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Control Systems Technology, IEEE Transactions on

Issue 1 • Date Jan. 2012

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  • Table of contents

    Publication Year: 2012 , Page(s): C1 - C4
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  • IEEE Transactions on Control Systems Technology publication information

    Publication Year: 2012 , Page(s): C2
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  • Robust Control of Solid Oxide Fuel Cell Ultracapacitor Hybrid System

    Publication Year: 2012 , Page(s): 1 - 10
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (705 KB) |  | HTML iconHTML  

    Mitigating fuel starvation and improving load-following capability of solid oxide fuel cells (SOFC) are conflicting control objectives. In this paper, we address this issue using a hybrid SOFC ultracapacitor configuration. Fuel starvation is prevented by regulating the fuel cell current using a steady-state invariant relationship involving fuel utilization, fuel flow, and current. Two comprehensive control strategies are developed. The first is a Lyapunov-based nonlinear control and the second is a standard H robust control. Both strategies additionally control the state of charge of the ultracapacitor that provides transient power compensation. A hardware-in-the-loop test stand is developed where the proposed control strategies are verified. View full abstract»

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  • Nonlinear Controller Designs for Thermal Management in PCR Amplification

    Publication Year: 2012 , Page(s): 11 - 30
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1053 KB) |  | HTML iconHTML  

    We have developed a theoretical model for a cascade two-stage Peltier device based on the electrothermal dynamics of Peltier modules and the heat balance equations of the interfacing materials. Both open- and closed-loop data are used to tune the scaling factors of the nonlinear model. The effectiveness of the model is validated over a large temperature range with the experimental data from a thermal cycling application of the Peltier device used to perform the polymerase chain reaction (PCR), a genetic amplification technique having important medical diagnostic applications. Based on the theoretical model, two novel nonlinear controllers are designed for a PCR cycling temperature profile. The first controller is an extension of conventional input-to-state feedback linearization design to a class of nonlinear systems that is not only affine on the control but also affine on the square of control inputs. The desired performance is achieved by tuning the parameters to control the convergent rates of the tracking errors. The second one is a switching controller design, which switches between a nonlinear pseudo-proportional-integral-differential (PID)/state feedback controller and a linear time-invariant proportional-integral (PI)/state feedback controller. A Lyapunov function method is used to develop the algorithm for the nonlinear controller, whose parameter values at the switching time are used in the linear controller. Such a combination of linear and nonlinear controllers could reduce the calculation burden and minimize the steady-state errors. Both controllers are tested with our simulation model and implemented in a microcontroller. We verified the designs with improved temperature tracking performances compared to our earlier linear switching design on reduced overshoots (<; 0.5 °C) and settling time (8-10 s faster). The modeling methodology and the feedback linearization-based controller design are scalable and both nonlinear designs can avoid futu- - re local model identifications when applied to different references, therefore, are easily extended to other thermal applications. View full abstract»

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  • Observer-Based Intensity-Feedback Control for Laser Beam Pointing and Tracking

    Publication Year: 2012 , Page(s): 31 - 47
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1909 KB) |  | HTML iconHTML  

    This paper presents an investigation of the control problem of aiming a laser beam under dynamic disturbances, using light intensity for feedback only. The idea is to steer the beam with a biaxial microelectromechanical mirror, which is driven by a control signal generated by processing the beam intensity sensed by a single photodiode. Since the pointing location of the beam is assumed to be unavailable for real-time control, a static nonlinear mapping from the 2-D beam location to the photodiode sensor measurement output is estimated with the use of the least-squares algorithm, treating data from a biaxial optical position sensor as inputs to the static mapping. This formulation results in a nonlinear Wiener-Hammerstein system composed of a linear subsystem connected in series to a nonlinear static output mapping. Conceptually, the controller design problem is addressed with the integration of an observer and a pair of linear time-invariant single-input/single-output controllers into one system. This approach motivates two research questions that are considered independently in this paper. The first is about the multiple-experiment observability of the considered nonlinear optical system. The second is about the search of an heuristic method, based on the extended Kalman filter (EKF) algorithm, for estimating the state of the linear subsystem, necessary for implementing the proposed control approach. Here, we present a compelling answer for the first question and we propose a methodology to tackle the second. It is important to state that the problem considered in this article is very challenging, because the nonlinear static output map of the system is not one-to-one. In order to address this issue, we introduce the idea of integrating stable output disturbance models into the design of the proposed EKF-based observer. This is the main contribution of the paper, which could have an impact in the way other nonlinear control problems are addressed in the future. Evi- - dence of the suitability of the proposed method is provided through experimental results from a case relevant to free-space optics for communications and directed energy applications. View full abstract»

