A vision-based penetration controller for application to varying root thickness

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:115468

Yidan, L; Richardson, R W

A penetration control system for autogenous gas tungsten arc welding (GTAW) has been investigated which has been shown to control root penetration in 304 stainless steel over a thickness range of 0.040 in. (1mm) to 0.125 in. (3 mm). A video system and computer vision processing are used to sense the width of the gas tungsten arc (GTA) weld pool. Variation in thickness of the joint root is a very common problem in many practical applications where weld joints are prepared on cast metal components. The control method here uses a relationship between current and pool width to estimate the thickness of the plate from a model. That is, a certain weld pool width and current indicate a particular thickness of material. A relatively high current and a relatively small width indicate thick material, and a relatively low current and large width indicate thin material. A theoretical heat flow model for thin plate has been utilized to investigate this dependence numerically. The basic idea is that if a relatively high current is required to produce a relatively small width, then a suitably larger width set point is utilized for purposes of feedback control than if the opposite occurs. The details of the fuzzy control and the results of experiments are described.

• OSTI ID: 115468
• Report Number(s): CONF-9404233--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COMPUTER-AIDED MANUFACTURING
COMPUTERIZED CONTROL SYSTEMS
FUZZY LOGIC
GAS TUNGSTEN-ARC WELDING
STAINLESS STEEL-304