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Simulation of adaptive optics for the Vacuum Tower Telescope

EXPERIMENTAL ASTRONOMY 2006年第2期21卷 87-99页

作者： Enmark, Anita Berkefeld, Thomas von der Luhe, Oskar Andersen, Torben Lund Observ SE-22100 Lund Sweden

A simulation model of the adaptive optics of the German Vacuum Tower Telescope (VTT), Observatorio del Teide, Tenerifes presented. The model uses modules from the integrated model of the Euro50 extremely large telescope, and includes submodels of a Shack-Hartmann wavefront sensor, a de-formable mirror, a tip-tilt mirror, high-voltage amplifier low-pass filters, a reconstructor and a controller. We investigate the impact on the closed loop bandwidth of changes in controller configuration and certain system parameters, such as low pass filter bandwidth and camera integration and readout time. control strategies were tested on simple models before implementation on the full VTT model. Using the models, different control strategies are compared.

关键词： adaptive optics simulation control algorithms solar telescope modelling

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A Network for Agricultural Management Systems: The Communications and control Platforms

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IFAC Proceedings Volumes 1998年第12期31卷 319-324页

作者： Carlos Serôdio J. Boaventura Cunha Raul Morais Carlos Couto João Monteiro Grupo de Comunicações - Universidade de Trás-os-Montes e Alto Douro 5000 Vila Real Portugal Grupo de Controlo e Instrumentação - Universidade de Trás-os-Montes e Alto Douro 5000 Vila Real Portugal Depanamento de Electrónica Industrial - Universidade do Minho 4700 Braga Portugal

Greenhouse control computers are an essential part of modem greenhouse operation. Climate, irrigation and nutrient supply must be controlled, in an economically way, to produce the best crop conditions. Current research on CO 2 enrichment and optimal growth strategies implies the use of powerful tools, either based on hardware or software. This paper describes the implementation of a distributed data acquisition and control system for computerised agricultural management systems. To accomplish with the emergent and future tendencies in this area the network uses different communications platforms to achieve low-cost, flexibility, and functionality. The techniques and tools, that provide to the user a transparent, friendly and intuitive Graphical User Interface will be also presented.

关键词： Agriculture Automation control algorithms Models Network topologies

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OPTIMAL-control OF NONLINEAR STRUCTURES

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JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME 1988年第4期55卷 931-938页

作者： YANG, JN LONG, FX WONG, D GEORGE WASHINGTON UNIV DEPT CIVIL MECH & ENVIRONM ENGNWASHINGTONDC 20052

Three optimal control algorithms are proposed for reducing oscillations of flexible nonlinear structures subjected to general stochastic dynamic loads, such as earthquakes, waves, winds, etc. The optimal control forces are determined analytically by minimizing a time-dependent quadratic performance index, and nonlinear equations of motion are solved using the Wilson-θ numerical procedures. The optimal control algorithms developed for applications to nonlinear structures are referred to as the instantaneous optimal control algorithms, including the instantaneous optimal open-loop control algorithm, instantaneous optimal closed-loop control algorithm, and instantaneous optimal closed-open-loop control algorithm. These optimal algorithms are computationally efficient and suitable for on-line implementation of active control systems to realistic nonlinear structures. Numerical examples are worked out to demonstrate the applications of these optimal control algorithms to nonlinear structures. In particular, control of structures undergoing inelastic deformations under strong earthquake excitations are illustrated. The advantage of using combined passive/active control systems is also demonstrated.

关键词： Optimal control algorithms control algorithms Earthquakes control systems Motion Stress Waves Nonlinear equations Oscillations

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Review of control technologies for floating offshore wind turbines

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RENEWABLE & SUSTAINABLE ENERGY REVIEWS 2022年第0期167卷

作者： Lopez-Queija, Javier Robles, Eider Jugo, Josu Alonso-Quesada, Santiago Basque Res & Technol Alliance BRTA TECNALIA Parque Tecnol Bizkaia Astondo BideaEdificio 700 E-48160 Derio Bizkaia Spain Univ Basque Country UPV EHU Mech Engn Dept Bilbao 48013 Spain Univ Basque Country UPV EHU Automat & Syst Engn Dept Bilbao 48013 Spain Univ Basque Country UPV EHU Elect & Elect Dept Leioa 48940 Spain

Floating offshore wind growth places the industry development close to commercial scale. However, the harsh environment with strong winds, waves, and currents, together with the increasing size of wind turbines and floater motions could affect power production and reduce system lifetime due to fatigue loads. In any case, operating the wind turbine close to the optimum efficiency value guaranteeing its reliability through fatigue load reduction could be achieved with a proper control strategy. This paper proposes a critical review of the state-of-art of floating wind turbine control technologies, discussing the advantages and drawbacks of the most used control algorithms and classifying them, to summarize the future trends of the research.

