Inverse signal shapers in effective feedback architecture

New feedback control architecture is proposed in this paper suitable for manipulation of weakly damped flexible structures. Delay-based signal shapers are considered since they are very popular in such applications for their simple implementation and very good performance. Unlike the classical approach where the shapers are used just to filter the reference command, we consider placing it inside the closed loop. Compared to previous attempts, we propose to include the inverse of the signal shaper's dynamics in the feedback path. This architecture is justified by thorough analysis of important feedback loop channels, namely the feedback response from input disturbance to the output. As results from the spectral properties, classical ZV shapers with lumped delays are very inconvenient for the shaper inverse operation, leading to neutrality of the dynamics with the associated risks of stability loss due to high frequency unstable modes. Therefore, a recently introduced DZV shaper with a distributed delay element is utilized in the feedback loop. Results are verified by simulations and experiments.