Patent ID: 7397628

Claim:
A position control method for controlling a position of an object to a target position by an actuator, comprising: a step of computing a position error based on a target position of the object and a current position of the object; a step of correcting an estimated position in a current sample by an estimated position error between said position error and an estimated position in a current sample of a current observer; a step of computing a difference between the corrected estimated position and a target trajectory in the current sample; a step of computing an estimated position advanced by a predetermined time from the sample point of time based on an output value in one sample before and the difference; a step of computing an output value to the actuator based on the advanced estimated position; and a step of computing an estimated position for the next output value computation based on the corrected estimated position, the output value in the current sample, and the output value in one sample before.