佐藤 孝雄

This paper proposes a new method for designing a variable structure controller in the presence of load disturbance or plant parameter variation. In conventional methods, servo tracking is achieved by a variable structure controller designed using integral compensation. However, the proposed method employs proportional compensation as well as integral compensation, and optimal proportional and integral gain for stabilizing a closed-loop system can be obtained by solving the Riccati equation. As a result, robust servo tracking can be achieved and further, transient response is better than that of conventional methods. The proposed method is applied to an inverted pendulum system, and its effectiveness is demonstrated by both simulation and experiment.

Most weigh feeders are controlled by a PID control method, and it is desirable to achieve high performance with this PID control. The present paper discusses the application of a generalized predictive control (GPC)-based PID controller to a weigh feeder. In conventional methods, GPC-based PID controllers are designed using a step-type reference signal, but in control of a weigh feeder, a reference input to be followed by a measured signal is a ramp-type signal because the measured signal is discharged mass. Hence, control of a weigh feeder using a GPC-based PID controller is enhanced for tracking a ramp-type signal. Because GPC can be expressed by PID parameters, the proposed method can be easily adopted in various industries. Experimental results show that a weigh feeder is well controlled using the enhanced GPC-based PID controller. (C) 2009 Elsevier Ltd. All rights reserved.

This study discusses a design method for a multirate control system, where the sampling interval of the plant output is an integer multiple of the hold interval of the control input. A closed-loop system is assumed to be stabilized by a state feedback control law with an observer, and the feedback control law is extended to improve the intersample response. One of the advantages of the proposed method is that the control law is redesigned independently of the closed-loop system. Hence, the intersample response can be improved independently of the sampled response. Numerical simulations are presented to demonstrate the effectiveness of the proposed method.

This study describes the development of a car orientation measurement system using a single camera. We have proposed the method that calculate a car's 3D distance and direction from 4 corner points of its license plate image. However, to obtain a car orientation by this method, we have to detect and track the license plate shape with high accuracy. Therefore, in this report, we considered to track the license plate outline using particle filter. The effectiveness of our approach has been verified through experiments using real car images. © 2010 SICE.

This study reports that a weigh feeder is controlled using a performance-adaptive control method in which controller parameters are recalculated only when parameter estimation deteriorates. In this method, a PI control law is based on generalized minimum variance control (GMVC). Hence, a design parameter in GMVC is adjusted such that given control specifications are satisfied, and then, PI parameters are based on a redesigned GMVC law. The objective of this study is to reduce the variance of the variation in the control input. To this end, a conventional performance-adaptive control method is modified, and its effectiveness is shown by applying to a weigh feeder. © 2010 SICE.

In design of a weigh feeder control system, most controllers employed in industry are designed using proportional and integral (PI) compensations, and it is desirable to achieve high performance by PI control. Hence, a generalized minimum variance control (GMVC)-based PI control system is designed for a weigh feeder, and the design parameters of GMVC are adjusted on the basis of control performance. Because the GMVC-based PI control is based on control performance, the proposed method can be easily adopted in industry. An experimental result demonstrates the effectiveness of the proposed design method.

This paper discusses a design method for a sample-date system, in which a continuous-time plant is controlled using a discrete-time controller. It is assumed that the sampling interval of plant output is an integer multiple of the hold interval of control input, that is, the control system is a multirate system. Using the state-space representation, a multirate control law, which stabilizes a closed-loop system, is extended independently of the sample response. In the proposed method, a multirate control is redesigned such that the steady-state intersample response is improved. Hence, the intersample response can be improved independently of the sample response.

This paper proposes a new method for designing a weigh feeder control system. The model of a weigh feeder cannot be obtained accurately because its dynamic characteristics are time varying and its high frequency vibration modes are not easily identified. In this paper, a weigh feeder is assumed to be a first-order plus integrator system, and a control law consists of a constant feed-forward control input and a feedback loop to obtain a simple control method. The objective of this study is to design a control law to be actually employed in industry. To this end, a control law is designed using proportional gain for control error and steady-state control input. However, the proportional gain must be finely tuned. Hence, it is tuned using a discrete-time extremum-seeking method. In the proposed method, the proportional gain is tuned using an iterative feedback tuning. Therefore, the proposed method has the advantage that the control performance is not deteriorated due to gain fluctuation because the proportional gain is not changed in an experiment. As a result, the proposed control law has a simple structure and its control parameters can be intuitively understood. Consequently, the proposed design method can be easily adopted in industry. Numerical and experimental results demonstrate its effectiveness.

