Video for Enhancing Nanopositioning Bandwidth via PAVPF and Pole Placement in the Presence of Delay

This paper presents a delay-compensated control approach for nanopositioning systems based on the Positive Acceleration, Velocity, and Position Feedback (PAVPF) control scheme to mitigate the detrimental effects of time delay on frequency response and tracking accuracy. By incorporating delay into the system model using Padé approximations, the proposed method ensures a well-determined system, simplifying calculations and facilitating controller design. Experimental results demonstrate that delay compensation significantly improves system bandwidth and tracking performance, particularly at higher frequencies. Compared to an uncompensated design, the proposed controllers exhibit increased bandwidth and reduced root-mean-square (RMS) and peak errors during tracking tests. However, the maximum performance is constrained by higher harmonics when simultaneously designing for damping and tracking. A correlation between pole positions and optimal stability can be established by correctly identifying these limiting harmonics, leading to the best possible outcome while maintaining robustness. Additionally, the PAVPF control scheme outperforms the previous Positive Velocity and Position Feedback (PVPF) approach, further enhancing system performance.