For the Okinawan economy to grow independently, it is essential to create new businesses; this will require the cultivation of technologies that will form the basis for those businesses, as well as require the training of technicians and researchers. To promote the creation of new businesses and innovation that are “Unique to Okinawa”, the Institute of Electrical Engineers of Japan set up a cooperative research committee to develop Okinawa-style robot embedded systems. We proposed the concept of Okinawa-style robot-embedded systems. To realize this concept, we organized technical meetings to promote research. Now, our research focuses on developing a playback-type navigation robot for use in land and air. Also our research focuses on developing an underwater robot for conserving marine life in the Okinawa sea. It is necessary to conduct proper measurements, observations and sampling in water. To successfully perform these tasks, we needed to develop an underwater robot. We have made efforts in developing hardware, software, and application for embedded techniques. We suggested CIOS (Coarsely Integrated Operand Scanning) and BF (Bilateral Filter) hardware implementation. Moreover, we developed welfare equipment to support disabled children through software.
This paper describes the development of a visual tracking method of an underwater vision system installed into a UVMS (underwater vehicle-manipulator system) to manipulate ocean-floor organisms such as acanthaster. First, an execution procedure of UVMS for approaching the target is shown. Next, a novel and robust target tracking method by using particle filter framework in order to achieve the procedure is proposed. We applied the proposed method to real video images, and examined its effectiveness by comparing it with other methods. The results of some experiments that evaluate the performance of the developed method are given.
Using the animations made as learning materials is an effective learning method. However, we thought that the more effective learning method is to create them by the learner themselves. The learners themselves must learn the item and must understand it well to create and present to the others. The purpose of this study is to propose the collaborative learning technique by co-creating the animations made as learning materials. We used the T2V player to create and view an animations based on TVML a TV program description language. As a result, we could create the animations with the learning effect for National Examination for Information Processing Technicians, and there was the learning effect at the creation process.
A bilateral filter (BF) is a nonlinear filter that performs edge-preserving smoothing. In recent years, BF has been used in a wide variety of fields such as computer vision and computer graphics, and its applications include medical image processing. However, as compared to other filters, BF has large computational and time requirements. BF can be effectively used as a pre-processing step to speed up processing. In this paper, we consider a BF implemented at a one-chip circuit scale on a field-programmable gate array (FPGA). Furthermore, we aim to speed up floating-point pipelined arithmetic operations and processing by adopting a multiplication-based divider. The results show that hardware processing is approximately 20.93 times faster than software processing. Therefore, high-speed applications using BF are possible without the need for large equipment such as workstations or GPUs. Finally, it is suggested that real-time processing is feasible if a BF is applied as a pre-processing step.
The main subject of this research and development is to make the research and development and proving experiment of the underwater communications (underwater visible light communications =VLC) with the premise of utilization of VLC for tourism and environmental protection, in the oceanic conditions of Okinawa area (Zamami-village) that obtains one of the highest popularities as a diving spot which has the highest transparency of water and gathers lots of coral and fish. Radio communication is rarely used as a communications tool underwater because the attenuation rate of radio signal is high. At this moment the only communications tool available in the water is the sonic (ultra-sonic) communications, though, it has not spread out among the divers since it is subject to noises from the reflections of water surface or the bottom of the sea and the handling is not that easy. Another disadvantage of this mode of communication is that it is very difficult identity the speaker when several divers are present in the same area. With the underwater VLC device, most of the underwater communications problems are already solved with the following reasons: (1) easy to move and act without cables; (2) it is easier to catch the other buddy's words since it doesn't spread out like sonic communications; (3) conversation is much easier since the buddy can recognize the speaker with eyes.
This paper describes an attempt to develop an automatic unmanned aerial vehicle (UAV) control system for emergency rescue and investigation. A cascade classifier system using Haar-like features for object recognition from a free viewpoint is also presented. Conventional emergency rescue systems have a shortcoming in terms of their performance. Thus, we introduce an automatic UAV control system in order to overcome the shortcoming of conventional emergency rescue systems in an emergency situation. The proposed system involves two processing stages. One involves a capturing and recognition of target objects, and the other involves controling the UAV using digital intelligence. Object detection in many types of images as well as real-time simulation methods continue to be one of the most common techniques for information processing and applications. The fundamental concepts of the proposed system and some experimental results obtained by using related processing techniques are also described.
