A base material conveying device, comprising:
- an unwinding roll on which a base material in the form of an elongated band is wound;
- a first driver which rotationally drives the unwinding roll to unwind the base material wound on the unwinding roll:
- a conveyor which conveys the base material unwound from the unwinding roll;
- a conveying distance meter which measures a conveying distance of the base material unwound from the unwinding roll and conveyed;
- a first diameter meter which includes a first sensor facing the base material wound on the unwinding roll and measures a plurality of first measured winding diameter values corresponding to the conveying distance by measuring a diameter of the base material wound on the unwinding roll a plurality of times by the first sensor at the time of conveying the base material by the conveyor;
- a value acquirer which obtains a first initial diameter value which is a value of the diameter of the base material wound on the unwinding roll before the conveyance of the base material by the conveyor is started and a thickness value of the base material;
- and
- a controller including:
- a winding diameter calculator which calculates a plurality of first calculated winding diameter values corresponding to the conveying distance by calculating the value of the diameter of the base material wound on the unwinding roll a plurality of times at the time of conveying the base material by the conveyor based on the first initial diameter value and the thickness value of the base material obtained by the value acquirer and the conveying distance measured by the conveying distance meter;
- a filter unit which smooths the plurality of first measured winding diameter values corresponding to the conveying distance by a first low-pass filter to extract a plurality of first smoothed winding diameter values corresponding to the conveying distance;
- a difference calculator which calculates a plurality of first differences corresponding to the conveying distance by performing an operation of calculating a difference between the first calculated winding diameter value and the first smoothed winding diameter value while compensating for a delay by the first low-pass filter for the plurality of first calculated winding diameter values and the plurality of first smoothed winding diameter values;
- and
- a corrector which corrects the plurality of first calculated winding diameter values corresponding to the conveying distance by the plurality of first differences corresponding to the conveying distance.