Penetration shape control with correction of the state variables evaluation during electron-beam welding by the level of active disturbances

Abstract

Penetration shape during electron-beam welding is determined in the first approximation by the vapour plasma crater shape formed by the energy source. The inability to measure the parameters of penetration shape during electron-beam welding leads to their estimation by regression equations that establish a relationship with mode parameters. However, when welding mode parameters are stabilized, the instability of penetration shape remains due to the action of uncontrolled disturbances, which in some cases lead to unacceptable deviations. A possibility of the state variables evaluation correction during electron-beam welding, namely the depth penetration and the weld shape factor, by determining the “noise component”, is considered. Such correction is carried out by the discrepancy of any measured output variable, as the difference between its estimate according to a similar mathematical model and the measured value. As such output variable, the vapour plasma torch light intensity can be used. A control algorithm and a structural diagram of the automatic control system for weld penetration shape with correction of model assessment of the process state by the measured output have been developed.