to Earth. There are two unique challenges in landing and staying on a celestial body with microgravity. The first is that the restoring force due to gravity is small and difficult to balance. Especially, when landing on a slope, there is a risk of large rebound, making it difficult to continue the mission. The second is that the actuator (thruster) can only thrust upward when landing to prevent regolith from scattering. This constraint makes pinpoint landings difficult, because control begins after the rebound and horizontal motion can no longer be controlled independently. To solve this problem, this paper proposes a guidance and control system that enables safe and pinpoint landing. The first step is to model the lander that can represent rebound by explicitly considering the ground. Next, landing reference trajectory design and optimal reference trajectory selection are performed using an optimization algorithm. Finally, the desired control is achieved by tracking the reference trajectory using nonlinear model predictive control while considering actuator constraints. The effectiveness of the proposed method was verified through numerical analysis using a simulator created with MATLAB Simscape Multibody.

关键词： Control System Design Microgravity Actuators Nonlinear Model Predictive Control Earth sequential quadratic programming Phobos MATLAB Collocation Method Trajectory Design

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Optimum Seismic Response Control of Multiple Degree of Freedom Structures using Tuned Viscous Mass Dampers

Optimum Seismic Response Control of Multiple Degree of Freed...

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10th International Conference on Computational Structures Technology

作者： Ikago, K. Sugimura, Y. Saito, K. Inoue, N. Tohoku Univ Grad Sch Engn Sendai Miyagi Japan NTT Facil Inc Res & Dev Tokyo Japan NTT Facil Inc Bldg Engn Tokyo Japan

ISBN: (纸本)9781905088386

The authors have presented a new seismic control device the Tuned Viscous Mass Damper (TVMD). The TVMD consists of a viscous mass damper with an apparent mass amplifier and a soft spring which connects the damper to the primary system. The mass amplifier allowed us to make the additional mass and device itself smaller compared with a conventional TMD. The design method to determine an optimum set of damper parameters has not yet been presented for a vibration control system of a damped MDOF structure, while that of an undamped SDOF structure is obtained by the fixed point theory. In this paper, we present a design method to obtain a set of optimum damper parameters for a seismic control system of a damped MDOF structure using sequential quadratic programming (SQP).

关键词： tuned viscous mass damper dynamic vibration absorber optimum vibration control fixed point theory sequential quadratic programming seismic control

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Newton-type methods for constrained optimization with nonregular constraints

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Computational Mathematics and Mathematical Physics 2006年第8期46卷 1299-1319页

作者： Golishnikov, M.M. Izmailov, A.F. Faculty of Computational Mathematics and Cybernetics Moscow State University Leninskie gory Moscow 119992 Russian Federation

The most important classes of Newton-type methods for solving constrained optimization problems are discussed. These are the sequential quadratic programming methods, active set methods, and semismooth Newton methods for Karush-Kuhn-Tucker systems. The emphasis is placed on the behavior of these methods and their special modifications in the case where assumptions concerning constraint qualifications are relaxed or altogether dropped. Applications to optimization problems with complementarity constraints are examined. © MAIK "Nauka/Interperiodica".

关键词： Active set methods Constrained optimization problems Constraint qualifications Newton-type methods Semismooth Newton methods sequential quadratic programming

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Predictive velocity control in a hilly terrain over a long look-ahead horizon 5

Predictive velocity control in a hilly terrain over a long l...

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5th International-Federation-of-Automatic-Control (IFAC) Conference on Engine and Powertrain Control, Simulation and Modeling (E-COSM)

作者： Hamednia, Ahad Murgovski, Nikolce Fredriksson, Jonas Chalmers Univ Technol Dept Elect Engn S-41296 Gothenburg Sweden

This paper presents a computationally efficient velocity control of vehicles driving in a possibly hilly terrain and over long look-ahead horizons that may stretch to hundreds of kilometers. The controller decouples gear scheduling into an offline optimization problem, from the remaining optimization problem that governs two real-valued states. One of the states, the travel time, is adjoined to the objective by applying the necessary optimality conditions, which results into an online optimization problem that has kinetic energy as the single state. Finally an inner approximation is proposed for the online problem to obtain a quadratic program that can be solved efficiently. The efficiency of the proposed controller is shown for different horizon lengths. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

关键词： Predictive control Cruise control Offline gear scheduling sequential quadratic programming

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A high-order partitioned solver for general multiphysics problems and its applications in optimization

A high-order partitioned solver for general multiphysics pro...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Huang, Daniel Z. Persson, Per-Olof Zahr, Matthew J. Stanford Univ Inst Computat & Math Engn Durand Bldg Room 226 Stanford CA 94305 USA Univ Calif Berkeley Dept Math Berkeley CA 94720 USA Univ Notre Dame Dept Aerosp & Mech Engn Notre Dame IN 46556 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

