Unknown disturbance estimation for vibration systems using distributed piezoelectric sensors

Vibration is usually caused by external disturbances, which may lead to structural damage. Vibrations can be significantly suppressed by taking disturbances into account. However, in many cases disturbances are unknown or difficult to be measured directly. In order to estimate external unknown disturbances, this article develops a proportional-integral (PI) disturbance observer with measurement noises for smart structures using multiple distributed piezoelectric sensors. For simulation purpose, a dynamic finite element model of piezoelectric bonded smart structure is presented. This disturbance observation method is validated by estimating various kinds of unknown disturbances using piezoelectric measurements. Furthermore, the measurement numbers and the position of measurements are investigated.