In the control technical committee in the Institute of Electrical Engineers of Japan (IEEJ), enormous numbers of data-driven control and performance-assessment methods have been studied and developed so that control control performance is enhanced. In this paper, data-driven control and performance-assessment methods studied in the control technical committee are introduced. Furthermore, this paper introduces two methods of performance-driven PID control systems, the PID parameters of which are tuned automatically such that user assigned control performance is achieved. The effectiveness of the designed methods is demonstrated by the experimental studies, and the role played by the control technology in the green innovation is shown through the control results.
IGBT as the representative of the MOS-bipolar device has widely used for power conversion system, because it has the high controllability as MOS gate device and high breakdown voltage with low ON resistance as bipolar device simultaneously. IGBT has the potential to satisfy so many requirement such as low loss, low switching noise, high breakdown voltage, low cost, high efficiency and high reliability. In this paper, we summarize recent topics of IGBT and its analysis from the above points of view.
Efficiency and controllability of power electronics is highly affected by power device performances, such as low on-resistance and high speed switching. In recent years, SiC, GaN, and diamond are expected to be used for making superior power devices, since Si device performance is approaching the material limit. In this paper, we review recent advances of the new material devices, by picking up some papers presented in power-device related conferences and journals.
Contact doping effects in p-channel dinaphthothienothiophene (DNTT) thin-film transistors with a bottom-gate, top-contact configuration were investigated with both experimental and numerical approach. Characteristic variation in transistor parameters such as the gate threshold voltage and the field-effect mobility for devices with various channel lengths was suppressed by the contact doping with tetrafluorotetracyanoquinodimethane (F4TCNQ) as an acceptor dopant. The gate-voltage dependence of contact resistance and channel resistance was also evaluated separately to examine the contact doping effect in detail. In addition, device simulation considering a Schottky barrier at a metal/semiconductor interface successfully reproduced the experimental current-voltage characteristics by using a hole concentration of the active DNTT layer in the order of 1017cm-3, which was estimated by capacitance-voltage measurement for a metal/insulator/semiconductor capacitor structure. This study suggests the importance of establishing both the carrier doping and carrier concentration measurements toward realizing practical applications of organic transistors.
In this paper, a synthesis of a RiCR filter with flat passband characteristics is proposed. Because the RiCR filter include no inductors, we can reduce the required elements when we realize the filter using OTA's and C's. The transfer function Tc of the proposed circuit is obtained through the frequency transformation based on the special case of BLLT. Its prototype transfer function Tb is also a complex transfer function and has multiple transmission zeros placed at ω=-1 and 1. The kernel function of Tb is obtained by an analytical method not by numerical calculations depending on computers as used in many of the conventional methods. The proposed filter can be designed through a graphical method based on the relationship among ωc/bw (selectivity), ωc (center frequency) and Amin (minimum attenuation). The proposed circuit can be composed of 2n+4 OTAs and 2n capacitors. As an example, a 5th-order RiCR filter is designed. The proposed filter is compared with the complex Butterworth filter from the view point of the frequency characteristics and the number of the required elements. It is shown that the proposed RiCR filter has maximally flat response in the passband.
Recent years, Japan is facing a “Super Aging Society”. To realize care prevention, various rehabilitation and training machines are developing. In this research, we try to control a linier drive actuator having two step operation modes depending on the load of the actuator, using adaptive learning force controller. We propose a training unit using two proposed linear actuators. The results of metering experiments using proposed equipment has shown.
It is well known that the workload for propelling a manual wheelchair is affected by many factors. Some of them are related to the wheelchair itself, and the others are those that are not related to the wheelchair. From many users' experiences, the tire pressure has been thought as the most effective one in the former factors. In these circumstances, the purpose of this research is to clarify the relation between the tire pressure of the driving wheel and the required driving force in manually propelled wheelchairs. Then, a clinical testing to measure required driving forces in different tire pressures at a manually propelled wheelchair has been carried out by using a standard wheelchair in conformity with the Japanese Industrial Standards (JIS). The result of the testing indicates that the required driving forces increased according to decrease of the tire pressure. This objectively reveals that appropriate tire pressure in manually propelled wheelchairs is the one of important factors to reduce driving force.
