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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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Performance Optimization and Guidance of a Low-Altitude Skid-To-Turn Vehicle. Part I: Performance Optimization

Performance Optimization and Guidance of a Low-Altitude Skid...

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AIAA Science and Technology (SciTech) Forum and Exposition

作者： Dennis, Miriam E. Rao, Anil, V Univ Florida Dept Mech & Aerosp Engn Gainesville FL 32611 USA

ISBN: (数字)9781624105784

ISBN: (纸本)9781624105784

The problem of air-to-surface trajectory optimization for a low-altitude skid-to-turn vehicle is considered. The objective is for the vehicle to move level at a low altitude for as long as possible and performa rapid bunt (negative sensed-acceleration load)maneuver near the final time in order to attain terminal target conditions. The vehicle is modeled as a point mass in motion over a flat Earth, and the vehicle is controlled using thrust magnitude, angle of attack, and sideslip angle. The trajectory optimization problemis posed as a two-phase optimal control problem using a weighted objective function. The work described in this paper is the first part of a two-part sequence on trajectory optimization and guidance of a skid-to-turn vehicle. In both cases, the objective is to minimize the time taken by the vehicle to complete a bunt maneuver subject to the following constraints: dynamic, boundary, state, path, and interior-point event constraints. In the first part of this two-part study, the performance of the vehicle is assessed. In particular, the key features of the optimal reference trajectories and controls are provided. The results of this study identify that as greater weight is placed on minimizing the height of the bunt maneuver or as the maximum altitude constraint is raised, the time of the bunt maneuver decreases and the time of the problem solution increases. Also, the results of this study identify that as the allowable crossrange of the vehicle is reduced, the time and height of the bunt maneuver increases and the time of the problem solution decreases.

关键词： Aerodynamic Force Trajectory Optimization nonlinear programming Numerical Integration Control Guidance Air to Surface Missiles Flight Path Angle Mesh Generation Angle of Attack Spline Interpolation

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Incorporating stochastics into optimal collision avoidance problems using superquadrics

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Journal of Air Transportation 2020年第2期28卷 65-69页

作者： Smith, Nathan E. Cobb, Richard G. Baker, William P. Air Force Institute of Technology Wright-Patterson Air Force Base U.S. Air Force Ohio45433 United States Department of Aeronautics & Astronautics Air Force Institute of Technology Wright-Patterson Air Force Base Ohio45433 United States Department of Mathematics & Statistics Air Force Institute of Technology Wright-Patterson Air Force Base Ohio45433 United States

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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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Exact Computation of Delay Margin by PID Control: It Suffices to Solve a Unimodal Problem! 38

Exact Computation of Delay Margin by PID Control: It Suffice...

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38th Chinese Control Conference (CCC)

作者： Chen, Jianqi Ma, Dan Xu, Yong Chen, Jie City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong Peoples R China Northeastern Univ Coll Informat Sci & Engn State Key Lab Synthet Automat Proc Ind Shenyang Peoples R China Guangdong Univ Technol Sch Automat Guangdong Prov Key Lab Intelligent Decis & Cooper Guangzhou Peoples R China

ISBN: (纸本)9789881563972

In this paper we study delay robustness of PID controllers in stabilizing systems containing uncertain, variable delays. We consider second-order unstable systems and seek analytical characterization and exact computation of the PID delay margin, where by PID delay margin we mean the maximal range of delay values within which the system can be robustly stabilized by a MD controller. Our contribution is threefold. First, we show that the delay margin achieved by PID control coincides with that by PD controllers. Second. we show that other than helping stabilize the delay-free part of a plant, the proportional control contributes no action to increase the delay margin. Finally, we show that the PID delay margin can be computed efficiently by solving a unimodal problem, that is, a univariate optimization problem that admits a unique maximum and hence is a convex optimization problem in one variable. This unimodal problem is one of pseudo-concave optimization and hence can be solved using standard convex optimization or gradient-based methods. As such, from a computational perspective, the ND delay margin problem is completely resolved in this paper! The results not only insure that the PIE) delay margin problem be readily solvable, but also provide fundamental conceptual insights into the PID control of delay systems, and analytical justifications to long-held engineering intuitions and heuristics, thus lending useful guidelines in the tuning and analytical design of PID controllers.

关键词： Delay margin robust stabilization PID controller uncertain time delay nonlinear programming pseudo-concavity

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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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Optimization of line of balance scheduling considering work interruption

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INTERNATIONAL JOURNAL OF CONSTRUCTION MANAGEMENT 2019年第2期22卷 305-316页

作者： Ammar, Mohammad A. Tanta Univ Fac Engn Struct Engn Dept Tanta Egypt

Line of Balance (LOB) technique is frequently used for scheduling typical repetitive projects, in which crew work continuity is maintained and multiple crews per activity is allowed. Allowing work interruptions intentionally;however, might enhance project performance. The determination of optimum interruption values and the repetitive units at which work interruptions are permitted are challenging problems. Optimization problems have been traditionally solved by two approaches;heuristic methods and optimization techniques. Although heuristic methods can handle large-size projects, they do not guarantee optimal solutions. In this paper, a mathematical optimization model is developed to optimize project duration in LOB scheduling considering work interruption. Constant activity progress rate is assumed, work continuity is maintained, and planned work interruptions are allowed. Optimum interruption values and the activities' interrupted units are determined. Details of model formulation are illustrated by an example project. The developed model is then validated by a case study project and the principal conclusions are drawn. Although work continuity is an essential requirement in LOB scheduling, allowing for planned work interruption enhances project performance. The model can be used to study the project under various scenarios and the project manager can select the best alternative that meets his/her needs.

关键词： Construction management repetitive projects line of balance work interruptions optimization nonlinear programming

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Optimizing the use of renewable energy sources in the energy mix of Hungary 17

Optimizing the use of renewable energy sources in the energy...

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17th IEEE World Symposium on Applied Machine Intelligence and Informatics (SAMI)

作者： Borcsok, Endre Gerse, Agnes Fulop, Janos Obuda Univ Hungarian Acad Sci Energy Res Ctr Budapest Hungary Hungarian Acad Sci Energy Res Ctr Budapest Hungary Obuda Univ Hungarian Acad Sci Inst Comp Sci & Control Budapest Hungary

ISBN: (纸本)9781728102504

This paper reports short-term energy scenarios for the heat and electricity generation in Hungary, considering the recent developments in the overall European and national energy policy framework promoting the use of energy from renewable energy sources. Focusing on the heating and electricity sectors, a methodology for portfolio optimization has been developed in order to identify the optimal energy mix in terms of technology alternatives and energy sources. As a base case, a pure economic assessment was done considering the investment costs, the net present values and the operation and maintenance ( O&M) costs. The optimization was extended by involving additional factors in the next steps, adding carbon prices and the external costs of the environmental and human health (physiological) impacts to the model. An aggregate approach is applied to reduce complexity;national aggregation was chosen for the electricity sector while building typological groups and local geographical entities were defined for the heating sector. The level of saturation of different technology alternatives in the market is modeled in the proposed methodology, as well. The mathematical formulation of the optimization problem was given as a non-linear case of the distribution problem.

关键词： optimal energy mix nonlinear programming distribution problem

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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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