Office of Technology Transfer – University of Michigan

Active Adaptive Noise and Vibration Suppression Based Upon Retrospective Controller Gradient Update

Technology #1472

Vibration and noise problematic in

Active noise and vibration suppression is an important aspect of creating modern heaters, air conditioners, and airplanes. However, all of the methods developed thus far suffer from one or more drawbacks such as inability to cope with sensor and broadband noise, need for direct disturbance measurement and model identification, and difficulty in establishing step size. The consequences of these shortcomings are instability and amplification of vibration and noise.

System for noise and vibration suppression without measurement of the actual disturbance

Researchers at the University of Michigan have developed a method and system for noise and vibration suppression that does not require measurement of the actual disturbance. This invention is applicable to a wide class of “disturbance rejection” problems, including active noise and vibration control. This invention provides a method and system that can utilize retrospective information obtained from sensors to account for the effect of the system and method over a window of time. The control parameters are revised in real time at discrete time steps to generate an input to the dynamical system that attenuates the effect of the exogenous disturbance on any chosen set of measured outputs of the dynamical system. The method for revising the controller parameters involves the steps of defining a novel retrospective cost function based on windows of past data, calculating a gradient that is based on this cost function, and using an implementable adaptive step size that brings the controller parameters closer to optimal controller parameters after each revision. The method and system are applicable to active noise and vibration control and reject single-tone, multi-tone, sine-sweeping and broadband disturbances in acoustic spaces.

Applications and Advantages


  • Heaters, air condition systems, and airplanes


  • Avoids expensive and complex sensing methods to detect the original noise characteristics


active noise and vibration suppression