JP2020089094A - Motor drive device, control method thereof, and imaging device - Google Patents

Abstract

To provide a motor drive device capable of accurately stopping a rotor at a target position in a shorter time by performing deceleration stop of the rotor without performing switching from feedback drive to open-loop drive.SOLUTION: A motor drive device 100 performs first control where open-loop drive is performed by switching electric conduction to a coil of a motor 104a at predetermined time intervals, and second control where feedback drive is performed by switching the electric conduction to the coil of the motor 104a according to an output of a sensor that detects a position of a rotor. When the rotor is decelerated from a stationary speed (refer to V1) and is stopped at a target stop position TP, a control unit performs changing from an advance angle θ1 at the time of stationary drive to an advance angle θ2 at the time of deceleration when the position of the rotor has reached a first position through the second control, and performs changing to an advance angle θ3 when the position of the rotor has reached a second position. A rotor speed corresponding to a speed V2 at the time of drive by the advance angle θ3 is within a self-activation region for the open-loop drive.SELECTED DRAWING: Figure 8

Description

The present invention relates to a deceleration/stop control technique by feedback driving using a rotation detection sensor of a rotor.

As a drive control method of the motor, there is a method of performing feedback drive (hereinafter also referred to as FB drive) after the synchronous operation. After synchronous operation is performed at the drive frequency determined at the time of startup, FB drive is performed based on the detection signal of the sensor that detects the rotational phase of the rotor, and acceleration, constant speed, and deceleration operations are performed as necessary. Is done. When stopping, first, deceleration control is performed in the FB drive, and then open loop drive (hereinafter also referred to as OL drive) in the synchronous operation mode is performed, and then stop control to the target position is performed.

Patent Document 1 discloses a motor drive device that reduces vibrations that occur when switching from FB drive to OL drive. The motor drive device includes drive means for performing OL drive and FB drive of the motor, respectively, and the calculation means calculates the rotational frequency and the angular acceleration of the rotor magnet from the output of the position sensor. The control means controls acceleration, constant speed, and deceleration of the rotor magnet by FB drive, then switches from FB drive to OL drive, and further performs deceleration control of the rotor magnet. When the FB drive is switched to the OL drive, control is performed so that the rotation frequency and the angular acceleration calculated by the calculation unit approach the initial rotation frequency and the initial angular acceleration during the FB drive, respectively.

JP, 2011-97720, A

In the related art, if the FB control before the transition from the FB drive to the OL drive is complicated and the control needs to be performed at high speed, the desired control becomes difficult. If the FB drive cannot be smoothly switched to the OL drive, a step out of the motor may occur. Further, when decelerating by OL drive, sudden stop from a high-speed rotation area outside the self-starting area may cause step-out.
An object of the present invention is to provide a motor drive device capable of stopping at a target position accurately in a shorter time by performing deceleration stop of a rotor without switching from FB drive to OL drive.

A motor drive device according to an embodiment of the present invention provides a first control for driving a motor by open loop control according to a drive waveform of a preset frequency, and a detection signal by a detection unit that detects the position of the rotor of the motor. It has a control means which acquires and determines the advance angle showing the phase relation of the stator of the motor, and the rotor, and performs the 2nd control which drives the above-mentioned motor by feedback control. In the second control, the control means stops the rotor at the target stop position when the rotor reaches a first position predetermined with respect to the target stop position. The deceleration control is performed with a second advance angle smaller than the first advance angle during steady drive, and the third speed control is performed when the rotor reaches a second position predetermined with respect to the target stop position. Drive with the advance angle of. The speed of the rotor when driven by the third advance angle is within the self-starting region when the motor is driven by the first control.

According to the present invention, it is possible to provide a motor drive device capable of accurately stopping at a target position in a shorter time by decelerating and stopping the rotor without switching from FB drive to OL drive.