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  • Robust Adaptive Boundary Control of a Vibrating String Under Unknown Time-Varying Disturbance

    Publication Year: 2012 , Page(s): 48 - 58
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1013 KB) |  | HTML iconHTML  

    In this paper, robust adaptive boundary control is developed for a class of flexible string-type systems under unknown time-varying disturbance. The dynamics of the string system is represented by a nonhomogeneous hyperbolic partial differential equation (PDE) and two ordinary differential equations. Boundary control is proposed at the right boundary of the string based on the original distributed parameter system model (PDE) to suppress the vibration excited by the external unknown disturbance. Adaptive control is designed to compensate the system parametric uncertainty. With the proposed robust adaptive boundary control, all the signals in the closed-loop system are guaranteed to be uniformly ultimately bounded. The state of the string system is proven to converge to a small neighborhood of zero by appropriately choosing design parameters. Simulations are provided to illustrate the effectiveness of the proposed control. View full abstract»

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  • Fast Linear Model Predictive Control Via Custom Integrated Circuit Architecture

    Publication Year: 2012 , Page(s): 59 - 71
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1279 KB) |  | HTML iconHTML  

    This paper addresses the implementation of linear model predictive control (MPC) at millisecond range, or faster, sampling rates. This is achieved by designing a custom integrated circuit architecture that is specifically targeted to the MPC problem. As opposed to the more usual approach using a generic serial architecture processor, the design here is implemented using a field-programmable gate array and employs parallelism, pipelining, and specialized numerical formats. The performance of this approach is profiled via the control of a 14th-order resonant structure with 12 sample prediction horizon at 200-μs sampling rate. The results indicate that no more than 30 μs are required to compute the control action. A feasibility study indicates that the design can also be implemented in 130 nm CMOS technology, with a core area of 2.5 mm2. These results illustrate the feasibility of MPC for reasonably complex systems, using relatively cheap, small, and low-power computing hardware. View full abstract»

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  • Design and Robustness Analysis of Discrete Observers for Diesel Engine In-Cylinder Oxygen Mass Fraction Cycle-by-Cycle Estimation

    Publication Year: 2012 , Page(s): 72 - 83
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1369 KB) |  | HTML iconHTML  

    This paper presents three discrete observer designs for cycle-by-cycle estimation of the in-cylinder oxygen mass fraction at the intake valve closing (IVC) on diesel engines equipped with exhaust gas recirculation systems. These observers can provide critical in-cylinder condition oxygen fraction information that is useful for control of combustion, in particular advanced combustion modes on a cycle-by-cycle basis. The observers were designed based on Lyapunov analysis and linear matrix inequality techniques. By input-to-state stability analysis, robust properties of the three observers were revealed. Simulations using a high fidelity, computational, GT-Power engine model exhibited that the observers can effectively estimate the in-cylinder oxygen mass fraction at IVC on a cycle-by-cycle basis at both steady-state and transient operations. In addition, comparisons were made to evaluate the observers' robustness against measurement and parametric uncertainties/inaccuracies, such as volumetric efficiency uncertainty, exhaust pressure sensor uncertainty, and temperature sensor dynamics. Experimental results from a medium-duty diesel engine were provided to show the effectiveness of the observers and to validate the in-cylinder oxygen fraction estimation in an indirect and innovative way by utilizing the measured cylinder pressure signals. View full abstract»

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  • Model Predictive Idle Speed Control: Design, Analysis, and Experimental Evaluation

    Publication Year: 2012 , Page(s): 84 - 97
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1617 KB) |  | HTML iconHTML  

