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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Wan, Changhuang Jing, Gangshan Dai, Ran Rea, Jeremy R. Ohio State Univ Mech & Aerosp Engn Dept Columbus OH 43210 USA NASA Johnson Space Ctr Flight Mech & Trajectory Design Branch 2001 Nasa Pkwy EG5 Houston TX 77058 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

This paper investigates the fuel-optimal guidance problem of the end-to-end human-Mars entry, powered descent, and landing (EDL) mission. It proposes a computationally efficient modeling scheme and a new optimization algorithm to solve the multi-phase optimal guidance problem. We first model the end-to-end EDL guidance problem as a multi-phase optimal control problem with different dynamics and constraints at each phase. Via polynomial approximation and discretization techniques, this multi-phase optimal control problem is then reformulated as a polynomial programming problem. By introducing intermediate variables and quadratic equality constraints, a polynomial program is equivalently converted into a nonconvex quadratically constrained quadratic program (QCQP). To efficiently solve the large scale QCQPs, a customized alternating direction method of multipliers (ADMM) is designed to search a local optimum. The fuel savings under the end-to-end human-Mars EDL guidance is verified by comparing to the fuel consumption amount using the separate phase guidance approach. Furthermore, the computational efficiency of the customized ADMM algorithm is validated by comparing to the state-of-art nonlinear programming method.

关键词： Fuels Numerical Optimization Bang Bang Control Fuel Consumption sequential quadratic programming Dynamic Pressure Flight Path Angle Aerodynamic Force Hypersonic Inflatable Aerodynamic Decelerator Lagrange Multipliers

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Uncertainty Analysis of Trajectory Tracking for Autonomous Dynamic Soaring

Uncertainty Analysis of Trajectory Tracking for Autonomous D...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： He, Kaijun Wang, Jiachen Gorodetsky, Alex A. Univ Michigan Dept Mech Engn Ann Arbor MI 48109 USA Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

We quantify the effect of mis-modeled wind conditions on planned and executed energy-neutral trajectories for autonomous dynamic gliding aircraft with a sampling-based probabilistic assessment. Our conclusions indicate the need for future approaches to incorporate model-form error of the wind dynamics into adaptive and/or feedback controllers. While previous works have either analyzed the uncertainty in open-loop controllers developed through either deterministic or stochastic (robust) optimization, our analysis considers the performance of closed-loop (reference-tracking) controllers in the context of both parameter and model-form errors. These controllers use a forward-looking model predictive controller to track a trajectory that was optimized for a deterministic wind profile. The performance of the glider was then simulated using different deterministic wind profiles and gust conditions. The total air-relative energy and glider displacement were then measured for each wind realization to determine the effect of wind field uncertainty on performance. We conclude that the closed-loop controller can efficiently improve the trajectory tracking performance if the deterministic wind profile is not very different from the predicted wind model. However, the closed-loop performance under significant difference in the model form of the wind profile was far from optimal. We find that mis-modelling the underlying deterministic wind profile causes up to 30% loss in energy, significantly more than any effects due to gust.

关键词： Dynamic Soaring Model Predictive Control Drag Coefficient Turbulence Intensity Flight Path Angle Turbulence Models Power Spectral Density Lift to Drag Ratio Heading Angle sequential quadratic programming

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Perspectives on Aerodynamic Design Optimization

Perspectives on Aerodynamic Design Optimization

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Martins, Joaquim R. R. A. Univ Michigan Dept Aerosp Engn Ann Arbor MI 48109 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

CFD-based aircraft design optimization has matured significantly in the last few years thanks to improvements in CFD solvers, mesh deformation, sensitivity computation, and optimization tools. We review our recent developments for each of these components, and present open-source tools made available for aerodynamic shape optimization. Avariety of applications is presented, including the optimization of a supercritical airfoil starting from a circle, a web application that optimizes airfoils within a few seconds, aircraft aerodynamic and aerostructural optimization, and aeropropulsive optimization. We also review our experience with solving the Aerodynamic Design Optimization Discussion Group (ADODG) benchmarks and other problems in aerodynamic shape optimization. Among the ADODG benchmarks, we focus on the RANS-based problems and discuss some of the issues encountered, including the comparison between Euler and RANS results, and design space multimodality. The availability of these benchmarks and the open-source tools is expected to enable further studies and benchmarks in CFD-based aerodynamic design optimization and MDO.

关键词： Aerodynamic Force Coefficients Multidisciplinary Design Optimization Aircraft Design Supercritical Airfoils Lift Coefficient Aircraft Configurations sequential quadratic programming Shape Optimization FORTRAN Gradient Free Optimization

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Shape Optimization of Vortex Generators to Control Mack Mode Amplification

Shape Optimization of Vortex Generators to Control Mack Mode...