This paper proposes a new controller for track-seeking control of a head in a Hard Disk Drive (HDD). The sampling period of the head position is restricted, but the hold period of a control input can be changed to improve HDD system, performance. Hence this paper proposes a method for designing Generalized Predictive Control (GPC) in a multirate system., where the sampling period is longer than the hold period. In design of a standard GPC, intersample behavior is not evaluated because the controller is based on the optimization of the sample behavior. However, the intersample behavior has to be evaluated in the HDD system. Therefore, the proposed controller's derivation is based on an objective function that includes intersample behavior as well as sample behavior. The proposed method is applied to a benchmark problem and its effectiveness is demonstrated.

This paper proposes a new method for designing a multirate control system, in which a sampling interval of plant output is (in integer multiple of a hold interval of a control input. To employ the effect of integral compensation in the multirate system, two-degree-of-freedom (2DOF) Generalized Predictive Control (GPC) is proposed only when there is a modeling error or disturbance. In this paper, a one-degree-of-freedom (1DOF) multirate GPC without integral compensation is first derived, and next the 1DOF multirate GPC is extended into 2DOF control using integral compensation. Numerical examples demonstrate the effectiveness of the proposed method.

This paper proposes a new control method for a weigh feeder. A weigh feeder has been widely employed in industry because it can dispense powder at a specified rate or amount. The proposed controller is mainly divided into a feed-forward and a feedback compensators. In order to obtain a simple controller, the former gives a steady-state control input designed using a nominal plant gain, and the latter consists of proportional gain and the control error between a reference input and a plant output. Because the proportional gain must be designed to stabilize a closed-loop system, it is updated using an extremum-seeking method. As a result, the control performance of the proposed method can be improved by seeking its extremum value. The effectiveness of the proposed method is demonstrated by both simulation and experimental results.

This paper proposes a new method for designing a multirate output feedback control system, where the update interval of the control input is an integer multiple of the sampling interval of the plant output. The proposed method is designed by extending a conventional multirate output feedback control using the latest information of a plant. Hence, the proposed method can improve the control performance compared with conventional methods without the latest information. Furthermore, the obtained control structure can be simpler than conventional methods. An inverted pendulum system is controlled to demonstrate the effectiveness of the proposed method.

This paper proposes a new method for designing a self-tuning PID controller. A PID controller is designed on the basis of generalised predictive control with a terminal matching condition (γGPC) to automatically tune its PID parameters. The proposed PID controller has a time-varying proportional gain to precisely achieve γGPC performance. Furthermore, a PID controller is designed on the basis of γGPC extended by using coprime factorisation to obtain stable proportional gain. Hence, γGPC can be well approximated by the proposed PID controller. A numerical example demonstrates its effectiveness. © 2009 Inderscience Enterprises Ltd.

The present paper discusses the design methods for Generalized Minimum Variance Control (GMVC)-based PID controllers in a two-degree-of-freedom (2DOF) system. The PID parameters of the PID controllers are designed art the basis of GMVC, and they are designed as self-tuning controllers. In the present paper, PID parameters are decided such that a GMVC law is approximated by a PID controller. Therefore, in design of a 2DOF PID controller based on GMVC with a feed-forward compensator (abbreviated as FF-type GMVC), because the order of the feed-forward compensator depends on a dead-time, the approximation deteriorates if the dead-time is long. In the present paper, GMVC with a pre-compensator (PC-type GMVC) is approximated by a 2DOF PID controller to obtain better approximation. Furthermore, a 2DOF PID controller having time-varying proportional gain is based on a strongly stable GMVC with a pre-compensator to improve control performance. Numerical examples are given to confirm the effectiveness of the proposed method.

