JP2010246252A - Motor drive and optical controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive for achieving high-speed driving and suppressing deterioration in accuracy at the time of driving a plurality of motors. <P>SOLUTION: The motor drive is provided with: a first motor 108 having a first rotor rotated by switching supply of power to a first coil, a first driver 107 driving the first motor 108, a second motor 111 having a second rotor rotated by switching supply of power to a second coil, a second driver 109 switching conduction to the second coil of the second motor 111 at predetermined time intervals, a third driver 110 switching conduction to the second coil of the second motor 111 in accordance with output of a position sensor 112, and a control circuit 105 controlling a system so that the second motor 111 is driven not by the third driver 110 but the second driver 109 at the time of driving the first motor 108 and driving the second motor 111. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor driving device capable of driving a plurality of motors.

  In addition to the features of small size, low cost, and high torque, the step motor can be rotated at a predetermined angle by switching energization to the coil, so that the position control can be easily performed without a position sensor. Have. For this reason, open loop control is generally performed to switch the energization state of the coil according to a predetermined time interval.

  However, there is a problem that the rotor becomes unable to respond to switching of energization to the coil under high-speed driving or high-load conditions, so that step-out is likely to occur. Therefore, a motor corresponding to high-speed driving has been proposed in which a position sensor for detecting the rotor position is added and feedback control is performed to switch the energization state of the coil in accordance with the output of the position sensor.

  Patent Document 1 proposes a step motor control device that controls a step motor by switching between a first operation mode and a second operation mode. The first operation mode is so-called open loop control in which the command value given to the drive unit is changed based on the timing generated by the control unit itself. The second operation mode is so-called feedback control in which the command value given to the drive unit is changed based on the timing according to the detection signal of the position detection unit.

  In open loop control, high-precision positioning is possible by microstep drive, while high-speed drive is possible in feedback control. For this reason, according to Patent Document 1, it is possible to provide a step motor control device that simultaneously realizes both high-precision positioning and high-speed transfer.

JP-A-10-150798

  However, when a plurality of the aforementioned motors are driven simultaneously, there are the following problems.

  In the feedback control, the energization state of the coil is switched according to the rotor position. Therefore, when the rotational load and torque of the rotor are constant, the rotational speed of the rotor is constant and the switching cycle of energization to the coil is constant. However, in practice, the rotational load and torque of the rotor differ depending on the motor depending on various conditions such as transmission mechanism, assembly variation, current fluctuation, or environment. Therefore, when a plurality of motors are driven simultaneously, the switching periods of energization to the coils of the motors are also different from each other. Therefore, in feedback control, it is difficult to drive a plurality of motors synchronously.

  On the other hand, in the open loop control, the energization state of the coil is switched according to a predetermined time interval. Therefore, it is possible to keep the switching cycle of energization to the coil constant regardless of the rotational load and torque of the rotor. Therefore, in open loop control, it is easy to drive a plurality of motors synchronously. However, as described above, in the open loop control, there is a problem that the rotor cannot respond to switching of energization to the coil under high speed driving or high load conditions, and the step out is likely to occur.

  The present invention provides a motor drive device that can be driven at high speed and suppresses deterioration in accuracy when driving a plurality of motors.

  A motor driving device according to one aspect of the present invention is a motor driving device that drives a first motor and a second motor, the first driving means that drives the first motor, and the second motor at a predetermined time interval. According to the output of the second drive means for driving the second motor by switching the energization state of the coil and the detection means for detecting the rotor position of the second motor, the energization state of the coil of the second motor is changed. When driving the third motor to be switched and the first motor while driving the second motor, control is performed so that the second motor is driven by the second driving means instead of the third driving means. Control means.

  An optical control apparatus according to another aspect of the present invention includes a first motor that drives the first optical system, a first drive unit that drives the first motor, a second motor that drives the second optical system, and a predetermined motor. Second driving means for switching the energization state of the coil of the second motor at a time interval of, a detection means for detecting a rotor position of the second motor, and a coil of the second motor according to the output of the detection means When driving the first motor while driving the second motor, the second motor is driven not by the third driving means but by the second driving means. And control means for controlling so as to.

  Other objects and features of the present invention are illustrated in the following examples.

  ADVANTAGE OF THE INVENTION According to this invention, the motor drive device which can drive at high speed and suppresses a precision degradation at the time of a several motor drive can be provided.

1 is a configuration diagram of a camera in Embodiment 1. FIG. It is a block diagram of the 2nd motor and position sensor in Example 1. FIG. In Example 1, it is an axial sectional view which shows the phase relationship of a yoke, a position sensor, and a rotor. In Example 1, it is a graph which shows the relationship between a rotor position and a motor torque, and the relationship between a rotor position and the output of a position sensor. In Example 1, it is an axial sectional view which shows the operation | movement of FB drive. 4 is a graph illustrating a relationship between a zoom lens position and a focus lens position in Example 1. In Example 1, it is explanatory drawing which shows the locus | trajectory information according to the to-be-photographed object distance memorize | stored in the control circuit. 3 is a flowchart illustrating a lens driving process of a control circuit in Embodiment 1. 10 is a flowchart illustrating a lens driving process of a control circuit in Embodiment 2. 10 is a flowchart illustrating lens driving processing of a control circuit in Embodiment 3. FIG. 10 is a configuration diagram of a camera in Embodiment 4.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same members are denoted by the same reference numerals, and redundant description is omitted.

