Position control of optical head in a recording device

A data scanning device in which a data scanning head is positioned relative to a data medium, comprising:

• a driving mechanism for moving the data scanning head with an adjustable speed;
• a monitoring device for measuring an instantaneous speed and position of the data scanning head;
• a calculator for calculating a desired head speed as a function of a position of the scanning head;
• a regulating circuit for regulating the adjustable speed to the desirable head speed;
• wherein the driving mechanism moves the data scanning head in steps of a determined step length, a number of steps moved corresponding to an amount of energy provided to the driving mechanism;
• and,
• a controller controls the regulating device to output a quantified amount of energy to the driving mechanism to move a number of steps separating the instantaneous position and a determined final position of the data scanning head.

A method for positioning from a third position to a second position a data scanning head in a data scanning device using a step motor which moves the scanning head in steps, comprising the steps of:

• calculating a final number of steps between the third position and the second position;
• outputting to the step motor a quantified amount of energy corresponding to the final number of steps;
• determining a near position of the data scanning head rafter the outputting of the quantified amount of energy;
• calculating a last number of steps separating the near position from the second position;
• and,
• outputting a second quantified amount of energy corresponding to the last number of steps to be moved if the last number is greater than a predetermined value.

A method for positioning a data scanning head in a data scanning device from a first position to a second position, comprising the steps of:

• calculating a desirable head speed for the data scanning head for intermediate positions between the first and the second position,
• measuring an instantaneous position and speed of the data scanning head during movement between the first and the second position,
• regulating a speed of the data scanning head to the desirable head speed;
• moving the data scanning head in steps;
• stopping regulating when the data scanning head has reached the second position;
• determining a third position of the data scanning head,
• calculating a final number of steps between the third position and the second position,
• outputting to a step motor a quantified amount of energy corresponding to the final number of steps to be moved;
• determining a near position of the scanning head after outputting the quantified amount of energy;
• calculating a last number of steps separating the near position from the second position;
• and,
• outputting to the step motor a second quantified amount of energy corresponding to the last number of steps to be moved if the last number is greater than a predetermined value.