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Control Applications, 1999. Proceedings of the 1999 IEEE International Conference on

Date 22-27 Aug. 1999

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  • Proceedings of the 1999 IEEE International Conference on Control Applications [front matter]

    Page(s): i - H
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    Freely Available from IEEE
  • 1999 CCA/CACSD General Index of Authors, Speakers, Chairpersons, and Organizers

    Page(s): xxxiv - xlvi
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  • Tracking control of vehicles using nonlinear model

    Page(s): 1667 - 1672 vol. 2
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    Studies automatic operation of vehicles aiming at making the position and the attitude angle of four-wheeled vehicles follow target trajectories. A control theory which enables tracking of various routes is described by using a model which allows variable velocity. In this case the model is expressed as a nonlinear system. Since analytical evaluation of the performance is difficult for a nonlinear system, the control performance is evaluated through numerical simulations. This research focuses on two points: examination of the model with variable velocity, and evaluation of the control theory to follow a target trajectory controlling velocity of a vehicle View full abstract»

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  • Controlling line tension in thruster assisted mooring systems

    Page(s): 1104 - 1109 vol. 2
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    Addresses the potential for energy reduction obtained by using dynamic line tensioning in thruster assisted position mooring systems. Traditionally, mooring systems have been designed in such a way that thruster assistance has not been necessary under normal environmental conditions. However, as oil production moves into deeper waters, such over-dimensioned mooring systems are no longer feasible. Thus, new “hybrid” solutions must be developed, in which increased thruster action compensates for fewer, and lighter, anchor lines. In the paper, controlling the line tensions dynamically is suggested as an additional means of station keeping, and a control law is derived based on passivity. A model consisting of a rigid-body submodel for the vessel, and a finite element submodel for the mooring system is presented and used for simulations. The simulations show the performance of the proposed control system View full abstract»

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  • Control of a continuously stirred tank reactor using an asymmetric solution of the state-dependent Riccati equation

    Page(s): 893 - 898 vol. 2
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    The state-dependent Riccati equation (SDRE) method is used to control the nonlinear nonminimum-phase dynamics of a continuously stirred tank reactor (CSTR). The benefits of using the SDRE method are that it can be directly applied to the nonminimum-phase system and hard bounds can be imposed on the control activity. From simulation analysis, it is determined that a complicated state-dependent state weighting matrix Q(x) would be required in order to produce satisfactory responses to changes in the set point of the reactor. To avoid the problem of finding such a state weighting matrix, an asymmetric solution of the SDRE is used instead of the symmetric positive-definite solution. Since there are an infinite number of asymmetric solutions, the paper discusses the process that was used in obtaining the selected asymmetric solution. Simulations are performed which produce a level of confidence that the closed loop system is asymptotically stable and is robust to parameter variations in the chemical concentration level in the educt flow View full abstract»

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  • Global attitude/position regulation for underwater vehicles

    Page(s): 1768 - 1773 vol. 2
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    A nonlinear controller is designed for a 6 DOF model of an unmanned underwater vehicle (UUV) which includes both the kinematics and the dynamics. It is shown how the use of a Lyapunov function consisting of a quadratic term in the velocity (both linear and angular), a quadratic term in the position and a logarithmic term in the attitude leads to a design of a control law that achieves global asymptotic stabilization to an arbitrary set point in position/attitude. The control law is made linearly bounded by avoiding cancellation of some of the quadratic nonlinearities in the model. No information about the inertia matrix, the damping, and the Coriolis/centripetal parameters is used in the controller, endowing it with a certain amount of parametric robustness. The control law is given in terms of the modified Rodrigues parameters. An extensive simulation study shows that the proposed control law achieves excellent tracking for slowly changing trajectories, even though it is designed only for set point regulation. The nonlinear controller dramatically outperforms a linear controller View full abstract»

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  • Gain-scheduled control of a fossil-fired power plant boiler

    Page(s): 905 - 909 vol. 2
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    The objective is to optimize the control of a coal fired 250 MW power plant boiler. The conventional control system is supplemented with a multivariable optimizing controller operating in parallel with the conventional control system. Due to the strong dependence of the gains and dynamics upon the load, it is beneficial to consider a gain-scheduling control approach. Optimization using complex-μ synthesis results in unstable LTI controllers in some operating points of the boiler. A gain-scheduling approach allowing for unstable fixed LTI controllers is applied. Gain-scheduling which interpolates between unstable controllers is not allowed using traditional schemes. The results show that a considerable optimization of the conventional controlled system is obtainable. Also the gain-scheduled optimizing controller is seen to have a superior performance compared to the fixed LTI optimizing controllers operating alone View full abstract»

