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Feasible flight paths for cooperative generation of a phantom radar track

JOURNAL OF GUIDANCE control AND DYNAMICS 2006年第3期29卷 653-661页

作者： Purvis, Keith B. Chandler, Phillip R. Pachter, Meir Univ Calif Santa Barbara Dept Mech & Environm Engn Santa Barbara CA 93106 USA USAF Res Lab VACA Wright Patterson AFB OH 45433 USA USAF Inst Technol Dept Elect & Comp Engn Wright Patterson AFB OH 45433 USA

Electronic attack on air defense radar networks by electronic combat air vehicles (ECAVs) is considered. The scope of the attack is the creation of a coherent phantom track in two dimensions-range and azimuth-by a team of cooperatively controlled ECAVs, each capable of intercepting and sending delayed returns of radar pulses. It is first shown that assuming constant speeds for the phantom track and ECAVs severely restricts where the ECAVs can fly. Accordingly, general dynamic and spatial limitations on an ECAV are developed given ranges on the ECAV speed, phantom track speed, and ECAV region of antenna operation;six dynamical systems are also constructed for simulating feasible ECAV trajectories to test the analytical limitations. This theory is applied to construct detailed flyable ranges for an ECAV generating a straight and a circular phantom track, separately. Based on distilling the results, generalized bounds are presented-independent of the phantom track type-for the initial conditions and time-dependent flyable ranges of a team of ECAVs. These bounds are then used with coordination functions to informally solve an illustrative decentralized cooperative control problem in which the ECAV team seeks an optimal straight phantom track to minimize their bounds-dependent aggregate cost.

关键词： RADAR Antennas Combat Air Vehicle Inverse Problems Heading Angle Air Vehicle Electronic Warfare control algorithm Fuel Consumption Aviation

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Understanding the combustion mode transition from CDC to RCCI and RCCI to CDC - An experimental approach

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ENERGY CONVERSION AND MANAGEMENT 2022年 270卷

作者： Subramani, Arun Kumar Duraisamy, Ganesh Govindan, Nagarajan Krishnasamy, Anand Anna Univ Internal Combust Engn Div Dept Mech Engn Coll Engn Guindy Campus Chennai 600025 Tamil Nadu India Indian Inst Technol Madras Dept Mech Engn IC Engines Lab Chennai 600036 Tamil Nadu India

This article presents an experimental understanding of combustion mode transition from conventional diesel combustion (CDC) mode to reactivity-controlled compression ignition (RCCI) combustion mode. In the current study the variations in combustion, performance, and emissions during the mode transition were investigated and accordingly a dual fuel control algorithm for achieving smooth transition between CDC and RCCI com-bustion modes was developed. Experimental data are presented for CDC with diesel and RCCI with Gasoline/ Diesel at 1600 rev/min, 25 N.m torque only, considering the data size and ease of understanding the mode transition. Nine steps have been adopted to switch from CDC to RCCI combustion mode. The operating variables such as number of diesel injections, injected diesel mass between the injections, gasoline energy fraction, diesel start of injection, and exhaust gas recirculation (EGR) flow rate have been altered to switch from CDC to RCCI. Changes in combustion, performance, and emissions have been recorded and analyzed at each operating variable to determine the optimal path for smooth combustion mode transition. A similar approach has been extended to medium and high loads to obtain the optimal path. Finally, all the optimal paths have been collated to develop calibrated maps for operating the chosen test engine from CDC to RCCI and RCCI to CDC modes smoothly.

关键词： Mode transition RCCI CDC control algorithm High efficiency CA50

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Optimized TRIAD algorithm for attitude determination

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JOURNAL OF GUIDANCE control AND DYNAMICS 1997年第1期20卷 208-211页

作者： BarItzhack, IY Harman, RR NASA GODDARD SPACE FLIGHT CTRFLIGHT MECH BRANCHGREENBELTMD 20771

When the components of two abstract vectors are given in two different coordinate systems, it is possible to find the orientation difference between the two systems. TRIAD is an algorithm that finds the transformation matrix from one coordinate system to the other. The accuracy of a vector-measuring device is quantified by the standard deviation of its errors. The vector measured by a star tracker is assigned a standard deviation to the TRIAD computed attitude matrix that corresponds to the standard anchor vector used in computing the matrix. The optimized TRIAD version alternately uses the two vectors as reference and computes the relative accuracy of the two vectors, thus, yielding a more accurate average result compared to the original algorithm.

