• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.59.3-59
• /
• 2001

In this paper, the method of analyzing mobility of the mechanisms is suggested. The method based on the joint screws provides accurate values of mobility of the mechanisms even with the lack of geometric generality. To show its validity, the method is applied to finding mobilities of planar mobile robots and a rough-terrain mobile robot, Mars Rover. To do so, simplified joint model for each of four different typical wheels of the mobile robots are described including friction velocities, firstly. Then, mobility analyses of planar mobile robots and the Mars Rover mobile robot for navigation on the rocky road on Mars are performed. It is confirmed that the obtained results in this study coincide with the previous ones which ...

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.1
• /
• pp.95-103
• /
• 2011

Robots in various types carry and assemble parts through repeatedly and accurately moving to stored locations by combining linear motions. And, linear systems are used in orthogonal axes of robots and driven via ball screws, such as 2-axis cartesian coordinate robot in this paper. This paper presents the effect of the linear motion guide that is used in $2^{nd}$ axis in 2-axis cartesian coordinate robot. Some simulation results show that the linear motion guide influence greatly in robot performance such as the nominal life of linear guide. When use LM guide that have capacity near in $2^{nd}$ axis, this paper show that the nominal life on LM block of $1^{st}$ axis increases 37.4% and that the specification of $2^{nd}$ axis LM guide influences greatly the nominal life of $1^{st}$ axis LM block.

• Journal of Trauma and Injury
• /
• v.32 no.1
• /
• pp.51-59
• /
• 2019

Unstable pelvic ring lesions are usually treated with internal fixation. In patients presenting clinical instability or soft tissue complication risk, external fixation is a safe treatment option. However, pin tract infection, insufficient biomechanical properties, difficulty sitting and changing decubitus are important drawbacks related to the treatment. The present study reports the association of anterior and posterior subcutaneous internal fixation by applying spine-designed implants on the pelvic ring disruption: supra-acetabular pedicle screws with an interconnecting rod (Infix), plus posterior transiliac fixation with the same system, which the authors have named the "Hula Hoop Technique".

• Journal of Trauma and Injury
• /
• v.32 no.1
• /
• pp.60-65
• /
• 2019

Pelvic fractures are associated with life-threatening injuries and high rates of morbidity and mortality. Management of internal blood loss associated with unstable pelvic ring injuries is paramount during the initial period. The reconstruction of the pelvic ring is of importance because it is a major contributor to the stability of the pelvic ring. We report the case of a 25-year-old man who had an unstable pelvic ring fracture combined with rupture of an obturator artery and had a successful and satisfactory treatment using minimally invasive surgery with percutaneous antegrade screw fixation.

• Clinics in Shoulder and Elbow
• /
• v.22 no.2
• /
• pp.106-109
• /
• 2019

Acromial fractures are well-documented complications subsequent to reverse shoulder arthroplasty (RSA), and most appear as stress fractures with no history of single trauma. To date, no study has reported the occurrence of acute displaced acromial fracture due to sudden strong deltoid contraction during heavy work. Displacement of the fracture results in a challenging surgery since it is difficult to obtain adequate fixation in thin and osteoporotic bones. We report a rare case of acute displaced acromial fracture after successful RSA treatment, using a novel technique of open reduction and internal fixation, applying two 4.5 mm cannulated screws and lateral clavicle precontoured plate.

• Clinics in Shoulder and Elbow
• /
• v.24 no.2
• /
• pp.110-113
• /
• 2021

We present an unusual case of bone metastases from renal cell carcinoma around orthopedic implants in a 78-year-old female with osteolytic, expansile, highly vascularized, malignant infiltration around suture anchors in the proximal humerus. The patient had undergone arthroscopic rotator cuff repair using suture anchor implants 6 years previously. After diagnosis of bone metastasis, she was successfully treated with metastasectomy and internal fixation using a plate and screws, with cement augmentation. This report is the first to document metastases around a suture anchor in a bone and suggests the vulnerability of suture anchor implants to tumor metastasis.

• Journal of Korean Dental Science
• /
• v.14 no.1
• /
• pp.40-45
• /
• 2021

During orthodontic treatment of impacted teeth, use of appropriate anchorage against the traction force is important. Tooth anchorage with multi-bracket appliances is commonly used but sometimes it causes unwanted movements of adjacent teeth. Skeletal anchorage devices are therefore considered to minimize such side effects. Still their survival rate and positioning are highly limited according to the bone density and the interradicular space. This case report presents a case of two impacted teeth, one of which is dilacerated and horizontally angulated. Using the microplate with short screws and a bendable neck, negative effects on adjacent teeth were minimized and impacted teeth were repositioned with good stability.

• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.2_1
• /
• pp.169-176
• /
• 2022

Prognostics and health management (PHM) is recently converging throughout the industry, one of the trending issue is to detect abnormal conditions at decanter centrifuge during water treatment facilities. Wastewater treatment operation produces corrosive gas which results failures on attached sensors. This scenario causes frequent sensor replacement and requires highly qualified manager's visual inspection while replacing important parts such as bearings and screws. In this paper, we propose anomaly detection by measuring the vibration of the decanter centrifuge based on the video camera images. Measuring the vibration of the screw decanter by applying the optical flow technique, the amount of movement change of the corresponding pixel is measured and fed into the LST M model. As a result, it is possible to detect the normal/warning/dangerous state based on LSTM classification. In the future work, we aim to gather more abnormal data in order to increase the further accuracy so that it can be utilized in the field of industry.

• Advances in nano research
• /
• v.13 no.3
• /
• pp.247-257
• /
• 2022

Extraordinary properties of nanocomposites make them a primary replacement for many conventional materials. Anterior cruciate ligament (ACL) reconstruction, which is a frequent surgery in sport activities, is one of the fields in which nanocomposites could be utilized. In the present study, the mechanical properties of different porous scaffolds made from graphene nano-composites are presented ad load bearing capacity of these materials is calculated using finite element method. The numerical results are further compared with experimental published data. In addition, several geometrical and material parameters are analyzed to find the best configuration of nanocomposite scaffolds in reconstruction of ACL. Moreover, coating of detoxification chemicals are extremely easier on the nano-structured materials than conventional one. Detoxification potential of nano-composites in the injured body are also discussed in detail. The results indicated that nano-composite could be successfully used in place of auto- and allografts and also instead of conventional metallic screws in reconstruction of ACL.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.4_1
• /
• pp.545-551
• /
• 2023

In this paper, a robot automation methodology for chemical drum assembly in semiconductor industries are presented. Robot automation is essential to resolve safety issues in which operators are directly or indirectly exposed to chemicals or fumes in assembling dispense heads on chemical drums. However, the chemical drum assembling process involves complex and difficult tasks, such as mating male/female keycodes and fastening screws with large-diameter, which may be very difficult to be performed by a single-arm robot with a commercial rigid F/T sensor. In order to solve the problems, a method for assembling a chemical drum using dual-arm collaborative robot system, compliance F/T sensor, robot vision and gripper is presented.