• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.614-619
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• 1997

The hydraulic pressure pulsation has on the effected on the acoustic nosie and control performance of the hydraulic-servo system. The Helmholtz attenuator introduction on the hydraulic line is an efficient device to reduce the hydraulic pulsation. The salient feature of causing hydraulic pulsation and the frequency characteristics of Helmholtz attenuator are studied. The hydraulic filter design parameters such as the locating position, connecting orifice area and accumulator volume are mathematically analyzed. The instrumental works are carried out with the remarkable reduction of the hydraulic pressure pulsation magnitude and the acoustic noise level.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1062-1070
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• 1995

The study deals with controlling the velocity of hydraulic motor with PI controller through the control of displacement pump which has higher efficiency than valve-controlled system. This was done as follows. First, we modified original displacement pump and designed this electrohydraulic puma system. Second, after experimenting static and dynamic characteristics, we identified system parameter of approximated model. Lastly, to control the velocity of hydraulic motor we controlled the angle of the swash plate of displacement pump. Test carried out in the laboratory shows that transient and steady state response could be improved by PI controller reducing power loss.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.510-515
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• 1993

본 연구에서는 저속에서도 시스템의 자세 제어가 용이하게 하기 위하여 추진기 뒤에 제어판이 위치하도록 설계하였으며, 일반 서보 시스템과는 달리 무게와 공간 제약이 크고, 제어판 운동에 따른 외란 등록성의 변화가 심하므로 push-pull 형태의 소형, 고출력 편로드 복동 복수 실린더의 작동기를 설계하였다. 또한 일반적으로 서보밸브와 작동기는 일체형으로 설계되나 본 시스템의 공간상 심한 제약으로 인하여 서보밸브와 작동기를 분리하는 방법으로 구조설계를 하고 그 사이 유로는 매니폴드식으로 하여 동력전달을 하였다. 설계된 구동장치를 실제 정밀제작하여 실험을 수행하였으며, 시뮬레이션 결과와 실험에 의하여 얻어진 결과를 비교 분석하여 설계의 타당성 및 시스템의 성능을 검증하였다. 고속 수중운동체에 대하여 저속에서 자세제어를 용이하게 하고, 제한된 좁은 설치공간의 문제점을 해결하기 위하여 1) 추진기 후미에 독립된 4개의 상, 하, 좌, 우 제어판 설치 2) 서보밸브는 몸체에, 작동기는 Tail Tube에 분리 작동 설계 3) 소형의 편로드 복동 복수 실린더로 설계 구성된 유압식 구동장치는 시뮬레이션과 실험 결과를 통하여 시스템의 타당성을 입증하였다. 그러므로, 개발한 구동장치는 저속에서도 큰 제어력으로 자세 제어가 용이하기 때문에 얕은 수심에서 발사시 예상되는 위험 요소를 상다ㅇ 개선 시키므로써 운용범위의 다양화를 가져 올것으로 기대된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.581-584
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• 1995

The frequency response of a electro-hydraulic servo(EHS) system is studied. The frequensy response characteristics of the EHS system obtained by linerization method, nonlinerar simulation method, and experimentation are compared ane another. It is found that the frequency response of the EHS is consistent when input signal applied is very small, but that is deviated as input signal becomes large.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.6
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• pp.62-70
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• 2003

This paper deals with a approximation and tracking control of hydraulic servo system using a real time recurrent neural networks (RTRN) with 2-dimensional iterative learning rule. And it was driven that 2-dimensional iterative learning rule in discrete time. In order to control the trajectory of position, two RTRN with same network architecture were used. Simulation results show that two RTRN using 2-D learning algorithm is able to approximate the plant output and desired trajectory to a very high degree of a accuracy respectively and the control algorithm using two same RTRN was very effective to control trajectory tracking of electro-hydraulic servo system.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.1
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• pp.7-14
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• 2006

In this paper, an in-process diagnosis method for performance of position control servo system was studied, which was based upon null bias, slew-rate ratio and delay time measurement. Slew-rate ratio and delay time were analyzed by theoretical analysis, computer simulation and experiment. As a result of these analysis, when spool of servovalve was weared, slew-rate ratio was decreased and delay time was increased.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.103-108
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• 2005

In this paper, a controller design procedure for an electro-hydraulic positioning systems have developed using $H_\infty$ control theory. The generalized models and weighting functions for a multiplicative uncertainty modelling error is presented along with $H_\infty$ controller designs in order to investigate the robust stability and performance. The multiplicative uncertainty case is specifically suited for the design of an electro-hydraulic positioning control systems using $H_\infty$ control.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.710-714
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• 2005

A dynamical analysis and PID control of a compressed gas expulsion system is performed. The purpose of this study is to develop a compressed gas discharging system and to verify the validity of the system. The electro-hydraulic servo valve is modeled as a 3th order transfer function to calculate flow force affecting expulsion valve is significantly considered. The friction force in the expulsion valve is considered as a nonliner model of stribeck effect. The dynamic characteristics of this system is examined by the computer simulation. The position control of the expulsion valve is performed by PID controller.

• Journal of Drive and Control
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• v.13 no.2
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• pp.26-33
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• 2016

This paper describes of a mathematical and real experimental analysis for a walking robot which uses servo valve driven hydraulic actuator. Recently, many researchers are developing a walking robot based on hydraulic systems for the difficult and dangerous missions such as walking in the rough terrain and carrying a heavy load. In order to design and control a walking robot, the characteristics of the hydraulic actuators in the joint through the view point of walking such as controllability and backdrivability must be analyzed. A general mathematical model was used for analysis and proceeds to position and pressure changes characteristic of the input and backdrivability experiment. The result shows the actuator is a velocity source, had a high impedance, the output stiffness is high in contact with the rigid external force. So stand above the controller and instruments that complement the design characteristics can be seen the need to apply a hydraulic actuator in walking robot.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.231-234
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• 1998

In this paper, we proposed a adaptive controller which need not adjustment of the scale factor. We have verified by experimental results that applying this proposed adaptive control algorithm to a hydraulic servo system is very satisfactory.