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High-Order Resolution of Multidimensional Compressible Reactive Flow Using Implicit Shock Tracking

AIAA JOURNAL 2021年第1期59卷 150-164页

作者： Zahr, Matthew J. Powers, Joseph M. Univ Notre Dame Dept Aerosp & Mech Engn 300B Cushing Hall Notre Dame IN 46556 USA Univ Notre Dame Dept Aerosp & Mech Engn 366 Fitzpatrick Hall Notre Dame IN 46556 USA

A recently developed high-order implicit shock tracking method is novelly applied to a benchmark problem in two-dimensional compressible reactive flow, and results of remarkably high accuracy are achieved relative to competing shock capturing schemes. High-order implicit shock tracking is a discontinuous Galerkin discretization of conservation laws that simultaneously computes an approximate flow solution and aligns faces of the computational mesh with discontinuities in the flow to provide nonlinear stabilization and an improved approximation to the solution. The model problem is chosen such that its exact solution is available in analytic form to facilitate a detailed study of the truncation error of the tracking method relative to a nominally fifth-order weighted essentially nonoscillatory method. We show the implicit tracking method is able to robustly align the mesh with the shock and, particularly for polynomial bases of degree greater than 1, provide a high-quality approximation to the exact solution on meshes far coarser than required by standard methods. Finally, we demonstrate the tracking method obtains near optimal convergence rates in several error metrics for the problem under consideration.

关键词： Freestream Conditions Vorticity Euler Equations Detonation Adaptive Mesh Refinement Shock Capturing Method Specific Heat Chemically Reacting Flow Compressible Fluid sequential quadratic programming

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Optimal Control for a Cooperative Rendezvous Between Two Spacecraft from Determined Orbits

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JOURNAL OF THE ASTRONAUTICAL SCIENCES 2016年第1期63卷 23-46页

作者： Feng, Weiming Han, Liping Shi, Lei Zhao, Di Yang, Kun Shandong Univ Dept Engn Mech Jinan 260062 Peoples R China Washington Univ Dept Mech Engn & Mat Sci St Louis MO 63130 USA

The mathematical model of a far-distance cooperative rendezvous between two spacecraft in a non-Keplerian orbit was established. Approximate global optimization was performed by a type of hybrid algorithm consisting of particle swarm optimization and differential evolution. In this process, the double-fitness function was established according to the objective function and the constraints;the double-fitness function was used to enable a better choice between the solutions obtained by the two algorithms at every iteration. In addition, the costate variables obtained were set as the initial values of the sequential quadratic programming to greatly increase the possibility of finding the approximate global optimal solution. After performing the calculations and simulations, it was concluded that the fuel required for orbiting was not influenced by the initial positions of the two spacecraft if the initial orbits of the two spacecraft were determined. However, the time consumption is strongly influenced in this situation.

关键词： Cooperative rendezvous Hybrid algorithm sequential quadratic programming Optimal control

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Surface Mesh Movement Algorithm for Computer-Aided-Design-Based Aerodynamic Shape Optimization

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AIAA JOURNAL 2016年第2期54卷 542-556页

作者： Truong, Anh H. Zingg, David W. Haimes, Robert Univ Toronto Inst Aerosp Studies 4925 Dufferin Street Toronto ON M3H 5T6 Canada Univ Toronto JA Bombardier Fdn Chair Aerosp Flight 4925 Dufferin Street Toronto ON M3H 5T6 Canada Univ Toronto Computat Aerodynam & Environmentally Friendly Air Inst Aerosp Studies 4925 Dufferin Street Toronto ON M3H 5T6 Canada MIT 77 Massachusetts Ave Cambridge MA 02139 USA

This paper focuses on the development of a surface mesh movement algorithm suitable for computer-aided-design-based aerodynamic shape optimization. The algorithm interrogates the computer-aided-design system via the vendor-neutral application programming interface Computational Analysis programming Interface and uses the Computational Analysis programming Interface's watertight triangulation of a modified computer-aided-design geometry to guide the movement of the structured surface mesh as the geometry changes during the optimization process. A mapping procedure is introduced that not only preserves the characteristics of the original surface mesh but also guarantees that the new mesh points are on the computer-aided-design geometry. The deformed surface mesh is then smoothed in the parametric space before it is transformed back into three-dimensional space. The procedure is efficient, in that all the processing is done in the parametric space, incurring minimal computational cost. The mesh movement tool is integrated into a three-dimensional shape-optimization framework, with a linear-elasticity volume-mesh movement algorithm, a Newton-Krylov flow solver for the Euler equations, and a discrete-adjoint gradient-based optimizer. The accuracy of the computed gradients is verified through a number of examples.