This study proposes an adaptive control method of a weigh feeder. A weigh feeder dispenses material into a process at a precise rate, and it has been employed in industries, e.g., process control, cement manufactur ing plants, food industry equipment, and so on. To introduce advanced control into industries, self-tuning controllers are designed for controlling a weigh feeder. Three difference controllers are designed; one degree-of-freedom (1DOF) PID, 1DOF PD, and two degree-of-freedom (2DOF) PD controllers, and these control methods are compared through experimental results. Because discharged mass is measured by employing loss-in-weight method, a reference input followed by a plant output is ramp-type, and a type-2 control system has to be designed. Since the controlled object includes an integrator, a type-2 control system can be obtained by using 1DOF PID controller. In design of 2DOF PD control, a pre-compensator is designed to eliminate steady-state velocity error. Further, to be compared with 1DOF PID and 2DOF PD control, a 1DOF PD controller is designed.In this paper, PID and PD controllers are designed on the basis of generalized minimum variance control (GMVC) to obtain useful control methods adopted in industries. In design of the proposed control methods, GMVC can be replaced precisely with a simple PID or PD controller, and advanced control performance can be obtained. Experimental results are shown and compared, and the effectiveness of the proposed design method is shown. Copyright © 2007 International Federation of Automatic Control All Rights Reserved.

The present paper proposes a new design method for a dual-rate system, in which a plant in continuous time is controlled by updating a control input in discrete time, in which the sampling interval of the plant output differs from the update interval of the control input. A dual-rate control law that stabilizes a discrete-time closed-loop system is extended. One of the advantages of such an extension is that the dual-rate control law can be redesigned to be independent of the discrete-time closed-loop system. Consequently, the intersample response can be improved by making it independent of the sampled response using the newly introduced design parameters. The present paper proposes a design method for design parameters to improve the intersample response in the steady state. Numerical examples are presented to confirm the effectiveness of the proposed method.

This paper discusses design of Generalized Predictive Control (GPC) scheme. GPC is designed in two cases; the first is a dual-rate (DR) system, where the sampling interval of a plant output is an integer multiple of the holding interval of a control input, and the second is a fast-rate single-rate (FR-SR) system, where both the holding and sampling intervals are equal to the holding interval of the DR system. Furthermore, the relation between them is investigated, and this study gives the conditions that FR-SR and DR GPC become equivalent. To this end, a future reference trajectory of DR GPC is rewritten, and a future predictive output of the FR-SR GPC is rearranged.

This paper proposes a design method of the Generalized Predictive Control (GPC) strategy which can take account of intersample behavior as well as sampled behavior. To this end, a discrete-time equivalent plant model and cost function for a continuous-time plant incorporated with zero-order hold and discrete-time controller are derived, and the modified discrete-time GPC is designed. To verify the effectiveness of our proposed method, the controller is applied to a benchmark problem of a hard-disk drive. (c) 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

This paper proposes a new design method of a pressure control system in a furnace of a thermal power plant boiler. To improve the control performance of the pressure control system in a furnace controlled by using self-tuning I-P controllers, a feed-forward compensator is introduced. Simulation results are illustrated to show the effectiveness of our proposed method.

A pendulum rod of a nonlinear system is controlled by using sliding model control. To control the angle of the pendulum rod, a new design method of the sliding model control is proposed using proportional and integral compensation. Conventional and our proposed control methods are applied into the nonlinear system, those control methods are compared through simulation and experiment. © 2007 IEEE.

This paper proposes a new design method of a GPC-Based PID controller. The proportional gain of a PID controller is time-varying, and the PID controller is designed using the future reference input. Hence, a GPC law can be approximated by the PID controller finely. Because a controller of GPC has to be stable to obtain stable proportional gain, using extended GPC using coprime factorization, the PID controller is designed.

This paper proposes a design method of Generalized Minimum Variance Control (GMVC) in sampled-data systems, where a continuous-time plant is controlled with a discrete-time controller. The proposed design method derives a discrete-time control law which minimizes a continuous-time performance function with a zero order hold. Because the proposed method evaluates not only sampling instants but. intersample, the intersample performance of the proposed method is improved better than conventional design methods in discrete-time. Finally, we illustrate numerical simulation results in order to show the effectiveness of the proposed method.

In this paper, a weigh feeder is controlled by using a self-tuning controller. To make a plant output follow a ramp-type reference input without a steady-state error, we propose a new design method for generalized minimum variance control with a pre-compensator. In order to confirm the effectiveness of the proposed method, experimental results are shown.

