In this paper we study the output feedback control problem using a decentralized dynamic feedback control scheme. We propose a numerical procedure which consists in the evaluation of the decentralized feedback gains s...
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In this paper we study the output feedback control problem using a decentralized dynamic feedback control scheme. We propose a numerical procedure which consists in the evaluation of the decentralized feedback gains such that the closed-loop behaviour of the decentralized system approaches, in the least squares sense, the evolution of a target centralized closed-loop plant. In this way, the synthesis problem reduces to the identification of a set of unknown parameters in a linear system of ordinary differential equations. Since also the time derivatives of the target states can be computed, the solution can be determined by solving a linear least squares problem, where no difficulty due to local minima and good initial estimate occur.
A thruster assisted position mooring system includes different control functions for station keeping and motions damping of the horizontal-plane motions. A new nonlinear passivity-based state observer producing the th...
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A thruster assisted position mooring system includes different control functions for station keeping and motions damping of the horizontal-plane motions. A new nonlinear passivity-based state observer producing the thruster control actions has been implemented and verified in full-scale tests. Even though sophisticated filtering and control techniques are applied in the high-level controlsystems, unforeseen load peaks caused by process disturbances acting on the local actuation system may challenge the power plant stability, if no proper precaution is taken. Both high and low level control aspects concerning integrated positioning and electrical propulsion system are addressed.
The purpose of this paper is to describe some main aspects on the development of an integrated CAD Toolbox for nD system theory, named nD controlsystem Toolbox, for use with the software product. MATLAB and the assoc...
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The purpose of this paper is to describe some main aspects on the development of an integrated CAD Toolbox for nD system theory, named nD controlsystem Toolbox, for use with the software product. MATLAB and the associated Extended Symbolic Math Toolbox. The developed toolbox consists of several functional packages which provide various basic tools and facilities for both numerical and symbolic manipulations required in analysis and synthesis of 2D controlsystems such as stability test, factor coprime factorizations and solution of various linear matrix equations, etc. that usually involve very complicated procedures.
This paper presents results of research aimed at improving efficiency of coordinated on-line control of system voltage and reactive power on the basis of developing models, methods, and a controlsystem, integrating t...
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This paper presents results of research aimed at improving efficiency of coordinated on-line control of system voltage and reactive power on the basis of developing models, methods, and a controlsystem, integrating traditional numerical techniques with fuzzy logic technology. An approach associated with experimental design is considered to construct diverse types of sensitivity indices, which serve as the basis for multi-attribute evaluating efficiency of control actions and, therefore, for forming rules included in knowledge base. Questions of the construction and tuning of linguistic variables as well as rational implementation of fuzzy logic procedures are discussed.
The purpose of this study is to design a gain-scheduled feedback compensator for a system constrained on the input. Description of the input saturation by the hyperbolic tangential function transfers the system descri...
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The purpose of this study is to design a gain-scheduled feedback compensator for a system constrained on the input. Description of the input saturation by the hyperbolic tangential function transfers the system description to a form of a linear parameter-dependent system. This formulation allows applying the gain-scheduling control synthesis via linear matrix inequalities (LMI). In order to avoid the windup phenomena caused by input limitation suppression of the input derivatives is employed. While the input derivatives could not be taken into account in the previous studies because of using the discontinuous functions as the input limitations, in this study it is available to take account of the input derivatives in the controller design. This means that the designed controller includes integrators and constructs a type-one controlsystem. Consideration of input derivatives may mitigate sudden change of the input even if there is no feedback loop of error between input and output of the nonlinear function. Simulation results show usefulness of the proposed design method.
An active suspension control approach is designed for a quarter-vehicle suspension system using a filtered feedback control scheme and a novel compressible fluid suspension system. Analysis of feedback for the mechani...
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An active suspension control approach is designed for a quarter-vehicle suspension system using a filtered feedback control scheme and a novel compressible fluid suspension system. Analysis of feedback for the mechanical subsystem shows that motions of the sprung mass above and below the wheel frequency can be mitigated using skyhook damping plus active filtering of spring and damping coefficients. The frequency-dependent filtering is accomplished through an outer control loop that generates the target strut force, plus an inner force control loop. Performance of the active suspension control is demonstrated in simulations.
In this paper we present a direct approach for auto-tuning PID controllers. The approach is based on loop-shaping principles. Auto-tuning is accomplished under closed-loop system excitation without fitting a model of ...
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In this paper we present a direct approach for auto-tuning PID controllers. The approach is based on loop-shaping principles. Auto-tuning is accomplished under closed-loop system excitation without fitting a model of the system. The tuning procedure recursively adapts PID parameters to achieve a target loop-shape. In simulation testing the procedure works very well for systems with integrators, dead-time, lead dynamics, inverse response, sensor noise and colored noise disturbances. Here we present an example of a first order plant with delay operating under a colored noise disturbance.
This paper is concerned with the modeling and control of steering system as a subsystem of lateral control architecture of heavy vehicles for the Automated Highway systems. A steering system retrofitted with an actuat...
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This paper is concerned with the modeling and control of steering system as a subsystem of lateral control architecture of heavy vehicles for the Automated Highway systems. A steering system retrofitted with an actuator is considered. The input and output of the steering system are the reference steering angle command to the actuator and the actual steering angle of the front wheel respectively. Open loop experimental data is fitted to a second order linear model. A linear loop-shaping controller has been designed and experimentally verified. It has also been successfully used as an inner-loop controller of the vehicle lateral controlsystem in the open and closed loop experiments of the heavy vehicle system.
Recently, a new version of the TCP mechanism, called TCP Vegas, is proposed, and has potential to achieve better performance than current mechanisms such as TCP Tahoe and Reno. This paper considers a window-based flow...
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Recently, a new version of the TCP mechanism, called TCP Vegas, is proposed, and has potential to achieve better performance than current mechanisms such as TCP Tahoe and Reno. This paper considers a window-based flow control mechanism based on a slightly modified congestion avoidance mechanism of TCP Vegas, and introduces its mathematical model described by a nonlinear difference equation. We calculate its fixed point, and a stability condition of the fixed point is derived.
We analyze the problem of real-time thickness estimation for patterned wafers during an etching process using in situ spectroscopic ellipsometry. For that, a two-stage estimation algorithm is proposed. The first stage...
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We analyze the problem of real-time thickness estimation for patterned wafers during an etching process using in situ spectroscopic ellipsometry. For that, a two-stage estimation algorithm is proposed. The first stage is an automatic model calibration algorithm that uses the data collected during an initial interval. The second stage is a nonlinear state estimation systemdesigned for the tuned model. We study the sensitivity of this estimation strategy to variations in the wafer parameters and the process conditions.
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