• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.260-263
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• 2001

This paper is to develop the sensing system for opening-force measurement such as O-Ring muscular meridian. We designed to overcome the functional limit that the conventional force-sensor can measure just the closing-force. Therefore, the new sensor can meet a variety of application as well as O-Ring test. The structure of the new sensor is an actuator-type system using an electromagnet. That is made up of mechanical system, electromagnet, current transformer and computer interface circuit. Driving software and user interface program of the new sensor system also is explained in this paper.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.89-94
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• 2001

A cylindrical capacitance-type spindle displacement sensor was designed and tested in the hard turning as a way to develop a sensor that can estimate cutting forces without using a tool dynamometer. The displacement sensor was installed between the face of spindle cover and the chucking element, and measured pure radial motion of the spindle. Ceramic inserts and tool steel workpieceof 65 Rc were used during the hard turning tests. The signals from the sensor showed the same pattern of cutting force variations as those from the tool dynamometer. The research results showed that the developed sensor could be utilized as an effective and cheap on-line sensing device to estimate cutting forces.

• Journal of the Korean institute of surface engineering
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• v.39 no.2
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• pp.64-69
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• 2006

Nanoscale task such as nanolithography and nanoindenting is a challenging work that is beyond the capabilities of human sensing and precision. Since surface forces and intermolecular forces dominate over gravitational and other more intuitive forces of the macro world at the nanoscale, a user is not familiar with these novel nanoforce effects. In order to overcome this scaling barrier, haptic interfaces that consist of visual and force feedback at the macro world have been used with an Atomic Force Microscope (AFM) as a manipulator at the nanoscale. In this paper, a nanoscale virtual coupling (NSVC) concept is introduced and the relationship between performance and impedance scaling factors of velocity (or position) and force are explicitly represented. Experiments have been performed for nanoindenting and nanolithography with different materials in the nanoscale virtual surface. The interaction forces (non contact and contact nanoforces) between the AFM tip and the nano sample are transmitted to the operator through the haptic interface.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.121-126
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• 2012

Piezoresistive type contact force sensor array is fabricated by (111) Silicon bulk micromachining for continuous blood pressure monitoring. Length and width of the unit sensor structure is $200{\mu}m$ and $190{\mu}m$, respectively. The gap between sensing elements is only $10{\mu}m$. To achieve wafer level packaging, the sensor structure is capped by PDMS soft cap using wafer molding and bonding process with $10{\mu}m$ alignment precision. The resistance change over contact force was measured to verify the feasibility of the proposed sensor scheme. The maximum measurement range and resolution is 900 mm Hg and 0.57 mm Hg, respectively.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.88-91
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• 2005

Although the MEMS element is made through a very precise manufacturing process, usually there is the difference between the modeling design and the actual product. So tuning is required. Through the frequency tuning(changing the characteristics of device), we can calibrate the fabrication error and uncertainty. I'll propose the method of changing the natural frequency through the imposing the axial force on the anchor part to separate the sensing part and the tuning part. When the shape of section is the form of rectangular, the degree of the natural frequencies' change under axial force appears D be different. Applying a tuning force of 30 $\mu$N, the natural frequencies' difference can be reduced by 5 percent.

• The Journal of Korea Robotics Society
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• v.16 no.1
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• pp.1-11
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• 2021

Soft robotics has attracted a huge amount of interest in the recent decade or so, be it either actuators or sensors. Recently, a soft optical waveguide sensor has proven its effectiveness for various sensing applications such as strain, force, and bending measurements. The operation principle of the waveguide is simple, but the present technology is far too much complex to manufacture the waveguide. The waveguide fails to attract various practical applications in comparison to other types of sensors despite its superior safety and ease working principle. This study pursues to develop the soft sensors based on the optical phenomena so that the waveguide can be easily manufactured and its design can be conducted. Several physical properties of the waveguide are confirmed through the repetitive experiments in the aspects of strain, force, and bending of the waveguide. Finally, the waveguide sensor is embedded inside the actuator to verify the effectiveness of the proposed waveguide as well as to extend the application fields of the waveguide sensor.

