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Continuous Robust control for Two-Dimensional Airfoils with Leading- and Trailing-Edge Flaps

JOURNAL OF GUIDANCE control AND DYNAMICS 2012年第2期35卷 510-519页

作者： Wang, Z. Behal, A. Marzocca, P. Univ Cent Florida Dept Elect Engn & Comp Sci Orlando FL 32826 USA Clarkson Univ Dept Elect Engn Comp Sci & NanoSci Technol Ctr Potsdam NY 13699 USA

In this paper, a class of multi-input/multi-output aeroelastic systems with unstructured nonlinear uncerta inty is considered. By using leading- and trailing-edge control surface actuations, a continuous robust controller is proposed to suppress the aeroelastic vibrations of a nonlinear wing-section model with plunging and pitching degrees of freedom. Under a mild restriction that the system uncertainties are second-order differentiable, the control design yields a semiglobal asymptotic stability result, leading to rapid suppression of the plunging and pitching motions. Numerical simulation results demonstrate the performance of the multi-input/multi-output continuous robust control toward suppressing aeroelastic vibration and limit cycle oscillations at pre- and postflutter flight speed regimes, even in the presence of bounded unknown external disturbance.

关键词： adaptive control algorithm Trailing Edge Flap Two Dimensional Airfoil adaptive Output Feedback control Aeroservoelastic Stability Aerodynamic Moments Angle of Attack control algorithm control Surfaces Neural Networks

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Single-Input/Single-Output adaptive Flutter Suppression of a Three-Dimensional Aeroelastic System

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JOURNAL OF GUIDANCE control AND DYNAMICS 2012年第2期35卷 659-665页

作者： Huang, Rui Hu, Haiyan Zhao, Yonghui Nanjing Univ Aeronaut & Astronaut Inst Vibrat Engn Res State Key Lab Mech & Control Mech Syst Nanjing 210016 Peoples R China

AEROELASTIC effects induced by the interaction of unsteady aerodynamics and structural dynamics are an extremely important concern in aircraft design. Among the aeroelastic effects, flutters and limit-cycle oscillations (LCO) are the critical constraints on the performance of an aircraft. Although a possible flutter or LCO can be suppressed via many conventional controls, such as classical single-input/single-output (SISO) feedback controls [1] and linear quadratic Gaussian (LQG) control [2], it is not easy to synthesize an efficient control scheme to suppress an aeroelastic instability because of parameter uncertainties caused by inaccurate computation of the aerodynamics and/or structural modes, as well as varying configurations. Therefore, it is necessary to develop an adaptive control to suppress the instability of an aeroelastic system with parameter uncertainties.

关键词： Aeroelastic Models Single Input Single Output adaptive control algorithm Linear Quadratic Gaussian Low Speed Wind Tunnel Finite Element Modeling adaptive Output Feedback control Aerodynamic Configurations Conjugate Gradient algorithm control Surfaces

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Model-Free control Design for Multi-Input Multi-Output Aeroelastic System Subject to External Disturbance

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JOURNAL OF GUIDANCE control AND DYNAMICS 2011年第2期34卷 446-458页

作者： Wang, Z. Behal, A. Marzocca, P. Univ Cent Florida Dept EECS Orlando FL 32826 USA Univ Cent Florida NanoSci Technol Ctr Orlando FL 32826 USA Clarkson Univ Potsdam NY 13699 USA

In this paper, a class of aeroelastic systems with an unmodeled nonlinearity and external disturbance is considered. By using leading- and trailing-edge control surface actuations, a full-state feedforward/feedback controller is designed to suppress the aeroelastic vibrations of a nonlinear wing section subject to external disturbance. The full-state feedback control yields a uniformly ultimately bounded result for two-axis vibration suppression. With the restriction that only pitching and plunging displacements are measurable while their rates are not, a high-gain observer is used to modify the full-state feedback control design to an output feedback design. Simulation results demonstrate the efficacy of the multi-input multi-output control toward suppressing aeroelastic vibration and limit cycle oscillations occurring in pre and postflutter velocity regimes when the system is subjected to a variety of external disturbance signals. Comparisons are drawn with a previously designed adaptive multi-input multi-output controller.

关键词： Nonlinear Aeroelasticity adaptive control algorithm Feedback Linearization Neural Networks Aerodynamic Moments control Surfaces Vibration Suppression Angle of Attack Flight Envelope Structural Nonlinearities

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Nonlinear adaptive control algorithm for a multicomponent batch distillation column

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CHEMICAL ENGINEERING SCIENCE 2007年第4期62卷 1111-1124页

作者： Murlidhar, Gundale Mangesh Jana, Amiya Kumar Birla Inst Technol & Sci Dept Chem Engn Pilani 333031 Rajasthan India