关键词： Floating offshore wind turbines Wind turbine control Wind energy Structural control control algorithms

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PREVIEW control FOR VEHICLE LATERAL GUIDANCE IN HIGHWAY AUTOMATION

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JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND control-TRANSACTIONS OF THE ASME 1993年第4期115卷 679-686页

作者： PENG, H TOMIZUKA, M UNIV CALIF BERKELEY DEPT MECH ENGNBERKELEYCA 94720

The continuous time deterministic optimal preview control algorithm is applied to the lateral guidance of a vehicle for an automated highway. In the lateral guidance problem, the front wheel steering angle of the vehicle is controlled so that the vehicle follows the center for a lane with small tracking error and maintains good ride quality simultaneously. A preview control algorithm is obtained by minimizing a quadratic performance index which includes terms representing the passenger ride quality as well as the lateral tracking error, each of these terms is multiplied by a frequency dependent weight. This design method is known as a frequency shaped linear quadratic (FSLQ) optimal control approach. It permits incorporating frequency domain design specifications such as high frequency robustness and ride quality in the optimal controller design. It is shown that the optimal preview control law consists of a feedback control term and two feedforward control terms. The feedback term is exactly the same as that of traditional LQ control algorithm. The feedforward preview control action significantly improves the tracking performance and ride quality. Frequency-domain analyses, as well as numerical simulation results, show the improvements achieved by using the preview control algorithm in both the frequency and time domains.

关键词： Errors Weight (Mass) Frequency-domain analysis Vehicles control algorithms Design Feedforward control Robustness Highways Wheels Design methodology Optimal control control equipment Feedback Computer simulation

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NEAR-OPTIMAL control OF A BILINEAR, SOLAR-ASSISTED HEAT-PUMP SYSTEM

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JOURNAL OF SOLAR ENERGY ENGINEERING-TRANSACTIONS OF THE ASME 1987年第4期109卷 259-266页

作者： LE, H ZAHEERUDDIN, M GOURISHANKAR, V RINK, R UNIV ALBERTA DEPT ELECT ENGNEDMONTON T6G 2E1ALBERTACANADA

A system consisting of a flat-plate solar collector, two heat storage tanks, a heat pump, and all necessary minor components is considered. For each major component a bilinear mathematical model is developed. The system control problem is divided into steady-state and dynamic cases, and the optimal steady-state solution is found. Based on this result a suboptimal dynamic control algorithm is given and is shown to give locally stable and near optimal performance. Results of a simulation study, comparing seasonal performance of the suboptimal system with that of the conventionally-controlled system are given.

关键词： Solar energy Heat pumps Steady state control algorithms Flat plates Heat storage Simulation Solar collectors

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Intelligent methodology for sensing, modeling and control of pulsed GTAW: Part I - Bead-on-plate welding

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WELDING JOURNAL 2000年第6期79卷 151S-163S页

作者： Chen, SB Lou, YJ Wu, L Zhao, DB Harbin Inst Technol Natl Key Lab Adv Welding Prod Technol Harbin 150006 Peoples R China

This study addresses intelligent techniques for Fulfilling quality control of bead-on-plate welding. A new visual double-sided sensing system capable of imaging the weld pool topside and backside simultaneously in a frame was provided to determine the weld pool geometry parameters. The imaging principle was analyzed with spectrum distribution, in which the weld pool was illuminated by are light emission to receive a clear image under base current. Double-sided size parameters describing weld pool geometry were defined and determined in real time with the developed image processing algorithm. The influences of welding parameters such as pulse duty ratio and travel speed on weld bead geometry were identified by step response. Based on the analysis, a neural network model of the dynamic process was established for predicting the backside width with the welding parameters and topside size parameters. The simulation results indicated the accuracy of the model, and the characteristics of the welding process were analyzed carefully. Aiming at the bead-on-plate pulsed GTAW process, conventional and intelligent control methods of single input and single output were investigated, and the neuron self-learning PSD control was verified with better performance for practical application through comparisons.