关键词： Aerodynamic Shape Optimization Computer Aided Design Application programming Interface Shape Optimization Linear Elasticity Euler Equations Angle of Attack Multidisciplinary Design Optimization sequential quadratic programming Mesh Parameterization

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Optimization of hydraulic power take-off system settings for point absorber wave energy converter

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RENEWABLE ENERGY 2022年第0期194卷 938-954页

作者： Amini, Erfan Mehdipour, Hossein Faraggiana, Emilio Golbaz, Danial Mozaffari, Sevda Bracco, Giovanni Neshat, Mehdi Univ Tehran Coll Engn Sch Civil Engn Tehran Iran Polytech Univ Turin Dept Mech & Aerosp Engn Turin Italy Urmia Univ Dept Water Engn Orumiyeh Iran Torrens Univ Australia Ctr Artificial Intelligence Res & Optimizat Brisbane Australia

Ocean wave renewable energy is becoming a key part of the renewable energy industry over the recent decades. By developing wave energy converters (WECs), their power take-off (PTO) systems have been investigated to enhance the power extraction from the ocean. Adjusting PTO parameters is a challenging optimization problem because there is a complex and nonlinear relationship between these parameters and the absorbed power output. In this regard, this study aims to optimize the PTO system parameters of a point absorber wave energy converter in the wave data-set in Perth, on the Western Australian coasts. The converter is numerically designed to oscillate against irregular and multi-dimensional waves and sensitivity analysis for PTO settings. Then, to find the optimal PTO system parameters which lead to the highest power output, ten optimization approaches are incorporated to solve the nonlinear problem, including the Nelder-Mead search method, Active-set method, sequential quadratic programming method (SQP), Multi-Verse Optimizer (MVO), and six modified combination of Genetic, Surrogate and fminsearch techniques. After a feasibility landscape analysis, the optimization outcome is carried out and gives us the best answer in terms of PTO system settings. Finally, the investigation shows that the modified combinations of Genetic, Surrogate, and fminsearch approaches can outperform the others in the selected wave scenario, as well as with regard to the interaction between PTO system variables. (c) 2022 Elsevier Ltd. All rights reserved.

关键词： Wave energy conversion Power take-off Optimization Nelder-Mead Multi-verse optimizer sequential quadratic programming

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Hybrid GSA-SQP algorithm for optimal coordination of directional overcurrent relays

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IET GENERATION TRANSMISSION & DISTRIBUTION 2016年第8期10卷 1928-1937页

作者： Radosavljevic, Jordan Jevtic, Miroljub Univ Pristina Kosovska Mitrovica Elect Engn Fac Tech Sci Kneza Milosa 7 Kosovska Mitrovica 38220 Serbia

This study presents a hybrid gravitational search algorithm-sequential quadratic programming (GSA-SQP) algorithm based on the GSAand SQP to optimal coordination of directional overcurrent relays (DOCRs). The SQP routine is incorporated in GSA as a local search mechanism to improve the performance of the conventional GSA algorithm. The coordination between DOCRs is formulated as a non-linear and highly constrained optimisation problem in which two settings namely time dial setting and pick up current setting of each relay are considered as decision variables. The main objective is to minimise the sum of operating times of all the primary relays, which are expected to operate in order to clear the faults of their corresponding zones. Performance of this approach is studied and evaluated on three different test systems with 6, 24 and 38 relays. Simulation results show that the proposed approach provides effective and robust high-quality solution of the problem.

关键词： search problems overcurrent protection relay protection quadratic programming nonlinear programming hybrid GSA-SOP algorithm directional overcurrent relay protection gravitational search algorithm sequential quadratic programming DOCR constrained optimisation problem nonlinear optimisation problem time dial setting pick up current setting

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A modified SQP-filter method and its global convergence

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APPLIED MATHEMATICS AND COMPUTATION 2007年第1期194卷 92-101页

作者： Su, Ke Che, Jianren Tongji Univ Dept Surveying & Geoinformat Shanghai 200092 Peoples R China Tongji Univ Dept Math Shanghai 200092 Peoples R China

For current sequential programming (SQP) type algorithms, there exist two problems. One is that there are many quadratic programming subproblems are needed to be solved per iteration, the other is that the search direction may be unbounded and caused the sequence to be divergent. In this paper, we presented a modified SQP-filter method based on the modified quadratic subproblem proposed in Zhou [G. L. Zhou, A modified SQP method and its global convergence, J. Global Optim. 11 (1997) 193-205]. This method has no demand on the initial point, and need not using a penalty parameter, which could be problematic to obtain. What is more, the subproblem is feasible at each iterate point. Under some conditions, the global convergence property is obtained. (c) 2007 Elsevier Inc. All rights reserved.

