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Attitude Dynamics of Electric Sail from Multibody Perspective

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2018年第12期41卷 2633-2646页

作者： Liu, Fei Hu, Quan Liu, Yufei Beijing Inst Technol Sch Aerosp Engn Beijing 100081 Peoples R China Chinese Acad Space Technol Qian Xuesen Lab Space Technol Beijing 100094 Peoples R China

The electric sail is an innovative propellantless propulsion concept that gains continuous momentum from the solar wind. In this work, the electric sail's attitude dynamics is established from a multibody perspective. Firstly, the dynamics of a single charged tether is described by a dumbbell model. Comparisons with an elastic multipoint model show that the dumbbell model is simpler and accurate enough to describe the motion of tether when the spin rate meets a specific lower bound. Then, the electric sail's attitude dynamics model is established through Kane's method based on the dumbbell model of the tethers. Finally, a case study is performed for the electric sail. It is shown that a 4-kmradius electric sail with 12 tethers of which the voltage is 25 kV could provide the sailcraft with a characteristic acceleration of 0.1 mm/s(2). The results also indicate that the satellite bus's acceleration oscillates with the undiminished out-of-plane swing of the electric sail, in which the period and amplitude are in inverse proportional to the spin rate and its square, respectively. Besides, a dynamical equilibrium point for system's attitude exists when the electric sail is perpendicular to the solar wind. The presented work offers a basic referential model for the real-time feedback control problems of the electric sail's attitude.

关键词： Attitude Stabilization Low Thrust Propulsion Satellite Bus Solar Wind Electron Density Feedback Linearization Electrodynamic Tether Interplanetary Mission Roll Out Solar Array Electric Potential sequential quadratic programming

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A multi-stage optimization technique for simultaneous reconstruction of infrared optical and thermophysical parameters in semitransparent media

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INFRARED PHYSICS & TECHNOLOGY 2018年 92卷 219-233页

作者： Sun, Shuang-Cheng Qi, Hong Wang, Shen-Ling Ren, Ya-Tao Ruan, Li-Ming Harbin Inst Technol Sch Energy Sci & Engn 92 West Dazhi St Harbin 150001 Heilongjiang Peoples R China

A multi-stage optimization technique is proposed to simultaneously reconstruct the infrared optical and thermophysical parameters in semitransparent media. The coupled radiative-conductive heat transfer in two-dimensional absorbing, scattering and emitting medium is solved by the discrete ordinate method combined with finite volume method. The exit radiative intensity and temperature distribution on the boundary are served as input for the inverse analysis, and the sequential quadratic programming is used as the inverse technique. Since the measurement signals are much more sensitive to the infrared absorption and scattering coefficients than to the thermal conductivity of medium, the thermophysical property cannot be accurately reconstructed by the conventional method. The multi-stage optimization technique is developed to solve the inverse estimation tasks, through which the optical and thermophysical parameters are reconstructed in different stages based on different objective functions. All the retrieval results demonstrate that the multi-stage optimization technique is robust and effective in simultaneous estimation of absorption coefficient, scattering coefficient and thermal conductivity. The optical and thermophysical parameters can be reconstructed accurately even with measurement errors.

关键词： Multi-stage optimization technique Image reconstruction Infrared optical parameter Thermal conductivity sequential quadratic programming Inverse technique

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Log Polynomial Velocity Profile for Vertical Landing

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2018年第7期41卷 1617-1623页

作者： Gautam, Alvika Ratnoo, Ashwini Sujit, P. B. Indraprastha Inst Informat Technol Delhi Dept Comp Sci Engn Delhi 110020 India Indian Inst Sci Dept Aerosp Engn Bangalore 560012 Karnataka India Indraprastha Inst Informat Technol Delhi Dept Elect & Commun Engn New Delhi 110020 India Loughborough Univ Aeronaut & Automot Engn Epinal Way Loughborough LE11 3TU Leics England

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Robust Design of Tension Truss Antennas Against Variation in Tension Forces

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AIAA JOURNAL 2018年第8期56卷 3374-3381页

作者： Fu, Kangjia Du, Jianbin Li, Jinyou Zhao, Zhihua Tsinghua Univ Sch Aerosp Engn Beijing 100084 Peoples R China

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Hybrid optimization procedure applied to optimal location finding for piezoelectric actuators and sensors for active vibration control

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APPLIED MATHEMATICAL MODELLING 2018年 62卷 701-716页

