MEMSEye for optical 3D position and orientation measurement

Abstract

This work aims to advance 3D position input and motion sensing in a variety of human-machine interface (HMI) and industrial robotics systems with a MEMS-mirror based optical 3D tracking approach which we termed "MEMSEye." The goal is to enable real time interaction with computers and robotics in ways that are more intuitive, precise and natural. Objects can be tracked which are marked either by light sources (e.g. a near-IR LED,) corner-cube retroreflectors (CCRs,) or with retro-reflective tape. Each "MEMSEye" unit can track the object with high speed and determine with high precision the azimuth and elevation (θX and θY) angles of the line between the unit and the object. When two or more such units are utilized to triangulate the object, relative position can be fully determined since distance information can also be obtained. This final XYZ position information down to sub-millimeter precision can be obtained in relatively large volumes at update rates of >20 kHz. A demonstration system capable of tracking full-speed human hand motion provides position information at up to 4m distance with 13-bit precision and repeatability. In another demonstration, a vector in free space is marked by two target CCRs and the MEMSEye system measures its orientation in space with ~0.1° precision by locating both CCRs in a time-multiplexed manner.