• Journal of Mechanical Science and Technology
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• v.20 no.5
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• pp.668-674
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• 2006

In order to develop a cell based robot, we present a micro-mechanical force measurement system for the biological muscle actuators, which utilize glucose as a power source. The proposed measurement system is composed of a micro-manipulator, a force transducer with a glass probe, a signal processor, an inverted microscope and video recording system. Using this measurement system, the contractile force and frequency of the cardiac myocytes were measured in real time and the magnitudes of the contractile force of each cardiac myocyte under different conditions were compared. From the quantitative experimental results, we could estimate that the force of cardiac myocytes is about $20\sim40{\mu}N$, and show that there are differences between the control cells and the micro-patterned cells.

• Journal of Mechanical Science and Technology
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• v.18 no.5
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• pp.789-797
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• 2004

The nanoscale sensing and manipulation have become a challenging issue in micro/nano-robotic applications. In particular, a feedback sensor-based manipulation is necessary for realizing an efficient and reliable handling of particles under uncertain environment in a micro/nano scale. This paper presents a piezoresistive MEMS cantilever for nanoscale force measurement in micro robotics. A piezoresistive MEMS cantilever enables sensing of gripping and contact forces in nanonewton resolution by measuring changes in the stress-induced electrical resistances. The calibration of a piezoresistive MEMS cantilever is experimentally carried out. In addition, as part of the work on nanomanipulation with a piezoresistive MEMS cantilever, the analysis on the interaction forces between a tip and a material, and the associated manipulation strategies are investigated. Experiments and simulations show that a piezoresistive MEMS cantilever integrated into a micro robotic system can be effectively used in nanoscale force measurements and a sensor-based manipulation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.2
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• pp.147-152
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• 1999

Semiconductor piezoresistive type vibration sensor was fabricated by using semiconductor process and micromachining technology. To measure the micro electromagnetic force between coil and magnet, fabricated vibration sensor was used. Toapply micro electromagnetic force produced from the micro exciter, small-sized NdFeB permanent magnet was attached on the mass of the fabricated vibration sensor. The measured electromagnetic force are about 5~180dyne when the applied sinusoidal current of 1KHz in the range of 1.5~8mA. The measurement of micro electromagnetic forcewas performed by changing the distance between coil and magnet. Output characteristics of micro electromagnetic force according to the applied coil current were linear. Furthermore, output results were used to get the transfer constant that is important to decide the efficiency and the performance of the coil and magnet.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1179-1182
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• 2005

To facilitate the cell based robot research, we presented a micro-mechanical force measurement system for the biological muscle actuators, which utilize glucose as a power source for potential application in a human body or blood vessels. The system is composed of a micro-manipulator, a force transducer with a glass probe, a signal processor, an inverted microscope and video recoding system. Using this measurement system, the contractile force and frequency of the cardiac myocytes were measured in real time and the magnitude of the contractile force of each cardiac myocyte on a different condition was compared. From the quantitative experimental results, we estimated that the force of cardiac myocytes is about $20{\sim}40\;{\mu}$N, and showed that there is difference between the control cells and the micro-patterned cells.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2445-2450
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• 2003

Recently, biological technology industry shows great development. Instruments and systems related biological technology have been developed actively. In this paper, we developed a new micro end-effector for biological cell manipulation. The existing micro end-effector for biological cell manipulation has not any force sensing mechanism. Usually, excessive contact force occurring when the end-effector and a cell collide might make a damage on the cell. However, unfortunately, user can not notice the condition in case of using the existing end-effector. In order to overcome we proposed the improved micro end-effector having a force sensing mechanism. This paper presents the design concepts of the new micro end-effector. We carried out calibration of the force sensor and tested the performance of the proposed micro end-effector. Through a series of experiments the new micro end-effector shows the possibility of application for precision biological cell manipulation such as DNA operation

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.104-111
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• 2003

Micro force measurement is required more frequently for a precision manufacturing and investment in fields of precision industries such as semiconductor, chemistry and biology, and so forth. Null balance method has been introduced as an alternative of a loadcell. Loadcells have advantages in aspects of low cost and easy manufacturing, but have also the limitation in resolution and sensitivity to environment variations. In this paper, null balance method is explained and the dominant parameters related to system performances are mentioned. Null position sensor, electromagnetic system and controller are investigated. Also, the characteristic experiment is carried out in order to estimate the resolution and the measurement range. In order to overcome the limitation by the drift of position sensor and the performance of controller, double electromagnetic force compensation method is proposed and experimented. After controlling and filtering, the resolution under $\pm$ 1mg and measurement range over 300g could be obtained.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.53-59
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• 2004

In this paper, we propose a new multi-purpose Scanning Force Microscope (SFM) system. The system can be used for nano/micro-scratching, in-process profile measurement, and observation of potential surface defects which occur during the scratching in air or liquid. Experimental results of nano/micro-scratching show that the smallest scratching depth can be controlled to be 10nm, which corresponds to the stability of the SFM system. Profile measurements of nano/micro-scratching surfaces have also been performed by the method of on-machine measurement and in-process measurement. Two measurement results were in good agreement with each other. The maximum difference was approximately 10 nm, which was mainly caused by the sampling repeatability error that influences the measurement accuracy Also, micro-defects on the micro-scratching surface were successfully detected by the SFM system. It was confirmed that the number of micro-defects increases when the surface is subjected to a cyclic bending load. The maximum depth was less than 100nm.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.163-164
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• 2007

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.1
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• pp.75-84
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• 2003

In this paper, a new nano/micro-mechanical processing test machine was developed. This new test machine, which is based on the principle of the scanning force controlled probe microscope, can realize nano/micro-mechanical machining and in-process profile measurement. Experimental results of nano/micro indentation and scratching show that the controllable cutting depth of the test machine can be controlled by PZT actuator. Profile measurement of the machined surface has also been performed by using the test machine and a conventional AFM(Atomic Force Microscopy). A good agreement of the two measurement results have been achieved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1029-1032
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• 2002

This paper describes a design of a tactile sensor, which can measure three components force and temperature due to thermal conductive. The bio-mimetic tactile sensor, alternative to human's finger, is comprised of four micro force sensors and four thermal sensors, and its size being 10mm$\times$10mm. Each micro force sensor has a square membrane, and its force range is 0.1N - 5N in the three-axis directions. On the other hand, the thermal sensor for temperature measurement has a heater and four temperature sensor elements. The thermal sensor is designed to keep the temperature. $36.5^{\circ}C$, constant, like human skin, and measure the temperature $0^{\circ}C$ to $50^{\circ}C$. The MEMS technology is applied to fabricate the sensing element of the tactile sensor.