A high-order accurate adjoint-based optimization framework is presented for unsteady multiphysics problems. The fully discrete adjoint solver relies on the high-order, linearly stable, partitioned solver introduced in [1], where different subsystems are modeled and discretized separately. The coupled system of semi-discretized ordinary differential equations is taken as a monolithic system and partitioned using an implicit-explicit Runge-Kutta (IMEX-RK) discretization[2]. Quantities of interest (QoI) that take the form of space-time integrals are discretized in a solver-consistent manner. The corresponding adjoint equations are derived to compute exact gradients of QoI, which can be solved in a partitioned manner, i.e. subsystem-by-subsystem and substage-by-substage, thanks to the partitioned primal solver. These quantities of interest and their gradients are then used in the context of gradient-based PDE-constrained optimization. The present optimization framework is applied for a 1D fluid-structure-mesh 3-field coupling piston problem and a 2D fluid-structure 2-field coupling foil energy harvesting problem.

关键词： Energy Harvesting Fluid Structure Interaction Finite Volume Method Compressible Fluid Vorticity Discontinuous Galerkin Method Mathematical Models Gas Constant Fluid State sequential quadratic programming

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Computational Modeling of Flutter Constraint for High-Fidelity Aerostructural Optimization

Computational Modeling of Flutter Constraint for High-Fideli...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Jonsson, Eirikur Mader, Charles A. Martins, Joaquim R. R. A. Kennedy, Graeme J. Univ Michigan Ann Arbor MI 48109 USA Georgia Inst Technol Sch Aerosp Engn Atlanta GA 30332 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

High fidelity computational modeling and optimization of aircraft has the potential to allow engineers to produce more efficient designs, requiring fewer unforeseen design modifications late in the design process. In order for the optimization algorithm to generate a useful design, all the relevant physics must be considered, including flutter. This is especially important for the high-fidelity aerostructural optimization of commercial aircraft, which is likely to result in wing designs that are prone to flutter. To address this issue, we develop a flutter constraint formulation suitable for gradient-based optimization. This paper investigates the feasibility of using a Doublet-Lattice Method (DLM) based flutter constraint for high-fidelity aerostructural optimization. An efficient non-iterative root finding method is developed to compute the flutter eigenvalues from a generalized eigenvalue problem, based on the p-k flutter equation. A mode tracking scheme is implemented at two levels that successfully tracks the mode migration. An effective constraint curve is then developed to define the flutter free flight envelope, in addition to preventing discontinuities in the flutter constraint. This method allows for minimum flutter velocity to be specified implicitly. The Kreisselmeier-Steinhauser (KS) function is used to aggregate the difference of the flutter damping eigenvalues and the constraint curve into a single value that is then used in an optimization. We compute accurate and efficient derivatives of the constraint value with respect to structural sizing variables, as well as wing planform variables. Derivatives are computed using a combination of analytic and automatic differentiation methods in reverse (adjoint) and validated using the complex-step method. To study the behavior of the flutter constraint using this method, we perform a design space analysis and optimize an idealized wing (flat plate) of a rectangular planform.

关键词： High Aspect Ratio Lift to Drag Ratio sequential quadratic programming Commercial Aircraft Structural Damping Aerodynamic Damping Dynamic Pressure Finite Element Analysis Nastran Sparse Nonlinear Optimizer

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Multi-Fidelity Wing Optimization Utilizing 2D to 3D Pressure Distribution Mapping in Transonic Conditions

Multi-Fidelity Wing Optimization Utilizing 2D to 3D Pressure...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： MacDonald, Timothy Alonso, Juan J. Stanford Univ Dept Aeronaut & Astronaut Stanford CA 94305 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

Due to time and resource constraints, the conceptual design process for new aircraft is typically limited to inexpensive low-fidelity methods. Unfortunately, these methods generally only provide the fidelity necessary to confidently go forward with a new design when they have been calibrated to previous aircraft of similar type. This substantially limits the application of new technology early in the design cycle, and means that only high-level information can be obtained, potentially limiting the available design space. To remedy this, new methods must be developed that can produce higher-fidelity results without a significant increase in cost. Here, we demonstrate a method for higher-fidelity aerodynamic analysis that incorporates 2D and 3D pressure distribution mapping into a multi-fidelity framework. This expands on previous work in the area by providing a multi-fidelity approach that allows for the prediction of the shape of the pressure distribution in addition to high level aerodynamic performance. As part of this demonstration, we present results for a wing that has been optimized using the 3D solver FLO107 exclusively, as well as a combination of the 2D solver FLO103 and FLO107. The differences in required evaluations and the final results are documented.