• Smart Structures and Systems
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• v.13 no.6
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• pp.993-1014
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• 2014

In civil engineering, revolving structures (RS) are a unique structural form applied in innovative architecture design. Such structures are able to revolve around themselves or along a certain track. However, few studies are dedicated to safety design or health monitoring of RS. In this paper, a wireless dynamic sensing system is developed for RS, and field tests toward a large revolving auditorium are conducted accordingly. At first, a wheel-rail problem is proposed: The internal force redistributes in RS, which is due to wheel-rail irregularity. Then the development of the sensing system for RS is presented. It includes system architecture, network organization, vibrating wire sensor (VWS) nodes and online remote control. To keep the sensor network identifiable during revolving, the addresses of sensor nodes are reassigned dynamically when RS position changes. At last, the system is mounted on a huge outdoor revolving auditorium. Considering the influence of the proposed problem, the RS of the auditorium has been designed conservatively. Two field tests are conducted via the sensing system. In the first test, 2000 people are invited to act as the live load. During the revolving process, data is collected from RS in three different load cases. The other test is the online monitoring for the auditorium during the official performances. In the end, the field-testing result verifies the existence of the wheel-rail problem. The result also indicates the dynamic sensing system is applicable and durable even while RS is rotating.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.7
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• pp.2213-2222
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• 1996

This paper presents the design process and evaluaation results of a two-axis force transducer for measuring flange reaction forces. A double-cantilever beam structure is used as a sensing element, and its optimal configuration is determined based on the derived strain equations to maximize the sensitivity and minimize the regid body displacements. To reduce the coupling errors between two-axis forces, strain distributions by finite elemetns analysis are utilized and the Wheaststone bridge cricuits composed of strain gages are built such that the output voltage should be zero, although strains of four strain gages are not zero. Calibration test shows that the two-azxis force transducer developed in this paper is useful in measuring flange reaction forces within the coupling error of 5.53%.

• Fashion & Textile Research Journal
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• v.21 no.6
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• pp.697-707
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• 2019

This review paper deals with materials, classification, and a current article investigation on smart textile sensors for wearable vital signs monitoring (WVSM). Smart textile sensors can lose electrical conductivity during vital signs monitoring when applying them to clothing. Because they should have to endure severe conditions (bending, folding, and distortion) when wearing. Imparting electrical conductivity for application is a critical consideration when manufacturing smart textile sensors. Smart textile sensors fabricate by utilizing electro-conductive materials such as metals, allotrope of carbon, and intrinsically conductive polymers (ICPs). It classifies as performance level, fabric structure, intrinsic/extrinsic modification, and sensing mechanism. The classification of smart textile sensors by sensing mechanism includes pressure/force sensors, strain sensors, electrodes, optical sensors, biosensors, and temperature/humidity sensors. In the previous study, pressure/force sensors perform well despite the small capacitance changes of 1-2 pF. Strain sensors work reliably at 1 ㏀/cm or lower. Electrodes require an electrical resistance of less than 10 Ω/cm. Optical sensors using plastic optical fibers (POF) coupled with light sources need light in-coupling efficiency values that are over 40%. Biosensors can quantify by wicking rate and/or colorimetry as the reactivity between the bioreceptor and transducer. Temperature/humidity sensors require actuating triggers that show the flap opening of shape memory polymer or with a color-changing time of thermochromic pigment lower than 17 seconds.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.2
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• pp.133-145
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• 1996

This paper presents an indirect cutting force measuring system, which uses the current signals from the AC servo drive units of the horizontal machining center, with its applications to the adaptive regulation of the cutting forces in various milling processes and to the on-line monitoring of tool breakage. A typical model for the feed-drive control system of a horizontal machining center is developed to analyze cutting force measurement from the drive motor. The pulsating milling forces can be measured indirectly within the bandwidth of the current feedback control loop of the feed-drive system. It is shown that the indirectly measured cutting force signals can be used in the adaptive controller for cutting force regulation. The whole scheme has been embedded in the commercial machining center and a series of cutting experiments on the face cutting processes are performed. The adaptive controller reveals reliable cutting force regulating capability against the various cutting conditions. It is also shown that the tool breakage in milling can be detected within one spindle revolution by adaptively filtering the current signals. The effect of the cutter run-out has been considered for the reliable on-line detection of tool breakage.