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  • High-performance direct-drive flight actuators: advanced technology demonstration

    Page(s): 1229 - 1234 vol. 2
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    A concept in design of fly-by-wire actuator systems is developed to be implemented in advanced flight vehicles. To attain the specified vehicle performance, highly reliable flight actuators are needed to be deployed. To satisfy severe requirements on weight and size, efficiency and torque density, steady-state and dynamic characteristics, ruggedness and reliability, survivability and maintenance, novel flight actuator systems are developed using high-performance stepper motors with advanced power electronics controlled by microprocessors. It is illustrated that the desired performance and integrity are guaranteed. Weight and size are decreased, reliability and survivability are increased, by using the advanced actuator technology reported. Permanent-magnet stepper motors can be directly attached to control surfaces, and redundancy needed is achieved. This solution enhances the reliability by eliminating geartrains and ensures compact, highly integrated assembling compared with the existing actuators. Permanent-magnet stepper motors are needed to be controlled. A new design method is reported to design control laws, and the Lyapunov stability theory is used to prove the robust stability and tracking as well as to find the feedback coefficients. It is illustrated that innovative control algorithms are designed based upon the electric machinery features to maximize the electromagnetic torque developed. Experiments have been performed to illustrate the effectiveness and feasibility of direct-drive actuator technology View full abstract»

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  • Multivariable adaptive model output following control system based on backstepping strategy and its application to parallel inverted pendulums

    Page(s): 1241 - 1248 vol. 2
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    In this paper, we propose a design method of an output feedback-based adaptive model output following control system based on backstepping strategy for MIMO plants. It is shown that the proposed adaptive control system has robustness with regard to output-dependent disturbances. Further, the proposed adaptive control method is applied to the parallel inverted pendulums with output-dependent disturbances and the effectiveness of the control system is confirmed through experiments View full abstract»

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  • An experimental investigation of active and passive control of rotating stall in axial compressors

    Page(s): 985 - 990 vol. 2
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    Presents results to date from on-going analytical and experimental investigations of passive and active control methods for suppression of stall in axial flow compressors, The passive control method involved inclusion of flow separators in the inlet and outlet ducts of the compressor. The active control methods investigated included bleed valve modulations, flow recirculation from plenum bleed to inlet of the compressor and fuel flow modulations. It was found that in contrast to theoretical expectations, the use of separators in the inlet and/or outlet ducts did not prevent the onset of rotating stall. However, it was found that with proper number of separators, the onset manner of the rotating stall was tempered. Experimental results to date indicate that it is possible to significantly suppress the onset of rotating stall through a combination of passive and active control schemes, and thus, extend the useful operational range of a compressor View full abstract»

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  • Transient stability enhancement of power systems by robust adaptive control with saturation constraint

    Page(s): 1187 - 1192 vol. 2
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    Proposes a backstepping technique for designing a discrete-time adaptive excitation controller to enhance the transient stability of power systems under large sudden faults. This approach can be applied directly to a nonlinear model of the power system and it allows for abrupt changes in the power system parameters caused by three phase short circuit faults. It is shown that the proposed excitation controller can enhance transient stability when the power system suffers large sudden faults. The robustness of the power system under the proposed excitation controller is established in the presence of time-varying parametric uncertainties, unmodeled dynamics and external disturbances. Both theoretical analysis and simulation results are presented to show the effectiveness of the proposed controller View full abstract»

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  • The open protocol standard for computerized building systems: BACnet

    Page(s): 1585 - 1590 vol. 2
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    BACnet spent nine years under development by a committee drawn from manufacturers, universities, government agencies and consulting firms in an effort to produce a truly open protocol whereby equipment from different manufacturers can interoperate in a complete, integrated building automation control system. The result is a standard that defines all the elements of communication between devices, from the abstract language of objects and services right down to the physical LANs. With its adoption as an ANSI standard and the interest shown world-wide, it is safe to say that BACnet points the way to the future of communication within building automation controls View full abstract»

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  • Stability issues for vehicle platooning in automated highway systems

