• 대한기계학회논문집
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• 제13권2호
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• pp.213-220
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• 1989

본 연구에서는 고정도의 위치제어계를 실현하기 위하여 가변구조제어이론을 전기-유압서보계에 적용하였다.실험은 유압구동부의 공급압력을 변화시켜 유압계의 매개변수를 변화시켜줄 때와 관성하중을 가감하여 부하를 변화시켜 가며 행하였다. 가변구조계에서는 계의 매개변수변동과 부하변동에도 영향을 받지 않음을 종래의 고정구조계와 구조계와 비교, 검토하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1611-1616
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• 1991

A high power stewart platform is designed and manufactured to simulate the 6 degrees of freedom motion of moving vehicle. This paper describes the design of such a motion system including kinematic and kinetic analysis, real time servo control mechanical and hydraulic system configuration, and techniques of regeneration of test records. Discussions are also presented for an algorithm called remote parameter control, which has been developed to compensate the dynamic delay of the electro-hydraulic servo actuators and the nonlinearities of stewart platform.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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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.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.276-281
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• 1989

Comparison 3-port servo system with 4-port is made to obtain optimal design for heavy and unidirectional hydraulic system, It is concluded that 3-port servo system it more adequate than 4-port for the heavy load system which is usually operated at lower frequencies. High performance electro-hydraulic position controller is designed using 3-port servo valve. It includes dynamic pressure feedback as a inner loop and position feedback as a outer loop.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1576-1577
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• 2007

As a intelligent valve piezoelectric valve is to applied to various fields of application. Piezoelectric valves have fast response time and good linearity for pressure control but its hysteresis displacement by its stack actuator influences on pressure control in electro-hydraulic braking. Solenoid valves are traditional element to control hydraulic pressure but this paper proposes piezoelectric valve for brake pressure control with hysteresis compensation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.1002-1007
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• 2010

This study evaluates the electro-osmotic hydraulic conductivity for the clay specimen by applying the series of the voltage gradient simultaneously with different stress conditions. The test results shows that the shrinkage of voids corresponds to the linear decrease in the electro-osmotic seepage velocity, and the changes of electro-chemical characteristics in the specimen induces the gradual decrease of the electro-osmotic seepage velocity with the constant voltage gradient.

• 한국정밀공학회지
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• 제20권8호
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• pp.94-100
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• 2003

This paper presents the experiments on the approximation of a hydraulic servo system using a real time recurrent neural networks (RTRN) with time varying weights. In order to verify the effectiveness of the RTRN algorithm in hydraulic servo system, we design the experimental hydraulic system and implemented the real time approximation of system output. Experimental results show that approximated output of the RTRN well follows the position trajectory of the electro-hydraulic servo system. And also it is verified that the 2-D RNN can be implemented in sampling time even though high sampling frequency experimentally.

• 드라이브 ㆍ 컨트롤
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• 제16권4호
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• pp.1-8
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• 2019

The HPM (High-speed Power Matching) system is an electro-hydraulic control system. It directly controls the swash plate of the pump by selecting four-loop logic based on joystick signals, pump flow, and pressure signal to improve the efficiency and controllability of construction machines. In the NFC (Negative Flow Control) system, a typical pump control system using conventional open center type MCV, the loss is continuously generated by flow through the center bypass line even when the excavator is not in operation. Also, due to the slow response of the pump that indirectly controls the flow rate using the pressure regulator, peak pressure occurs at the start or stop of the operation. Conversely, the HPM system uses an MCV without center-by-pass flow path and the swash plate of a pump for the HPM is controlled by a high-speed proportional flow control valve. As a result, the HPM system minimizes energy loss in standby state of the excavator and enables peak pressure control through rapid electro-hydraulic control of a pump. In this paper, the concept of the HPM system algorithm is introduced and the hydraulic system efficiency is compared with the NFC system using the excavator SAT (System Analysis Tool).

• 한국항공우주학회지
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• 제35권4호
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• pp.316-322
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• 2007

정유압 방식 EHA는 종래의 밸브 제어 방식 전기유압 구동장치와 전혀 다른 특성을 나타낸다. 본 논문에서는 EHA의 비선형 요소를 포함한 수학적 모델을 유도하고 실험적으로 검증하였다. 이 수학적 모델을 근거로 전기 모터로 구동되는 유압 펌프, 파이프 배관 그리고 유압 실린더로 구성되는 EHA의 시물레이션 모델을 개발하여 주요 설계 인자인 모터 토크의 피크치, 펌프의 관성 모멘트 등이 제어 성능에 미치는 영향을 분석하였다. 여기에서 실험 조건은 의도적으로 과도기에서 모터 토크가 포화되도록 선정하였다. 그 결과로서 최대 속도로 동작하는 EHA의 제어 정밀도를 개선하기 위한 설계 조건을 조사하였다.

• 한국정밀공학회지
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• 제21권1호
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• pp.101-108
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• 2004

An electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and its parameter fluctuations are greater than those of an electrically driven manipulator. So it is relatively difficult to obtain stable control performance. In this report, we applied disturbance estimation and compensation type robust control to all axes in a 3-link electro-hydraulic manipulator. From the results of experiment, it was confirmed that the performance of trajectory tracking and attitude regulating is greatly improved by the disturbance observer, which model is the same for each axis. On the other hand, for the autonomous assembly tasks, it is said that compliance control is one of the most available methods. Therefore we proposed compliance control which is based on the position control by disturbance observer for our manipulator system. To realize more stable contact work, the states in the compliance loop are feedback, where not only displacement but also velocity and acceleration are considered. And we applied this compliance control to Peg-in-Hole insertion task and analyzed mechanical relation between peg and hole. Also we proposed new method of shifting the position of end-effector periodically for the purpose of smooth insertion. As a result of using this method, it is experimentally confirmed that Peg-in-Hole insertion task with a clearance of 0.05［mm］can be achieved.