Adaptive Vibration Absorption Using Internal Model Control Approach

Anti-resonant vibration control is a technique that aims to mitigate unwanted vibrations when the system is excited with an exogenous disturbance. Vibration suppression is particularly interesting to avoid harmful effects, like inaccuracy in tool machines and robotics, discomfort in vehicles, and structural damages. Passive, semi-active, or active techniques are widespread in several practical applications. Active approaches have the advantage of being adaptive, i.e., the target frequency of the excitation to be absorbed can be modified. This aspect is fundamental in applications with time-varying disturbances. This paper proposes an internal model control strategy in the context of anti-resonant control for known and unknown frequency of disturbances. Based on some recent theoretical results in the literature, a receptance-based internal model control scheme is proposed to tackle exogenous disturbances that might cause severe vibrations. The approach is applied to control a meaningful example of underactauted multibody system: a two-link flexible-joint robotic arm controlled by just one motor. The numerical results illustrate the effectiveness of the approach.