• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2087-2093
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• 2006

In this paper, auto focus actuator, which is used to move a lens module in the mobile phone having a camera module, is developed. Camera module containing auto focus actuator requires to minimize total size because of characteristics of the application area such as mobile phone, digital camera, and personal digital assistant. There are stepping motor, voice coil motor, and piezoelectric motor as auto focus actuator. In this paper, voice coil motor having new electromagnetic configuration is proposed. And actuator using proposed voice coil motor is developed by optimal design method using magnetic circuit analysis. The sectional area of the developed actuator is reduced to 32.4% compared with actuator using general electromagnetic configuration. From the performance test, the developed actuator has moving stroke of 0.64 mm for 2.1 volt, hysteresis of 40 $\mu$m, full stroke current of 54 mA, and unit step motion of 3 $\mu$m.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.129-135
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• 2010

The state feedback-based position controller for the voice coil motor(VCM) used in precise automated manufacturing processes is proposed and analyzed in this paper. The proposed controller has advantage over the conventional cascade-type P-PI controller in terms of the gain selection and the controller interference. The feasibility of the presented idea is verified by experimental results on a designed VCM.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.331-335
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• 2012

Many researches have been performed the analysis and experiments on auto-focus lens due to the development of camera module which is used in mobile-phone recently. Various types of voice coil motor are used mostly in the view point of actuators. Various type of magnetic flux flow is made by the combination of magnet, coil and yoke, etc. And the function of auto-focus is made by the proper combination of the lens components. In this research, some of the simple and economic structure is chosen to investigate the characteristics analytically among various types of lens which are used in industries. Desired level of lens module design was achieved by electromagnetic analysis using ANSYS$^{TM}$ finite element analysis program.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.577-579
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• 2002

Propose of this paper is VCM (voice coil motor) design for application of Nanoindenter, which enable control of extremely small force and displacement. This paper present the VCM shape to produce a very small force by the difference of flux density of lower part from higher one. In wide range of current. VCM produces linear driving force and operate on regular thrust having maximum displacement(100um) was practiced.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.299-300
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• 2006

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.43-45
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• 2005

A High precision position control technique is used in many kind of industry areas. Especially this is to be one of the important parts in the development of precision machines. To get high precision and long range, dual servo voice coil motor(VCM) has been designed and implemented. In this paper, as a simulation and experimental result, the developed dual servo VCM shows the applicable possibility for precision machine system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.17-22
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• 2016

A voice coil actuator with moving coil type for scanning mirror system of barcode reader has been developed. The actuator has a simple structure including a magnet, a coil and a pin. The performance of the actuator is analyzed by a linearized theoretical model. And the dynamic performance of the proposed actuator is predicted through motor constant and restoring constant obtained by finite element simulations. The theoretical model was verified by the prototype which has 64 Hz resonance frequency and 60 deg reflecting angle. We also discovered that that 3 V input can make the actuator rotate over 61.8 deg reflecting angle at 50 Hz resonance frequency. The proposed actuator can simplify its driving configuration because of its implementation of open-loop control.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.152-158
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• 2001

In this paper, we have developed an electro discharge machine for micro drilling driven by a voice coil actuator. Because the voltage signal of the electro-discharging circuit shows a lot of peaks and valleys, the active type low-pass filtering technique is adopted to get the average of the signal. Since the motion of the voice coil is precisely controlled by the error value between the object voltage value and the measured one, it is possible to prevent the mechanical contact between the rotating electrode and the workpiece and to maintain the appropriate machining conditions during the process. The electro-chemical machining technology was also adopted to make small diameter electrodes. Pure water is used as a dielectric. The machining procedure is performed to verify the feasibility of the developed system. It takes about 10 seconds to drill the ${\phi}m$100${\mu}m$ hole to the 100${\mu}m$ thickness stainless steel plate. The machining time depends on the values of the resister and the capacitor. There may exist the optimal values of time constant and the tendency is displayed In the appendix.

• Journal of Aerospace System Engineering
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• v.18 no.4
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• pp.1-9
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• 2024

In this study, we researched control compensation techniques to enhance control robustness against external forces and responsiveness to output dead zones in direct-actuated voice coil actuators for small guided missiles. An aircraft's wings must optimally control the command angle while managing various nonlinear external forces such as drag, lift, and thrust during flight. The small direct -drive voice coil actuator, when applied, benefits from small current requirements in no-load situations but suffers from diminished control robustness due to rapid increases in control current during external force applications. To address this issue, we designed and implemented a system that compensates for errors by accumulating additional output, thus improving the actuator's responsiveness in control scenarios with external forces. This was verified through experimental results.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1439-1443
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• 2007

In this paper, vibration reduction techniques of a voice coil motor (VCM) actuator are presented for AFM imaging system. The damping coefficient of the actuator driven by VCM with a flexure hinge is quite low and it cause the about 30dB peak amplitude response at the resonance frequency. To decrease this peak response, we design and apply elliptical band-stop filters to xy and z axis VCM actuator. Frequency response of each actuator with filter is measured to verify the effect of the filters. As a sensor, capacitive sensor is used. Vibration reduction rate of the xy actuator with the filter is also measured while real AFM scanning condition. As another method, closed loop control with the capacitive sensor is applied to the xy axis actuator to add an electrical damping effect and vibration reduction rate measured. These vibration reduction rates with each method are compared. In the case of z axis actuator, the frequency response of force (gap) control loop is measured. For comparison, the frequency response using a conventional PID controller is also obtained. Finally, the AFM image of a standard grid sample is measured with the designed controller to analyze the effect in the AFM imaging.