Welcome to the Bucknell University/University of Washington website for the study of Pulse-Width Control. This site is the result of on-going research supported by National Science Foundation grant number CMS-0409055. Documented here is work done by students at Bucknell as well as students at the University of Washington.

Work to date has focused on extending the basic pulse-width control theory developed by Yang and Tomizuka in 1988 and builds directly on results developed by Rathbun, Berg, and Buffinton for the application of pulse-width control to structurally flexible dynamic systems. Also documented here are studies of pulse-width control done both at Bucknell and the University of Washington prior to the start of grant support. The physical systems used in these studies, as well as for on-going research, are shown below.

Industrial Robot at Boeing
Industrial Robot at Boeing
Test Apparatus at University of Washington
Test Apparatus at University of Washington
Bucknell Test Apparatus
Test Apparatus at Bucknell
Bucknell Students
Bucknell Group Picture

As described in more detail in the Project Summary portion of this site, the primary goal of the current research is significantly improving the accuracy of robotic devices that are subject to the deleterious effects of Coulomb friction, stiction, and link and joint flexibility. This has already been achieved for single degree-of-freedom systems and results are promising for those with multiple degrees of freedom. A unique aspect of this research for multi-degree-of-freedom systems is the use of tables of pulse-width gain values rather than simply a single gain for each axis of motion. In both simulation and experiments, tabular pulse-width control has been shown to produce responses that converge rapidly and achieve positioning accuracies equal to the precision of the measurement sensors.