An effective design method of a proportional-integral-derivative (PID) controller is proposed. The PID parameters of the PID controller are designed on the basis of a generalized predictive control (GPC) law. The PID controller has a time-varying proportional gain, and the PID parameters are designed using the future reference trajectory of the GPC. Finally, numerical examples are shown for illustrating the effectiveness of the proposed method. (C) 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Generalized minimum variance control is designed in a multi-rate system where the sampling interval of a plant output is longer than the holding interval of a control input. Because new design parameters are introduced, intersample ripples in the multi-rate system are suppressed by weighting the variation in the control input. Furthermore, the proposed method is an extension of a conventional design method. Finally, simulation results are illustrated in order to show the effectiveness of the proposed method. (c) 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

In this paper a new design method of a self-tuning PID controller is proposed. The PID controller is designed based on generalized predictive control (GPC) including a future reference trajectory. The PID controller given in this paper is based on GPC and, is I-PD type controller. It is shown that the design parameter adjusting the future reference trajectory changes only the integral time of the PID controller. In order to illustrate the effectiveness of the proposed method, numerical examples are shown.

The behavior of a pendulum rod of a mechanical system in chaotic state is controlled. The system is nonlinear with unknown parameters, and an adaptive backstepping method is applied to control the pendulum rod. A validation experiment shows that the behavior of the pendulum rod can be made to follow a reference behavior.

in this paper a new design method of a self-tuning I-PD controller is proposed. The I-PD controller is designed based on a generalized predictive control (GPC) law. By using a conventional design method of the I-PD controller based on the GPC law, it is impossible to introduce future reference trajectory into the I-PD controller. The future reference trajectory of the GPC approaches a setpoint value gradually from a present output, that is one of the features of the GPC. The proposed method can introduce the advantage of the GPC into the IPD controller exactly because the proposed method expresses the future reference trajectory suitably when the set-point value is given as a step type signal. This paper shows that the structure of a PID controller based on the GPC law becomes an I-PD type by using the proposed method and that a design parameter of the GPC which adjusts the future reference trajectory inuences only an integral time of the I-PD controller. in order to illustrate the effiectiveness of the newly proposed method, numerical examples are shown. Copyright © 2005 IFAC.

This paper proposes a new design method of a PID controller.We design the PID controller based on generalized minimum variance control (GMVC) with a steady state predictive output (GMVCS). The proposed method has better approximation than conventional design schemes since the orders of compensators of a GMVCS law do not increase even if a dead-time increases. Furthermore, in this paper it is shown that GMVCS has an advantage that it is possible to place poles of the closed-loop system at desired places. Hence, the PID controller is designed based on the pole-placement GMVCS. Finally, we illustrate numerical simulation results in order to show the effectiveness of the proposed control algorithm. Copyright © 2005 IFAC.

This paper proposes a new design method of a pressure control system in a furnace of a thermal power plant boiler. Because the plant is a non-linear system with interactions among variables, it is difficult to utilize linear control theory. Additionally the actual plant is controlled by proportional and integral compensations [6, 7]. Hence, in a conventional method, the plant has been approximated by two independent first-order plus dead-time models and then two controllers have been designed for each of the first-order plus dead-time models [6, 7]. And self-tuning I-P controllers based on GPC laws have been also used in order to approximate the plant by time-invariant linear models. Since the conventional method regards the interactions as disturbances, it is required to suppress the influence of the interactions. Therefore, in this paper, to reduce the influence of interactions among variables, a feed-forward compensator is introduced to the conventional method newly. The proposed method is especially useful when a dead-time of the plant is long. Simulation results are given to show the effectiveness of the proposed method.

Generalization minimum variance control (GMVC) has been designed in a single-rate system. In this paper, a design method of GMVC in an input multiple multirate system is proposed. Finally, to illustrate the effectiveness of the proposed method, numerical examples are shown. © 2005 SICE.

A pressure control system in a furnace of a thermal power plant boiler is controlled by using two I-P controllers and a feed-forward compensator. The two I-P controllers are designed based on generalized predictive control laws. To improve control performance, a new design method of the feed-forward compensator is proposed. A simulation result is given to show the effectiveness of the proposed method © 2005 SICE.