关键词： Quaternions Power Spectral Density Computing Target Spacecraft Propulsion System Star Tracker Magnetometers Strapdown Inertial Navigation System control algorithm Satellite Maneuvers

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Analysis of bending vibration of rectangular plates using two-dimensional plate modes

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JOURNAL OF AIRCRAFT 2005年第2期42卷 542-550页

作者： Wang, G Wereley, NM Chang, DC Univ Maryland Smart Struct Lab Alfred Gessow Rotorcraft Ctr Dept Aerosp Engn College Pk MD 20742 USA Georgetown Univ Ctr Math Sci Dept Math Washington DC 20057 USA

A higher order assumed modes (Ritz) method is developed for rectangular plate analysis using two-dimensional plate mode shape functions. These two-dimensional plate mode shape functions were determined using the extended Kantorovich-Krylov method. The rectangular plate is assumed isotropic and uniform, and has each edge of its span (root and tip) clamped and remaining edges free (clamped-free-clamped-free boundary conditions). Natural frequencies, mode shape functions, and frequency responses of the plate were calculated and compared to the results of traditional analysis using one-dimensional beam modes to approximate plate modes in both x and y directions. The updated two-dimensional plate mode shape functions substantially reduce the computational cost compared to the case of using one-dimensional beam mode shape functions. Fewer modes are needed in the proposed method to yield the same accuracy. Experiments were conducted to validate our predictions and the data agree with our predictions.

关键词： Vibration Isolation Shape Functions Frequency Response Functions Aspect Ratio Poisson's Ratio MATLAB Total Energy Boundary Value Problems control algorithm Galerkin Method

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IDENTIFICATION OF TIME-VARYING STRUCTURAL DYNAMIC-SYSTEMS - AN ARTIFICIAL-INTELLIGENCE APPROACH

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AIAA JOURNAL 1992年第5期30卷 1371-1382页

作者： GLASS, BJ HANAGUD, S GEORGIA INST TECHNOL ATLANTA GA 30332 USA

An application of the artificial intelligence-derived methodologies of heuristic search and object-oriented programming to the problem of identifying the form of the model and the associated parameters of a time-varying structural dynamic system is presented in this paper. Possible model variations due to changes in boundary conditions or configurations of a structure are organized into a taxonomy of models, and a variant of best-first search is used to identify the model whose simulated response best matches that of the current physical structure. Simulated model responses are verified experimentally. An output-error approach is used in a discontinuous model space, and an equation-error approach is used in the parameter space. The advantages of the AI methods used, compared with conventional programming techniques for implementing knowledge structuring and inheritance, are discussed. Convergence conditions and example problems have been discussed. In the example problem, both the time-varying model and its new parameters have been identified when changes occur.

关键词： Natural Language Processing Finite Element Analysis Structural Dynamics Simply Supported Beams FORTRAN Distributed Parameter System control algorithm Structural Modeling Dynamic Analysis Optimal control

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MPPT based on a novel load segmentations structure for PV applications

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AIN SHAMS ENGINEERING JOURNAL 2023年第4期14卷

作者： Eldessouky, Ahmed Samir Mahmoud, I. M. Abdel-Salam, T. S. British Univ Egypt Fac Energy & Environm Engn Renewable Energy Dept Cairo 11837 Egypt Ain Shams Univ Fac Engn Elect Power & Machine Dept Cairo 11571 Egypt

The main disadvantage of photovoltaic (PV) systems is the mismatch between load and generation profiles. To overcome this disadvantage, it is either connected to battery bank or connected to the utility grid via inverters. While the battery choice is expensive and produces contaminating elements, the grid -connected mode is the most common choice. However, the inverters represent high percentage of the system cost that affect its potential to be a competitive economic replacement for other conventional energy sources. In addition, interfacing different users to the grid using inverters increase the total har-monics distortion (THD) and reduce the power quality of the grid. Moreover, exporting surplus energy generated from PV during off-peak periods with lower tariff reduces the economic effectiveness of PV systems. This paper proposes a segmented structure of the electric thermal loads with control algorithm that can achieve the MPPT objectives with no need for inverters. Moreover, with the right selection of PV size, it is possible to be locally consumed each generated kWh of energy without the need to export any to the main grid with low tariff. The segments of the electric thermal load that satisfy the MPP condition are connected to the PV while the rest segments are connected to main grid via set of electromagnetic relays. A simulation of the proposed structure and control algorithm was performed. The results shows that accurate MPPT was achieved according to the number of load segments. To increase the accuracy, the number of load segments should be increased.(c) 2022 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Ain Shams Uni-versity. This is an open access article under the CC BY-NC-ND license (http://***/licenses/ by-nc-nd/4.0/).

关键词： MPPT Load segments PV control algorithm DC DC Converter

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TRAJECTORY OPTIMIZATION USING PARALLEL SHOOTING METHOD ON PARALLEL COMPUTER

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JOURNAL OF GUIDANCE control AND DYNAMICS 1995年第2期18卷 377-379页

作者： WIRTHMAN, DJ PARK, SY VADALI, SR Texas A&M University College Station Texas 77843

The efficiency of a parallel shooting method on a parallel computer for solving a variety of optimal control guidance problems is studied. Several examples are considered to demonstrate that a speedup of nearly 7 to 1 is achieved with the use of 16 processors. It is suggested that further improvements in performance can be achieved by parallelizing in the state domain.

