Shijie Guo

RIKEN, Вако, Saitama, Japan

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Publications (12)2.25 Total impact

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    Kazuya Matsuo · Toshiharu Mukai · Yo Kato · Shijie Guo
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    ABSTRACT: We describe a measurement method of respiration and heartbeat using a Smart Rubber sensor, a rubber-based flexible tactile sensor sheet that we developed. This method is useful for unconstrained recording of a person sleeping soundly, sleeping lightly, lying down, sitting on a bed, and so on. Our goal is to monitor those who require nursing care. The proposed method measures respiration and heartbeat as follows. First, we measure body pressure by using the Smart Rubber sensor placed on a bed. Then, the method applies a frequency analysis to the time series data of body pressure. Finally, respiration and heartbeat are obtained by extracting suitable frequency bands. In the experiments, we show that respiration and heartbeat are successfully measured. Moreover, we report that the stability of the measurement method of respiration and heartbeat.
    Preview · Article · Jan 2015
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    ABSTRACT: Sleep monitoring systems that can be used in daily life for the assessment of personal health and early detection of diseases are needed. To this end, we are developing a system for unconstrained measurement of the lying posture, respiration and heartbeat of a person on a soft rubber-based tactile sensor sheet. The respiration and heartbeat signals can be detected from only particular locations on the tactile sensor, and the locations depend on the lying location and posture of the measured person. In this paper, we describe how to determine the measurement locations on the sensor. We also report a realtime program that detects the respiration rate and the heart rate by using this method.
    No preview · Article · Aug 2014
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    ABSTRACT: Traditional capacitive tactile sensor sheets usually have a three-layered structure, with a dielectric layer sandwiched by two electrode layers. Each electrode layer has a number of parallel ribbon-like electrodes. The electrodes on the two electrode layers are oriented orthogonally and each crossing point of the two perpendicular electrode arrays makes up a capacitive sensor cell on the sheet. It is well known that compatibility between measuring precision and resolution is difficult, since decreasing the width of the electrodes is required to obtain a high resolution, however, this may lead to reduction of the area of the sensor cells, and as a result, lead to a low Signal/Noise (S/N) ratio. To overcome this problem, a new multilayered structure and related calculation procedure are proposed. This new structure stacks two or more sensor sheets with shifts in position. Both a high precision and a high resolution can be obtained by combining the signals of the stacked sensor sheets. Trial production was made and the effect was confirmed.
    Preview · Article · Feb 2014 · Sensors
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    ABSTRACT: Sleep monitoring provides useful information for keeping a good health condition and detecting diseases. The monitoring system should not interfere with natural sleep, and be an existence that is almost unnoticed by the person being measured, to be used in daily life. We propose a method for unconstrained measurement of the lying posture, respiration and heartbeat of a person on a rubber-based tactile sensor sheet. The tactile sensor is soft, flexible, and thin, and is not uncomfortable for the person lying on it. To extract faint heartbeat signals from pressure detected by the tactile sensor, improvement of the S/N ratio by averaging oversampled data is needed. This process takes some time, and can be conducted at only a limited number of locations on the tactile sensor. The suitable locations for the heartbeat detection depend on not only the location but also the lying posture of the person on the sensor. In the proposed method, the lying location and posture are detected using a pattern recognition technique applied on pressure pattern obtained by the tactile sensor. The parameters in the pattern recognition are adjusted by using machine learning based on pressure pattern samples. In this paper, we describe the method for unconstrained measurement and report the experimental results.
    No preview · Article · Jan 2014
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    ABSTRACT: Traditional capacitance sensor sheets usually have a three-layered structure, with a dielectric layer sandwiched by two electrode layers. Each electrode layer has a number of parallel ribbon-like electrodes. The electrodes on the two electrode layers are oriented orthogonally and each crossing area of two crossing electrodes makes up a capacitance sensor cell on the sheet. It is well known that compatibility between measuring precision and resolution is difficult since decreasing the width of the electrodes is inevitable to obtain a high resolution, however, this may lead to reduction of the area of the sensor cells, and as a result, lead to a low S/N ratio. To overcome this problem, a new multilayered structure and related signal processing approach were proposed. This new structure stacks two or more sensor sheets with shifts in position. Both a high precision and a high resolution can be obtained by combining the signals of the stacked sensor sheets. Trial production was made and the effect was confirmed.
    No preview · Article · Jan 2013
  • Yo Kato · Shijie Guo

