Details of a Researcher - Takahashi, Hidetoshi

Papers - Takahashi, Hidetoshi

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A piezoelectric flow sensor for wake-up switch of wireless sensor network node

Y Tomimatsu, K Kuwana, T Kobayashi, T Itoh, R Maeda

2012 Second Workshop on Design, Control and Software Implementation for … 2012

A piezoelectric cantilever with Helmholtz resonator for a sound-triggered wake-up switch

Y Tomimatsu, H Takahashi, T Kobayashi, K Matsumoto, I Shimoyama, ...

Proceedings of PowerMEMS, 295-298 2012

Triaxial force sensor with strain concentration notch beam for measurement of insect flight force

K Azuma, H Takahashi, T Kan, K Matsumoto, I Shimoyama

2012 IEEE 25th International Conference on Micro Electro Mechanical Systems … (IEEE) 140 - 143 2012

ISSN 1084-6999

This paper reports on the triaxial force measurement during flapping flight of a fruit fly (Drosophila melanogaster). The total flight force was measured by a triaxial force sensor. The sensor consists of a cantilever probe, two sensing beams and four wiring beams. The total size of the sensor was 2 mm x 3 mm x 0.5 mm. A fruit fly was attached to the tip of the cantilever probe. The triaxial forces were measured when the fruit fly flapped. The measured force varied in synchronization with the flapping frequency of 240 Hz. The maximum forces in both lift and thrust directions were approximately 40 mu N.

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Shear force detector using piezo-resistive beams with sidewall-doping

H Takahashi, A Nakai, K Matsumoto, I Shimoyama

Micro Electro Mechanical Systems (MEMS), 2012 IEEE 25th International … (IEEE) 599 - 602 2012

ISSN 1084-6999

This paper reports on a shear force detector using piezo-resistive beams with sidewall doping embedded in elastic body. These beams are formed using a 20 mu m-thick device Si layer of an SOI (Silicon on Insulator) wafer. Shear force is measured by the resistance change due to the extension/compression of the sidewall. The size of the beams is 180 mu m x 15 mu m x 20 mu m (length x width x thickness). Using these shear force detectors, a triaxial tactile sensor can be fabricated.

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Measurement of the pressure distribution during the onset of slip

N Thanh-Vinh, H Takahashi, N Binh-Khiem, K Matsumoto, I Shimoyama

SENSORS, 2012 IEEE, 1-4 (IEEE) 966 - 969 2012

ISSN 1930-0395

We report on the direct measurement of the pressure distribution of the contact surface between an elastic block and a rigid plate during the onset of slip. The measurement was carried out by using an array of seven MEMS pressure sensors embedded inside the elastic block. The results showed that the external loading force in lateral direction caused the inhomogeneous change in pressure along the contact surface: the pressure in area close to the trailing edge decreased while that at area close to the leading edge increased. This result explains why the local slip always started to occur from the trailing edge where the pressure became small.

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Micro suction cup array for wet/dry adhesion

N Thanh-Vinh, H Takahashi, T Kan, K Noda, K Matsumoto, I Shimoyama

2011 IEEE 24th International Conference on Micro Electro Mechanical Systems … (IEEE) 284 - 287 2011

ISSN 1084-6999

We propose a micro suction cup array for adhesion to both dry and wet surfaces. We measured the peel-off forces of a PDMS micro suction cup array, a PDMS flat-tip micro structure array and a flat PDMS pad from both wet and dry glass surfaces. When the glass surface was wet, the peel-off forces of a PDMS flat-tip micro pattern and a flat PDMS pad decreased by more than 1.7 times and 7.0 times, respectively. On the other hand, peel-off forces of a PDMS micro suction cup array increased by over 1.1 times when the glass surface was wet. Also, in both wet and dry conditions, an array of PDMS micro suction cup adhered stronger to a glass surface than a PDMS flat-tip micro pattern and a flat PDMS pad. Furthermore, we demonstrated that the adhesion of a suction cup array can be enhanced by miniaturizing the size of the cups.

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3D airflow velocity vector sensor

NN Minh-Dung, H Takahashi, K Kuwana, T Takahata, K Matsumoto, ...

