液壓伺服閥系統人機介面之研發與測試

Abstract

本論文是使用電腦語言(Borland C++語言)撰寫液壓伺服閥控制的人機介面，利用運動控制卡 (凌華PCI-8136)透過序列串列埠(RS-232)傳輸方式對液壓伺服機台加以監測。 實驗中人機介面可設定波形的種類（步階、正弦波、方波和三角波）、波形的振幅與波形的頻率，經由控制器輸出電壓信號透過放大器轉換成電流來驅動伺服閥，其伺服閥開度與輸入電流是成比例。輸出的油流推動液壓缸，經由光學尺搭配解碼器可讓控制器讀取到目前液壓缸所在的位置，而力感測器可測量液壓缸碰到力感測器時回傳的信號，壓力感測器則可測得系統壓力的改變。再者，當液壓缸作動時，可透過攝影機同時監測液壓缸的狀況，防止在不正常的狀況下，操作人員反應不及而使得機台損壞造成危險。 本文之測試驗證了液壓缸摩擦力與油流壓力大小成反比，而與流量無關；而穩定時間的長短與壓力和電壓成反比。此外，數據顯示壓力增大時，系統損失的力量越大，但是當壓力超過23 以後，系統損失的力量會呈現非線性，其原因是受限於系統液壓缸的衝程。最後，透過此人機介面的開發，能讓進入液壓伺服領域的入門者，可以有更生動的學習方式，達到事半功倍的效果。

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.