It is a figure showing the schematic structure of the motor drive concerning the embodiment of the present invention. It is a figure showing the structure of a rotation angle detection means, a rotor magnet, and a stator. It is a block diagram showing an outline of a system configuration concerning an embodiment of the present invention. It is a figure showing the state where a rotor magnet phase and a drive waveform phase have a stable stop relation. It is a figure showing the relationship between a rotor magnet phase and a drive waveform phase (at the time of forward rotation torque generation). It is a figure showing the relationship (at the time of reverse rotation torque generation) between a rotor magnet phase and a drive waveform phase. It is a figure showing the relationship between a torque and an advance angle. FIG. 6 is a diagram illustrating a relationship between a moving speed of a lens holder and an advance angle when decelerating and stopping in the first embodiment. It is a figure showing the moving speed and advance angle of a lens holder at the time of deceleration stop in a 2nd embodiment. It is a figure showing the moving speed and advance angle of a lens holder at the time of deceleration stop in a 3rd embodiment. It is a figure showing the moving speed and advance angle of a lens holder at the time of deceleration stop in a 4th embodiment. It is a figure showing the moving speed and advance angle of a lens holder at the time of deceleration stop in a 5th embodiment. It is a figure showing the moving speed and advance angle of a lens holder at the time of deceleration stop in a 6th embodiment.

Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. INDUSTRIAL APPLICABILITY The motor drive device according to the present invention is applicable to drive a motor that drives an optical member included in an optical device such as an imaging device or an interchangeable lens.

[First Embodiment]
The configuration of the motor drive device 100 according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an exploded perspective view showing a main part of the motor drive device 100. The lens holder 101 is a holding member that holds the focus lens 101c, and is supported by the guide bars 102 and 103 so as to be slidable in the optical axis direction. In FIG. 1, the optical axis direction of the focus lens 101c is defined as the z-axis direction, and the z-axis and the x-axis and the y-axis orthogonal to the z-axis are shown.

The pair of guide bars 102 and 103 are guide members arranged along the optical axis direction and are incorporated in a lens barrel (not shown) to form a part of the image pickup optical system. The lens holder 101 has fitting hole portions 101a formed at two front and rear positions in the z-axis direction, and the guide bar 102 is fitted into the fitting hole portion 101a. Further, the lens holder 101 has a U-shaped groove portion 101b having a notch shape and is engaged with the guide bar 103. With this configuration, the lens holder 101 can be moved by being guided by the guide bars 102 and 103, and the guide bar 103 restricts the rotation of the lens holder 101 about the guide bar 102, so that the lens holder 101 can be stably moved in the optical axis direction. Is possible. In the present embodiment, the lens holder 101 holding the focus lens 101c moves in the optical axis direction to perform a focus adjustment operation for focusing on a desired position of the subject.

The stepping motor unit 104 includes a stepping motor (hereinafter, also simply referred to as a motor) 104a, a feed screw 104b having a screw formed on an outer diameter portion, and a support portion that supports a screw tip portion 104d of the feed screw 104b. It has a flange portion 104c. The driving direction of the motor 104a coincides with the optical axis direction.

The nut 105 is a connecting member in which a female screw 105a is formed, and the female screw 105a meshes with the feed screw 104b. When the flange portion 104c is attached to the motor 104a, the nut 105 is first engaged with the feed screw 104b, and is configured as a part of the motor unit 104.

The motor unit 104 includes a short cylindrical ENC (encode) magnet 104e at the end of the feed screw 104b. The ENC magnet 104e is magnetized so as to generate a sinusoidal magnetic field according to the rotation angle as a magnetic field generated on the circumference. The Hall element package 104f is arranged in the motor unit 104 at a position where the magnetic field of the ENC magnet 104e can be detected. In this embodiment, Hall elements 104fa and 104fb described later are used. The Hall elements 104fa and 104fb detect the change in the magnetic field due to the rotation of the ENC magnet 104e and output a detection signal at their respective positions. The rotation angle information of the feed screw 104b can be acquired by the ENC magnet 104e and the Hall element package 104f.

