Details of a Researcher - Nishi, Hiroaki

Papers - Nishi, Hiroaki

Division display 241 - 260 of about 314 ／ All the affair displays >>

武井貴義, 下野誠通, 久保亮吾, 西宏章, 大西公平

電気学会産業応用部門誌 (The Institute of Electrical Engineers of Japan) 128-D ( 6 ) 767 - 774 2008.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 0913-6339

In this paper, the estimation method of only gravity and the compensation method of only the disturbance caused by gravity are proposed. The proposed method is able to estimate gravity, even when the system has the unknown posture. The proposed method is based on the concept of "environment quarrier". Then, environment quarry is expanded to multilateral control. In this paper, two dummy robots that are the environment quarrier are implemented besides master-slave system, in order to abstract only gravity disturbance. The proposed method is adaptable, even when mass of master system differs from one of slave system. To verify the viability of the proposed method, experimental results are shown. © 2008 The Institute of Electrical Engineers of Japan.

Access to Document (DOI)

Development of multi-degree-of-freedom bilateral forceps robot system using FPGA

Ena Ishii, Seiichiro Katsura, Hiroaki Nishi and Kouhei Ohnishi

Electronics and Communications in Japan (WILEY) 91 ( 6 ) 23 - 33 2008.06

Research paper (scientific journal), Joint Work, Accepted, ISSN 1942-9533

Fast growing use of minimally invasive endoscopic surgeries called for development of robots assisting in such procedures. However, existing surgical robots cannot transmit tactile sensation to the operator. To overcome this shortcoming, a bilateral teleoperation method was developed making it possible to accurately convey tactile sensation in single-degree-of-freedom forceps robots. This paper deals with the development of a multi-degree-of-freedom bilateral forceps robot system for surgical procedures which can adapt to actual conditions of the surgery.Bilateral teleoperation of multi-degree-of-freedom robots requires exchange of environmental information between master and slave devices in common coordinates. In this study we adopted mode coordinates which are better related to the motion of the robot. We also proposed a method to decouple the mechanical interference in mode coordinates. An FPGA-based controller introduced in this study makes it possible to reduce data processing time and to use hardware-based real-time control. As a result, multi-degree-of-freedom force feedback is attained.The experimental results show the viability of the proposed method. (C) 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(6): 23-33, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10118

Access to Document (DOI)

Semantic router using data stream to enrich services

Koichi Inoue, Dai Akashi, Michihiro Koibuchi, Hideyuki Kawashima, Hiroaki Nishi

International Conference on Future Internet Technologies (CFI08) 20 - 23 2008.06

Accepted

Realization of acceleration control using multirate sampling method

Mariko Mizuochi, Toshiaki Tsuji, Hiroaki Nishi, and Kouhei Ohnishi

Electrical Engineering in Japan (WILEY) 192 ( 4 ) 72 - 81 2008.03

Research paper (scientific journal), ISSN 0424-7760

This paper focuses on the realization of high-performance motion control based on acceleration control. The characteristics of acceleration control are investigated and the relationship between the performance and sampling frequency of the system is discussed. This paper then describes that a higher sampling frequency is required for acquisition of output information than for updating the input value. Based on this idea, a new multirate sampling method for an acceleration control system is proposed. A disturbance observer for the multirate system is designed by adopting a new definition of disturbance torque. A bilateral system is introduced as a preeminent example of a system that requires robust acceleration control. Both simulations and experiments are performed on the system, and the validity of the proposition is verified by the results. © 2007 Wiley Periodicals, Inc.

Access to Document (DOI)

An approach to acceleration estimation using FPGA

Hiroyuki Tanaka, Hiroaki Nishi, Kouhei Ohnishi

IEEE International Symposium on Industrial Electronics (IEEE) 1959 - 1964 2008

Accepted

the field of motion control, robustness is an important issue to accomplish desired motion of robots. To achieve robust motion control, acceleration control has been studied. In the acceleration control, disturbance observer is used to estimate and compensate disturbance force applied to an actuator. In the disturbance observer, the disturbance is estimated with calculating acceleration based on velocity/position information, and the estimated disturbance is obtained through a low-pass filter. To achieve accurate disturbance estimation, higher cut-off frequency of the low-pass filter and exact acceleration information are required. To set higher cut-off frequency of the low-pass filter, shortening sampling period is an effective method using FPGA as a motion control processor. However, short sampling period generally deteriorates the resolution of the velocity/acceleration information. This means that the estimated disturbance can include large error. In this paper, an acceleration estimation method is proposed to improve the resolution of acceleration in systems whose sampling period is very short. The validity of the proposed method is demonstrated by simulation and experimental results. © 2008 IEEE.