    Idle speed control is a landmark application of feedback control in automotive vehicles that continues to be of significant interest to automotive industry practitioners, since improved idle performance and robustness translate into better fuel economy, emissions and drivability. In this paper, we develop a model predictive control (MPC) strategy for regulating the engine speed to the idle speed set-point by actuating the electronic throttle and the spark timing. The MPC controller coordinates the two actuators according to a specified cost function, while explicitly taking into account constraints on the control and requirements on the acceptable engine speed range, e.g., to avoid engine stalls. Following a process proposed here for the implementation of MPC in automotive applications, an MPC controller is obtained with excellent performance and robustness as demonstrated in actual vehicle tests. In particular, the MPC controller performs better than an existing baseline controller in the vehicle, is robust to changes in operating conditions, and to different types of disturbances. It is also shown that the MPC computational complexity is well within the capability of production electronic control unit and that the improved performance achieved by the MPC controller can translate into fuel economy improvements. View full abstract»

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  • Design and Control of Hardware-in-the-Loop Simulations for Testing Non-Return-Valve Vibrations in Air Systems

    Publication Year: 2012 , Page(s): 98 - 110
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2221 KB) |  | HTML iconHTML  

    Non-return-valves are commonly used across the range of industries for prevention of reverse flow conditions where they often exhibit premature failure due to self-sustained oscillations that are a result of fluid structure interactions. This paper details the design of a proof of concept hardware-in-the-loop (HWIL) simulator and its controller for simulating fluid-structure interactions of a non-return-valve with an arbitrary air system geometry. A numerical model of an airbitrary air system is coupled to the physical non-return-valve via a purpose built fast acting control valve and associated instrumentation to simulate both stable and unstable vibrations. The vibrations of the non-return-valve in the HWIL simulator are compared against its vibrations in the real air system and are found to have an excellent agreement for a range of massflows and air system volumes. The simulator described in this paper can be used for simulating other types of passive flow control devices with arbitrary air systems thereby offering potential for significantly reducing the cost of full system tests. View full abstract»

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  • Path Following Control of Planar Snake Robots Using a Cascaded Approach

    Publication Year: 2012 , Page(s): 111 - 126
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1450 KB) |  | HTML iconHTML  

    This paper considers path following control of snake robots along straight paths. Under the assumption that the forward velocity of the snake robot is nonzero and positive, we prove that the proposed path following controller K-exponentially stabilizes a snake robot to any desired straight path. The performance of the path following controller is investigated through simulations and through experiments with a physical snake robot, where the controller successfully steers the snake robot toward and along the desired straight path. View full abstract»

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  • High-Frequency Linear Compressor and Lateral Position Regulation

    Publication Year: 2012 , Page(s): 127 - 138
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1494 KB) |  | HTML iconHTML  

    The mathematical model for the magnetically levitated linear compressor (MLLC), which consists of a magnetic linear actuator (MLA), a pair of active magnetic bearings (AMBs), and a drive rod, is developed. To prevent any potential wear or collision by the drive rod against conventional bearings and certainly reduce noise, the AMB pair is employed to regulate the lateral position deviation of the drive rod. The integral sliding-mode control (ISMC) is synthesized to account for state-dependent system parameters and input nonlinearities for the MLLC system. In addition, the closed-loop stability, under the presence of the reaction force by gas in chamber, is proven by Lyapunov direct method. Finally, the efficacy of the ISMC is verified by intensive computer simulations to ensure its superior regulation capability for lateral position deviation on the drive rod, retention of constant stroke of the piston, and counterbalance against the reaction force by gas during Otto cycle. View full abstract»

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  • On the State-Space Realization of LPV Input-Output Models: Practical Approaches

    Publication Year: 2012 , Page(s): 139 - 153
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (769 KB) |  | HTML iconHTML  

    A common problem in the context of linear parameter-varying (LPV) systems is how input-output (IO) models can be efficiently realized in terms of state-space (SS) representations. The problem originates from the fact that in the LPV literature discrete-time identification and modeling of LPV systems is often accomplished via IO model structures. However, to utilize these LPV-IO models for control synthesis, commonly it is required to transform them into an equivalent SS form. In general, such a transformation is complicated due to the phenomenon of dynamic dependence (dependence of the resulting representation on time-shifted versions of the scheduling signal). This conversion problem is revisited and practically applicable approaches are suggested which result in discrete-time SS representations that have only static dependence (dependence on the instantaneous value of the scheduling signal). To circumvent complexity, a criterion is also established to decide when an linear-time invariant (LTI)-type of realization approach can be used without introducing significant approximation error. To reduce the order of the resulting SS realization, an LPV Ho-Kalman-type of model reduction approach is introduced, which, besides its simplicity, is capable of reducing even non-stable plants. The proposed approaches are illustrated by application oriented examples. View full abstract»