The biasing member 106 is fixed to the mounting portion 101x of the lens holder 101 with a screw 107. The biasing member 106 is integrally formed with a pressing portion 106a that biases the nut 105 in the optical axis direction, and a radial biasing spring 106b that biases the nut 105 in the radial direction (direction parallel to the y axis). Has been done. A mounting portion 101f of the nut 105 is formed on the lens holder 101, and the nut 105 is biased against the lens holder 101 by the pressing portion 106a. Regarding the fitting play generated between the feed screw 104b and the female screw 105a of the nut 105, the fitting play can be suppressed by urging the nut 105 in the radial direction by the radial urging spring 106b.

In the motor drive device 100, the biasing member 106 is used to connect the nut 105 and the lens holder 101 while suppressing the play between the feed screw 104b and the nut 105. With this configuration, the lens holder 101 can be moved along the optical axis for accurate positioning.

The configuration of the motor 104a will be described with reference to FIG. FIG. 2A is a schematic diagram showing the positional relationship between the ENC magnet 104e and the Hall elements 104fa and 104fb. The ENC magnet 104e is a 10-pole magnet. The N-pole and S-pole regions each have 5 poles and are magnetized in the 36-degree region. The Hall elements 104fa and 104fb are arranged equidistant from the center position of the ENC magnet 104e when viewed from the center position. The physical angle formed by the Hall elements 104fa and 104fb with respect to the center of the ENC magnet 104e is 18 degrees. The signal phase detected by the Hall element package 104f has a phase difference of 90 degrees. The positional relationship between the rotor and the stator will be described later with reference to FIG.

FIG. 3 is a diagram showing a system configuration including an electric circuit for driving the motor driving device 100. The amplifier 108 acquires and amplifies a weak signal from the Hall element package 104f (104fa, 104fb), and transmits the signal to the AD conversion circuit 109. The AD conversion circuit 109 performs AD conversion of the input voltage signal and outputs a digital numerical signal as a conversion result to the position ENC circuit 110. The position ENC circuit 110 adjusts the offset and gain of the two input signals. The position ENC circuit 110 generates the TAN (tangent) value from the two signals after the adjustment, and then performs the inverse TAN calculation, and integrates it to generate the rotation angle information. The generated rotation angle information is sent to the drive waveform generation circuit 111. The drive waveform generation circuit 111 determines drive waveforms to be applied to the A-phase coil 119 and the B-phase coil 120 of the motor 104a. The drive waveform generation circuit 111 switches between OL drive and FB drive according to a command from a CPU (Central Processing Unit) 112. In OL driving, sine wave signals with different driving phases are output at a preset frequency. Further, in the FB drive, a drive waveform signal linked with the position ENC circuit 110 is output.

The drive waveform signal generated by the drive waveform generation circuit 111 is sent to the motor driver 113. The motor driver 113 generates a sinusoidal voltage applied to the A-phase coil 119 and the B-phase coil 120 from the drive waveform signal and outputs the voltage to the motor 104a. This voltage corresponds to the energizing voltage for driving (see FIGS. 10 to 13: E1), and is expressed as an average voltage or a maximum voltage in the case of a sinusoidal voltage.

In this way, the amplifier 108, the AD conversion circuit 109, the position ENC circuit 110, the drive waveform generation circuit 111, the CPU 112, and the motor driver 113 form a motor drive circuit. The stator A+114 and the stator A-115 of the motor 104a function to concentrate and release the magnetic fields generated at both ends of the A-phase coil. The stator B+116 and the stator B-117 function to concentrate and release the magnetic fields generated at both ends of the B-phase coil. A specific example will be described with reference to FIG.

