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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Xu, Hao Sheng, Yu Harbin Inst Technol Engine Aerodynam Res Ctr Harbin 150001 Peoples R China Univ Virginia Dept Elect & Comp Engn Charlottesville VA 22903 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

In this paper, we propose a propulsion blade design for multirotor systems under actuator failures. The key challenge of the research is to balance the propulsion efficiency and performance on both rotating directions. The fault tolerant performance of multirotor aircrafts is restricted by the unidirectional rotors that are not allowed to rotate reversely, while the bidirectional rotors can aid a multirotor to accommodate more patterns of actuator failures and enhance the resilience in severe environment. The shape of propeller blades is designed to meet desired aerodynamic performance. A hybrid optimization design process is carried out to produce rotor blades for specific requirements. An integrated method is used to reduce the computational costs and achieve global optimal, which is a combination of genetic algorithm and non-linear programming.

关键词： Propeller blades propulsive efficiency Fault tolerance global optimum ROTOR BLADE nonlinear programming Bidirectional Resilience Rotors Genetic Algorithm (GA)

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Consensus-based Moment Allocator for Distributed nonlinear Actuators onboard a Conceptual SUAS

Consensus-based Moment Allocator for Distributed Nonlinear A...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Mark, August Xu, Yunjun Dickinson, Benjamin T. Univ Cent Florida Dept Mech & Aerosp Engn Orlando FL 32816 USA Air Force Res Lab Munit Directorate Eglin AFB FL 32542 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

In this study, a distributed scheme is developed for actuators aboard of a small unmanned aerial system to achieve consensus in allocating aerodynamic moment contributions among them. These actuators include the main control surfaces (aileron, rudder, and elevator) governed by 2nd order linear ordinary differential equations and distributed micro-scale synthetic jets governed by 2nd order nonlinear ordinary differential equations. This research is to address one technical gap about how to actuate control surfaces and synthetic jets in responding to the rich amount of information measured using micro-scale flow sensors (e.g. pressure and shear stress). The proposed allocator has three components to cancel nonlinear terms, achieve consensus, and track the desired total aerodynamic moment. In addition, weighting matrix is added to solve the issue relating to control limitations in synthetic jets and control surface deflections. Different from traditional centralized optimization based allocation approaches, the newly developed allocation scheme is decentralized, in a feedback form, and able to respond to uncertainties and noise. A Lyapunov approach is used to prove the asymptotically stability of the closed-loop system, and simulations are used to validate the proposed control allocator.

关键词： nonlinear Actuators Control Surfaces Aerodynamic Moments State Space Representation Unmanned Aerial Systems Shear Stress Flow Sensors nonlinear programming Flow Separation Dielectric Barrier Discharge

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Application of Chance-Constrained Optimal Control to Optimal Obstacle Avoidance

Application of Chance-Constrained Optimal Control to Optimal...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Keil, Rachel E. Aggarwal, Rachit Kumar, Mrinal Rao, Anil, V Univ Florida Dept Mech & Aerosp Engn Gainesville FL 32611 USA Ohio State Univ Dept Mech & Aerosp Engn Columbus OH 43210 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

The problem of optimal obstacle avoidance in the presence of chance constraints is considered using the time minimization of a Dubin's car with a circular keep-out zone. Three cases of the Dubin's car problem are explored. For the first case, the only constraint is the circular keep out zone. For the second case, a three-sided box with side length equal to the diameter of the keep out zone is added as a second path constraint and for which the deterministic optimal control problem is unsolvable. The keep out zone is then transformed to have a probabilistic boundary, converting the problem from a deterministic to a chance-constrained optimal control problem. A Split-Bernstein approximation method is used to transform the chance constraint into a deterministic nonlinear constraint. The chance-constrained optimal control problem is solvable and the solution has a lower optimal cost than that of the first deterministic optimal control problem. Thus in certain applications there is a correlation between a lower optimal cost and higher risk that has numerous practical applications. Numerical results are shown that demonstrate the effectiveness of the technique.