Human monitoring technology (HMT) is one of significant engineering tools for the development of human society and brought life innovations with the change of the times. In this paper, after the historical background of a HMT is mentioned briefly, a monitoring system for kindergartners, Kinder-Guardian system (KG), is introduced as an example of active studies in the health care field, which is a recent main market for the HMT. The KG system aims to both manage the health-activities of kindergartners and support the kindergarten staffs and utilizes an activity recognition technique based on a data clustering method. An innovation using the HMT including the KG cannot be created only by developing engineering technologies because a practical strategy suitable for all users is required with consideration of their explicit and implicit requests. This paper therefore presents a set of processes of the strategy that consists of the field exploration, a development of the clustering algorithm, a proposition of the system management, a prototyping of the hardware, and user evaluations in case of the KG.
In many cases, real plants have time-delay in control inputs. For example, PID controllers are designed by approximating the plant as a 1st order+time delay. In such plants, effects of feedback control inputs do not directly appear and the control of the systems is difficult. To control systems having time-delay effectively enhances safety of systems, makes mechanical systems applicable to caring of humans safely and contributes life-innovations. If a way to calculate the sum of squared tracking errors of outputs is obtained, then the minimization of the sum is easily calculated and an optimal control for such systems is straightforwardly obtained. This paper proposes a calculating method for the sum of output errors by (1) expressing the time delay system in a state-space equation, (2) calculating the sum by solving a Lyapunov matrix equation and (3) in solving the matrix equation, obtaining mathematical expressions of converted equations to linear equations and a matrix inversion by using symbolic computation software in beforehand. Also, for an example, optimal PID gains for 1st-order + time delsy system is obtained and numerical simulations are given.
In this paper, for quantitatively comparing batting motions of Non-expert and of expert baseball players, motion analysis methods using several bio-instrumentation systems are discussed. In this analysis, at first, all member of baseball club are devided into expert players or Non-expert players by the manager of the high school baseball club members. Next, a batting speed, a center-of-gravity movements, a rotating angle of body trunk axis of players and a ground reaction force are measured by two force plates and ten high-speed cameras within motion capturing systems. By analyzing and processing statistically these data, a common feature of expert players is extracted.
Generally, athletes and artisans have a tacit knowledge, which is impossible to tell other persons directly, from a lot of practice and experience. In this paper, we measure a bat swing motion by using 3D motion capturing systems, and analyze a muscle power of a lower limb. In the analysis, we estimated a muscle power of a lower limb of regular players and beginner players in high school baseball by using kinetic analysis systems, at first. And, under assuming that common features of each expert are one of the common elements of the tacit knowledge, extracted common features of each expert players by comparing these data. As a result, we find characteristic differences of muscle power between experts and beginners.
Japan's robot industry is rapidly evolving from around 1980, Japan came to be referred to as a robot powerhouse. Also, it has contributed greatly to the development of Japan's manufacturing industry. However, Japan has reduced the workforce by the declining birthrate and aging population, also it has many problems such as the intensification of international competitiveness. As a solution to these problems, the robotic technology has attracted attention. The report of the “Robot new strategy” by the Ministry of Economy, Trade and Industry in Japan, innovation by using robotic technology has been marked as important for sustainable growth. On the other hand, the notice has been Japanese elementary school curriculum guidelines in March 2008, “cleaning activity” has been described as special activities in the school. However, it is a heavy burden for teachers to instruct students to clean in the elementary school.
Therefore, in this study, the educational material to support the motivation of picking up rubbish has been developed for elementary school students. Furthermore, in order to evaluate the effectiveness of the proposed educational materials, it is used to support the motivation of picking up rubbish at two elementary schools.