In the recent years, welfare equipment has been developed to support the disabled children. We are developing a joystick mouse to enable computer operation by disabled children. In this study, we develop such a joystick mouse using a microcontroller. In addition we intend to improve the operability of the equipment by ensuring software-like assistance. We believe that the equipment can respond flexibly to the difference in disabilities a disabled child, by providing software-like assistance. From the result of the experiment, we confirmed that the proposed method is effective in improving the operability.
Much research and development on Blimp robots is focused on their indoor use, with many efforts seeking to develop them for indoor surveillance or advertising. However, it has not get been experimentally proved that these robots can be controlled reliably. Thus our study, aims to demonstrate the stability of autonomous flight control using Table-Driven Navigation (TD Navi) to instruct a Blimp robot of a predetermined path. Through experiment, we establish that stabilized control is possible using TD Navi with PID control.
This paper describes the development of a mobile robot system capable of autonomously traveling along a path for a long duration. First, for robot movement, 20-cm-long QR codes were affixed to the ceiling. The codes are used as landmarks for the robot movement path. These landmarks are recognized by the camera mounted on the robot, and they visually guide the robot to the destination. Therefore, the robot is a completely autonomous mobile robot. Next, to support long-duration tasks in customer space, we designed the space to automatically supply power to the robot. We also confirmed that during the eight hours of travel testing, the robot continuously traveled along the path without any problems.
This paper proposes a decoupled bilateral control based on a modal space observer. In a conventional bilateral control system, the structures of master-slave systems are not considered. This paper shows that a force controller and a position controller in a bilateral control system are interfered when the structures of the master-slave systems are different. In order to solve this problem, a bilateral control system based on a hybrid matrix has been proposed previously. However, the computational process for calculating the hybrid matrix becomes complicated when the number of DOF of master-slave systems is increased. In the proposed method, a nominal equivalent mass matrix with respect to the modal space is used, and the interfered terms are estimated and compensated for using a modal space observer. Therefore, a simple control structure is realized using the proposed method. The performance of the proposed method is compared with that of the conventional methods by simulations and experiments, and the validity of the proposed method is verified.
The paper proposes a method to evaluate cooperative skills of individuals during machine operation. A formula to estimate the skill level was derived by investigating eye movements and performing statistical analyse of them. The analysis results in the training process of virtual vehicle operations confirmed that the velocity and distance of a saccade reflect well the cooperation skill with the correlation coefficients ranged from 0.48 to 0.76; hence, these characteristics were adopted as factors to estimate the cooperation skill level. These factors were used to conduct a principal component analysis and an outlier test to derive a canonical (not depending on individual differences) formula for skill estimation. The estimation accuracy was verified, and it was confirmed that the estimation model is effective when the correlation coefficient ranges from 0.56 to 0.84.
This paper discusses a new circuit configuration and a control method for a single-phase AC-DC converter with power factor correction (PFC). The proposed converter can achieve low total harmonic distortion (THD) for the input current, and at the same time, it can use an active buffer to control the low output DC voltage ripple. The proposed converter does not require large smoothing capacitors and large inductors, which are conventionally required in such converters to decouple the power ripple with a frequency twice that of the power supply. The buffering energy is maintained by a small capacitor, which controls the voltage variation in the capacitor using the active buffer. In this paper, the fundamental operations of the proposed converter are confirmed by experimental results. From the experimental results, it is found that the input current THD is 1.44%, the ratio of the output voltage ripple is 6.33% and the input power factor (PF) is greater than 99%. In addition, a maximum efficiency greater than 96% is obtained in the prototype.
This paper proposes a high-efficiency control method for an insulated DC-DC converter with a phase-shift inverter for a single-phase grid-connected photovoltaic generation system. The proposed control method for the inverter output power is regulated by controlling each phase angle of the inverter leg and by controlling the frequency. Moreover, the inverter switching frequency is controlled by changing the input current of the main circuit, and soft-switching can be realized by controlling the frequency. The phase angle of the inverter is controlled by the output voltage of the main circuit. The validity of the proposed method is confirmed via the experimental results. Using the proposed method, we find the efficiency that improved by a maximum of 3.6% as compared with the case of the conventional method.
