Controlled pin insertion using airflow sensing and active feedback
First Claim
1. An automatic assembly system for inserting a pin in a hole in a plate, characterized by:
- (a) control means (4) for positioning pin (1) laterally in the vicinity of a selected hole (2) in the plate (3), in position within the detection region (9) of the hole (2);
(b) fluid flow means (11) associated with the plate (3), to form a pressure differential creating fluid flow (7)through at least one hole in the plate (3), including said selected hole (2);
(c) fluid flow sensing means (6), associated with said control means (4) for positioning the pin (1) to sense the fluid flow (7) at the selected hole (2) and to supply force vector signals indicative of such forces;
(d) servo means, responsive to feedback from said fluid flow sensing means (6) to said control means (4), to supply information for positioning the pin (1) within the detection region of the selected hole at the insertion point (10) which is within the capture region of the selected hole (2) as defined by the composite of mechanical and virtual chamfers determined by a change of the force vector signals related to the null where lateral forces (7) of fluid flow through the selected hole (2) balance over the selected hole (2);
whereby the system provides power steering of the pin (1) to the insertion point (10) for the selected hole (2).
1 Assignment
0 Petitions
Accused Products
Abstract
An automatic assembly apparatus or robot holds a pin in an instrumented gripper, moves open loop to the "detection region" in which airflow forces, primarily lateral forces, in the vicinity of the hole may be dependably sensed. Relatively large lateral airflow forces in the detection region are sensed and the pin is moved toward the hole. The airflow forces exhibit an abrupt force change as the pin reaches the insertion point within the "capture region" of the hole defined by the mechanical chamfer or significantly extended as a result of the virtual chamfer of airflow through the hole. The insertion point is the point where lateral X,Y force vectors balance to a null, where Z force readings change from complex X,Y,Z force vectors to simple Z force vectors. The controller commands an open loop move to place the pin within the detection region; then commands a closed loop move, using a skirt around the pin or the pin itself as a probe, and sampling the force vectors until the insertion point is detected; then commands a move in the Z direction to put the pin into the hole. Insertion success or failure is detected by sampling the Z force vectors for blockage by the plate, or by sampling pressure as the pin plugs the hole. Retry routines follow detection of any insertion failure.
37 Citations
15 Claims
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1. An automatic assembly system for inserting a pin in a hole in a plate, characterized by:
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(a) control means (4) for positioning pin (1) laterally in the vicinity of a selected hole (2) in the plate (3), in position within the detection region (9) of the hole (2); (b) fluid flow means (11) associated with the plate (3), to form a pressure differential creating fluid flow (7)through at least one hole in the plate (3), including said selected hole (2); (c) fluid flow sensing means (6), associated with said control means (4) for positioning the pin (1) to sense the fluid flow (7) at the selected hole (2) and to supply force vector signals indicative of such forces; (d) servo means, responsive to feedback from said fluid flow sensing means (6) to said control means (4), to supply information for positioning the pin (1) within the detection region of the selected hole at the insertion point (10) which is within the capture region of the selected hole (2) as defined by the composite of mechanical and virtual chamfers determined by a change of the force vector signals related to the null where lateral forces (7) of fluid flow through the selected hole (2) balance over the selected hole (2); whereby the system provides power steering of the pin (1) to the insertion point (10) for the selected hole (2). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for pin-in-hole insertion by a robot comprising the steps of:
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(a) applying airflow through at least the selected hole (2) for insertion of a pin (1), creating a pattern of detectable airflow forces (7) within a detection region about the hole (2); (b) moving the pin (1) by open-loop positioning to place within the detection region; (c) sensing the airflow by airflow sensing means (6,16) closely associated with the pin (1); (d) following the airflow-forces sensed by the airflow-sensing means (6,16) by closed-loop positioning through at least one sensing and airflow-following servo move in the (x,y) direction of changing lateral airflow force, thus moving the pin (1) toward the hole (2); (e) repeating said sensing the airflow step (c) and said following the airflow-forces step (d) until an airflow null is sensed defining the insertion point 10 at the capture region of the hole (2); and (f) commanding an entry move (z direction) of the pin (1) into the selected hole (2) at the insertion point (10) which is within the composite mechanical/virtual chamfer capture region of the hole (2). - View Dependent Claims (14, 15)
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Specification