Precise regulation of powder mass flow in laser-based manufacturing processes is critical to achieving excellent part dimensional and microstructure quality. Control of powder mass flow is challenging because low flow rates, where nonlinear effects are significant, are typically required. Also, gravity-fed powder feeder systems have significant material transport delays, making the control of powder mass flow even more challenging. This paper presents a control strategy for regulating the powder mass flow rate in a gravity-fed powder feeder system. A dynamic model of the powder feeder system, including material transport delay, is constructed, and a modified proportional plus integral (PI) controller is designed. An observer is used to estimate powder mass flow rate using the powder feeder motor encoder signal. The control strategy is implemented in a Smith Predictor Corrector Structure, which has been adjusted such that it can be applied to the modified PI controller, to account for the inherent material transport delay. Experimental studies are conducted that validate the dynamic model and controller strategy.
V. Thayalan and R. G. Landers, "Regulation of Powder Mass Flow Rate in Gravity-Fed Powder Feeder Systems," Journal of Manufacturing Processes, Elsevier, Jan 2006.
The definitive version is available at http://dx.doi.org/10.1016/S1526-6125(06)80007-1
Mechanical and Aerospace Engineering
National Science Foundation (U.S.)
Society of Manufacturing Engineers. Education Foundation
University of Missouri--Rolla. Intelligent Systems Center
University of Missouri Research Board
Keywords and Phrases
delay control; gravity-fed powder feeders; laser-aided manufacturing; powder mass flow regulation
Article - Journal
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