FIG. 2B shows the arrangement of the stator A+114, the stator A-115, the stator B+116, the stator B-117, and the rotor magnet 118. For example, the CW direction is the normal rotation direction of the motor 104a. The stator A+114, the stator A-115, the stator B+116, and the stator B-117 have a physical relationship of a physical angle of 18 degrees, and a total of five sets are arranged. The rotor magnet 118 is located in the center of the stator group, and has N poles and S poles each having 5 poles, and has a total of 10 magnetic poles. The rotor rotates by a physical angle of 72 degrees each time one sine wave of the drive waveform is output.

When the FB drive is switched by the CPU 112, the drive waveform generation circuit 111 generates a drive waveform of the motor 104a that gives an arbitrary phase difference to the rotation angle information of the rotor magnet 118 obtained from the position ENC circuit 110. The arbitrary phase difference is set according to the driving condition, and the CPU 112 determines the phase difference by comparing with the driving condition.

Next, the operation of the motor drive device 100 will be described with reference to FIGS. 4 to 6. FIG. 4(A) is a schematic view showing the stator group shown in FIG. 2(B) in an expanded state and arranged side by side. FIG. 4B is a diagram schematically showing what kind of voltage is applied to the stator group in the circumferential direction. FIG. 4C is a diagram showing the strength of the magnetic field corresponding to the circumferential position generated by the stator group by the voltage application of FIG. 4B. FIG. 4D is a diagram showing the magnetization phase of the rotor magnet 118 shown in FIG. 2B. The horizontal axis in each of FIGS. 4B to 4D represents the rotational position of the rotor. In the state shown in FIG. 4, the NS magnetic pole phase of the magnetic field generated by the stator group and the NS magnetic pole phase of the rotor magnet 118 have a relationship in which the rotor magnet 118 stops stably.

On the other hand, FIG. 5 shows a state in which the forward rotation torque is generated in the rotor magnet 118. FIGS. 5A to 5D correspond to FIGS. 4A to 4D, respectively. As shown in FIG. 5C, the magnetizing phase of the rotor magnet 118 is different from that of FIG. A magnetic field whose phase is advanced by 90 degrees compared to (C) is generated. As a result, an attractive force pulling to the right, that is, a rotational torque in the forward direction is generated in the rotor magnet 118 shown in FIG.

In the following, the phase difference showing the phase relationship between the magnetic field generated by the stator group and the magnetic field of the rotor magnet 118 is represented by an advance angle. It is assumed that the advance angle value in the phase relationship in the stable stop state shown in FIG. 4 is 0 degree, and the advance angle value in the phase relationship shown in FIG. 5 is +90 degrees. FIG. 6 shows a state in which a reverse rotation torque, that is, a torque in the direction opposite to the normal rotation direction is generated in the rotor magnet 118, and the advance value in this phase relationship is −90 degrees. FIGS. 6A to 6D correspond to FIGS. 4A to 4D, respectively, and a leftward force is generated in the rotor magnet 118 shown in FIG. 6D.

When the CPU 112 switches to the FB drive, it can control the drive of the motor 104a by generating a rotational torque by setting an arbitrary advance angle. As will be described later, by setting the advance angle value to 0 degree or a negative value during forward rotation, it is possible to generate a more rapid deceleration force and perform deceleration in a short time.

FIG. 7 is a graph showing the relationship between the advance angle and the rotation torque. The horizontal axis represents the advance angle (denoted by α), and the vertical axis represents the rotational torque (denoted by T). From 0 degrees, which is the advance value indicating the phase relationship in the stable stop state, the rotation torque T increases in the positive direction toward 90 degrees, and the advance value at which the stator group and the rotor magnet 118 repel each other and stop. The rotation torque T decreases toward 180 degrees. When the advance angle value exceeds 180 degrees, rotational torque (negative torque) in the reversing direction is generated.

