Active Damping Control of Higher-Order Resonance Mode in Positioning Systems

There is an ever-increasing demand for faster and more accurate motion stages in the high-tech industry. In precision positioning systems, lightly damped higher-order resonance modes can induce undesirable vibrations that degrade system performance and accuracy. These resonances pose additional challenges in non-collocated dual-stage positioning systems, where they significantly limit control bandwidth. Although conventional notch filters are commonly used alongside tracking controllers to enhance bandwidth, they lack robustness when faced with system parameter uncertainties. Moreover, the effects of the parasitic resonance on disturbance rejection remain. Active damping control has been successfully used to mitigate issues related to the primary resonance mode, but its application to higher-order parasitic modes has not been explored. This research introduces a novel control strategy, High-Pass Positive Position Feedback (HP-PPF), designed specifically for the active damping of higher-order, non-collocated parasitic modes in positioning systems. The proposed method incorporates a second-order high-pass filter within a positive feedback loop, effectively attenuating the parasitic resonance. Integrated with a PID tracking controller in a dual-loop configuration, this method enhances disturbance rejection, noise suppression, and robustness against model uncertainties, overcoming limitations of traditional notch filter-based methods while maintaining comparable tracking performance. The proposed control architecture is validated through a proof-of-concept experimental setup that demonstrates the effectiveness of the underlying mathematical framework.