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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 29, Issue 12 - Dec 2012
Volume 29, Issue 11 - Nov 2012
Volume 29, Issue 10 - Oct 2012
Volume 29, Issue 9 - Sep 2012
Volume 29, Issue 8 - Aug 2012
Volume 29, Issue 7 - Jul 2012
Volume 29, Issue 6 - Jun 2012
Volume 29, Issue 5 - May 2012
Volume 29, Issue 4 - Apr 2012
Volume 29, Issue 3 - Mar 2012
Volume 29, Issue 2 - Feb 2012
Volume 29, Issue 1 - Jan 2012
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The Measurement of the Magnitude of Sensory Perception and Displeasure to the Vibration Stimuli applied on Forearm in upper Limb Amputees
Kim, Sol-Bi ; Chang, Yun-Hee ; Kim, Shin-Ki ; Kim, Gyoo-Suk ; Mun, Mu-Sung ; Bae, Tae-Soo ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 705~710
DOI : 10.7736/KSPE.2012.29.7.705
Research involving discomfort or pain related to haptic vibratory stimulation the for prosthesis users of myoelectrical hand is very lacking. Our objective of this study was to evaluate the displeasure and sensitivity of areas in forearm using vibration stimulation system between upper limb amputees and non-amputees. Twenty transradial amputees and forty non-amputees (20 youth, 20 elderly) were involved. We set up custom-made vibration stimulation system including eight actuators (4 medial parts and 4 lateral parts) and GUI-based acquisition system, to investigate changes of residual somatosensory sensibility and displeasure at proximal 25% of forearm. Eight vibration actuators were attached to the circumference of proximal 25% point of forearm at regular intervals. Sensitivity tests were used to stimulate the 120Hz and discomfort experiment was used to 37 ~ 223Hz. The subjective responses were evaluated by 10 point scale. The results showed that both groups were similar in sensitive areas. Response at around of radius was most sensitive than other areas in all subjects. Elderly group do not appear discomfort of vibrotactile; however, youth group and amputee presented discomfort of vibrotactile. Prosthesis with a vibrotactile feedback system should be developed considering the sensitivity. Furthermore, Future studies should investigate the scope of application of that principle.
Effects of Modulation Type on Electrically-Elicited Tactile Sensation
Hwang, Sun-Hee ; Ara, Jawshan ; Song, Tong-Jin ; Bae, Tae-Sue ; Park, Sang-Hyuk ; Khang, Gon ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 711~716
DOI : 10.7736/KSPE.2012.29.7.711
The purpose of this study was to investigate how the modulation method affects the effectiveness of eliciting tactile sensations by electrical stimulation. Two methods were employed and the results were compared and analyzed; pulse amplitude modulation (PAM) and pulse width modulation (PWM). Thirty-five healthy subjects participated in the experiments to measure the stimulation intensity that began to elicit a tactile sensation - activation threshold (AT). Constant-current monophasic rectangular pulse trains were employed, and the stimulation intensity was varied from zero until the subject felt any uncomfortable sensation. The step size of the stimulation intensity was 100nC/pulse. After each experiment, the subject described the sensation both quantitatively and qualitatively. The two modulation methods did not make a significant difference as far as the AT values were concerned, but most of the subjects showed 'intra-individual' consistency. Also, it was confirmed that our range of the stimulation parameters enabled us to obtain three major tactile sensations; tickling, pressure and vibration. The results suggested that the stimulation parameters and the modulation type should be selected for each individual and that selective electrical stimulation of the mechanoreceptors needs more diversified researches on the electrode design, multi-channel stimulation protocol, waveforms of the pulse train, etc.
