• Proceedings of the KSME Conference
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• 2004.11a
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• pp.567-572
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• 2004

In this research, a stable walking pattern generation method for a biped robot is presented. A biped robot is considered as constrained multibody system by several kinematic joints. The proposed method is based on the optimized polynomial approximation of the trunk motion along the moving direction. Foot motions can be designed according to the ground condition and walking speed. To minimize the deviation from the desired ZMP, the trunk motion is generated by the fifth order polynomial approximation. Walking simulation for a virtual biped robot is performed to demonstrate the effectiveness and validity of the proposed method. The method can be applied to the biped robot for stable walking pattern generation.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1272-1277
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• 2005

In this study, we wolud be developed the fuzzy controlled PGO that controlled the flexion and the extension of each PGO's joint using the bio-signal and FSR sensor. The PGO driving system is to couple the right and left sides of the orthosis by specially designed hip joints and pelvic section. This driving system consists of the orthosis, sensor, control system. An air supply system of muscle is composed of an air compressor, 2-way solenoid valve(MAC, USA), accumulator, pressure sensor. Role of this system provide air muscle with the compressed air at hip joint constantly. According to output signal of EMG sensor and foot sensor, air muscles and assists the flexion of hip joint during PGO gait.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.375-377
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• 2009

This paper researched the algorithm of robot's walking and action on the basis of robot studied and made at our laboratory and studied how to efficiently control the robot joints by developing wireless Digital Servo Motor using Zigbee Sensor Network Module which is using at wide part recently. I realized the stable walking by adopt Press Sensor at the bottom of robot foot to get stability of walking. Also I let the algorithm calculate the robot movement to make the joint motion and monitored the robot walk to its motion. At this Paper, I studied the method organizing the motion by the each robot walking and measuring the torque applying to the joint. And I also knew that it is possible to make its control and construct hardware more conveniently than them of the existing studied and controling 2Legs Walking Robot by applying it at walking robot and developing wireless servo motor by Zirbee Sensor Network.

• Proceedings of the ESK Conference
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• 1994.04a
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• pp.136-144
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• 1994

In this study, the human gait trajectories during normal walking were synthesized using the inverse kinematics and optimization techniques. The synthesis based on a lower extremity model consisting of a torso and two legs. Each leg has three segments: thigh, shank, foot, and is assumed to move with six degrees-of-freedom. In order to synthesize trajectiories of this redundant system, the sum of angular displacements of articulating joints was selected as an objective function to be minimized. The proposed algorithm in this study is very useful for the analysis of human gait. For the gait analysis, the trajectories of four points in each leg should be measured. However, by using the algorithm, measuring the trajectories of two points is sufficient, and thus the experimental set-up can be simplified. The predicted joint trajectories showed a good agreement with those obtained from the experiment. The statistical analysis and graphic simula- tions are also presented.

• Journal of Korean Foot and Ankle Society
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• v.11 no.2
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• pp.232-237
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• 2007

Introduction: To report the result of the thigh perforator free flap for the reconstruction of the soft tissue defect of the lower extremities and usefulness of this flap. Materials and Methods: We have performed 23 cases of thigh perforator free flap to reconstruct the soft tissue defect of the lower extremities between February 2004 and July 2005. The anterior aspect of the legs were 9 cases, the ankle joints were 4 cases, the dorsal aspect of the feet were 6 cases, the sole of the feet were 4 cases as recipient sites. The anterolateral thighs were 13 cases, the anteromedial thighs were 10 cases as donor sites. The size of the flap ranged from $4{\times}5\;cm$ to $12{\times}18\;cm$. The mean flap area was $73.2\;cm^2$. The length of the pedicle ranged from 5 cm to 15 cm. Every patient except children was operated under the spinal anesthesia. Results: 21 flaps (91.3%) survived, 2 flaps (8.7%) failed. In the 21 flaps that had survived, there were partial necrosis in 4 cases, which healed without any additional operation. In the 13 anterolateral thigh perforator flaps, 9 cases survived totally, 3 cases had the partial necrosis, 1 case failed. In the 10 anteromedial thigh perforator flaps, 8 cases survived totally, 1 case had the partial necrosis, 1 case failed. Conclusion: The authors had a good result with the thigh perforator free flap and believe that this flap is a good option for the reconstruction of the soft tissue defect of the lower extremities, because this flap has a thin thickness and it is easy to dissect the vessels. Moreover the patients can be operated with supine position.

• Journal of Korean Foot and Ankle Society
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• v.12 no.1
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• pp.66-73
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• 2008

Purpose: To report the clinical results of tibio-talo-calcaneal arthrodesis fixed with multiple cannulated screws for the cases of painful ankle and hindfoot arthropathy regardless of any deformity or instability. Materials and Methods: A retrospective analysis was performed upon 10 patients that underwent tibio-talo-calcaneal arthrodesis from October 1999 to May 2006. There were 4 males and 6 females, with an average age of 63 years (43-70). The etioloty of arthrodesis included 5 osteoarthritis, 2 Charcot joints, 1 rheumatoid arthritis, 1 Tbc arthritis and 1 residual poliomyelitis. Chief complaints were pain in 9 cases and instability in 1 case. Three patients had combined severe varus deformity. Tibio-talo-calcaneal arthrodesis using multiple cannulated screws was performed by transfibular approach for all cases and short leg cast was applied for 12 weeks postoperatively. Results: The average follow-up period was 16.5 months (12-26 months). VAS pain score was average 8.2 (7-10) and modified AOFAS score was average 25 (8-40, total 86) preoperatively. At final follow-up, VAS score was average 1.0 (0-3) and AOFAS score improved to average 66 (58-75). There were 4 complications: 2 nonunion, 1 tibia stress fracture and 1 malunion. Seven of 8 patients were satisfied with the results at final follow-up. Conclusion: Fixation with multiple cannulated screws for tibio-talo-calcaneal arthrodesis through transfibular approach is a recommendable surgical option.