Control Experiments of an Inverted Pendulum System. A pendulum rod of an inverted pendulum system is controlled by a backstepping method and linear control theory using linearization. Finally, both simulation and experimental results are shown. © 2005 SICE.

This paper proposes a new track-seeking control method of a hard disk drive (HDD). The use of generalized predictive control considering intersample behavior moderates vibration of a head in the HDD due to mechanical resonance modes which emerge at high frequencies. Finally, we illustrate numerical examples to show the effectiveness of the proposed method. © 2005 SICE.

An Fe-Pd ferromagnetic shape memory alloy micro actuator is controlled. The actuator is displaced by raising temperature of the actuator by Jule heating because of shape memory characteristic. Controlling supplied voltage by PID control, displacement of the actuator is made to follow reference values. Finally, experimental results are shown. © 2005 SICE.

一般化予測制御(Generalized Predictive Control; GPC)とサンプル点間の出力値と目標値の誤差を評価関数に組み入れたGPCの両制御手法を磁気ディスク装置のヘッド位置決め制御に適用する．シミュレーション結果より通常のGPCに比べサンプル点間を考慮したGPCは目標値追従特性が優れていることを示す．

入力多重型Multirate装置は制御性能が向上する一方で制御入力がしばしば振動的になりやすい．この影響はサンプル点間のリップルに現れ，時として大きな偏差を生む．本研究ではサンプル点間を考慮した一般化予測制御則をMultirate系へ拡張し，サンプル点間のリップルを改善する．

This paper proposes a new design scheme for a self-tuning PID controller. To improve the transient property for a reference signal and the robustness to disturbance, the proposed controller is designed in the form of two-degree-of-freedom. Expressions to calculate PID parameters from the identified plant coefficients are given. These expressions are derived by approximating the PID controller to an extended generalized minimum variance control (GMVC) law, which can adjust both of reference response and disturbance response independently. Using a numerical example, the control performance of the proposed method is compared with those of PID controllers designed by other schemes.

This paper proposes a new generalized minimum variance controller (GMVC) using state-space approach. The controller consists of a state feedback and a reduced-order observer with poles at z = 0. A coprime factorization of the state-space based controller is also obtained. It is shown that the GMVC designed by state-space approach is equivalent to the GMVC given by solving Diophantine equations and polynomial approach. The equivalence is proved by comparing coprime factorizations of the two controllers. From the results of this paper, it may be possible to apply advanced design schemes given by state-space control theory to the design of GMVC.

This paper proposes a new generalized minimum-variance controller (GMVC) having new design parameters by using the coprime factorization approach for a multi-input multi-output (MIMO) case. The method is directly extended from a conventional GMVC and used to construct the controller it needs to solve only one Diophantine equation as in the conventional method. In this paper, by using double-coprime factorization, a simple formula for the closed-loop system given by the parametrized controller is obtained and using the formula, it is proved that the closed-loop characteristic from the reference signal to plant output is independent of the selection of the design parameters and the poles of the controller can be chosen by the design parameters without changing the closed-loop system. © 2000 American Automatic Control Council.

This paper proposes a new design scheme for a self-tuning PID controller. Expressions to calculate PID parameters from the identified plant coefficients are given. These expressions are derived by approximating the PID controller to the generalized minimum variance control (GMVC) law. To obtain a better approximation, the PID controller has a time-varying proportional gain. The PID control law approximates the strongly stable GMVC resulting in a stable closed-loop system and a stable control law. Using a numerical example, the control performance of the proposed method is compared with those of PID controllers designed by other schemes. Copyright (C) 2000 IFAC.

In this paper, the generalized predictive control (GPC) with a terminal matching condition for single-input single-output (SISO) plants proposed by Kwok and Shah [6] is extended so that it can be applied to multi-input multi-output (MIMO) plants. For the extension to MIMO case, a state-space approach is used in the proposed method while a polynomial approach is used in the conventional method. This is because a state-space approach for the design of the proposed GPC makes the extension to MIMO case possible. In addition, a steady-state predictor originally derived in this paper using a state-space approach is shown to be completely equivalent to that in the conventional method when SISO plant is designed. Finally, a numerical example is demonstrated to show that a terminal matching condition in the MIMO case has the same role for improving performances of the controlled system as in the SISO case using conventional method.