Design of modulated and demodulated controllers for flexible structures

We propose a novel method for controlling vibrations within a resonant structure equipped with piezoelectric transducers. The scheme uses a parallel connection of modulated and demodulated controllers, each designed to damp the transient oscillation corresponding to a single mode. This technique allows multiple modes to be controlled with a single actuator. A simulation example is presented and design considerations for the scheme are discussed. Experimental results obtained from a piezoelectric laminate cantilever beam confirm the theoretical analysis.