Adaptive control of structural intensity associated with bending waves in a beam

This paper examines a method to control adaptively the structural vibration intensity in a beam. An algorithm is developed to estimate the total, instantaneous structural intensity, using finite-difference techniques. In addition, algorithms based on the filtered-x least-mean-squares algorithm are developed to adaptively control the intensity. To investigate the effectiveness of adaptive control of structural intensity, a number of control actuator/error sensor configurations are used. Adaptive control is implemented at resonance and off-resonance frequencies, and the performance is evaluated by means of a separate accelerometer located in the structural far field. Experimental results demonstrate several trends. First, controlling the acceleration is considerably more effective when the error sensor is located in the far field rather than in the near field. Furthermore, controlling acceleration is more effective than controlling intensity, when the error sensors are in the far field. Conversely, when the error sensors are in the near field, the attenuation achieved by controlling intensity is comparable to or greater than that achieved by controlling acceleration.