Dynamic Modeling and Design of Finger Exoskeleton Using Polymer Actuator
Jeong, Gwang-Hun ; Kim, Yoon-Jeong ; Yoon, Bye-Ri ; Wang, Hyuck-Sik ; Song, Dae-Seok ; Kim, Sul-Ki ; Rhee, Kye-Han ; Jho, Jae-Young ; Kim, Dong-Min ; Lee, Soo-Jin ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 717~722
DOI : 10.7736/KSPE.2012.29.7.717
This paper presents the design and dynamic model of the finger exoskeleton actuated by Ionic Polymer Metal Composites (IPMC) to assist a tip pinch task. Although this exoskeleton will be developed to assist 3 degree-of-freedom motion of each finger, it has been currently made to perform the tip pinch task using 1 degree-of-freedom mechanism as the first step. The six layers of IPMC were stacked in parallel to increase the low actuation force of IPMC. In addition, the finger dummy was manufactured to evaluate the performance of the finger exoskeleton. The pinch task experiments, which were performed on the finger dummy with the developed exoskeleton, showed that the pinch force close to the desired level was obtained. Moreover, the dynamic model of the exoskeleton and finger dummy was developed in order to perform the various analyses for the improvement of the exoskeleton.
Changes of Lower Limb Joints Stiffness with Gait Speed in Knee Osteoarthritis
Park, Hee-Won ; Park, Su-Kyung ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 723~729
DOI : 10.7736/KSPE.2012.29.7.723
Spring-like leg models have been employed to explain various dynamic characteristics in human walking. However, this leg stiffness model has limitations to represent complex motion of actual human gait, especially the behaviors of each lower limb joint. The purpose of this research was to determine changes of total leg stiffness and lower limb joint stiffness with gait speed in knee osteoarthritis. Joint stiffness defined as the ratio of the joint torque change to the angular displacement change. Eight subjects with knee osteoarthritis participated to this study. The subject walked on a 12 m long and 1 m wide walkway with three sets of four different randomly ordered gait speeds, ranging from their self-selected speed to maximum speed. Kinetic and kinematic data were measured using three force plates and an optical marker system, respectively. Joint torques of lower limb joints calculated by a multi-segment inverse dynamics model. Total leg and each lower limb joint had constant stiffness during single support phase. The leg and hip joint stiffness increased with gait speed. The correlation between knee joint angles and torques had significant changed by the degree of severity of knee osteoarthritis.
Study on Gait Analysis of Elders and Hemiplegia Patients using 3D Motion Analysis
Jang, Hye-Youn ; Han, Jung-Soo ; Han, Chang-Soo ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 730~736
DOI : 10.7736/KSPE.2012.29.7.730
Latest, many researchers do research on wearable robot. The purpose of the researches is very diverse, it will improve efficiency in the industry, taken to replace the many workers in the military field and taken to assist bodily functions run out by aging. However, there is no clear Differentiated strategy depending on the purpose for design and control of the wearable robot. Although a common purpose is to drive the robot by the sensor signal (intent signals), the optimization about the mechanism and control studies must be done according to the user's physical ability and purpose. In this study, the study's first phase for the development of wearable robotic gait rehabilitation, gait characteristics were analyzed elders and hemiplegia patients using a 3D gait analysis system (VICON512). As a result, asymmetric gait characteristics of the hemiplegia patients were found compared with the normal elderly.
A Proton Beam Shaping using an Extreme Aspect Ratio Micro-hole
Kim, Jin-Nam ; Kwon, Won-Tae ; Lee, Seong-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 737~744
DOI : 10.7736/KSPE.2012.29.7.737
EDM is the manufacturing process that uses the thermal energy to machine electrically conductive part. Despite a lot of research has been conducted for decades, the best aspect ratio of the micro hole using micro-EDM has not been over 30, yet. In the present study, new fabrication scheme was introduced to increase the aspect ratio of micro hole dramatically. Micro holes with less than 10 aspect ratio were aligned and welded together to manufacture a micro hole with extreme aspect ratio. Alignment of the micro hole with over 380 aspect ratio was conducted by the home-made apparatus installed with microscope and laser beam. The micro hole with extreme aspect ratio was used to shape pencil beam from proton beam generated from MC-50 cyclotron. The pencil beam was utilized to machine test specimen whose result was compared with GEANT4 computer simulation. It was shown that the experimental and simulation result were closer as the aspect ratio of the micro hole was bigger.