A method of decelerating and stopping the lens holder 101 by driving the motor 104a will be described with reference to FIG. The horizontal axis represents the position of the lens holder 101 corresponding to the rotational position of the rotor magnet 118. The vertical axis represents the moving speed and the advance angle of the lens holder 101. FIG. 8 shows an example of changes in the moving speed of the lens holder 101 until the lens holder 101 decelerates from the steady speed V1 and stops at the target stop position TP, and changes in the advance angle. N1, N2, and TP indicate the positions of the lens holder 101 (N1<N2<TP). V1, V2, and V3 indicate moving speeds (V1>V3≧V2), and θ1, θ2, and θ3 indicate advance angles (θ1>θ3≧θ2).

First, in the constant speed control, the motor 104a rotates so that the lens holder 101 moves at the steady speed V1 along the optical axis. At this time, the voltage is applied to the stator group at the advance angle θ1 for generating the normal rotation torque. The advance angle θ1 is an advance angle during steady drive, and the speed of the rotor when driven at the advance angle θ1 is outside the self-starting region. The self-starting region means a frequency region corresponding to a range in which the stepping motor can be started and stopped without causing step out when a drive pulse having a certain frequency is applied. The area varies depending on the drive voltage and the load even for the same motor.

When the lens holder 101 reaches the predetermined first position N1, the control moves from the constant speed control to the deceleration control. In this case, the CPU 112 abruptly changes the advance angle from θ1 to θ2, so that the motor 104a starts deceleration. The advance angle θ2 is the advance angle during deceleration. In FIG. 8, the value of θ2 is zero, and the phase relationship between the magnetic field generated by the stator group and the magnetic field of the rotor magnet 118 is as shown in FIG.

The lens holder 101 continues to decelerate with the rotor magnet 118 kept in a state where no rotational torque is generated. At the time of deceleration, various loads (hereinafter referred to as various loads) such as a sliding load between the lens holder 101 and the guide bar 102 fitted to the lens holder 101 and a rotary sliding load between the nut 105 and the feed screw 104b. Thereby generates a braking force. Due to this braking force, the moving speed of the lens holder 101 gradually decreases. If this state continues, the lens holder 101 naturally stops, but the stop position varies depending on load conditions (environmental temperature, humidity, posture, etc.) at each time. Therefore, it is difficult to stop the lens holder 101 at an accurate position. Therefore, in the present embodiment, when the lens holder 101, which continues to decelerate, reaches the predetermined second position N2, the advance angle is changed from θ2 to θ3 and drive control before stop is performed. The motor 104a rotates due to the rotational torque generated at the advance angle θ3, and the lens holder 101 converges to the speed V2 and continues to move, but the rotational speed of the motor 104a at this time is equal to or lower than the speed within the self-starting region (boundary speed). (See V3). That is, in the motor 104a, the speed corresponding to V2 is set to be equal to or lower than the motor rotation speed corresponding to the moving speed V3 of the lens holder 101 shown in FIG.

When the rotation speed of the motor 104a is set to be equal to or lower than the rotation speed corresponding to the moving speed V3, the motor drive is further continued, and when the lens holder 101 reaches the target stop position TP, holding energization is performed. That is, the holding energization for maintaining the energization phase state at the time of reaching the target position is performed, and the motor drive is stopped. Since the rotation speed of the motor 104a at this time is within the self-starting region, even if the holding current is suddenly changed, step-out does not occur and the lens holder 101 can be stopped at an accurate target stop position. Become.

Regarding the distance difference between the first position N1 and the second position N2, which is predetermined with respect to the target stop position TP, the distance until the vehicle is stopped by abruptly changing the advance angle from θ1 to θ2 is expressed as D1. Is set so that N2-N1≤D1. This can be experimentally determined by actually driving the motor 104a. In addition, the distance difference between the predetermined second position N2 and the target stop position TP is expressed as D2. Regarding D2, the advance angle is rapidly changed from θ1 to θ2, and then the advance angle is changed to θ3 at a position satisfying N2-N1≦D1 to perform driving, and the rotation speed of the motor 104a falls within the self-starting region. It can be experimentally determined as the distance to.

