Ultrasonic apparatus for positioning a robot hand

Apparatus for precisely positioning a movable robot arm with respect to a surface of a workpiece, response to a first orientation command signal, a second orientation command signal, and one distance command signal, comprising:

• an acoustic transmitter mounted on the robot arm, said transmitter emitting a periodic acoustic signal against the surface of the workpiece;
• a first acoustic receiver, a second acoustic receiver, and a third acoustic receiver arranged noncolinearly on the robot arm, and positioned to receive return signals from the surface of the workpiece resulting from impingement of the emitted acoustic signal upon the surface;
• a first comparator that calculates a first measured comparison signal proportional to the difference in the time of flight of an acoustic return signal from said transmitter to said first receiver and the time of flight of an acoustic return signal from said transmitter to said second receiver;
• a second comparator that calculates a second measured comparison signal proportional to the difference in the time of flight of an acoustic return signal from said transmitter to said second receiver and the time of flight of an acoustic return signal from said transmitter to said third receiver;
• a distance comparator that calculates a measured distance comparison signal proportional to the time between emission of the acoustic signal by said transmitter and receipt of the return signal by at least one of said receivers;
• and
• means for adjusting the position of the robot arm so that the first measured comparison signal is equal to the first orientation command signal, and the second measured comparison signal is equal to the second orientation command signal, thereby establishing the angular orientation of the robot arm with respect to the surface, and so that the measured distance comparison signal is equal to the distance command signal, thereby establishing the distance of the robot arm from the surface.

Apparatus for positioning a movable portion of a robot device to a facing relationship with a surface, comprising:

• means for emitting from the movable portion a broad beam acoustic signal covering a spherical angle about the movable portion which is to be brought into a facing relationship with the surface;
• means for receiving response signals, if any, resulting from the striking of the broad beam acoustic signal on the surface, said means for receiving being mounted on the movable portion of the robot device and including at least two receivers oriented to receive signals from different directions;
• means for detecting the presence of a received response signal in said means for receiving;
• and
• means for automatically adjusting the angular orientation of the movable portion of the robot device by rotating the movable portion in accordance with the signals by the receivers of said means for receiving to a position such that a plane containing the two receivers is approximately perpendicular to a line that is perpendicular to the surface.