Meander control system, and meander control method

A meander control method of controlling amount of meander of a sheet object by using:

• a guide roller that is disposed on an intermediate portion of a conveying path of a sheet-like object, and that alters conveying direction of the sheet-like object by moving in contact with the sheet-like object conveyed along the conveying path;
• a first meander amount sensor which is disposed at a first detection position that is at an upstream side of the guide roller along the conveying path, and which detects amount of meandering of the sheet-like object at the first detection position;
• and a second meander amount sensor that is disposed at a second detection position between the first meander amount sensor and the guide roller on the conveying path, and that detects the amount of meandering of the sheet-like object at the second detection position, the meander amount control comprising:
• an error calculation step of calculating an error contained in a first gain of a first feedforward model in which the amount of meandering of the sheet-like object at the second detection position is estimated based on the amount of meandering of the sheet-like object at the first detection position, based on a detected value from the first meander amount sensor and a detected value from the second meander amount sensor;
• a gain correction step of correcting by the error a second gain of a second feedforward model in which the amount of meandering of the sheet-like object at a guide position that is a position at which the sheet-like object contacts the guide roller is estimated based on the amount of meandering of the sheet-like object at the second detection position;
• a guide position-estimated meander amount calculation step of calculating a guide position-estimated amount of meandering that is an estimated value of the amount of meandering of the sheet-like object at the guide position based on the second feedforward model that employs the second gain corrected by the error, and on the detected value from the second meander amount sensor;
• a cancel-out movement amount calculation step of calculating an amount of cancel-out movement based on the guide position-estimated amount of meandering, and a pre-set relation between the amount of meandering of the sheet-like object at the guide position and the amount of cancel-out movement that is an amount of movement of the guide roller for cancelling out the amount of meandering at the guide position;
• and
• a command signal sending step of sending to the guide roller a command signal for causing the guide roller to move by the amount of cancel-out movement calculated.