作者： Yassin, Belkourchia Lahcen, Azrar Zeriab, Es-Sadek Mohamed Mohammed V Univ ENSET Dept Appl Math & Informat Res Ctr STISM2CS Rabat Morocco KAU Fac Engn Dept Mech Engn Jeddah Saudi Arabia

This paper presents an efficient hybrid optimization approach using a new coupling technique for solving the constrained optimization problems. This methodology is based on genetic algorithm, sequential quadratic programming and particle swarm optimization combined with a projected gradient techniques in order to correct the solutions out of domain and send them to the domain's border. The established procedures have been successfully tested with some well known mathematical and engineering optimization problems, also the obtained results are compared with the existing approaches. It is clearly demonstrated that the solutions obtained by the proposed approach are superior to those of existing best solutions reported in the literature. The main application of this procedure is the location optimization of piezoelectric sensors and actuators for active control, the vibration of plates with some piezoelectric patches is considered. Optimization criteria ensuring good observability and controllability based on some main eigenmodes and residual ones are considered. Various rectangular piezoelectric actuators and sensors are used and two optimization variables are considered for each piezoelectric device: the location of its center and shape orientation. The applicability and effectiveness of the present methodological approach are demonstrated and the location optimization of multiple sensors and actuators are successfully obtained with some main modes and residual ones. The shape orientation optimization of sensors observing various modes as well as the local optimization of multiple sensors and actuators are numerically investigated. The effect of residual modes and the spillover reduction can be easily analyzed for a large number of modes and multiple actuators and sensors. (C) 2018 Elsevier Inc. All rights reserved.

关键词： Coupled optimization Border correction procedure Genetic algorithm sequential quadratic programming Particle swarm optimization Multi-piezoelectric actuators and sensors Optimal placement and orientation

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A two-step approach to damage localization at supporting structures of offshore wind turbines

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STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL 2018年第5期17卷 1313-1330页

作者： Schroeder, Karsten Gebhardt, Cristian Guillermo Rolfes, Raimund Leibniz Univ Hannover Inst Struct Anal Appelstr 9A D-30167 Hannover Germany

This article introduces a new adaptive two-step optimization algorithm for finite element model updating with special emphasis on damage localization at supporting structures of offshore wind turbines. The algorithm comprises an enhanced version of the global optimization algorithm simulated annealing, the simulated quenching method that approximates an initial guess of damage localization. Subsequently, sequential quadratic programming is used to compute the final solution adaptively. For the correlation of numerical model and measurement data, both a measure based on eigenfrequencies and mode shapes and a measure employing time series are implemented and compared with respect to their performance for damage localization. Phase balance of the time signals is achieved using cross-correlation. The localization problem is stated as a minimization problem in which the measures are used in time and modal domain as the objective function subject to constraints. Furthermore, the objective function value of the adjusted model is used to distinguish correct from wrong solutions. The functionality is proven using a numerical model of a monopile structure with simulated damage and a lab-scaled model of a tripile structure with real damage.

关键词： Model updating damage localization simulated quenching sequential quadratic programming

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Gradient-Free Trust-Region-Based Adaptive Response Surface Method for Expensive Aircraft Optimization

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AIAA JOURNAL 2018年第2期56卷 862-873页

作者： Long, Teng Li, Xin Shi, Renhe Liu, Jian Guo, Xiaosong Liu, Li Key Lab Dynam & Control Flight Vehicle Beijing 100081 Peoples R China Beijing Inst Technol Sch Aerosp Engn Beijing 100081 Peoples R China Minist Educ Sch Aerosp Engn Singapore Singapore

This paper presents a novel gradient-free trust region assisted adaptive response surface method for aircraft optimization problems with expensive functions. A gradient-free trust region sampling space approach is developed for design space reduction and sequential sampling, and response surface metamodel refitting enables the trust region assisted adaptive response surface method to possess higher optimization efficiency and better global convergence capability. Besides, an election sequential Latin hypercube sampling method is developed to improve the space-filling property and feasibility of the sequential samples. Moreover, the augmented Lagrangian method is employed to handle expensive constraints. The trust region assisted adaptive response surface method outperforms several adaptive response surface metamodel variants in the comparative study on a number of benchmark problems. Additionally, compared with several other well-known metamodel-based global optimization algorithms, the proposed algorithm also shows favorable performance in global convergence, efficiency, and robustness. Next, the trust region assisted adaptive response surface method is successfully applied to solve an airfoil aerodynamic optimization problem based on computational fluid dynamics simulation to demonstrate its effectiveness for real-world engineering problems. Finally, limitations of the proposed method and future work are discussed.

