Development of Water Hydraulic Servo Control System Considering Water Characteristics.

Abstract

The oil hydraulic servo control system has a long history of application to various machines. However, a cleaner hydraulic fluid is necessary as we are faced with problems of fire or contamination due to oil leakage. We succeeded in improving the performance of a water hydraulic servo control syrstem over that of the oil hydraulic servo control system. Our water hydraulic servo control system is based on the analysis of the advantages of the physical properties of water for servo control. Furthermore, we can fabricate a simple water servo control system consisting of least components which can cover a wide dynamic performance range and can guarantee the same applications fields as the oil hydraulic servo control systems. Important components are the wide-dynamic-range water hydraulic pump system and the high-response, wide-dynamic-range water servo valve. The performance and durability of the system and components were tested and verified. As a result, the water hydraulic servo control systems are found to be the same as or superior to the oil hydraulic servo control system. Applying the advantages of the properties of water to a design, we can achieve better performance and lower cost with the water hydraulic servo control system than the conventional oil hydraulic servro control systems.