A Study on the Pivot Steering Control of an In-Wheel Drive Vehicle with Trailing Arm Suspensions
Kim, Chi-Ung ; Lee, Kyoung-Hoon ; Woo, Kwan-Je ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 745~752
DOI : 10.7736/KSPE.2012.29.7.745
The pivot steering of an individual wheel motor drive vehicle is an effective steering maneuver in the narrow road, but it has become a matter of concern that the torque input of each wheel is very difficult to determine. In this study, the independent yaw moment control was proposed for the smooth pivot steering control of an in-wheel drive vehicle. For this control method, the vertical forces of tires were estimated from the trailing arm dynamic model, and the yaw moments of individual wheels were calculated from the vehicle dynamic model. Dynamic simulation results showed that the independent yaw moment control was much more effective on the minimization of the instabilities of pivot steering in comparison with the conventional direct yaw moment control with yaw rate feedback.
Development of Hand and Fingers Fixing System for Stroke Patient's Rehabilitation Exercise
Kim, Hyeon-Min ; Kim, Gab-Soon ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 753~761
DOI : 10.7736/KSPE.2012.29.7.753
This paper describes development of a hand and finger fixing system for the rehabilitation exercise of patient's fingers. In order to exercise the finger rehabilitation using a finger rehabilitation robot, a patient's hand or fingers are fixed safely. In this paper, The hand and fingers fixing system can safely fix stroke patient's hand and fingers by pressing with force control system. The characteristic test of the system was carried out. It is thought that the system could be used for fixing their fingers in stroke patient's finger rehabilitation exercise.
A Study on a Localization System for Tour Guide Robot
Lim, Jong-Hwan ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 762~769
DOI : 10.7736/KSPE.2012.29.7.762
The localization system for tour guide robot was developed which is inevitable and important for the guide robot in order to guide the tourists and explain the history or contents of the site. The localization system is based on the non-inertial sensors such as a DGPS, Dead-Reckoning. The information of the DGPS is used to update the estimated positions from Dead Reckoning. The extended Kalman filter was used for the fusion of the measured information from the sensors and estimated positions by Dead Reckoning. The simulation results show that it is very reliable and the position error is bounded within a certain extend.
Design and Analysis a Drive-train for a Parallel-type Hybrid Electric Vehicle
Kim, Dong-Hyun ; Ahn, Sung-Jun ; Choi, Jae-Weon ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 770~777
DOI : 10.7736/KSPE.2012.29.7.770
This paper deals with the design and modal characteristics analysis of a drive-train for a paralleltype hybrid electric vehicle (HEV). The function of the drive-train system (DTS) in the HEV combines or divides the torque and velocity from the internal combustion engine along with the induction motor. The system consists of a compound planetary gear and unit's electromagnetic clutch to provide the operation modes such as Engine Only (EO), Electric Vehicle (EV), and Hybrid Electric Vehicle (HEV) modes. In order to investigate the characteristics of the velocity and torque flow for the system, dynamic models of the HEV with DTS are derived from the prototype DTS. The performance of the derived dynamic models is evaluated by both computer simulations and experiments according to each mode.
Evaluation on the Cooling Performance to Design Heat sinks for LED lightings
Jung, Tae-Sung ; Kang, Hwan-Kook ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 778~784
DOI : 10.7736/KSPE.2012.29.7.778
In comparison with some other light sources, LED has merits such as increased life expectancy, fast response, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED has widely used in many industrial fields such as automotive, aviation, display, transportation and special lighting applications. Since the high heat generation of LED chips can cause a reduction in lifetime, degradation of luminous efficiency, and variation of color temperature, studies have been carried out on the optimization of LED packaging and heat sinks. In this study, experiments on measuring the heat generation rate of LED and the cooling performance of a heat sink were carried for analyzing the thermal characteristics of LED lighting system in free convection. From the results, dimensionless correlation on the cooling performance of heat sink in natural convection was proposed with Nusselt number and Rayleigh number as a guideline for designing cooling device of LED lightings.
