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Collision Avoidance for an Unmanned Aerial Vehicle in the Presence of Static and Moving Obstacles

JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2020年第1期43卷 96-110页

作者： Marchidan, Andrei Bakolas, Efstathios Univ Texas Austin Dept Aerosp Engn & Engn Mech Austin TX 78712 USA

A new collision-avoidance procedure for an unmanned aerial vehicle (UAV) in the presence of static and moving obstacles is presented. The proposed procedure is based on a new form of local parameterized guidance vector fields, called collision-avoidance vector fields, which produce smooth and intuitive maneuvers around obstacles. These vector fields are generated from a decomposition of UAV kinematics and a proximity-based velocity modulation. The proposed kinematic decomposition encodes both collision avoidance and constant-speed motion for the UAV. As such, the resulting maneuvers follow nominal collision-free paths, which are referred to as streamlines of the collision-avoidance vector fields, with constant speed. Next, in accordance with the computed guidance vector fields, different collision-avoidance controllers that generate collision-free maneuvers are developed. Furthermore, it is shown that any tracking controller with convergence guarantees can be used with the avoidance controllers to track the streamlines of the collision-avoidance vector fields. Finally, numerical simulations demonstrate the efficacy of the proposed approach and its ability to avoid collisions with static and moving pop-up threats in different practical scenarios.

关键词： UAV Streamlines Numerical Simulation Motion Planning nonlinear programming Artificial Potential Fields Flight Control System Navigation Function Obstacle Avoidance Radial Velocity

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Multi-objective optimization of a biodiesel production process using process simulation

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JOURNAL OF CLEANER PRODUCTION 2020年 270卷

作者： Goncalves, Paula Ciribeli Costa Monteiro, Luciane Pimentel Santos, Lizandro de Sousa Univ Fed Fluminense Dept Chem Engn & Petr Rua Passo Patria 156 BR-24210240 Niteroi RJ Brazil

Economic and environmental aspects have been contributing to the gradual reduction of fossil fuels and to the growth of research on renewable energy, such as biodiesel, that has been gaining representation in the national and world market. In this scenario, the optimal operation of continuous biodiesel processes may be an attractive tool to optimize some economic/environmental indicators, e.g., biodiesel production and purity, residues, and energy consumption. To develop a multicriteria optimization, a multi-objective methodology must be performed in which two or more functions are used as performance measurements. In this sense, the present work aims to propose the multi-objective optimization (MOO) of a continuous biodiesel plant. The purpose of the optimization was to maximize the biodiesel flow rate and minimize the energy rate consumption subject to a minimum biodiesel purity. An additional study was performed to quantify a set of potential environmental impacts (PEIs) of the optimized scenarios. The results of MOO showed that there is a set of optimal solutions depending on the weights assigned to each individual objective function. It was verified that the reactor temperature has a significant influence on biodiesel production, but less influence on the energy rate consumption. The suggested methodology could serve as a basis for future work addressing multi-criteria optimization, where the optimal operating point solution depends on the decision-maker. These results suggest that the PEIs can serve as environmental constraints for the optimization problem, allowing the decision maker to evaluate these criteria for choosing the optimum operating point. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： UNISIM nonlinear programming Pareto set

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Solving a production-routing problem with price-dependent demand using an outer approximation method

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COMPUTERS & OPERATIONS RESEARCH 2020年 123卷

作者： Torkaman, Somayeh Jokar, Mohammad Reza Akbari Mutlu, Nevin Van Woensel, Tom Sharif Univ Technol Ind Engn Dept Tehran Iran Eindhoven Univ Technol Sch Ind Engn Eindhoven Netherlands

A production-routing problem with price-dependent demand (PRP-PD) is studied in this paper. Demand follows a general convex, differentiable, continuous and strictly decreasing function in price. The problem is modeled as a mixed integer nonlinear program (MINLP). Two Outer Approximation (OA) based algorithms are developed to solve the PRP-PD. The efficiency of the proposed algorithms in comparison with commercial MINLP solvers is demonstrated. The computational results show that our basic OA algorithm outperforms the commercial solvers both in solution quality and in computational time aspects. On the other hand, our extended (two-phase) OA algorithm provides near-optimal solutions very efficiently, especially for large problem instances. These findings prevail both for linear and for nonlinear demand functions. Additional sensitivity analyses are conducted to investigate the impact of different problem parameters on the optimal solution. The results show that the manufacturer should give higher priority to the retailer who has lower price sensitivity and who is closer to the manufacturer. Another takeaway is that a larger market size and a lower price sensitivity lead to more profit. (C) 2020 Published by Elsevier Ltd.

