Parameter Estimation and Line Width Control of Robot Guided Inkjet Deposition

Abstract

In the field of inkjet deposition, there is a lack of specific knowledge to detect and change drop volume to regulate fluid placement. In this paper, we present a novel control scheme to regulate drop diameter on a surface with unknown properties. We derive a model for line width as a function of nozzle velocity, valve duty cycle, and physical properties of fluid and surface. As many of these variables are generally unknown, we present a nonlinear estimator to estimate their cumulative effects as a single variable. Next, benefiting from our estimation knowledge, a closed-loop control method is designed to track a time-varying line width. Stability of both the estimator and control are established using Lyapunov stability theory, and the control is shown to be robust to errors in the estimator. Simulations and experimental results confirm the stability and performance of the approach.