• ETRI Journal
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• v.29 no.1
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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.

• Proceedings of the IEEK Conference
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• 2004.08c
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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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.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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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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• v.55 no.8
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3191-3196
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• 2013

Ultrasonic transducer is the sensor which is measuring distance. Piezo ceramic of ultrasonic sensor and adhesive technique of matching layer are the most core techniques. With the study of relation on matching layer which takes off the ultrasonic wave into the air, this paper aims to find the second useful frequency as the results which can be changed are extracted in case piezo ceramic and matching layer are bonded. And the experiment is done with piezo ceramic as real piezoelectric element and matching layer of chemical wood. OD of piezo ceramic has designed by ${\Phi}50{\times}3T$ and OD of matching layer is designed by ${\Phi}62{\times}12t$ with ${\lambda}=1/4$. Acoustic impedance is generated at the most optimum resonant frequency of 53 Khz. As experimental result, more available frequency can be generated by using the adhesive close to solid than the flexible one.

• Design & Manufacturing
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• v.15 no.4
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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.

• Journal of Sensor Science and Technology
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• v.25 no.1
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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.

• Transactions of Materials Processing
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• v.31 no.1
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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.

• Journal of the Korean Mathematical Society
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• v.32 no.4
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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.