关键词： nonlinear programming Production-routing Pricing Outer approximation

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The Comparison of Lately Proposed Harris Hawks Optimization and Jaya Optimization in Solving Directional Overcurrent Relays Coordination Problem

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COMPLEXITY 2020年第1期2020卷

作者： Yu, Jiangtao Kim, Changhwan Rhee, Sang-Bong Anyang Inst Technol Dept Elect Informat & Elect Engn Anyang 455000 Peoples R China Yeungnam Univ Dept Elect Engn Kyonsan 38541 South Korea

In this paper, a lately proposed Harris Hawks Optimizer (HHO) is used to solve the directional overcurrent relays (DOCRs) coordination problem. To the best of the authors' knowledge, this is the first time HHO is being used in the DOCRs coordination problem. The main inspiration of HHO is the cooperative behavior and chasing style of Harris' hawks from different directions, based on the dynamic nature of scenarios and escaping patterns of the prey. To test its performances in solving the DOCRs coordination problem, it is adopted in 3-bus, 4-bus, 8-bus, and 9-bus systems, which are formulated by three kinds of optimization models as linear programming (LP), nonlinear programming (NLP), and mixed integer nonlinear programming (MINLP), according to the nature of the design variables. Meanwhile, another lately proposed optimization algorithm named Jaya is also adopted to solve the same problem, and the results are compared with HHO in aspects of objective function value, convergence rate, robustness, and computation efficiency. The comparisons show that the robustness and consistency of HHO is relatively better than Jaya, while Jaya provides faster convergence rate with less CPU time and occasionally more competitive objective function value than HHO.

关键词： nonlinear programming

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MOS Amplifier Design Methodology for Optimum Performance

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IETE JOURNAL OF RESEARCH 2020年第4期66卷 478-490页

作者： Mondal, Abir J. Bhattacharjee, Paromita Chakraborty, Pinaki Bhattacharyya, Bidyut K. Natl Inst Technol Dept Elect & Commun Engn Yupia 791112 Arunachal Prade India Indian Inst Technol Guwahati Gauhati 781039 Assam India Natl Inst Technol Dept Basic & Appl Sci Yupia 791112 Arunachal Prade India Natl Inst Technol Dept Elect & Commun Engn Agartala 799046 India

While trying to represent the performance metrics of a single-stage amplifier as a function of designable parameters, it is observed that the corresponding metrics form a polytope-type feasible region. Indeed, the polytope so formed is made up of performance metrics which can either be objectives or constraints. Initially, the simplex method is used to obtain an objective value that satisfies a set of constraints. Once the objective is available, the interior point-based method is used to check whether any objective lies inside the feasible region or not. The proposed design flow examines both the periphery and the interior of the polytope so generated. Henceforth, the design of an amplifier can be pointed out to be a distinctive type of optimization concern, called nonlinear programming (NLP). Furthermore, efficient global optimization methods have been established to yield an automated synthesis of amplifiers derived from the requirements. In this work, the formulation of the design problem for a cascode amplifier as NLP is described and analyzed. Thereafter, the optimal trade-off curves related to the performance metrics such as small signal gain (Av), unity gain frequency (UGF) or gain bandwidth product (GBWP), and power are derived in order to observe the corresponding dependencies.

关键词： Amplifier circuits nonlinear programming Simplex method Small signal gain Slew rate Unity gain frequency

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Inference for confidence sets of the generalized inverted exponential distribution under k-record values

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JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS 2020年 380卷

作者： Wang, Liang Tripathi, Yogesh Mani Wu, Shuo-Jye Zhang, Meng Yunnan Normal Univ Sch Math Kunming Yunnan Peoples R China Indian Inst Technol Patna Dept Math Patna Bihta India Tamkang Univ Dept Stat Taipei Taiwan Changan Univ Sch Sci Xian Peoples R China

Based on the k-record values, confidence sets are explored for the parameters of the generalized inverted exponential distribution. Series of exact balanced confidence intervals and exact confidence regions are constructed using pivotal quantities. In order to obtain minimum-size confidence sets, constrained optimization problems are also discussed, and the associated nonlinear programming procedures are established by minimizing Lagrangian functions. Shortest-length confidence intervals and smallest-area confidence regions for the unknown parameters can be obtained by simultaneously solving nonlinear system. Finally, two real data examples and a simulation study are provided for illustrative purposes. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Generalized inverted exponential distribution k-records Pivotal quantities Optimal confidence sets nonlinear programming

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Minimum Bounds on Multispacecraft ΔV Optimal Cooperative Rendezvous

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2020年第12期43卷 2333-2348页

作者： Venigalla, Chandrakanth Scheeres, Daniel J. Univ Colorado Aerosp Engn Sci Boulder CO 80309 USA

Time- and orientation-free Delta V optimal transfers are used to investigate optimal rendezvous orbits for cooperative systems of two and more spacecraft. The problem of finding total Delta V optimal cooperative rendezvous orbits is formulated and solved as a nonlinear programming problem using analytic expressions for optimal orbit transfer Delta V costs. Each spacecraft has propulsive abilities, and optimal rendezvous orbits are found for planar (match semimajor axis and eccentricity) and three-dimensional (match semimajor axis, eccentricity, and inclination) scenarios. The Delta V costs found for this type of rendezvous are lower-bound costs for finite-time full rendezvous where all spacecraft would have matching sets of all six orbit elements. This lower-bound Delta V cost, which is realizable for full rendezvous given infinite time and secular J2 perturbations, is shown to be also realizable for finite-time full rendezvous if certain initial conditions can be met. Finally, application of the cooperative rendezvous problem to constellation deployment is briefly discussed.

