Showing papers by "Mitsubishi Electric published in 2002"

Dexterous anthropomorphic robot hand with distributed tactile sensor: Gifu hand II

Abstract: This paper presents an anthropomorphic robot hand, called the Gifu hand II, which has a thumb and four fingers, all the joints of which are driven by servomotors built into the fingers and the palm. The thumb has four joints with four-degrees-of-freedom (DOF), the other fingers have four joints with 3-DOF, and two axes of the joints near the palm cross orthogonally at one point, as is the case in the human hand. The Gifu hand II can be equipped with six-axes force sensor at each fingertip, and a developed distributed tactile sensor with 624 detecting points on its surface. The design concepts and specifications of the Gifu hand II, the basic characteristics of the tactile sensor, and the pressure distributions at the time of object grasping are described and discussed herein. Our results demonstrate that the Gifu hand II has a high potential to perform dexterous object manipulations like the human hand.

Control system and user interface for network of input devices

Abstract: Apparatus, methods, and systems for centrally and uniformly controlling the operation of a variety of devices, such as communication, consumer electronic, audio-video, analog, digital, 1394, and the like, over a variety of protocols within a network system and, more particularly, a control system and uniform user interface for centrally controlling these devices in a manner that appears seamless and transparent to the user. In a preferred embodiment, a command center or hub of a network system includes a context and connection permutation sensitive control system that enables centralized and seamless integrated control of all types of input devices. The control system preferably includes a versatile icon based graphical user interface that provides a uniform, on-screen centralized control system for the network system. The user interface, which includes a visual recognition system, enables the user to transparently control multiple input devices over a variety of protocols while operating on a single control layer of an input command device. In an alternative embodiment, the control system also enables gated signal pass-through control while avoiding signal jamming.

A Monte Carlo algorithm for fast projective clustering

Abstract: We propose a mathematical formulation for the notion of optimal projective cluster, starting from natural requirements on the density of points in subspaces. This allows us to develop a Monte Carlo algorithm for iteratively computing projective clusters. We prove that the computed clusters are good with high probability. We implemented a modified version of the algorithm, using heuristics to speed up computation. Our extensive experiments show that our method is significantly more accurate than previous approaches. In particular, we use our techniques to build a classifier for detecting rotated human faces in cluttered images.

A new torque and flux control method for switched reluctance motor drives

Abstract: Switched reluctance (SR) motors have an intrinsic simplicity and low cost that make them well suited to many applications. However the motor's doubly salient structure and highly nonuniform torque and magnetization characteristics lead to the inability to excite the motor using conventional AC motor waveforms, or apply established AC motor rotating field theory to the motor. Furthermore, high torque ripple is inherent in the motor unless a torque ripple reduction strategy is employed. Thus, control of the motor is difficult and complex compared to other machines. Previous methods of control have fallen into two main categories: those which use a simplified linear model and those which account for the motor saturation. The simplified linear model schemes have the advantage of simplicity and tractability but are inaccurate in most practical SR drives, whereas the nonlinear schemes have the problem of high complexity and computational expensiveness which makes real-time implementation difficult. To overcome these problems, in this paper, a novel control method for the SR motor is derived from analysis of the nonuniform torque characteristics of the motor. The control method applies the philosophy of direct torque control (DTC). Unlike previous direct torque control schemes for the SR motor drive, the new method does not involve short flux patterns, a change of the motor winding configuration, or the use of a bipolar current drive. Thus, the scheme can be conveniently implemented on any normal type of SR motor drive. In addition, the scheme overcomes the problems associated with torque ripple control in the SR motor by regulating the torque output of the motor within a hysteresis band. Furthermore, the scheme is very simple and can be implemented in real-time with low cost microprocessor hardware.

