A new approach to active control of rotorcraft vibrationA state-variable feedback approach is utilized for active control of rotorcraft vibration. Fuselage accelerations are passed through undamped second-order filters with resonant frequencies at N/rev. The resulting outputs contain predominantly the N/rev vibration components, phase shifted by 180 deg, and are used to drive the blade pitch to cancel this component of fuselage vibration. The linear-quadratic-gaussian (LQG) method is used to design a feedback control system utilizing these filtered accelerations. The design is based on a nine-degree-of-freedom linear model of the Rotor System Research Aircraft (RSRA) in hover and is evaluated on a nonlinear blade-element simulation of the RSRA for this flight condition. The system is shown to essentially eliminate vibrations at N/rev in all axes. The required blade-pitch amplitude is within the capability of conventional actuators at the N/rev frequency.
Document ID
19800061386
Acquisition Source
Legacy CDMS
Document Type
Conference Proceedings
Authors
Gupta, N. K. (Integrated Systems, Inc. Stanford, Calif., United States)
Du Val, R. W. (NASA Ames Research Center Moffett Field, Calif., United States)
Fuller, J. (Systems Control, Inc. Palo Alto, Calif., United States)