Fundamental Study of Active Vibration Control in Rotorcraft Using the ACSR Approach

摘要

This is the final report describing the objectives and accomplishments of the research conducted under the above referenced grant. The general purpose of this grant has been to study a novel approach to active vibration control in helicopter fuselages known as the Active Control of Structural Response (ACSR) approach. In this approach vibrations in the helicopter fuselage are reduced by introducing harmonically varying forces by actuators located between the rotor and the fuselage such that the sum of the response of the airframe, due to rotor loads and external excitation, is reduced to a minimum. The primary objectives of this research were: (1) development of a coupled rotor/flexible fuselage model capable of simulating the vibrations in the fuselage and their control using the ACSR system, (2) modeling of the closed loop vibration reduction using two different control algorithms, a simple algorithm denoted the BACSR-algorithm, and a more refined algorithm based upon the internal model principle, denoted as the IMP-algorithm, and (3) conduct trend studies, to demonstrate vibration reduction throughout the flight envelope of the helicopter. All the objectives stated were achieved in the course of the research. Reduction of vibration levels below 0.04g was demonstrated throughout the ffight envelope, with relatively modest control effort, and low control power requirements. This research also provided a fundamental understanding of the approach that was not available from the experimental and empirical studies conducted before.