Decentralized Vibration Control and Coupled Aeroservoelastic Simulation of Helicopter Rotor Blades with Adaptive Airfoils

Abstract

In the present paper, helicopter rotor blades with adaptive airfoils are investigated considering discrete trailing edge flaps as well as continuous shape adaptation. First, a method for lagging mode stability augmentation is proposed and applied to a helicopter rotor with discrete trailing edge flaps located at the outer part of the rotor blades. Active damping enhancement of the aerodynamically weakly damped lagging modes defines the control objective subject to the requirement of robust performance with respect to the time-periodic system behaviour. A decentralized controller is proposed which is shown to be robust, conceptually simple and effectively provides damping enhancement. In the second part, we discuss continuous shape adaptation in order to overcome the disadvantages of discrete flaps. An Active Camber Rotor (ACR) with distributed active material components is proposed. Numerical simulations are presented demonstrating the aerodynamic effectiveness of shape adaptation.

Development of a Span-Extending Blade Tip System for a Reconfigurable Helicopter Rotor

“…Recent advances in adaptive materials have led to a variety of schemes for on-blade actuation, such as adaptive twist of the rotor blade, 4,5,6 trailing edge flaps, 1,7,8,9 and active camber control. 10,11 Of these concepts, active twist of the rotor blade involves a large weight penalty due to the distributed nature of the actuators. Trailing edge flaps provide localized actuation and can generate significant control authority, but the discrete control surface and the discontinuities introduced in the airfoil surface have the potential to increase drag.…”

Development of a Quasi-Static Span-Extending Blade Tip for a Morphing Helicopter Rotor

“…Although these advanced blade shapes are quasi-static, feasibility of dynamic shape changing skin technologies has been proven for onedimensional structures [11][12][13], and airfoil structures [14][15][16][17]. Additionally, recent advances in adaptive materials have led to a variety of schemes for on-blade actuation, such as adaptive twist of the rotor blade [18][19][20][21][22], trailing edge flaps [23][24][25][26][27][28], active camber control [29][30][31][32][33], active rotor span [34], and chord morphing [35].…”

Wind Tunnel Testing of Pneumatic Artificial Muscles for Control Surface Actuation

“…Recent advances in adaptive materials have led to a variety of schemes for on-blade actuation in these areas (Chopra, 2000). Some of these include piezoelectric innovations such as adaptive twist of the rotor blade (Chen & Chopra, 1997;Chen et al, 2001;Shin et al, 2005), trailing-edge flaps (Straub et al, 2001;Fulton, 2000;Fulton, 2005), and active camber control (Konstanzer et al, 2001;Nissly et al, 2005). In comparing these approaches to active rotor systems, there are potential drawbacks, however.…”