A Novel Intelligent Adaptive Temperature ControlApproach of Sprayed Coating for APS Process

摘要

Coating damages, such as cracks and spallation, always occurrnunder high temperature gradient and its resulting residualrnstress level. This is why it is important and necessary tornmonitor and control the coating temperature duringrnatmospheric plasma spray process.rnIn this paper, a novel measurement approach for substrate andrncoating temperatures is presented. It is based on IRrnpyrometery combined to specific robot scanning trajectories inrnorder to avoid harsh environment of spray workshops. Therntemperature-time evolution was continually detected andrnrecorded during preheating, spraying and cooling stages andrnthe two specific factors, periodic average temperature andrnstandard deviation were adopted to evaluate the temperaturernvariation and the fluctuation of the thermal cycle relevant tornone robot scanning cycle based on the statistical method.rnThese two factors were successful in describing therntemperature variation during experimental processing sets.rnFinally, on the basis of experimental results of the influence ofrnZ typed robot spray trajectory parameters, including sprayrndistance, spray velocity and scanning step on coatingrntemperature characterized by the two factors, an intelligentrnadaptive control of sprayed coating temperature wasrndeveloped to obtain constant temperature cycles by means ofrnadjusting robot trajectories, cooling, among other consideredrnoperating parameters. Excellent control performance isrnobserved.