According to the present embodiment, the rotor can be stopped at the target position accurately in a shorter time without shifting from the feedback control to the open loop control during deceleration stop.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a graph showing the profile of the moving speed and the advance angle of the lens holder 101, and the settings of the horizontal axis and the vertical axis are the same as those in FIG. In the present embodiment, differences from the first embodiment will be described, and detailed description of the same items as in the first embodiment will be omitted. The method of omitting such description is the same in the embodiments described later.

In the present embodiment, when the lens holder 101 reaches the predetermined first position N1, the advance angle suddenly changes from θ1 to θ2. The advance angle θ2 at the time when the motor 104a starts deceleration is set to a negative value. Although the rotor magnet 118 continues to rotate in the normal direction, a rotational torque that causes the rotor magnet 118 to rotate in the reverse direction is generated from the stator group, so that it is possible to further enhance the deceleration effect as compared with the first embodiment.

The speed of the rotor when driven at the first advance angle θ1 is outside the self-starting region, and the advance angle rapidly changes from θ1 (positive value) to θ2 (negative value) at the first position N1, The advance angle becomes θ3 (positive value) at the second position N2. The speed of the rotor corresponding to the speed V2 at the time of driving with the advance angle θ3 is within the self-starting region of the motor. According to this embodiment, the lens holder 101 can be stopped in a shorter time than in the first embodiment.

[Third Embodiment]
Next, a third embodiment of the invention will be described with reference to FIG. FIG. 10 is a graph showing a situation in the motor drive device 100 in which the lens holder 101 decelerates from the speed V1 during steady driving and stops at the target stop position TP, and FIG. Is the same as. The moving speed, the advance angle, and the motor drive voltage E1 of the lens holder 101 are shown.

At the drive voltage E1 of the motor driver 113, the motor 104a rotates so that the lens holder 101 moves along the optical axis at the steady speed V1. At this time, the voltage is applied to the stator group at the advance angle θ1 that generates the positive rotation torque. When the lens holder 101 reaches the first position N1, the motor 104a starts decelerating by rapidly changing the advance angle from θ1 to θ2. The value of the advance angle θ2 is zero, and the phase relationship between the magnetic field generated by the stator group and the magnetic field of the rotor magnet 118 is in the state shown in FIG. The rotor magnet 118 is kept in a state where no rotational torque is generated, and the lens holder 101 continues to decelerate.

Braking force is generated in the lens holder 101 due to various loads, and the moving speed gradually decreases. If this state continues, the lens holder 101 naturally stops, but its stop position varies depending on load conditions (environmental temperature, humidity, posture, etc.) at each time. In order to stop the lens holder 101 at an accurate position, when the lens holder 101 that continues deceleration reaches the second position N2, the advance angle is changed from θ2 to θ3, and drive control before stop is performed.

The motor 104a is rotated by the rotation torque generated at the advance angle θ3, and the lens holder 101 ideally continues to move at a constant speed indicated by V2(Pf1). The speed V2 at this time is defined by the difference between the force due to various loads and the driving force generated by the motor 104a due to the advance angle θ3. Since the value of the advance angle θ3 is small, the rotational torque generated is small, and the speed V2 is greatly influenced and fluctuates as shown by V2a and V2b in FIG. For example, depending on the position of the lens holder 101, various loads may decrease, the speed may increase, and the self-starting region (see V3) may be exceeded (see V2a). On the other hand, when various loads increase and the speed significantly decreases, the rotating torque may yield to the sliding load and stop before the target stop position TP (see V2b).

Therefore, in the present embodiment, the CPU 112 performs speed control that gradually decreases the speed toward the target stop position TP as shown by the profile V2 (Pf2) in FIG. 10, and more accurately stops at the target stop position TP. It can be performed. That is, the speed V2 (Pf1) before the stop has a constant value, whereas the speed V2 (Pf2) gradually decreases toward the target stop position TP and gradually changes to the predetermined speed value.

