All issues
Volume 30, Issue 7
Displaying 1-19 of 19 articles from this issue
- |<
- <
- 1
- >
- >|
-
Saechout VICHAI, Michio NAKANO1994 Volume 30 Issue 7 Pages 742-750
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe control signal in position control systems is inherently constrained by some limited value, such as the current or voltage driving a servo motor is limited by a maximum current or maximum voltage. To design the controller for achieving the desired performances, a fast tracking of set point change and a robustness with respect to the parameter variation, of system, it is necessary to ensure that the control signal satisfies the constraint value. A well-known time optimal Bang-Bang controller yields a shortest time response of a nominal system, however, the response is sensitive to the parameter variation. The other one, high gain control can make the system be robust and track the set point quickly beneath the unconstraint of control signal. Because the existing of contraint of control signal, its performance will be poor such as the overshoot response.
In this paper, we introduce a state feedback control law associated with time scale. The feedback law based on this time scale can, assign the system to be the high gain mode if the time scale is sufficiently large. However, the large time scale causes the control signal over the limited value. This work proposes a control method which attempt to adjust the time scale suitably, in such a way that the control signal being the inner produce of state variable and feedback control law must satisfy the constraint condition at all time. Roughly mention, when the error is quite small, the time scale will be adjusted to the very large value and the system will be high gain nearly.
The study case of a position control system using proposed scheme is simulated by digital computer. The results show the fast tracking response of the control system and the robustness with respect to the parameter change. Finally, the comparison of proposed scheme and the Bang-Bang control, LQR control are shown also.View full abstractDownload PDF (2100K) -
Tetsumi HARAKAWA, Hak-Kyung SUNG, Tadao KAWAGUCHI1994 Volume 30 Issue 7 Pages 751-759
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, we propose a new multirate digital control system where the contrinuous plant with long dead time is stabilized by the layered digital controller which has different sampling periods, respectively. The sampling period of the controller is determined by the dead-time of the output.
In the actual plant, since the identification is not exact, the learning control method is used to improve the performance.
Also, to improve the efficiency of the learning control, the digital controller in the lower layer is tuned by the feed-forward of the control input of the upper layer.
The proposed control method is applied to the Organic Rankin Cycle System in the iron manufacturing process.View full abstractDownload PDF (1811K) -
Shinji SHINNAKA, Norio SAKAKIBARA, Hideki FUKAZAWA1994 Volume 30 Issue 7 Pages 760-766
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSVector control technique rapidly increases the number and spreads the fields of applications of induction motors. For designing and realizing excellent vector controllers for induction motors, it is necessary to analyze and understand the motors deeply. This paper presents vector analysis for vector control of induction motors in much more unified manner than conventional.
First of all, mathematical model of the motors is shown, which is described on vector basis rotating with arbitrary angular velocity. By using this model, instant-time relationships between input power, motor inner power and mechanical output power are analyzed in general manner and their clear physical meanings are given. Next, it is generally analyzed from view points of energy transfer that constant control of magnitude of secondary (or primary) flux is quite proper. This propriety is also analyzed from view point of torque control in vector control method by simple but general way. Finally, relationships between primary, secondary currents and secondary flux are analyzed in both general and flux controlled cases.View full abstractDownload PDF (1182K) -
Takashi KIMURA, Morio TAKAHAMA, Ei TOKUDA, Masahiro OHNO1994 Volume 30 Issue 7 Pages 767-775
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSAuthers have already proposed a new design method to design a robust flight control system for single-input single-output system which is low-sensitive and robust stable.
This method can simultaneously realize pole-zero assignment by Exact Model Matching method, and disturbance zeroing by solving Output Estimation (OE) problem which is one of H∞ Control problems.
In this paper, we expand this method to design a control augmentation system (CAS) for the lateral· directional flight control system (multi-input multi-output system) of a typical small aircraft.
