Adaptive Feedforward Cancellation Scheme Temporarily Using Negative Damping to Speed Up the Transient Response When Counteracting Periodic Disturbances

Adaptive Feedforward Cancellation (AFC) is commonly used to counteract periodic disturbances in mechatronic systems in order to enhance the control performance. So far, AFC algorithms either use no or positive damping. In this research, we investigate the behavior of AFC algorithms deliberately using negative damping in both simulation and experiment. While their frequency responses are mostly comparable, we find that the deliberate introduction of negative damping can significantly speed up the initial transient response of the AFC but then overcompensates, resulting in a steady-state error. Motivated by this, we then propose and experimentally test a new AFC algorithm that initially uses negative damping to secure a fast transient response and then switches off the damping in order prevent the overcompensation and secure a zero steady-state error.