• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.3
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• pp.365-371
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• 2016

The electromechanical brake (EMB) is one of future brake systems due to its many advantages. For implementation of the EMB, the correct feed back about clamping force is necessary. Keeping commercialization of the EMB in mind, it is strongly demanded that an expensive load cell measuring the clamping force is replaced with an estimation algorithm. In addition, an estimation of the kissing point where the brake pads start to come into contact with a disk wheel is proposed in this paper. With these estimation algorithms, the clamping force can be expressed as a polynomial characteristic curve versus the motor angle. Also, a method for calibration of measured values by the load cell is proposed and used for an actual characteristic curve. Lastly, the performance of the proposed algorithms is evaluated in comparison with the actual curve on a developed EMB test bench.

• Tribology and Lubricants
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• v.28 no.5
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• pp.203-211
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• 2012

Atomic force microscopy (AFM) has been used as a tool, not only for imaging surfaces, but also for measuring surface forces and mechanical properties at the nano-scale. Force calibration is crucial for quantitatively measuring the forces that act between the AFM probe of a force sensing cantilever and a sample. In this work, the lateral force calibrations of a V-shaped cantilever were performed using the finite element method, multiple pivot loading, and thermal noise methods. As a result, it was shown that the multiple pivot loading method was appropriate for the lateral force calibration of a V-shaped cantilever. Further, through crosschecking of the abovementioned methods, it was concluded that the thermal noise method could be used for determining the lateral spring constants as long as the lateral deflection sensitivity was accurately determined. To obtain the lateral deflection sensitivity from the sticking portion of the friction loop, the contact stiffness should be taken into account.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.2
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• pp.484-491
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• 1990

A heat-flux meter has been designed and manufactured to measure the heat flux from the flame. A calibration method of the heat-flux meter by a calibration furnace has also been proposed. The k-type (Chromel-Alumel) thermocouple material has been used as the material for the beat-flux meter. The electormotive force (e.m.f.) from the K-type thermocouple is shown to be linearly proportional to the heat flux absorbed. The characteristics of the heat-flux meter become better as the radius of heat absorbing disk becomes larger and its thickness thinner.

• Proceedings of the Korean Vacuum Society Conference
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• 2002.06a
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• pp.136-136
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• 2002

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.251-255
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• 2003

This paper presents the design, fabrication, and calibration of a piezoelectric polymer-based sensorized microgripper. Electro discharge machining technology is employed to fabricate super-elastic alloy based micro gripper. It is tested to present improvement of mechanical performance. For integration of force sensor on the micro gripper, the sensor design based on the piezoelectric polymer PVDF film and fabrication process are presented. The calibration and performance test of force sensor integrated micro gripper are experimentally carried out. The force sensor integrated micro gripper is applied to perform fine alignment tasks of micro opto-electrical components. It successfully supplies force feedback to the operator through the haptic device and plays a main role in preventing damage of assembly parts by adjusting the teaching command.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.10
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• pp.1772-1777
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• 2003

This paper presents the design, fabrication, and calibration of a piezoelectric polymer-based sensorized microgripper. Electro discharge machining technology is employed to fabricate super-elastic alloy based micro gripper. It is tested to present improvement of mechanical performance. For integration of force sensor on the micro gripper, the sensor design based on the piezoelectric polymer PVDF film and fabrication process are presented. The calibration and performance test of force sensor integrated micro gripper are experimentally carried out. The force sensor integrated micro gripper is applied to perform fme alignment tasks of micro opto-electrical components. It successfully supplies force feedback to the operator through the haptic device and plays a main role in preventing damage of assembly parts by adjusting the teaching command.

• KSTLE International Journal
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• v.7 no.1
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• pp.5-9
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• 2006

The main principle of two widely used methods which were proposed by Ruan and Bhushan, and by Ogletree and Carpick are introduced. Experiments were conducted using the two methods to measure friction force between AFM probe and silicon sample quantitatively. To characterize the frictional properties, the conversion factors of the two methods by which lateral electronic signal is converted into actual friction force were calculated. The experimental results show that that the conversion factors were extraordinarily different from each other. Further research should be done to identity the reasons for these differences.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.12
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• pp.1906-1913
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• 2004

A new method has been proposed for the calibration of frictional forces in atomic force microscopy. Angle conversion factor is defined using the relationship between torsional angle and frictional signal. Once the factor is obtained from a cantilever, it can be applied to other cantilevers without additional experiments. Moment balance equations on the flat surface and top edge of a commercial step grating are used to obtain angle conversion factor. Proposed method is verified through another step grating test and frictional behavior of Mica.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.846-851
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• 2004

A new method has been proposed for the calibration of frictional forces in atomic force microscopy. Angle conversion factor is defined using the relationship between torsional angle and frictional signal. Once the factor is obtained from a cantilever, it can be applied to other cantilevers without additional experiments. Moment balance equations on the flat surface and top edge of a commercial step grating are used to obtain angle conversion factor. Proposed method is verified through another step grating test and frictional behavior of Mica.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.637-640
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• 2005

In this paper, we investigate the characteristics of a piezoresistive AFM cantilever in the range of $0\~30{\mu}N$ by using nano force calibrator (NFC), which consists of a high precision balance with resolution of 1 nN and 1-D fine positioning stage. Brief modeling of the cantilever is presented and then, the calibration results are shown. Tests revealed a linear relationship between the probing force and sensor output (resistance change), and the force vs. deflection. From this relationship, the force constant of the cantilever was calculated to 3.45 N/m with a standard deviation of 0.01 N/m. It shows that there is a big difference between measured and nominal spring constant of 1 N/m provided by the manufacturer s specifications.