关键词： constrained optimization KKT point sequential quadratic programming global convergence

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Robust Optimization for Dynamic Economic Dispatch Under Wind Power Uncertainty With Different Levels of Uncertainty Budget

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IEEE ACCESS 2016年 4卷 7633-7644页

作者： Zhang, Huifeng Yue, Dong Xie, Xiangpeng Nanjing Univ Posts & Telecommun Inst Adv Technol Nanjing Jiangsu Peoples R China

Since dynamic economic dispatch with wind power uncertainty poses great challenges for power system operation due to its non-linear and uncertain characteristics, this paper proposes a robust optimization model with different levels of uncertainty budget. The dynamic economic dispatch problem is converted into the robust optimization model with an uncertainty budget, which transforms the nondeterministic model into a deterministic optimization problem. Differential evolution is improved by the sequential quadratic programming method and utilized to solve the robust optimization model. Due to the complex-coupled constraints among thermal units, several constraint-handling procedures are proposed to address those constraint limits, which have a significant impact on the efficiency of the whole optimization. The robust optimization model with an adjustable uncertainty budget is implemented in two test systems. The results obtained for the first test system prove the efficiency of differential evolution-based sequential quadratic programming and the constraint-handling procedures;the performance of the second test system reveals that the robust optimization method with different levels of uncertainty budget provides a promising method for solving the dynamic economic dispatch problem with wind power uncertainty.

关键词： Dynamic economic dispatch wind power robust optimization differential evolution sequential quadratic programming uncertainty budget

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A NEIGHBORING EXTREMAL SOLUTION FOR OPTIMAL SWITCHED IMPULSIVE CONTROL PROBLEMS WITH LARGE PERTURBATIONS

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INTERNATIONAL JOURNAL OF INNOVATIVE COMPUTING INFORMATION AND CONTROL 2012年第9期8卷 6235-6257页

作者： Jiang, Canghua Teo, Kok Lay Loxton, Ryan Duan, Guang-Ren Harbin Inst Technol Ctr Control Theory & Guidance Technol Harbin 150001 Peoples R China Curtin Univ Technol Dept Math & Stat Perth WA 6845 Australia

This paper presents an approach to compute the neighboring extremal solution for an optimal switched impulsive control problem with a pre-specified sequence of modes and a large perturbation in the initial state. The decision variables - the subsystem switching times and the control parameters - are subject to inequality constraints. Since the active status of these inequality constraints may change under the large perturbation, we add fractions of the initial perturbation separately such that the active status of the inequality constraints is invariant during each step, and compute the neighboring extremal solution iteratively by solving a sequence of quadratic programming problems. First, we compute a correction direction for the control in the perturbed system through an extended backward sweep technique. Then, we compute the maximal step size in this direction and derive the solution iteratively by using a revised active set strategy. An example problem involving a shrimp harvesting operation demonstrates that our solution approach is faster than the sequential quadratic programming approach.

关键词： Optimal control Neighboring extremal Impulsive control Switched system sequential quadratic programming Active set strategy

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Reinforcement Learning-Based Optimal Flat Spin Recovery for Unmanned Aerial Vehicle

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2017年第4期40卷 1074-1081页

作者： Kim, Donghae Oh, Gyeongtaek Seo, Yongjun Kim, Youdan Seoul Natl Univ Dept Mech & Aerosp Engn Seoul 08826 South Korea Seoul Natl Univ Dept Mech & Aerosp Engn Inst Adv Aerosp Technol Seoul 08826 South Korea

A study proposed an reinforcement learning (RL)-based optimal controller to recover the aircraft from flat spin mode to steady level flight in minimum time. Stable upset modes including flat spin were investigated via a bifurcation diagram (BD). A two-phase controller including an RL block was designed, angular velocity was attenuated to a safe margin, and in the second phase, the attitude controller restored the aircraft to level flight. The performance of the proposed controller was demonstrated by comparing the numerical simulation result to that of the optimal trajectory obtained by a sequential quadratic programming (SQP) and a genetic algorithm (GA).

关键词： UAV Reinforcement Learning Elevator Deflection Ailerons Sideslip Angle Trajectory Optimization Level Flight sequential quadratic programming Nonlinear programming Linear quadratic Regulator

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Electric-propulsion spacecraft optimization for lunar missions

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JOURNAL OF SPACECRAFT AND ROCKETS 1996年第2期33卷 235-239页

作者： Kluever, CA Chang, KR University of Missouri—Columbia/Kansas City Kansas City Missouri 64110-2499

A quick and efficient method for computing the optimal vehicle-trajectory combination for lunar missions using electric propulsion is developed, The problem involves computing the optimal spacecraft sizing parameters and trajectory shaping parameters that maximize the payload for a one-way, fixed-trip-time, planar transfer from circular Earth orbit to circular low lunar orbit, The computational load of the problem is reduced by utilizing universal low-thrust trajectory solutions to approximate the Earth-escape and moon-capture spiral trajectories, Several maximum-payload solutions are obtained for both nuclear electric-propulsion and solar electric-propulsion spacecraft, The nuclear results show a very good match with published exact trajectories, A sensitivity analysis of the assumed electric-propulsion technology level is also performed.

关键词： Nuclear Electric Propulsion Cargo Spacecraft Spacecraft Mission Earth Magnetoplasmadynamic Thruster Propellant Trajectory Optimization sequential quadratic programming Vehicle Trajectories Numerical Integration

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