PERFORMANCE OF THE MINNESOTA SCANNER: A PROTOTYPE FOR 3-D TRACKING OF MOVING BODY SEGMENTS.

An advanced method of tracking the three-dimensional motion of bodies has been developed. This system has the potential of dynamically characterizing robot motion and facilitating their end-point control. Three rotating planes of laser light, fixed and moving photovoltaic diode targets, and a pipe-lined architecture of analog and digital electronics are used to locate multiple targets whose number is only limited by available computer memory. Data collection rates are a function of the laser scan rotation speed and are currently selectable up to 480 Hz. The tested performance on a preliminary prototype design for 0. 1 in accuracy (for tracking human motion) at a 480 Hz data rate includes a resolution of 0. 8 mm, a repeatability of plus or minus 0. 635 mm, and an absolute accuracy of plus or minus 2. O mm within an eight cubic meter volume with all results applicable at the 95% level of confidence along each coordinate direction. The system can be used to reduce XYZ target position data to body angular orientation for this first prototype ranges from plus or minus 0. 5 to plus or minus 1 degree . Moving targets can be tracked at speeds exceeding 1 m/s with signal integrity tested but not limited to 25 Hz motions.