Abstract: A plurality of capaciflector proximity sensors, one or more of which may be overlaid on each other, and at least one shield are mounted on a device guided by a robot so as to "see" a designated surface, hole or raised portion of an object, for example, in three dimensions. Individual current-measuring voltage follower circuits interface the sensors and shield to a common AC signal source. As the device approaches the object, the sensors respond by a change in the currents therethrough. The currents are detected by the respective current-measuring voltage follower circuits with the outputs thereof being fed to a robot controller. The device is caused to move under robot control in a predetermined pattern over the object while directly referencing each other without any offsets, whereupon by a process of minimization of the sensed currents, the device is dithered or "wiggled" into position for a soft touchdown or contact without any prior contact with the object.
Type:
Grant
Filed:
November 28, 1994
Date of Patent:
July 23, 1996
Assignee:
The United States of America as represented by the Administrator of the National Aeronautics and Space Administration