• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1179-1184
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• 2007

An unmaned surveillance robot consists of rifle, laser receiver, thermal imager, color CCD camera, and laser illuminator. A human guard can be replaced with such a robot to take care dangerous surveillance tasks. Currently most of surveillance robots are mounded at a fixed post to take care of surveillance tasks. In order to watch blind areas, it is necessary to modify such a surveillance robot to become a mobile robot. In this paper, simulation based design procedure of mobile surveillance robot has been introduced. 3D CAD geometry model has been produced using Pro-Engineer. Required pen and tilt motor capacities have been analyzed using ADAMS inverse dynamics analysis. A target tracking and stabilization control algorithm of the mobile surveillance robot has been developed in order to stabilize the system from the motion of the vehicle which experiences the rough terrain. ADAMS-Matlab co-simulation has been also carried out to validate the proposed target tracking and stabilization algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.7
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• pp.749-753
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• 2013

Hydraulic systems are used to transform mechanical energy and fluid energy into each other. Its applications are very wide over the whole industries such as automobiles, public works, rockets, machine tools, construction heavy equipments, airplaces and so on. They are hydraulic pumps that transform energy in the systems. In this study, with basic operation principles as a start point, I tried to understand how the rotating radius of a piston affects the lubrication characteristics in more practical conditions, a swash-plate with tilt angle zero capable of rotating motion and other devices was used. In this paper, a slipper was located on 45mm eccentricity from the center of a swash-plate. As a result, through this experiment, it was found that the rotating radius of a piston affects load capacity, leakage flow and lubrication characteristics and it is one of the important parts for improving the pump efficiency.

• The Journal of Korean Physical Therapy
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• v.25 no.2
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• pp.117-125
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• 2013

Purpose: The purpose of this study was to investigate changes in movement strategies of lower limb joints depending on the type of heel during sit-to-stand. Methods: Twenty healthy females participated in this study. All subjects performed sit-to-stand three times each with three different types of heels - bare feet, 9 cm high-heeled shoes, and unstable shoes. Trails were conducted in random order. Three-dimensional motion analysis systems were used for collection and analysis of the kinematic data of lower limb movements. Results: Results of this study showed kinematic differences in pelvis, hip joints, knee joints, and ankle joints during sit-to-stand based on the type of heels. At the initial sit-to-stand, hip joint flexion, knee joint flexion, ankle joint flexion, and ankle joint inversion showed significant differences. The maximal angles of hip joint flexion, hip joint adduction, knee joint flexion, ankle joint flexion, and ankle joint inversion were significantly different, while hip joint adduction, pelvic forward tilt, hip joint rotation, knee joint flexion, ankle joint flexion, and ankle joint inversion differed significantly during the terminal of sit-to-stand. Conclusion: Therefore, the type of heel played an important role in selection of lower limb movements during sit-to-stand which were essential parts of daily life movements.

• Journal of Sensor Science and Technology
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• v.25 no.3
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• pp.202-207
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• 2016

Estimation of vertical position is critical in applications of sports science and fall detection and also controls of unmanned aerial vehicles and motor boats. Due to low accuracy of GPS(global positioning system) in the vertical direction, the integration of IMU(inertial measurement unit) with the GPS is not suitable for the vertical position estimation. This paper investigates an IMU-barometer integration for estimation of vertical position (as well as vertical velocity). In particular, a new two-step Kalman/complementary filter is proposed for accurate and efficient estimation using 6-axis IMU and barometer signals. The two-step filter is composed of (i) a Kalman filter that estimates vertical acceleration via tilt orientation of the sensor using the IMU signals and (ii) a complementary filter that estimates vertical position using the barometer signal and the vertical acceleration from the first step. The estimation performance was evaluated against a reference optical motion capture system. In the experimental results, the averaged estimation error of the proposed method was 19.7 cm while that of the raw barometer signal was 43.4 cm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.352-355
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• 2004

The objective of this work is to develop a new design method to find optimal coils, especially the optimal coil configuration of an optical pickup actuator. In designing actuator coils, the developed Lorenz force in the coils along the desired direction should be made as large as possible while forces and torques in other directions should be made as small as possible. The design methodology we are developing is a systematic approach that can generate optimal coil configurations for given permanent magnet configurations. To consider the best coil configuration among all feasible coil configurations, we formulate the design problem as a topology optimization of a coil. The present formulation for coil design is noble in the sense that the existing topology optimization is mainly concerned with the design of yokes and permanent magnets and that the optimization of actuator coils is so far limited within shape or size optimization. Though the present design methodology applies to any problem, the specific design example considered is the design of fine-pattern tracking and focusing coils.