    Page(s): 1377 - 1382 vol. 2
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    This paper discusses notions and definitions pertinent to the stability of systems operating in platoon structures. This paper reviews some of the existing stability definitions (string stability), and discusses how the available platoon information and separation policies influences the stability results. It turns out that some of these notions and control policies do not suffice to ensure safety (collision avoidance) of the platoon. This is illustrated via simulation examples showing that there exists, in general, a non-empty set of initial condition that results in a colliding situation. This set is not necessarily small. In connection with this, we propose a new way to formulate the platooning problem aiming at solving some of these difficulties View full abstract»

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  • Robust attitude controller design of linear parameter varying spacecraft via μ synthesis and gain scheduling

    Page(s): 979 - 984 vol. 2
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    Studies the three-axis attitude control problem of a spacecraft which has slowly rotating flexible solar paddles. By the paddle rotation, the structure of dynamical coupling of the paddle vibration with the spacecraft attitude dynamics drastically changes. In order to control such a class of spacecraft, we derive a parameter-varying modal equation and a generalized plant of descriptor form. Then, two stabilizing controllers, i.e., a fixed μ controller and a gain scheduled H controller are designed. Based on some numerical studies for the ETS-VI spacecraft model, their capabilities are shown and compared with each other View full abstract»

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  • Model reference adaptive control with multi-rate type neural network for electro-pneumatic servo system

    Page(s): 1716 - 1721 vol. 2
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    In this paper, we propose a design scheme which combines a model reference adaptive control with a neural network (NN) for the electropneumatic servo system. In this design scheme, we adopt a multirate type NN in which an update-time of weights is selected as multiple of a sampling-time. The effectiveness of the proposed design scheme is confirmed by experiments using the existent electropneumatic servo system View full abstract»

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  • Binary excitation based system identification for precision ballscrew table

    Page(s): 1394 - 1399 vol. 2
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    Mechanical devices usually come with undesirable nonlinearities such as friction, backlashes and saturation. Under the assumption of linear systems, the commonly seen identification schemes utilize sinusoidal excitation signals for parameter identifications. However, the data for identification are unavoidably distorted by the fore-mentioned nonlinearities and the identification result is not satisfactory. In this paper, a method based on binary excitation signals is proposed. The method does not suffer from the problem of nonlinear distortions in signal shape and is able to determine the bias term for asymmetric frictions such that an accurate model can be derived. An 0.01 μm high precision ballscrew table with asymmetric frictions is utilized as a test plant for this approach. To result obtained proves to be very successful View full abstract»

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  • Bilinear disturbance-accommodating optimal control of semi-active suspension for automobiles

    Page(s): 1496 - 1501 vol. 2
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    The design of suspension is very important for ride-comfort on automobiles. A lot of active and semi-active suspensions have been studied. In recent years, the car with active or semi-active suspension has been put into practice. Since the active suspension needs large power and space, a semi-active suspension have received attention. In this study, the bilinear disturbance accommodating control theory is established and it is applied to the semi-active control of suspension for automobiles. In this study, a 1/2 body model with 4-DOF is used. By applying the proposed bilinear disturbance accommodating optimal control to the semi-active suspension, its performance is investigated in the simulation. As a result, it showed better performance than the passive control with respect to the vertical acceleration and the pitch angular acceleration of the car body which influence ride-comfort for automobiles View full abstract»

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  • Swing up of an inverted pendulum by simulator-based foresight control

    Page(s): 1255 - 1259 vol. 2
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    One of the typical nonlinear system is a pendulum. Cause of difficulties of controlling a pendulum is mismatching of number between inputs and outputs, that is to say, single input and double outputs. The feature of a pendulum is nonlinear as to angle and linear as to cart position. Another point is that state equations do not have terms of position of a cart. In addition, the angle of a pendulum must satisfy the dynamic equation at horizontal line. In order to swing up a pendulum of these properties, first, we define a reference angle of a pendulum which satisfies the dynamic equation at horizontal line. After the pendulum goes up around upright position, we change the curve of reference angle so that the pendulum standstill at the origin. In other word, when the pendulum system becomes a linear time-invariant system, we define the ideal curves of both angle and position which will converge to the origin. The angle of the pendulum is controlled by SFC (simulator-based foresight control) all the way which can be applicable for a nonaffine nonlinear system View full abstract»

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  • Detecting controller malfunctions in electromagnetic environments. I. Modeling and estimation of nominal system function

    Page(s): 1525 - 1530 vol. 2
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    A strategy for detecting control law calculation errors in critical flight control computers during laboratory validation testing is presented. This paper addresses part I of the detection strategy which involves the use of modeling of the aircraft control laws and the design of Kalman filters to predict the correct control commands View full abstract»

