Hydraulic Pressure Fed System Using Helium Gas and Fast Electro-Hydraulic Actuator Applied to Brazilian Sounding Rockets and Microsatellite Launchers

This work presents the research and technological development of a hydraulic high Pressure Fed System (named PFS) using Nitrogen/Helium gas and a fast electro-hydraulic actuator (FEHA) applied to movable nozzles for Brazilian sounding rockets and microsatellite launchers. The preliminary control capability analysis to sounding rockets design requires a high performance FEHA, e. g. the bandwidth, to perform the attitude control using the Thrust Vector Control (TVC) strategy. The Thrust Vector Assembly (TVA) consist of the PFS mounted on the EHA that controls the nozzle angular movement, in closed-loop operation. Modeling and simulation results using AMEsim environment show the PFS performance compared to step-unit response obtained from experimental tests. Frequency Response Functions (FRF) are obtained from experimental data using sinusoidal signals of excitation with frequency from 1 to 10 Hz, and the bandwidth Bw is accessed. Equipment to the PFS includes a pressure regulator to the helium gas in order to pressurize the hydraulic fluid with a constant pressure of 200 bar. A high performance electro-valve controls the oil flow in the hydraulic cylinder and a real-time digital controller is implemented to stabilize the closed loop. The results are of very interest if compared to the European actuator flight model of the Brazilian satellite launcher vehicle VLS-1. Details and improvements are discussed in order to obtain best bandwidth in the next FEHA engineering model, e.g. the digital flow control technique to the servo-valve.