Feedback control for canceling mechanical vibrations

Linear quadratic Gaussian (LQG) control is applied to the application of active vibration cancellation. The virtual mass of a vibration motor is controlled based on measurements of acceleration. The final controller is a modified LQG design developed for an augmented model of the vibration motor. This paper describes the modeling and parameter identification of the vibration motor, development of performance specifications for the controller, design of the LQG controller, and experimental testing of the resulting control system. Modeling of the vibration motor was based on both theoretical derivation and experimental data collection. Development of the specifications for the controller was drone primarily in the frequency domain, using the return ratios of two different transfer functions. Controller design was done using the continuous-time LQG algorithm. The controller was implemented as an analog circuit with operational amplifiers. Some closed-loop stability issues were observed during the experimental testing, and an explanation is offered for these problems.