Development and testing of a human-machine interface for servo-valve hydraulic systems
Date Issued
2007
Date
2007
Author(s)
Li, Chin-Kai
DOI
zh-TW
Abstract
The main purpose of this study is to develop a human-machine interface monitoring for hydraulic servo-valve systems by programming with a Borland C++ language. A series transmission mode RS-232 with a motion control card (PCI-8136, Advantech) is used to drive this hydraulic servo system.
In the experiments, wave types (step, sine wave, square wave and triangle wave), wave amplitudes and wave frequencies can be set. The electric current from a controller will actuate the hydraulic servo valve. The opening of a servo valve is proportional to the current. The hydraulic flow will then force a hydraulic cylinder to move. A linear scale is used to detect the positions of the hydraulic cylinder. A load cell is used to detect the forces after the cylinder rod touches the load cell. A pressure transducer is used to detect the hydraulic pressure continuously. When the hydraulic cylinder moves, a camera can monitor its motion simultaneously and check whether the condition is normal.
The tests show that the friction force of a hydraulic cylinder is inverse proportional to the hydraulic pressure; the stable time is inverse proportional to the hydraulic pressure and (electric) voltage. If the pressure increases, the losses of the system’s force will also increase, but when the pressure is larger than 23 , the loss becomes non-linear. This is due to the limitation of the stroke of the hydraulic cylinder. Therefore, the system’s max. effective pressure is 23 . Finally, by the development of this human-machine interface, we hope the beginners of the hydraulic servo system can use an interesting way to learn and they can reach their goals as soon as possible.
Subjects
液壓伺服閥
人機介面
序列串列埠傳輸
hydraulic servo valve
human-machine interface (HMI)
RS-232 transmission
Type
thesis