Vibration Reduction Methods and Techniques for Rotorcraft Utilizing On-Blade Active Control

Rotor blades adapted for vibration control have the added benefit of extended blade and rotor life, as well as improved passenger comfort. Approaches that have been explored for on-blade active control or individual blade control include control surface actuation, such as trailing edge flaps, and integrated blade manipulation, such as controllable twist. For retro-fit and upgrade purposes, the advanced rotor system needs an actuation scheme with appropriate force, deflection, and bandwidth, without detrimentally increasing on-blade mass. Research in this area has been conducted with potential solutions employing various conventional active material actuator configurations, but these systems have typically suffered from inherent disadvantages. Due to these limitations, Techno-Sciences, Inc. proposes the use of pneumatic artificial muscles to actuate a trailing edge flap device for management of rotorcraft vibration. The proposed actuators are constructed of passive materials that are very mass efficient and low cost, while maintaining adequate force, stroke, and bandwidth. Oriented along the blade span and located within the airfoil contour near the blade root, the antagonistic configuration of actuators offers bi-directional flap deflection and operation under a low centrifugal field. A lightweight mechanism accompanies the actuators, running along the span, to transfer and tailor the mechanical work from the actuators to the span station of the flap. The proposed research plan will work to properly size and scale the actuators and mechanism for the desired response, and construct a prototype device that demonstrates the feasibility of the concept on the bench-top and in a rotating environment at full-scale loading.