• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1444-1446
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• 2005

Recently most machineries have been small size and mobile type. And human body insertion type endoscope and micro robot technology has been developed. Then the motors used in this field are developed in micro size such as about 2mm in diameter. The structure of this motor is similar to a general brushless DC(BLDC) motor but because of small size there is no position sensor such as hall sensor. In this paper, a design and fabrication result of an ultra-small brushless DC motor is presented. This motor is designed to 3-phase coreless winding and operated with sensor-less type driver. Test results confirmed the feasibility of the proposed motor drive system design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.2
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• pp.169-176
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• 2013

To generate the walking path of a humanoid robot in an unknown environment, the shapes of obstacles around the robot should be detected accurately. However, doing so incurs a very large computational cost. Therefore this study proposes a method to classify the obstacle shape into three types: a shape small enough for the robot to go over, a shape planar enough for the robot foot to make contact with, and an uncertain shape that must be avoided by the robot. To classify the obstacle shape, first, the range and the number of the obstacles is detected. If an obstacle can make contact with the robot foot, the shape of an obstacle is accurately derived. If an obstacle has uncertain shape or small size, the shape of an obstacle is not detected to minimize the computational load. Experimental results show that the proposed algorithm efficiently classifies the shapes of obstacles around the robot in real time with low computational load.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.476-479
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• 2003

Recently, Bluetooth has been regarded as a new technology for short-range wireless connection. Although initial application of Bluetooth technology has been focused mainly on replacing cables between hand-held devices due to a limited packet size and short-range, general wireless telecommunication such as PAN and Ad hoc networks via Bluetooth-equipped devices is expected to be one of the most popular applications. Wireless equipments have been used to exchange data between host and mobile unit. The exchanging data may be several bytes of control command and the value of sensors with ultra-sonic, vision sensor, and encoder from mobile robot. However, most wireless equipments have some drawbacks such as lack of authentication, large size and high price. On the other hand, the benefits of Bluetooth are small size, low power, low price except short-range. Especially, there are some difficulties when wireless modules are used in indoor environments. In this paper, a method of using wire network in Bluetooth network is investigated as a solution to overcome the short-range problem of Bluetooth and difficulty in indoor environment.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.164-173
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• 1999

Robot calibration needs accurate measurements of robot end-effector position at a number of different robot configurations. One of the efficient ways of the measurement is "Touching on Jig" method suggested in [7], which utilizes a touch sensor and a fixture consisting of various sizes of blocks. By moving the end-effector to touch the surface of a block whose position relative to the other is known, the end-effector position relative to the fixture coordinate system can be obtained at the instant of touching. However, the global size of fixture is too small to cover the various configurations of the robot. Because of the manufacturing difficulties, the fixture cannot be manufactured large enough for well distributed position measurement. It results in the improvement of robot accuracy only in the limited space near to the fixture rather than over the whole space of the robot working volume. The paper proposes a method to resolve the above problem by measuring the end-effector positions with respect to several different coordinate system using the same measurement devices. It is found that the proposed method leads the improvements of robot position accuracy over the large space of working volume. The experimental studies are performed to show the validity of the method and their results are discussed.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.10
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• pp.1181-1188
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• 2011

A control system for stabilizing a small robot or inverted pendulum using twisted gyro wheel is proposed. Conventional stabilizer using inertial wheel employs action-reaction force/torque to control a pendulum, which can generate relatively small torque and short period of output. In this paper, a novel actuation method using twisted gyro torque in 3-dimentional space was proposed to stabilizing a pendulum by twisting the assembly including a rotating gyro wheel. In addition, two special control functions for this type of twisted gyro wheel were designed. One is the function of self-adjusting the mass center of the robot and the other is the torque reloading configuration for continuous torque generation. The proposed system was verified by experimental result and simulation. The designed twisted gyro wheel control system can be easily packed in a small size module and installed in a humanoid robot or inverted pendulum type mechanism.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.603-608
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• 2007

In the conventional AOA(angle-of-arrival) positioning utilizing reverse-link wireless channel, each sensor should be equipped with an array antenna to measure the incident angle of signal transmitting from a tag. To perform the complicated signal processing for angle measurements, sensor size and its power consumption will be large. In some applications like mobile robot location, there exists no strict restriction in tag size or in power consumption. Rather, it is desirable that the sensor would be as small as possible. This paper presents a new AOA positioning method utilizing forward-link channel. Under the assumption that the mobile robot is operating on the flat surface, the measurement model for FLAOA(tiJrward-link AOA) is derived first. Two kinds of position estimation algorithms using FLAOA measurements are proposed; Gauss-Newton method and closed-fonn solution method. With the proposed methods, we can ohtain the attitude of robot as well as its position. Positioning performance of proposed methods is compared by computer simulation. Simulation results show that the closed-form solution method using FLAOA measurements is suitable for indoor robot positioning.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.908-911
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• 2004

There are various researches on mobile robot systems. Connection method between server and client of mobile robot system is one of them. In the case of mobile robot system, when connection method between server and client is wireless than wire, applications may be expanded. Also in remote monitoring environment using mobile robot system, we are interested in an effective transmission of the image information between server and client. In this paper, Bluetooth is used for connection method between server and client. One of the major applications of Bluetooth is the cable replacement for mobile and peripheral devices. Using Bluetooth, we propose the control method of mobile robot system. Bluetooth offers fast and reliable transmissions of both voice and data over the globally available 2.4GHz ISM (Industrial, Scientific and Medical) band. It has the advantage of small size, low power and low cost. It has the disadvantage of limited range and limited bandwidth. Also in order to transfer effectively image information between remote site(server) and mobile robot system(client) using Bluetooth, we applied to MPEG-2 and MPEG-4 image compression techniques and the results are compared with each other.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.4
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• pp.359-367
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• 2015

The forces and moments exerted on humanoid robot foot are important information for controlling or monitoring the robot. Multi-axis force/moment sensor can be installed under humanoid robot foot to measure forces and moments. The sensor should have large stiffness to support the robot weight and small size not to disturb the motion of the robot. In this paper, we designed a 6-aixs force/moment sensor which has good accuracy, large measuring range, and new compact structure. In addition, the proposed sensor is evaluated using analytical method and FEM(Finite Elements Method) method. Finally, it turned out that it has good performance.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.985-989
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• 1990

This paper presents a fundamental study of a millimeter-sized master-slave robot driven by conduit-guided wires, which is expected to be applied to the delicate surgical operations, the assembling precise and small parts and so on. This system consists of a millimeter-sized slave robot and a master manipulator of which the size is adapted to a human finger. Displacement and torque of the master side can be reduced and transferred to the slave robot by controlling the motor torque against the master torque by feeding back tension signals. The master can feel the tensions by the motor torque. In this paper, the design method and making process of the master-slave system and the dynamical characteristic of displacement and torque control are proposed.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.9
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• pp.923-930
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• 2013

These days, the interests on the high speed handling robots are increasing because it is important to get down the unit cost of production to get the price competitiveness. The parallel kinematic mechanism is more suitable to implement the high speed robot system as well known. The moving parts of the high speed parallel robot have to be designed for light weight. But the vibration motion is induced by the light weight links because they drive in high acceleration and deceleration. In this reason, the structural analysis of the high speed parallel kinematic robot is very important in the design process. In this paper, the study on the structural analysis of a high speed parallel robot has been done and the research results will be introduced.