Access to Document (DOI)

Cooperative distributed demand control by environmental sensor network estimating the number of people by co<inf>2</inf> concentration

Tomokazu Tachikawa, Akihiro Oda, Toshihiko Handa, Junichi Ichimura, Yuji Watanabe, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) (IEEE) 336 - 341 2008

ISSN 1935-4576

KNIVES is a system for providing balanced power supply and effective demand control. This system controls the power of electric devices over the Internet, due to reduce total power consumption. For the control, KNIVES also considers indoor environmental affinity by using environmental sensors. In this paper, CO2 sensor is implemented on KNIVES terminal and it enables to measure CO2 concentration for assessing indoor vitiation. This paper verifies the effectiveness of this sensor by estimating the number of people. Also, the number of people is one of the parameter for effective control. Existing estimating method for counting the number of people, however, is difficult to install in a existing building. This paper describes the new estimating method for the number of people by CO2 concentration. As a result, this method can accomplish accurate measurement, and it can be applied to various applications for a future demand control. ©2008 IEEE.

Access to Document (DOI)

Haptic endoscopic surgery robot utilizing FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi, Toshikazu Kawai, Yasuhide Morikawa, Soji Ozawa, Toshiharu Furukawa

International Workshop on Advanced Motion Control, AMC (IEEE) 1 601 - 606 2008

Accepted

In late years, techniques and instruments for endoscopic surgery have been developed. The endoscopic surgery is a minimally invasive surgery, hence the Quality of Life (QOL) of patients can be improved. The endoscopic surgery still has, however, great difficulty for surgeons despite the development of the techniques and the instruments. To solve the problem, it has been studied to apply the technology of robotics to the endoscopic surgery. In this paper, a multi-degree of freedom haptic endoscopic surgery robot is developed aiming at the practical application of applying the robotics technology to the endoscopic surgery. The developed robot is a master-slave type robot, and a bilateral control system based on acceleration control is implemented. To achieve a short sampling period of the control calculation, FPGAs are utilized as processors. The validity of the developed robot is verified through some experimental results. © 2008 IEEE.

Access to Document (DOI)

Table-based scheduling method for distributed demand side management

Toshihiko Handa, Akihiro Oda, Tomokazu Tachikawa, Yuji Watanabe, Jun Ichi Ichimura, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) (IEEE) 2748 - 2753 2008

ISSN 1553-572X

Internet based demand and supply control system is expected as an effective solution for saving fossil fuels by controlling power consumption automatically with taking account of environmental information. KNIVES is one of this systems and it uses distributed and cooperative power control algorithm. In 2007, the latest prototype of KNIVES has been developed and be operated so as to evaluate in real environment. KNIVES aims to improve the total efficiency of energy utilization in general household. The distributed and cooperative control is considered to improve the advantages of demand control system even if the controlled building is a small-scale customer. In this paper, the table-based scheduling method adapted to the distribute DSM is introduced. Furthermore, the enhancement of this method in order to aware environmental amenity is also indicated. © 2008 IEEE.

Access to Document (DOI)

Structural health monitoring system considering fault-tolerance

Yoshinao Matsushiba, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) (IEEE) 330 - 335 2008

ISSN 1935-4576

Structural Health Monitoring (SHM) system uses a number of sensors for a precise prediction. This prediction enables to provide early indication of vulnerability of a structure and the timing of reinforcement in order to prevent future collapse. SHM systems are now widely spreading in infrastructures. However, conventional SHM systems did not take account of accidental collapse. There is a possibility that sensor node goes down or network goes offline. If sensor nodes are broken by damage, important data, stored in the nodes will have lost. To prevent the data loss, this paper proposes data-distributed fault-tolerant sensor network system for a SHM system. Proposed system consists of three functions, PING (Packet InterNet Groper) based network monitoring function (PNM), backup node selecting function (BNS) and socket communication function. Proposed system is implemented on PCs and practically evaluated in a laboratory environment on terminals of KNIVES, which is a test bed of sensor network system. As a result, Data sharing process on PC and KNIVES was confirmed and proposed method can provide a light-weight fault-tolerant system taking account of accidental collapse. ©2008 IEEE.

Access to Document (DOI)

Perfect Classified Channel retaining DC balance for high-throughput communication

Hiroki Matsuoka, Kouichi Inoue, Hiroaki Nishi

2008 International Symposium on Information Theory and its Applications, ISITA2008 (IEEE) 1273 - 1278 2008

Accepted

In this paper, a practical architecture of physical layer for preventing from a leak of information, named Perfect Classified Channel (PCC), is proposed. PCC is a hardware- based Layer-1 encryption system and it prevents leak of not only packet information but also existence of packet. PCC can be used as high-throughput communication path without using 8B/10B or 64B/66B coding algorithm in order to achieve DC balancing, by using AES circuit fully made of logic gates. PCC establishes Hop-by-Hop classified channel for data transmission between routers, switches, or nodes. This paper confirms the DC balancing ability of PCC and shows the detail of its hardware architecture.