In this paper, a design method of an almost strictly positive real (ASPR) based output feedback control with an adaptive predictive control as a feedforward input is proposed. The proposed method can design a stable and simple adaptive predictive based control with higher control performance for systems with uncertainties. The effectiveness of the proposed method is confirmed through numerical simulations and practical experiments for a two-tank process.
In control system, it is necessary to maintain a high control performance. However, it is difficult to maintain the performance by retirement of skilled workers and loss of their knowhow. Therefore, from the perspective of green innovation, the problem must be solved by automatic control. In recent years, several researches of control performance assessment have been proposed. A performance-driven controller that redesigns the controller when detecting that the control performance is deteriorated has been proposed. This method is based on a result of the control performance assessment, however, it does not consider a deterioration cause of the control performance. Here, the control performance deterioration caused by disturbance and/or system variant is considered as an example. When the reason of a poor control performance is caused by disturbance, the incorrect parameter adjustment may lead more poor control performance, eventually, the control system may fall into an unstable state. In this paper, the reason of the control performance deterioration is detected by Support Vector Machine in advance, and the controller is redesigned only when the control performance deterioration is caused by system variant. Thanks to this strategy, the incorrect parameter adjustments are avoided, and a high control performance can be maintained.
Studies on Demand Response (DR) have been getting more active since the Great East Japan Earthquake in 2011. In particular, the Peak Time Rebate (PTR) type DR, which motivates consumers by providing rewards to reduce electric power consumption during periods of high electric demand, is expected as one of the effective demand control methods, which does not impose any burden on consumers. However, there is few reports on PTR. Under the circumstances, the authors designed a PTR-DR system, and then have analyzed responses of the consumers who have been participating in the demonstrative field test in Kyushu area. In this paper, the authors present the results of analysis on the consumers' responses. Moreover, the authors suggest an effective design of PTR-DR based on the demonstrative test.
This paper considers a PID gain tuning method based on generalized minimum variance evaluation. The method derives the PID gains for reducing the variance of the generalized output from regulatory control data disturbed by colored noise. Advantages of the method include the use of normal operating data with no additional experiment for PID tuning. Numerical examples for a CARIMA (Controlled Auto-Regressive Integrated Moving Average) model and a liquid level control model show the proposed method is effective for not only colored noise but also stochastic disturbances combined with periodical rectangular deterministic signals. The simulation results demonstrate that the proposed approach has robustness to model mismatch of disturbance characteristics.
The excavation disk cutter is used for the tunnel boring machines because of the noise abatement and/or the safety. However, the hydraulic control of the force for the bedrock is not driven by the automatic control because the advantage is not clear. So, this paper considers the efficiency of the automatic control which drives the excavation disk cutter. Experiments are carried out by using a model excavator with excavation disk cutter for tunnel boring machines. The experimental results are assessed by MV-index and compared with the estimated output of minimum variance control. The application merit of the automatic control is evaluated by this procedure.
This paper focuses on a robotic lighting system composed of multiple LED lights, each of which has a pan-tilt mechanism and a distributed controller. For the system, we consider the control of pan-tilt angles such that the actual illuminance distribution is similar to a desired one. We first formulate the design problem of distributed controllers which determines pan-tilt angles of LED lights by using the information on desired illuminance distributions. Then, we propose distributed controllers based on the idea of a coverage control method for multi-agent systems. Furthermore, we develop an experiment system with 16 LED lights. Finally, the effectiveness of the proposed control method is confirmed through simulation and experiments with the developed system.