  First, the camera (optical control apparatus) in Embodiment 1 of the present invention will be described. FIG. 1 is a configuration diagram of a camera 100 in the present embodiment. In FIG. 1, reference numeral 101 denotes a zoom lens (first optical system) that performs a zoom operation. The zoom lens 101 is driven by the first motor 108 and changes the magnification of the image on the imaging surface of the imaging element 103. A focus lens (second optical system) 102 performs a focus adjustment operation. The focus lens 102 is driven by the second motor 111 to change the focus state of the image on the imaging surface of the imaging element 103. Further, during the zoom operation of the zoom lens 101, the change in the focus state of the image on the imaging surface of the image sensor 103 is corrected. The correction of the focus state during the zoom operation will be described later.

  Reference numeral 103 denotes an image sensor, which is composed of a photoelectric conversion element such as a CCD or a CMOS sensor. The image sensor 103 converts external light incident through the zoom lens 101 and the focus lens 102 into an electrical signal and outputs the electrical signal. Reference numeral 104 denotes a signal processing circuit. The signal processing circuit 104 processes the electrical signal output from the image sensor 103 and outputs it as a video signal. More specifically, the signal processing circuit 104 performs gain adjustment, gamma processing, and the like on the analog electric signal output from the image sensor 103, and then outputs it as a digital video signal such as RGB image data.

  Reference numeral 105 denotes a control circuit (control means). The control circuit 105 processes the digital video signal output from the signal processing circuit 104 and outputs recording data to the memory 106. Further, the control circuit 105 outputs a zoom lens driving signal to the first driver 107 in accordance with the zoom command signal output from the zoom switch 113 and controls the first motor 108. In addition, a focus lens drive signal is output to the second driver 109 or the third driver 110 to control the second motor 111. Detailed operation of the control circuit 105 will be described later. Reference numeral 106 denotes a memory. The memory 106 records recording data output from the control circuit 105. In this embodiment, the type of the memory 106 is not limited, and various memories such as a memory card, a camera built-in memory, a tape, or a disk can be used as the memory 106.

  Reference numeral 107 denotes a first driver (first driving means). The first driver 107 drives the first motor 108 according to the drive signal output from the control circuit 105. The first driver 107 is configured by a normal step motor driver. Reference numeral 108 denotes a first motor. The first motor 108 is driven by the first driver 107 and drives the zoom lens 101. The first motor 108 is configured by a normal step motor.

  Reference numeral 109 denotes a second driver (second driving means). The second driver 109 drives the second motor 111 by open loop energization switching drive (OP drive) according to the drive signal output from the control circuit 105. Details of the OP drive will be described later. Reference numeral 110 denotes a third driver (third driving means). The third driver 110 drives the second motor 111 by feedback energization switching drive (FB drive) in accordance with the drive signal output from the control circuit 105 and the detection signal of the position sensor 112. Details of the FB drive will be described later. Reference numeral 111 denotes a second motor. The second motor 111 is driven by the second driver 109 or the third driver 110 and drives the focus lens 102. The configuration of the second motor 111 will be described later. Reference numeral 112 denotes a position sensor (detection means). The position sensor 112 detects the rotor position of the second motor 111 and outputs a detection signal. Reference numeral 113 denotes a zoom switch. The zoom switch 113 outputs a zoom command signal when operated by a user.

  The camera 100 in the present embodiment is configured by the above constituent elements. In addition, a motor driving device that drives the first motor 108 and the second motor 111 by the control circuit 105, the first motor 108, the second motor 111, the first driver 107, the second driver 109, and the third driver 110 is provided. Composed.

  In this embodiment, the second driver 109 and the third driver 110 are separately provided so that the OP driving or the FB driving can be switched. However, the second driver 109 and the third driver 110 can be switched to a single driver. It is possible to have both functions. In this case, one driver can be switched between OP driving and FB driving. In this embodiment, the object driven by each motor is a zoom lens and a focus lens. However, this invention does not limit the object driven by each motor. For example, it may be another object that needs to be driven in synchronization, such as a zoom lens and a finder zoom lens, a focus lens, and a shake correction lens.

  Next, the configuration of the second motor 111 in the present embodiment will be described. FIG. 2 is a configuration diagram of the second motor 111 and the position sensor 112 in the present embodiment. For the sake of explanation, some parts are shown broken. The structure of this motor is the same as that proposed by the present applicant as Japanese Patent Application Laid-Open No. 09-331666.

  The second motor 111 includes a rotor 202 having a magnet 201, a coil 203, a coil 204, a yoke 205, a yoke 206, a first position sensor 207, and a second position sensor 208. Among these, the coil 203, the coil 204, the yoke 205, the yoke 206, the first position sensor 207, and the second position sensor 208 constitute a stator.

  The magnet 201 is a cylindrical permanent magnet whose outer periphery is multipolarly magnetized. The magnet 201 has a magnetization pattern in which the strength of the magnetic force in the radial direction changes in a sine wave shape with respect to the angular position. The rotor 202 is rotatably supported with respect to the stator and is fixed integrally with the magnet 201.