• The Journal of Korean Physical Therapy
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• v.31 no.6
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• pp.368-371
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• 2019

Purpose: The purpose of this study was to investigate the effects of leg length discrepancy on kinematic changes of the pelvis and hip during gait. Methods: A total of ten healthy women with no history of neurological, musculoskeletal surgery or injuries, or pain in the lower limbs were recruited. They were assigned to two groups; the experimental group (LLD) consisting of five subjects leg length discrepancy of 10mm to 18mm and the control group (CON) consisting of five subjects leg length discrepancy of<10 mm. All participants were instructed to perform three walking trials for further analysis by using the Cortex 3.0 software program. Independent T-test and Mann-Whitney test were used to examine the effects of mild LLD on kinematic changes of the pelvis and hip during gait. Results: Angles of hip flexion, hip abduction, pelvic obliquity, and pelvic tilt in the experimental group were not significantly different compared to those of the control group. Conclusion: Mild leg length discrepancy induces kinematic changes in the lower limbs, including decreased hip flexion, increased hip abduction, and increased pelvic obliquity in the shorter limb, and increased hip adduction and increased pelvic obliquity in the longer limb. However, those changes were not significant.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.5
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• pp.40-46
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• 2013

Automatic swing door for an automotive application is considered. The equation of motion for a driver side swing door is introduced and gravity cancellation control scheme is adapted. The control scheme supposed to cancel the moment due to the tilt of the car. A speed control is suggested for door operation automation but the output of the speed control is not suppose to be precise as for the manufacturing system control. In the frame of the velocity control of the door, feedback linearization was applied for collision detection. The collision detection performance is satisfactory. The estimate of the magnitude of disturbance due to the collision is close to the actual magnitude of disturbance. Simulation study has been performed to gain insight into the system behavior. Also real test on the prototype hardware has been performed for verification purpose.

• Journal of Medicine and Life Science
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• v.16 no.3
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• pp.64-75
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• 2019

Vertigo and dizziness are common symptoms with various etiologies and pathogeneses. Vertigo is an illusion of motion due to disease of the vestibular system, usually a sense of rotation. Dizziness, a term that represents a wide range of non-vertigo symptoms, is commonly associated with non-vestibular disorders including old age, cardiac syncope, orthostatic hypotension, metabolic disease, anxiety, and drugs. Vertigo should be determined whether the cause is central or peripheral. Peripheral vertigo is usually benign but central vertigo is serious and often require urgent treatment. The careful history and detailed physical examinations(pattern of nystagmus, ocular tilt reaction, head impulse test and positional tests such as Dix-Hallpike maneuver) provide important clues to the diagnosis of vertigo. Most of patients have benign peripheral vestibular disorders - vestibular neuritis, benign paroxysmal positional vertigo (BPPV), and Meniere's disease. BPPV is a leading cause of peripheral vertigo and can easily be cured with a canalith repositioning maneuver. In this review, a focus is on the differential diagnosis of common vestibular disorders with peripheral and central causes.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.2
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• pp.2065-2070
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• 2020

Background: Weakness of the abdominal and mid thoracic muscles the lead to thoracic kyphosis of stroke patients. The trunk muscles activity of stroke patients is significantly related to upper extremity. Objectives: To investigate the effect of seated exercise of thoracic and abdominal muscles on upper extremity function and trunk muscles activity in stroke patients. Design: One-group pretest-posttest design. Methods: A total of 27 stroke patients were recruited. All stroke patient were given seated abdominal exercise (posterior pelvic tilt exercises) and thoracic exercise (postural-correction exercise). All exercises were conducted for 30 minutes, three times a week for four weeks. The manual function test (MFT) and electromyography (EMG) were measured, and EMG electrodes were attached to thoracic paraspinal muscles and lower rectus abdominal muscles. EMG signal is expressed as %RVC (reference voluntary contraction). Results: Experimental group showed significant increases in abdominal muscles, paraspinal muscles activity and MFT total score, items of arm motion (forward elevation of the upper extremity, lateral elevation of the upper extremity, touch the occiput with the palm) in MFT after four weeks. Conclusion: These results suggest that, in stroke patients, seated exercise of thoracic and abdominal muscles contribute to improve trunk muscles activity and upper extremity function in stroke patients.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.10
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• pp.1986-1991
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• 2007

In this paper, we discussed, intelligent soft filter for MR(magnetoresistive) sensor. Most navigation systems today use some type of compass to determine heading direction. Using the earth's magnetic field, electronic compass based on MR(magnetoresistive) sensors can electrically resolve better then 0.1 degree rotation. Intelligent methode for soft building a one degree compass using MR(magnetoresistive) sensors will also be discussed. Compensation techniques are shown to correct for compass tilt angels and nearby ferrous material disturbances. we proved the fuzzy logic that based on the way the ham deals with inexact information is useful for MR sensors.