릴리프밸브 쿠션기구 내장형 공기압 실린더의 구동 특성

김도태,Kim, Do Tae 유공압건설기계학회 2016 드라이브·컨트롤 Vol.7 No.4

This paper presents the meter-out and meter-in speed control characteristics of a pneumatic cylinder with relief valve type cushion device. The piston displacement and velocity are measured to investigate high speed driving performance with variation of the pressure setting in relief valve, air supply pressure, load mass, the supply and exhaust flow rate from the cylinder. Also, the internal pressures and temperatures driving pressure and cushion chamber are measured. The piston displacements and velocities of meter-out and meter-in control are compared experimentally determined data. A comparison experimental data meter-out and meter-in control show that a relief valve type cushion device is suitable for high speed pneumatic cylinders. The desired response characteristics of piston displacement and velocity are satisfactory adjust the pressure setting of a relief valve with varying system parameters such as air supply pressure, load mass and controlled flow rate.

유압전동장치(HST)의 압력맥동 특성

김도태(Do-Tae Kim),윤인균(In-Gyun Yun) 한국생산제조학회 1998 한국공작기계학회 추계학술대회논문집 Vol.1998 No.-

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.

고속 공기압 쿠션 실린더의 설계에 관한 연구

김도태(Do-Tae KIM),김동수(Dong-Soo KIM),주민진(Min-Jin JU) 한국생산제조학회 2009 한국생산제조학회지 Vol.18 No.5

Of all of pneumatic components utilized in the make up of pneumatic circuits on either automatic assembly machine or industrial equipment, the pneumatic cylinder is more oriented toward being a structural as well as a pneumatic member. The structural design must be based to a large degree on the end of application of the cylinder on the equipment it is operating. In this paper, design studies of a double-acting pneumatic cushion type cylinder with low-friction and high-speed driving have been developed. Of interest here is to investigate the stress and strain analysis of cylinder tube, piston rod, end cover, and to analyze the buckling of piston rod. A finite element analysis is carried out to compute the distribution of the displacement, stress and safety factors by using ANSYS. As a result, the structural safety factors of each parts in pneumatic cushion cylinder are evaluated and confirmed at the design specifications.

분포정수계 관로모델을 이용한 비정상 유량계측

김도태(Do-Tae Kim),홍성태(Sung-Tae Hong) 한국생산제조학회 2008 한국생산제조학회지 Vol.17 No.3

The paper proposes a model-based measurement of unsteady flow rate by using distributed parameter pipeline model and the measured pressure values at two distant points along the pipeline. The distributed parameter model of hydraulic pipeline is applied with consideration of frequency dependent viscosity friction and unsteady velocity distribution at a cross section of a pipeline. By using the self-diagnostics functions of the measurement method, the validity is investigated by comparison with the measured and estimated pressure and flow rate wave forms at the halfway section on the pipeline. The results show good agreement between the estimated flow rate wave forms and theoretical those under unsteady laminar flow conditions. The method proposed here is useful in estimating unsteady flow rate through an arbitrary cross section in hydraulic pipeline and components without installing an instantaneous flowmeter.

고속 공기압 쿠션 실린더의 설계에 관한 연구

김도태,김동수,주민진,Kim, Do-Tae,Kim, Dong-Soo,Ju, Min-Jin 한국생산제조학회 2009 한국생산제조학회지 Vol.25 No.1

Of all of pneumatic components utilized in the make up of pneumatic circuits on either automatic assembly machine or industrial equipment, the pneumatic cylinder is more oriented toward being a structural as well as a pneumatic member. The structural design must be based to a large degree on the end of application of the cylinder on the equipment it is operating. In this paper, design studies of a double-acting pneumatic cushion type cylinder with low-friction and high-speed driving have been developed. Of interest here is to investigate the stress and strain analysis of cylinder tube, piston rod, end cover, and to analyze the buckling of piston rod. A finite element analysis is carried out to compute the distribution of the displacement, stress and safety factors by using ANSYS. As a result, the structural safety factors of each parts in pneumatic cushion cylinder are evaluated and confirmed at the design specifications.

릴리프밸브 쿠션기구 내장형 공기압 실린더의 구동 특성

김도태(Do Tae Kim) 유공압건설기계학회 2016 드라이브·컨트롤 Vol.13 No.4

This paper presents the meter-out and meter-in speed control characteristics of a pneumatic cylinder with relief valve type cushion device. The piston displacement and velocity are measured to investigate high speed driving performance with variation of the pressure setting in relief valve, air supply pressure, load mass, the supply and exhaust flow rate from the cylinder. Also, the internal pressures and temperatures driving pressure and cushion chamber are measured. The piston displacements and velocities of meter-out and meter-in control are compared experimentally determined data. A comparison experimental data meter-out and meter-in control show that a relief valve type cushion device is suitable for high speed pneumatic cylinders. The desired response characteristics of piston displacement and velocity are satisfactory adjust the pressure setting of a relief valve with varying system parameters such as air supply pressure, load mass and controlled flow rate.

분포정수계 유압관로 모델의 동특성 해석

김도태(Do Tae Kim) 유공압건설기계학회 2018 드라이브·컨트롤 Vol.15 No.4

The paper deals with an approach to time domain simulation for closed end at the downstream of pipe, hydraulic lines terminating into a tank and series lines with change of cross sectional area. Time domain simulation of a fluid power systems containing hydraulic lines is very complex and difficult if the transfer functions consist of hyperbolic Bessel functions which is the case for the distributed parameter dissipative model. In this paper, the magnitudes and phases of the complex transfer functions of hydraulic lines are calculated, and the MATLAB Toolbox is used to formulate a rational polynomial approximation for these transfer functions in the frequency domain. The approximated transfer functions are accurate over a designated frequency range, and used to analyze the time domain response. This approach is usefully to simulate fluid power systems with hydraulic lines without to approximate the frequency dependent viscous friction.

북미 핵 협상 : 북한의 협상 태도 변화와 미국의 선택

김도태(Do Tae Kim) 북한대학원대학교 2003 현대북한연구 Vol.6 No.2

공기압 쿠션 실린더의 미터아웃/미터인 속도제어 특성에 관한 연구

김도태(Do-Tae Kim) 한국생산제조학회 2013 한국생산제조학회지 Vol.22 No.1

Pneumatic cylinders are widely used to actuators in automatic equipments 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. This paper presents a comparative study among the dynamic characteristics of meter-out and meter-in speed control of pneumatic cushion cylinders with a relief valve type cushion mechanism. Because of the nonlinear differential equations and a requirement for simultaneous iterative solution in a mathematical model of a double acting pneumatic cushion cylinder, a computer simulation is carried out to investigate pressure, temperature, mass flow rate in cushion chamber and displacement and velocity time histories of piston under various operating conditions. It is found that the piston velocity and pressure response in meter-in speed control are more oscillatory than with meter-out those when pneumatic cushion cylinders are driven at a high-speed. In meter-out speed control, the effective area of the flow control valve is larger than that of meter-in, and the supply pressure has to be much higher than the pressure required to move the load because it has also to overcome the back pressure in cushion chamber.