2011 IEEE 24th International Conference on Micro Electro Mechanical Systems … (IEEE) 513 - 516 2011

ISSN 1084-6999

In this paper, we propose a sensor for measuring the three-dimensional (3D) velocity vector of airflows. The sensor, which was a 10 mm spherical figure, had a laminated structure with three channels fabricated inside. The components of the airflow velocity vector were measured respectively by three piezo-resistive cantilevers fabricated in each of the three channels. Experiments with a wind tunnel demonstrated that our sensor can measure not only the velocity amplitude but the 3D velocity direction as well.

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Differential pressure distribution measurement of a free-flying butterfly wing

H Takahashi, K Matsumoto, I Shimoyama

Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS … 2022 - 2025 2011

This paper reports on differential pressure distribution measurement of a free-flying butterfly wing with a MEMS differential pressure sensor. A piezoresistive cantilever was used as a differential pressure sensor. The sensor chip was 1.0 mm 1.0 mm 0.3 mm in size and 0.7 mg in weight, respectively, so that it did not interfere with wing motion. Using a butterfly (Papilio protenor) with a sensor chip attached to the wing surface, the distribution of five points to the spanwise direction at the forewing and one point at the center of the hindwing was measured during takeoff. As a result, it was clarified that the maximum aerodynamic force generated on the wing was 3 times larger than the gravity acting on the body. © 2011 IEEE.

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Barometric pressure change measurement

N Minh-Dung, H Takahashi, K Matsumoto, I Shimoyama

Solid-State Sensors, Actuators and Microsystems Conference (TRANSDUCERS … 898 - 901 2011

In this paper, we report a high-sensitivity barometric pressure sensor for use in automotive navigation, personal mobile systems and environmental monitoring. The sensor consisted of an open cavity and a micro piezo-resistive cantilever, which is placed at the cavity's opening. In the proposed structure, the cavity did not need to be vacuum-sealed and the air-gap between the cantilever and its surrounding walls was micrometer order size. The cantilever was used to detect the time-variant interaction between barometric pressure and the pressure inside the cavity. Evaluation experiments demonstrate that the sensor is able to measure the barometric pressure change with high sensitivity, with expected resolution of 0.1 Pa. © 2011 IEEE.

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A gas sensor based on viscosity change of ionic liquid

K Ohsawa, H Takahashi, K Noda, T Kan, K Matsumoto, I Shimoyama

2011 IEEE 24th International Conference on Micro Electro Mechanical Systems … (IEEE) 525 - 528 2011

ISSN 1084-6999

We proposed a gas sensor based on viscosity change of ionic liquid. Our sensor consists of a piezoresistive cantilever immersed in an ionic liquid droplet. When the ionic liquid absorbs gas, the viscosity of the liquid decreases. Thus, the gas concentration is estimated by measuring the viscosity of the ionic liquid. We measured the viscosity change by monitoring the vibration amplitude of the immersed piezoresistive cantilever, which was vibrating in the ionic liquid by the magnetic field. The size of fabricated sensor chip was 1.5 mm x 1.5 mm x 0.3 mm. The cantilever and the volume of the ionic liquid droplet were 300 mu m x 200 mu m x 0.5 mu m and 0.4 mu l, respectively. We demonstrated that the vibration amplitude of the cantilever increased monotonically when acetone concentration rose from 0 to 15 mol%.

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Differential Pressure Measurement on Insect Modeled Ornithopter with MEMS Sensor in Free-flight

OHSAWA Kazuharu, AOYAMA Yuichiro, TAKAHASHI Hidetoshi, TANAKA Hiroto, IWASE Eiji, MATSUMOTO Kiyoshi, SHIMOYAMA Isao

Journal of the Robotics Society of Japan (The Robotics Society of Japan) 28 ( 9 ) 1131 - 1136 2010.11