[Fourth Embodiment]
FIG. 11 is a graph showing a situation in which the lens holder 101 decelerates from the speed V1 during steady driving and stops at the target stop position TP in the motor drive device 100 of the fourth embodiment. The settings are the same as in FIG. The moving speed, the advance angle, and the drive voltage E1 of the lens holder 101 are shown.

When the lens holder 101 that continues deceleration reaches the second position N2, the advance angle is changed from θ2 to θ3, and drive control before stop is performed. As described above, the speed V2 varies due to various load factors (see V2a and V2b).

In the present embodiment, the CPU 112 variably controls the drive voltage E1 (see the drive voltage E1a). That is, since the feedback control is performed so that the speed V2 (Pf1) becomes constant, the motor speed corresponding to the moving speed of the lens holder 101 does not exceed the self-starting region (see V3), and the target stop position TP is set. The rotor will not stop just before.
According to the present embodiment, the speed variation of the rotor can be suppressed by the variable control of the drive voltage E1 before the stop.

[Fifth Embodiment]
FIG. 12 is a graph showing a situation where the lens holder 101 decelerates from the speed V1 during steady driving and stops at the target stop position TP in the motor drive device 100 of the fifth embodiment. The setting is the same as in FIG. The moving speed, the advance angle, and the drive voltage E1 of the lens holder 101 are shown.

In the present embodiment, the CPU 112 performs variable control of the advance angle θ3 (see advance angle θ3a) as a measure against variations (see V2a and V2b) that occur in the speed V2 due to various load factors. That is, by performing feedback control of the advance angle θ3 so that the speed V2 (Pf1) is constant, the motor speed corresponding to the moving speed of the lens holder 101 does not exceed the self-starting region (see V3), and The rotor does not stop before the target stop position TP.
According to this embodiment, the speed variation of the rotor can be suppressed by the variable control of the advance angle θ3 before the stop.

[Sixth Embodiment]
FIG. 13 is a graph showing a situation where the lens holder 101 decelerates from the speed V1 during steady driving and stops at the target stop position TP in the motor drive device 100 of the sixth embodiment. The settings are the same as in FIG. The moving speed, the advance angle, and the drive voltage E1 of the lens holder 101 are shown.

In the present embodiment, the CPU 112 performs variable control of the advance angle θ3 and the drive voltage E1 as a countermeasure against variations (see V2a and V2b) that occur in the speed V2 due to various load factors (see drive voltage E1a and advance angle θ3a). ). That is, feedback control of the advance angle θ3 and the drive voltage E1 is performed so that the speed V2 (Pf1) is constant. Therefore, the motor speed corresponding to the moving speed of the lens holder 101 does not exceed the self-starting region (see V3), and the rotor does not stop before the target stop position TP.
According to the present embodiment, the speed variation of the rotor can be suppressed by the variable control of the drive voltage E1 and the advance angle θ3 before the stop.

In the fourth to sixth embodiments, the motor drive is continued so that the speed V2 (Pf1) is constant, and when the lens holder 101 reaches the target stop position TP, holding energization for maintaining the energization phase state at that time is performed. Drive stops. At this time, since the rotation speed of the motor 104a is within the self-starting region, even if the holding current is suddenly changed, step-out does not occur and the lens holder 101 can be accurately stopped at the target position. ..

[Other Embodiments]
The present invention is not limited to the embodiments described above, and various modifications and changes can be made without departing from the gist of the present invention. For example, although the advance angle is changed from θ1 to θ2 and further to θ3 in the above-described embodiment, it is possible to control the advance angle to be further changed stepwise or continuously between θ2 and θ3. Further, it is possible to realize simpler control by setting the advance angle θ2 and the advance angle θ3 at the time of deceleration to the same value.

