Development of an integrated electrical swashplateless primary and individual blade control system

Abstract

It has been shown that a helicopter rotor in forward flight can greatly benefit from more complex pitch control schemes than used today. Thus, control system add-ons have been realized which provide those missing degrees of freedom, usually referred to as Individual Blade Control (IBC). If such systems are added to a conventional control system, however, additional means of actuation have to be placed in the rotating frame, which require their own information and power transfer links. Instead of implementing additional separate hardware it might be worthwhile to consider an integrated actuation system designed to fulfill both the primary control as well as the IBC requirements. This paper discusses the following three aspects: (a) what are the performance requirements of such an integrated control system which is able to fulfill both functions, (b) what actuation technology is best suited for this application and (c) how can the reliability required for a primary flight control system be realized with a minimum degree of redundancy and thus at a competitive system weight? It is shown that by using modern customized electromechanic actuators and by choosing an appropriate system architecture this type of integrated control system becomes feasible at a very competitive system weight. This paper presents the basic principles, discusses the multi-disciplinary investigations and describes the approach to demonstrate its feasibility through dedicated bench tests.