Papers by Author: Dae Gab Gweon

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Authors: Ki Hyun Kim, Dae Gab Gweon, Hyun Soo Jung, Soo Hun Lee, Min Sung Hong, Moon G. Lee
Abstract: Design of design of X-Y-Theta fine stage using VCM (voice coil motor) is presented in this paper. This fine stage is combined with linear DC motor. Long range, high speed and high precision of the stage is obtained by using dual servo control for laser micro/nano machining. A novel structure of VCM for the fine stage is proposed. The fine stage can have 3 DOF(X-Y-Theta) motion by four VCM actuators which are located on the same plane. The X-Y-Theta fine stage is designed to have high acceleration for high throughput. Based on the design, the stage is fabricated. The designed stage has the acceleration of 5m/s2 with 45kg total mass. In addition, this actuator is feedback controlled using HP laser interferometer. The reaction force between the coarse and fine stage of the dual servo is compensated by force compensator.
Authors: Hyo Young Kim, Jung Jae Kim, Da Hoon Ahn, Dae Gab Gweon, Chan Gon Park, Dong Pyo Hong
Abstract: Flexure hinges have been widely used as mechanisms for high precision positioning stages that have a micrometer or nanometer resolution. This paper describes the analysis of a 3-DOF rotationally symmetric hinge for the vertical mask aligner stage. The vertical mask aligner stage was designed to overcome the bending of masks by gravity. In order to align the mask and the wafer, the vertical mask aligner stage has one linear motion and yaw rotating motions (Z, Θx, Θy). The new vertical mask aligner stage will try to use rotationally symmetric hinges. These rotationally symmetric hinges would act as guide mechanisms. However, the exact 6-DOF stiffness analysis of the rotationally symmetric hinge did not use these hinges as guide mechanisms. Therefore, this paper focuses on the stiffness analysis of the rotationally symmetric hinges.
Authors: Dong Yeon Lee, Dae Gab Gweon
Abstract: This paper shows a method of designing a nano-positioning planar scanner that can be used in a scanning probe microscope. The planar scanner is composed of flexure guides, piezoelectric actuators and feedback sensors. Furthermore, we used a motion amplifying mechanism in the piezoelectric actuator to achieve a large travel range. We theoretically determined the travel range of the total system and verified the range by using a program based on a finite element analysis. The maximum travel range of the planar scanner was greater than 120 μm. A planar scanner of an atomic force microscope can move samples with a few nm resolutions. To get stable AFM images of small feature samples, a closed loop control could not be used due to large random errors of the sensor. The orthogonality of a new planar scanner having a motion guide is measured and corrected by using a simple electronic circuit in the open loop scanning to reduce the scanner artifact.
Authors: Da Hoon Ahn, Dong Pyo Hong, Dae Gab Gweon
Abstract: Voice coil motor is an electromagnetic actuator widely used for motion generation. The main weakness of a voice coil motor is small force. In this paper a voice coil motor is mathematically modeled, analyzed and optimized to obtain high force. According to the optimized final designs, the performance of the voice coil motor is evaluated.
Authors: Myeong Hyeon Kim, Hyun Chang Kim, Dong Pyo Hong, Dae Gab Gweon
Abstract: This paper proposes the concept development and design of a VCM actuator for Active Vibration Isolation System (AVIS). Active vibration isolating method was constructed passive isolator and active isolator. Spring was used for isolating passively and actuator like voice coil motor was used for active isolating. The proposed active vibration isolating system could isolate a six degree-of-freedom disturbance effectively. In case of AVIS, payload is variable according to the type of instruments. Therefore, actuator should maintain uniform performance with payload change. The proposed VCM actuator satisfied this performance through relative relation between magnet array and coils. In addition, for maximizing actuator performance, actuator should generate large force density. Therefore, we apply the Halbach magnet array to proposed actuator. The Halbach magnet array helps with reinforcing magnetic flux field. The reinforced magnetic field takes a role to generate more powerful Lorentz force to isolate disturbance. Finally, in this paper, we propose the actuator that novel type using voice coil motor with the Halbach magnet array and optimize each design variables to generate maximum output. These AVIS can use to eliminate disturbance in Maglev stage. Maglev stage need AVIS to increase its performance is necessary. In the future, AVIS and Maglev system will be integrated.
Authors: Kyoungchon Kim, Dae Gab Gweon, Dong Pyo Hong, Byoungkuk Lee
Abstract: Dynamic performance in the H-type stage as precision positioning system is important specification to guarantee precise accuracy. As the range of the H-type stage has increased, the dynamic performance affects the settling time of the H-type stage. This article concentrates analysis of the dynamic modeling of the H-type stage with rotational flexure joint. The dynamic modeling of the H-type stage was analyzed using Lagrange method assumed as lumped mass-spring system. The dynamic modeling of the H-type stage was verified by the experiment.
Authors: Da Hoon Ahn, Dae Gab Gweon, Dong Pyo Hong
Abstract: This letter suggests a method to improve tracking performance of an H-type XY stage with air bearings and flexure hinge mechanisms. The flexure hinge mechanisms are employed to prevent failure of the air bearings when the yaw motion error of the H-type stage is controlled using a control algorithm called gantry control. Adoption of the flexure hinge mechanism combined with the gantry control leads to occurrence of mutual ripple. Ripple should be handled to obtain good tracking performance. Modeling of the mutual ripple and simulation of two compensation algorithms are presented.
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