  The yoke 205 has a plurality of magnetic pole teeth that are excited by the coil 203. The torque applied to the rotor 202 can be changed by switching the poles to be excited. The yoke 206 has a plurality of magnetic pole teeth that are excited by the coil 204. The torque applied to the rotor 202 can be changed by switching the poles to be excited.

  The first position sensor 207 and the second position sensor 208 are Hall elements that detect the magnetic flux of the magnet 201 and output a detection signal. These sensors correspond to the position sensor 112 in FIG. In this embodiment, the magnetic flux of the rotor magnet is detected by a Hall element. However, the present invention is not limited to the method of detecting the rotor position. For example, a detection magnet that is displaced with the rotation of the rotor may be arranged and detected, or the light shielding plate and the pattern surface may be read by an optical sensor. Further, the position sensor may be fixed integrally with the motor, or may be fixed to a member different from the motor.

  Next, open loop energization switching drive (OP drive) will be described. The second motor 111 can be OP driven by the second driver 109. The OP drive is the same as the open loop control of a normal stepping motor, and is a driving method that switches the energization state of the motor coil in accordance with a predetermined time interval. That is, the second driver 109 can rotate the rotor 202 at a desired speed by sequentially switching the energization of the coil 203 and the coil 204 according to the input drive pulse interval (drive frequency) and the rotation direction. (Speed control). Further, the second driver 109 can rotate the rotor 202 by a desired angle in accordance with the input drive pulse number (position control).

  In OP driving, the energization state of the coil is switched according to a predetermined time interval (drive pulse interval). The switching timing of energization to the coil does not depend on the rotational load of the rotor or the torque generated by the motor. For this reason, a plurality of motors can be easily driven synchronously.

  However, if the driving speed is increased (the driving pulse interval is shortened), the rotor cannot respond to switching of energization to the coil, and the possibility of causing a step-out increases. For this reason, it is necessary to add a lower limit to the drive pulse interval, and high-speed driving is limited.

  In FIG. 1, a first driver 107 that performs OP driving drives the first motor 108 by switching the energization state of the coil of the first motor 108 at a predetermined time interval. Similarly, the second driver 109 that performs OP driving drives the second motor 111 by switching the energization state of the coil of the second motor 111 at predetermined time intervals.

  Next, feedback energization switching drive (FB drive) will be described. The second motor 111 can perform FB driving using the third driver 110. The FB drive is the same as the feedback control of the brushless motor, and is a driving method that switches the energization state to the motor coil in accordance with the output of the position sensor. That is, the third driver 110 sequentially switches the energization of the coil 203 and the coil 204 in accordance with the input drive pulse number and rotation direction and the detection signal output from the position sensor 112. In this way, the third driver 110 can rotate the rotor 202 by a desired angle (position control). Further, the third driver 110 can rotate the rotor 202 with a desired torque by controlling the current flowing through the coil 203 and the coil 204 (current control).

  In the FB drive, the energization state of the coil is switched according to the output of the position sensor. The energization switching of the coil is performed according to the position of the rotor. For this reason, the occurrence of step-out due to the response delay of the rotor can be reduced, and high-speed driving is possible. However, the coil energization switching timing varies depending on the rotational load of the rotor and the torque generated by the motor. For this reason, in the case of FB drive, it is difficult to drive a plurality of motors synchronously.

  In FIG. 1, the third driver 110 that performs the FB drive switches the energization state of the coil of the second motor 111 according to the output of the position sensor 112 (detection means) that detects the rotor position of the second motor 111.

  Next, the phase relationship between the yoke and the position sensor in the second motor 111 will be described. FIG. 3 is an axial sectional view showing the phase relationship among the yoke, the position sensor, and the rotor in this embodiment. In the figure, the clockwise direction is the positive direction. 205a to d are magnetic pole teeth of the yoke 205, and 206a to d are magnetic pole teeth of the yoke 206. In this embodiment, the number of poles of the magnet is 8 and the magnetization angle P is 45 °. With respect to the yoke 205, the phase P / 2 of the yoke 206 is −22.5 °, the phase β1 of the first position sensor is + 22.5 °, and the phase β2 of the second position sensor is −45 °. .

In the following description, the operation of the motor will be described using the electrical angle. The electrical angle represents one period of magnet magnetic force as 360 °. When the number of poles of the rotor is M and the actual angle is θ ₀ , the electrical angle θ can be expressed by the following equation.

θ = θ ₀ × M / 2 (Formula 1-1)
The phase difference between the yoke 205 and the yoke 206, the phase difference between the first position sensor 207 and the second position sensor 208, and the phase difference between the yoke 205 and the first position sensor 207 are all 90 degrees in electrical angle. In FIG. 3, the magnetic pole tooth center of the yoke 205 and the north pole center of the magnet 201 are opposed to each other. This state is the initial state of the rotor and the electrical angle is 0 °.

  Next, the relationship between the rotor position and motor torque in the second motor 111 and the relationship between the rotor position and the output of each signal will be described. FIG. 4 is a graph showing the relationship between the rotor position and the motor torque and the relationship between the rotor position and the output of the position sensor in this embodiment.

