• Journal of the Korean Society for Precision Engineering
• /
• v.32 no.8
• /
• pp.743-748
• /
• 2015

This paper reports the enhanced fabrication and characterization of a $3{\times}3$ array tactile actuator composed of cellulose acetate. The array tactile actuator, with dimensions of $15{\times}15{\times}1mm^3$, consists of 9 pillar-supported cells made from a cellulose-acetate molding. The fabrication process and performance test along with the results for the suggested actuator are explained. To improve the cell-array fabrication, a laser cut was adopted after the molding process. The displacement of the unit cell increased the input voltage and frequency. Various top masses are added onto the actuator to mimic the touch force, and the acceleration of the actuator is measured under actuation. When 2 kV is applied to the actuator, the maximum acceleration is 0.64 g, which is above the vibrotactile threshold. The actuation mechanism is associated with the electrostatic force between the top and bottom electrodes.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.2
• /
• pp.457-462
• /
• 2004

Bambusae Caulis in Liquamen has been used as a herbal medicine for the treatment of heat, paralysis of the hands or feet, or hemiplegia. In the present study, we investigated the effect of Bambusae Caulis in Liquamen to the phenylephrine (PE) induced contraction of isolated rat aorta Contractile force was measured with force displacement transducer under 1.5 g loading tension. Contractions evoked by PE 0.1 μM were significantly increased by low dosage of Bambusae Caulis in Liquamen, decreased by high dosage of Bambusae Caulis in Liquamen. L-NNA, ODQ and propranolol significantly altered the effect of Bambusae Caulis in Liquamen, but indomethacin did not change the relaxation of Bambusae Caulis in Liquamen. These results suggest that Bambusae Caulis in Liquamen can relax EP induced contraction of isolated rat aorta and that this decreasing contraction related to sympathetics.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.5
• /
• pp.1299-1304
• /
• 2003

This study is to determine the effect of Fructus Rubi to the phenylehrine (PE) induced contraction of isolated rat aorta. Contractile force was measured with force displacement transducer under 1.5g loading tension. Contractions evoked by PE 0.1 μM and KCI 65.4 mM were decreased significantly by Fructus Rubi. L-NNA, ODQ, indomethacin and atropine significantly altered the effect of Fructus Rubi, but propranolol did not change the relaxation of Fructus Rubi. These results indicate that Fructus Rubi can relax EP and KCI induced contraction of isolated rat aorta and that this decreasing contraction related to epithelium, nitric oxide, and parasympathetics.

• 한국HCI학회:학술대회논문집
• /
• 2008.02c
• /
• pp.19-24
• /
• 2008

This paper presents a physically-based haptic rendering algorithm for a deformable object based on visual information about the intervention between a tool and a real object in a remote place. The physically-based model of a deformable object is created from the mechanical properties of the object and the captured image obtained with a CCD camera. When a slave system exerts manipulation tasks on a deformable object, the reaction force for haptic rendering is computed using boundary element method. Snakes algorithm is used to obtain the geometry information of a deformable object. The proposed haptic rendering algorithm can provide haptic feedback to a user without using a force transducer in a teleoperation system.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.29 no.6
• /
• pp.363-368
• /
• 2017

The tsunami flood the coastal cities and damage the land structures. The study on wave pressure and force on land structures is one of the important factors in designing the stability of inland structures. In this study, two - dimensional wave flume tests on the horizontal wave force and pressure of tsunamis on a simplified box-type structure was conducted. Vertical distribution and wave power of horizontal wave pressure over time were measured by pressure sensors and force transducer. Also, those were measured from the different wave breaking types. The vertical distribution of horizontal wave pressure was uniform at the moment when the horizontal wave force to the structure was maximum under the breaking wave condition. A surf similarity parameter was employed in order to figure out the relationship between the maximum horizontal wave force on the structure as a function of various incident wave conditions. As a result, the non - dimensionalized horizontal wave force tends to decrease exponentially as the surf similarity parameter increases.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2009.04a
• /
• pp.93-96
• /
• 2009