Novel vector control system using deadbeat controlled PWM inverter with output LC filter

Abstract: This paper proposes a novel high-performance vector control system of an ac motor using a low-switching-frequency (2 kHz) pulsewidth-modulation voltage-source inverter with an output LC filter. Excellent high-speed response characteristics of the LC filter output voltage have been realized using a novel deadbeat control algorithm. As for the experimental results, the torque current response that is similar to the response of the conventional system without an LC filter has been obtained. In addition, it has been confirmed by simulation that errors of the LC filter constants within /spl plusmn/10% can be permitted.

High-efficiency and low acoustic noise drive system using open-winding AC motor and two space-vector-modulated inverters

Abstract: The combining of the outputs of two inverters using interphase reactors is a widely used method for supplying large AC drives rated at more than several thousands kilowatts. Certain drawbacks are associated with this method, such as high acoustic noise and high losses due to the interphase reactors. To overcome these problems, the authors propose a new high-efficiency drive system using an open-winding motor and two space-vector-modulated inverters. This configuration consists of a three-level inverter with switching at once every cycle and a two-level inverter of about 1-kHz switching frequency, connected, respectively, to the opposite terminals of the open-winding AC motor. With the proposed configuration, good current waveforms, high efficiency, and low acoustic noise can be obtained.

Mobile body network

Abstract: A mobile body network as a sub-net constituting a composite IP network comprises a home agent server managing identifiers of a plurality of mobile terminals subscribed in this mobile body network, and a plurality of IP tunnel routers. When a mobile terminal has moved to another sub-net constituting the composite IP network, the home agent server accepts from the mobile terminal, transmission destination information required for transmission to the mobile terminal and delivers IP tunnel setting information specifying the mobile terminal and the transmission destination information to a plurality of IP tunnel routers. Upon reception of an IP packet to be transmitted to the mobile terminal, each of the IP tunnel routers transfers the IP packet in accordance with the IP tunnel setting information without using the home agent server.

Searching for dark matter halos in the suprime-cam 2 square degree field

Abstract: We report the first result of a weak gravitational lensing survey on a 2.1 deg2 Rc-band image taken with a wide-field camera (Suprime-Cam) on the prime focus of the 8.2 m Subaru Telescope. The weak lensing mass reconstruction is applied to the data to search for dark matter halos of cluster scale M ≥ 1014 M☉. The reconstructed convergence field is divided by 1 σ noise to obtain the signal-to-noise ratio (S/N) map of the detection. Local maxima and minima are searched on the S/N map, and the probability distribution function (PDF) of the peaks is created to compare with model predictions. We found excess over noise PDF created from the randomized realization on both the positive and negative sides. Negative peaks imply the presence of voids in the dark matter distribution, and this is the first report of the detection. Positive peaks, on the other hand, represent the dark matter halos, and the number count of the halos on the 2.1 deg2 image is 4.9 ± 2.3 for S/N > 5, where the Gaussian smoothing radius of the convergence map is 1'. The result is consistent with the prediction assuming the Press-Schechter mass function and the Navarro-Frenk-White halo profile under the cluster-normalized cold dark matter cosmology. Although the present statistics are not enough because of the limited field of view, this work demonstrates that dark matter halo count via weak lensing is a promising way to test the paradigm of structure formation and the cosmological model.

High aspect pattern fabrication by nano imprint lithography using fine diamond mold

Abstract: Nano imprint lithography is an attractive fine lithographic method to obtain nano patterns by using low cost process and materials., Various applications have been demonstrated to utilize this fine method. One of the advantages of nano imprint lithography is that a wet development process is not required, which sometimes causes sticking errors by surface tension during wet development process. On the other hand, there is no fear of such defects by imprint lithography because a resist is mechanically deformed and released. We have demonstrated high aspect ratio pattern fabrication as high as 6.0 with 200nm in line width. But the mold is fabricated using thin Si substrate and anisotropic wet chemical etching, which cannot fabricate voluntary patterns by crystalline axis dependence.

