Development of an Experimental Blade-controlled Cycloidal Propeller

Abstract

As an interesting naval propulsion system, this paper presents the development of an experimental cycloidal propeller. Cross-flow propellers are characterized by the rotation of several blades around a vertical axis associated with a movement of each blade around its axis (blade pitching). Two kinematic modes depending on the advance coefficient Lambda are distinguished: cycloidal mode for low ship speeds (Lambda < 1) and trochoidal mode for high speeds (Lambda > 1). The final goal is to establish pitch laws, for each of those two modes, dealing with a target optimization (thrust maximizing for example). For this purpose, an experimental thruster designed at the IRENav can perform more or less complicated pitch laws thanks to three servo motor controlling each blade independently. Kinematics of cycloid propellers is first outlined, and pitch laws are defined by a quasi-static approach. Then Ifremer facilities of Boulogne-sur-Mer are presented. The experimental thruster is also described as its current blade-control system. Finally, improvements on the electronic command have proceeded through the development of a Digital Twins and a test bench.