A new direct closed-loop identification method only using the plant input/output data acquired through an output inter-sampling scheme is presented in this paper. By taking the faster sampling of the system output tha...
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A new direct closed-loop identification method only using the plant input/output data acquired through an output inter-sampling scheme is presented in this paper. By taking the faster sampling of the system output than the control interval, we can clarify that the inter-sampled plant model can also be described by a SIMO model structure, which can provide the identifiability of the closed-loop. One of the advantages is that the proposed identification method using the inter-sampled output observations can remove the ordinary restrictive identifiability condition, and it is not required that the reference input holds the persistently exciting (PE) property. Its effectiveness is demonstrated through an experimental study using a magnetic suspension system.
In the field of vehicle control, conventional cruise controlsystems have been available on the market for many years. During the last years, modern cars include more and more electronic systems. These systems are oft...
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In the field of vehicle control, conventional cruise controlsystems 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 controlsystem 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. This 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.
In office buildings, the requirement is that the room air-conditioning controlsystem has to provide a comfortable thermal feeling for the working people. While energy saving may sometime conflict with comfort, it is ...
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In office buildings, the requirement is that the room air-conditioning controlsystem has to provide a comfortable thermal feeling for the working people. While energy saving may sometime conflict with comfort, it is possible to eliminate the wasteful use of energy associated its overuse without prejudice to comfort. The basic concept is that the target set values for the room temperature should be changed dynamically so as to suit the constantly changing room environment. This paper shows that the well-known comfort index PMV is useful to airconditioning controlsystems aimed at both energy-saving and comfort.
This paper aims at proposing a new integrated design method of structure-control combined system: such as several types of mechanical systems equipped with vibration controlsystem in order to suppress the structural ...
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This paper aims at proposing a new integrated design method of structure-control combined system: such as several types of mechanical systems equipped with vibration controlsystem in order to suppress the structural vibration. When the proposed method is applied to the design of a structure-control combined system, the closed loop pole placement of the reduced order model of the combined system is specified in advance as a design requirement. The proposed method is constructed from two steps: in the first step, output feedback controlsystem is designed for the initial closed loop system in order to realize the specified closed loop pole placement;and next step, structural and vibration controlsystemdesign parameters are simultaneously optimized to minimize the objective function subject to constraints on the pole placement. Scalar objective function is defined as a linear combination of several measures of the optimality of the structure design and the vibration controlsystemdesign. According to the proposed method, the closed loop pole placement of the reduced order model is preserved through the iterative optimum design process. The effect of the proposed method is shown by the numerical example. Not only structural design parameters but also vibration controlsystemdesign parameters are successfully optimized under the objective function minimization.
We examine the use of in-cylinder measurements for engine control, with emphasis on emissions control during cold start. First, the cold start emissions control problem is described. An overview of previous research i...
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We examine the use of in-cylinder measurements for engine control, with emphasis on emissions control during cold start. First, the cold start emissions control problem is described. An overview of previous research in the area of in-cylinder measurements for control is presented, including sensors for pressure and other quantities. Next, analysis of cylinder pressure is described. Lastly, a cold-start engine test stand, and preliminary experimental tests of cylinder pressure measurement and realtime processing are presented.
Loop-shaping H∞ controller is designed for a nonlinear multivariable boiler-turbine system. Simulations show that the designed controller has good tracking, disturbance rejection properties, and robustness against th...
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Loop-shaping H∞ controller is designed for a nonlinear multivariable boiler-turbine system. Simulations show that the designed controller has good tracking, disturbance rejection properties, and robustness against the variations of the operation points due to the plant nonlinearity. In order to implement the complex H∞ controller, we propose a method to reduce it to a multivariable PID controller. The final simplified controller is composed of three main channel PI controllers plus one off-channel PI controller. It reveals the underlying structure of the designed controller and that of the overall boiler-turbine controlsystem. Simulation results show that it maintains the good properties of the original controller.
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...
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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 MBPC (Model Based Predictive control).
This paper considers position and attitude control of large space structures composed of a number of subsystems which are interconnected by springs and dampers. A decentralized control law of dynamic displacement feed...
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This paper considers position and attitude control of large space structures composed of a number of subsystems which are interconnected by springs and dampers. A decentralized control law of dynamic displacement feedback compatible with subsystems is applied under the assumption that sensors and actuators are collocated. The overall closed-loop system is robustly stable against perturbations in mass, damping, and stiffness if rigid modes of each subsystem are controllable and observable. The objective of this paper is to derive conditions under which stability of the overall system is preserved even when some local controllers fail. The conditions are expressed in terms of the stiffness (or damping) matrices and interconnection location matrices of the subsystems whose local controllers fail.
This paper compares three different uncertainty estimation techniques in terms of predicting a priori performance bounds on the closed-loop system. A major benefit of computing the performance bounds is they expedite ...
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This paper compares three different uncertainty estimation techniques in terms of predicting a priori performance bounds on the closed-loop system. A major benefit of computing the performance bounds is they expedite the controller implementation process, which is a critical component in the acceptance of the controlsystem by the process operators. A key ingredient in computing these bounds is uncertainty estimation. The three methods evaluated are the Coprime Factor Uncertainty Method, Zhu's Asymptotic Method, and Bayard's Frequency-Domain Method. We compare the performance bounds obtained by applying these uncertainty estimation procedures on a paper machine control case study.
So as to achieve high density and high speed access of magnetic disk drives, integrated optimization method is applied for designing the head-suspension assemblies. Approximation is used to the model of a head-suspens...
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So as to achieve high density and high speed access of magnetic disk drives, integrated optimization method is applied for designing the head-suspension assemblies. Approximation is used to the model of a head-suspension assembly, which makes it possible to enjoy a nice analytical result on Ricatti equations. Using this trick, we can obtain an explicit expression of the optimal controller in state space form. Based on this setup, the simultaneous optimization problem both on active and passive parameters is reduced to a simpler one. A numerical example is given to show that a better performance of a magnetic disk drive can be obtained by the simple design procedure.
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