Position controlling apparatus capable of reducing the effect of disturbance

A position controlling apparatus comprising:

• a position detector for detecting a position of a driven object to be driven by a motor to the thereafter output a detected value of position;
• a Kalman filter for estimating the position and velocity of the driven object from the detected value of position to thereby output an estimated value of position and an estimated value of velocity;
• a disturbance estimating unit for estimating disturbance applied to the driven object by comparison with a command value of current and the estimated value of velocity to thereby output an estimated value of disturbance;
• a first substracter for computing a difference between a command value of position and the estimated value of position;
• a position controller for computing a command value of velocity in accordance with the difference computed by the first subtracter;
• a second subtracter for computing a difference between the estimated value of velocity and the command value of velocity;
• a velocity controller for computing a target value of current in accordance with the difference computed by the second subtracter;
• and
• a third subtracter for computing a difference between the estimated current value of disturbance and the target value of current to thereby output the difference as the command value of current, whereby the command value of current is applied to the disturbance estimating unit and a motor drive for driving motor, wherein
• a position controlling apparatus wherein the Kalman filter performs the operation that is given by the following equation:
• [ x ep ⁡ ( k ) x ev ⁡ ( k ) ] = [ 1 T s 0 1 ] [ ⁢ x ep ⁡ ( k - 1 ) x ev ⁡ ( k - 1 ) ] + [AutoLeftMatch] [ K 1 K 2 ] ⁢ [AutoLeftMatch] [ ⁢ x m ⁡ ( k ) - [ 1 T s ] ⁡ [ x ep ⁡ ( k - 1 ) x ev ⁡ ( k - 1 ) ] ] ( 1 )