In this article, a nonlinear adaptive control strategy is proposed for a multicomponent batch distillation column. The hybrid control scheme consists of a generic model controller (GMC) and a nonlinear adaptive state estimator (ASE). In the first part of the study, an adaptive observer is designed aiming to estimate the partially known parameters based on the measured compositions in the presence of process/predictor mismatch. The open-loop dynamic behavior of the developed ASE estimator is investigated under initialization error, disturbance, and uncertain parameters. In the subsequent part, the adaptive GMC-ASE controller (GMC control structure in conjunction with ASE estimator) has been synthesized for the example distillation column. A simulation-based comparative study has been conducted between the derived nonlinear GMC-ASE control algorithm and a gain-scheduled proportional integral (GSPI) law in terms of constant composition control. The proposed adaptive control scheme is shown to be quite promising due to the exponential error convergence capability of the ASE estimator in addition to the high-quality performance of the GMC controller. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： generic model controller adaptive state estimator adaptive control algorithm multicomponent batch distillation

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Online Aerodynamic Model Structure Selection and Parameter Estimation for Fault-Tolerant control

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JOURNAL OF GUIDANCE control AND DYNAMICS 2010年第3期33卷 707-723页

作者： Lombaerts, T. J. J. Van Oort, E. R. Chu, Q. P. Mulder, J. A. Joosten, D. A. Delft Univ Technol Control & Simulat Div Aerosp Software & Technol Inst NL-2600 GB Delft Netherlands Delft Univ Technol Delft Ctr Syst & Control NL-2600 GB Delft Netherlands

This paper describes a new recursive algorithm for the approximation of time-varying nonlinear aerodynamic models by means of a joint adaptive selection of the model structure and parameter estimation. This procedure is called adaptive recursive orthogonal least squares and is an extension and modification of the classical recursive orthogonal least-squares procedure. This algorithm is considered to be particularly useful for indirect fault-tolerant flight control, making use of model-based adaptive control routines. After the failure, a completely new aerodynamic model can be elaborated recursively with respect to structure, as well as parameter values. The performance of the identification algorithm is demonstrated on some simulation data sets.

关键词： adaptive control algorithm Recursive algorithm Flight control control Surfaces Calibrated Airspeed Angle of Attack Aerodynamic Properties GPS Angle of Sideslip Inertial Navigation System

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adaptive Feedforward control for Gust Load Alleviation

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JOURNAL OF GUIDANCE control AND DYNAMICS 2010年第3期33卷 862-872页

作者： Zeng, Jie Moulin, Boris de Callafon, Raymond Brenner, Martin J. ZONA Technol Inc Scottsdale AZ 85258 USA Univ Calif San Diego La Jolla CA 92093 USA NASA Dryden Flight Res Ctr Edwards AFB CA 93523 USA

In this paper, an adaptive feedforward control framework is proposed for the suppression of aircraft structural vibrations induced by gust perturbations to increase the resilience of the flight control law in the presence of the aeroelastic/aeroservoelastic interactions. Currently, aircraft with nonadaptive control laws usually include roll-off or notch filters to avoid aeroelastic/aeroservoelastic interactions. However, if changes in the aircraft configuration are significant, the frequencies of the flexible modes of the aircraft may be shifted, and the notch filters could become totally ineffective. With the proposed approach, the flexible modes can be consistently estimated in real time via a proven system-identification algorithm. The identified flexible modes information is used in the proposed adaptive feedforward control algorithm to adjust the parametrization of the basis functions in a feedforward controller. Along with the recursive least-squares estimate, the feedforward controller is adjusted, and the structural vibration of the aircraft induced by the gust perturbation can be largely suppressed. An F/A-18 active aeroelastic wing aeroelastic model with gust perturbation based on the linear aeroelastic solver formulation is developed as a test bed to demonstrate the proposed adaptive feedforward control algorithm.

关键词： adaptive control algorithm Aerodynamic Force Coefficients Aeroservoelastic Systems Vibration Suppression Aircraft Configurations control algorithm Active Aeroelastic Wing Flight control Law Frequency Response Functions Leading Edge Flap

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A permanent magnetic actuator with scheduled stroke curve for vacuum circuit breakers

A permanent magnetic actuator with scheduled stroke curve fo...

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24th International Symposium on Discharges and Electrical Insulation in Vacuum ISDEIV

作者： Huang Zhihui Duan Xiongying Zou Jiyan Chen Mingfan Dalian Univ Technol Sch Elect Engn Dalian 116024 Peoples R China

ISBN: (纸本)9781424483655

The load characteristics of vacuum circuit breakers (VCB) are very close to the output characteristics of permanent magnetic actuator (PMA). The combination of PMA and VCB facilitates the development of phase-controlled switching technology because of its controllability. The operation time dispersion of PMA is very small, but when the actuator is impacted by the change of environment or its components, its dispersion will be unfit for phase-controlled switching. A new type of actuator driving system for PMA was proposed, which was combined with sensors, embedded system and capacitor controlled by high-current power electronic devices. The iron core trajectory of PMA was measured by a displacement sensor and compared to a scheduled action curve, the environment temperature is from a temperature sensor and the current from a Hall current sensor, then compensation to displacement was made based on the adaptive control algorithm and history data in order to match the optimal stroke curve of vacuum circuit breakers. In different conditions, the test results show that the stroke curve was in keeping with the scheduled curve and the operating time dispersion of VCB meets the requirement. The new type actuator driving system can supply an easy-controlled, constant-operating-time execution unit to controlled switching.