바퀴동력계는 차량에 지면으로부터 전달되는 힘과 모멘트를 측정하는 로드셀이다. 본 연구에서 개발한 바퀴동력계는 스트레인 게이지식 로드셀로써 이러한 로드셀을 설계하는데 있어서 몇가지 고려해야 하는 사항이 있다. 우선 스트레인 게이지를 부착하기 쉬운 구조가 되어야 하고 조립시의 오차를 줄이기 위하여 한 몸체로 제작되어야 한다. 이와 동시에 가장 중요하게 고려되어야 하는 인자로 감도를 위해 재료가 허용하는 응력내에서 되도록 큰 변형률이 발생해야 하고 상호 간섭 오차가 발생하지 말아야 한다. 본 연구에서는 수식을 이용하여 이론적으로 상호 간섭 오차를 0으로 만들 수 있었다. 또한 설계 변수 및 재료 물성치의 산포를 고려한 신뢰성 기반 최적설계 기법을 사용하였으며, 이를 통해 허용 응력하에서 최대의 변형률이 발생하는 바퀴동력계를 설계하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.154-157
• /
• 2002

A cyto-indentation technique was used to obtain the biomechanical compressive compliance property of an chondrocyte cell attached to glass surface, which was tried to generate joint cartilage by tissue engineering. Piezo-transducer system and dual photo-diode system were used to conduct mechanical indentation through displacement-controlled testing and the measurement of corresponding cell reaction force. The Poisson's ratio of 0.37 was quoted from other report. The compressive compliance of chondrocyte, that was determined by elastic contact theory, was 1.38${\pm}$0.057 kPa. This value is 30% higher than that of MG63 osteoblast-like cell. The cyto-indentation technique employed in this study is so precise that it can quantify the biomechanical property of single cell.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.3
• /
• pp.23-31
• /
• 1995

The sending characteristics of the non-contact type displacement transducers can affect the performances of the magnetic bearing systems when they support the rotating shaft. The probe type displacement sensor detects not only the displacement of the rotor at the sensing position but also the surface irregularitis of the rotor such as surface roughnessand roundness errors. If there exist such measuring errors, the magnetic bearing can not apply proper force against the rotor displacements for the detected signal is the input to the magnetic bearing controllers. The cylindrical shape capacitive transducer can detect the rotor displacement by the integral sum of the charges which are formed between the sensor plates and rotor so that it can reduce the detecting errors induced by the surface irregularities of the rotor. By theore- tical analysis, we compared the sensing characteristics of the cylindrical shape capacitive transducers for the rotors that have some sinusoidal irregularities with that of the ideal probe type displacement transducers.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.04a
• /
• pp.224-229
• /
• 2008

With the wide use of mobile phones, a paging signal by a sound transducer acts as an environmental noise on many occasions, thus necessitating an alternative paging signal by a vibration motor. Conventional vibration motors employ three-phase windings with mechanical brushes for commutation. In this paper, a new one-phase brushless and sensorless vibration motor is introduced utilizing digital signal processor chips in cell-phones. For electromagnetic field analysis, two-dimensional modeling can be implemented to determine the back electromotive force using axisymmetric boundary conditions. Geometric design parameters, such as coil pitch and magnet pitch. are considered for performance optimization. Through the experiments, it is shown that the proposed design has the equivalent performance with reduced number of parts, thus enhancing manufacturing productivity and reducing manufacturing cost.

• Proceedings of the KIEE Conference
• /
• 1989.07a
• /
• pp.34-36
• /
• 1989

Since the linear step motor(LSM) has the merits which can be controlled the position and velocity by using the micro-computer and has no mechanical transducer such as belt and gear, it's usefullness has been fitted for the printer, x-y plotter, OA machinery and so on. In designing the LSM, we are faced up to the calculation of forces. in this paper, the permeance modeling method suited for the design of transverse flux type linear step motor(TFM) is presented and simulated.