SLIDING MODE BASED ACTIVE VIBRATION CONTROL OF A FLEXIBLE BEAM USING PIEZOCERAMIC MATERIALS

摘要

This paper presents the design and testing of a sliding mode based active vibration controller for a cantilevered flexible beam with piezoceramic sensor and actuators. The piezoceramic sensor and actuators are in patch forms and are surface-bonded to the cantilevered end of the flexible beam. With advantages of being robust to plant parameter variation, insensitive to the unmodeled dynamics, and easy to implement, the sliding mode control is adopted in this paper for active vibration control of the flexible beam. Unlike other commonly used vibration suppression methods such as, positive position feedback control, strain rate feedback control, and lead compensation, the sliding mode controller requires almost no knowledge of the flexible beam. To avoid the chattering problem commonly associated with the sliding mode control, a smooth switching function employing a hyperbolic tangent function is used. Also a low pass filter is applied to the output of the sliding mode controller to avoid excitation of the higher modes of the flexible beam. To demonstrate the advantage of the sliding mode based active vibration reduction, its experimental results are compared with those of Proportional plus Derivative (PD) control and lead compensation. The comparison shows that the sliding mode controller reduces vibration of the flexible beam in a much quicker fashion.