Vibration Control of Piezoelectric Flexible Structure Using Robust Control Methodology

Active vibration control of a smart flexible cantilever beam was studied by using mode theory and μ synthesis method. The actuator is piezoceramic patch, the sensor is strain gauge. The finite element method and experimental modal test was applied to obtain the dynamic model of the smart structure. Taking account into uncertainty of the external disturbance and measurement noise, and uncertainty of natural frequency, damping ratio and actuator parameters of the system, μ synthesis approach was applied to design the vibration controller by selecting mode displacement as evaluation signal and selecting appropriate weighting function according to amplitude and frequency characteristics of the actual signal. A H∞ controller with same weightings was also designed and implemented for comparison analysis. The performances of the controller are verified experimentally in this study. Experimental results showed that μ -controller can provide good disturbance rejection and is more robust to parameter variations than H∞ controller. And the proposed controllers can effectively suppress the vibration response of the flexible beam.