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AIAA Aviation Forum

作者： Pederson, Clark C. Choudhari, Meelan M. Zhou, Beckett Y. Parede, Pedro Disking, Boris Univ Texas Austin Walker Dept Mech Engn Austin TX 78712 USA NASA Langley Res Ctr Computat AeroSci Branch Hampton VA 23681 USA TU Kaiserslautern Chair Sci Comp Bldg 34Paul Ehrlich Str D-67663 Kaiserslautern Germany NIA Computat AeroSci Branch Hampton VA 23681 USA NIA Hampton VA 23681 USA

ISBN: (数字)9781624105982

ISBN: (纸本)9781624105982

This paper demonstrates the potential to use shape optimization for the design of vortex generators in an axisymmetric boundary layer. This shape optimization increases the amplitude of stationary streaks created by streamwise vorticity, with the goal of reducing the amplification of Mack mode instabilities. The test case under consideration matches a trajectory point during the ascent phase of the HIFiRE-1 flight experiment. Wall-mounted vortex generators are added to the cone and their shape is optimized to control the amplification of Mack mode instabilities that are known to initiate laminar-turbulent transition in this flow. An empirical objective function is developed based on the previous studies of optimal streaks. A constraint on the maximum streak amplitude is added to avoid the initiation of bypass transition. The shape optimization is conducted using SU2, an open-source suite for multiphysics simulation and design. A significant improvement is observed in an integral metric of the streak amplitude, while the maximum streak amplitude is maintained close to the baseline level. The qualitative features of the optimized geometry are discussed.

关键词： Vortex Generators Shape Optimization Laminar Turbulent Transition Tollmien Schlichting waves Direct Numerical Simulation Freestream Mach Number sequential quadratic programming Hypersonic Flows Navier Stokes Equations Lagrange Multipliers

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Objectives and Constraints for Transonic Wing Optimization

Objectives and Constraints for Transonic Wing Optimization

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Poole, D. J. Allen, C. B. Rendall, T. C. S. Univ Bristol Dept Aerosp Engn Bristol BS8 1TR Avon England Univ Bristol Dept Aerosp Engn Computat Aerodynam Bristol BS8 1TR Avon England

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

Consideration of the aerodynamic shape optimization problem definition is presented. An issue with drag minimization is that shocked-free solutions often result which have isolated performance improvements. As such, in this paper, optimizing the range parameter is considered enriched with the operating point as a design variable. A constraint on dimensional lift is therefore required. Analytical treatment of this problem is used to demonstrate that supercritical solutions result providing the lift is above a critical threshold. Also, three-dimensional effects penalise lift coefficient and promote higher optimum Mach numbers. Single- and multi-point optimizations of the NASA CRM wing are considered, inspired by the AIAA ADODG Case 4, as well as a range optimization. A shocked solution is found for the range optimization.

关键词： Aerodynamic Shape Optimization Lift Coefficient Multi Point Optimization Reynolds Averaged Navier Stokes sequential quadratic programming Transonic Flow Aspect Ratio Wing Loading Computational Fluid Dynamics Aircraft Design

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Direct numerical solution of a time-optimal state-constrained control problem in a flow 7

Direct numerical solution of a time-optimal state-constraine...

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7th International Conference on Control, Decision and Information Technologies (CoDIT)

作者： Chertovskih, Roman Pereira, Fernando Lobo Univ Porto Fac Engn Res Ctr Syst & Technol SYSTEC Elect & Comp Engn Dept Porto Portugal

ISBN: (纸本)9781728159539

We consider the following time-optimal control problem with state constraints: compute minimal travelling time of a controllable object moving in a prescribed flow field in a bounded domain between two given points. The optimal control problem is solved numerically using two direct methods interior-point line search filter method and sequential quadratic programming. Five sample flows are considered, and computational properties of the corresponding simulations are measured and discussed.

关键词： optimal control direct methods interior-point method sequential quadratic programming

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Nonlinear Model Predictive Control and Collision-Cone-Based Missile Guidance Algorithm

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2021年第8期44卷 1481-1497页

作者： Bhattacharjee, Diganta Chakravarthy, Animesh Subbarao, Kamesh Univ Texas Arlington Dept Mech & Aerosp Engn Box 19018 Arlington TX 76019 USA

In this paper, a hybrid missile guidance algorithm is proposed for planar engagement scenarios. The method combines nonlinear model predictive control (NMPC) with a collision cone approach, and enables the guidance algorithm to achieve interception, while ensuring that the impact angle lies in a predefined range. The guidance scheme comprises two components: 1) point-mass-based NMPC and 2) collision-cone-based NMPC. The point-mass-based NMPC is employed when the distance between the missile and the target is large, and when this distance falls below a threshold, the algorithm switches to a collision-cone-based NMPC. Connections between the impact angle and the collision cone are theoretically established, and these are used in the collision-cone-based NMPC. The NMPC problems are formulated as quadratic programs that include appropriate constraints on the states and inputs, while not requiring target acceleration information. These quadratic programs are shown to be strictly convex. Detailed simulations are performed to demonstrate the effectiveness of the proposed approach.