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  • Robust Nonlinear Controls of Model-Scale Helicopters Under Lateral and Vertical Wind Gusts

    Publication Year: 2012 , Page(s): 154 - 163
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (803 KB) |  | HTML iconHTML  

    A helicopter maneuvers naturally in an environment where the execution of the task can easily be affected by atmospheric turbulence, which leads to variations of its model parameters. This paper discusses the nature of the disturbances acting on the helicopter and proposes an approach to counter the effects. The disturbance consists of vertical and lateral wind gusts. A 7-degrees-of-freedom (DOF) nonlinear Lagrangian model with unknown disturbances is used. The model presents quite interesting control challenges due to nonlinearities, aerodynamic forces, under actuation, and its non-minimum phase dynamics. Two approaches of robust control are compared via simulations with a Tiny CP3 helicopter model: an approximate feedback linearization and an active disturbance rejection control using the approximate feedback linearization procedure. Several simulations show that adding an observer can compensate the effect of disturbances. The proposed controller has been tested in a real-time application to control the yaw angular displacement of a Tiny CP3 mini-helicopter mounted on an experiment platform. View full abstract»

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  • Model Predictive Control for a Full Bridge DC/DC Converter

    Publication Year: 2012 , Page(s): 164 - 172
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1186 KB) |  | HTML iconHTML  

    This paper investigates the implementation of both linear model predictive control (LMPC) and nonlinear model predictive control (NMPC) to a full bridge dc/dc converter under starting, overload, and load step change conditions. The control objective is to regulate the output voltage without violating the peak current constraint. The integrated perturbation analysis and sequential quadratic programming method is employed to solve the nonlinearly constrained optimal control problems with 300 μ s sampling time. The experimental results reveal that both the LMPC and NMPC schemes can successfully achieve voltage regulation and peak current protection. The experimental results are reported and several observations, seemingly counterintuitive, are analyzed to offer insight into the use of MPC for these challenging applications. View full abstract»

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  • Fixed-Order H_{\infty } Tension Control in the Unwinding Section of a Web Handling System Using a Pendulum Dancer

    Publication Year: 2012 , Page(s): 173 - 180
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB) |  | HTML iconHTML  

    Flexible materials such as textiles, papers, polymers, and metals are transported on rollers during their processing. Maintaining web tension in the entire processing line under changing web speed is a key factor in achieving good final product quality. Many industrial applications use dancer position feedback to indirectly regulate tension. Although widely used in the industry, pendulum dancers (rotational motion of the dancer roller) have received very little attention in the literature compared to linear ones (translational motion). The lack of clearly identified controllers synthesis methods can thus be noticed, as industry typically uses hand-tuned decentralized PI controllers. An improved alternative based on H methods is proposed in this paper to provide a systematic framework. The focus in this study is the unwind section of a processing line that contains a pendulum dancer (PD). The nonlinear and linear phenomenological models of the unwind section containing the PD are discussed first. The position controller based on dancer position feedback is synthesized using the standard H approach with mixed sensitivity. Because of the high order of the controllers synthesized with this approach, techniques to generate reduced-order controllers are used to calculate a fixed-order controller resembling standard industrial practice. The performance of the proposed controllers is demonstrated by carrying out experiments on a large experimental web handling platform containing four driven rollers, many idle rollers, and a PD in the unwind section. To the best of our knowledge, these are the first published results of successful application of an H controller to a real plant containing a PD. View full abstract»

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  • Nonlinear Identification of a Minimal Neuromuscular Blockade Model in Anesthesia

    Publication Year: 2012 , Page(s): 181 - 188
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (354 KB) |  | HTML iconHTML  

