• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.182-184
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• 2001

Linear pulse Motor(LPM) are used a field where smooth linear motion is required, and it's position accuracy higher than that of a lead. According to the advantage such as simplicity of mechanical frame, high reliability, precise open_loop operation, low inertia etc LPM is applied largely where it have made motor of this kind more and more attractive in many application areas such as factory automation and high speed positioning. This paper is researched to analyze for thrust force characteristic of hybrid LPM. Both the thrust and normal force are very sensitive to the airgap and tooth pitches of the force and platen. To find the optimal design parameter on the hybrid LPM for the embroidery machine. For the field analysis, the finite element method(FEM) is employed for calculating the force. The reluctance models will be used the magnetic permeance of airgap under static-conditions. The forces between forcer and platen have been calculated using the virtual work mathod.

• Structural Engineering and Mechanics
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• v.22 no.4
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• pp.433-447
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• 2006

The problem of very large deflection of a circular cantilever arc device subjected to inward or outward polar force is studied. An exact elliptic integral solution is derived for the two cases and the results are checked using large displacement finite element analysis via the ANSYS package by performing a new novel modeling simulation technique for this problem. Excellent agreements have been obtained between the exact analytical solution and the numerical approach. From this study, a design chart for engineers is developed to predict the required value for the inward polar force for the device to switch on for a given angle forming the circular arc (${\theta}_o$). This study has several interesting applications in mechanical engineering, integrated circuit technology, nanotechnology and especially in microelectromechanical systems (MEMs) such as a MEM circular device switch subjected to attractive or repulsive magnetic forces due to the attachments of two magnetic poles at the fixed and at the free end of the circular cantilever arc switch device.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.85-89
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• 2007

Linear ball guideways have been used recently in precision or ultra-precision positioning devices. However, when the inner balls begin to roll or the moving direction reverses, these guideways are subject to rolling friction or nonlinear spring behavior. An ultra-precision device with a linear motor, referred to as a 'tunnel actuator' (TA), has been constructed to measure these phenomena. The application of a TA is beneficial for two reasons: it mostly cancels the attractive magnetic force between the stator and mover (armature), and its magnetic flux leakage is very low. The influence of the nonlinear spring behavior in ball guideways was investigated in this study using the pure driving force from a TA. The equilibrium between the driving force from the TA and the nonlinear spring force provided great accuracy for a positioning stage using a linear ball guideway.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1428-1433
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• 2014

In this paper, we propose the formation control algorithm using the leader-following robots in given space. The proposed method is as follows: First, we plan a path of the leader robot for the obstacle avoidance. After that, we propose the formation control algorithm of the following robots using the position and the orientation angle of the leader robot. Also, we propose method for adjusting the formation of the swarm robots when the following robots detect an obstacles. Finally, we show the effectiveness and feasibility of the proposed method though some simulations.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.11
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• pp.581-588
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• 2001

This paper presents theoretical and experimental study on the quality-factor of the laterally oscillated electrostatic microactuator, driven by a lateral repulsive-force generated by the asymmetry of planar electric field. The quality-factor of the repulsive-force microactuator using a creeping flow model of the ambient air is evaluated. By filling the simulation results of damping force, we evaluate the dimensionless damping force, $\alpha$, thereby obtaining an analytical damping force, F, in the form of $F=\mu\; \alphaUL,\; where\; \mu,$ U and L denote the air viscosity, the velocity and the characteristic length of the movable electrodes. The measured quality-factor increases from 12 to 13 for the DC bias voltage increased from 60V to 140v. The theoretical quality-factor estimated from the creeping flow model increases from 14.9 to 18.7. Characteristics of quality-factor of the repulsive-force microactuator have been discussed and compared with those of the conventional attractive-force microactuator.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.527-533
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• 2005

The linear hybrid stepping motors (LHSM) has been widely used due to its simple structure and low cost control. Despite of its attractive features, the conventional LHSM has the multiples of 4th times harmonic reluctance force from excitation current and cogging force from space harmonic of permeance. This paper propose a new LHSM, which the mechanical and electrical phase difference are $45^{\circ}$. The proposed motor shows a unique ability to deliver low detent force and we propose a closed-loop control scheme to attack the ripple force for high performance applications. An analytical and experimental comparison between conventional and proposed LHSM is evaluated to confirm the effectiveness of the proposed modeling and control scheme.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.781-784
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• 2002

Adhesion phenomenon is more significant for smaller objects, because adhesional force is proportional to size of the objects while gravitational force is proportional to the third power of it. For the purpose of microassembly, theoretical understanding is required for the Adhesion phenomenon. Authors have developed a force measurement system in an ultra-high vacuum chamber of Auger electron spectroscopy. The force between arbitrary combination of materials can be measured at a pressure less than 100 nPa after and before Ar ion sputtering and chemical analysis for several atomic layers of the surface. The results are successfully interpreted with a theory of contact mechanics. Since surface energy is quite important in the interpretation, electronic theory is used to evaluate the surface energy. In the manipulation of small objects, the adhesional force is always attractive. Repulsive force is essential for the manipulation. It can be generated by Coulomb interaction. The voltage required for detachment is theoretically analyzed and the effect of boundary conditions on the detachment is obtained. The possibility and limitations of micro-manipulation using both the adhesion phenomenon and Coulomb interaction are theoretically clarified. Its applicability to nano-technology is found to be expected.

• 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.

• Transactions of The Korea Fluid Power Systems Society
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• v.2 no.3
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• pp.1-5
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• 2005

There are two types of solenoid actuator for force and position control of the fluid power system. One is an on-off solenoid actuator and the other is an electro-magnetic proportional actuator. They have some different characteristics for attraction force according to solenoid shape. Attraction force of the on-off solenoid actuator only depends on flux density. And the stroke-force characteristics of the proportional solenoid actuator are determined by the shape of the control cone. In this paper, steady state characteristics of the solenoid actuator for electro-hydraulic proportional valve determined by the shape of control cone are analyzed using finite element method and it is confirmed that the proportional solenoid actuator has a constant attractive force in the control region independently on the stroke position. And the shape of control cone is optimized using 1+1 evolution strategy to get a constant force. In the optimization algorithm, control cone length, thickness and taper length are used as a design parameter.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.59-63
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• 2011

Friction damping is one of the attractive vibration control technique for space structures due to its simplicity and large damping capacity. However, passive approaches for friction damping have a limitation because energy is no longer dissipated at sticking. In order to overcome this problem, semi-active control methods to adjust normal force at frictional interface have been studied in previous researches. In this paper, two semi-active friction control method is compared by simulating SDOF model of truss structure. The first approach is on-off control to maximize rate of energy dissipation, whereas the second concept is variable friction force control to minimize amplitude ratio for each half period. The maximum friction force, control variable in on-off control method, is obtained to minimize 1% settling time, and is different from optimal friction force in passive control. Simulation results show that performance of on-off control is better than that of variable friction force control in terms of settling time and controlled friction force.