This study presents an advanced output-feedback technique for speed regulation tasks in servo systems, which reduces the system model
independence and is independent of the current feedback, leading to fault tolerance. Hence, the output position error drives the model-free order
reduction filter for speed, and the acceleration feedback (as a replacement for the current loop) is admissible. Furthermore, the proposed control law
includes specially structured active damping terms in the feed-forward loop to actively trigger second-order pole-zero cancellation, forming a simple
single-loop proportional-integral derivative-type structure with compensation terms. Finally, a 420-W prototype DC servo system experimentally
validates the effectiveness of the proposed technique.