关键词： Aircrafts Augmented Lagrangian Method NACA 0012 Computational Fluid Dynamics Simulation sequential quadratic programming ICE Lift Coefficient Aircraft Design Process MATLAB Aerodynamic Characteristics

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Simulation and optimization of a continuous biodiesel plant using nonlinear programming

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ENERGY 2019年 189卷

作者： Alvardes, Adan de Oliveira Prata, Diego Martinez Santos, Lizandro de Sousa Univ Fed Fluminense Dept Engn Quim & Petr Rua Passo da Patria 156 BR-24210240 Niteroi RJ Brazil

The continuous production of biodiesel is achieved through a sequence of stages such as reaction, absorption, decantation, and product distillation. These steps require certain performance criteria that must be optimized. Several works have addressed the optimization of the design of biodiesel plants, and these have usually examined modifications to the dimensions and types of equipment or energy integration. However, there is only limited literature available on determining optimal operating conditions for existing processes. In this paper, the steady-state optimization of a soybean continuous biodiesel plant is proposed. To this end, a mathematical model to describe the chemical kinetics of soybean oil trans-esterification was developed and incorporated into a chemical process simulator. The optimization procedure is based on multidimensional sequential quadratic programming (SQP), in which the primary objectives were to minimize the plant's energy consumption subject to a minimum of 99 wt% biodiesel purity. The results reveal that the optimization of the current process allows a 4.45% reduction in energy consumption compared to the base case. Besides, the study also evidenced that the optimization approach can be applied to recalculate the optimal point when possible disturbances can deviate the system from a steady state. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： sequential quadratic programming Nonlinear programming Transesterification

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Some mathematical aspects of price optimisation

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SCANDINAVIAN ACTUARIAL JOURNAL 2018年第5期000卷 379-403页

作者： Hashorva, Enkelejd Ratovomirija, Gildas Tamraz, Maissa Bai, Yizhou Univ Lausanne Dept Actuarial Sci Lausanne Switzerland Vaudoise Assurances Lausanne Switzerland Nankai Univ Sch Math Sci Tianjin Peoples R China

Calculation of an optimal tariff is a principal challenge for pricing actuaries. In this contribution we are concerned with the renewal insurance business discussing various mathematical aspects of calculation of an optimal renewal tariff. Our motivation comes from two important actuarial tasks, namely (a) construction of an optimal renewal tariff subject to business and technical constraints, and (b) determination of an optimal allocation of certain premium loadings. We consider both continuous and discrete optimisation and then present several algorithmic suboptimal solutions. Additionally, we explore some simulation techniques. Several illustrative examples show both the complexity and the importance of the optimisation approach.

关键词： Market tariff optimal tariff price optimisation renewal business sequential quadratic programming

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Local optimum in multi-material topology optimization and solution by reciprocal variables

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STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION 2018年第3期57卷 1283-1295页

作者： Long, Kai Wang, Xuan Gu, Xianguang North China Elect Power Univ Beijing Key Lab Energy Safety & Clean Utilizat Beijing 102206 Peoples R China North China Elect Power Univ State Key Lab Alternate Elect Power Syst Renewabl Beijing 102206 Peoples R China Dalian Univ Technol Dept Engn Mech State Key Lab Struct Anal Ind Equipment Dalian 116024 Peoples R China Hefei Univ Technol Sch Automobile & Traff Engn Hefei 230009 Anhui Peoples R China

It is revealed that the local optimum is particularly prone to occur in multi-material topology optimization using the conventional SIMP method. To overcome these undesirable phenomena, reciprocal variables are introduced into the formulation of topology optimization for minimization of total weight with the prescribed constraint of various structural responses. The SIMP scheme of multi-phase materials is adopted as the interpolation of the elemental stiffness matrix, mass matrix and weight. The sensitivities of eigenvalue and weight with respect to design variables are derived. Explicit approximations of natural eigenvalue and weight are given with the help of the first and second order Taylor series expansion. Thus, the optimization problem is solved using a sequential quadratic programming approach, by setting up a sub-problem in the form of a quadratic program. The filtering technique by solving the Helmholtz-type partial differential equation is performed to eliminate the checkerboard patterns and mesh dependence. Numerical analysis indicates that it is beneficial to avoid the local optimum by using the reciprocal SIMP formulation. Besides, the structure composed of multi-materials can achieve a lighter design than that made from the exclusive base material. The effectiveness and capability of the proposed method are also verified by nodal displacement constraint and multiple constraints.

关键词： Topology optimization Local optimum Multi-phase materials Natural frequency sequential quadratic programming

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