Access to Document (DOI)

KNIVES: A distributed demand side management system - integration with ZigBee wireless sensor network and application -

Toshihiko Handa, Akihiro Oda, Tomokazu Tachikawa, Junichi Ichimura, Yuji Watanabe, Hiroaki Nishi

IEEE International Conference on Industrial Informatics (INDIN) (IEEE) 324 - 329 2008

ISSN 1935-4576

KNIVES is proposed as Internet based demand and supply control system and controls power by using distributed and cooperative power control algorithm. However, if KNIVES aims to maintain indoor environmental amenity, installed locations and the numbers of environmental sensors are critical issues. Wireless sensor network is useful to measure environmental data of various points where a wired sensor is not available or cost of wired installation is expensive, and makes it easy to install or to relocate the sensors. In this paper, we implement ZigBee wireless sensor network and make operational test to discuss about the application of demand control method by using wireless sensor network. Furthermore, we propose some demand control application with ZigBee, customized environment-based control and head-count-based control, to make DSM more efficient. ©2008 IEEE.

Access to Document (DOI)

Implementation of multirate acceleration control based bilateral control system including mode transformation on FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) (IEEE) 2465 - 2470 2008

Accepted, ISSN 1553-572X

FPGA has been focused on as a controller of robot systems. Haptic robot system based on bilateral control system is one of the significant applications using the FPGA. In this paper, the bilateral control system including mode transformation is implemented on the FPGA. The bilateral control system is based on acceleration control system. The mode transformation is a transformation between robot mode space and operational mode space. Furthermore, multirate sampling method is introduced to consider hardware limitation. Some experimental results are shown in order to verify the validity of the implementation. © 2008 IEEE.

Access to Document (DOI)

Martini: A Network Interface Controller Chip for High Performance Computing with Distributed PCs

Konosuke Watanabe, Tomohiro Otsuka, Junichiro Tsuchiya, Hiroaki Hiroaki, Junji Yamamoto, Noboru Tanabe, Tomohiro Kudoh, Hideharu Amano

IEEE Transactions on Parallel and Distributed Systems (IEEE Computer Society) 18 ( 9 ) 1282-1295 - 1295 2007.09

Research paper (scientific journal), Joint Work, Accepted, ISSN 1045-9219

In this paper, "Martini," a network interface controller chip for our original network called RHiNET is described. Martini is designed to provide high-bandwidth and low-latency communication with small overhead. To obtain high performance communication, protected user-level zero-copy RDMA communication functions are completely implemented by a hardwired logic. Also, to reduce the communication latency efficiently, we have proposed PIO-based communication mechanisms called "On-the-fly (OTF)" and have implemented them on Martini. The evaluation results show that Martini connected to a 64bit/66MHz PCI-bus achieves 470MByte/s maximum bidirectional bandwidth and 1.74 μsec minimum latency on host-to-host memory copying. © 2007 IEEE.

Access to Document (DOI)

Improvement of Performances in Bilateral Teleoperation by Using FPGA

Ena Ishii, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transactions on Industrial Electronics 54 ( 4 ) 1876-1884 2007.08

Research paper (scientific journal), Single Work, Accepted

Collision Avoidance Method of Humanoid Robot With Arm Force

Eijiro Ohashi, Takahiro Aiko, Toshiaki Tsuji, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transactions on Industrial Electronics (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC) 54 ( 3 ) 1632-1641 - 1641 2007.08

Research paper (scientific journal), Single Work, Accepted, ISSN 0278-0046

This paper describes a collision avoidance method for a biped robot with an upper body. We propose a method wherein the robot stops in front of an obstacle by generating arm force. When the robot detects the obstacle by the arm tip, it should stop short of the obstacle to avoid crash. Hence, we propose trajectory planning in consideration of the pushing force of the arm. The arm force is controlled to be generated as a function of the distance from the robot body to the obstacle. The closer the robot approaches the obstacle, the larger the arm force becomes. As a result, the robot can stop by utilizing the arm force. In case the obstacle is unmovable, the robot can stop by exerting arm force. If it is movable, the robot can continue walking by pushing it. In this paper, the linear inverted pendulum mode (LIPM) and the idea of orbital energy are introduced, and then, we extend LIPM and orbital energy in consideration of the dynamics of the arm force. The extended orbital energy is utilized to discriminate whether the robot can stop or not and to modify the trajectory of the robot to avoid collision. © 2007 IEEE.