关键词： Aerodynamic Performance Skin Friction Aerodynamic Shape Optimization Supercritical Airfoils Linear Interpolation Transonic Flow sequential quadratic programming Thickness to Chord Ratio Shape Optimization Swept Wing

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Aerodynamic Shape Optimization for Natural Laminar Flow Using a Discrete-Adjoint Approach 22

Aerodynamic Shape Optimization for Natural Laminar Flow Usin...

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22nd AIAA Computational Fluid Dynamics Conference

作者： Rashad, Ramy Zingg, David W. Univ Toronto Toronto ON M3H 5T6 Canada

ISBN: (数字)9781624103667

ISBN: (纸本)9781624103667

A framework for the design of natural-laminar-flow airfoils is developed based on multipoint aerodynamic shape optimization capable of efficiently incorporating and exploiting laminar-turbulent transition. A two-dimensional Reynolds-averaged Navier-Stokes flow solver making use of the Spalart-Allmaras turbulence model is extended to incorporate an iterative laminar-turbulent transition prediction methodology. The natural transition locations due to Tollmien-Schlichting instabilities are predicted using a simplified e(N) method or the compressible form of the Arnal-Habiballah-Delcourt criterion. The Reynolds-averaged Navier-Stokes solver is subsequently used in a gradient-based sequential quadratic programming shape optimization framework. The transition criteria are tightly coupled into the objective and gradient evaluations. The gradients are obtained using an augmented discrete-adjoint formulation for nonlocal transition criteria. Robust design over a range of cruise flight conditions is demonstrated through multipoint optimization. Finally, a technique is proposed and demonstrated to enable the design of natural-laminar-flow airfoils with robust performance over a range of critical N factors: the optimizer is seen to produce transition ramps similar to those used by experienced designers.

关键词： Natural Laminar Flow Aerodynamic Shape Optimization Reynolds Averaged Navier Stokes Laminar Turbulent Transition sequential quadratic programming Spalart Allmaras Turbulence Model Shape Optimization Aerodynamic Performance Commercial Aircraft Lift to Drag Ratio

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Dynamic data reconciliation based on an improved robust M-estimator

Dynamic data reconciliation based on an improved robust M-es...

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Chinese Automation Congress (CAC)

作者： Zhang, Yu Wang, Xiaoli Cent South Univ Sch Informat Sci & Engn Changsha 410083 Hunan Peoples R China

ISBN: (纸本)9781728113128

In order to increase the stability and accuracy of the dynamic data reconciliation, this paper proposes a new piecewise robust estimation function as the objective function of dynamic data reconciliation, it combines the advantages of robust M-estimator and least squares estimator. This function corrects the random error and gross error with different weights, and enhances the stability and accuracy of the reconciled results. The performance of the robust new objective function is proved by CSTR simulation. In order to further improve the performance, a robust dynamic data reconciliation method combining the improved particle swarm optimization and sequential quadratic programming is proposed for constrained nonlinear optimization problems. The simulation results show that the method can reduce fluctuation of the reconciled value which is closer to the true value.

关键词： dynamic data reconciliation robust estimator particle swarm optimization sequential quadratic programming

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A Post-Flutter Response Constraint for Gradient-Based Aircraft Design Optimization

A Post-Flutter Response Constraint for Gradient-Based Aircra...

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AIAA Aviation Forum and Exposition

作者： Riso, Cristina Cesnik, Carlos E. S. Epureanu, Bogdan, I Teufel, Patrick Univ Michigan Dept Aerosp Engn 1320 Beal Ave Ann Arbor MI 48109 USA Univ Michigan Dept Mech Engn 2350 Hayward St Ann Arbor MI 48109 USA Airbus Operat GmbH Blagnac France

ISBN: (数字)9781624106101

ISBN: (纸本)9781624106101

Considering flutter as a constraint in aircraft design optimization has the potential to enable energy-efficient vehicle designs with high-aspect-ratio wings while meeting flutter requirements early in the design cycle. However, nonlinear aeroelastic effects in high-aspect-ratio wings may cause self-sustained oscillations to arise even before flutter occurs (subcritical bifurcation). To address this problem, this paper presents a novel post-flutter response constraint for gradientbased aircraft design optimization. The constraint prevents self-sustained oscillations inside the flight envelope independent of the flutter boundary. Moreover, it avoids transient or iterative calculations and can handle discontinuities due to mode switches and hump modes. The formulation is demonstrated by optimizing a typical aeroelastic section with a nonlinear torsion spring and an initially subcritical bifurcation. The results show that the post-flutter response constraint suppresses the subcritical bifurcation while keeping the flutter constraint active, so avoiding a conservative solution.

关键词： Aircraft Design High Aspect Ratio Flight Envelope Transient Response Nonlinear Aeroelastic Systems Computing Stiffness Matrices Structural Damping Aerodynamic Shape Optimization sequential quadratic programming

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