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Volume 36, Issue 2
Displaying 1-13 of 13 articles from this issue
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Shoji OKAUCHI, Nobuharu AOSHIMA2000 Volume 36 Issue 2 Pages 137-142
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWe often use induction motor in the hard environment including vibration and high ambient temperature, or in maintenance free operation, because induction motor has durable and simple structure. However, when we use it as servo actuator or accurate speed control motor, we have to equip sensor such as encoder and tachogenerator with the motor control system. And generally those sensor's abilities against bad environment are less than the induction motor itself. So if we can remove these sensors from the system, it'll have more environmental resistance, and the cost will also be reduced. Actually, estimation of the states such as speed or generating torque from the current or input voltage has realized in sensorless vector control for special purpose. However, that needs complex calculations. In our study, we intended to estimate the rotational speed from the motor current instead of speed sensor, easily and rapidly in comparison to former methods. For it, we use the special test current to estimate the rotational speed of induction motor easily without extra speed sensor. To generate this special current, we added sinusoidal voltage to only one terminal of three-phase motor, while delivering normal balanced three-phase voltage to all of three terminals. Then, the phase difference of the current through another two terminals excited by this added input gives us rotational speed of motor. Further, most induction motors are driven by PWM inverter for variable speed operation. So, we attempt the application to PWM operation.View full abstractDownload PDF (1601K) -
Hidenori INAOKA, Masashi SHIMIZU, Akimasa ISHIDA2000 Volume 36 Issue 2 Pages 143-150
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWithin the field of process measurements, there is need of an effective method for accurately measuring unsteady flow rates independent of the state of flow or the characteristics of fluid. In general, an air chamber is often installed as an accumulator in a pipeline to smooth the unsteady flow. In this paper, we propose a new method that utilizes an air chamber for measuring the unsteady flow rate. Volume change of the air chamber is obtained from the measured pressure and the estimated temperature. The estimated temperature is calculated numerically by simultaneously solving the equation of state and the one dimensional approximated heat transfer equation. To evaluate this method, a simple experimental model was employed, and the measured flow rate was compared to the estimated one. Good agreement was achieved between the measured and the estimated unsteady flow rate, and then the accuracy of this method was discussed.View full abstractDownload PDF (3467K) -
Masayuki TANAKA, Li CAO, Shinji OHYAMA, Akira KOBAYASHI2000 Volume 36 Issue 2 Pages 151-158
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe aim of this research is to give a system for cloth handvalue evaluation. A new experimental setup using optical fiber feeler is proposed, and its proper operation conditions are discussed. Small vibration called Stick-Slip of tip of optical fiber feeler when it is scanning on a cloth surface is detected optically, and the output signals are analyzed based on simultaneous probability density function analysis. Characteristic parameters of output signal for each cloth materials, such as silk, cotton and wool, are compared in a characteristic space, and their discrimination algorithm is discussed.View full abstractDownload PDF (2878K) -
Saburo YOKOKURA2000 Volume 36 Issue 2 Pages 159-164
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe false start detection system measures the reaction time associated with the start action of a sprinter and judges the false start automatically. This system must be used for the 100m, 200m, 400m dashes, the 110m, 110m, 400m hurdles and the 4×100m, 4×400m relays of the track and field competition in the Olympic and the world championship competitions. The conventional false start detection system detects the kicking force of a sprinter above the threshold level (about 200 to 400N). The kicking force and the speed, however, depend on the individual sprinter, and becomes the largest expected errors in this system. It is also impossible to measure the kicking force below the fixed threshold level or it's already applied before the starting time.
This paper introduces a new detection system for a sprinter, which subtracts the smoothed moving-averaged and delayed signals from the as-detected signal. This numerical procedure, executed on time by computer, effectively gives the change of the kicking force as a function of the time of the individual sprinter, independent of his force and the speed, resulting in the exact detection of the starting action. This paper explains this new but now practically used false start detection system.View full abstractDownload PDF (2201K) -
Eiho UEZATO, Masao IKEDA, Tick Woon LEE2000 Volume 36 Issue 2 Pages 165-171
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper considers the design of H∞ controllers for linear time-invariant descriptor systems. Firstly, an H∞ norm condition for a stable descriptor system is presented in terms of strict linear matrix inequalities (LMIs), that is, LMIs with no equality constraint. Then, the condition is extended to the H∞ control problem. The existence of an H∞ controller which achieves a specified disturbance attenuation level, is reduced to the feasibility of a set of strict LMIs. The class of desired H∞ controllers in a descriptor form is parametrized by the solution of the derived LMIs.View full abstractDownload PDF (1203K) -
Mitsuo HIRATA, Takenori ATSUMI, Akiyo MURASE, Kenzo NONAMI2000 Volume 36 Issue 2 Pages 172-179
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn the head positioning control of hard disk drives, the information of the head position is embedded radially on the magnetic disk that eliminates the capacity of the hard disk drive. So, if the quantity of this information is decreased, the capacity of the hard disk drive will then be increased. This means that the sampling period in the head positioning control must be lengthened. With long sampling period, it is also expected to cut the cost of A/D, D/A converter and processor for control.
In this paper, we apply the method of the sampled-data H∞ control theory to the following control (fine positioning for read/write data) of the hard disk drive with the aim to control using long sampling period. The sampled-data H∞ control theory can design the discrete-time controller which stabilizes the continuous-time plant with no approximations. For this reason, this method is effective when the sampling period is long.
