Patent ID: 6738218
Filing Date: 2004-05-18
Classification: G11B

Abstract:
A recording and reproducing device comprising:a storage medium for recording data therein; a head for recording and reproducing data in and from the storage medium; a position detection circuit for detecting a position of the head; a subtracter for calculating a position deviation signal on the basis of an output of the position detection circuit and a target position signal; a speed detector for calculating a speed of said head and outputting a speed signal; a speed controller for outputting a drive signal to move said bead in response to said speed signal and said position deviation signal; a position controller for outputting a drive signal of a linear function to position said head at a target position on a basis of said position deviation signal; a switching judger for performing a switching operation from the speed controller to the position controller; a target position signal generator for outputting a target position signal of a ternary-order function with an inverted value of said position deviation signal as an initial value after the changeover to the position controller; a feedforward signal generator for outputting a feedforward signal of a linear function with a proportional value of the position deviation signal after change-over to a positioning controller as an initial value; a first adder for adding said target position signal to said position deviation signal and outputting its added result as a new position deviation signal; a second adder for adding said feedforward signal to a drive signal as an output of a positioning compensator and outputting its added result as a new drive signal; and an initial value setter for causing state variables of the positioning compensator to be cleared to zeros before the positioning compensator receives the position deviation signal.