• 한국정밀공학회지
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• 제15권11호
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• pp.100-107
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• 1998

This paper presents the development of estimation model and control method based on the new robot vision. This proposed control method is accomplished using the sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on the model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters, depending on each camera the joint angle of robot is estimated by the iteration method. The method is experimentally tested in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.1114-1119
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• 1995

This paper presents the development of estimation model and control method based on the new computer vision. This proposed control method is accomplished using a sequential estimation scheme that permits placement of the rigid body in each of the two-dimensional image planes of monitoring cameras. Estimation model with six parameters is developed based on a model that generalizes known 4-axis scara robot kinematics to accommodate unknown relative camera position and orientation, etc. Based on the estimated parameters,depending on each camers the joint angle of robot is estimated by the iteration method. The method is tested experimentally in two ways, the estimation model test and a three-dimensional rigid body placement task. Three results show that control scheme used is precise and robust. This feature can open the door to a range of application of multi-axis robot such as assembly and welding.

• 한국정밀공학회지
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• 제13권11호
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• pp.132-142
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• 1996

This paper presents a technique to model and control a manipulator which has a flexible link and moves in a vertical plane. The flexible link is modeled as an Euler-Bernoulli Beam. Elastic deformation of the flexible link is represented using the assumed modes method. A comparison function which satisfies all geometric and natural boundary conditions of a cantilever beam with an end mass is used as an assumed mode shape. Lagrange's equation is utilized for the development of a discretized model. This paper presents a simple technique to improve the correctness of the developed model. The final model including the shortening effect due to elastic deformation correlates very well with experimental results. The free body motion simulation shows that two assumed modes for the representation of the elastic deformation is proper in terms of the model size and correctness. A control algorithm is developed using PID control technique. The proportional, integral and derivative control gains are determined based on dominant pole placement method with a rigid one-link manipulator. A position control simulation shows that the control algorithm can be used to control the position and residual oscillation of the flexible one-link manipulator effectively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제36권4호
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• pp.320-324
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• 2010

Introduction: The placement of a single miniplate is not sufficient to achieve rigid fixation in mandibular angle fractures. It often causes difficulties in reducing the intermaxillary fixation (IMF) period. Consequently, the placement of 2 miniplates is preferable. The intraoral approach in an open reduction and internal fixation (ORIF) of a mandibular angle fracture with 2 miniplates is often challenging. Accordingly, an alternative of transbuccal approach is performed. However, this method leaves a scar on the face and can result in facial nerve injury. This clinical study suggests a protocol that can maintain rigid fixation without a transbuccal approach in mandibular angle fractures. Materials and Methods: The subjects were 7 patients who sustained fractures of the mandibular angle and treated at Department of Oral and maxillofacial surgery, Sacred Heart Hospital, Hallym University. ORIF under general anesthesia was done using the intraoral approach. One miniplate was inserted on external oblique ridge of the mandible, and the other was placed on lateral surface of the mandibular body with contra-angle drill and driver. A radiographic assessment and occlusal contact point examination was carried out before surgery, and 2, 4 and 6 weeks after surgery. Results: The mean operation time was 80 minutes. Regarding the occlusion state, the number of contact points increased after surgery. Paresthesia and infection were reported to be complications before surgery. Conclusion: The placement of 2 miniplates using contra-angle drill for ORIF of mandibular angle fractures allows early movement of the mandible without IMF. We propose this approach to reduce the patients’discomfort and simplify the surgical procedure.

• 구강회복응용과학지
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• 제25권4호
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• pp.391-401
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• 2009

임플란트의 성공은 식립 후의 초기 안정성 (Initial stability)의 결과가 중요한 영향을 준다. 이 연구의 목적은 연질 골에서 두 종류의 테이퍼 형태 임플란트가 임플란트의 디자인과 self-tapping blade의 유무에 따라서 초기 안정성에 주는 영향을 알아보는 것이다. Self-tapping blade를 가지고 있는 것과 가지고 있지 않은 두 종류의 테이퍼 형태 임플란트가 사용되었다. Solid Rigid Polyurethane Form으로 연질 골 상태인 D4 골 모형을 재현하였다. 임플란트 고정체를 식립하면서 초기 안정성 값을 기록하고, 식립 직후 implant stability quotient (ISQ)을 측정하여 Resonance frequency Analysis (RFA)를 평가하였다. 마지막으로 임플란트가 식립된 모형골을 만능 시험기에 부착하여 장축 방향으로의 pull-out force를 측정하였다. 초기 안정성 값과 최대 pull-out torque 값은 non self-tapping implants가 self-tapping group에 비하여 통계학적으로 유의하게 큰 평균값을 나타냈다 (P = 0.008). 공진 주파수 분석 결과인 ISQ 값은 거의 비슷한 평균값을 보였으면 통계학적으로 차이가 없었다. 각 임플란트 시스템에서 식립 토크와 pull-out 최대 토크 그리고 공진 주파수 간에는 상관관계를 나타내지 않았다. Non self-tapping 임플란트의 높은 식립 토크는 임상적으로 우수한 초기 안정성을 의미한다. 결론적으로 연질 골에서 self-tapping blade가 없는 임플란트가 있는 것 보다 더 우수한 초기 안정성을 보였다.