A Thrust Vector Control Jet Nozzle for Submersible Vehicles

In order to collect a lot of useful information under severe environmental conditions in the ocean, the development of remote controlled submersible vehicles which have excellent performance is considered important. The vehicles need a thruster for attitude control that has a high degree of freedom for thrust vector and a high response speed.This paper presents a new jet thruster for submersible vehicles. The thruster is a three-dimensional fluidic thrust vector control (TVC) nozzle, of which the main jet deflects to any direction by selectively regulating four control jet thrusts and produces radial thrust for vehicle maneuvering.To evaluate its performance, the following procedure was undertaken. First, the behavior of the jets was experimentally examined using flow visualization and image processing techniques to study the effects of nozzle design parameters. Next, both static and dynamic characteristics of the radial thrust were experimentally investigated. Finally, the step response of real radial thrust was inferred from the simulation of the TVC nozzle and measurement systems.As a result, the following facts were specifically confirmed:1) The jet behavior is affected especially by both offset and vent of the TVC nozzle.2) A main jet deflects effectively and a large radial thrust can be obtained by a small control jet thrust.3) The dead time of the TVC nozzle is much less than one second. Therefore, the response characteristic is superior to that of conventional moving part type thrusters.