The invention relates to an automatic
voltage regulation (AVR) singlechip control-based thick wire electric-gas vertical
welding machine and a control method. The
welding machine comprises a three-way trolley travelling set circuit, a swing front and back stop set circuit, a swing amplitude and speed set circuit, a
welding torch centering swing
control set circuit, a welding start / end
control circuit, a digital display circuit, a welding
mode selection control circuit, a welding start / stop
control circuit, an optocoupler isolation circuit, a travelling
motor control drive circuit, a swinging
motor control drive circuit and a motor
voltage current feedback circuit. In the method, welding
voltage is sampled to serve as a
feedback control signal of automatic climbing of a trolley and the change of wire feeding speed; when the
arc length is increased by interference in the automatic
welding process, the
arc voltage is increased and the wire feeding speed is increased, so that the
arc length is reduced, and the speed of a climbing
direct current servo motor is reduced, so that the
arc length is reduced; when the arc length is reduced by interference, the
arc voltage is reduced and the wire feeding speed is reduced, so that the arc length can be increased; and when the arc length is not changed in the automatic
welding process, the wire feeding speed and the travelling speed of the climbing trolley are not changed, so that the arc length is stable.