Research On Constant-Pressure Hydraulic Power In Servo Valve Overlap Fluid Measuring Platform

During the performances of the SYT-I servo valve overlap hydraulic measuring platform, the pressure difference between the exit and the entrance keeps changing, which causes comparatively great principle error in the measurement and affects the accuracy of the measuring system. Due to this, it is important to improve the hydraulic power system and enable it to control the pressure change at the measuring points of the servo valve, thus to develop the SYT-II servo valve overlap hydraulic measuring platform and improve the processing quality of servo valve.This dissertation first analyzes the overlap measuring data of the SYT-I measuring platform and comes to the conclusion that the measuring error caused by pressure change is as high as 7.27%. Introduce the research and application of constant-pressure hydraulic power both in China and abroad and put forward and analyzes several constant-pressure hydraulic power controlling methods and pick out constant-pressure hydraulic power controlled by the proportional relief valve that fits the measuring system mostly. This constant-pressure hydraulic power adopts PLVC4 Programmable Logical Controller for Valve to control the electro-hydraulic proportional relief valve to adjust the pressure at the entrance of the servo valve and makes it change with the pressure change at the exit thus to keep the pressure difference constant. Based on this method,design the system oil circuit and constant-pressure hydraulic power station as well as the hydraulic manifold block, measuring platform, electrical cabinet and reclaiming oil tank.Regarding the hysteretic properties and time-varying of the system, the scan round performance of the controller, adopt incremental PID algorithm in constant-pressure controlling and combine it with the integral-separated dead-zone algorithm as appropriate for the situation of the measuring system and applies fuzzy self-tuning to control PID controller parameters. The fuzzy-PID controller with self-tuned parameters is finally designed out. The dissertation introduces the performance parameters of PLVC4 Programmable Logical Controller for Valve and its programming software OpenPCS. Connects it to the computer by serial communication and have the computer monitoring program...