• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.3
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• pp.202-207
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• 2013

In the paper, we design a autonomous mobile robot for freight transportation and propose an operation method of the robot in the warehouse. In order to implement autonomous navigation, it is needed to recognize the position of the robot and track the path to the target. Previous methods are hard to change the workspace environment and need high cost to install and keep a maintenance of the system. The lifter of freight transportation robot is designed to load and unload a baggage through up and down motion. Also, ultrasonic sensor, RFID, QR-code and camera sensor is used to carry out various functions while the robot navigates in the various environment. We design an operation method of the mobile robot in order to effectively arrive a goal position and transport a freight. The proposed methods are verified through various experiments.

• Journal of Society of Preventive Korean Medicine
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• v.18 no.2
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• pp.115-123
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• 2014

Objective : The objective of this study is to develop a Qigong exercise program to reinforce musculoskeletal system of seniors appropriate for physical strength and conditions of seniors aged 65 years or above based on health Qigong exercise of oriental medicine. Method : Qigong exercise motions that can improve strength, muscular endurance, flexibility, and cardiovascular endurance of seniors were developed by primarily performing literature review of Qigong experts on the fields like oriental medicine, Qigong exercise, physical education and health science and secondarily using motion training for increased validity of motions. Results : The Qigong exercise program for musculoskeletal system of seniors was designed with 12 motions repeated 8 times and 20 minutes per session, including shoulder exercises (alternate turning of left and right shoulders, turning both arms back and forth, holding and lifting elbow to put it aside), waist exercises (wrapping the head with hands to bow, twisting waist while looking at the tip of hand, large spinning of ball, putting hands together to pull back), and knee exercises (going up a down while lifting a rock, balancing the body while lifting a knee, lifting and spreading knees while drawing circle with arms, raising both arms to the side while lifting heels, breathing). Conclusion : Once the effects of Qigong exercise for musculoskeletal system of seniors developed in this study are tested, the program is expected to contribute to development of Qigong exercise, a core part of oriental medicine health improvement project.

• Journal of Korean Foot and Ankle Society
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• v.14 no.2
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• pp.109-114
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• 2010

Purpose: The purpose of this study was to report the surgical outcome of reconstruction of neglected chronic Achilles tendon ruptures with various methods including Achilles tendon allograft. Materials and Methods: Between October 2003 and November 2008, 8 consecutive neglected chronic Achilles tendon ruptures with the defect gap of more than 4 cm underwent surgical reconstruction including V-Y advancement, gastrocnemius fascial turn-down flap, flexor hallucis longus transfer and Achilles tendon allograft. There were 7 males and 1 female who were evaluated at more than 18 months after surgery. At the time of followup, all patients were assessed with regard to postoperative complications, their self-reported level of satisfaction, the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale, 10 repetitive single heel rise, single leg hopping test, and ankle range of motion. Results: The AOFAS score increased from average 71.4 (50-87) to 96.4 (86-100). All patients were able to perform 10-repetitive single heel raise and single leg hopping at the latest follow up. No patient experienced wound complications and deep infection. Six patients were rated as 'excellent' and the other two as 'good'. Conclusion: Neglected chronic Achilles tendon ruptures could be successfully treated with careful selection of the reconstruction method according to the amount of defect gap. With an extensive defect, Achilles tendon allograft can be a good option when the reconstruction is not feasible otherwise.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.5
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• pp.487-495
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• 2012

In this paper, a Smart Home Service Robot, McBot II, which performs mess-cleanup function etc. in house, is designed much more optimally than other service robots. It is newly developed in much more practical system than McBot I which we had developed two years ago. One characteristic attribute of mobile platforms equipped with a set of dependent wheels is their omni- directionality and the ability to realize complex translational and rotational trajectories for agile navigation in door. An accurate coordination of steering angle and spinning rate of each wheel is necessary for a consistent motion. This paper develops trajectory controller of 3-wheels omni-directional mobile robot using fuzzy azimuth estimator. A specialized anthropomorphic robot manipulator which can be attached to the housemaid robot McBot II, is developed in this paper. This built-in type manipulator consists of both arms with 4 DOF (Degree of Freedom) each and both hands with 3 DOF each. The robotic arm is optimally designed to satisfy both the minimum mechanical size and the maximum workspace. Minimum mass and length are required for the built-in cooperated-arms system. But that makes the workspace so small. This paper proposes optimal design method to overcome the problem by using neck joint to move the arms horizontally forward/backward and waist joint to move them vertically up/down. The robotic hand, which has two fingers and a thumb, is also optimally designed in task-based concept. Finally, the good performance of the developed McBot II is confirmed through live tests of the mess-cleanup task.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.11
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• pp.943-950
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• 2016

The purpose of this study was to evaluate and compare by finite element analysis the biomechanical performance, in terms of cervical stand-alone cage screw insert angle (Type 3 - 5: 2 Screws) and screw arrangement (Type 6 and 7: 3 Screws / Type 8 and 9: 4 Screws), and the range of motion (ROM) of traditional anterior cervical discectomy of a fusion device (Type 1: Cage / Type 2: Cage + ACP). Our study suggests that the biomechanical behavior of a postoperative cervical spine could indeed be influenced by design features, such as screw angle and number of screws. In particular, ROM and the risk of subsidence were more sensitive during extension about type 5 (Insert Angle $20^{\circ}$). Our study also suggested that the number of screw asymmetries between up and down for type 6 and 7 could result in differences in the risk of screw fracture manifesting in different clinical aspects.