Automatic generation of subword units for speech recognition systems

Abstract: Large vocabulary continuous speech recognition (LVCSR) systems traditionally represent words in terms of smaller subword units. Both during training and during recognition, they require a mapping table, called the dictionary, which maps words into sequences of these subword units. The performance of the LVCSR system depends critically on the definition of the subword units and the accuracy of the dictionary. In current LVCSR systems, both these components are manually designed. While manually designed subword units generalize well, they may not be the optimal units of classification for the specific task or environment for which an LVCSR system is trained. Moreover, when human expertise is not available, it may not be possible to design good subword units manually. There is clearly a need for data-driven design of these LVCSR components. In this paper, we present a complete probabilistic formulation for the automatic design of subword units and dictionary, given only the acoustic data and their transcriptions. The proposed framework permits easy incorporation of external sources of information, such as the spellings of words in terms of a nonideographic script.

Efficient scheduling of conditional behaviors for high-level synthesis

Abstract: As hardware designs get increasingly complex and time-to-market constraints get tighter there is strong motivation for high-level synthesis (HLS). HLS must efficiently handle both dataflow-dominated and controlflow-dominated designs as well as designs of a mixed nature. In the past efficient tools for the former type have been developed but so far HLS of conditional behaviors lags behind. To bridge this gap an efficient scheduling heuristic for conditional behaviors is presented. Our heuristic and the techniques it utilizes are based on a unifying design representation appropriate for both types of behavioral descriptions, enabling the proposed heuristic to exploit under the same framework several well-established techniques (chaining, multicycling) as well as conditional resource sharing and speculative execution which are essential in efficiently scheduling conditional behaviors. Preliminary experiments confirm the effectiveness of our approach and prompted the development of the CODESIS HLS tool for further experimentation.

Spreading sequences for uplink and downlink MC-CDMA systems: PAPR and MAI minimization

Abstract: This paper deals with spreading sequences selection for downlink and uplink Multi-Carrier Code Division Multiple Access (MC-CDMA) systems with the aim of minimizing the dynamic range of the transmitted multicarrier signal envelope and the multiple access interference. The crest factor of orthogonal and non-orthogonal sequences are compared analytically and by simulation for downlink and uplink phase shift keying MC-CDMA transmissions. Then, in order to minimize the multiple access interference produced by frequency selective channels, an optimized spreading sequence allocation procedure is presented. Finally, a selection of the spreading codes which jointly reduces the multiple access interference and the crest factor is proposed for downlink MC-CDMA systems.

Advanced wide cell pitch CSTBTs having light punch-through (LPT) structures

Abstract: In order to improve the total performance of nonpunch-through (NPT) type trench IGBT for the 1200/spl sim/1700 V region, a triple combination of concepts is adopted: "wide cell pitch" and "carrier stored trench-gate bipolar transistor (CSTBT)" for the emitter side, and "light punch-through (LPT)" structure for the collector side. The wide cell pitch LPT-CSTBT demonstrates lower on-state voltage, lower switching loss, lower junction leakage current than that of conventional NPT trench IGBT, and relatively large short circuit capability. In addition, our device shows excellent gate dielectric reliability by utilizing CVD gate oxide film. The LPT-CSTBT with CVD gate dielectric is a promising candidate for high voltage power devices, because its performance is approaches that of punch-through (PT) trench IGBTs.

Development of railway static power conditioner used at substation for Shinkansen

Abstract: High-speed AC electric railways, such as Shinkansen, require large single-phase AC electric power. So, if the short circuit capacity of the power system is not large enough, therefore, railway operation causes large voltage unbalance at the three-phase side. In this paper, a railway static power conditioner (RPC), a new system for reducing voltage unbalance and fluctuation, is described. To reduce voltage unbalance and fluctuation, the RPC balances effective power of different phase and compensates reactive power and harmonics. It enables operation of high-speed AC electrified railways even if the short circuit capacity of the power system is rather small.