  FIG. 4A is a graph showing the relationship between the rotation angle of the rotor and the motor torque. The horizontal axis indicates the electrical angle, and the vertical axis indicates the motor torque. The motor torque is positive when the rotor rotates clockwise. When a positive current flows through the coil 203, the yoke 205 is magnetized to the north pole, and an electromagnetic force is generated between the magnet 201 and the magnetic pole. Further, when a positive current is passed through the coil 204, the yoke 206 is magnetized to the north pole, and an electromagnetic force is generated between the magnetic pole of the magnet 201.

  When the two electromagnetic forces are combined, a substantially sinusoidal torque is obtained as the rotor 202 rotates (FIG. 4 (1): torque curve A + B +). Similarly, a substantially sinusoidal torque is also obtained in other energized states (FIG. 4 (1): torque curves A + B−, AB−, AB +). Further, the yoke 205 is arranged with a phase of 90 ° in electrical angle with respect to the yoke 206. For this reason, the four torques have a phase difference of 90 ° in electrical angle.

  FIG. 4B is a graph showing the relationship between the rotation angle of the rotor and the output of each signal, where the horizontal axis indicates the electrical angle and the vertical axis indicates the output of each signal. The strength of the magnet 201 in the radial direction is magnetized so as to be substantially sinusoidal with respect to the electrical angle. Therefore, a substantially sinusoidal signal is obtained from the first position sensor 207 (FIG. 4 (2): sensor signal A). In the present embodiment, the first position sensor 207 outputs a positive value when facing the north pole of the magnet 201.

  The second position sensor 208 is arranged with a phase of 90 ° in electrical angle with respect to the first position sensor 207. Therefore, a substantially cosine wave signal is obtained from the second position sensor 208 (FIG. 4 (2): sensor signal B). In the present embodiment, the polarity of the second position sensor 208 is reversed with respect to the first position sensor 207. For this reason, the second position sensor 208 outputs a positive value when facing the south pole of the magnet 201.

  Next, energization switching in the FB drive will be described. In FIG. 4B, the binarized signal A and the binarized signal B are signals obtained by binarizing the sensor signal A and the sensor signal B using a comparator or the like, respectively.

  In the FB drive, energization of the coil 203 is switched based on the binarized signal A, and energization of the coil 204 is switched based on the binarized signal B. That is, when the binarized signal A indicates a positive value, a current in the positive direction is supplied to the coil 203, and when the binarized signal A indicates a negative value, a current in the reverse direction is supplied to the coil 203. When the binarized signal B indicates a positive value, the coil 204 is energized in the positive direction, and when the binarized signal B indicates a negative value, the coil 204 is energized in the reverse direction.

  FIG. 5 is an axial sectional view showing the operation of the FB drive in this embodiment. FIG. 5A shows a state in which the rotor is rotated 135 ° in electrical angle. Each advance angle signal indicates a value represented by (a) in FIG. 4 (2), the binarized signal A indicates a positive value, and the binarized signal B indicates a negative value. Therefore, a positive current flows through the coil 203 and the yoke 205 is magnetized to the north pole. On the other hand, a reverse current flows through the coil 204 and the yoke 206 is magnetized to the south pole. At this time, the clockwise torque corresponding to the torque curve A + B− in FIG. 4 (1) works, and the rotor 202 receives the rotational force in the θ direction and rotates.

  FIG. 5B shows a state in which the rotor is rotated 180 degrees in electrical angle. The first position sensor 207 is located at the boundary between the N pole and the S pole of the magnet 201. Therefore, the binarized signal A is switched from a positive value to a negative value with the electrical angle of 180 ° as a boundary, and the energization direction of the coil 203 is switched from the positive direction to the reverse direction. This electrical angle coincides with the electrical angle at the intersection of the torque curve A + B− and the torque curve AB−.

  FIG. 5B 'shows a state in which the rotor is rotated 180 degrees in electrical angle and the energization direction of the coil 203 is switched. A reverse current flows through the coil 203 and the yoke 205 is magnetized to the south pole, and a reverse current flows through the coil 204 and the yoke 206 is magnetized to the south pole. At this time, a clockwise torque corresponding to the torque curve AB in FIG. 4A works, and the rotor 202 rotates in response to the rotational force in the θ direction.

  FIG. 5C shows a state where the rotor is rotated by 225 ° in electrical angle. Each advance angle signal indicates a value represented by (c) in FIG. 4B, and the binarized signal A and the binarized signal B both indicate negative values. Therefore, a negative current flows through the coil 203 and the yoke 205 is magnetized to the south pole, and a reverse current flows through the coil 204 and the yoke 206 is magnetized to the south pole. At this time, a clockwise torque corresponding to the torque curve AB in FIG. 4A is activated, and the rotor 202 receives the rotational force in the θ direction and rotates.

  FIG. 5D shows a state where the rotor is rotated by 270 ° in electrical angle. The second position sensor 208 is located at the boundary between the N pole and the S pole of the magnet 201. Therefore, the binarized signal B is switched from a negative value to a positive value with the electrical angle of 270 ° as a boundary, and the energization direction of the coil 204 is switched from the reverse direction to the positive direction. This electrical angle coincides with the electrical angle at the intersection of the torque curve AB- and the torque curve AB +.