100 Motor Drive Device 101 Lens Holder 102, 103 Guide Bar 104a Motor 104e ENC Magnet 104f Hall Element Package 111 Drive Waveform Generation Circuit 112 CPU
114-117 stator 118 rotor magnet

Claims (12)

A first control for driving the motor by open loop control according to a driving waveform of a preset frequency, and a detection signal by a detection means for detecting the position of the rotor of the motor are acquired to obtain the stator and the rotor of the motor. And a control means for performing a second control for driving the motor by feedback control by determining an advance angle representing a phase relationship of
In the second control, the control means stops the rotor at the target stop position when the rotor reaches a first position predetermined with respect to the target stop position. The deceleration control is performed with a second advance angle smaller than the first advance angle during steady drive, and the third speed control is performed when the rotor reaches a second position predetermined with respect to the target stop position. The motor drive device is characterized in that the rotor is driven at an advance angle of, and the speed of the rotor at the time of drive at the third advance angle is within a self-starting region when the motor is driven by the first control. When the second advance angle is represented by θ2 and the third advance angle is represented by θ3,
The motor drive device according to claim 1, wherein the control unit sets an advance angle that satisfies a condition of θ2≦θ3. When the rotation of the rotor when the first advance angle is set is a positive rotation,
The motor drive device according to claim 1 or 2, wherein the control means sets an advance angle for generating a driving force in a reverse rotation direction as the second advance angle. The first advance angle and the second advance angle are denoted by θ1 and θ2, respectively, and the first position and the second position are denoted by N1 and N2, respectively, and the control means sets the advance angle by θ1. When the distance from the stop of the rotor when changing from θ2 to θ2 is expressed as D1,
The said 1st and 2nd position satisfy|fills the relationship of N2-N1<=D1, The motor drive device of any one of Claim 1 to 3 characterized by the above-mentioned. When the third advance angle is expressed as θ3 and the difference between N2 and the target stop position is expressed as D2,
After the control means changes the advance angle from θ1 to θ2, the D2 performs drive control by changing the advance angle to θ3 at N2 until the speed of the rotor falls within the self-starting region. It is distance. The motor drive device according to claim 4 characterized by things. The motor drive device according to claim 1, wherein the speed of the rotor when driven at the first advance angle is outside the self-starting region. 7. The control means performs control to carry out holding energization and stop when the rotor reaches the target stop position after the drive by the third advance angle. The motor drive device according to item 1. When decelerating the rotor to stop at the target stop position, the control means controls the drive at the third advance angle and controls the drive voltage to the motor to control the fluctuation of the speed of the rotor. The motor drive device according to any one of claims 1 to 7, wherein control is performed to suppress the motor drive. The control means performs control for suppressing fluctuations in the speed of the rotor by controlling the third advance angle when decelerating the rotor to stop at the target stop position. 9. The motor drive device according to any one of 1 to 8. When decelerating the rotor and stopping it at the target stop position, the control means drives the rotor at the third advance angle to control the speed of the rotor to be constant within the self-starting region, or to stop the target. The motor drive device according to any one of claims 1 to 9, wherein control for gradually decelerating the rotor toward a position is performed. The motor drive device according to any one of claims 1 to 10 is provided,
An imaging apparatus, wherein an optical member is moved by the motor. A first control step of driving the motor in open loop control according to a drive waveform of a preset frequency;
A second control step in which a detection signal is obtained from detection means for detecting the position of the rotor of the motor, a lead angle representing the phase relationship between the stator of the motor and the rotor is determined, and the motor is driven by feedback control. And have
In the second control step, when the rotor is stopped at the target stop position,
When the rotor reaches a predetermined first position with respect to the target stop position, deceleration control is performed with a second advance angle that is smaller than the first advance angle during steady drive of the rotor. I,
Further, when the rotor reaches a predetermined second position with respect to the target stop position, driving is performed with a third advance angle,
The method for controlling a motor drive device, wherein the speed of the rotor when driven by the third advance angle is within a self-starting region when the motor is driven by the first control step.

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