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ER 밸브 작동기를 이용한 하역시스템 모델의 슬라이딩모드 제어
최승복,김형석,정달도,성금길,Choe, Seung-Bok,Kim, Hyeong-Seok,Jeong, Dal-Do,Seong, Geum-Gil 대한기계학회 1999 大韓機械學會論文集A Vol.23 No.11
This paper presents a novel concept of cargo handling system adapted for a sea port subjected to severe time-varying tide. The proposed system can perform loading or unloading by using a sort of hydraulic elevator associated with real-time position control. In order to achieve a proof-of-concept, a small-sized laboratory model of the cargo handling system is designed and built. The model consists of three principal components container palette transfer (CPT) car, platform with lifting columns, and cargo ship. The platform activated by electro-rheological (ER) valve-cylinders is actively controlled to track the position of the cargo ship subjected to be varied due to the time-varying tide and wave motion. Following the derivation of the dynamic model for the platform and cargo ship motions, an appropriate control scheme is formulated and implemented. The location of the CPT car is sensed by a set of photoelectric switches and controlled via sequence controller. On the other hand, a sliding mode controller (SMC) is adopted as the position controller for the platform. Both simulated and measured control results are presented to demonstrate the effectiveness of the proposed cargo system.
박우철,안종국,정달도 三陟大學校 1998 論文集 Vol.31 No.1
This paper presents durability charateristics of electrorheological(ER) fluids which ungergo a reversible phase change depending upon the impositon of electric fields. The field--dependent Bingham properties are subjected to be altered from long time use of the ER fluid. A piston-rod system which has same mechanism as ER dampers is adopted in this study and tested by increesaing operation cycle up to 1 million. Bingham properties of initial and used ER fluids are tested and compared.
이중근,박우철,이현창,정달도 三陟大學校 2001 論文集 Vol.34 No.1
In this paper, the transmitted noise reduction of piezoelectric smart panels is experimentally studied. The proposed piezoelectric smart panels are comprised of plate structure on which piezoelectric sensor/actuators are bonded and sound absorbing material and/or gap are provided. It is a combination of passive and active approaches utilizing a passive effect at high frequencies and active effect at low frequencies. To prove the concept of piezoelectric smart panels, and acoustic measurement experiment is performed. An acoustic tunnel is designed and its acoustic characteristics are tested. Below 800㎐, the tunnel exhibits a plane wave guide characteristics. When an absorbing material is bonded on a single plate, a remarkable transmitted noise reduction in mid frequency range is observed except the first resonance frequency. By enabling the active control of smart single panel, much noise reduction is achieved at the resonance frequencies. The smart double panel has more potential to reduction the transmitted noise in wide range frequency. Piezoelectric smart panels incorporating passive absorbing material and active piezoelectric devices is a promising technology for noise reduction in a wide range frequency.
김준혁(Kim, Jun Hyuk),김재환(Kim, Jaehwan),정달도(Chung, Dal Do) 한국소음진동공학회 2005 한국소음진동공학회 논문집 Vol.15 No.4
In this paper, a new type of pi+ezoelectric stepping motor is designed, manufactured and tested. This motor is composed of piezoelectric torsional actuator and a pair of one-way clutch bearings. The torsional actuator consists of 16-polygonal tube of piezoceramic that can produce an angular displacement associated with shear mode. One-way clutch bearing converts oscillation of torsional actuator into a continuous stepping rotation. The proposed stepping motor does not require any conversion mechanism for stepping motion like any other motors. In the design process, the shear resonance mode of piezoelectric actuator is analyzed by using a commercial finite element analysis program, and the performance of the fabricated torsional actuator is measured. $0.124^{\circ}$ of maximum angular displacement is measured in square wave excitation on the actuator only. The stepping motor is manufactured by assembling a pair of one-way clutch bearings and the torsional actuator. The maximum rotation speed of 72rpm and the blocking torque of 3.136 mNm are measured at 3540 Hz and 100V/mm. Once the proposed piezoelectric stepping motor is miniaturized, it can be used for many compact and precise moving applications.