Patent ID: 8872064

Claim:
A positioning control system for positioning a moving element on a basis of position command data and being provided with a feedback loop, comprising: a loop gain modifier for changing an existing coefficient α of loop gain at a discrete time in a constant sampling cycle, wherein first a new correction value Mn is obtained from the following formula: Mn=M +( O max− NOv )· KP where M is a stored correction value, Omax is a measured maximum overshoot, NOv is a predetermined nominal overshoot, and KP is a coefficient; and then the existing coefficient α of the loop gain is changed by calculating a new coefficient α with the new correction value Mn from the following formula: α=1 +Mn; wherein said loop gain modifier changes the existing coefficient α of the loop gain when an absolute value s of the position command data is in a range H≧s≧h, where h is a predetermined first acceptance value, and H is a predetermined second acceptance value, but not when the absolute value s of the position command data is not in said range.