  FIG. 5B ′ shows a state in which the rotor has rotated 270 ° in electrical angle and the energization direction of the coil 204 has been switched. A positive current flows through the coil 204 and the yoke 206 is magnetized to the south pole, and a reverse current flows through the coil 203 and the yoke 205 is magnetized to the south pole. At this time, the clockwise torque corresponding to the torque curve A-B + in FIG. 4 (1) works, and the rotor 202 receives the rotational force in the θ direction and rotates.

  By repeating the above operation, the rotor can be continuously rotated. Further, if the sign of the binarized signal A or the binarized signal B is inverted, reverse rotation is also possible.

  Next, the focus state correction will be described. FIG. 6 is a graph showing the relationship between the zoom lens position and the focus lens position in this embodiment. The horizontal axis represents the zoom lens position, and the vertical axis represents the focus lens position. The zoom lens position corresponds to the focal length. When the focus lens position for focusing on the imaging surface is plotted with respect to the focal length that changes as the zoom lens position changes, a locus as shown in FIG. 6 is shown for each subject distance.

  FIG. 7 is an explanatory diagram showing trajectory information corresponding to the subject distance stored in the control circuit 105 in this embodiment. The horizontal axis represents the zoom lens position, and the vertical axis represents the focus lens position. z0 to z6 are zoom lens position information stored in the control circuit 105. Since the zoom lens 101 is step-driven by the first motor 108, the zoom lens position information z0 to z6 has discrete values. The locus A is a focusing locus in the case of the subject distance La, and the locus B is a focusing locus in the case of the subject distance Lb.

  a0 to a6 are focus lens position information (trajectory information A) set along the locus A, and are stored in the control circuit 105 corresponding to the zoom lens positions z0 to z6. b0 to b6 are focus lens position information (trajectory information B) set along the trajectory B, and are stored in the control circuit 105 corresponding to the zoom lens positions z0 to z6. Since the focus lens 102 is step-driven by the second motor 111, the focus lens position information a0 to a6 and b0 to b6 are discrete values. In addition to this, a large amount of trajectory information is stored in the control circuit 105 in accordance with the subject distance. During the zoom operation, the locus information (focus lens position information) is selected according to the subject distance, and the focus lens 102 is driven, so that the zoom operation can be performed while maintaining the focus on the imaging surface. .

  Next, a lens driving process executed by the control circuit 105 will be described. FIG. 8 is a flowchart showing the lens driving process of the control circuit 105 in this embodiment. When the lens driving process is started (S101), the control circuit 105 determines whether or not a zoom command signal is output from the zoom switch 113 (S102). If it is determined that the zoom command signal is output, the control circuit 105 calculates the target position of the zoom lens 101 according to the zoom command signal (S103). Thereafter, the control circuit 105 calculates the target position of the focus lens 102 based on the trajectory information corresponding to the subject distance stored in the control circuit 105 (S104). The trajectory information will be described later.

  Next, the control circuit 105 calculates a zoom lens drive signal to be output to the first driver 107 from the calculated target position of the zoom lens 101. Further, the control circuit 105 calculates a focus lens drive signal to be output to the second driver 109 or the third driver 110 from the calculated target position of the focus lens 102 (S105). Subsequently, the control circuit 105 sets the focus lens drive signal to be output to the second driver 109 (S106). Further, the control circuit 105 outputs the calculated drive signals to the drivers, and synchronously drives the zoom lens 101 and the focus lens 102 (S107). As described above, the control circuit 105 drives the second motor 111 with the second driver 109 instead of the third driver 110 when driving the first motor 108 and driving the second motor 111 (for example, synchronous driving). Control to drive. Thereafter, the control circuit 105 ends the lens driving process (S112).

  On the other hand, if it is determined in step S102 that the zoom command signal is not output, the control circuit 105 calculates the target position of the focus lens 102 according to the subject distance (S108). Further, a focus lens drive signal to be output to the second driver 109 or the third driver 110 is calculated from the calculated target position of the focus lens 102 (S109). Subsequently, the control circuit 105 sets the focus lens drive signal to be output to the third driver 110 (S110). Further, the control circuit 105 outputs the calculated focus lens drive signal to the third driver 110 to drive only the focus lens 102 (S111). Then, the control circuit 105 ends the lens driving process (S112).

  In the lens driving process described above, when a zoom operation is instructed by the user, the zoom lens 101 and the focus lens 102 are synchronously driven in accordance with the trajectory information and the zoom command signal stored in the control circuit 105. Here, the synchronous drive means driving by matching the energization switching timing to the first motor 108 and the energization switching timing to the second motor 111. At this time, the second motor 111 that drives the focus lens 102 is driven by the second driver 109. That is, the second motor 111 is OP-driven by the second driver 109. As described above, the OP drive facilitates synchronous control of a plurality of motors.

  Consider a case where the current zoom lens position is z0, the current subject distance is La, and the current focus lens position is a0. At this time, the focus lens 102 is positioned on the locus A in FIG. 7, and the focus on the image plane is maintained. Then, it is determined that the zoom command is output in step S102 in FIG. 8, and the zoom lens target position corresponding to the zoom command is calculated as z6 in step S103. If the subject distance is La without changing, the target position of the focus lens 102 is calculated as a6 based on the trajectory information A in step S104. Thereafter, a drive signal is output based on the target position, and the second motor 111 is driven together with the first motor 108 (synchronous drive).

