Chordwise Implementation of Pneumatic Artificial Muscles to Actuate a Trailing Edge Flap

This work describes the theoretical design and experimental validation of a rotorcraft-specific trailing edge flap powered by pneumatic artificial muscle (PAM) actuators. The actuators in this work are co-located outboard on the rotor blade with the flap and arranged with a chordwise orientation where diameter and length restrictions can severely limit the operating range of the system. Techniques for addressing this configuration, such as introducing a bias contraction and mechanism optimization, are discussed and a numerical optimization is performed for an actuation system sized for implementation on a medium utility helicopter rotor. The optimized design achieves ±10 degrees of deflection at 1/rev, and maintains at least ±2 degrees half peak-to-peak deflection out to 10/rev, indicating that the system has the actuation authority and bandwidth necessary for both primary control and vibration/noise reduction.