Daniel H. Miller
William T. Baumann
Dept. of Elec. Eng., Virginia Polytechnic Inst. and State Univ., Blacksburg, VA 24061
The paper presents experimental results of a hybrid control technique that blends traditional fixed feedback control with adaptive feedback techniques. The objective is to provide damping for transient disturbances via the fixed part of the controller and rejection of steady disturbances via the adaptive part of the controller. This technique differs from the other hybrid techniques in that it does not require a measurement of an external signal coherent with the disturbance, nor does it require knowledge of how the disturbance enters the system. In addition, it provides damping to the system, unlike neutralization-loop techniques. As with all feedback techniques, stability is an issue. The adaptive controller is implemented in such a way as to minimize stability problems and in the case of perfect system identification it is guaranteed to be stable. The experimental results are from a cantilever beam with piezoceramic actuators and sensors. The results for the fixed feedback controller will be compared to those for the adaptive feedback control technique. The comparison will include results from harmonic, narrow-band, and broadband disturbances. [Work supported in part by ONR contract N00014-92-J-1170.]