  When driving of the second motor 11 (synchronous driving) is started together with the driving of the first motor 108, the energization of the first motor 108 is sequentially switched, and the zoom lens position is z0 → z1 → z2 → z3 → z4. → z5 → z6. At the same time, the energization of the second motor 111 is sequentially switched, and the focus lens position changes from a0 → a1 → a2 → a3 → a4 → a5 → a6.

  At this time, the second motor 111 performs OP driving. For this reason, it becomes easy to make the switching timing of energization to the 2nd motor 11 coincide with the timing to the 1st motor 108, and synchronous driving of these motors becomes possible easily. Therefore, when the zoom lens position is z1 at time t1, the focus lens position is a1, and when the zoom lens position is z2 at time t2, the focus lens position is a2. Change. Therefore, during the synchronous driving of these motors, the zoom operation can be performed with the focusing accuracy secured without the focus lens position deviating from the locus A.

  Assuming that the second motor 111 performs FB driving during synchronous driving, the switching timing of energization to the coil varies depending on the rotational load of the rotor and the torque generated by the motor. For this reason, the focus lens position may deviate from the locus A during synchronous driving, and the zoom operation is performed in a state where the focusing accuracy is deteriorated.

  Also, according to the lens driving process described above, when the zoom operation is not instructed by the user, the target position of the focus lens 102 is calculated according to the subject distance, and only the focus lens 102 is driven. Is done. At this time, the second motor 111 that drives the focus lens 102 is driven by the third driver 110. That is, the second motor 111 is driven by FB driving. The FB drive can be driven at a higher speed than the OP drive. For this reason, when the zoom operation is not instructed by the user, a high-speed focusing operation is possible.

  In this embodiment, the first motor 108 is driven by the first driver 107 in the same manner as a normal step motor. However, the first motor 108 may be configured in the same manner as the second motor 111, and two drivers may be provided so that either OP driving or FB driving can be switched (selectable). At this time, when the second motor 111 is driven by OP driving, it is desirable that the first motor 108 is similarly driven by OP driving.

  The camera (motor drive device) in this embodiment includes a plurality of motors, and at least one of the motors is configured to be able to switch between open-loop drive (OP drive) and feedback drive (FB drive).

  According to this embodiment, it is possible to drive at a high speed during asynchronous driving of a plurality of motors, and to suppress deterioration in synchronization accuracy during synchronous driving of a plurality of motors. That is, a high-speed focusing operation is possible when the zoom is not operating, and a zooming operation can be performed while ensuring the focusing accuracy during the zoom operation.

  Next, a camera (optical control apparatus) in Embodiment 2 of the present invention will be described. Since the configuration of the camera, the configuration and driving method of the motor, and the correction of the focus state are the same as those in the first embodiment, their descriptions are omitted.

  A lens driving process performed by the control circuit 105 in this embodiment will be described. FIG. 9 is a flowchart showing the lens driving process of the control circuit 105 in this embodiment. When the lens driving process is started (S201), the control circuit 105 determines whether or not a zoom command signal is output from the zoom switch 113 (S202). When determining that the zoom command signal is output, the control circuit 105 calculates the target position of the zoom lens 101 according to the zoom command signal (S203). Next, the control circuit 105 calculates the target position of the focus lens 102 based on the trajectory information corresponding to the subject distance stored in the control circuit 105 (S204).

  Thereafter, the control circuit 105 calculates a zoom lens drive signal to be output to the first driver 107 from the target position of the zoom lens 101 calculated in step S203. Further, the control circuit 105 calculates a focus lens drive signal to be output to the second driver 109 or the third driver 110 from the target position of the focus lens 102 calculated in step S204 (S205).

  Next, the control circuit 105 determines whether or not the camera 100 is currently photographing (S206). Here, “being photographed” refers to a state (recording mode) in which recording data obtained by processing the digital video signal output from the signal processing circuit 104 is output and the memory 106 records the recording data. As described above, the control circuit 105 functions as a selection unit that selects one of a recording mode for recording an image obtained from the zoom lens 101 and the focus lens 102 and a non-recording mode for not recording the image. .

  When determining that the camera 100 is photographing, the control circuit 105 outputs a focus lens drive signal to the second driver 109 (S207). On the other hand, if the control circuit 105 determines that the camera 100 is not shooting, the control circuit 105 outputs a focus lens drive signal to the third driver 110 (S208). Subsequently, the control circuit 105 outputs the calculated drive signals to the drivers, and drives (synchronously drives) the focus lens 102 together with the zoom lens 101 (S209). In this way, the control circuit 105 drives the second motor 111 with the second driver 109 when both the first motor 108 and the second motor 111 are driven (synchronous driving) and the recording mode is selected. Control to do. Thereafter, the control circuit 105 ends the lens driving process (S214).

  On the other hand, when it is determined in step S202 that the zoom command signal is not output, the control circuit 105 calculates the target position of the focus lens 102 according to the subject distance (S210). Thereafter, the control circuit 105 calculates a focus lens drive signal to be output to the second driver 109 or the third driver 110 from the target position of the focus lens 102 calculated in step S210 (S211).

