• 로봇학회논문지
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• 제2권2호
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• pp.178-182
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• 2007

Precision stages are essential device for micro machines, fiber optic assembly systems, and biology instruments. In this paper, a precision inchworm type actuator for a linear stage is proposed and evaluated. An analytic method to design an inchworm type motor is proposed. Developed actuator provides fast motion compared with a commercial inchworm actuator, and can be used as an actuator for a stage in substitution for a conventional rotary actuator.

• 한국정밀공학회지
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• 제22권10호
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• pp.174-185
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• 2005

This paper presents the design, fabrication, and testing results of a dual stage actuator system for a fine positioning of magnetic heads in magnetic disk drives. A novel rotary microactuator which is electrostatically driven and utilized as a secondary actuator was designed. The stator and rotor electrodes in the microactuator was revised to have the optimal shapes and hence produces much higher rotational torque compared with the conventional comb-shape electrodes. The microactuators were successfully fabricated using SoG(silicon on glass) processing technology, which is known as being cost-effective. The fabricated microactuator has the structural thickness of $45{\mu}m$ with the gap width of approximately $3{\mu}m$. The dynamic characteristic of microactuator/slider assembly was investigated, and its natural frequency and DC gain were measured to be 3.4kHz and 32nm/V, respectively. The microactuator/slider assembly was integrated into a HDD model V10 of Samsung Electronics Co. and a dual servo algorithm was tested to explore the tracking performance of dual stage actuator system where the LDV signals instead of magnetic head signals were used. Experimental results indicate that this system achieves the tracking accuracy of 30nm. This value corresponds to a track density of 85,000 track per inch(TPI), which is about 3 times greater than that of current hard disk drives.

• 한국기계가공학회지
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• 제15권6호
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• pp.115-121
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• 2016

The aircraft flight control system controls an aircraft's direction and flying attitude, and actuators are key components of control systems. Actuators can be classified as Geared Rotary Actuator (GRA) and Ball Screw Actuator (BSA). GRA is used in mid-sized aircraft, and BSA is used in larger aircraft. A two-stage differential GRA model was suggested in this paper, and structural analysis and performance tests were performed. According to the analysis and experiment, the stiffness of the two-stage differential GRA was 17.57% higher than that of the conventional GRA, and the structural safety was improved.

• 연구논문집
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• 통권28호
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• pp.101-110
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• 1998

This study discusses the developement of hydraulic rotary actuator design technology for industrial machinery and earthmoving equipment. The lubrication and wear analysis of sliding components of the machinery are very important parameters to strength the design technique. The analysis and wear test are performed for the selected materials of the above mentioned coupled sliding members. The can be used to select the better combinations of sliding components.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1441-1442
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.346-350
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• 1996

In optical disk drives, one of commonly used pickup actuator is a Sliding and rotary type of pickup actuator which is cheaper than other pickup actuators and has simple assembly. However, it reported that non-linearity due to friction between a shaft and a sleeve had to be considerably analyzed in design and servo system in employing this type of pickup actuator. In this paper, this friction is modeled as a Coulomb's friction and the effect of friction is examined in the simulation. A digital servo system is applied to pickup actuator with friction in order to have good focusing servo. To enhance focusing servo performance using digital servo merit, frist PD-controller is applied to have fast response performance, second lead-lag compensator is applied to have stable focusing performance.

• 한국소음진동공학회논문집
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• 제14권4호
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• pp.287-294
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• 2004

Dynamic Load/unload (L/UL) mechanism is an alternative to the contact start stop (CSS) technology which eliminates striction and wear failure modes associated with CSS. Inertia latch mechanism becomes important for mobile disk drives because of non operating shock performance. Various types of latch designs have been introduced in hard disk drives to limit a rotary actuator from sudden uncontrolled motion. In this paper, a single spring inertia latch is introduced for a small form optical disk drive, which uses a rotary actuator for moving an optical pick-up. A new small inertia latch with sin91e spring is designed to ensure both feasible and small size. The shock performance of the new inertia latch is experimentally verified.

• 로봇학회논문지
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• 제15권1호
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• pp.77-89
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• 2020

This paper proposes a simple and intuitive model-free torque-tracking control for rotary electro-hydraulic actuators. The undesirable natural-velocity-feedback effect is discussed by introducing mechanical impedance into the electro-hydraulic actuation system. The proposed model-free torque control comprises inner- and outer-loop control to achieve two control objectives. Inner-loop control reduces the mechanical impedance passively and optimally. To improve the tracking accuracy, a certain form of proportional-integral-derivative control is applied to the outer loop. The robustness of the proposed closed-loop system against external disturbances is demonstrated by transforming the two-loop control structure into a disturbance observer form. The proposed method is validated on a single joint electro-hydraulic actuator.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.419-424
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• 1996

As track density increases, the effects of nonlinearity in pivot bearing of hard disk drive on the servo performance are becoming more important in considering the range of inertia force and the input torque during settling and tracking mode. Recently, an increasing attention is given to more precise experimental observations and modelings of pivot nonlinearity for achieving higher performance of servo control. In this paper, we propose a new model that shows an improved prediction of the pivot nonlinearity than existing preload-plus-two-slope model at matching simulations and experimental results in both time and frequency domains. Experimental measurements are carried out to validate and identify the specific nonlinearity presents in the pivot bearing when its in fine motion. Using the experimental results new model along with the existing one are characterized and compared for relevancies.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.605-607
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• 2000

Although Equvalent Magnetic Circuit (EMC) method. Using lumped parameter and numerical analysis method are widely used for electric machine analysis. these are neither always accurate enough nor sometimes available to easily use. Moreover three dimensional finite element method (3D-FEM) is inherently unsuitable for electric machine performance evaluation due to its poor computational efficiency, such as too long calculation time and difficulty in modeling for analysis. In this paper, Nonlinear Equivalent Magnetic Circuit (NEMC) method in combination with 2D-FEM is proposed to analyze the electric machine requiring 3D-FEM, and this method applys to torque evaluation for rotary actuator of Electro Magnetic Electronic Controller Power Steering (EM-ECPS).