• ETRI Journal
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• 제29권1호
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• pp.70-78
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• 2007

A new low-voltage CMOS interface circuit with digital output for piezo-resistive transducer is proposed. An input current sensing configuration is used to detect change in piezo-resistance due to applied pressure and to allow low-voltage circuit operation. A simple 1-bit first-order delta-sigma modulator is used to produce an output digital bitstream. The proposed interface circuit is realized in a 0.35 ${\mu}m$ CMOS technology and draws less than 200 ${\mu}A$ from a single 1.5 V power supply voltage. Simulation results show that the circuit can achieve an equivalent output resolution of 9.67 bits with less than 0.23% non-linearity error.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.772-775
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• 2004

Generally, arterial pulse waves are measured at the radial arterial of wrist or carotid arterial of neck using a sensor such as pressure sensor, piezoelectric sensor or optic sensor. But in this paper, arterial pulse wave is measured at the temple using PZT piezo sensor which is attached on the temple in form of a hair-band. Arterial Pulse waves are generally measured when a reagent is in a static state. But in this paper, we implemented the arterial pulse wave measurement system, as a previous stage of the arterial pulse wave measurement system for running at outdoors or on a running machine, that measures arterial pulse waves at the temple, which is the least moving part when running. Thorough the continuous study, if the motion artifact when running is possible to be removed, the system will be able to perform monitoring of running men's states and especially emergency signals such as serious pulse waves of an/old and feeble persons and handicapped persons.

• 한국기계가공학회지
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• 제10권5호
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• pp.20-25
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• 2011

In this paper, we reviewed the spindle system's motor and bearing and its mode safety for optimal design of a high speed spindle system that exceeds DmN value of 1,500,000. We could verify that it has a separation margin during critical speed by performing critical speed analysis. Also, we have selected an optimal sensoring installation location and actually manufactured & installed the sensor by identifying the stress concentration position in the axial load through finite element analysis to install the built-in piezo electric type load sensor to the spindle housing that can measure and monitor the machining load during high speed rotation of the spindle. Reproducibility is also verified by calibrating the error through the sensor's sensitivity adjustment after comparing the output between the plate dynamoneters and the load sensor to confirm the reproducibility of the load sensor.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.434-439
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• 1997

This paper presents the active control of a flexible plate vibration. The plate was excited by white noise point force and the control was performed by one or two piezo ceramic actuator bonded to the surface of the plate. An adaptive controller based on filtered-x or multiple filtered-x LMS algorithm was used and the controller was defined by minimizing the square of the response of error sensor. In the experiment, PZT sensor was used as an error sensor while white noise was applied as a disturbance. In the case of multiple channel control, more than 22 dB of vibration reduction was achieved. Results indicate that the vibration of a flexible plate could be controlled effectively when the piezo ceramic actuator was used with multiple filtered-x LMS algorithm.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.3114-3120
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• 2023

A high-accuracy magnetic field measurement device based on a cyclotron is being developed for accelerator mass spectrometry (AMS). In this study, a magnetic field measurement device consisting of a Hall probe sensor, piezo-motor, and step motor was developed to measure the magnetic field of the AMS cyclotron magnet. The Hall probe sensor was calibrated to achieve positional accuracy by using polar coordinates. The measurement results between the ratchet gear and piezo-motor, which are the instruments used for driving the measurement device, were analyzed. The measurement result of the device with a piezo-motor exhibits a difference of 5 Gauss (0.04%) as compared with the simulation result.

• 한국산학기술학회논문지
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• 제14권7호
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• pp.3191-3196
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• 2013

초음파 센서는 거리를 측정하는 센서이다. 초음파 센서의 피에조 세라믹과 매칭레이어 접착기술이 가장 핵심이 되는 기술이다. 본 논문에서는 초음파를 공기 중으로 발진해 주는 매칭레이어에 대한 관계의 연구와 함께 피에조 세라믹과 매칭레이어를 접착한 경우 변화될 수 있는 결과를 추출하여 제 2의 사용가능 주파수를 발견하는 것이 목적이다. 또한 실제 압전소자인 피에조 세라믹과 케미컬우드인 매칭레이어를 사용하여 실험하였다. 피에조 세라믹의 OD는 ${\Phi}50{\times}3T$로 설계 되었으며 매칭레이어 OD는 ${\lambda}=1/4$인 ${\Phi}62{\times}12t$로 설계하였다. 가장 최적의 공진 주파수는 53 Khz에서 음향 임피던스 값을 나타냈다. 실험결과, 유연성을 가진 접착제 보다 고체에 가까운 접착제를 사용할 경우에 많은 사용가능 주파수를 생성할 수 있는 결과를 얻을 수 있다.

• Design & Manufacturing
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• 제15권4호
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• pp.51-56
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• 2021

Piercing is the process of shearing a circular hole in sheet metal, whose high shear force makes it difficult to secure the durability of tools. In addition, uneven clearance between tools due to poor alignment of the piercing punch causes accelerated die wear and breakage of the tool. This study reviewed the feasibility of in-situ determining alignment failure during the piercing process by analyzing the signal deviation of a bolt-type piezo sensor installed inside the tool whose alignment level was controlled. Finite element analysis was performed to select the optimal sensor location on the piercing tool for sensitive detection of process signals. A well-aligned piercing process results in uniform deformation in the circumferential direction, and shearing is completed at a stroke similar to the sheet thickness. Afterward, a sharp decrease in shear load is observed. The misaligned piecing punch leads to a gradual decrease in the load after the maximum shear load. This gradual decrease is due to the progressive shear deformation that proceeds in the circumferential direction after the initial crack occurs at the narrow clearance site. Therefore, analyzing the stroke at which the maximum shear load occurs and the load reduction rate after that could detect the misalignment of the piercing punch in real-time.

• 센서학회지
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• 제25권1호
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• pp.35-40
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• 2016

Pulse diagnosis is one of the representative diagnostic methods in Oriental medicine. In this study, a pulse pressure sensor array coated with silicone, which includes 6 piezo-resistive sensors and 1 thermistor, is fabricated for pulse measurement. It is necessary to coat the pulse sensor array with silicone to avoid the fracture or damage of pressure sensors when the sensor is in contact with the skin and a constant pressure is applied. However, the silicone coating on the pulse sensor array can cause signal interference among the sensors in the pulse sensor array. The interference number (IN), a calculation for expressing the degree of interference among channels, is changed according to the silicone thickness on the pulse sensor array. The IN is increased by a thick silicone coating, but the fabrication error, an important index for the mass production of the sensor array, is reduced by the thickness of the silicone coating. We propose that the thickness of the silicone on the pulse sensor array is an important consideration for the performance of the fabricated sensor and manufacturing repeatability.

• 소성∙가공
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• 제31권1호
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• pp.5-10
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• 2022

In multi-stage cold forging process, to enhance the productivity and product quality, in-site process monitoring technique by implanting sensors such as piezo-sensor and acoustic emission sensor has been continuously studied. For accurate analysis of the process, the selection of appropriate sensors and implantation positions are very important. Until now, in a multi-state forging machine, wedge parts located at the end of punch-set are used but it is difficult to analyze minute changes in die block-set. In this study, we also implanted sensors to the die part (die spacer) and compared signals from both sensors and found that sensing signals from die part showed enhanced process monitoring results.

• 대한수학회지
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• 제32권4호
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• pp.869-876
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• 1995

Piezo devices such as piezoceramic patches knwon as collocated rate sensor and actuators are commonly used in control of flexible structure (see, e.g., [1]) and noise reduction. Recently, Ito and Kang ([4]) developed a nonlinear feedback control synthesis for regulating fluid flow using these devices.