Joint Work, ISSN 02891824

To achieve flight, an insect generates aerodynamic force by flapping its wings. However, this aerodynamic force acting on the wings has not been directly measured during free-flight. In this study, we fabricated an ornithopter modeled on a hawk moth, and attached a MEMS differential pressure sensor on its wing. Then, we measured differential pressure between upper and lower surfaces of the wing during free-flight. Reynolds number of the wing and wing load of the ornithopter were designed to be 4.2 × 103[–], and 7.5[N/m2], which were close to those of a hawk moth. The mass, wing length and flapping frequency were 6.8[g], 110[mm] and 13[Hz], respectively. The maximum differential pressures at the center of the wing were 39[Pa] and 18[Pa] during downstroke and upstroke, which were 5 and 2 times larger than the wing load. The differential pressure contributed vertical pressure of 38[Pa] during downstroke and horizontal pressure of 15[Pa] during upstroke. The time average of vertical differential pressure was 7.0[Pa], which was as large as the wing load of the ornithopter.

Differential pressure measurement on a flapping wing using a MEMS sensor

高橋英俊, 青山雄一郎, 大澤一治, 松本潔, 下山勲

可視化情報学会誌 30 ( Suppl.2 ) 207 - 208 2010.10

ISSN 0916-4731

Flight Mode Change with Wing Phase Relationship of Dragonfly-Type Flight(Fluids Engineering)

TAKAHASHI Hidetoshi, TANAKA Hiroto, MATSUMOTO Kiyoshi, SHIMOYAMA Isao

Transactions of the Japan Society of Mechanical Engineers. B (The Japan Society of Mechanical Engineers) 76 ( 768 ) 1199 - 1205 2010.08

Joint Work, ISSN 03875016

In this research, Dragonfly-type Ornithopers (DTOs) were developed to reveal the effect of the phase relationship between forewings and hindwings on flight performance. The DTO has high aspect four wings. The Reynolds number of the ornithopter is the same order as that of real dragonflies (10^3-10^4). The DTO's phase relationship ranges from 0° to 315° with 45° intervals. Flights of DTOs with various phase relationships were recorded with a high speed video camera, and their motions were analyzed. In the stable flight, the flight speed varied depending on the phase relationship. We also vis...

Measurement of differential pressure on a butterfly wing

H Takahashi, K Matsumoto, I Shimoyama

Micro Electro Mechanical Systems (MEMS), 2010 IEEE 23rd International … (IEEE) 63 - 66 2010

ISSN 1084-6999

This paper reports on direct measurement of differential pressure on a butterfly wing during free flight. Differential pressure was measured using a micro-fabricated sensor. A piezo-resistive cantilever was used as a differential pressure sensor. The sensor was 1.0 mm x 1.0 mm x 0.3 mm in size and 0.7 mg in weight so that it did not interfere with wing motion. By attaching the sensor to the center of a butterfly forewing with a flexible wiring, the differential pressure on the wing was measured during "no flight flapping" and "taking off".

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Differential pressure measurement using a free-flying insect-like ornithopter with an MEMS sensor

H Takahashi, Y Aoyama, K Ohsawa, H Tanaka, E Iwase, K Matsumoto, ...

Bioinspiration & biomimetics 5 (3), 036005 (IOP PUBLISHING LTD) 5 ( 3 ) 036005 2010

Research paper (scientific journal), Joint Work, Accepted, ISSN 1748-3182

This paper presents direct measurements of the aerodynamic forces on the wing of a free-flying, insect-like ornithopter that was modeled on a hawk moth (Manduca sexta). A micro differential pressure sensor was fabricated with micro electro mechanical systems (MEMS) technology and attached to the wing of the ornithopter. The sensor chip was less than 0.1% of the wing area. The mass of the sensor chip was 2.0 mg, which was less than 1% of the wing mass. Thus, the sensor was both small and light in comparison with the wing, resulting in a measurement system that had a minimal impact on the aerodynamics of the wing. With this sensor, the 'pressure coefficient' of the ornithopter wing was measured during both steady airflow and actual free flight. The maximum pressure coefficient observed for steady airflow conditions was 1.4 at an angle of attack of 30 degrees. In flapping flight, the coefficient was around 2.0 for angles of attack that ranged from 25 degrees to 40 degrees. Therefore, a larger aerodynamic force was generated during the downstroke in free flight compared to steady airflow conditions.

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Sound direction sensor with an acoustic channel

MD Nguyen, A Inaba, A Suzuki, H Takahashi, E Iwase, K Matsumoto, ...