Our new design method can simultaneously satisfy the following 4 design requirments:
(1) Desired closed loop transfer function between reference and controlled variable,
(2) Low sensitivity characteristics,
(3) Low complementary sensitivity characteristics,
(4) Robust stability.View full abstractDownload PDF (1751K) -
Toshiaki HIRATA, Ryoichi TAKAHASHI1994 Volume 30 Issue 7 Pages 776-782
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSRecently, railroad vehicle active suspension have been developed in order to reduce low frequency vibrations caused by the resonance of suspensions equipped between a car body and a truck, and to improve passengers' ride comfort. We consider the above purpose as loop shaping problem in control design, and apply H∞ control theory to solve this problem. Main point is to introduce the weight function which has the maximum gain near the resonance frequency. The proposed H∞ control is robust against the purterbation of the plant model, and has superior performance than LQG control in high frequencies. Also we discuss about the performances of the proposed H∞ control with running test by the experimental vehicle.View full abstractDownload PDF (1607K) -
Koichi YOSHIDA, Tetsuro YABUTA1994 Volume 30 Issue 7 Pages 783-792
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDisturbance compensation control is one of the useful methods for dynamic control of robot manipulators, in which the disturbance observer estimates interference torques such as friction and modelling error as the disturbance. This disturbance torque can be compensated to match the system dynamics with the model. The disturbance consists of external disturbances and that caused by perturbation such as system parameter change and unknown dynamics in the manipulator. The former can be suppressed by using the conventional disturbance compensation control, however, because the latter forms an inner feedback loop, its effects to the system stability and control performance should be considered. In addition, when a dynamic control method is used with the disturbance compensation control, interference between those two controls should also be taken into account.
In this paper, we consider the disturbance compensation control in joint-space. Especially the filter employed in the feedback loop of the estimated disturbance torque is designed by using μ-synthesis to make the system robust stable. Further, from the viewpoint of μ-analysis, we discuss the total system stability and control performance when the dynamic hybrid control method is used with the disturbance compensation control. We show that the combination of these two control methods can achieve high performance hybrid control even though the exact information about the manipulator dynamics is not obtained. Some numerical simulation results are provided to confirm the theoretical development.View full abstractDownload PDF (2620K) -
Kazuhiro KOSUGE, Jun ISHIKAWA, Katsuhisa FURUTA, Kazuo HARIKI, Masaru ...1994 Volume 30 Issue 7 Pages 793-801
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA master-slave manipulator system, in general, consists of a master arm manipulated by a human and a slave arm used for real tasks. Some tasks, such as manipulation of a heavy object, etc., require two or more slave arms operated simultaneously. A Single-Master Multi-Slave Manipulator System consists of a master arm with six degrees of freedom and two or more slave arms, each of which has six or more degrees of freedom. In this system, a master arm controls the task-oriented variables using Virtual Internal Model4) (VIM) based on the concept of“Task-Oriented Control”1)3). VIM is a reference model driven by sensory information and used to describe the desired relation between the motion of a master arm and task-oriented variables. The motion of slave arms are controlled based on the task oriented variables generated by VIM and tailors the system to meet specific tasks. A single-master multi-slave manipulator system, having two slave arms, is experimentally developed and illustrates the concept.View full abstractDownload PDF (2099K) -
Shigeyasu KAWAJI, Nobutomo MATSUNAGA1994 Volume 30 Issue 7 Pages 802-810
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSRecently, to accomplish the contact control of the robot arm, many force control systems have been proposed, for example hybrid control and impedance control. In the literatures, it is not clarified how we can decide the control parameters for given environment, and the stability of force control system is not ensured sufficiently, because in the conventional approaches the control systems were designed for the robot arm and the environment separately. To overcome these problems, we should construct the force control system with consideration of the dynamics of the environment. Furthermore, it is necessary to operate the robot arm smoothly from free space to constraint space.
In this paper, we propose a design method of force control system with consideration of the approach to the environment. The proposed method does not require the change of controllers in the transition from free space to constraint space. Firstly, the force control system using the model following servo controller is constructed and it is shown that the force in constraint space can be controlled and the robot arm move with constant velocity in free space. To reduce the impulsive force at collision, the approaching velocity must be controlled aggressively. So secondly, we introduce the concept of the virtual environment model. Using this model, the approaching velocity can be controlled by setting the virtual environment parameters, and the vibration of force can be reduced. Finally, experimental results demonstrate the effectiveness of the proposed controller.View full abstractDownload PDF (2450K) -
Kyoji TANAKA, Yoshiaki SHIRAI1994 Volume 30 Issue 7 Pages 811-818
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes a method which tracks a specified moving object among mutiple objects with variable velocity, accompanied with “foveation”, independently of camera velocity.