Access to Document (DOI)

Improvement of Performances in Bilateral Teleoperation by Using FPGA

Ena Ishii, Hiroaki Nishi, Kouhei Ohnishi

IEEE Transactions on Industrial Electronics 54 ( 4 ) 1876-1884 2007.08

Research paper (scientific journal), Joint Work, Accepted

伝搬遅延を考慮したシステム結合の一表現法

名取賢治, 西宏章, 大西公平

電気学会論文誌D 産業応用部門誌 127 ( 6 ) 635-642 2007.06

Research paper (scientific journal), Single Work, Accepted

FPGAを用いた多自由度バイラテラル鉗子ロボットシステムの構築

石井恵那, 桂誠一郎, 西宏章, 大西公平

電気学会産業応用部門誌 (The Institute of Electrical Engineers of Japan) 127-D ( 5 ) 508-517 - 517 2007.05

Research paper (scientific journal), Single Work, Accepted, ISSN 0913-6339

In recent days, minimally invasive surgery by using endoscope has spread and robots that support endoscopic surgery are being focused on. However, existing surgery robots could not transmit information of tactile sensation to operators. To improve the safety of robotic surgery, it is required to transmit the tactile sensation to the operator. To attain that need, a teleoperation method called bilateral has developed and we have achieved to transmit keen tactile sensation with one degree-of-freedom forceps robots. In this paper, multi degrees-of-freedom bilateral forceps robot system will be developed to make surgery robot adaptable to actual situation of the surgery. In bilateral teleoperation of multi degrees-of-freedom robots, environmental information of master and slave should be exchanged in common coordinates. In this paper, mode coordinates is used as common coordinates. Mode coordinates are closely related to the motion of the robot. Method to decouple the mechanical interference on mode coordinate is proposed. The paper also proposes a controller implemented on FPGA to achieve short processing time and hard-realtime control. As a result, multi-degrees-of freedom force feedback is attained. The experimental results show the viability of the proposed method.

Access to Document (DOI)

An approach to velocity estimation using FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi

IECON Proceedings (Industrial Electronics Conference) (IEEE) 2349 - 2354 2007

Accepted, ISSN 1553-572X

FPGAs are focused on recently as motion control processors. Sampling periods become shorter by using FPGAs, and it is expected that improvement of the performance of the motion control system. However in M method, which is the most generally used velocity estimation method, velocity resolution becomes low due to the short sampling period. This leads to a limitation of the performance, especially in acceleration control using a disturbance observer which requires accurate velocity information. There are several velocity estimation methods to improve the resolution. These methods require a dividing operation. From point of view of resource sharing and resource utilization of FPGAs, implementing divider is not desired. In this paper, velocity estimation which does not require any divider is proposed to improve the velocity resolution in the short sampling period system. The validity of the proposed method is demonstrated by simulation, and the proposed method is implemented into position control system based on the acceleration control in experiments. ©2007 IEEE.

Access to Document (DOI)

Bilateral control in multi DOF haptic surgical robotic system utilizing FPGA

Hiroyuki Tanaka, Kouhei Ohnishi, Hiroaki Nishi, Toshikazu Kawai, Yasuhide Morikawa, Masaki Kitajima, Soji Ozawa, Toshiharu Furukawa

IEEE International Symposium on Industrial Electronics (IEEE) 3084 - 3089 2007

Accepted

Minimally invasive surgery is an important issue from the point of view of patients' Quality of Life (QoL). An endoscopic surgery is one of the minimally invasive surgeries. With the endoscopic surgery, pain could be less. This operation, however, has difficulty, and surgeons have to be well trained. To solve this problem, an endoscopic surgery system based on haptic teleoperation was proposed. The characteristic of the system is position and force information is transmitted bilaterally between master and slave robots. This means that a teleoperation with haptic information can be achieved, and surgeons can perform a telesurgery safely and smoothly. The system, however, does not have enough degrees of freedom for an actual operation. In this paper, a multi degrees of freedom endoscopic robotic system is proposed. This system has 6 degrees of freedom on each master and slave robot. A haptic control system implemented in the proposed system is based on acceleration control. Due to control in acceleration dimension, robust and ideal position and force control are able to be attained simultaneously. The control system requires a short sampling period for attainment of wide bandwidth to transmit keen force sensation. To ensure the short sampling period in a multi degrees of freedom system, this paper proposes the multi degrees of freedom tele-robotic system utilizing FPGA as a controller. Finally the validity of the proposed system is shown by experimental results. ©2007 IEEE.

Access to Document (DOI)

　 Previous page - Next page 　