关键词： Optimal Control Obstacle Avoidance Lagrange Multipliers nonlinear programming Hamiltonian Monte Carlo Probability Density Functions Autonomous Robot Path Planning Air Vehicle

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Implementation of Physical Subspace Identification on a Realistic Helicopter

Implementation of Physical Subspace Identification on a Real...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Avcioglu, Sevil Kutay, A. Turker Leblebicioglu, Kemal Turkish Aerosp Ind Helicopter Div Flight Mech & Autopilot Syst TR-06980 Ankara Turkey Middle East Tech Univ Aerosp Engn TR-06800 Ankara Turkey Middle East Tech Univ Elect & Elect Engn TR-06800 Ankara Turkey

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

In this study, the processes of subspace identification and parameter estimation are applied to a realistic multi role helicopter. This sequential procedure, which is recently cited as "physical subspace identification", begins with data gathering. The required subspace identification data is obtained by using FLIGHTLAB linearized model. The 3-2-1-1 type excitation signals are applied in series via lateral cyclic, longitudinal cyclic, pedal, and collective channels and the translational velocity components (longitudinal, lateral and vertical), angular velocity components (roll, pitch and yaw), and Euler angles (roll and pitch) are collected in a single test case. The conventional subspace identification algorithms are performed to estimate state space model of a system for a certain test condition. The state space matrices, which are not necessarily associated with the physical states, are transformed into the equivalently physical forms via optimization. The objective function, which is generated by summing the square of similarity transformation equations, is minimized to find the physical system parameters. Considering both the size of the unknowns, which is more than hundreds in this problem and the form of the objective function that consists of nonlinear equations to be solved, the "large-scale" nonlinear optimization algorithms are used to estimate the physical parameters. The constraints and the initial conditions are defined in line with a physical insight. The performance of the methodology is discussed in the final section and some improving proposals are submitted to enhance the study for future applications.

关键词： Helicopters Mathematical Models Optimization Algorithm Euler Angles Yaw Flight Testing Singular Value Decomposition nonlinear programming Stability Derivatives Wind Tunnel Tests

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Trajectory Optimization for Long-Range Air-Defense Missile with a Constraint on Capability of Error Correction 38

Trajectory Optimization for Long-Range Air-Defense Missile w...

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38th Chinese Control Conference (CCC)

作者： Lv, Shoukun Cai, Mingchun Zhou, Zhou Di Wang, Zicai Beijing Inst Elect Syst Engn Beijing 100854 Peoples R China Harbin Inst Technol Dept Control Sci & Engn Harbin 150001 Peoples R China Harbin Inst Technol Ctr Control & Simulat Harbin 150001 Peoples R China

ISBN: (纸本)9789881563972

A method of designing optimal parabolic trajectory for long range air-defense interceptor missile with a constraint on capability of error correction in its terminal guidance phase is proposed. In this method a constraint condition on the error correction capability in finite terminal guidance phase for the missile with bounded acceleration is presented to replace the traditional constraint on instantaneous normal acceleration. A minimum time problem under the constraint is solved using the nonlinear programming optimal control theory. Simulation results for some typical scenarios of long range interception show that the optimal trajectories satisfy a series of constraints including not only the error correction capability, but also the constraint on and maximum angle of attack, and the constraints on terminal flight path angle and terminal velocity.

关键词： Interceptor Trajectory optimization Constraint nonlinear programming

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Aggregated GP-based Optimization for Contaminant Source Localization

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OPERATIONS RESEARCH PERSPECTIVES 2020年 7卷

作者： Krityakierne, Tipaluck Baowan, Duangkamon Mahidol Univ Fac Sci Dept Math Bangkok 10400 Thailand CHE Ctr Excellence Math Bangkok 10400 Thailand

Recently a new simulation-based optimization benchmark of groundwater contaminant source localization problems has been introduced to the hydrogeological science community. Given information on contaminant concentration levels at each monitoring well and each time step, its objective is to identify the location of contaminant source. In this work, we analyze and look at the problem from different angles to gain more insights on this class of groundwater problems. To tackle the problem, a novel simulation-based optimization algorithm relying on an aggregated Gaussian process model, and the expected improvement criterion is introduced. Results from this study show that the proposed algorithm, though relying on an approximated Gaussian process model, demonstrates superior efficiency and reliability than a traditional expected improvement-based algorithm. The location of the monitoring wells was confirmed to play a crucial role in assisting the optimization algorithm to accurately localize the contaminant source. Additional monitoring wells, while adding more knowledge of the space-time mapping of concentration levels, could nevertheless slow down convergence of the algorithm due to the increase in problem complexity.

