Online intelligent preventive repair method for roll surface of pinch roll of coiling machine

The invention relates to the field of online intelligent preventive repair of the roll surface of a pinch roll of a coiling machine. An on-line intelligent preventive repair method for the roll surface of a pinch roll of a coiling machine comprises five repair modes: in the first repair mode, working clearance repair is performed, specifically, when a load relay of the coiling pinch roll is OFF, a mold repair device arrives at a working position to start to repair the pinch roll, and after a load relay of a next strip steel on a finish rolling tail rack is ON, the mold repair device arrives at the working position to start to repair the pinch roll; the die repairing device stops the pinch roll repairing and leaves the working position to the waiting position; in the second repairing mode, the die is repaired in the process downtime; in the third repairing mode, when a fault occurs, the mold is repaired after the fault is removed; according to the fourth repairing mode, when the surface detector detects that t