• 한국정밀공학회지
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• 제26권10호
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• pp.56-64
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• 2009

This paper presents a parallel typed walking robot which can walk in omni-direction and climb from a floor to a wall. We design a six D.O.F leg mechanism composed of three legs, which form a parallel mechanism with a base and a ground to generate arbitrary poses. Optimal design is conducted to maximize the walking space and the dexterity, which are normalized by the stroke of leg. Kinematic parameters are found to maximize the weighted optimal objectives. We design a triple parallel mechanism robot by inserting Stewart platform between the upper leg mechanism and the lower leg mechanism and examine the gaits when the robot walks on the ground and climbs from a floor to a wall. The analysis of walking space and dexterity for each gait shows that the triple parallel walking robot has a large walking space with a large stability region. We explore the possibility that the robot can climb from a floor to a wall. Investigating the gaits for the six steps proves that the robot can lift the foot up to the wall by combining the orientational walking space generated by three parallel mechanisms.

• 로봇학회논문지
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• 제12권4호
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• pp.395-401
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• 2017

In this paper, we introduce a robot-assisted medical diagnostic system that enables remote ultrasound (US) imaging to be applied to the conventional telemedicine, which has been possible only with interviewing or a visual exam. In particular, a master-slave robot system is developed that ultrasonic diagnosis specialist can control the position and orientation of US probe in the remote place. The slave robot is designed to be compact, lightweight, and hand-held so that it can easily transfer to the remote healthcare center. Moreover, 6-degree-of-freedom (DOF) probe motion is possible by the robot design based on Stewart platform. The master device is also based on a similar structure of the slave robot. To connect master and slave system in the wide area network (WAN) environment, a hardware CODEC was developed. In this paper, we introduce the detail of each component and the results of the recent experiments conducted in the remote sites by the developed robotic ultrasound imaging system.

• 제어로봇시스템학회논문지
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• 제6권9호
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• pp.796-802
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• 2000

A master-slave system for teleoperation is usually used to control the robor's motion on remote place such as abyss, outer space etc.. When the slave robot is a humanoid one, it can make a better performance if the configuration of the master arm is similar to that of the slave arm and of the human. The master arm proposed in this paper has a type to be put on the human arm, that is, the exoskeleton type, and has a combination of serial joint and parallel mechanism imitating the human's arm structure of muscles and bones, so called hybrid mechanism so that it can follow arm's movement effectively. But it is easy to solve the forward kinematis of the parallel structure because relating equations are implicit functions. In order to solve that, the virtual joint angle corresponding to human arm's joint is introduced and a sequential computation step is employed in calculating virtual joint angles and the posture of the end effector. Also validity is checked up through computational simulation.

• 한국광학회지
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• 제18권2호
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• pp.130-134
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• 2007

광역의 자유곡면 형상을 나노미터 정밀도로 측정하기 위한 새로운 형상 측정법으로서 곡률에 근거한 형상 측정법을 제안한다. 곡률 형상 측정기는 피측정물을 일정간격으로 스캔하는 간섭계로써 각 국부영역의 형상으로부터 곡률을 획득하여, 이로부터 전 영역의 형상을 복원한다. 제안된 곡률 형상 측정기는 비구면 형상 측정을 위해 개발된 보상 광학계(Null optics)나 국부영역의 형상을 측정하고 결합하는 subaperture-slicking 법에 비해 측정 장비로부터 발생하는 시스템 오차를 근본적으로 제거하는 특징을 가진다. $80mm\times80mm\times25mm$ 작동구간을 갖는 Stewart Platform과 상용 트와이만 그린 간섭계를 이용하여 곡률간섭계를 구성하였으며, 자유곡면의 형상측정을 위한 첫 단계로서 잘 알려진 구면형상을 측정하고, 기존 장비의 측정값과 비교한 결과 32 mm영역에서 최대 56 nm의 차를 보임을 확인하였다.

• 제어로봇시스템학회논문지
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• 제9권8호
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• pp.577-584
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• 2003

Traditional ankle rehabilitation procedures are tedious, repetitive, and require therapist's help. Therefore, they do not provide patients with good motivation to actively participate in the rehabilitation exercises. In addition, objective diagnosis and evaluation of the treatment progress have been difficult because records of exercise history are made by passive instruments from time to time. The virtual reality technology can make these procedures more fun so that patients can perform everyday rehabilitation exercises more actively. Moreover, haptics technology can give active resistance to the patients ankle motion to improve strength of muscles as well as can record ankle's motion and force histories for objective diagnosis and evaluation. This paper summarizes development of a virtual environment fur reforming the conventional ankle rehabilitation procedures. First of all, conventional rehabilitation procedures have been summarized. Secondly, haptic design and control, user interface design, virtual environment contents design are described. Lastly, mutual cooperation among many developers including medical doctors and therapists and future works are commented.

