Patent ID: 7430403

Claim:
A hysteresis control method in a control system having a plurality of control sections which are input value operating variation widths having hysteresis control sections at both ends, comprising: setting an arbitrary reference value which serves as a reference for deciding an existing position of a control width in a control section; calculating a difference between an input value this time and the arbitrary reference value in the control section to which a preceding input value belongs; generating position information indicating a positional relationship between the input value this time and the arbitrary reference value in the control section to which the preceding input value belongs from a difference result calculated; determining a direction of increase/decrease from a control value of the control section to which the preceding input value belongs from the position information; calculating an input value variation width extending over the control sections from the difference result and the control width in the control section to which the preceding input value belongs; and calculating the control value for the input value this time from the input value variation width and the direction of increase/decrease.