Output characteristics of a horizontal type electro-hydraulic excitation system with inertial loading: Modeling and experimentation

Ren Yan,Ji Xiancheng,Ruan Jian 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

In a conventional electro-hydraulic excitation system it is difficult to realize high frequency vibration, even though at the cost of a decreased hydraulic force. A 2D rotary valve, characterized by the spool’s simultaneous rotary and sliding motions, was improved and adopted in a horizontal type electro-hydraulic excitation system in order to improve its high frequency performance. A description of vibration characteristics is still a challenge for the excitation system with inertial loading subjected to high frequency excitation. Therefore, this paper investigated the output characteristics of this electro-hydraulic excitation system in detail. A mass force dominant excitation system was taken as an example to demonstrate those output characteristics, which was facilitated by a specially designed approximate phenomenological model. Based on this model, the analytical expressions of the excitation waveform, working frequency and some boundary values were derived and subsequently shown to be in line with the experimental data. Theoretical and experimental results indicate that the output excitation waveforms could be described using the analytical expressions, even though the measured waves demonstrate different distortions. The distortions are especially obvious when the operating frequencies are below the resonant frequency, while they are attenuated as the frequencies increase beyond the resonance. This noteworthy phenomenon is one of the manifestations of hydraulic resonance. These results and findings provide clear guidance for the understanding and designing of the electro-hydraulic excitation system with high frequency feature.

A Hybrid Fault Diagnosis Approach for Hydraulic Systems by using Radial basis Function Networks

Xiang-yu He,Yijiao Yang,Shanghong He 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.12

To improve the reliability of hydraulic systems, a fault diagnosis approach based on radial basis function (RBF) networks was proposed in this paper. According to the target fault features extracted from a fuzzy auto-regressive with extra outputs (FARX) model, RBF networks serve as a fault classifier and the output of the RBF networks is the result of fault diagnosis. Several typical faults of hydraulic systems were used to test the fault diagnosis approach. Experiment results showed that the fault diagnosis approach is feasible and effective for improving the reliability of hydraulic systems.

무대장치용 유압서보시스템의 출력 피드백 제어기 설계

원대희(Won Daehee) 한국정밀공학회 2013 한국정밀공학회 학술발표대회 논문집 Vol.2013 No.5월

On-cam operation of counter-rotating type hydroelectric unit

Tetsuro Kasai,Makoto Usui,Yoshihiro Nakamura,Toshiaki Kanemoto,Daisuke Tanaka 한국물리학회 2010 Current Applied Physics Vol.10 No.2

To cope with the warming global environments, the authors had proposed the counter-rotating type hydroelectric unit, which is composed of the tandem runners and the peculiar generator with double rotational armatures. This unit can be supplied to various water circumstances, for instance, the traditional large hydropower, the mini/micro hydropower, and the tidal power. The fundamental performances and the flow conditions around the runners have been investigated and the design materials for the runners have been presented. Continuously, this paper discusses the performances at the oncam operation, in the large tidal power station. The model unit was operated while keeping the relative rotational speed constant nT = 900 min-1, namely 60 Hz, irrespective of the hydropower circumstances. The output and the hydraulic efficiency are affected by the blade setting angles of the front and the rear runners. Resultantly, both optimum angles giving the maximum output and/or the maximum efficiency are presented at the various discharges/heads.

Sliding Mode Robust Control of Hydraulic Drive Unit of Hydraulic Quadruped Robot

Rui Zhu,Qingjun Yang,Yudong Liu,Rizhi Dong,Chunli Jiang,Jiaxing Song 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.4

This paper focuses on the position control of the quadruped robot hydraulic drive unit (HDU). The proposed control strategy has the advantages of excellent output tracking performance, strong robustness, no chattering and low computational complexity. HDU has the characteristics of nonlinearity and parameter uncertainty, coupled with unpredictable external interference, which makes it difficult to achieve precise position control. In this paper, we first establish the mathematical model of the HDU based on the actual parameters and obtain the state space of the system. Through the pole placement, the simplified system can easily achieve the expected control goal. Then, the state equation of the error system is constructed, and the nonlinearity, parameter uncertainty and external interference of the HDU are summarized as the matched and unmatched uncertainties of the system. The integral sliding mode control (ISMC) is used to derive the control law, and the response characteristics of the system when pole placement and state feedback H∞ control are used for the nominal control are compared. It can be concluded that the system with state feedback H∞ control for nominal control has stronger robustness and can resist the unmatched uncertainties. Finally, the control law of the simplified system is used as feedforward and combined with the ISMC of the error system, the output tracking control framework of the HDU is proposed. Simulations and experiments show that the proposed control method has excellent tracking performance and strong robustness.

단일입력 다출력 PTO Gearbox의 토크 특성에 관한 연구

이용범(Yong Bum Lee),유한주(Han Ju Yoo),김태석(Tae Seok Kim) 대한기계학회 2018 大韓機械學會論文集A Vol.42 No.2

유압식 굴삭기는 가장 많이 사용되는 건설기계 중 하나로, 초 대형급 굴삭기의 수요도 점차 늘어나고 있는 추세이다. 초 대형급 굴삭기는 연비효율 개선을 목적으로 주 엔진과 다수의 펌프사이에 PTO 기어박스를 장착하고 있다. PTO(Power Take Off) 기어박스의 출력축은 3대의 펌프와 연결되어 펌프의 작동에 따라 부하를 받으므로, 각 출력 축 마다 발생되는 정격 부하가 다르다. 본 논문에서는 전기식 다이나모메터를 이용한 부하제어 방식을 적용하고, PTO 기어박스의 각 출력축에 기계적인 비틀림으로 토크를 분배하는 기술을 소개하며, 그 특성에 대해서 고찰하였다. Hydraulic excavator is one of the most commonly used construction equipments. In addition, the demand of large excavator has been increased. PTO gearbox, installed between engine and pumps, is used to improve fuel efficiency of large excavator. Because the PTO gearbox is loaded by the pump mounted on the output shaft, the torque distribution technique should be applied when controlling the load with the dynamometer. This paper introduces a torque distribution technique and conducts a comparative analysis of the torque test results and dynamic analysis.

