Active control of a flexible smart beam using a system identification technique based on ARMAX

A study on active vibration suppression for a flexible structural beam via a system identification approach was experimentally performed. The beam, incorporating a pair of piezoceramic transducers as actuators and a set of surface-bonded strain gauges as sensors, was evaluated. The relationship between the input control voltage applied on the actuators and the consequently induced strain, measured by the sensor, was then derived. An active control system, considering both the actuators and sensor, was configured using the ARMAX (auto-regressive moving average exogenous) model. A continuous signal with step waveform was selected as the input excitation. A digital-signal-processor-based real-time adaptive vibration control algorithm, supported by Agilent^® E1415A, SCPs 1511 and SCPs 1532, was developed, and an algorithm was established using a pole placement control method, so as to achieve the desired closed-loop control. The effectiveness of the ARMAX model was examined by comparing it with the ARX (auto-regression with extra inputs) model. The results show good performance of the ARMAX model for system identification purposes and excellent effectiveness for active structural vibration control.