关键词： nonlinear programming Constellations Orbital Inclination Optimal Impulsive Maneuvers Spacecraft Trajectories Spacecraft Rendezvous Spacecraft System Small Satellites Earth Particle Swarm Optimization

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Improved Sequential Convex programming Algorithms for Entry Trajectory Optimization

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JOURNAL OF SPACECRAFT AND ROCKETS 2020年第6期57卷 1373-1386页

作者： Wang, Zhenbo Lu, Ye Univ Tennessee Dept Mech Aerosp & Biomed Engn Knoxville TN 37996 USA Kent State Univ Coll Aeronaut & Engn Kent OH 44242 USA

Entry trajectory optimization for hypersonic vehicles has been formulated as constrained optimal control problems, which are difficult to solve because of the existing high nonlinearity and nonconvexity. In recent years, convex optimization has shown promise for real-time onboard applications with the state-of-the-art interior-point methods. In this paper, line-search and trust-region techniques are introduced to fundamentally improve the performance of the sequential convex programming method for entry trajectory optimization. Two improved algorithms are developed: line-search sequential convex programming and trust-region sequential convex programming. In addition, a new trajectory generation method is proposed by taking advantage of the predictor-corrector method to find an initial 3-D trajectory for the developed successive algorithms. As such, the convergence of the solution process is improved. To demonstrate the effectiveness and performance of the newly proposed algorithms, numerical simulations are presented for maximum-terminal-velocity and minimum-heat-load entry problems. Results show that these two problems are not well solved using the basic sequential convex programming algorithm. However, they can be efficiently solved by the two improved algorithms in a few seconds in MATLAB, showing a significant improvement over general-purpose solvers, such as GPOPS.

关键词： Pseudospectral Optimal Control nonlinear programming Terminal Velocity Predictor Corrector Method Numerical Simulation MATLAB Hypersonic Vehicles Aerodynamic Coefficients Earth Flight Path Angle

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Partial Observability Analysis of an Adversarial Swarm Model

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2020年第2期43卷 250-261页

作者： Gong, Qi Kang, Wei Walton, Claire Kaminer, Isaac Park, Hyeongjun Univ Calif Santa Cruz Dept Appl Math Santa Cruz CA 95064 USA Naval Postgrad Sch Dept Appl Math Monterey CA 93940 USA Naval Postgrad Sch Dept Mech & Aerosp Engn Monterey CA 93940 USA New Mexico State Univ Dept Mech & Aerosp Engn Las Cruces NM 88003 USA

This paper introduces a new concept of partial observability for nonlinear systems. This new approach enables a quantitative analysis on the observability of an individual state variable and unknown parameters of a nonlinear dynamics even when the system is not observable in the traditional sense. The paper develops theoretical properties of partial observability and its computational algorithms. These results are applied and validated on a nonstandard estimation problem of detecting the internal cooperating strategy of a particular adversarial swarm model. Partial observability analysis on the parameters that define the cooperating strategy reveals interesting findings. For example, some parameters are observable even when the swarm is at a steady state that is not observable in traditional sense. It is also shown that observability of the internal cooperating strategy depends on both the swarm trajectory and the time window of the measurement. Motivated by these findings, a variational method of estimation based on the dynamic optimization of a cost function is proposed. Simulation results show that the proposed estimation method outperforms Kalman filters. The results in this paper provide useful tools for applications involving adversarial swarms, including defense against swarm attacks and herding of biological swarms.

关键词： Unscented Kalman Filter Mathematical Models nonlinear Dynamics Classical Control Theory Lagrange Multipliers Singular Value Decomposition Naval Research Laboratory nonlinear programming MATLAB Trajectory Optimization

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Nondestructive Estimation of Magnetization Distribution in Permanent Magnet Using Quasi-Newton Method Based on 2-D Fourier Series Expansion

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IEEE TRANSACTIONS ON MAGNETICS 2020年第1期56卷

作者： Nakamura, Narichika Okamoto, Yoshifumi Osanai, Kenta Doi, Satoshi Aoki, Tetsuya Okazaki, Keichi Hosei Univ Dept Elect & Elect Engn Tokyo 1848584 Japan Denso Corp Mat Engn Res & Dev Div Kariya Aichi 4488661 Japan Denso Corp Adv Motor Res & Dev Div Kariya Aichi 4488661 Japan

A permanent magnet (PM) with an accurate magnetization distribution is required for the design of high-quality electrical machines. The nondestructive diagnosis of the magnetization distribution in PM is essential to facilitate the practical design of the synchronous machines. While some methods for magnetization evaluation have been proposed, an optimal method has not been established due to the indefiniteness of the magnetization distribution. Then, the method using nonlinear programming based on the 1-D Fourier series expansion has been proposed by the authors. In this article, the method based on the 2-D Fourier expansion is proposed. The performance of the proposed method was demonstrated in PM, in which orientations were set to parallel and polar isotropic. The performance of the proposed method is compared with the singular value decomposition method.

关键词： Fourier series expansion magnetization distribution nonlinear programming singular value decomposition (SVD)

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