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장중걸(Z. J. Zhang),김도태(D. T. Kim),한신식(S. S. Han) 유공압건설기계학회 2010 유공압건설기계학회 학술대회논문집 Vol.2010 No.6
Nonlinear seal friction in pneumatic cylinders can impede the performance of pneumatic systems designed for high precision positioning with favorable high speed actuation. The behaviour of an elastomeric piston seal in high speed pneumatic cylinders is analysed by nonlinear finite element analysis using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the piston seal are simulated with variation of interference fits, supply pressures, friction coefficients and piston rod velocities. The nonlinear finite element model of the piston seal is used to predict deformation of a seal, friction force and contact pressure distributions.
장중걸(Z. J. Zhang),김도태(D. T. Kim),한신식(S. S. Han) 유공압건설기계학회 2008 유공압건설기계학회 학술대회논문집 Vol.2008 No.10
A cushion is used to decelerate the motion of pneumatic cylinder at the end of its stroke to reduce or eliminate noise, to prevent the destruction of the cylinder or external parts, and requce vibration and impact. This paper presents a simulation model of a double-acting pneumatic cylinder with a relief valve type cushion mechanism. This model predicts piston motion, mass flow rate, pressure and temperature time histories. Of interest here is to investigate the effect of cushion ring diameter and length, piston and rod diameter, stroke, supply pressure and relief valve pressure setting.
장중걸(Z. J. Zhang),김도태(D. T. Kim),주민진(M. J. Joo) 유공압건설기계학회 2011 유공압건설기계학회 학술대회논문집 Vol.2011 No.6
The paper deals with the design of a new low-friction seal for a pneumatic cylinder with high speed actuation. The seal performance with variation of the cross sections in piston seals with elastomeric material was investigated to minimize the friction forces using ABAQUS. The contact pressures, stress and strain distributions and frictional forces of the piston seals were investigated with variation of interference fits, supply pressures, friction coefficients. To develop adequate and productive procedures, the finite element models of the piston seals were created and nonlinear analysis of a seal design was conducted in order build further knowledge and understanding of the seal"s performance characteristics.
김도태,장중걸,한신식 한국공작기계학회 2009 한국공작기계학회 춘계학술대회논문집 Vol.2009 No.-
Pneumatic cushion cylinders are most widely used as actuators in automatic equipment because they are relatively inexpensive, simple to install and maintain, offer robust design and operation, are available in a wide range of standard sizes and design alternatives. Compressed air is a very expensive form of energy and therefore systems have been proposed to conserve pneumatic energy which mostly means lowering the supply pressure. The purpose of this paper is to compare meter-out and meter-in speed control of high speed pneumatic cushion cylinder. A mathematical simulation model of a double acting pneumatic cushion cylinder used the relief valve type is presented. The dynamic characteristics in the horizontally-mounted pneumatic cylinder, the meter-out and meter-in speed control are investigated with variation of the supply pressure, total mass, effective area of flow control valve, cracking pressure of relief valve, piston rod diameter, stroke, cushion sleeve length etc.
김도태(D. T. Kim),장중걸(Z. J. Zhang),주민진(M. J. Joo) 유공압건설기계학회 2012 유공압건설기계학회 학술대회논문집 Vol.2012 No.6
The paper describes a technique that compensates a friction in pneumatic cylinder to perform the position control. The friction is one of the most common nonlinearities present in pneumatic actuating systems. For accurate position control and low velocity control, control strategies usually rely on accurate estimation of friction. This paper presents a observer to estimate the friction force in the pneumatic cylinder from the pressures in cylinder chambers. Also, the stiction compensation of a pneumatic cylinder is obtained by adding pulses to the control signal using impulsive control. The characteristics of the pulses in impulsive control are determined from the control action. The simulation results are proved that the method proposed here is effective.
공기압 실린더 고속 구동시스템에서 파라미터 변화에 따른 쿠션성능 비교
김도태(Do Tae Kim),장중걸(Zhong Jie Jang) 유공압건설기계학회 2015 드라이브·컨트롤 Vol.12 No.4
Due to the tendency to use high speed pneumatic cylinders to improve productivity, cushioning devices are adopted to decelerate the piston motion of pneumatic cylinders to reduce noise, vibration, and impact. This paper presents a comparison of the cushion characteristics of a high speed pneumatic cylinder with a relief valve type cushioning device. The system parameters selected are the damping coefficient, Coulomb friction, heat transfer coefficient, and cracking pressure of the relief valve in the air cushioning device. The integral of the time multiplied square error (ITSE) is used to quantitative measure the cushioning performance to assess the effect of varying these. The cushioning performance achieved good results when the ITSE is a minimum value. In a comparison of the piston displacement and velocity with the variations in system parameters, the heat transfer coefficients are not as significantly affected as the other. Also, the cracking pressure of the relief valve is mainly affected by the pressure and temperature in the cushion chamber.