Control method of a leveling machine and leveling machine

A machine configured to level a sheet material, the machine comprising:

• a first group of work rolls and a second group of work rolls, the second group of work rolls being located forward of the first group of work rolls in relation to a forward movement direction of the sheet material, the first group of work rolls and the second group of work rolls being configured such that the sheet material follows a first winding path through the first group of work rolls and a second winding path through the second group of work rolls when the sheet material is advanced in the forward movement direction though the leveling machine;
• a first motor for driving the first group of work rolls to cause the sheet material to follow the first winding path;
• a second motor for driving the second group of work rolls to cause the sheet material to follow the second winding path, the second motor being independent from the first motor:
• a first sensor for measuring a rotational speed (V1) of a shaft of the first motor;
• a second sensor for measuring a rotational speed (V2) of a shaft of the second motor;
• a controller that is operatively coupled to the first and second sensors, the controller configured to control the rotational speed (V1) of the shaft of the first motor by means of a first torque setpoint signal (T1*) which is a function of a first error signal (e1) obtained from a difference between a setpoint rotational speed (V*) and the rotational speed (V1) of the shaft of the first motor, the controller configured to control the rotational speed (V2) of the shaft of the second motor by means of a second torque setpoint signal (T2*) which is a function of a second error signal (e2) obtained from a difference between the setpoint rotational speed (V*) and the rotational speed (V2) of the shaft of the second motor, the second torque setpoint signal (T2*) also being a function of an additional torque gain.