For subjects of recognizing a moving object in sequential images, and for a subject of foveation with rotation control, real time processability is required as well as performance of extracting object. Moreover under the condition of rotating camera, the back-ground imagery is looked as it moves. Therefore it is difficult to separate target from it. Authors have already proposed a method of extracting a specified motion component using each-dimension-separatable spatiotemporal filter applied to an analytic signal, and proposed a method of tracking an object using α-β-γ filter. In the methods, quick rotation of the camera is not assumed, so degradation of extraction performance and delay of motion estimation convergence are probable. Then in the present method, supposing that camera velocity is observable, camera motion is made to be static by the way that coordinate of image is transformed according to the velocity, and the spatiotemporal filter is created in order that a relationship between its pass band and motion velocity is linear. By these methods, independently of camera control velocity, tracking an object is performed. And also for the purpose of reduction of the influence by disturbance as unnecessary objects, a blurred image around center is generated using wavelet transform.View full abstractDownload PDF (2957K) -
Shuang-Hui HAO, Zi-Jiang YANG, Teruo TSUJI1994 Volume 30 Issue 7 Pages 819-827
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSFrom the electromagnetic theory, we know the electromagnetic model of the magnetic levitation system is usually strongly nonlinear, depending on the length of the air-gap. This paper presents a feedback error learning control for a 4-point attraction magnetic levitation system. Firstly, taking account of the nonlinear model of the system, we design the stable closed-loop using a PD controller based on the mechanical model and the normal inverse model of the electromagnetic system (IMES). Secondly, by combining the mechanical and electromagnetic characteristics of the magnetic levitation system with the generalized radial basis functions (GRBF), we present a new kind of hybrid neural network (HNN) to learn the inverse model of the nonlinear system. The HNN has the advantage that the learning algorithm is linear and is therefore fast. At last, experimental results are included to show the excellent performance of the designed control system and it is verified that even in the case of abruptly large changes of the system parameters, the control performances are still very satisfactory.View full abstractDownload PDF (2056K) -
Yosuke HAMADA, Haruaki OTSUKI, Shigeyoshi SAITO, Yuji HATA1994 Volume 30 Issue 7 Pages 828-835
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDisk Drives are widely spread as data storage devices, and recently a demand for large capacity and down-sizing has been increased. In order to meet this demand, head positioning control technique, as one of techniques for achieving high recording density, is expected to improve the head positioning accuracy by reducing tracking error which is caused by disturbance such as bias-force and vibration.
In this paper, we discuss a head positioning control system with a disturbance observer which reduces influence of the disturbance. The control system using a disturbance observer, which has high-pass filter characteristics between disturbance and controlled variable, can achieve high performance of disturbance suppression characteristics.
We confirmed that the head positioning control system using disturbance observer can reduce tracking error caused by vibration through experiments. Still more, we confirmed that the disturbance compensation system using a disturbance compensation table can reduce the variance of switching condition from seeking mode to following mode and is useful to improve settling accuracy.View full abstractDownload PDF (2237K) -
Kazuya ASANO, Takayuki KAJI, Hidemi AOKI, Michio IBARAKI, Saburo MORIW ...1994 Volume 30 Issue 7 Pages 836-844
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents a new control method for stabilizing the molten steel level in the molding process of a continuous casting mill. Securing the stability of the molten steel level will ensure the surface quality of cast slabs by stabilizing the solidification process and preventing surface defects such as pinholes and enclosures. The molten steel level control has generally been carried out by applying a PID feedback control system; however, it is difficult to obtain satisfactory control performance by the conventional control method when various disturbances, such as breakaway deposits in the immersion nozzle and unsteady bulgings, break the equilibrium of massflow in the mold.
The proposed method is based on estimation and cancellation of a disturbance flow, which is defined as the difference between the ingoing and outgoing flow caused by the above disturbances. A disturbance observer is employed to estimate the disturbance flow. Then, the manipulating value which counterbalances the effect of the estimated disturbance flow is calculated and added to the output of the PI controller. This control scheme enables a straightforward and intuitively comprehensible way of designing and tuning controllers, in addition to high control performance.
From the viewpoint of loopshaping, the design procedure is overlooked. The results show that the trade-off between the robust stability and the control performance can be easily incorporated into the design by adjusting a few parameters of the controller. This is helpful for tuning in actual plants.
The control method has been successfully applied to the molten steel control systems in several continuous casting mills, and those systems effectively operate to suppress the effects of the disturbances and to improve the surface quality of the slabs.View full abstractDownload PDF (2699K) -
Tetsuji TANI, Shunji MURAKOSHI, Motohide UMANO, Kazuo TANAKA1994 Volume 30 Issue 7 Pages 845-852
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA practical control method using neural network and fuzzy control techniques is applied to the level control of the tank in a solvent dewaxing plant. The purposes of the control are to stabilize the tank level and to smoothly change the outflow rate from the tank which conflicts with the stabilization of the tank level.
This plant has non-linear characteristics such as refrigerating process and filtering process, so it is difficult to predict the inflow rate to the tank. Especially, the response of the inflow rate to the tank has a large dead time when the feed oil to the plant is switched. Furthermore, the heater installed in the down stream of the tank restricts the outflow rate from the tank.