  Thereafter, the control circuit 105 sets the focus lens drive signal to be output to the third driver 110 (S212). Subsequently, the control circuit 105 outputs the calculated focus lens drive signal to the third driver 110 to drive only the focus lens 102 (S213). Then, the control circuit 105 ends the lens driving process (S214).

  According to the lens driving process described above, when the zoom operation is instructed by the user, the zoom lens and the focus lens are synchronously driven in accordance with the trajectory information and the zoom command signal stored in the control circuit. Synchronous driving is to drive by matching the switching timing of energization to the first motor and the switching timing of energization to the second motor.

  Further, in this embodiment, when the camera is shooting, the second motor is driven by OP driving, and when the camera is not shooting, the second motor is driven by FB driving. As described in the first embodiment, the second motor is driven by OP driving during the synchronous driving of a plurality of motors, so that the zoom operation can be performed while ensuring the focusing accuracy. Further, by driving the second motor by the FB drive, a high-speed focusing operation can be performed as compared with the OP drive.

  Further, according to the lens driving process described above, when the zoom operation is not instructed by the user, the focusing operation is performed by calculating the target position of the focus lens according to the subject distance and driving only the focus lens. Is called. At this time, FB driving is performed on the second motor that drives the focus lens. Since the FB drive can be driven at a higher speed than the OP drive, according to this embodiment, a high-speed focusing operation is possible.

  According to the camera of the present embodiment, when simultaneously driving a plurality of motors capable of open-loop driving and feedback driving, high-speed driving at the time of asynchronous driving is realized and deterioration in synchronization accuracy at the time of synchronous driving is suppressed. Is possible.

  That is, a high-speed focusing operation is possible when the zoom is not operating or when the camera is not photographing when the zooming operation is performed. Further, when the zoom operation is being performed and the camera is shooting, the zoom operation can be performed while ensuring the focusing accuracy. For this reason, it is possible to record an image with high focusing accuracy.

  Next, a camera (optical control apparatus) in Embodiment 3 of the present invention will be described. Since the configuration of the camera, the configuration and driving method of the motor, and the correction of the focus state are the same as those in the first embodiment, their descriptions are omitted.

  The camera of this embodiment has a lens barrel that is retracted (collapse driven) by at least one of the first motor 108 and the second motor 111. The retracting operation is to drive one or both of the first motor 108 and the second motor 111 to move at least one of the zoom lens 101 and the focus lens 102 to a predetermined position, thereby making the outer size of the camera variable. is there. For example, when the camera is turned off, both the zoom lens 101 and the focus lens 102 are retracted to the end on the image sensor 103 side. By doing so, the length of the optical system in the optical axis direction can be shortened, which contributes to downsizing of the camera when the power is turned off. Further, when the camera is turned on, both the retracted zoom lens 101 and focus lens 102 are restored, so that the photographing function at the time of turning on the power is not hindered. In this embodiment, the retracting / returning operation of these lenses is referred to as a retracting operation (collapse driving).

  Next, lens driving processing by the control circuit in the present embodiment will be described. FIG. 10 is a flowchart illustrating the lens driving process of the control circuit 105 according to the third embodiment. When the lens driving process is started (S301), the control circuit 105 determines whether or not a collapsing operation is performed (S302). When it is determined that the retracting operation is being performed, the control circuit 105 calculates the target position of the zoom lens 101 according to the retracted position information (S303).

  Next, the control circuit 105 calculates the target position of the focus lens 102 according to the retracted position information (S304). Subsequently, the control circuit 105 calculates a zoom lens drive signal to be output to the first driver 107 from the target position of the zoom lens 101 calculated in step S303. Further, the control circuit 105 calculates a focus lens drive signal to be output to the second driver 109 or the third driver 110 from the target position of the focus lens 102 calculated in step S304 (S305). Next, the control circuit 105 sets the focus lens drive signal to be output to the third driver 110 (S306). Thereafter, the control circuit 105 outputs the calculated drive signals to the drivers, and simultaneously drives the zoom lens 101 and the focus lens 102 (S307). Thus, the control circuit 105 ends the lens driving process (S313).

  On the other hand, when it is determined in step S302 that the collapsing operation is not performed, the control circuit 105 calculates the target position of the zoom lens 101 according to the zoom command signal (S308). Subsequently, the control circuit 105 calculates the target position of the focus lens 102 based on the trajectory information corresponding to the subject distance stored in the control circuit 105 (S309). Next, the control circuit 105 calculates a zoom lens drive signal to be output to the first driver 107 from the target position of the zoom lens 101 calculated in step S308. Further, the control circuit 105 calculates a focus lens drive signal to be output to the second driver 109 or the third driver 110 from the target position of the focus lens 102 calculated in step S309 (S310). Subsequently, the focus lens drive signal is set to be output to the second driver 109 (S311).

  Next, the control circuit 105 outputs the calculated drive signals to the drivers, and synchronously drives the zoom lens 101 and the focus lens 102 (S312). Thus, the control circuit 105 controls the second motor 111 with the second driver 109 when both the first motor 108 and the second motor 111 are driven (synchronized driving) and the lens barrel is not driven to be retracted. Control to drive. Thereafter, the control circuit 105 ends the lens driving process (S313).

