Speaker ：Jonathan D. Ellis  

Time       ：August 26 ,2015  10：00  

Location：First meeting room of Research Building 

Abstarct ：Measurement standards exist based on machine tool and CMM calibration literature. Calibration using these methods typically employ quasi-static metrology. However, many systems are used in dynamic situations, where the characteristics of the stage can change between quasi-static and dynamic instances. Dynamic metrology impacts both the measurement target size and the signal processing electronics. In this work, we describe a method to measure piezo stages dynamically using Differential Wavefront Sensing (DWS). DWS enables simultaneous measurement of the displacement, pitch, and yaw of a target, while only requiring a small measurement target. We describe a method for compensating the dynamic phase effects in the signal processing electronics to reduce the error in non-constant velocity motion profiles. 

Speaker CV:Jonathan D. Ellis received his BS and MS in mechanical engineering from UNC Charlotte USA before heading to TU Delft in the Netherlands for his PhD. His PhD research was on optical metrology for dimensional stability measurements. He started at the University of Rochester in 2011 as an assistant professor with a joint appointment between the Department of Mechanical Engineering and The Institute of Optics. Dr. Ellis current runs the Precision Instrumentation Group, focused on advancing precision system design, metrology, and manufacturing. Dr. Ellis just completed a three year term on the Board of Directors for the American Society for Precision Engineering, where he has been a member since 2006. He is also a member of the Optical Society of America (OSA), SPIE, and the IEEE Instrumentation & Measurement Society and currently serves as Associate Editor for Precision Engineering.