关键词： Guidance Algorithms Model Predictive Control sequential quadratic programming Terminal Guidance Control Guidance Heading Angle Optimal Control Engagement Kinematics Warheads Convex Optimization

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Parameter Identification for a 3D Heating Process by the Adjoint Method based on Experimental Data

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IFAC-PapersOnLine 2021年第11期54卷 103-108页

作者： Dirk Wolfram Thomas Meurer Chair of Automatic Control Faculty of Engineering Kiel University 24143 Kiel Germany

Model-based control of systems governed by partial differential equations relies on the knowledge of the model parameters. Their determination is complicated by the spatial-temporal process dynamics. In addition the interaction of the process and the (embedded) actuation devices might be subject to uncertainties. This work applies a late-lumping approach for parameter identification given a 3-dimensional heat conduction and heat transfer problem with actuation dynamics represented by a coupled PDE-ODE model. By defining a suitable minimization problem the necessary optimality conditions in terms of adjoint PDE-ODE couplings are determined using variational calculus. In additional gradient information can be directly extracted that is used in course of the numerical evaluation by making use of sequential quadratic programming. For this the Finite-Element method is applied for the forward solution of the model equations and backward solution of the adjoint equations. Data collected at the experimental realization of 3-dimensional heating process for different actuation scenarios is used for evaluation and comparison.

关键词： Parameter identification Heat equation Adjoint Method Actuator dynamics Optimization Finite Element Method Partial Differential Equations sequential quadratic programming

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Aerodynamic Shape Optimization for Unsteady Flows: Some Benchmark Problems

Aerodynamic Shape Optimization for Unsteady Flows: Some Benc...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Apponsah, Kwesi P. Zingg, David W. Univ Toronto Inst Aerosp Studies Toronto ON M3H 5T6 Canada Univ Toronto Inst Aerosp Studies Computat Aerodynam & Sustainable Aviat Toronto ON M3H 5T6 Canada Univ Toronto Inst Aerosp Studies Ctr Res Sustainable Aviat Toronto ON M3H 5T6 Canada Univ Toronto Inst Aerosp Studies Ctr Computat Sci & Engn Toronto ON M3H 5T6 Canada

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

We present an efficient aerodynamic shape optimization framework for optimization problems under unsteady flow conditions. The optimization framework consists of a parallel Newton-Krylov flow solver for multi-block grids and an integrated geometry parameterization and mesh-deformation algorithm based on linear elasticity. We apply the adjoint method to the discretized governing equations to compute the gradients required by the sequential quadratic programming optimization algorithm. We propose two lift-constrained drag minimization problems for the purposes of testing and evaluating the framework. First, we consider a laminar flow airfoil optimization problem at a Reynolds number of 800 and also investigate the convexity of the optimization problem. We show that the optimizer is capable of reducing the drag for this problem by about 23% and produces a nearly steady flow compared to the vortex shedding observed for the baseline geometry at the required lift target. The second benchmark case is a lift-constrained drag minimization of an aspect ratio eight rectangular wing in a laminar flow at a Reynolds number of 800. Section shape, twist, and angle of attack are free. Although only partially converged at the time of writing, the preliminary results show a 20% drag reduction.

关键词： Aerodynamic Shape Optimization Flow Conditions Lift Coefficient Airfoil Vortex Shedding sequential quadratic programming Aspect Ratio Lift to Drag Ratio Linear Elasticity Computational Fluid Dynamics

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Direct Methods Comparison for the Active Target Defense Scenario

Direct Methods Comparison for the Active Target Defense Scen...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Weintraub, Isaac E. Cobb, Richard Baker, William Pachter, Meir US Air Force Res Lab Wright Patterson AFB OH 45433 USA US Air Force Res Lab Dept Aerosp Engn Wright Patterson AFB OH 45433 USA US Air Force Res Lab Dept Mathemat Wright Patterson AFB OH 45433 USA US Air Force Res Lab Dept Elect Engn Wright Patterson AFB OH 45433 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

The goal of optimal control is to obtain an admissible function which minimizes an objective functional subject to specified constraints and boundary conditions. Four popular methods of computing the optimal control directly are the Single Shooting Method, Multiple Shootings Method, Even Collocation Method, and Pseudospectral Method. In this paper, the four direct methods of computing the optimal control for the Active Target Defense Scenario are presented and compared. The Active Target Defense Scenario is a three-agent engagement where an evading agent tries to escape a pursuing agent with the assistance of a defending agent. The goal of the Evader is to maneuver in such a way as to assist the Defender in capturing the Pursuer while maximizing his range from the Pursuer. This work begins by describing each direct method and summarizing advantages and disadvantages of each. Next, each method is used to solve the optimal control for the Active Target Defense Scenario;results are presented and a comparison of the performance of each method is made. Finally, concluding remarks describing the results, performance, and real-time implementation are presented.

关键词： Optimal Control Theory Gaussian Quadrature Pseudospectral Methods Parallel Computing Techniques Nonlinear programming sequential quadratic programming Heading Angle Proportional Navigation Runge Kutta Methods MATLAB

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