Seok-Kyoon Kim and Kyo-Beum Lee, "Active Second-Order Pole-Zero Cancellation Control for Speed Servo Systems with Current Sensor Fault Tolerance," IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 70, no. 6, pp. 2196-2200, Jun. 2023. -SCI > Paper

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.