• International Journal of Precision Engineering and Manufacturing
• /
• v.3 no.3
• /
• pp.5-11
• /
• 2002

This paper describes the methods for calibration and evaluation of the relative expanded uncertainty of a multi-axis force/moment sensor. In order to use the sensor in the industry, it should be calibrated and its relative expanded uncertainty should be also evaluated. At present, the confidence of the sensor is shown with only interference error. However, it is not accurate, because the calibrated multi-axis force/moment sensor has an interference error as well as a reproducibility error of the sensor, etc. In this paper, the methods fur calibration and for evaluation of the relative expanded uncertainty of a multi-axis force/moment sensor are newly proposed. Also, a six-axis force/moment sensor is calibrated with the proposed calibration method and the relative expanded uncertainty is evaluated using the proposed uncertainty evaluation method and the calibration results. It is thought that the methods fur calibration and evaluation of the uncertainty can be usually used for calibration and evaluation of the uncertainty of the multi-axis force/moment sensor.

• Journal of the Korean Society for Precision Engineering
• /
• v.24 no.10
• /
• pp.91-98
• /
• 2007

This paper describes the development of the calibration system for a multi-axis force/moment sensor and its uncertainty evaluation. This calibration system can generate the continuous forces (${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$) and moments (${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$). Many kinds of multi-axis force/moment sensors in industries should be carried out the characteristic test or the calibration with the calibration system that can generate the forces and the moments. The calibration systems have been already developed are the disadvantages of the low capacity, the generation of step forces(10N, 20N ...) and step moments(1Nm, 2Nm ...) with weights, the high coasts in manufacture and so on. In this paper, the calibration system for a multi-axis force/moment sensor that can generate the continuous three forces and three moments was developed. Their ranges are $0{\sim}2000N$ in all force-directions and $0{\sim}400Nm$ in all moment-directions. And the system was evaluated in the expanded relative uncertainty. They were ${\pm}0.0004$ in all forces ${\pm}Fx,\;{\pm}Fy$ and ${\pm}Fz$, and ${\pm}0.0004$ in all moments ${\pm}Mx,\;{\pm}My$ and ${\pm}Mz$.

• Tribology and Lubricants
• /
• v.28 no.6
• /
• pp.289-296
• /
• 2012

Atomic force microscopy (AFM) has been used for imaging surfaces and measuring surface forces at the nano-scale. Force calibration is important for the quantitative measurement of forces at the nano-scale using AFM. Normal force calibration is relatively straightforward, whereas the lateral force calibration is more complicated since the lateral stiffness of the cantilever is often comparable to the contact stiffness. In this work, the lateral force calibrations of the rectangular cantilever were performed using torsional Sader's method, thermal noise method, and wedge calibration method. The lateral optical lever sensitivity for the thermal noise method was determined from the friction loop under various normal forces as well. Experimental results showed that the discrepancies among the results of the different methods were as large as 30% due to the effect of the contact stiffness on the lateral force calibration of the cantilever used in this work. After correction for the effect of contact stiffness, all the calibration results agreed with each other, within experimental uncertainties.

• Tribology and Lubricants
• /
• v.29 no.2
• /
• pp.91-97
• /
• 2013

Quantifying the nanoscale force between the atomic force microscopy (AFM) probe of a force-sensing cantilever and the sample is one of the challenges faced by AFM researchers. The normal force calibration is straightforward; however, the lateral force is complicated due to the twisting motion of the cantilever. Force measurement in a liquid environment is often needed for biological applications; however, calibrating the force of the AFM probes for those applications is more difficult owing to the limitations of conventional calibration methods. In this work, an accurate nondestructive lateral force calibration method using multiple pivot loading was proposed for liquid environment. The torque sensitivity at the location of the integrated probe was extrapolated based on accurately measured torque sensitivities across the cantilever width along a few cantilever lengths. The uncertainty of the torque sensitivity at the location of the integrated tip was about 13%, which is significantly smaller than those for other calibration methods in a liquid environment.

• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.12
• /
• pp.161-167
• /
• 1999

This paper describes the calibration method and the calculation equations of expanded uncertainty for a precision electric force measuring device. The calibration of the electric force measuring device is performed three times (0 ${\circ}$(first time), $120{\circ}$(second time), $240{\circ}$(third time)) at each calibration point. It is usually selected ten points from zero load to rated load of the electric force measuring device. The expanded uncertainty is calculated by combining A type standard uncertainty and B type standard uncertainty. The calibration method and the calculation equations of expanded uncertainty can be widely used in the calibration of the precision electric force measuring device.

• Tribology and Lubricants
• /
• v.21 no.5
• /
• pp.221-226
• /
• 2005

A new calibration method for exact measurement of friction force in atomic force microscope (AFM) is presented. A new conversion factor involves a contact factor affected by tip, cantilever and contact stiffness. Especially the effect of contact stiffness on the conversion factor between lateral force and lateral signal is considered. Conventional conversion factor and a new modified conversion factor were experimentally compared. Results showed that a new calibration method could minimize the effect of normal load on friction force and improve the conventional method. A new method could be applied to the specimens with different physical properties.

• International Journal of Precision Engineering and Manufacturing
• /
• v.2 no.2
• /
• pp.11-16
• /
• 2001

This paper presents an in self-calibration method to corrent the Z-directional distortion of AFM(Atomic Force Microscopy).

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.68-72
• /
• 1997

This paper presents the design and the evaluation of the 6-component force/moment calibration machine which h a s t h e maximum capacities of 500 N in forces and 50 Nm in moments. This calibration machine consists of body. fixture. force generating system, moment generating system. The expanded uncertainty of the calibration machine is evaluated by calculating the A type uncertainty. $U_A$ and B type uncertainty, $U_B$. The evaluation results. this system has the expanded uncertainty of less than $2{\times}10^[-2]$ in respective force and moment components.

• Journal of the Korean Society for Precision Engineering
• /
• v.15 no.9
• /
• pp.127-134
• /
• 1998

This paper describes the design of a 6-component force/moment calibration machine with having the maximum capacities of 500 N in forces and 50 Nm in moments. To be used for the characteristic of a multi-component load cell. this machine consists of a body, a fixture, a force generating system, a moment generating system and weights. We have also evaluated the accuracy of the calibration machine. Test results show that the expanded relative uncertainty for force components $\pmFx,\;\pmFy\;and\;moment\;components\;\pmMx,\;\pmMy\;are\;less\; than\;8.6\times10^{-4}$, and force components +Fz, -Fz and moment components $\pmMz\;is\;less\;than\;1.6\times10^{-3},\;2.0\times10^{-5},\;1.7\times10^{-3}$ respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.59-62
• /
• 2005

Small force measurements ranging from 1 pN to $100{\mu}N$, we call it Nano Force, become the questions of common interests of biomechanics, nanomechanics, material researches, and so on. However, unfortunately, quantitative and accurate force measurements have not been taken so far. This is because there ,are no traceable force standards and a calibration scheme. This paper introduces a quantitative force metrology, which provides traceable link to SI (International Systems of Units). We realize SI traceable force ranging from 1 nN to $100{\mu}N$ using an electrostatic balance and disseminate it through transfer standards, which are self-sensing cantilevers that have integrated piezoresistive strain gages. We have been built a prototype electrostatic balance and Nano Force Calibrator (NFC), which is an AFM cantilever calibration system. As a first experiment, we calibrated normal spring constants of commercial AFM cantilevers using NFC. Calibration results show that the spring constants of them are quite differ from each other and nominal values provided by a manufacturer (up to 240% deviation).