POSITIONING CONTROLLER

摘要

PURPOSE: To make a head position highly accurately follow up a position track and a speed track even for the saturation of a VCM (voice coil motor) current as to the positioning system of a magnetic disk unit. CONSTITUTION: Internal models 42 to 44 and a track generation part 40 are structure in a control program and a model control part 41 calculates a 1st operation signal Umf and a 2nd operation signal Ums so that an operation signal for outputting the Ums for a fixed sample time Tu after the Umf outputted for the fixed sample time Tu matches a position track and a speed track where a position Pm and a speed Vm outputted by an internal model 2xTu second later are formed. When a detector 48 detects the saturation of a voice coil current for head movement, the signal obtained by subtracting a position feedback signal Uh from the detected voice coil current is inputted to the internal model to make the model follow up the controlled system, thereby preventing deterioration in control performance.