The bounds on tracking performance utilising a laser-based linear and angular sensing and measurement methodology for micro/nano manipulation

Abstract

This paper presents an analysis of the tracking performance of a planar three Degrees of Freedom (DOF) flexure-based mechanism for micro/nano manipulation, utilising a tracking methodology for the measurement of coupled linear and angular motions. The methodology permits trajectories over a workspace with large angular range through the reduction of geometric errors. However, when combining this methodology with feedback control systems, the accuracy of performed manipulations can only be stated within the bounds of the uncertainties in measurement. The dominant sources of error and uncertainty within each sensing subsystem are therefore identified, which leads to a formulation of the measurement uncertainty in the final system outputs, in addition to methods of reducing their magnitude. Specific attention is paid to the analysis of the vision-based subsystem utilised for the measurement of angular displacement. Furthermore, a feedback control scheme is employed to minimise tracking errors, and the coupling of certain measurement errors is shown to have a detrimental effect on the controller operation. The combination of controller tracking errors and measurement uncertainty provides the bounds on the final tracking performance.