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  • Characterization of a recoverable flight control computer system

    Page(s): 1519 - 1524 vol. 2
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    The design and development of a closed-loop system to study and evaluate the performance of the Honeywell Recoverable Computer System (RCS) in electromagnetic environments (EME) is presented. The development of a Windows-based software package to handle the time-critical communication of data and commands between the RCS and flight simulation code in real-time, while meeting the stringent hard deadlines is also submitted. The performance results of the RCS and characteristics of its upset recovery scheme while exercising flight control laws under ideal conditions as well as in the presence of electromagnetic fields are also discussed View full abstract»

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  • Stop and go controller for adaptive cruise control

    Page(s): 1692 - 1697 vol. 2
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    In the field of vehicle control, conventional cruise control systems have been available on the market for many years. During the last years, modern cars include more and more electronic systems. These systems are often governed by a computer or a network of computers programmed with powerful software. One of those new services is adaptive cruise control (ACC) (or autonomous intelligent cruise control, AICC), which extends the conventional cruise control system to include automated car following when the preceding car is driving at a lower speed than the desired set-speed. The focus of ACC has mainly been directed towards high-speed highway application, but to improve the comfort to the driver also low-speed situations must be considered. The paper presents an ACC system that is capable of car following in low-speed situations, e.g. in suburban areas, as well as in high-speed situations. The system is implemented in a test car and the result is evaluated View full abstract»

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  • Model based predictive control in RTP semiconductor manufacturing

    Page(s): 1636 - 1641 vol. 2
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    Temperature control in single-wafer semiconductor reactors has become a hot topic. The interest in the subject illustrates the fact that the temperature measurement and control issues are far from trivial. This is due to the reactor design which is inherently non-isothermal, to the principal difficulties in measuring wafer temperature (or film thickness) in real-time and to the typically large interaction present between zones in radiantly heated systems. CVD-RTP (chemical vapor deposition-rapid thermal processing) reactors offer a challenge to control engineers in that the control of temperature uniformity over the wafer surface is of utmost importance for the next generation of processing equipment. This paper presents a solution based on the methodology of model based predictive control View full abstract»

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  • Adaptive estimation and accommodation of loss of control effectiveness using a Lyapunov method

    Page(s): 1538 - 1542 vol. 2
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    A Lyapunov approach is used to design regulators for systems subject to loss of control effectiveness. Control effectiveness factors are used to quantify faults entering control systems through actuators. An adaptive Kalman filtering algorithm is used to estimate the state as well as the amount of reduction of control effectiveness in a closed-loop setting. The state estimate is fed back to achieve the steady state regulation, while the control effectiveness estimate is used for the online tuning of the control law. The resulting regulator is guaranteed to be stable when the estimation error is sufficiently small. An aircraft longitudinal model is used to demonstrate the use of the Lyapunov method View full abstract»

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  • Sensor fusion technique for cable following by autonomous underwater vehicles

    Page(s): 1779 - 1784 vol. 2
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    A sensor fusion technique is proposed for autonomous underwater vehicles (AUVs) to track underwater cables. The work presented is an extension of the vision based cable tracking system proposed by that authors (1997, 1998) and Balasutiya (1998). The focus of this paper is to solve the two practical problems encountered in vision based systems; namely: 1) navigation of AUV when cable is invisible in the image, and 2) selection of the correct cable (interested feature) when there are many similar features appearing in the image. The proposed sensor fusion scheme uses deadreckoning position uncertainty with a 2D position model of the cable to predict the region of interest in the image. This reduces the processing data increasing processing speed and avoids tracking other similar features appearing in the image. The proposed method uses a 2D position model of the cable for AUV navigation when the cable features are invisible in the predicted region. An experiment is conducted to test the performance of the proposed system using the AUV “Twin-Burger 2”. The experimental results presented in this paper show how the proposed method handles the above mentioned practical problems View full abstract»

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  • Time optimal control for the pendulum-cart system in real-time

    Page(s): 1249 - 1254 vol. 2
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    An experiment in practical implementation of simulated time-optimal control in a laboratory cart-pendulum system is described. The simulation results are compared with two types of measured trajectories of the real system: generated by an implementation of the time-optimal control, and generated by a rule-based algorithm. The technologies of rapid prototyping, real-time simulation and hardware-in-the-loop simulation are used for direct synthesis of control algorithms. The feasibility of construction of time-optimal controller in the real system has been pointed out View full abstract»

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