In this paper, we discuss the solution of the linear system of equations derived from a finite element electromagnetic field simulation of a practical model in which the electromagnetic field is analyzed with effects of external circuits. To solve the linear system of equations efficiently, we introduce two preconditioning techniques recently proposed for Krylov subspace method. One is folded preconditioning and the other is A-phi block IC preconditioning. The A-phi block IC preconditioning is also one of folded preconditioning methods. Through practical simulation models, we examine these preconditioning techniques and confirm their effectiveness. Furthermore, we present a strategy for selecting the appropriate preconditioning technique, focusing on the magnitude of nonzero elements in non-diagonal blocks of the coefficient matrix.
DC tests can accurately determine the unsaturated synchronous machine equivalent circuit constants by a simple standstill test. This paper presents two improved DC tests that account for the magnetic saturation of the stator iron core by the main flux. These tests are tentatively named Step Response Test (I) and Step Response Test (II). The former can predict the incremental d-axis synchronous reactance by performing a Fourier transform of the voltage and current measured when a small step voltage is applied to the two armature terminals as a field current flows. The latter can determine the incremental d- and q-axes synchronous reactances by the same Fourier transform of the voltage and current measured when a small step voltage is applied to the two armature terminals as an armature current flows. In addition, this paper introduces a new method to calculate not only the static d- and q-axes synchronous reactances but also the no-load saturation and short-circuit characteristic curves. This new method does not require the results from any additional tests including the rotational driving tests and dimensional information, which can only be obtained from the manufacturer. To demonstrate the validity of the proposed method, results of an experiment using 10-kVA laminated synchronous machines with damper winding are presented.
This paper describes a new method for estimating the rotor position and speed of a surface permanent magnet synchronous motor based on a model reference adaptive system, and a technique to improve the estimation performance of the method. A rotor position estimation system should show the same transient response at all speeds and should be unaffected by motor parameter variations. First, this paper proposes a sensorless control structure with a winding resistance estimator. Second, it is shown that the relationship between the estimated rotor speed and the actual rotor speed in the estimation system is nonlinear, and expressions are derived for estimating the rotor position and speed by using nonlinear compensation and the winding resistance. In addition, a winding resistance estimator with improved performance is described. Several experimental results are presented to show the performance of the proposed method.
In designing solid-pole synchronous machines, it is important to take into account the surface eddy-current losses in the field pole cores. In this study, a solid-iron ring specimen is adopted as an approximate model of solid pole surfaces in order to conduct a fundamental study of the surface losses. The influence of the minor hysteresis loops on the losses under DC-biased magnetization is investigated. The losses in the ring under DC-biased magnetization are measured and analyzed by finite element analysis (FEA). The losses computed by the FEA considering minor loops are nearly the same as those measured. In contrast, the eddy-current losses computed by FEA without considering minor loops are considerably inaccurate because the incremental permeability is overestimated and the skin depth is underestimated. It is important to consider hysteresis for the accurate calculation of the surface eddy-current losses under DC-biased magnetization.
Light-emitting diode (LED) lights are expected to improve the visibility of emergency vehicles. We propose a two-stage method for evaluating the flash patterns of LED warning lights. In the first stage, we identify the visibility of many kinds of flash patterns using the mental measure of “distinctness” from Scheffe's paired comparison. In the second stage, we select a few kinds of flickering patterns with higher distinctness out of patterns used in the first stage, and obtain the reaction time to their patterns with high accuracy. We conducted experiments on 3DCG simulation by creating CG animations as stimuli in which LED lights flicker in various patterns. The results of the two-stage evaluation using 11 flash patterns indicated that the mental measure of distinctness of the LED flickering patterns is correlated to reaction time. We propose that the most-visible flickering pattern can be designed using this method.
A new soft switching circuit system with a lossless snubber circuit as an auxiliary circuit in the soft switching circuit is proposed in this letter. Soft switching operation is achieved for the main switch and the auxiliary switch. Moreover, zero current switching operation in the turn-off of the main switch is also realizable in the proposed circuit by using the charging voltage of the auxiliary capacitor in the lossless snubber circuit.
Our research focuses on power electronics and electromagnetic field analysis. Especially, power electronics themes are power control for power distribution system, matrix converter, AC-DC converter, motor drive system. Furthermore, electromagnetic field analysis themes are design for electromagnetic actuators and development of analytical methods.