An efficient C-0 continuous two-dimensional finite-element model has been presented in this paper for the control of laminated composite and sandwich plates embedded/surface-bonded with piezoelectric layers and subjec...
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An efficient C-0 continuous two-dimensional finite-element model has been presented in this paper for the control of laminated composite and sandwich plates embedded/surface-bonded with piezoelectric layers and subjected to mechanical loading as well as electric potential. The problem of modeling of smart laminates involves the coupling between mechanical and electrical fields. The structural component is modeled by an efficient equivalent single-layer plate theory, which ensures interlaminar shear-stress continuity and zero transverse shear-stress conditions at the top and bottom of the plate surfaces. Moreover, this theory contains unknowns defined at the reference plane (i.e., midplane) only. The electric field is modeled using layerwise theory, which contains the unknowns at each layer interfaces. The proposed combine model, which may be called a refined hybrid plate model, is implemented to analyze the coupled problem of piezoelectricity in laminated composites and sandwich plates.
Large dead time is a significant control problem and source of instability for the control loop. A Smith Predictor scheme provides a conventional large dead time compensation leaving other process dynamics to the sepa...
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Large dead time is a significant control problem and source of instability for the control loop. A Smith Predictor scheme provides a conventional large dead time compensation leaving other process dynamics to the separate controller. The real long dead time processes, such as heat transfer and flow control systems, typically exhibit long time delays intertwined with other process dynamics. One of the authors, Roman Gorecki, proposed and implemented a new algorithm, based on the principle of simplification of the control system transfer function, to deal with this issue. The concept of this new algorithm, called a Simplifying controller, is briefly presented. It is followed by the real system example where a heat transfer process control system with use of the Simplifying controller is described. The Simplifying controller algorithm offers improved control for large dead-time process control applications. (C) 1999 Elsevier Science Ltd. All rights reserved.
This study aims to define a cost-optimal solution based on demand response (DR) actions for a thermal energy storage system with a ground source heat pump in detached residential houses in a cold climate. This study f...
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This study aims to define a cost-optimal solution based on demand response (DR) actions for a thermal energy storage system with a ground source heat pump in detached residential houses in a cold climate. This study finds out the minimum life cycle cost (LCC) of thermal energy storage over the period of 20 years by observing different temperature set points (55-95 degrees C) and sizes (0.3-1.5 m(3)) of a hot water storage tank with developed DR control algorithms. Three different control algorithms were studied: (A) a momentary DR control algorithm based on real-time hourly electricity price (HEP), (B) a backwards-looking DR control algorithm based on previous HEPs and (C) a predictive DR control algorithm based on future HEPs. This research was carried out with the validated dynamic building simulation tool IDA Indoor Climate and Energy. The results show that by using the predictive DR control algorithm the maximum annual savings in total delivered energy and cost are about 12% and 10%, respectively. The minimum LCC can be achieved by the smallest studied storage tank size of 0.3 m(3) with 60 degrees C as the temperature set point, but the effect of storage tank size on LCC is relatively small. (C) 2016 Elsevier Ltd. All rights reserved.
A comparative study was performed on two types of plug-in hybrid electric vehicles (PHEVs): the GM Volt and the Toyota Prius Plug-in Hybrid. First, the powertrain models of the two vehicles were derived. Based on the ...
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A comparative study was performed on two types of plug-in hybrid electric vehicles (PHEVs): the GM Volt and the Toyota Prius Plug-in Hybrid. First, the powertrain models of the two vehicles were derived. Based on the dynamic models, a detailed component control algorithm was developed for each PHEV Specifically, a control algorithm was proposed for motor generator I (MG1) and MG2 to achieve optimal engine operation. Additionally, an energy management strategy for selecting the operation mode was developed from the viewpoint of fuel economy, battery state of charge and vehicle velocity. Using the dynamic model of the control algorithm for each PHEV, simulations were performed, and the simulation results were verified by comparing them with those obtained using the Powertrain System Analysis Toolkit simulator for the plug-in Prius. Based on the simulation results, a comparative study was performed, and it was found that the role and capacity of MG1 and MG2 and the mode selection algorithm must be determined depending on the configuration of the PHEV.
