The objective of this award is to characterize the formation of interference fringes imposed on an object surface under an interferometer-equipped optical microscope and to derive an analytical three degree-of-freedom fringe image model for out-of-plane motion estimation and a warped shadow projection model for in-plane motion estimation. The proposed approach consists of three activities. First, a continuously shifting image model is proposed to achieve unbiased real-time image registration. Its application to pattern matching of warped images employed in six-axis visual sensing will be investigated to enable ultra-precise motion tracking. Second, a single software module that realizes six-axis visual sensing will be implemented to support multiple changeable vision sensors, including various objective lenses and cameras. Together with an interferometer-equipped optical microscope, they form a six-axis visual sensing system. Third, the visual sensing system will then be employed to achieve six-axis visual servo control that renders direct metrology for manipulation of multiple micro objects. Since the visual sensor's coordinate system coincides with the object space, the proposed visual servo control eliminates the effect of kinematic errors and continuously compensates for time varying uncertainties induced by interacting forces and/or thermal drifts.
If successful, technological innovations created from this award will open up important new research applications in manufacturing. The six-axis visual sensing system can serve as a feedback sensor to control the motion of various motion control stages, measurement probes, and manipulators for a wide spectrum of applications, including automatic alignment, tool-sample engagement, dynamic tracking, and controlled manipulation. It could be readily reconfigured to perform a breadth of functions for a variety of applications involving components that range in size from a few millimeters down to several micrometers. It represents a transformational change in how visual sensing and visual servo control can be used in ultra-precise metrology and manipulation.