关键词： Contaminant source localization Groundwater management Expected improvement nonlinear programming Simulation-based optimization

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Fuel-Optimal Rocket Landing with Aerodynamic Controls

Fuel-Optimal Rocket Landing with Aerodynamic Controls

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AIAA Guidance, Navigation, and Control Conference and Exhibit

作者： Liu, Xinfu Beijing Inst Technol Sch Aerosp Engn Beijing 100081 Peoples R China

ISBN: (数字)9781624104503

ISBN: (纸本)9781624104503

Aerodynamic forces are not negligible for a reusable rocket returning back to Earth. How the aerodynamic controls and propulsion should be coordinated to realize fuel-optimal precise landing is addressed in this paper. To this end, a model-based optimal control problem is formulated with the rocket's angle of attack and thrust as control inputs, and constraints on the controls are included to reflect the capabilities of the vehicle. Precise landing requires the (highly nonlinear and nonconvex) problem to be solved onboard in real time. This ability of online computation is becoming increasingly desired in aerospace guidance and control for autonomous missions. Hence, this paper presents how to solve the rocket landing problem via convex optimization that has guaranteed polynomial-time complexity. Specifically, a novel methodology of handling the rocket nonlinear dynamics is introduced, and a relaxation technique used to convexify nonconvex constraints is theoretically proved to be valid. High efficiency of the proposed method, with potential for online computation, is demonstrated by numerical examples and comparisons with other methods.

关键词： Rocket Trajectories Fuels Lift Coefficient Aerodynamic Force Trajectory Optimization Earth nonlinear programming Flight Path Angle Fuel Consumption Lift to Drag Ratio

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A risk-gain dominance maximization approach to enhanced index tracking

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FINANCE RESEARCH LETTERS 2019年 29卷 231-238页

作者： Cesarone, Francesco Lampariello, Lorenzo Sagratella, Simone Roma Tre Univ Dept Business Studies Rome Italy Sapienza Univ Rome Dept Comp Control & Management Engn Antonio Rober Rome Italy

Following the research strands of enhanced index tracking and of portfolio performance measures optimization, we propose to choose, among the feasible asset portfolios of a given market, the one that maximizes the geometric mean of the differences between its risk and gain and those of a suitable reference benchmark, such as the market index. This approach, which has a peculiar geometric interpretation and enjoys remarkable features, provides the efficient portfolio that dominates the largest amount of portfolios dominating the reference benchmark index. Preliminary empirical results highlight good out-of-sample performances of our approach compared with those of the market index.

关键词： Asset allocation Portfolio performance measures optimization Enhanced indexation nonlinear programming

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A second-order convergence augmented Lagrangian method using non-quadratic penalty functions

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OPSEARCH 2019年第2期56卷 390-408页

作者： Sanchez, M. D. Schuverdt, M. L. Univ Nacl La Plata Dept Math CONICET FCE CP 172 RA-1900 La Plata Buenos Aires Argentina

The purpose of the present paper is to study the global convergence of a practical Augmented Lagrangian model algorithm that considers non-quadratic Penalty-Lagrangian functions. We analyze the convergence of the model algorithm to points that satisfy the Karush-Kuhn-Tucker conditions and also the weak second-order necessary optimality condition. The generation scheme of the Penalty-Lagrangian functions includes the exponential penalty function and the logarithmic-barrier without using convex information.

关键词： nonlinear programming Augmented Lagrangian methods Global convergence Constraint qualifications Sequential optimality conditions

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Energy Consumption Optimization in Three-Machine Bernoulli Serial Lines 15

Energy Consumption Optimization in Three-Machine Bernoulli S...

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15th IEEE International Conference on Automation Science and Engineering (IEEE CASE)

作者： Yan, Chao-Bo Zhcng, Ziqian Xi An Jiao Tong Univ State Key Lab Mfg Syst Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Fac Elect & Informat Engn Xian 710049 Shaanxi Peoples R China

ISBN: (纸本)9781728103563

High energy consumption is detrimental for reducing manufacturing cost and improving competitiveness of manufacturing enterprises. In this paper, the problem of reducing energy consumption in a three-machine Bernoulli serial line is formulated and solved. Specifically, first, based on the aggregation method, structural characteristics of the optimization model are analyzed and thus, the problem is transformed;then, with the efficiency of the first machine fixed, based on the results of the energy consumption optimization model in the two-machine line, the optimization model is further analyzed and solved;finally, the property of the objective function with respect to the efficiency of the first machine is analyzed and based on the property, an algorithm is designed to solve the energy consumption optimization problem in the three-machine Bernoulli serial line.

关键词： Production rate nonlinear programming aggregation method monotonicity

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