Enhancement of spectral separation performance for ASTER/SWIR

Abstract: The mechanism of the crosstalk phenomena in the ASTER/SWIR subsystem, which has six bands in the wavelength of 1.6 - 2.43 micrometers region, is investigated. It is found that the incident light to a detector array of the band 4 of the SWIR subsystem is reflected at an electrical wiring at the focal plane. It is transported to detectors of other bands by multiple reflections through the bandpass filter in front of detectors. By analyzing SWIR images around islands and peninsulas, crosstalk components in images are estimated. For this purpose, the crosstalk correction software is developed. Parameters of the crosstalk phenomena, i.e., the amount of stray light and the influential area of stray light, are determined by image analysis. It is found that the spectral separation performance of the SWIR subsystem is enhanced using the correction software in this study, which leads to more accurate spectral studies of SWIR images and is promising in exploiting natural resources.

Performance Analysis and Parallel Implementation of Dedicated Hash Functions

Abstract: This paper shows an extensive software performance analysis of dedicated hash functions, particularly concentrating on Pentium III, which is a current dominant processor. The targeted hash functions are MD5, RIPEMD-128-160, SHA-1 -256 -512 and Whirlpool, which fully cover currently used and future promising hashing algorithms. We try to optimize hashing speed not only by carefully arranging pipeline scheduling but also by processing two or even three message blocks in parallel using MMX registers for 32-bit oriented hash functions. Moreover we thoroughly utilize 64-bit MMX instructions for maximizing performance of 64-bit oriented hash functions, SHA-512 and Whirlpool. To our best knowledge, this paper gives the first detailed measured performance analysis of SHA-256, SHA-512 and Whirlpool.

One-chip microcomputer with analog-to-digital converter

Abstract: An input circuit of a one-chip microcomputer is connected to an external switching circuit. When an analog input signal of a significant level generated in the external switching circuit is received at an analog input terminal of the input circuit, an A/D conversion start request signal is generated in an A/D conversion start request generating circuit and is sent to an A/D converter. The operation of the A/D converter is started in response to the A/D conversion start request signal, the analog input signal received at the analog input terminal is converted into digital data, and an A/D conversion finish signal is sent from the A/D converter to a CPU of the one-chip microcomputer. The operation of the CPU is started in response to the A/D conversion finish signal, and the digital data is readout to the CPU. Therefore, the A/D converter, the CPU or a clock is not operated to wait for an analog input signal generated in the external switching circuit, but the A/D converter is operated for the A/D conversion, and the CPU is operated to read out the digital data. Accordingly, an electric power consumed in the A/D converter, the CPU and the clock can be reduced.

Steering control device

Abstract: A steering control device is realized which is capable of handling a variety of torque sensors through the same signal processing circuit, and in which a cost increase is suppressed while taking sufficient failsafe measures, having a torque sensor for detecting a signal corresponding to a steering torque in a steering system; a first microcontroller for outputting a steering torque signal equivalent to the steering torque; a second microcontroller for controlling an actuator based on the steering torque signal outputted; actuator driving means for driving the actuator controlling the steering system; and storage means in which a steering torque neutral point compensation data is stored in advance; wherein the first microcontroller compensates a neutral point of the steering torque signal based on the neutral point compensation data stored in the storage means

"Circular type" quantum key distribution

Abstract: A "circular type" interferometric system for quantum key distribution is proposed. The system, which adopts a Sagnac loop, is highly stable and simple. The stability derives from its self-alignment and compensation for birefringence and the system's simplicity allows it to achieve an extremely fast bit rate. Moreover, it is easily applicable to multiparty setup. Key creation with 0.1 photon per pulse at a rate of 1.2 kHz with a 5.4% quantum bit-error rate over a 200-m fiber was realized.

Mode locking in Fabry-Perot semiconductor lasers

Abstract: Passive mode-locking (ML) operation in semiconductor quantum-well (QW) lasers with Fabry-Perot (FP) cavities is investigated theoretically and experimentally. Structural and operational conditions for a semiconductor QW laser to exhibit ``amplitude modulation (AM)'' or ``frequency modulation'' ML operations are investigated by numerical analysis based on a semiclassical laser model. It is shown experimentally that clear AM ML pulses self-build and persist under continuous current injection in ${\mathrm{In}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}\mathrm{As}/{\mathrm{In}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}{\mathrm{As}}_{y}{\mathrm{P}}_{1\ensuremath{-}y}/\mathrm{InP}$-based FP QW lasers with cavity lengths of $300\ensuremath{-}600 \ensuremath{\mu}\mathrm{m}.$ The observed ML features are explained in terms of the laser model.

