Abstract: A apparatus for controlling an actuator including, an integrator circuit to generate an integrated signal to be represented by a back EMF voltage, a amount circuit to generate a amount signal to indicate the amount to raise or lower the integrated voltage, a direction circuit to generate a direction signal to raise or lower the back EMF voltage, a comparator circuit to compare said integrated voltage with the back EMF voltage, and a switch circuit to add and subtract the amount signal with the integrated voltage in accordance with the direction signal.

Abstract: A apparatus for controlling an actuator including, an integrator circuit to generate an integrated signal to be represented by a back EMF voltage, a amount circuit to generate a amount signal to indicate the amount to raise or lower the integrated voltage, a direction circuit to generate a direction signal to raise or lower the back EMF voltage, a comparator circuit to compare said integrated voltage with the back EMF voltage, and a switch circuit to add and subtract the amount signal with the integrated voltage in accordance with the direction signal.

Abstract: An apparatus for controlling an actuator in response to a target speed voltage signal, the actuator having a moveable member and having a coil that influences movement of the member. A first summing node is provided having a control output voltage, for summing or subtracting voltages applied thereto, as the case may be and receiving the target speed voltage signal at a first, summing input thereto. A proportional compensation unit is provided, receiving the control output voltage and providing as an output a proportionally compensated output signal. An integral compensation unit is provided, receiving the control output voltage and providing as an output an integrally compensated output signal. An inverse compensation unit is provided, receiving the target speed voltage signal as an input and providing an inversely compensated output signal having a voltage corresponding to the voltage of the target speed voltage signal multiplied by the inverse of a predetermined amplification factor.

Abstract: An apparatus for controlling an actuator having a moveable member and having a coil that influences movement of the member, by provision of a drive current to the coil in response to a target speed voltage signal. The invention includes an up/down counter, counting at a predetermined count rate and providing a count output. A control unit is provided for controlling the direction of count of the up/down counter depending on whether the voltage across the coil, sensed periodically a first predetermined interval after the drive current to the coil is interrupted, is greater than, or less than, a reference voltage having a predetermined relationship to the target speed voltage. A digital-to-analog converter is provided, responsive to the count output to provide a compensated voltage signal having a voltage corresponding to the count output.