This neuro-fuzzy hybrid control system consists of three components,
(1) a statistical component, which calculates long-time tendencies of the outflow rate from operation data.
(2) a correction component, which is a fuzzy controller for compensating the outflow rate calculated by the statistical component, and
(3) a prediction component, which uses neural networks to generate suitable control target patterns for the fuzzy controller in advance.
This neuro-fuzzy hybrid controller for the real plant works well not only in steady state but also in transient state.View full abstractDownload PDF (1456K) -
Takao KOKUBU, Kenzou KAMIYAMA, Junichi HAMANO1994 Volume 30 Issue 7 Pages 853-860
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes the application methodology of SFC (Sequential Function Chart) to machines' controls in the tire industry.
With the marvelous progress of micro processing and computer technology, PCs (Programmable Controllers) have become popular and indispensable equipment for machines' sequential control in FA (Factory Automation) area. The complexity and flexibility of machine control relies advancements in PC programming technology. But most of their programs are written by old fashioned Ladder Diagram, which was originally developed as an analogy of wiring circuits. The increasing volumes of programming have revealed major inherent deficiencies in Ladder Diagram. These deficiencies are manifested in programs that are so voluminous and complex that they are practically unmanageable. To overcome these problems, the SFC has been applied as a substitute of Ladder Diagram. Originally the SFC itself has several problems in practical applications. One of the most difficulty in SFC is explanation of interlocking conditions for actuators.
In this paper, authors propose the application methodology of hybrid control by SFC and Ladder Diagram. After evaluation in more than 100 machines, and over 10 kinds of machine applications, the methodology of this hybrid control is proved to be powerful both in machine control and programming. As a result, SFC has a distinct effect on machine controllability, requires less design and maintenance manpower, reduces program and documentation size, eases checkout and start-up work, and saves training time for new personnel.View full abstractDownload PDF (1911K) -
Makoto NAKAMURA, Masahiko KUNIMOTO, Teizoh SHIRAGAMI, Yoshiro SAKAI1994 Volume 30 Issue 7 Pages 861-870
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA fish drying process control system is proposed in the present paper. The proposed system utilizes prediction of suitable drying conditions for the given material fish before drying together with the proper change in weight of material fish with time under that condition. This function of the system has its basis in the performance of a skilled worker in this field. In order to implement a human expertise of this sort, experimental analysis were made so as to find the characteristics which governs the drying process. The proposed system consists of two procedures for producing products of good quality, which are set following human expert's way as mentioned above: 1) The procedure before drying. 2) The one which is executed during drying. The procedure (1) is for setting drying conditions and the prediction of required drying time. In this procedure, the probable change in weight with time is inferred by using fuzzy reasoning. A proper set of drying conditions and the required drying time under that set of conditions are also obtained by using a regression model. The procedure (2) is for more accurate estimation about the progress in drying utilizing the observation during drying. A mathematical model is employed for this purpose. A good agreement between the experimental results and simulation results are obtained, which implies the usefulness of the present control system.View full abstractDownload PDF (2478K) -
Hiroshi NAKAMURA1994 Volume 30 Issue 7 Pages 871-873
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA discrete-time preview-repetitive control algorithm with delays in outputs of manipulated variables and in detections of controlled variables is presented. Experimental results on a motor position control system demonstrated the applicability of the algorithm.View full abstractDownload PDF (343K) -
Tomonobu SENJYU, Hisashi KAMIFURUTONO, Katsumi UEZATO1994 Volume 30 Issue 7 Pages 874-876
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe robust speed control method of DC servo motor with disturbance torque observer is proposed. Influence of estimation error is restrained by feedback gain.
The robust current control method of voltage source PWM inverter with disturbance observer is also presented.View full abstractDownload PDF (324K) -
Tomonobu SENJYU, Katsumi UEZATO1994 Volume 30 Issue 7 Pages 877-879
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, the speed control of ultrasonic motor by hybrid control based on PI (proportional and integral) and adaptive control is discussed. Although dynamic characteristic of the ultrasonic motor varies with time, this method can control the motor speed sufficiently by identification of the motor parameters. The mathematical motor model is also disscussed.View full abstractDownload PDF (358K) -
Toru OMATA1994 Volume 30 Issue 7 Pages 880-882
Published: July 31, 1994
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe have developed an algorithm for computing finger positions for 3-dimensional equilibrium grasps. This paper shows that the algorithm works more efficiently for soft contact fingers. This paper also discusses the effect of two fingers which contact the same region.View full abstractDownload PDF (382K)
- |<
- <
- 1
- >
- >|