Modeling of the Elasto-plastic Deformation Behavior of Two-Dimensional Anisotropic Foam under Compressive Loads using Voronoi Cells
Han, Won-Hee ; Choi, Byoung-Ho ; Kim, Il-Hyun ; Lee, Jeong-Moo ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 785~792
DOI : 10.7736/KSPE.2012.29.7.785
Foam structure is usually hard to model due to the complexity of the geometry of cells. So, many simplified models to represent complicated foam structures have been proposed, but most of them are not actually describe the random feature of the cell structure well. So, in this study, two dimensional isotropic and anisotropic closed cell structures of the foam were modeled using the concept of Voronoi cells. The elasto-plastic deformation behavior under compressive loads was investigated by finitie element analysis, and the results were compared with ideal honeycomb structure. In addition, the effect of anisotropy of Voronoi cell structures of the foam on Young's modulus and yield stress under compressive loads was studied.
Vibration Analysis for Oil Gear Motor considering Pulsation Pressure
Shin, Yoo-In ; Yi, Chung-Seob ; Jeong, Ung-Gi ; Suh, Jeong-Se ; Song, Chul-Ki ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 793~798
DOI : 10.7736/KSPE.2012.29.7.793
Oil gear pump is used for the cooling pump system of commercial vehicle. The hydraulic pulsation pressure of oil gear pump is one of the most important reasons for the vibration and noise of the pump. In this study, the several hydraulic factors acting on oil gear motor are analyzed by CFD in operation of cooling system. Forced vibration analysis due to hydraulic pulsation pressure is analyzed by FEA for predicting deformation and equivalent stress.
Rapid Fabrication of Micro-nano Structured Thin Film for Water Droplet Separation using 355nm UV Laser Ablation
Shin, Bo-Sung ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 799~804
DOI : 10.7736/KSPE.2012.29.7.799
Recently micro-nano structures has widely been reported to improve the performance of waterproof, heat isolation, sound and light absorption in various fields of electric devices such as mobiles, battery, display and solar panels. A lot of micro-sized holes on the surface of thin film provide excellent sound, or heat, or light transmission efficiency more than solid film and simultaneously nano-sized protrusions around micro hole increase the hydrophobicity of the surface of thin film because of lotus leaf effects as generally known previously. In this paper new rapid fabrication process with 355 nm UV laser ablation was proposed to get micro-nano structures on the surface of thin film, which have only been observed at higher laser fluence. Developed thin micro-nano structured film was also investigated the hydrophobic property by measuring the contact angle and demonstrated the possibility to apply to water droplet separation.
Changes of Muscle Activation Pattern of Trunk Muscles during Whole-body Tilts with and without Axial Rotation
Kim, Sol-Bi ; Chang, Yun-Hee ; Kim, Shin-Ki ; Bae, Tae-Soo ; Mun, Mu-Seong ; Park, Jong-Chul ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 7, 2012, Pages 805~810
DOI : 10.7736/KSPE.2012.29.7.805
Determining of the exercise intensity is very important in terms of induction of low fatigue during exercise. Little information is available on the contraction level of the trunk muscles during whole body tilts with and without axial rotation. This study was to investigate the difference muscle activation level according to axial rotation. Twenty subjects were participated. The muscle activities of the five trunk muscles were bilaterally measured at eight axial rotation angles with 12 tilt angles along
intervals. The results showed that tilt with
axial rotation was more balanced in the same tilt angle and was maintained approximately level of 40% MVC at over
tilt angle with respect to co-contraction of abdominal and back muscle. Lumbar stabilization exercise using whole body tilts would be more effective with axial rotation than without axial rotation in terms of muscle co-contraction.