• Journal of Korean Foot and Ankle Society
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• v.14 no.2
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• pp.146-150
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• 2010

Purpose: Pilon fracture has several serious complications such as joint stiffness, arthrosis and delayed angular deformity. We report short-term results of new treatment modality using distracted dynamic external fixators and early controlled ankle motion. Materials and Methods: Eight cases of severe pilon fractures for which we tried small plate fixation and additional distracted dynamic external fixators from July 2007 to June 2009 were included. Half passive continuous ankle joint motion was allowed under free hinged ring fixators after the operation. The external fixators were removed after two or three months from the surgery. We investigated joint space by radiograph, joint pain, range of motion, patient's satisfaction of treatment protocol. Results: Joints were distracted when external fixators were applied and mean 28% of space loss developed after removal of external fixators. In most of cases, satisfactory alignments were maintained. Regarding range of joint motion, mean dorsiflexion angle was 15 degrees and mean plantarflexion angle was 32 degree in the condition of wearing external fixators. There was mean 8% reduction of range of motion but no further progression of ankle stiffness after removal of external fixators. Dorsiflexion was not improved after that, but plantarflexion angle was improved 10% even after removal of external fixators. Patients were generally in compliance with the treatment protocols with high level of satisfaction. Conclusion: We got good results with distracted dynamic external fixators and early continuous half-passive joint motion for pilon fractures in terms of joint pain and range of motion. Therefore we suggest this new protocol as an alternative modality for severe pilon fractures.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.239-246
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• 2018

In this study, we analyzed the balance of the both legs and the kinematic analysis of the upper limb segments and joints during archery shooting and compared the differences according to the scores. 9 K-university elite archery athletes participated. Each archer was asked to shoot 3-shots and 5-ends on a 122 cm target at a distance of 70 m. Seven infrared cameras (Qualisys, sweden) and two force plates (Kistler, Switerland) were used to calculate the upper limb segments and joint movements and the center of pressure (COP). When the archers shot 8 points, range of motion of elbow joint angle on drawing-arm and mediolateral COP range of motion on the left foot were larger than when 9-10 points were shot (p<.05). In order to maintain a high score in the archery game, constant balance is required, and the balance of the left foot supporting the bow during the shooting is an important factor. In addition, minimizing elbow joint movement of the drawing-arm supporting the bow will help stabilized shooting.

• Journal of Korean Foot and Ankle Society
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• v.1 no.2
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• pp.112-118
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• 1997

Tarsometatarsal fracture-dislocation is uncommon but severe lesion. Since this lesion is sometimes difficult to recognize by roentgenography, it is easily overlooked. Three patients were treated with open reduction and internal fixation with 3.5 mm cannulated screw and K-wire, two had treatment with open reduction and internal fixation with 3.5 mm cannulated screw only and two had treatment with dosed reduction and short leg cast only between January 1994 and May 1996. The duration of follow-up ranged from twelve to twenty-nine months after the diagnosis. Results were assessed by a subjective questiormaire, physical examination, and radiographic analysis. Multiple fixation techniques for maintaining the reduction of tarsometatarsl joint have been introduced. We recent]y used the 3.5 mm cannulated screw for internal fixation of the tarso-first and second metatarsal fracture-dislocation. We think cannulated screw fixation has several advantages; 1. The cannulated screw fixation is more rigid than the K-wire fixation. 2. There is an decreased risk of screw breakage with early weight bearing. 3. It is possible to compress the involved joints, if necessary. There were no disability in all patients. One patient who was treated with delayed open reduction and internal fixation with 3.5 mm cannulated screw and K-wire had a radiographic mild degenerative arthritis. And one patient who was treated with dosed reduction and short leg cast had a mild metatarsus adductus. But. these two patients were symptom free. There was no correlation between the severity of the diastasis and the patient s functional result.

• Journal of Korean Foot and Ankle Society
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• v.1 no.2
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• pp.89-94
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• 1997

The functional disabilities post arthrodesis of the ankle include difficulty in climbing inclined surface, such as hill, ramps, or stair even through without pain. There will be periankle joints arthrosis as time passes. Total ankle replacement permits remobilization, no need for prolonged immobilization. There will be no increas in the mechanical stress of the neiboring joint. Total ankle replacement has been proposed as an alternative to arthrodesis in the management of painful arthrosis of the tibiotalar joint recently. We performed 7 cases of replacement from 1990. 4. 1 to 1996. 7. 1 with 2-3 years follow up. A retrospective review was undertaken for 7 patients with the arthrosis of tibiotatar joint. The results were as following. 1. The clinical results according to the point system for ankle study evaluation were excellent in 2 cases, good in 4 cases, and fair 1 case. 2. The improvement was especially obvious in terms of pain and functional recovery. 3. Total ankle replacement especially unconstrained type seems quite good alternative to arthrodesis.