The Hummingbird minipositioner-providing three-axis motion at 50 g's with low reactions

The Hummingbird minipositioner is a three-axis servo-mechanism designed to provide fast and accurate positioning of a low-mass probe tip on or above a nearly planar object. Peak XYZ accelerations in excess of 500 m/s/sup 2/ (50 g) are obtained, with positioning resolution under 1 mu m and a workspace of 13 by 13 by 1 mm. The system weighs 950 g and is nearly reactionless during X-Y motion to simplify integration with large-area positioners. The design of the dynamically balanced five-bar linkage assembly and the Z-actuator is presented, along with data on in-plane linkage resonances (shown to be >1 kHz) and the torque cancellation effectiveness. A typical incremental move of 5 mm with 50 g peak acceleration and a move time of 8 ms is also presented.<<ETX>>