关键词： Hall current sensor actuator driving system adaptive control adaptive control algorithm controllability displacement sensor electromagnetic actuators high-current power electronic devices permanent magnetic actuator permanent magnets phase-controlled switching technology scheduled stroke curve temperature sensor temperature sensors vacuum circuit breakers vacuum circuit breakers

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Forced Flame Response of Turbulent Liquid-Fueled Lean-Direct-Injection Combustion to Fuel Modulations

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JOURNAL OF PROPULSION AND POWER 2009年第6期25卷 1259-1271页

作者： Yi, Tongxun Santavicca, Domenic A. Penn State Univ Dept Mech & Nucl Engn University Pk PA 16802 USA

Reported are the forced flame responses of a turbulent, liquid-fueled, swirl-stabilized, lean-direct-injection combustor to fuel modulations. Fuel modulations are achieved using a motor-driven, high-frequency, rotary fuel valve specially designed for this experiment. This valve is capable of fuel modulations up to 1 kHz. The instantaneous fuel How rate out of a fuel injector is accurately determined from pressure measurements at one or two locations upstream of the fuel nozzle. Linear flame responses are obtained with small-amplitude fuel modulations, typically below 2.0% of the mean fuel How rate, about 60 Hz below the acoustic resonant frequencies. The invariance in the flame transfer functions to the fuel modulation amplitude suggests that the derived flame transfer functions are linear and that the induced heat release rate oscillations mainly respond to variations in the instantaneous fuel flow rate rather than in the droplet size and distribution. Flame transfer functions at different air flow rates, equivalence ratios, and preheat temperature are examined. With fuel modulations around the acoustic resonant frequencies, forcing-induced acoustic feedback on heat release responses cannot be ignored, and the measured flame transfer functions are no longer open-loop and linear. The nonlinearity in the forced flame responses is significantly affected by acoustic damping. Extinction and entrainment of self-excited combustion oscillations by fuel modulations at the approach of the acoustic resonant frequencies are observed. Self-excited combustion oscillations can be diminished by increasing the amount of fuel modulations. Applications of the flame transfer functions to modeling and control of combustion instability and lean blowout for both liquid-fueled and gas-fueled combustion are discussed.

关键词： Liquid Fuels Fuels Lean Premixed Combustion Planar Laser Induced Fluorescence Resonant Frequencies Swirl Stabilized Combustor Combustion Chambers Fuel Injector adaptive control algorithm Fuel Valve

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Indirect robust adaptive fault-tolerant control for attitude tracking of spacecraft

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JOURNAL OF GUIDANCE control AND DYNAMICS 2008年第5期31卷 1456-1463页

作者： Cai, Wenchuan Liao, X. H. Song, Y. D. N Carolina Agr & Tech State Univ Ctr Cooperat Syst Greensboro NC 27411 USA Volvo N Amer Inc Greensboro NC 27455 USA N Carolina Agr & Tech State Univ Dept Elect & Comp Engn Greensboro NC 27411 USA Natl Inst Aerosp Hampton VA 23666 USA

Reliable and cost-effective control of spacecraft should account for modeling uncertainties, unexpected disturbances,, subsystem failures, and limited resources simultaneously. This paper presents an indirect (nonregressor-based) approach to attitude tracking control of spacecraft. It is shown that the control algorithms developed are not only robust against external disturbances and adaptive to unknown and time-varying mass/inertia properties, but also able to accommodate actuator failures under limited thrusts. All are achieved with inexpensive online computations (a feature of practical importance in reducing the usage of onboard resources in terms of computing power and memory size). Furthermore, this method is user/designer friendly in that it does not involve a time-consuming design procedure and demands little redesigning or reprogramming during vehicle operation. The benefits of the proposed control method are analytically authenticated and also validated via simulation study.

关键词： Attitude Tracking Rigid Spacecraft Actuators control algorithm Onboard Computing Attitude Dynamics adaptive control algorithm Variable Structure control Quaternions Numerical Simulation

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Application of real-time adaptive control algorithm in adaptive optics system

Application of real-time adaptive control algorithm in adapt...

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Conference on adaptive Optics and Applications III

作者： Li, XY Meng, L Jiang, WH Chinese Acad Sci Inst Opt & Elect Lab Adapt Opt Chengdu 610209 Peoples R China

ISBN: (纸本)0819455946

A kind of real-time adaptive control (RTAC) algorithm that can be put into practice in the feed-back close loop AO system was introduced in this paper. The RTAC algorithm, doesn't like the traditional control algorithm, considered the effect of atmospheric turbulence and the measurement noise together with the dynamic characteristics of the AO system. The parameters of controller can be modified during iterative calculation through the RTAC algorithm. The RTAC algorithm can adapt to the changes of work conditions to keep achieve optimal control performance. The theory of the RTAC algorithm will be discussed. The computer simulation and the experiment results on a modular adaptive optics experiment system with the RTAC algorithm will be discussed.

关键词： adaptive optics system adaptive control algorithm real-time measurement noise

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