• Structural Engineering and Mechanics
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• 제49권5호
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• pp.645-660
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• 2014

This paper presents the design and project of an innovative concept for a Single Point Incremental Forming (SPIF) Machine. Nowadays, equipment currently available for conducting SPIF result mostly from the adaptation of conventional CNC machine tools that results in a limited range of applications in terms of materials and geometries. There is also a limited market supply of equipment dedicated to Incremental Sheet Forming (ISF), that are costly considering low batches, making it unattractive for industry. Other factors impairing a quicker spread of SPIF are large forming times and poor geometrical accuracy of parts. The following sections will depict the development of a new equipment, designed to overcome some of the limitations of machines currently used, allowing the development of a sounding basis for further studies on the particular features of this process. The equipment here described possesses six-degrees-of freedom for the tool, for the sake of improved flexibility in terms of achievable tool-paths and an extra stiffness provided by a parallel kinematics scheme. A brief state of the art about the existing SPIF machines is provided to support the project's guidelines.

• 한국의학물리학회지:의학물리
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• 제28권4호
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• pp.171-180
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• 2017

The purpose of this study is to install a system that compensated for the respiration motion using an articulated robotic manipulator couch which enables a wide range of motions that a Stewart platform cannot provide and to evaluate the performance of various prediction algorithms including proposed algorithm. For that purpose, we built a miniature couch tracking system comprising an articulated robotic manipulator, 3D optical tracking system, a phantom that mimicked respiratory motion, and control software. We performed simulations and experiments using respiratory data of 12 patients to investigate the feasibility of the system and various prediction algorithms, namely linear extrapolation (LE) and double exponential smoothing (ES2) with averaging methods. We confirmed that prediction algorithms worked well during simulation and experiment, with the ES2-averaging algorithm showing the best results. The simulation study showed 43% average and 49% maximum improvement ratios with the ES2-averaging algorithm, and the experimental study with the $QUASAR^{TM}$ phantom showed 51% average and 56% maximum improvement ratios with this algorithm. Our results suggest that the articulated robotic manipulator couch system with the ES2-averaging prediction algorithm can be widely used in the field of radiation therapy, providing a highly efficient and utilizable technology that can enhance the therapeutic effect and improve safety through a noninvasive approach.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.520-525
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• 2011

As worldwide concern stands on global warming and greenhouse gases from internal combustion engine, the interests in technologies for a highly efficient powertrain has been increased. Concurrently the investigation to improve the deteriorated NVH, a by-product of energy efficient powertrain, is conducted seriously. The NVH performance of a new type of active engine mount that offers increased advantages over a passive hydraulic mount is examined using a newly developed 6-DOF simulator. The simulator is in the shape of Hexapod Stewart Platform adopting LEMA, a new type of actuator which is patented and commercialized by ACT Inc,, the world wide leader in the design, development, and manufacture of high performance linear electro-magnetic actuators for active vibration control. The target vibration signals of an aimed vehicle at four engine mounts are measured and simulated by 6-DOF simulator at the laboratory. The resulting NVH performances of the new active mounting system at a vehicle and on a simulator are examined and compared. Even though the active mount performance of lab test demonstrates less effective than the result of a real vehicle test, vibration reduction is identified through the simulator.

• 한국생산제조학회지
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• 제25권6호
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• pp.517-521
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• 2016

General industrial robots are difficult to use for precision assembly because they are operated based on position control. Their position accuracy is also usually higher than the assembly clearance (several tens of ${\mu}m$). In previous researches, force control was suggested as a robotic assembly solution. However, this method is difficult to apply in reality because of speed and cost problems. The RCC provides high speed, but applications are limited because the compliance is fixed, and it cannot detect an assembly condition during a task. A variable passive compliance device (VPCD) was developed herein. The VPCD can detect the assembly condition during tasks. This device can provide proper compliance for successful assembly tasks. The pneumatic system and the Stewart platform with an LVDT sensor were applied for measuring the displacement and variable compliance, respectively. The concept design and analysis were conducted to prove the effectiveness of the developed VPCD.

• 대한의용생체공학회:의공학회지
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• 제25권6호
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• pp.505-510
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• 2004

본 논문에서 우리는 6자유도 원형 체외고정기의 조정을 위한 자동화 시스템에 관한 연구를 진행하였다. 6자유도 원형체외 고정기 자동화시스템은 HCF(Hexapod Circular Fixaotr)라는 체외 고정기를 자동화 한 것으로 HCF의 조정을 위한 소프트웨어와 HCF의 스트럿을 조정해주는 자동화 스트럿으로 구성된다. HCF는 일리자로프 고정기의 한 형태로서, 대표적인 병렬형 로봇인 스튜어트 플랫폼과 유사한 기구적 구조를 갖는다. HCF 조정 소프트웨어는 복잡한 골 변형의 교정을 쉽게 하기위한 소프트웨어로서, X-ray 사진을 이용하여 데이터를 획득한 후, 이 데이터를 HCF 조정 소프트웨어에 입력하여 스트럿의 길이 조정 값을 구한다. 또한 여기서 구한 스트럿 길이 조정 값을 자동화 스트럿 컨트롤러로 입력하여, 자동화 스트럿은 계획된 위치만큼 자동으로 구동된다. 또한 HCF 조정 소프트웨어 데이터는 자동화 스트럿 없이 일반 스트럿을 이용하여 HCF 조정을 위해 사용될 수 있다. 제안된 시스템은 실험을 통하여 그 타당성을 검증하였다.