PURPOSE: To avert the inadequacy of positioning control in consequence of use of an erroneously detected speed (or position) at the time of executing positioning control.
CONSTITUTION: This positioning device has a control section 105 which controls a control object 101 (reading head driving motor) by calculating a controlled variable in accordance with the difference between the target speed determined by the detection position detected by a speed detecting section 103 and a target position and the detection speed of a reading head detected by a speed detecting section 102. The positioning device described above has an estimation section 106 which is inputted with the controlled variable and the detection position or detection speed, estimates the present position of the reading head or the present speed of the reading head and outputs the estimated value and a judgment section 107 which compares the detection position or detection speed and the estimated value and judges the detection position or detection speed as an abnormal value if the difference is larger than the prescribed value.
KAMOSHITA MIKIO
TAKAHASHI MINORU
