Control of a microscale deposition robot using a new adaptive time-frequency filtered iterative learning control

Douglas A. Bristow, Andrew G. Alleyne, Danian Zheng

Research output: Contribution to journalConference articlepeer-review


A Robocasting manufacturing process and robotic deposition machine are presented. The process requires that the machine be able to track 3-D trajectories with high precision. Iterative Learning Control (ILC) is presented as a viable strategy to meet these demands. Typically, practical implementation of ILC requires some type of Q-filtering that creates an inherent tradeoff between performance and robustness. This tradeoff can be minimized by using a time-varying Q-filter that has been tailored to the system and reference trajectory. A new adaptive time-frequency Q-filtered ILC algorithm is presented to adaptively construct a tailored time-varying Q-filter. Further, because the approach is adaptive, the performance is not limited by overly conservative uncertainty models. A simulation example is presented to demonstrate that, when designed for a nominal plant, the adaptive Q-filtered ILC has performance comparable to that of a standard, fixed-bandwidth Q-filtered ILC. When a perturbation of the plant is introduced, the adaptive Q-filtered ILC adapts to maintain stability, whereas the fixed-bandwidth Q-filtered ILC becomes unstable. The adaptive algorithm is applied to the robotic deposition machine to demonstrate the ability of the algorithm to achieve high precision in this application.

Original languageEnglish (US)
Pages (from-to)5144-5149
Number of pages6
JournalProceedings of the American Control Conference
StatePublished - Nov 29 2004
EventProceedings of the 2004 American Control Conference (AAC) - Boston, MA, United States
Duration: Jun 30 2004Jul 2 2004

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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