Rolling mill second flow thickness control method and device and electronic equipment

The invention discloses a rolling mill second flow thickness control method and device and electronic equipment. The method comprises the steps that whether the working state of a tachymeter on any side of a target rack on a rolling mill is a fault or not is judged; if the working state of the tachymeter on any side of the target rack is a fault, obtaining the speed measurement value of an inlet turning roller motor, the speed measurement value of an outlet turning roller motor and the strip steel thickness deviation value detected by an inlet thickness gauge of the target rack; and finally, according to the obtained speed measurement of the inlet turning roll motor and the outlet turning roll motor of the target rack and the strip steel thickness deviation value detected by the inlet thickness gauge, the roll gap position variable quantity of the second flow of the target rack is determined and obtained so as to control the rolling thickness of the rolling mill. Thus, when the speed measuring instrument brea