Drive device and method for controlling the drive device
A drive device includes a noise signal calculation unit, a signal correction unit, and a drive controller. The noise signal calculation unit calculates a noise signal corresponding to a magnetic flux generated from a current flowing through a drive coil. The signal correction unit corrects a detection signal detected by a detector based on the noise signal. The drive controller controls a drive signal to be applied to the drive coil based on a corrected signal obtained by the signal correction unit. The noise signal calculation unit acquires an amplitude of a predetermined frequency band including a frequency of a high-frequency drive signal, and calculates the noise signal included in the detection signal based on the acquired amplitude.
1. A drive device comprising:
a fixed frame on which one of a drive coil and a magnet facing the drive coil is disposed;
a movable frame on which another one of the drive coil and the magnet is disposed and which is movable relative to the fixed frame;
a detector that is disposed on one of the fixed frame and the movable frame on which the drive coil is disposed, and that detects and outputs a detection signal corresponding to a magnetic flux of the magnet;
a noise signal calculation unit that calculates a noise signal corresponding to a magnetic flux generated from a current flowing through the drive coil;
a signal correction unit that corrects the detection signal detected by the detector based on the noise signal; and
a drive controller that controls, based on a corrected signal obtained from correction by the signal correction unit, a drive signal to be applied to the drive coil and that drives the movable frame to a position corresponding to the corrected signal,
wherein
from the detection signal detected by the detector when a drive signal, in which a high-frequency drive signal is superimposed on a drive current to drive the movable frame, is applied to the drive coil, the noise signal calculation unit acquires an amplitude of a predetermined frequency band including a frequency of the high-frequency drive signal, and calculates the noise signal included in the detection signal based on the acquired amplitude.
2. The drive device according to claim 1 , wherein:
the noise signal included in the detection signal is represented by a product of the current I flowing through the drive coil and a false position signal coefficient G; and
where an amplitude of the high-frequency drive signal is represented by A and the acquired amplitude of the predetermined frequency band is represented by H, the false position signal coefficient G is expressed by: G=H/A.
3. The drive device according to claim 2 , wherein: where the corrected signal is represented by H′, the corrected signal H′ relative to a detection signal B that is uncorrected and acquired by the detector is expressed by: H′=B−I×G.
4. The drive device according to claim 1 , further comprising: an imaging element that is disposed in the movable frame and that generates a video signal relating to an object; and a display unit that displays an image based on the video signal,
wherein the predetermined frequency of the high-frequency drive signal is a frequency that makes an amount of movement of the movable frame fall within a range of one pixel of the imaging element.
5. The drive device according to claim 1 , further comprising: an imaging element that is disposed in the movable frame and that generates a video signal relating to an object; and a display unit that displays an image based on the video signal,
wherein when the false position signal coefficient G has a value out of a predetermined range, the noise signal calculation unit displays an error notification that the current I flowing through the drive coil is uncorrectable.
6. A method for controlling a drive device comprising: a fixed frame on which one of a drive coil and a magnet facing the drive coil is disposed; a movable frame on which another one of the drive coil and the magnet is disposed and which is movable relative to the fixed frame; and a detector that is disposed on one of the fixed frame and the movable frame on which the drive coil is disposed, and that detects and outputs a detection signal corresponding to a magnetic flux of the magnet, the method comprising:
applying a drive signal, in which a high-frequency drive signal is superimposed on a drive current to drive the movable frame, to the drive coil;
acquiring an amplitude of a predetermined frequency band including a frequency of the high-frequency drive signal from the detection signal detected by the detector;
calculating a noise signal included in the detection signal based on the acquired amplitude;
correcting the detection signal detected by the detector based on the noise signal; and
controlling, based on a corrected signal obtained from the correcting, a drive signal to be applied to the drive coil and driving the movable frame to a position corresponding to the corrected signal.