Predictive repetition control method for a servo motor and an apparatus therefor

A predictive repetition control method for a servo motor, using control apparatus for controlling a servo motor in accordance with a move command P repeatedly supplied at intervals of a predetermined period, comprising the steps of:

• receiving the move command P to generate an output p delayed from the move command P by N sampling time periods, which are determined by an order N obtained by identifying a control object G.sub.0 ;
• executing processing of a feedback controller to generate a first control output v on the basis of the output p and a feedback deviation amount .epsilon. associated with a moving amount of the servo motor;
• providing a feedforward controller including a FIR-type digital filter;
• determining said feedback deviation amount .epsilon. based on a positional deviation between the output p and a position feedback amount .omega.;
• executing processing of said feedforward controller to receive the move command P and the feedback deviation amount .epsilon., to automatically determined coefficients of said FIR-type digital filter by adaptive control based on said received move command P and said feedback deviation amount .epsilon. and to generate a second control output u as a transfer function Z.sup.-N /G.sub.0 ' which functions as an inverse system for the control object;
• and
• controlling the moving amount of the servo motor on the basis of the first and second control outputs.

A predictive repetition control apparatus for controlling a servo motor in accordance with a move command repeatedly supplied at intervals of a predetermined period, comprising:

• delay means for receiving a move command P and for generating an output p delayed from the move command P by N sampling time periods, which are determined by an order N obtained by identifying a control object G.sub.0 ;
• feedback detecting means for determining a feedback amount .omega. associated with a moving amount of the servo motor;
• feedback control means for generating a first control output v on the basis of the output p from the delay means and the feedback amount .omega. from the feedback detecting means;
• deviation means for determining a positional deviation .epsilon. between the output p and the feedback amount .omega.;
• feedforward control means, including a FIR-type digital filter, for receiving the move command P and the determined positional deviation .epsilon., for automatically determining coefficients of said FIR-type digital filter based on said received move command P and determined positional deviation .epsilon., and for generating a second control output u as a transfer function Z.sup.-N /G.sub.0 which functions as an inverse system for the control object;
• and
• moving amount control means for controlling the moving amount of the servo motor on the basis of the first and second control outputs.