Of the 82 thousand upper-extremity amputees in our country, the majority use prosthetic hands. Recently, research and development of myoelectric hand have come to the forefront. However, due to the usage of multiple electric actuators, the myoelectric hand is heavy, structurally complicated and expensive. Thus, the authors propose a pneumatically-driven prosthetic hand with bellows incorporated in the joint. A remarkable point of the proposed prosthetic hands is grip force, averaging 11.0 N with 5 fingers. This grip force exceeds that of general pneumatically-driven prosthetic hands. Also it is lightweight of 240 g, reducing user fatigue. The hand's basic control performance showed quick response to the reference angle and pressure. In the next grasping experiment using EMG envelope, the test subject with this prosthetic hand was able to grasp a 500 ml (500 g) PET bottle. The test subject could grasp an eraser, a flexible rubber ball, and a paper cup. Moreover, this prosthetic hand is equipped with tactile feedback functions enabling users to perceive contact or reactive force from physical objects.
In this paper, contents of tennis games are recognized automatically. 3-D positions of a ball and players are detected by using stereo camera method. The system detects ball bounces on a court and shots by players using vector directions of the ball velocity. The game ends are determined by the ball velocity and its position, and the game sequences are recognized automatically. The system also detects the shot style - forehand, backhand, volley, smash stroke - by using the existence of bounces before shots and the positional relation of the ball and the player's. Experiments were executed by using 7 game video data, and the automatic recognition results showed good coincidence with the results of human judgments.
It is commonly believed that by drawing human's attention to particular objects, human activity can be effectively facilitated. The aim of this paper is to propose a novel video modification method for directing gaze to specific objects of interest, using a saliency map model based on L*a*b* color space. First, we compute the saliency map, and modify the L*a*b* components of each frame based on the obtained saliency map for adjusting saliency value. And then, we repeat this process until the specified objects has become the most salient in each frame. By applying the our attention retargeting method to a video, we can obtain the video in which the specific object shows the highest saliency.
Near-carrier phase noise characteristics of the reference oscillation circuits in the mobile communication systems constantly need to be improved. We have developed the oscillators for the SC-cut with the partial electrodes, and it succeeded in reducing the phase noise. Experimental results show that the phase noise was greatly improved when the partial electrodes were used.
A TFT (Thin film transistor) driving-circuit for active-matrix was discussed to enlarge FEDs (Field emission display) using an MIM (Metal-insulator-metal) -cathode. The cathode has a thin insulator sandwiched with 2 conductive films, and the capacitance is proportional to the display size. In the simple matrix display, it is impossible to charge the wirings connected to the MIM-cathode to specification voltage within scanning time with enlarging of the display. We introduced an active matrix method, where the MIM-cathode was charged with the current switched by an oxide semiconductor TFT connected to DC power supply. The capability of 55-inch FHD (Full high definition) display was evaluated assuming the mobility of the TFT to be 10 cm2/Vs. As a result, it was shown that the current can be supplied to the MIM-cathode sufficiently by using the driving transistor Td with channel length of 8 µm and width of 100 µm. The wirings for DC power supply and GND are formed in both horizontal and vertical directions. The voltage-drop at the central portion of the display generated by the wiring resistance can be suppress to be less than 0.2 V, and the voltage has little influence on image quality. The performance of the 55-inch FHD display driven by active matrix with oxide semiconductor TFT was confirmed.
It is known that the contingent negative variation (CNV) is not seen with sleep suppression, and the production mechanism cannot recover at once. In this study, we employed the experiment of 36 hours sleep suppression. Stabilograms, flicker values (FV), and Stanford Sleepiness Scale (SSS) were measured every 90 minutes for 51 hours except for their 12 hours sleep. As a result of the time sequences in the FV and SSS, vigilance remarkably decreased 22.5 after the onset of this experiment, which was regarded as an evidence supporting CNV disappearance with the sleep suppression. Sway value with subjects' eyes closed was the greatest 22.5 hours after the onset of this experiment. The body sway during the CNV disappearance is interesting because we can study the biological control by the subconsciousness, where the body sway is expressed by stochastic differential equations (SDEs). The authors also employed numerical analysis of the SDEs that were obtained from the time series data of the body sway.