Research on the Rotor of a Ducted Fan Propulsion System of MOSUPS Aircraft Taking into Account Self-Balance during Operation

The work concerns the research of a propulsion system for an unmanned aerial vehicle MOSUPS in joined wing configuration. Modeling, analysis and experimental research of a statically unbalanced rotor of a ducted fan propulsion system has been conducted.The aim of the analysis was to determine the critical rotational speeds of the rotor due to the probable excitation of oscillations. Due to the complex geometry, Finite Element Method has been used for the calculations. In the study, the critical frequencies (and also rotational speeds) of the rotor as well as precessional instability, flexibly mounted in the bearings have been calculated. Campbell and SAFE diagrams have been presented.Furthermore, the paper presents the idea for a device for automatic dynamic balancing of the mentioned rotor. A mechanism for changing the position of the correction weights has been developed, allowing for a long term operation of rotating parts without the need to stop the unit and correcting the unbalance.The main motivation for work was to fully understand the working conditions of the propulsion system and dynamic properties of the rotor in order to carry out a proper assessment of their impact on the safe operation of the aircraft.

Adaptive Virtual Autobalancing for a Magnetic Rotor With Unknown Mass Imbalance: Part II — Dynamic Balancing

In Lum et al. (1995), an adaptive control algorithm for the stabilization of a rigid, statically unbalanced rotor moving in the plane was proposed. The control strategy consisted in emulating a mechanical autobalancer using magnetic actuation so as to directly cancel the effects of static mass imbalance. In this present paper, this strategy is extended to the case of a rigid, dynamically unbalanced rotor in six degree-of-freedom motion. The state equations of the controller are based on the equations of motion of a multiple-plane autobalancer, and the control forces partially emulates the interaction between rotor and autobalancer. It is shown in simulation that the adaptive virtual autobalancing control can achieve stabilization of rotor motion as well as adaptation to changes in imbalance.