The Performance Analysis of a Counter-rotating Tubular Type Turbine with the Number of Runner Vane

박지훈(Park, Jihoon),이낙중(Lee, Nakjoong),황영호(Hwang, Youngho),김유택(Kim, Youtaek),이영호(Lee, Youngho) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06

Micro hydraulic turbines take a growing interest because of its small and simple structure as well as high possibility of applying to micro and small hydropower resources. The differential pressure exiting within the city water pipelines can be used efficiently to generate electricity like the energy generated through gravitational potential energy in dams. In order to reduce water pressure at the inlet of water cleaning centers, pressure reducing valves are used widely. Therefore, pressure energy is wasted. Instead of using the pressure reduction valve, a micro counter-rotating hydraulic turbine can be replaced to get energy caused by the large differential pressure found in the city water pipelines. In this paper, detail studies have been carried out to acquire basic design data of micro counter-rotating hydraulic turbine, output power, head, and efficiency characteristics on various number of runner vane. Moreover, the influences of pressure, tangential and axial velocity distributions on turbine performance are also investigated.

가스보조식 이중행정 유압브레이커의 성능 최적화

류택직(Taek Jik Ryoo),장효환(Hyo Whan Chang) 유공압건설기계학회 2010 드라이브·컨트롤 Vol.7 No.1

A gas-assisted hydraulic breaker uses both hydraulic and pneumatic energies and the appropriate balance between them mostly effects its performance. Mathematical modeling of the breaker is established and verified by experiment. Through sensitivity analysis using AMESim, the key design parameters are selected, which mostly affect the performance of the breaker. Taguchi method is used to optimize the key design parameters to maximize the output power for long and short strokes through simulation. As the result, the output power as well as the impact energy are increased significantly compared with the existing design. The pressure pulsation in the supply line is reduced to a tolerable level and the dynamic characteristics of the piston displacement is also improved by the optimization.

단일입력 다출력 PTO 기어박스의 내구성시험에 관한 연구

이용범(Yong Bum Lee),유한주(Han Ju Yoo) 유공압건설기계학회 2017 드라이브·컨트롤 Vol.14 No.1

This study analyzed a life test method for a power take-off (PTO) gearbox. An engine transfers mechanical power (rotation and torque) to a hydraulic pump through a PTO Gearbox with one input shaft and three output shafts. PTO gear box durability under high loads over long time periods was tested using dynamometers. In order to reflect the rated operating conditions, power must be distributed to each output shaft, and experiments were conducted under various conditions to verify the characteristics of the distributed power. An accelerated life test was designed using speed and torque as acceleration factors. Also, efficiency tests were conducted under various load conditions. Also, a lubrication oil composition analysis was performed to analyze gearbox wear status.

가스보조식 이중행정 유압브레이커의 성능 최적화

류택직,장효환 사단법인 유공압건설기계학회 2010 드라이브·컨트롤 Vol.7 No.1

가스보조식 유압브레이커는 굴삭기에서 공급되는 유압에너지와 유압브레이커 상부에 있는 백헤드가스실의 공압에너지를 피스톤의 운동에너지로 변환하고, 변환된 운동에너지는 툴(tool)을 통하여 타격물에 전달되어 타격물을 파쇄하는 기계장치이다. 이중행정(dual stroke)유압브레이커는 긴 행정과 짧은 행정으로 구성되어 있으며, 긴 행정은 큰 타격에너지를 필요로 하는 단단한 지반에, 짧은 행정은 큰 타격수를 필요로 하는 무른 지반에 사용된다. 가스보조식 유압브레이커에 대한 연구는 상당수 진행되었지만, 체계적인 설계변수 민감도 해석과 이중행정을 고려한 성능향상에 대한 연구는 없는 실정이다. 본 연구에서는 가스보조식 이중행정 유압브레이커에 대하여 수학적 모델을 수립하고 AMESim을 이용한 시뮬레이션에 의해 성능을 해석하였으며, 실험을 통해 타당성을 검증하였다. 민감도해석을 통하여 유압브레이커의 설계변수들이 성능에 미치는 영향을 규명하고 주요 설계변수들을 추출하였다. Taguchi 방법을 적용하여 유압브레이커의 출력을 최대화하는 설계변수들의 최적값을 구하였고 기존설계와 성능을 비교하였다. A gas-assisted hydraulic breaker uses both hydraulic and pneumatic energies and the appropriate balance between them mostly effects its performance. Mathematical modeling of the breaker is established and verified by experiment. Through sensitivity analysis using AMESim, the key design parameters are selected, which mostly affect the performance of the breaker. Taguchi method is used to optimize the key design parameters to maximize the output power for long and short strokes through simulation. As the result, the output power as well as the impact energy are increased significantly compared with the existing design. The pressure pulsation in the supply line is reduced to a tolerable level and the dynamic characteristics of the piston displacement is also improved by the optimization.