    This brief presents new modeling and identification strategies to address many difficulties in the identification of anesthesia dynamics. The most commonly used models for the effect of muscle relaxants during general anesthesia comprise a high number (greater than eight) of pharmacokinetic and pharmacodynamic parameters. The main issue concerning the neuromuscular blockade system identification is that, in the clinical practice, the input signals (drug dose profiles to be administered to the patients) vary too little to provide a sufficient excitation of the system. The limited amount of measurement data also indicates a need for new identification strategies. A new single-input single-output Wiener model with two parameters is hence proposed to model the effect of atracurium. An extended Kalman filter approach is used to perform the online identification of the system parameters. This approach outperforms many conventional identification strategies, and shows good results regarding parameter identification and measured signal tracking, when evaluated on a large patient database. The new method proved to be adequate for the description of the system, even with the poor input signal excitation and the few measured data samples present in this application. It turns out that the method is of general validity for the identification of drug dynamics in the human body. View full abstract»

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  • A Stochastic Reachability Approach to Portfolio Construction in Finance Industry

    Publication Year: 2012 , Page(s): 189 - 195
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (542 KB) |  | HTML iconHTML  

    The approach to portfolio construction proposed in this paper is based on recent results on stochastic reachability. It is assumed that investors' preferences are expressed in terms of target sets to be reached at each time period over a specified finite horizon. A portfolio is defined optimal if it maximizes the probability of its value to belong to the target sets. A case study drawn from the US market shows the interest and applicability of the approach. The optimal solution we obtain exhibits a contrarian attitude, whereby risky exposures are enhanced in case of negative performances and reduced in case of positive performances. A comparison with the constant proportion portfolio insurance method highlights advantages and drawbacks of the proposed approach. View full abstract»

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  • A Model-Free ON–OFF Iterative Adaptive Controller Based on Stochastic Approximation

    Publication Year: 2012 , Page(s): 196 - 204
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (556 KB) |  | HTML iconHTML  

    A model-free on-off iterative adaptive controller is described for application to microscale servo systems performing repeated motions under extremely strict power constraints. The approach is motivated by the needs of piezoelectric actuators in autonomous microrobots, where power consumption in analog circuitry and/or for position sensing may be much larger than that of the actuators themselves. The control algorithm adjusts switching instances between “on” and “off” inputs to the actuator to minimize an objective function using simultaneously perturbed stochastic approximation of the gradient with just a single sensor measurement in each iteration. Convergence conditions for the gradient approximation are shown to apply when the possibility for a range of possible switching times minimizing the objective function is accounted for, while a method is proposed for avoiding local minima for plants with bounded nonlinearities. The algorithm is tested on a prototype piezoelectric microactuator. View full abstract»

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  • Design of a Fixed-Order Controller for the Track-Following Control of Optical Disc Drives

    Publication Year: 2012 , Page(s): 205 - 213
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (703 KB) |  | HTML iconHTML  

    In this paper, a systematic method for designing a fixed-order controller for the track-following control of optical disc drives is proposed. The design specifications are given in the frequency domain and are expressed as frequency-domain inequalities. On the basis of the generalized Kalman-Yakubovich-Popov lemma, each frequency-domain inequality is converted into linear matrix inequalities of the controller parameters. The controller parameters can be computed efficiently by solving a convex optimization problem to maximize the loop gain around the rotational frequency while satisfying other frequency-domain specifications on the performance and stability. Experimental results show that a reasonable performance can be obtained by using a second-order controller, and the performance can be further improved by using a third-order controller. View full abstract»

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  • NPID and Adaptive Approximation Control of Motion Systems With Friction

    Publication Year: 2012 , Page(s): 214 - 222
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (457 KB) |  | HTML iconHTML  

    This paper proposes a scheme for precise position control of a mechatronic servo system based on linear synchronous motors. The control is based on gain-scheduled proportional integral derivatives (PIDs) (known as NPID in related literature) and adaptive approximation of uncertainties. NPID and adaptive approximation are combined in a constructive way to inherit advantages and overcome limitations of the single methods. In particular, NPID is used to stabilize the nominal plant, and its gains are scheduled so as to minimize the effects of friction and other uncertainties. Adaptive approximation is used to compensate further effects of nonlinearities and obtain a better overall tracking accuracy. A report on an extensive experimental investigation is provided to illustrate the practical advantages of the proposed scheme. View full abstract»

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  • Damping Control in Power Systems Under Constrained Communication Bandwidth: A Predictor Corrector Strategy

    Publication Year: 2012 , Page(s): 223 - 231
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1247 KB) |  | HTML iconHTML  

