GENERALIZED LINEAR SERVO-AERO-VISCOELASTICITY: THEORY AND APPLICATIONS 1

Servo-aero-viscoelastic theory is developed for linear viscoelastic lifting surfaces with many DOF. The utility of servo-controls is their ability based on closed loop feedback of current operating conditions to provide stabilization of creep divergence, control reversal, flutter and/or material failures of viscoelas- tic lifting surfaces, aerodynamic noise attenuation, delay column and panel creep buckling, increase panel flutter velocities, postpone delaminations and crack prop- agations in composites and produce prescribed morphing of UAV and MAV wing and tail surface shapes to produce desired flight effects. The effectiveness of pro- portional, differential and integral servo controllers is considered. The influences of the controller parameters on the flutter velocity are examined in detail. All these parameters, singly and in combinations, uniquely determine the wings viscoelastic response to inertia, lift, aerodynamic moments, and control forces and, therefore, no general conclusions can be drawn from any one example, since the system stability is strongly dependent on the phase relationships between the various contributing aerodynamic and control forces and moments, inertia, viscoelastic responses, etc.