• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.879-882
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• 2005

This paper shows a method for design of the nano-positioning planar scanner used in the scanning probe microscope. The planar scanner is composed of flexure guides, piezoelectric actuators and feedback sensors. In the design of flexure guides, the Castigliano's theorem was used to find the stiffness of the guide. The motion amplifying mechanism was used in the piezoelectric actuator to achieve a large travel range. We found theoretically the travel range of the total system and verified using the commercial FEM(Finite element method) program. The maximum travel range of the planar scanner is above than 140 $\mu$m. The 3 axis positioning capability was verified by the mode analysis using the FEM program. Moreover, we presented the actual AFM(Atomic Force Microscope) imaging results with up to 2Hz imaging scan rate. Experimental results show that the properties of the proposed planar scanner is well enough to be used in SPM applications like AFM.

• Design & Manufacturing
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• v.16 no.3
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• pp.22-27
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• 2022

The demand for new processing technology that can improve productivity is increasing in industries that require large-scale and various products. In response to this demand, a robot machining system with flexibility is required. Because of the low rigidity of the robot, the robot machining system has a large error during machining and is vulnerable to vibration generated during machining. Vibration generated during machining deteriorates machining quality and reduces the durability of the machine. To solve this problem, a stage for fixing the spindle during machining is required. In order to compensate for the robot's low rigidity, a system combining a piezoelectric actuator for generating a large force and a guide mechanism to actuate with a desired direction is required. Since the rigidity of flexible hinges varies depending on the structure, it is important to optimal design the flexible hinge and high-rigidity system. The purpose of this research is to make analytic model and optimize a flexible hinge and to design a high rigidity stage. In this research, to design a flexible hinge stage, a concept design of system for high rigidity and flexure hinge modeling is carried out. Based on analytic modeling, the optimal design for the purpose of high rigidity is finished and the optimal design results is used to check the error between the modeling and actual simulation results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.653-656
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• 2005

This paper introduces design, fabrication and experiment process of a novel scanner for the high speed AFM(Atomic Force Microscope). A proper design modification is proposed through analyses on the dynamic characteristics of the existing linear motion stages using a dynamic analysis program, Recurdyn. Since the scanning speed of each direction is allowed to be different, the linear motion stage for the high-speed scanner of AFM can be so designed to have different resonance frequencies for the modes with one dominant displacement in the desired directions. One way to achieve this objective is to use one-direction flexure mechanism for each direction and to mount one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separates the frequencies of the two vibration modes with one dominant displacement in each desired direction, hence, the coupling between the motions in the two directions. In addition, a pair of actuators is used for each axis to decrease the cross talks in the two motions and gives a force large enough to actuate the slow motion stage, which carries the fast motion stage. After these design modifications, a novel scanner with scanning speed higher than 10 Hz can be achieved to realize undistorted images in the high speed AFM.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1344-1348
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• 2003

A precision micro-positioning system with a high displacement resolution and wide motion range has been required for industrialized applications in variety fields. This paper discusses the design of a precision micro-rotation stage with flexure hinges. Proposed system is applied to grinding machine for micro parts. Rotational motion is generated with this system. For this systems having a full rotation motion with high precision, a dual servo system with a coarse stage and a fine stage is proposed.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.106-113
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• 2009

A 6-DOF precision stage was developed based on parallel kinematics structure with flexure hinges to eliminate backlash, stick-slip and friction and to minimize parasitic motion coupled with motions in the other-axis directions. For the stage, lever linkage mechanism was devised to reduce the height of system for the enhancement of horizontal stiffness. Frequency response comparison between experimental results and mathematical model extracted from dynamics of the stage was performed to identify the system parameters such as spring constants and damping coefficients of actuation modules, which cannot be calculated accurately by analytic methods owing to their complicated structures. This newly developed precision stage and its identified model will be very useful for precision positioning and control because of its high accuracy and non-coupled movement.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.3
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• pp.111-119
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• 2006

The ultra-precision stage is demanded for some industrial fields such as semiconductor lithography, ultra-precision machining, and fabrication of nano structure. A new stage was developed for those applications in order to obtain nano meter resolution. This stage consists of symmetric double parallelogram mechanism using flexure hinges. The mechanical properties such as strength of the flexures and deformations along the applied force were analyzed using FEM. The stage is actuated by a piezoelectric actuator and its movement was measured by a ultra-precision linear encoder. In order to improve positioning performance, a PID controller was designed based on the identified second order transfer function. Experimental results showed that this stage could be positioned within below 5 nm resolution irrespective of hysteresis and creep by the controller.

• Steel and Composite Structures
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• v.6 no.4
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• pp.335-351
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• 2006

The present paper hopes to elucidate the problem of determining if a given I-shaped cross-section is properly proportioned to accommodate sufficient plastic hinge rotation capacity to facilitate the redistribution of moments in a structural system as needed to accommodate the formation of a collapse mechanism. It might be tempting to believe that application of the limiting flange plate slenderness value for the case of major axis flexure are applicable in this case; since the pervasive belief is that this approach ought to be conservative. However, the present research study indicates that this is not the case and thus more sophisticated analysis techniques are required to better understand this case.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.3
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• pp.419-425
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• 2010

To machine the micro hole, laser machining system is widely used, however, the system cannot fabricate the micro hole with high aspect ratio and good surface finish. To break the obstacles, the high frequency vibration mechanism with PZT (Piezoelectric Transducers) is proposed in this paper. The mechanism will vibrate the laser beam in vertical direction so that the aspect ratio and surface finish may be higher than the conventional. The mechanism vibrates the eyepiece of laser optics. In addition to the benefits, the mechanism enables us to have high precision and flexibility. It decreases burr and debris during machining. And it is able to machine various materials of workpiece. This research include high frequency and large travel range of the proposed mechanism. The PZT motion of mechanism and analysis on the sensitivity of design parameters are extracted from a finite element method (FEM) simulation. In the analysis, the target vibration mode without parasitic motion is designated to have the target frequency and high amplitude.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.249-254
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• 1993

In order to respond to the increasing demands of ultraprecision positioning mechanism in the field of precision engineering, more accurate stages are needed whose positioning uncertainty should be in the unprecedented level of nanometers, while maintaining a long travek range. For this application, most conventional stage mechanisms are found not suitable, so the concept of dual servo, which uses two different servos, is one of the new design and control strategies being extensively investigated these days, This paper presents a fine motion mechanism as a part of research on the dual servo control. The stage is made of a single structure of elastic flexure, whose xy .theta. motions are induced in the form of elastic deformation activated by three piezoelectric actuators. Experimental results show that the translational and rotational motions of the stage can be controlled with resolutions of 5 nm and 0.1 arcsec, respectively.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1309-1314
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• 2003

The high precision positioning mechanism is used in various industrial fields. It is used in semiconductor manufacturing line, test instrument, Bioengineering, and MEMS and so on. This paper presents a positioning mechanism with dual servo system. Dual servo system consists of a coarse stage and a fine motion stage. The course stage is driven by VCM and the actuator of fine stage is the PZT. The purposes of dual servo system are stability, higher bandwidth, and robustness. Lead compensator is applied to this control system, and is designed by PQ method. Designed compensator can improve property of positioning mechanism.