The obtained performance of the sampled-data H∞ controller is then compared with that of the continuous-time H∞ based controller to show the effectiveness of our proposed method.View full abstractDownload PDF (2516K) -
Tsutomu YOKOZUKA, Takeo ISHIKAWA, Shigeki NISHIMURA2000 Volume 36 Issue 2 Pages 180-187
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSEffects of the air-gap length GL and winding distribution on the magnetic space harmonics BN and torque losses of the capacitor motor are discussed. Relationships between equivalent circuit parameters and GL are investigated with changing GL from 0.35 to 0.15mm. The experimental values of developed torque are compared with calculated values by use of the equivalent circuit parameters. It is shown that the torque ratio, experimental to calculated values, decreases in the region of GL<0.2mm. A method is given for calculating the values of BN caused by the stator slots and winding distribution, and variations of BN as a function of GL are obtained on a test motor. Effects of GL, number of stator slots per pole NS, width of the stator slot, skewed pitch, and winding distribution on the value of BN are investigated.View full abstractDownload PDF (1385K) -
Sotaro SHIMADA, Yuichiro ANZAI2000 Volume 36 Issue 2 Pages 188-194
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes a new type of classifier systems, operon classifier systems (OCS), that develop stable chained classifiers efficiently. To prepare diversity of classifiers that is an essential condition for generating effective chains, OCS is based on niche forming mechanisms such as sharing, covering, and restricted mating. Well-tested chained classifiers are combineed into an operon that tightly maintains subassembries and promotes computational efficiency. Operons keep growing by combining with next families as long as the system performance keeps well. When the performance is aggravated by unsuitable connections, the cut-tail operator that cuts the last-added family from the chain is invoked to regain good performance. OCS is applied to boolean function problems, and results show that OCS develops chained classifiers stably and efficiently.View full abstractDownload PDF (1880K) -
Tomohisa YAMASHITA, Keiji SUZUKI, Azuma OHUCHI2000 Volume 36 Issue 2 Pages 195-203
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, our purpose is to discuss behavior process of players with individual rationality in social dilemma. We propose “Multiple Lake Game with Local Governments” as a social dilemma model, which is the extended game of the environment management game, “The Lake”. In the extenstion of “The Lake”, we introduce new player with individual rationality to prevent players from becoming free-riders. Furthermore, we set multiple lake to make new players compete each other. In experimental results, we confirm that the evolutionary acquired strategies of these players were shown to keep away from social dilemma though all players behave to increase their own payoff.View full abstractDownload PDF (2847K) -
Tadanari TANIGUCHI, Kazuo TANAKA2000 Volume 36 Issue 2 Pages 204-210
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents an approach to fuzzy model following control. The proposed method is a unified approach that contains the regulation and servo control problems as special cases. A new parallel distributed compensation (PDC) to realize fuzzy model following control is presented. The new PDC fuzzy controller mirrors the structures of Takagi-Sugeno fuzzy models that represent a nonlinear system and a nonlinear reference model. First, we present a linearization technique as a basic result. Conditions to linearize the error system between the feedback system and the nonlinear reference model are obtained in terms of linear matrix inequalities (LMIs). It is remarked that the derived LMI conditions may be sometimes conservative. To overcome the difficulty, we present a relaxed approach that employs relaxed LMI conditions. Design examples are illustrated to show the utility of the fuzzy model following control, particularly, the relaxed approach.View full abstractDownload PDF (1311K) -
Kazumoto MORITA, Hisakazu SUZUKI2000 Volume 36 Issue 2 Pages 211-219
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWhen a driver views a display device in the passenger compartment, for example an in-vehicle navigation system, it is conceivable that he or she will repeatedly divert their attention to the display device for short periods of time to read the displayed information or that they will read the information consecutively all at one time. The authors investigated differences in the amount of information acquired for both of these reading methods by carrying out experiments indoors. They investigated by showing observers place names as display data and seeing how many of the place names the observer could remember after the end of the display. The display time conditions for the experiment were following five types
(1) Continuous display
(2) Repeated display for 0.5 second with one-second intervals
(3) Repeated display for 0.5 second with two-second intervals
(4) Repeated display for one second with one-second intervals
(5) Repeated display for one second with two-second intervals
This experiment showed that even when the amount of time that the observer was actually viewing the display was the same, the amount of data acquired by the observer from reading the display repeatedly was greater than the amount of information acquired by reading the display through at one time. In other words, it can be inferred that even during the time while the observer is not viewing the display, information retention and processing is being carried out in short-term memory and that this time is effective for acquiring information.View full abstractDownload PDF (2535K) -
Junso KIMURA, Masami SAEKI, Yukio NISHIMURA2000 Volume 36 Issue 2 Pages 220-222
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA controller which robustly stabilizes the plant with an input delay has a structure of predictor. In this paper, it is shown that a simplified predictor can also robustly stabilize the plant.View full abstractDownload PDF (419K) -
Shinji SHINNAKA2000 Volume 36 Issue 2 Pages 223-225
Published: February 29, 2000
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents a new mathematical model with parallel core-loss factor for controlling salient-pole synchronous motors, which is established based on a unified stator model of AC motors. Proposed model is described in general frame and is composed of three basic and consistent equations such as differential equation presenting electro-magnetic dynamics, torque equation and energy-transmission equation.View full abstractDownload PDF (463K)
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