Control system and information recording and reproducing apparatus

A control system which generates a desired value intermittently and controls an object which performs a mechanical operation, comprising:

• a controlling element for adjusting a control input to be applied to said object to be controlled based on an input control;
• a detector for supplying a relative difference between a control variable of said object to be controlled and the desired value to said controlling element during a detection period in which a desired value is generated;
• object simulation means for estimating the control variable of said object to be controlled and outputting the controlled variable estimated signal based on the control input to be instructed to said object to be controlled;
• target follow-up estimation means for estimating a desired value of said controlled variable based on the relative difference and the controlled variable estimated signal and outputting a desired follow-up estimated signal;
• target stand-by generation means for generating a target stand-by signal indicative of a target to be followed of a controlled variable in other non-direction period based on the desired follow-up estimated signal in said detection period;
• and comparison means for supplying a difference signal between the target stand-by signal and the controlled variable estimated signal to said controlling element in the non-detection period.

An information recording and reproducing apparatus, comprising;

• a signal recording and reproducing part for performing at least either one of a recording operation and a reproducing operation with respect to a recording medium on which tracks are formed;
• an actuator for moving said signal recording and reproducing part;
• a controlling element for adjusting a control input to be applied to said actuator;
• actuator simulation means for estimating a position of said signal recording and reproducing part based on the control input to be instructed to said actuator and outputting an estimated position signal;
• and
• comparison means for inputting a difference signal between the desired value indicative of a desired position of said signal recording and reproducing part and the estimated position signal to said controlling element.

A control system for controlling an object which performs a mechanical operation, comprising:

• a detector for detecting a relative error between a controlled variable of said object to be controlled and a desired value,
• a controlling element having a positive feedback loop through a filter for adjusting a controlled input to be applied to said object to be controlled based on the relative error,
• said object to be controlled is a second-order lag element having a resonance, and
• said controlling element includes a phase compensation part for compensating for a phase-lead in a higher frequency band than a resonance frequency of said object to be controlled.