Predictive control of 2D spatial thermal dose delivery in atmospheric pressure plasma jets

Atmospheric pressure plasma jets (APPJs) are unique devices for processing of heat and pressure sensitive (bio)materials. However, operational challenges of APPJs such as run-to-run variability in dynamics and sensitivity to disturbances can complicate safe and reliable delivery of the spatially distributed cumulative effects of plasma, or plasma dose, to complex surfaces. This paper presents a hierarchical feedback control strategy based on model predictive control for regulating the spatial thermal dose delivery to a surface. Closed-loop control experiments demonstrate the effectiveness of the proposed control strategy in drastically improving the spatial uniformity of thermal dose delivery in the presence of step changes in the jet tip-to-surface distance as well as abrupt changes in the substrate type. The proposed feedback control strategy shows promise for improving the reliability and effectiveness of spatially uniform treatment of complex surfaces in medical and materials processing applications of APPJs.