Candidate: Irving Muraro
Program: UFSC / POSMEC
Date: December, 2009
Advisor: Victor Juliano De Negri
Abstract: The difficulty of projecting electro-hydraulic control systems is due mainly to the variations and uncertainties of static and dynamic characteristics of the system’s components, being of great importance and influence in the positioner performance the continuous directional flow control valve. In this context, the present work presents a theoretical-experimental analysis of the proportional valves behaviour and of its effects in electro-hydraulic positioners. Using as reference the preliminary project systematization of hydraulic position control systems elaborated by Furst and De Negri (2002), it was noticed the necessity of accomplishing a detailed study of valves main characteristics, such as natural frequency, damping ratio, flow coefficient and pressure gain. Considering the application of electro-hydraulic system in the positioning and driving of heavy loads in specific time period, characteristics that changes according the operation conditions, such as the cylinder and system natural frequencies are also analysed. The variation and influence of these parameters in the closed loop hydraulic control systems behaviour using a proportional controller are evaluated via mathematical models implemented using Matlab/Simulink software. The models validation and the practical verification of the simulation results are accomplished with the use of “Proportional Hydraulic Platform” workbench. The knowledge in this study clarifies and solves some of design and dynamic performance problems of an uncorrected projected system. Therefore, this work provides the improvement of design methodologies in electro-hydraulic control systems project.
MURARO, I.. Estudo das Características Comportamentais de Válvulas Proporcionais e seus Efeitos nos Posicionadores Eletro-Hidráulicos. 2009. Dissertação (Programa de Pós Graduação em Engenharia Mecânica), 176 p. Universidade Federal de Santa Catarina.