Fuzzy controller for an actuator and the controlling method thereof

A fuzzy controller for an actuator, comprising:

• a first error generation unit for outputting a position error value with inputs of a present position value of said actuator and a reference value from an external input unit for controlling said actuator;
• a first switching unit for switching a track following operation to a track seeking operation or vice versa to control said actuator according to a result of a comparison of said position error value and a first predetermined value;
• a first control signal generation unit for generating a track following operation control signal for said track following operation of said actuator based on said position error value inputted according to a switching operation of said first switching unit;
• a velocity error generation unit for generating a velocity error value by calculating a difference between a target velocity value and an actual velocity value, wherein said target velocity value is determined based on said position error value inputted according to said switching operation of said first switching unit and said actual velocity value is calculated through an arithmetic operation;
• a second switching unit for switching an acceleration control to a deceleration control or vice versa for said actuator by comparing said velocity error value with a result of an arithmetic operation between a second predetermined value and said actual velocity value;
• a second control signal generation unit for generating an acceleration control signal for accelerating said actuator by adding said velocity error value inputted according to a switching operation of said second switching unit and a track position error integration value obtained from an integration of track position error values, wherein said track position error values are indicative of values occurring when said actuator is off-track from the center of a track and said integration of track position error values occurs at every sampling;
• and
• a third control signal generation unit for generating a deceleration control signal for decelerating said actuator by performing an arithmetic operation between a fuzzy inference value generated according to fuzzy rules based on said velocity error value inputted according to a switching operation of said second switching unit and a differential velocity error value, said track position error integration value, a third predetermined value and said actual velocity value.