关键词： bead-on-plate welding control algorithms computer vision double-sided sensing fuzzy logic neural network model pulsed GTAW

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Implementation of sensory feedback and trajectory tracking in active telemanipulation systems

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JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND control-TRANSACTIONS OF THE ASME 1997年第3期119卷 447-454页

作者： Ephanov, AV Hurmuzlu, Y Mechanical Engineering Department Southern Methodist University Dallas TX 75275

This paper presents an approach to the implementation of sensory feedback in a robotic telemanipulation system. The system considered here consists of kinematically similar master-slave robotic manipulators. We propose a control scheme whereby the slave tracks the motion commanded by the human operator through the master mechanism. The scheme also accommodates, in a unified manner, different sources of sensory feedback. These include combined effects of the interaction with unknown environments and changes in structural properties of the slave manipulator due to additional unknown loads. The control algorithm is based on continuously sliding variable structure control, which is a nonlinear and highly robust control scheme. Due to the robustness of the scheme, the need Sor a priori information about the environment and the load is minimal. This information can be passed on to the system in the form of upper bounds of the interaction forces and additional lends. Experimental studies with a Pneumatic Haptic Interface (PHI) system were conducted to evaluate the performance of the proposed scheme. We used a virtual slave with percent 25 uncertainty to verify the robustness of the controller. We have shown that the proposed scheme can accurately estimate the environmental interaction torques and can robustly track the trajectories commanded by the human operator.

关键词： Robotics Haptics Mechanical properties Stress Robustness control algorithms Uncertainty Robust control Trajectories (Physics) control equipment Feedback Manipulators

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Active parameter control of nonlinear vibrating structures

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JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME 1989年第3期56卷 658-666页

作者： Masri, S. F. Miller, R. K. Dehghanyar, T. J. Caughey, T. K. Univ So Calif Dept Civil Engn Los Angeles CA 90089 USA CALTECH Div Engn & Appl Sci Pasadena CA 91106 USA

A simple, yet efficient method is presented for the on-line vibration control of nonlinear, multidegree-of-freedom systems responding to arbitrary dynamic environments. The procedure uses nonlinear auxiliary mass dampers with adjustable motion-limiting stops located at selected positions throughout a given nonlinear system. A mathematical model of the system to be controlled is not needed for implementing the control algorithm. The degree of the primary structure oscillation near each vibration damper determines the damper's actively-controlled gap size and activation time. By using control energy to adjust the damper parameters instead of directly attenuating the motion of the primary system, a significant improvement is achieved in the total amount of energy expended to accomplish a given level of vibration control. In a related paper, the direct method of Lyapunov is used to establish that the response of the controlled nonlinear primary structure is Lagrange stable. Numerical simulation studies of several example systems, as well as an experimental study with a mechanical model, demonstrate the feasibility, reliability, and robustness of the proposed semi-active control method.

关键词： Oscillations Motion Computer simulation Reliability Vibration dampers Vibration control Dampers Nonlinear systems Robustness control algorithms

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An Economic Model Predictive control Approach for Wind Power Smoothing and Tower Load Mitigation

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JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND control-TRANSACTIONS OF THE ASME 2020年第6期142卷 1-10页

作者： Shaltout, Mohamed L. Alhneaish, Mohamed M. Metwalli, Sayed M. Cairo Univ Mech Design & Prod Engn Dept Fac Engn Giza 12613 Egypt Sabratha Univ Dept Mech Engn Fac Engn Zawiya Libya

Wind power intermittency represents one of the major challenges facing the future growth of grid-connected wind energy projects. The integration of wind turbines and energy storage systems (ESS) provides a viable approach to mitigate the unfavorable impact on grid stability and power quality. In this study, an economic model predictive control (MPC) framework is presented for an integrated wind turbine and flywheel energy storage system (FESS). The control objective is to smooth wind power output and mitigate tower fatigue load. The optimal control problem within the model predictive control framework has been formulated as a convex optimal control problem with linear dynamics and convex constraints that can be solved globally. The performance of the proposed control algorithm is compared to that of a baseline wind turbine controller. The effect of the proposed control actions on the fatigue loads acting on the tower and blades is investigated. The simulation results, with various wind scenarios, showed the ability of the proposed control algorithm to achieve the aforementioned objectives in terms of smoothing output power and mitigating tower fatigue load with negligible effect on the wind energy harvested.

关键词： Blades control algorithms control equipment Dynamics (Mechanics) Energy storage Fatigue Flywheels Integrated systems Optimal control Optimization Predictive control Rotors Simulation results Stress Thrust Wind Wind energy Wind power Wind turbines Wind velocity

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