Best Paper, ISCIE/ASME International Symposium on Flexible Automation

Dan Wang and I received the Best Paper Award on July 19, 2018, at the Japan Institute of Systems, Control, and Information Engineers (ISCIE) / ASME International Symposium on Flexible Automation. Our paper, titled “Synthesis and analysis of multirate repetitive control for fractional-order periodic disturbance rejection in powder bed fusion,” represents a significant step forward in advancing additive manufacturing control techniques.

In this work, we focused on improving the repetitive energy deposition process in Powder Bed Fusion (PBF), a cutting-edge additive manufacturing technology. The repetitive scanning of laser or electron beams in PBF inherently benefits from Repetitive Control (RC) algorithms. However, practical challenges arise when the periodicity of the disturbance does not align with the system’s sampling rate, resulting in fractional-order cases that limit control performance.

To address these challenges, we proposed a novel multirate repetitive control (RC) method and developed a comprehensive analysis framework for closed-loop behavior in fractional-order scenarios. Our approach enables high-gain control at both fundamental and harmonic frequencies, overcoming intrinsic limitations of traditional discrete-time RC. Numerical simulations and validations on a galvo scanner in a laser PBF system demonstrated the substantial benefits of the proposed method in enhancing precision and quality in energy deposition.

My deepest thanks to the ISCIE/ASME symposium committee for this honor and congratulations to all the participants contributing to the advancement of flexible automation.