Servo control system

A servo control system having a proportional (P) or a proportional plus an integral (PI) position controller, which output signal represents an input speed reference signal for a speed close loop system with a speed controller detecting a speed deviation, derived from a speed feedback loop, which output signal represents an input current reference signal for a current close loop system with a current controller detecting a current deviation, derived from a current feedback loop, which controls an amount of the current flowing through a motor, comprising:

• a first means to provide a reduced input position reference signal;
• a second means for producing a deviation signal, which represents a deviation between the reduced input position reference signal obtained by said first means and a feedback position signal obtained from a position sensor;
• a third proportional controller means connected in series with said second means to produce a proportional part for the input speed reference signal;
• a fourth means for producing a deviation signal which represents a deviation between the input position reference signal and the feedback position signal obtained from a position sensor;
• a fifth integral controller means connected in series with said fourth means to produce an integral part for the input speed reference signal;
• a sixth summing unit, which sums the signals produced by said third proportional controller means and by said fifth integral controller means and represent the input speed reference signal for a speed feedback close loop system;
• wherein the difference between the desirable input position reference signal and the reduced input position reference signal obtained by said first means define how much of the said fifth integral controller means correspondently to the said third proportional controller means can be applied to position the servo motor to the desired position with the specify characteristics.