    No preview · Article · Jan 2013
  • Source
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    ABSTRACT: A novel pneumatic artificial muscle actuator is presented which is based on the design of a conventional curved type pneumatic bellows actuator. By inhibiting the extension of one side with fiber reinforcement, bending motion can be induced when air is supplied to the internal bladder. In this study, we developed a new actuator by replacing the fiber reinforcement with a Shape-Memory Polymer (SMP). The SMP can be deformed above its glass transition temperature (T g) and maintains a rigid shape after it is cooled below T g. When next heated above T g, it returns to its initial shape. When only part of our actuator is warmed above T g, only that portion of the SMP is soft and can actuate. Therefore, the direction of the motion can be controlled by heating. Moreover, our actuator can be deformed by an external force above T g and fixed by cooling it below T g.
    Full-text · Article · Jun 2012
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    ABSTRACT: With a record-low birthrate and a rapidly-growing elderly population, Japan faces a severe demographic challenge, compounded by a chronic lack of nursing care staff. Among nursing care tasks, patient transfer is one of the most physically strenuous tasks. To free caregivers from such heavy physical work and to compensate for the lack of nursing care staff, we have developed two prototype robots, RIBA and RIBA-II, which were designed to come in direct contact with patients and conduct transfer tasks such as lifting and moving a patient from a bed or the floor to a wheelchair and back. This paper, focusing on RIBA-II, describes the motion design, handling method, safety measures, as well as the verification experiment conducted on healthy subjects. RIBA-II, who's whole body including the joints is covered with soft materials to realize a safe and easy contact with humans, has the ability to lift up a human up to 80kg with a certain safety factor from the floor and transfer him/her to a normal wheelchair with armrests. The robot is not an autonomous one but a robot operated by a caregiver to ensure safety. When conducting a transfer task, the caregiver handles the robot by stroking the rubber tactile sensors installed on the robot arms and, at the same time, confirms safety. The purpose of the robot is not only relieving caregivers from heavy physical works but also to replace the transfer task conducted by two caregivers by one robot and one caregiver. The feasibility has been demonstrated by the verification experiment as described in this paper.
    No preview · Article · Jan 2012
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    ABSTRACT: In aging societies, there is a strong demand for robotics to tackle problems resulting from the aging population. We have developed a prototype nursing-care assistant robot, RIBA, which was designed to come in direct contact with patients and conduct physically challenging tasks. RIBA interacts with its object, typically a human, through multiple and distributed contact regions on its arms and body. To obtain information on such whole-body contact, RIBA has tactile sensors on a wide area of its arms. The regions where hard contact with the manipulated person may occur have almost flat surfaces, leading to surface contact involving a finite area, in order to reduce contact pressure and not to cause the person's pain. When controlling the position and orientation of the person, the relative positions and orientations of the distributed contacting surfaces should be preserved as far as possible to maintain stable contact and not to graze the person's skin. Preserving the force and the pressure pattern of each contact region using tactile feedback is also important to provide stable and comfortable human-robot physical interaction. In this paper, we propose a whole-body contact manipulation method using tactile information to meet these requirements.
    Preview · Conference Paper · Sep 2011
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    ABSTRACT: In aging societies, there is a strong demand for robotics to tackle problems resulting from the aging population. Patient transfer, such as lifting and moving a bedridden patient from a bed to a wheelchair and back, is one of the most physically challenging tasks in nursing care. We have developed a prototype nursing-care assistant robot, RIBA, that can conduct patient transfer using human-type arms. The basic robot motion trajectories are created by interpolating several postures designated in advance. To accomplish more flexible and suitable motion, adjustment using sensor information is necessary, because the patient's posture and positions in contact with the robot may differ slightly in each trial. In this paper, we propose a motion adjustment method in patient lifting using tactile sensors mounted on the robot arms. The results of experiments using a lifesize dummy are also presented.
    No preview · Conference Paper · Jun 2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: In aging societies, there is a strong demand for robotics to tackle problems resulting from the aging population. We have developed a prototype nursing-care assistant robot, RIBA, which was designed to come in direct contact with patients and conduct physically challenging tasks. RIBA interacts with its object, typically a human, through multiple and distributed contact regions on its arms and body. To obtain information on such whole-body contact, RIBA has tactile sensors on a wide area of its arms. The regions where hard contact with the manipulated person may occur have almost flat surfaces, leading to surface contact involving a finite area, in order to reduce contact pressure and not to cause the person's pain. When controlling the position and orientation of the person, the relative positions and orientations of the distributed contacting surfaces should be preserved as far as possible to maintain stable contact and not to graze the person's skin. Preserving the force and the pressure pattern of each contact region using tactile feedback is also important to provide stable and comfortable human-robot physical interaction. In this paper, we propose a whole-body contact manipulation method using tactile information to meet these requirements. Results of basic experiments are also shown.
    No preview · Article · Jan 2011
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    ABSTRACT: Above their glass transition temperature, shape-memory polymers (SMPs) can be deformed by applying a small load. They maintain their shape after they have been cooled below the glass transition temperature, and then return to a predefined shape when heated above the glass transition temperature. The reversible change in the elastic modulus between the glassy and rubbery states of SMPs can be of the order of 100 to 1000 times. Exploiting these characteristics, this study seeks to evaluate the fundamental performance of a position-keeping module that uses an SMP. When this position-keeping module is warmed above its glass transition temperature, the SMP deforms and the module deforms on applying a small load. After the position-keeping module reaches a desired length, it is cooled to below the glass transition temperature and the SMP can be fixed in a rigid state without supplying electric power. The experimental results of a preliminary proof-of-concept investigation conducted on SMP tubes confirm the feasibility of using an SMP to fabricate a reliable, light and low-cost position-keeping module for a robot arm.
    Full-text · Article · Jan 2010