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Kim, Chi-Hyo;Park, Kun-Woo;Kim, Tae-Sung;Lee, Min-Ki
- Transactions of the Korean Society of Mechanical Engineers A
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- v.35 no.3
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- pp.299-308
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- 2011
In this study, we develop a pressure observer to measure the cylinder length of a harbor-construction robot. For the robot control, sensors are required to measure the length of a hydraulic cylinder. The cylinder-position sensor is relatively expensive when the operating environment prohibits external approaches for the measurement of the cylinder position. LVDT or linear scales are usually mounted on the outside of the cylinder, which causes poor durability on a construction site. We use a pressure sensor to indirectly estimate the length of the cylinder. The pressure sensor is mounted inside a hydraulic valve box so that it is protected by the box and easy to waterproof for an underwater robot. By treating oil as a compressible fluid, we derive the nonlinear pressure dynamics as a function of the cylinder position, velocity, and pressure. The recursive least squares (RLS) algorithm is applied to identify the dynamic parameters, and the pressure observer estimates the cylinder position through the pressure acting on the head and the rod of the hydraulic cylinder. The position accuracy is relatively low, but it is acceptable for a construction robot that handles large armor stones.
https://doi.org/10.3795/KSME-A.2011.35.3.299 인용 PDF KSCI

Kim, Chi-Hyo;Kim, Tae-Sung;Lee, Min-Ki
- Journal of Navigation and Port Research
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- v.36 no.10
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- pp.865-871
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- 2012
This paper presents an observer to estimate the displacement of hydraulic cylinders of an underwater robot for harbour construction using a pressure sensor. In harbour constructing, we place heavy armour stones weighing over 2~3 tons on the surface of the bank to protect it from storming wave. This work typically done by a diver is difficult and dangerous so that we have developed Stone Diver which is the underwater robot for harbour construction. The robot needs a displacement sensors to control the position of hydraulic cylinders. The position sensors mounted outside the cylinders cause poor durability in construction site where shock and dust usually occur. However, the pressure sensor mounted inside a waterproof box improves the durability. Based on the dynamic parameters and the pressures in the cylinder, the observer estimates the cylinder's position. This paper presents the positional accuracy of the pressure based observer and the performance of the underwater robot to assemble the armour stones.
https://doi.org/10.5394/KINPR.2012.36.10.865 인용 PDF KSCI

Kim, Jin-Tak;Park, Sang-Sin;Han, Sang-Cheol;Kim, Jin-Hyeon;Jo, Jeong-San
- Journal of Drive and Control
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- v.17 no.4
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- pp.31-37
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- 2020
We are concerned with the dual-arm manipulation for disaster-responding special-purpose machinery. This paper presents a control strategy for performing complex work in an irregular environment, the control algorithm, the hydraulic circuit, and the master devices. The occurrence of collapse accidents at disaster sites such as natural disasters and building collapses is increasing, which is emerging as a social problem. In particular, for the initial response, various tasks must be performed in an irregular environment. The Marionette algorithm for intuitive control of 'as if the operator's arm is moving' was presented as a control strategy for dual-arm manipulators with attachments and the prototype. Next, the hydraulic circuit, control system, and wearable-type master device presented to implement the Marionette algorithm were explained and verified through an experiment in which rebar-cutting, drum-lifting, and lifting a bottle with one arm and pouring the water into the bucket with the other arm were tested.
https://doi.org/10.7839/ksfc.2020.17.4.031 인용 PDF KSCI

Iida, Michihisa;Umeda, Mikio;Namikawa, Kiyoshi
- Proceedings of the Korean Society for Agricultural Machinery Conference
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- 1993.10a
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- pp.820-829
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- 1993
We have developed an agricultural hydraulic robot to operate in the agricultural field. Using the robot, automatic harvesting experiments of watermelon were done. The results are as follows. First, the gripper should be modified its finger. Second, the manipulator and the gripper should be known precisely about dynamic characteristics of them in order to control adequately. Therefore, a new gripper was manufactured on trial by modifying its finger, and in order to known dynamic characteristics of the manipulator and the new gripper, the system identification was carried out with experiments.
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