Development of guidance and control algorithms for autonomous solid circular parachutes is addressed. This effort is a part of the Affordable Guided Airdrop System that integrates a low-cost guidance and control syste...
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Development of guidance and control algorithms for autonomous solid circular parachutes is addressed. This effort is a part of the Affordable Guided Airdrop System that integrates a low-cost guidance and control system into fielded cargo air delivery systems. First, the underlying Affordable Guided Airdrop System concept, architecture, and components are described. Then a synthesis of a classical optimal control based on Pontrjagin's maximum principle is suggested. Then the development of a practical control algorithm is detailed. Simulation and flight-test results of the final Affordable Guided Airdrop System demonstration are also presented.
We stated mathematical model of dynamics and control algorithm of tracking-searching head, placed on a ground moving object. Numerical analysis was performed for investigation of head dynamics under effect of kinemati...
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We stated mathematical model of dynamics and control algorithm of tracking-searching head, placed on a ground moving object. Numerical analysis was performed for investigation of head dynamics under effect of kinematic excitations from moving object.
Injection velocity is one of the key parameters in the injection molding process that has significant effect on part quality, influencing common problems, such as flashing and short shots. Different products require s...
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Injection velocity is one of the key parameters in the injection molding process that has significant effect on part quality, influencing common problems, such as flashing and short shots. Different products require specific molding conditions, including mold and melt temperatures, velocity profiles, and polymers, making the injection velocity dynamics vary significantly and difficult for high precision velocity control. Two predictive controllers were developed to control the screw injection velocity. The first approach uses a position sensor as feedback and a simplified predictive controller to track an injection velocity setpoint profile. The controller was developed and implemented utilizing single-step change and multistep change open loop tests. The second strategy uses a multimodel dynamic matrix predictive controller to overcome the nonlinear characteristics of the injection velocity dynamics as the mold is being filled. Velocity feedback is provided by high speed processing of the position analog signal. This approach utilizes several open loop injection velocity profiles to generate corresponding dynamic matrices for the controller. As a result, this controller is modified or retuned automatically when setpoint changes in injection velocity occur, as well as when using different polymers and molds. The close loop results for both simulations and real time control have demonstrated that the two predictive controllers provided good setpoint tracking performance for wide ranging position and velocity profiles.
This article reports on a low Reynolds number experimental study of the unsteady lift characteristics of an NACA 0009 airfoil pitched about its midchord, equipped with a 27% trailing-edge flap that could be independen...
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This article reports on a low Reynolds number experimental study of the unsteady lift characteristics of an NACA 0009 airfoil pitched about its midchord, equipped with a 27% trailing-edge flap that could be independently deflected. The airfoil normal force, obtained from integrated surface pressure measurements, was captured during rapid, trailing-edge flap-only deflections;rapid, arbitrary, pitch-only excursions;and combined rapid pitch and flap-deflection motions, The measured aerodynamic response of the flapped airfoil to the various flap, airfoil, and airfoil-flap combination motions was compared to theoretical and panel-code-computed aerodynamic-response predictions. These comparisons, and the results of now visualization experiments, led to the observation that both the flap's effectiveness and the airfoil's lift-curve slope were higher during their motion than their steady-state values, and essentially matched their inviscid theoretical values.
Among flourishing control studies on air-breathing hypersonic vehicles (AHVs), actuator characteristics have not been fully accommodated. This study gives a comprehensive consideration to physical actuators of AHVs th...
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Among flourishing control studies on air-breathing hypersonic vehicles (AHVs), actuator characteristics have not been fully accommodated. This study gives a comprehensive consideration to physical actuators of AHVs that have transient dynamics and magnitude/rate constraints by introducing an adaptive reference governor and an optimizing allocation module. After implementing a tangent tracking error-based back-stepping design, the derived control algorithm is low-complexity, whose effectiveness is verified by simulations.
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