• 제어로봇시스템학회논문지
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• 제3권4호
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• pp.422-434
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• 1997

In this paper, a two-stage kinematic optimal design for a 3 degree of-freedom (DOF) excavator subsystem, which consists of boom, arm and bucket, is performed. The objective of the first stage is to find the optimal parameters of the joint-actuating mechanisms which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the second stage is to find the optimal link parameters which maximize the isotropic characteristic of the excavator subsystem throughout the workspace. It is illustrated that kinematic/dynamic performances of the kinematically optimized excavator subsystem have improved compared to those of original HE280 excavator, with respect to three performance indices such as maximum load handling capacity, maximum velocity capability, and acceleration capability.

• 제어로봇시스템학회논문지
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• 제12권10호
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• pp.962-967
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• 2006

Indoor positioning is highlighted recently, and various kinds of indoor positioning systems are under developments. Since positioning systems have their own characteristics, proper positioning scheme should be chosen according to the required specifications. Positioning methods are classified into time-based and angle-based one. This paper presents the error analysis of time-based and angle-based location methods. Because measurements of these methods are nonlinear, linearizations are needed in both cases to estimate the user position. In the linearization, Gauss-Newton method is used in both cases. To analyze the position error, we investigate the error ellipse parameters that include eccentricity, rotation angle, and the size of ellipse. Simulation results show that the major axes of TOA and AOA method lie in different quadrants at most region of workspace, especially where the geometry is poor. When the TOA/AOA hybrid is employed, it is found that the error ellipse is reduced to the intersection of ellipses of TOA and AOA.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.617-622
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• 1994

In this paper, we perform a two-stage, kinematic optimal design for 3 degree-of-freedom excavator system which consists of boom, arm, and bucket. The objective of the first stage is to find the optimal joint parameters which maximize the force-torque transmission ratio between the hydraulic actuator and the rotating joint. The objective of the first stage is to find the optimal link parameters which maximize the isotropic characteristic throughout the workspace. It is illustrated that performances of the optimized excavator are improved compared to those of HE280 excavator, with respect to the described performace index and maximum load handling capacity.

• 대한기계학회논문집A
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• 제29권11호
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• pp.1509-1517
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• 2005

This paper presents the two degree-of-freedom(DOF) planar parallel mechanism called 2R$\underline{P}$R-RP manipulator, whose degree-of freedom is dependent on a passive constraining leg connecting the base and the platform. First, the kinematic analysis of the mechanism is performed analytically: the inverse and forward kinematic problems are solved in the closed font the practical workspace is systematically derived, and all of the singular configurations are examined. Then, in order to determine the geometric parameters and the operating limits of the actuators, the optimization of the mechanism is performed considering its dexterity and stiffness. Finally, the kinematic performances of the optimized mechanism are evaluated through comparing to the 5-bar parallel manipulator.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.313-318
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• 2001

A haptic hand controller operated by the user's hand can receive information on position and orientation of the hand and display force and moment generated in the virtual environment to the hand. This paper presents a design method for KU-HHC, 6 DOF Korea University-haptic hand controller, which allows separation of workspace from linkage mechanism in consideration of the efficient user operation. First, the 3 DOF mechanism in which all the actuators are mounted on the fixed base is developed by combining a 5-bar linkage and gimbal mechanism. Then, the 6 DOF HHC is designed by connecting the two 3 DOF devices through a handle. This paper presents the forward and inverse kinematics for this device and Jacobian analysis. Improvement of the kinematic characteristics using performance index is also discussed. The hand controller KU-HHC based on this design concept and kinematic analysis was manufactured and shows excellent performance.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.286-291
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• 2002

We present the analysis and design of a new six degree-of-freedom parallel mechanism, Eclipse-II, which can be used as a basis for general motion simulators. This mechanism allows x, y and z-axis translations and a, b and c-axis rotations. Most significantly, it presents the advantage of enabling continuous 360 degrees spinning of the platform. We first describe the computational procedures for the forward and in inverse kinematics of the Eclipse-II. Next, the complete singularity analysis is presented for the two cases of end-effector and actuator singularities. Two additional actuators are added to the original mechanism to eliminate both types of singularities with in the workspace. Some practical aspects of the prototype development are introduced.

• 대한기계학회논문집A
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• 제31권4호
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• pp.441-450
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• 2007

In this study, a 3-DOF XYZ micro parallel manipulator utilizing compliance mechanism is developed and analyzed. In so doing, a matrix method is used to rapidly solve displacements of the designed kinematic structure, and then kinematic characteristics of the developed manipulator are analyzed. Finally, the design analysis of the kinematic characteristics by changing hinge thickness and structure to improve workspace and translation motion is performed to show that the performance of the developed manipulator is relatively superior to the other similar kind of manipulators.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.187-192
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• 2007

In this paper we present a 3-DOF manipulator of which task is to unload the product from a micro factory. The micro factory developed by KITECH presses sheet metal to produce a micro valve that is used for micro pump. Our research is focused on the development of a small-sized unloading manipulator which works in the narrow workspace between the dies. We have implemented pick-and-place task with vacuum pressure and 3-DOF motion with stepping motors. We present the design procedures and analysis required in each module.

• 산업공학
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• 제24권4호
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• pp.387-395
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• 2011

This study was aiming to examine work time, frequency, work environment, and postures of retail grocery store workers to evaluate the risk of musculoskeletal disorders. An ergonomic evaluation was conducted using job analysis and posture analysis. The four most time-consuming tasks were inspecting (27.4%), arranging (21.4%), cutting (17.6%), and displaying (15.6%). The height and length of the shelves evaluated in the field was inappropriate for workers. The most common posture was a standing posture with neutral back, and bent head, right upper arm, lower arms, and hands. Finally, this paper concluded that 'arranging,' 'cutting,' and 'displaying' seemed more stressful than other operations. The result of the ergonomic evaluation would contribute to design a better workspace in ergonomics.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.1129-1135
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• 1993

For successful implementation of robotic painting system, a structured design and analysis procedure is necessary. In designing robotic system, both functional and economical feasibility should be investigated. As the robotization is complicated task involving implementation details(such as robot selection, accessory design, and spatial layout) together with operation details, a computerized method should be sought. However, any conventional robotic design system and off-line programming system cannot accomodate such a need. In this research, we develop an interactive design support system for robotization of a cycle painting line. With the developed system called SPRPL(Simulation Package for Robotic Painting Line) users can design the painting objects(via FRAME module), select robot model (ROBOT), design the part hanger (FEEDER), and arrange the workcell. After motion programming (MOTION), the design is evaluated in terms of: a) workspace analysis, b) coating thickness analysis, and c) cycle time (ANALYSIS). By iterative design and evaluation procedure, a feasible and efficient robotic design can be attained. As the developed system has motion planning and analysis features, it can be also used as an off-line robot programming system in operation stage. Including the details of each module, this paper also presents a case study made for an actual painting line.