Aeromechanical Stability Augmentation Through Semi-Active Control

Helicopter rotors have traditionally been equipped
with passive dampers for aeromechanical stability.
These passive systems have fixed characteristics, and
add to mechanical complexity and high maintenance
cost. Furthermore, they are unable to change to
compensate for an unexpected loading trends as
typically encountered by a rotary wing vehicle.
Semi-active control strategies are dissipative in
nature, inherently stable, and require a little
energy to operate. Hence, they appear to be
particularly promising in addressing a
number of the challenges facing active control
strategies, in that the devices are low power,
fail-safe, and reliable. In this study, author
investigates friction based semi-active approach for
ground resonance stability augmentation and proposes
novel strategies for the adaptive, selective and
individual damping control. The effectiveness of
these control strategies is validated on a
comprehensive multibody system model of an army
helicopter. The analytical study is supplemented with
a novel design of a semi-active lead lag damper and
various aspects of its design in application to
commercial rotors are discussed.

Autorentext

Dr. Sandeep Agarwal is a Rotor Dynamics Engineer at the Boeing
Company. Prior to that, he worked at the Center of
Excellence in Rotorcraft Technology at Georgia Institute of
Technology. His primary interests include Rotor dynamics,
Aeroelasticity, Structural Morphing and Structural
Optimization. He has authored several technical publications.

Klappentext

Helicopter rotors have traditionally been equipped
with passive dampers for aeromechanical stability.
These passive systems have fixed characteristics, and
add to mechanical complexity and high maintenance
cost. Furthermore, they are unable to change to
compensate for an unexpected loading trends as
typically encountered by a rotary wing vehicle.
Semi-active control strategies are dissipative in
nature, inherently stable, and require a little
energy to operate. Hence, they appear to be
particularly promising in addressing a
number of the challenges facing active control
strategies, in that the devices are low power,
fail-safe, and reliable. In this study, author
investigates friction based semi-active approach for
ground resonance stability augmentation and proposes
novel strategies for the adaptive, selective and
individual damping control. The effectiveness of
these control strategies is validated on a
comprehensive multibody system model of an army
helicopter. The analytical study is supplemented with
a novel design of a semi-active lead lag damper and
various aspects of its design in application to
commercial rotors are discussed.