• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.795-800
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• 2000

In a parallel manipulator, there are three constraints that determine workspace: link length constraint, passive joint angle constraint, and interference among links. Generally, the link length constraint is the most dominant. The interference among links is, however, also an important parameter in designing a desired parallel manipulator. In this study, the interference among links is mathematically modeled by considering the links as a line and a cylinder of radius of twice the link radius, and a new algorithm is suggested to check if arbitrary two links interfere each other or not. The workspace of a cubic parallel manipulator is illustrated in a 2D space satisfying the three constraints.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.893-900
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• 1994

In this study, workspace analysis has been performed for a Clemens Coupling type parallel robotic wrist with four degrees of freedom such as three angular degrees of freedom and 1 plunge motion. Because of plunge motion, this mechanism has no singular point that the general roll-pitch-roll mechanisms have. Also, proposed mechanism performs larger load, faster motion, with less weight and has better structural characteristics such as higher stiffness and strength to weight ratio compared with serial type mechanisms. As a basic step for position control, the closed form solution of forward and inverse kinematics are proposed and workspace is analyzed and plotted by applying triangle tracer method for workspace boundary tracing.

• 제어로봇시스템학회논문지
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• 제4권2호
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• pp.226-234
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• 1998

The concept of dynamic tracking line is proposed as the feasible tracking region for a robot in a robot-conveyor system, which takes the conveyor speed into consideration. This paper presents an effective method to identify the dynamic tracking line in a robotic workcell. The maximum line speed of a robot is derived in an analytic form using the parameterized dynamics and kinematics of the manipulator, and some of its properties are established mathematically. The identification problem of the dynamic tracking line is then formulated as a root-solving problem for a single-variable equation, and solved by using a simple numerical technique. Finally, numerical examples are presented to demonstrate the methodology and its applications in workspace specification.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.951-952
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• 2011

• 한국기계가공학회지
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• 제21권2호
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• pp.116-122
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• 2022

This study proposed a method of testing the stability when selecting gears to reduce the weight of a 3-DOF wrist mechanism for a pick-and-place 3-DOF parallel robot with an increased workspace by using an additional straight axis at its top. We performed SolidWorks^® modeling- and ANSYS^®-based structural analysis of a pinion gear, which is most vulnerable to the force from a 3-DOF wrist mechanism, to lighten the robot weight for performing various tasks. When the initial analysis results considerably differed from the theoretical values calculated in advance, we checked and identified the errors in the contact conditions or input values. Ultimately, it is believed that the methodology presented in this paper will help in mitigating errors during analysis and determine the accurate values for a lightweight 3-DOF wrist mechanism for a parallel robot with an expanded workspace.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.621-625
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• 2005

This paper presents a new hybrid serial-parallel robot(HSPR), which has six degrees of freedom driven by ball screw linear actuators and motored joints. This hybrid robot design presents a compromise between high rigidity of fully parallel manipulators and extended workspace of serial manipulators. The hybrid robot has a large, singularity-free workspace and high stiffness. Therefore, the presented kinematic structure of the hybrid robot is particularly suitable for multi-tasking machining processes such as milling, drilling, deburring and grinding. In addition to the machining processes, the hybrid robot can be used for welding, fixturing, material handling and so on. The study on design of the hybrid robot is performed. A kinematic analysis and mechanism description of the hybrid robot with six-controlled degree of freedom is presented. In the virtual design works by DADS, workspace and force analysis are discussed. A numerical model is treated to demonstrate our analysis and to determine the range of permissible extension of the struts. Also, we determine some important design parameters for the hybrid robot.

• 한국안전학회지
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• 제26권3호
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• pp.75-82
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• 2011

The objective of this study was to identify risk factors associated with the occurrence of musculo-skeletal symptoms of cashiers and provide suggestions for an improved workspace design. Workload and exertion of each task were measured using job analysis and posture analysis. The three most time-consuming tasks were waiting (43.8%), scanning (23.5%) and payment transaction (22.9%). It was analyzed that the workspace can be improved by applying Korean anthropometric data to the design of the desk height. The most common posture was a standing posture with neutral back, and bent lower arms and hands. Finally, it was revealed that 'scanning' and 'payment transaction' seemed more stressful than other operations. The result of the ergonomic evaluation would be a useful basis for designing an improved workspace.

• 정보처리학회논문지B
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• 제12B권5호
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• pp.535-542
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• 2005

증강 협업 환경은 지리적으로 떨어진 그룹과 그룹간의 사용자들이 함께 어려운 문제를 풀 수 있도록 도와주는 다수의 디스플레이를 활용하는 작업 환경이다. 본 논문은 실시간 협력 작업 환경의 특징적인 공유 작업 공간 모델을 살펴본다 그리고 과학적 가시화를 위한 증강 협업 환경의 공유 작업 공간 모델을 검증하는 반복적인 디자인 실험연구를 설명하고 있다 이 연구에서 원거리 사용자들의 협업을 향상시키기 위한 증강 협업 환경의 디스플레이 기술 설정을 바꿔가며 사용자 평가 실험이 진행되었다. 각 실험에서 두 개의 방에 두 명씩 분산된 그룹들에게 협업 가시화를 이용한 집중적인 분석 작업을 시켰다. 그 결과 다른 사람들의 작업 내용을 쉽게 볼 수 있는 고화질 작업환경의 항시 가시성이 분산된 구성원들 간의 상호 인지도와 협력에 도움이 되어 협업 능률을 향상시켰다.

• 제어로봇시스템학회논문지
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• 제5권3호
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• pp.288-296
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• 1999

A force-reflecting hand controller can provide the kinesthetic information obtained from a slave manipulator to the operator of a teleoperation system. The goal is to construct a compact hand controller that can provide large workspace and good force-reflecting capability. This paper presents the design and the analysis of a 6-degree-of-freedom force-reflecting hand controller using fivebar parallel mechanism. The forward kinematics of the fivebar parallel mechanism has been calculated in real-time using three pin-joint sensors in addition to six actuator position sensors. A force decomposition approach is used to compute the Jacobian. To evaluate the characteristics of the fivebar parallel mechanism, it has been compared with the other three parallel mechanisms in terms with workspace and manipulability measure. The hand controller using the fivebar parallel mechanism has been constructed and tested to verify the feasibility of the design concept.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.207-210
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• 2000

Singular points are those at which the determinant of a Jacobian matrix is zero. A parallel manipulator gains mostly an extra DOF at the singular points, where it can not be properly controlled. In this study, singular points of a cubic parallel manipulator are illustrated by obtaining the determinant of a Jacobian matrix mathematically, and the singular points of the manipulator are found to be three separate planes in a 3D space. The dependency among links for each singular point is determined by applying linear algebra. Also, the singular points and workspace of the cubic parallel manipulator are plotted to check if the workspace contain singular points.