Input channel switching control device for display monitor and method of controlling input channel switching of display monitor

Abstract: Discriminator receiving a DDC transmission request from an external computer through a DDC control, judges whether a video signal inputted from the computer is a signal of analog specification or digital specification from an analog channel input detection signal from an analog synchronizing signal detector. On the basis of the judgment result, the discriminator controls the DDC control, input channel switch and OSD switch to switch EDID data, an input channel and OSD into ones supporting the specification of the video signal, respectively. In a display monitor having a DDC function which includes a DVI-I connector, with the above constitution, a correct setting of the input channel, EDID data and the like is automatically made in accordance with the specification of the input signal.

Performance analysis and parallel implementation of dedicated hash functions

Abstract: This paper shows an extensive software performance analysis of dedicated hash functions, particularly concentrating on Pentium III, which is a current dominant processor. The targeted hash functions are MD5, RIPEMD-128 -160, SHA-1 -256 -512 and Whirlpool, which fully cover currently used and future promising hashing algorithms. We try to optimize hashing speed not only by carefully arranging pipeline scheduling but also by processing two or even three message blocks in parallel using MMX registers for 32-bit oriented hash functions. Moreover we thoroughly utilize 64-bit MMX instructions for maximizing performance of 64-bit oriented hash functions, SHA-512 and Whirlpool. To our best knowledge, this paper gives the first detailed measured performance analysis of SHA-256, SHA-512 and Whirlpool.

Permanent magnet dynamo electric machine, and permanent magnet synchronous generator for wind power generation

Abstract: A dynamo electric machine includes a rotor having magnetic poles with permanent magnets and a stator having armature windings concentratedly wound around teeth. When the number of pole pairs of the magnetic poles of the rotor is P, diameter of the rotor is D (meters), and a spatial harmonic order of a predetermined harmonic component of an armature magnetomotive force of the rotor is N ((N=P to the 1.5th power)×(N to the minus 4-th power)×(the square of P)×D<0.6 (in meters).

Method and apparatus for detecting data sequences

Abstract: A method of detecting a predetermined complex data sequence in a received signal, representing for example a broadcast burst preamble in a wireless LAN transmission, involves (a) performing an auto-correlation on the data extracted from the received signal to provide an auto-correlation output, (b) combining the auto-correlation output with a delayed version of the auto-correlation output to produce a combined output and (c) providing a signal representing the predetermined data sequence if the combined output meets a predetermined condition, preferably also taking into account the phases of the auto-correlation output.

The maximum operating region in SiGe HBTs for RF power amplifiers

Abstract: Microwave waveforms of SiGe HBTs have been directly measured. The maximum operating region has been experimentally investigated by sweeping the load lines and power of the input signal. The device is found to operate beyond the conventional BVceo, while GaAs HBTs cannot survive at that voltage. The conventional BVceo is found to limit the average Vc of the maximum load lines, but has no influence on the peak voltage. Another BVceo measured with a voltage generator is proposed to represent the avalanche breakdown instead of the conventional one.

Thin film magnetic memory device provided with a dummy cell for data read reference

Abstract: Normal memory cells and dummy cells are arranged continuously in a memory array. In a data read operation, first and second data lines are connected to the selected memory cell and the dummy cell, respectively, and are supplied with operation currents of a differential amplifier. An offset corresponding to a voltage difference between first and second offset control voltages applied from voltage generating circuits are provided between passing currents of the first and second data lines, and a reference current passing through the dummy cell is set to a level intermediate between two kinds of levels corresponding to storage data of a data read current passing through the selected memory cell.