2010 IEEE 23rd International Conference on Micro Electro Mechanical Systems … (IEEE) 655 - 658 2010

ISSN 1084-6999

This paper reports on a method for estimating direction of a sound with one directional acoustic sensor. Inspired by the two input structure of bushcricket ear, our sensor was designed to have an acoustic channel and a micro piezo-resistive cantilever. The radiated sound acts simultaneously on the external and on the inner surface of the cantilever. As the result, the directionality of our sensor varies with the frequency of incident sound. The sound direction was estimated by using directional responses of the sensor at multiple frequencies so that it does not require either angle scanning or microphone arrays. We demonstrated that this method enables the sound direction to be estimated with the average error of 4 degrees in laboratory experiments.

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Photo-response compensated piezoresistive cantilever for use in fluorescence microscopy

U Jung, K Kuwana, H Takahashi, T Kan, Y Takei, K Noda, E Iwase, ...

2010 IEEE 23rd International Conference on Micro Electro Mechanical Systems … (IEEE) 588 - 591 2010

ISSN 1084-6999

This paper presents the design, fabrication, and the characterization of a photo-response compensated piezoresistive cantilever. The application field of the cantilever is to measure cellular mechanical properties under fluorescence microscopy. Photo-response which is caused by an excitation light of a fluorescence microscope interferes with measurement. We proposed piezoresistive cantilevers consist of a force-sensing cantilever with a reference cantilever to cancel out the photo-response. We measured the photo-response of the fabricated device, by varying wavelength, light intensity and light incidence angle. The experimental results show that the photo-response was decreased by 87%. This verified that present device has effective photo-response compensation by using the reference cantilever.

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Flight mode change with wing phase relationship of dragonfly-type flight

H Takahashi, H Tanaka, K Matsumoto, I Shimoyama

Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of … 2010

平面型微小コイルを用いた局所高感度MRI

土肥徹次, 高橋英俊, 松本潔, 下山勲

生体医工学 (Japanese Society for Medical and Biological Engineering) 47 ( 16 ) 484 - 493 2009.12

Joint Work, Accepted, ISSN 1347-443X

In this study, we fabricated micro planar coils as a receiver for a high sensitive MRI (Magnetic Resonance Imaging). According to the calculation of the scale effect, the sensitivity of the coil increases with decrease of the diameter of the coil under the condition of fixed inductance. The micro planar coils of 5 and 20 mm in diameter were fabricated by using MEMS technology. The resistance and inductance of the 20 mm coil were 1.4 Ω and 1.15 μH at 8.5 MHz, respectively. Those of the 5 mm coil were 2.0 Ω and 1.05 μH, respectively. The MRI signal receivers were made by attaching the micro coils to the tip of acrylic pipes. The SNRs (Signal to Noise Ratio) of MR images of phantom were measured by the micro planar coils and the medical MRI coil of 200 mm in diameter. The SNRs of MR images taken by the micro planar coils were about 8 times as high as the MR image taken by the medical coil. MR images of an okra (Abelmoschus esculentus) were acquired by fabricated MRI signal receivers with the voxel size of 2.0 × 2.0 × 2.0 mm3 and 0.5 × 0.5 × 1.0 mm3. Since the sensitivity of micro planar coils was high, we were able to clearly observe inner structure of the okra.

Sensitivity enhancement by micro Helmholtz resonator for ultrasonic distance sensor

A Suzuki, H Takahashi, E Iwase, K Matsumoto, I Shimoyama

TRANSDUCERS 2009-2009 International Solid-State Sensors, Actuators and … 1557 - 1560 2009

This paper reports on a micro Helmholtz resonator (HR) enhancing the sensitivity of an ultrasonic distance sensor. Attaching an HR to the sensor that consists of a piezoresistive cantilever microphone makes its sensitivity against ultrasonic wave higher. A HR of 600 μm height demonstrated a 17.5 times larger maximum amplitude of the cantilever vibration against single frequency wave. We also evaluated the dependence of the sensitivity on frequency and acoustic pressure. Our sensor was able to detect the distance of 0.5-6.0 m with the maximum error of 2.0%. ©2009 IEEE.

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