• Physical Therapy Korea
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• v.13 no.1
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• pp.24-31
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• 2006

The purpose of this study was to identify the effect of the hip internal rotation on gluteal and erector spinae muscle electromyographic (EMG) activity during treadmill walking. Eleven healthy subjects were recruited. All subjects performed treadmill walking while maintaining the hip in neutral position (condition 1) and in internal rotation (condition 2). Surface EMG activity was recorded from four muscles (gluteus maximus (GM), gluteus medius (GMED), tensor fascia latae (TFL), and erector spinae (ES)) and the hip internal rotation angle was measured using a three dimensional motion analysis system. The gait cycle was determined with two foot switches, and stance phase was normalized as 100% stance phase (SP) for each condition using the MatLab 7.0 program. The normalized EMG activities according to the hip rotation (neutral or internal rotation) were compared using a paired t-test. During the entire SP of treadmill walking, the EMG activities of GM in condition 1 were significantly greater than in condition 2 (p<.05). The EMG activities of TFL and ES in condition 2 were significantly greater than in condition 1 (p<.05). The EMG activities of the GMED in condition 1 were significantly greater than in condition 1 (p>.05) except for 80~100% SP. Further studies need randomized control trials regarding the effect of hip internal rotation on the hip and lumbar spine muscle activity. Kinetic variables during gait or going up and down stairs are also needed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.8
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• pp.1250-1258
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• 1997

This paper reports on the development of a new foot for a quadrupedal jointed-leg type walking robot. The foot has 2 toes, one at the front and the other at the rear side, for stable landing on uneven ground by point contact. The toes can move up and down independantly, guided by double-wishbone shaped parallel links which enable the lower leg to rotate with respect to a remote center on the ground surface. The motion of each toe is damped by a hydropneumatic shock absorber integrated in the foot in order to absorb the dynamic landing shock. Furthermore, the new foot can reduce the maximum hip joint drive torque by shortening the moment arm length between the hip joint and the landing force vector on the ground. Intensive experiments were carried out in this study by using a one-leg walking model to investigate the soft landing performance of the foot which could be hardly offered by conventional robot feet such as a flat plate with a gimbal type ankle joint. And it was confirmed that the hip joint torque of the leg walking on the flat surface could be reduced remarkably by using the new foot.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.6
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• pp.448-453
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• 2023

As the production of small quadcopter drones has diversified and multi-sensors have been installed in FC due to the spread of MCU capable of high-speed processing, small drones that can perform special-purpose operations rather than simple operations have been realized. Hovering, attitude control, and position movement control were possible through the IMU in the FC mounted on the drone, but control is not easy when GPS connection and video communication are not possible in a closed building with a complex structure. In this study, when encountering an obstacle with a change in altitude in such a space, we proposed a method to overcome the obstacle and perform autonomous flight using optical flow and IR sensors using the Lucas-Kanade method. Through experiments, the drone's altitude flight on stairs that replace the complex structure of a closed space with stable hovering motion has a success rate of 98% within the tolerance of 10 [cm] due to external influences, and reliable autonomous flight up and down is achieved.

• Journal of Korea Game Society
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• v.12 no.1
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• pp.67-77
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• 2012

With the development of tangible interface in recent years, the interest in interactive exercise games to improve health-related physical fitness has been increased. We believe that this kind of serious game should provide not only motion sensing of the action required to play sports but also a specific effectiveness of exercise. This paper will show how a serious exercise game affects theirs heart rate and preference. For the experiments, we used an exercise game named GalaxyBike for aerobics exercise which is developed by the Interaction Media Research Center of Hoseo University. In the experiments, players' heart rate was measured during the warming-up, exercise and cooling-down periods by a wireless heart-rate measuring instrument. After they played the exercise game, a survey was conducted to see how they like this serious exercise game. The findings of the study suggest that the serious exercise game providing both video game and exercise would make a contribution to the improvement of health-related physical fitness since it serves to increase the heart rate and motivation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.11
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• pp.74-79
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• 2021

Generally, multi-legged walking robots have excellent mobility in rough and uneven terrain, and they are deployed for the safety of rescuers in various disaster environments. However, as each leg is driven by a number of actuators, it leads to a complicated structure and high power consumption; therefore, it is difficult to put them into practical use. In this article, a new concept is proposed of a walking robot whose legs are driven by a complex linkage structure to overcome the deficiencies of conventional multi-legged walking robots. A double crank-rocker mechanism is proposed, making it possible for one DC motor to actuate the left and right movements of two neighboring thighs of the multi-legged walking robot. Each leg can also move up and down through an improved cam structure. Finally, each mechanism is connected by spur and bevel gears, so that only two DC motors can drive all legs of the walking robot. The feasibility of the designed complex linkage mechanism was verified using the UG NX program. It was confirmed through actual production that the proposed multi-legged walking robot performs the desired motion.