关键词： Central Processing Unit Trajectory Optimization Angle of Attack Aerodynamic Coefficients Nonlinear Programming Aerospace Engineering Advanced Launch System Dynamic Pressure control Guidance control algorithm

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Differentiator-free nonlinear proportional-integral controllers for Rigid-body attitude stabilization

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JOURNAL OF GUIDANCE control AND DYNAMICS 2004年第6期27卷 1092-1096页

作者： Subbarao, K Akella, MR Univ Texas Dept Mech & Aerosp Engn Arlington TX 76019 USA Univ Texas Dept Aerosp Engn & Engn Mech Austin TX 78712 USA

A new class of angular velocity-free attitude stabilization controllers that can be viewed as generalizations of the existing passivity-based control algorithms in the sense of providing an additional provision for integral feedback action was designed. Global asymptotic stability for the full state of the rigid-body rotational motion was demonstrated when the external disturbances are absent. The disturbance rejection aspect was illustrated using a linearized setting of the problem. The controller structure includes a low-pass filter state that is derived without explicit differentiation of attitude to synthesize angular velocity-like signals.

关键词： Proportional Integral controller Attitude Stabilization Quaternions Full State Feedback Guidance Laws Numerical Simulation Attitude Kinematics Relative Kinematics Variable Structure control control algorithm

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Stochastic and Dynamic Routing Problems for Multiple Uninhabited Aerial Vehicles

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JOURNAL OF GUIDANCE control AND DYNAMICS 2009年第4期32卷 1152-1166页

作者： Enright, John J. Savla, Ketan Frazzoli, Emilio Bullo, Francesco MIT Dept Aeronaut & Astronaut Informat & Decis Syst Lab Cambridge MA 02139 USA Univ Calif Santa Barbara Dept Mech Engn Santa Barbara CA 93106 USA Univ Calif Santa Barbara Ctr Control Dynam Syst & Computat Santa Barbara CA 93106 USA

Consider a routing problem for a team of vehicles in the plane: target points appear randomly over time in a bounded environment and must be visited by one of the vehicles. It is desired to minimize the expected system time for the targets, that is, the expected time elapsed between the appearance of a target point and the instant it is visited. In this paper, such a routing problem is considered fora team of uninhabited aerial vehicles, modeled as vehicles moving with constant forward speed along paths of bounded curvature. Three algorithms are presented, each designed for a distinct set of operating conditions. Each is proven to provide a system time within a constant factor of the optimal when operating under the appropriate conditions. It is shown that the optimal routing policy depends on problem parameters such as the workload per vehicle and the vehicle density in the environment. Finally, there is discussion of a phase transition between two of the policies as the problem parameters are varied. In particular, for the case in which target,;appear sporadically, a dimensionless parameter is identified which completely captures this phase transition and an estimate of the critical value of the-parameter is provided.

关键词： Uninhabited Aerial Vehicle Air Traffic control Robotics Weapon Target Assignment High Altitude Aircraft Numerical Optimization Aircraft Kinematics Multi Agent System control algorithm Motion Planning

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QUATERNION FEEDBACK REGULATOR FOR SPACECRAFT EIGENAXIS ROTATIONS

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JOURNAL OF GUIDANCE control AND DYNAMICS 1989年第3期12卷 375-380页

作者： WIE, B WEISS, H ARAPOSTATHIS, A UNIV TEXAS DEPT ELECT & COMP ENGNAUSTINTX 78712

A quaternion feedback regulator is developed for spacecraft eigenaxis rotational maneuvers. The Euler's eigenaxisrotation that provides the shortest angular path between two orientations is considered as an “optimal” *** control algorithm basically consists of linear feedback of error quaternions and body rates, and includesdecoupling control torque that counteracts the natural gyroscopic coupling torque. But, in some cases with smallangular rates, the gyroscopic decoupling control is not necessary for eigenaxis rotations. It is shown that large-angle, rest-to-rest maneuver about the Euler's eigenaxis can be simply achieved by a proper selection of feedback gainmatrices of the quaternion feedback regulator. Furthermore, previous results in quaternion feedback stability analysisbased on the Lyapunov method are significantly extended. Robustness of the globally stable, quaternion feedbackregulator to spacecraft inertia matrix uncertainty is also discussed. Simulation results show that a proper selectionof the quaternion feedback regulator gains provides near-eigenaxis rotation, even in the presence of initial body rateand inertia matrix uncertainty. © 1989 American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Rigid Spacecraft Quaternions Gyroscopic Couple control algorithm Closed Loop System Nonlinear Feedback Attitude control System Reaction Wheels Optimal control Large Angle Maneuver

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