• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.6
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• pp.954-959
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• 2003

Colonoscopy is an important medical procedure for the diagnosis of various diseases like cancers in the colon and rectum. But it requires a lot of time for a doctor to acquire dexterous skills necessary to perform successful colonoscopy. Moreover, to many patients, conventional colonoscopy simply takes too long time. Therefore, some studies on the development of autonomous and more convenient colonoscope are carried out. In this Paper, we Propose a functional colonoscope robot system that has a locomotive function with a hollow body, a steering system, and other basic functions of typical conventional colonoscope systems. The concept and each component of the functional colonoscope system are described in this paper. In order to evaluate the functional performance of the colonoscope robot, we carried out in -vitro and in-vivo tests.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.371-375
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• 2001

The concept of a new linear motor that uses piezo-stack actuator is demonstrated. The working principle is far different from the conventional inchworm motor. This motor is based on the self-moving cell concept. The linear motor has three cells and each cell is constructed with one piezo-stack actuator and a shell structure. A cell train is constructed by connecting these cells and the cell train is fitted into a guide way with a proper interference. The cell train moves along the guide way, by activating each cell in succession. The moving motion of the motor is tested. Since this linear motor uses piezo-stack actuator with unified clamping cell, it can produce fast speed, high resolution and large push force.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.11 s.176
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• pp.151-158
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• 2005

Micro-machine tool is essential in the micro/meso cutting for the sake of saving of space, resources, and energy. In this research, a micro-turning lathe was fabricated with piezoelectric feed drive mechanism, and motion of each axis was generated by stepwise mechanism with two piezo actuators. The resolution to drive the axis was $0.05{\mu}m$ and position accuracy less than $2{\mu}m$ was assured. From the positioning experiment, piezo feed mechanism is good enough for the micro machine tools. Many fuming experiments were carried out with diamond-cutting tools to evaluate cutting capability of a machine tool. Continuous flow type chip could be obtained even if the cutting speed was very low due to small diameter of workpiece. However, thorough investigation about machineability in micro/meso cutting is inevitable to assure high quality surface roughness in micro machine tool.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.220-225
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• 2002

In this paper, we suggest a new locomotive mechanism fur self-propelling robotic endoscope which could substitute conventional endoscope. Many researchers proposed inchworm-like mechanism for self-propelling robotic endoscope. But it could not be commercialized because they did not solve the limitation caused by clamping. Therefore, we suggest a new radial-type locomotive mechanism with worm. It can propel itself in any situation and take passive-steering because of radial type. In addition, it can be miniaturized with worm. In this paper, we evaluate the mechanism in the dead pig colon as well as under various environments, and verify the performance fur robotic endoscope.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1793-1797
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• 2003

After the micro turning lathe was developed in the last year by AMR Laboratory in Yeungnam university, a micromilling machine is developed for micro/meso machining. This machine is integrated with PZT-driven micro-sliders, micro-linear encoders, aerostatic spindle which has maximum 150,000 rpm. It is applicable to milling and drilling of micro scale. This paper presents the possibility of micro/meso machining and characteristics of micro end milling process by using micro machine. A machining of micro parts using 0.2 mm flat end mill was achieved by micro-milling machine. Experimental results show the machining capability and positional accuracy of this machine is good enough for machining micro parts.

• The KIPS Transactions:PartA
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• v.8A no.2
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• pp.167-178
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• 2001

This paper presents a new methodology for specification and control of the motion of an articulated rigid body for the purposes of animation by coordinate transformations. The approach is to formulate the problem as a coordinate transformation from the joint space of the body to a user-defined animation space which is chosen for convenience in constraining the motion. Constraints are applied to the resulting coordinate transformation equations. It is sufficiently general so that it can be applied to all common types of control problems, including closed loop as well as open loop mechanisms. We also provided a new approach to simulate a closed loop mechanism, which is using animation space transformation technique. The method is formulated in detail and is demonstrated by animating the motion of an inchworm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.40-44
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• 2005

Recently PZT is used in ultra precision mechanism field. PZT itself has a small driving range although it has a high resolution. Many methods, such as inchworm, impact driving, inertial sliding method, etc., have been applied for moving range expansion. In this study, a new actuating mechanism for rotational motion with two driving PZT is proposed. The Fixed-Fixed beam support is applied for compensation of the difference in driving force between expansion and contraction of PZT. The behavior and design parameters of the proposed mechanism are analyzed for improving performance.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.446-452
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• 2005

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step by step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes a voltage control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.543-550
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• 2005

Recently, there are many studies for the micro-machining using Piezo actuator. However, because of its step by step motion, it is nearly impossible to increase the machining accuracy for a circular path. To increase the accuracy, it is well known that it is necessary the finer and synchronous movement for x-y axes. Therefore, this paper proposes an adaptive control for finer movement of the actuator, and realizes a synchronous control for the x-y axes. The experimental results show that the machining accuracy is remarkably improved.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1438-1445
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• 2002

For robotic endoscope, some researchers suggest pneumatic actuators based on inchworm motion. But, the existing endoscopes have not been replaced completely because human intestine is very sensitive and susceptible to damage. We design and test a new locomotion of robotic endoscope that allows safe maneuverability in the human intestine. The actuating mechanism is composed of two solenoids at each side and a single permanent magnet. When the current direction is reversed, repulsive force and attractive at the opposition side propels permanent magnet. Impact force against robotic endoscope transfers momentum from moving magnet to endoscope capsule. The direction and moving speed of the actuator can be controlled by adjustment of impact force. Modeling and simulation experiments are carried out to predict the performance of the actuator. Simulations show that force profile of permanent magnet is the dominant factor for the characteristic of the actuator. The results of simulations are verified by comparing with the experimental results.