Wind Tunnel Testing of an Individual Blade Controller for a Dissimilar Rotor

摘要

An adaptive control algorithm is developed to reduce hub vibration of a dissimilar rotor. The control strategy is implemented using smart material actuated on-blade trailing edge flaps. Each flap is controlled individually, optimally taking into account blade dissimilarities. A flexure based piezobimorph actuated trailing edge flap system is incorporated for a Mach scaled rotor for implementation of the controller in wind tunnel. Vacuum chamber and hover tests are carried out first, followed by tests in the Glenn L. Martin wind tunnel. Flap deflections of +-4° are obtained at 1800 rpm with tip Mach number 0.45 in hover test. Closed loop tests are conducted in hover and forward flight to minimize the vibratory blade root flap bending moment. Effective reduction of I/rev vibration in hover is demonstrated. Because different inputs are used for each blade, it is possible to minimize the rotating frame vibration for several blades simultaneously. In forward flight, only single harmonics could be targeted efficiently because of limited actuation authority. At 1500 rpm and advance ratio 0.12, the 3, 4 and 5/rev harmonics of root flap bending moment are reduced by 40%, 91%, and 91% respectively when targeted alone, with trailing edge flap deflections smaller than 2.8°.