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An Optimal controller for an Electro-hydraulic System |
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Dang Xuan Ba, Kyoung Kwan Ahn(University of Ulsan, Korea) |
| In this paper, an advanced controller is presented for position tracking control and minimizing control energy of an electro-hydraulic system. An index function is first formulated for the closed-loop performance. The optimal control input is then calculated based on the Taylor series expansion of the index function. For providing information to the control design, mathematical model of the EHS is also derived. Finally, effectiveness of the proposed controller is successfully validated through experimental results of different testing conditions. |
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Study on Energy Regeneration of Hybrid Hydraulic Excavator using Hydraulic Transformer |
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Yingxiao Yu, Kyoung Kwan Ahn(Uinversity of Ulsan, Korea) |
| Regeneration of the potential energy is an effective solution to save energy. However, the conventional hybrid excavator can’t regenerate the potential energy. This paper proposes a new structure of hydraulic excavator as well as a control strategy. The focus of the paper is using hydraulic transformer to regenerate energy. The simulation is carried out by the AMESim software. From the simulation results, this new system has a high efficiency for energy saving. |
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Hydraulic Circuit Analysis for the Electro-Hydrostatic Actuator System |
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So-Nam Yun, Jung-Ho Park(Korea Institute of Machinery & Materials, Korea), Choong-Mok Yoo(Sewon cellontech, Korea) |
| An Electro-Hydrostatic Actuator(EHA) is a kind of a closed loop system using bi-directional hydraulic pump and cylinder assembly, and is used to control the position of the aircraft and the missile.
In this study, a development research of an arm cylinder of an excavator which has some valves, a bi-directional hydraulic pump, an auxiliary power assister and a generator with a hydraulic motor is conducted, and an arm cylinder is controlled by closed loop method. Also, the possibility of the EHA system for the next generation excavator is discussed and estimated using SimulationX software.
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A study on modeling of a hybrid wind wave energy converter system |
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Tri Dung Dang, Kyoung Kwan Ahn(University of Ulsan, Korea), Phan Cong Binh(Ulsan University, Korea) |
| A model of a hybrid wind wave energy converter (HWWEC) system is proposed in this paper. The HWWEC includes two wave buoys and a vertical axis wind turbine (VAWT) system, which co-works to drive a generator. Wave buoys are arranged in an arc pattern to capture efficiently wave energy from many directions. The hydrodynamic forces are calculated by the Wave Analysis at Massachusetts Institute of Technology WAMIT software. In order to bring the system into resonance with the incident wave frequencies, a variable inertia hydraulic flywheel is employed so that the power output is maximized. |
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Adaptive Grey Predictor-based Controller for Force Control of EHA System |
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Thanh Liem Dao, Kyoung Kwan Ahn(University of Ulsan, Korea) |
| This study aims to develop an effective control approach a typical EHA system. This control scheme is combination of a feedforward neural network – based PID controller and a fuzzy grey predictor (FGP), FNNFGP. Here, the FNNPID controller is used to drive the system to desired targets. Meanwhile, the FGP predictor takes part in, first, estimating the system output in the near future to optimize the controller parameters in advance and, second, creating a compensating control signal accordingly to the system perturbations and, consequently, improving the control performance. |
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