    Damping electromechanical oscillations in power systems using feedback signals from remote sensors is likely to be affected by occasional low bandwidth availability due to increasing use of shared communication in future. In this paper, a predictor corrector (PC) strategy is applied to deal with situations of low-feedback data rate (bandwidth), where conventional feedback (CF) would suffer. Knowledge of nominal system dynamics is used to approximate (predict) the actual system behavior during intervals when data from remote sensors are not available. Recent samples of the states from a reduced observer at the remote location are used to periodically reset (correct) the nominal dynamics. The closed-loop performance deteriorates as the actual operating condition drifts away from the nominal dynamics. Nonetheless, significantly better performance compared to CF is obtained under low-bandwidth situations. The analytical criterion for closed-loop stability of the overall system is validated through a simulation study. It is demonstrated that even for reasonably low data rates the closed-loop stability is usually ensured for a typical power system application confirming the effectiveness of this approach. The deterioration in performance is also quantified in terms of the difference between the nominal and off-nominal dynamics. View full abstract»

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  • Real-Time Power Management of Integrated Power Systems in All Electric Ships Leveraging Multi Time Scale Property

    Publication Year: 2012 , Page(s): 232 - 240
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (600 KB) |  | HTML iconHTML  

    All-electric ships (AES), enabled by integrated power systems (IPS), have been pursued for both commercial and military applications to meet the increasing ship-board power demand and environmental sustainability initiatives. They necessitate real-time power management (PM) for dynamic reconfiguration to support system critical operations in the event of dynamic load change or IPS component failures. The nonlinear, large scale trajectory optimization problem associated with IPS, along with the non-analytical nature of IPS model, makes many existing methods inadequate in meeting the real-time requirements. In this paper, we develop a methodology that exploits time scale separation, a characteristic associated with IPS dynamics, to achieve real-time optimization. In parallel, a dynamic model of the IPS with gas turbine and fuel cell as power plants is developed that captures the relevant dynamics but is simple enough for real-time optimization. The tradeoffs between the computational efficiency and optimization accuracy are analyzed. The optimization results for IPS PM on a real-time simulator are reported, which illustrate the real-time feasibility of the proposed optimization strategy. View full abstract»

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  • A Motion Planning-Based Adaptive Control Method for an Underactuated Crane System

    Publication Year: 2012 , Page(s): 241 - 248
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (477 KB) |  | HTML iconHTML  

    This brief proposes a motion planning-based adaptive control strategy for an underactuated overhead crane system. To improve the transportation efficiency and enhance the safety of the crane system, the trolley is required to reach the desired position fast enough, while the swing of the payload needs to be within an acceptable domain. To achieve these objectives, a novel two-step design strategy consisting of a motion planning stage and an adaptive tracking control design stage, is proposed to control such an underactuated system as an overhead crane. Specifically, a novel desired trajectory, which satisfies physical constraints of an overhead crane, is proposed for the trolley by fusing theoretical analysis results with the conventional empirical trajectory planning methods. An adaptive control law is then constructed in the second step to make the trolley track the planned trajectory, where some online update mechanism is introduced to ensure that the controller works well with different working conditions. As shown by Lyapunov techniques, the proposed adaptive controller guarantees asymptotic tracking result even in the presence of uncertainties including system parameters and various disturbance. Some experiment results demonstrate that the proposed control method achieves superior performance for the underactuated cranes. View full abstract»

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  • Reactive Path Planning for 3-D Autonomous Vehicles

    Publication Year: 2012 , Page(s): 249 - 256
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB) |  | HTML iconHTML  

    This brief deals with the problem of path planning for 3-D vehicles. The problem is simplified by resolving the workspace into horizontal and vertical planes. The flight path angle and the heading angle are linear functions of the visibility line angles in the vertical and horizontal planes, respectively. Other terms for the deviation and heading regulation are added to the navigation law. The navigation law has two navigation proportionality factors and two deviation parameters corresponding to the horizontal and vertical planes. The method has the ability to generate non-straight paths to the goal. Obstacles and dangerous zones are avoided by correcting the path by changing the values of the parameters. The dynamic constraints are transformed to a restriction in the navigation parameters' space. Our results are illustrated using simulation. View full abstract»

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