| 摘要 |
To maintain control of arc position in travel along a predetermined welding path, wherein the arc or equivalent heat source is given at least a minimal lateral reciprocation, an electrical characteristic, such as current, is sampled to obtain a continuous signal containing a component which varies with lateral position of the heat source. The first signal is also sampled at the extreme lateral positions of the arc to obtain comparable signal elements which are accumulated, amplified, compared with each other and/or with reference signals, and resultant outputs are used to initiate corrective action. This action may involve giving warning to a human operator or it may involve partial or full control of a physical or mechanical correction procedure. A general application is to the welding of a groove formed between adjacent work pieces. A more specific application is to weld joints involving narrow gaps between length of large pipe in pipeline building. The invention is applicable also to situations wherein lateral oscillation is not really required for gap filling but is used merely as a means to isolate control signals for maintaining an accurate center or main line travel position of the arc of heat source. Moreover, the invention may have a more general application, wherever guidance is desired along a main path that contains any element that effects signal amplitude of a probe characteristic relative to the lateral position of the element where the signal may be masked by noise.
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