  According to the lens driving process described above, when the retracting operation is not performed, the zoom lens 101 and the focus lens 102 are synchronously driven according to the trajectory information stored in the control circuit 105 and the zoom command signal. The synchronous drive is to drive the energization switching timing to the first motor 108 and the energization switching timing to the second motor 111 to coincide with each other.

  During the synchronous driving, the second motor 111 is driven by OP driving. As described in the first embodiment, the second motor 111 is driven by the OP drive during the synchronous drive, so that the zoom operation can be performed while maintaining the focusing accuracy. Further, since the second motor 111 is driven by the FB drive, a high-speed focusing operation can be performed as compared with the OP drive.

  Further, according to the lens driving process described above, when the retracting operation is performed, the target positions of the zoom lens 101 and the focus lens 102 are calculated according to the retracted position information, and these lenses are driven simultaneously. At this time, FB driving is performed on the second motor 111 that drives the focus lens 102. Since the FB drive can be driven at a higher speed than the OP drive, a high-speed collapsing operation is possible.

  According to the camera of this embodiment, when simultaneously driving a plurality of motors capable of open-loop driving and feedback driving, high-speed driving during asynchronous driving is possible, and deterioration in synchronization accuracy during synchronous driving is suppressed. It becomes possible. In other words, the retracting operation can be performed at a high speed, and the lens can be driven while the synchronization accuracy is ensured during the non-collapse operation.

  Next, a camera (optical control apparatus) according to Embodiment 4 of the present invention will be described. In the present embodiment, the configuration and driving method of the motor are the same as those in the first embodiment, and thus description thereof is omitted.

  FIG. 11 is a configuration diagram of the camera in the present embodiment. FIG. 11A is a top view of the camera, and FIG. 11B is a side view as seen from the viewing direction (b) in FIG. The camera in this embodiment has a so-called pan / tilt barrel. 301 is a pan operation motor. The pan operation motor 301 is configured to be able to drive the lens barrel 303 in the pan direction (horizontal direction) in FIG. 11A and can change the optical axis direction of the lens barrel 303. Reference numeral 302 denotes a tilt operation motor. The tilt operation motor 302 is configured to be able to drive the lens barrel 303 in the tilt direction (vertical direction) in FIG. 11B and can change the optical axis direction of the lens barrel 303.

  Both the pan operation motor 301 and the tilt operation motor 302 have the same configuration as the second motor 111 in the first embodiment, and can be driven by switching between OP driving and FB driving. Reference numeral 303 denotes a lens barrel. The lens barrel 303 converts incident light from the subject into a video signal.

  In this embodiment, when the pan operation motor 301 and the tilt operation motor 302 are driven synchronously, both the pan operation motor 301 and the tilt operation motor 302 are driven by switching to the OP drive. In OP driving, it is possible to perform driving without degrading synchronization accuracy by matching the switching timing of energization to the coil. For this reason, it is possible to reduce image shake due to deterioration of synchronization accuracy. When the pan operation motor 301 and the tilt operation motor 302 are driven separately or without being synchronized, the pan operation motor 301 and the tilt operation motor 302 are both switched to FB drive and driven. Since the FB drive can be driven at a higher speed than the OP drive, a high-speed pan operation or tilt operation can be performed.

  In the present embodiment, a so-called pan / tilt lens barrel has been described. However, in the present embodiment, the motor drive target is not limited to the pan / tilt lens barrel. For example, the configuration of this embodiment can also be applied to a shake correction apparatus that corrects image shake by driving the correction lens in the optical system in two different directions perpendicular to the optical axis. At this time, when synchronously driving the first motor that drives the correction lens in the first direction and the second motor that drives the correction lens in the second direction, both the first motor and the second motor are switched to OP driving. To drive. By such control, it is possible to suppress the deterioration of the correction accuracy accompanying the deterioration of the synchronization accuracy. Further, when these motors are driven separately or without being synchronized, both can be switched to the FB drive to drive the motor at high speed.

  The same applies to a stage drive device that drives a stage in two directions using two motors, for example. In that case, when synchronously driving the first motor that drives the stage in the first direction and the second motor that drives the stage in the second direction, both of these motors are driven by switching to OP driving. Therefore, it is possible to suppress accuracy degradation due to degradation of synchronization accuracy. Further, when these motors are driven separately or without being synchronized with each other, high-speed stage driving can be achieved by switching to FB driving.

  The same applies to the case of using three or more motors that can be driven by switching between OP driving and FB driving. For example, when at least two of the three motors are driven synchronously, it is possible to reduce the deterioration of the synchronization accuracy by switching the two synchronously driven motors to OP driving.

  According to the camera of the present embodiment, when simultaneously driving a plurality of motors capable of open-loop control and feedback control, high-speed driving at the time of asynchronous driving is realized and deterioration of synchronization accuracy at the time of synchronous driving is suppressed. Is possible.

  According to each of the embodiments described above, it is possible to provide a camera, a motor driving device, and a lens driving device that can be driven at high speed and suppress deterioration in accuracy during synchronous driving.

  The embodiment of the present invention has been specifically described above. However, the present invention is not limited to the matters described as the above-described embodiments, and can be appropriately changed without departing from the technical idea of the present invention.

100 Camera 105 Control Circuit 107 First Driver 108 First Motor 109 Second Driver 110 Third Driver 111 Second Motor 112 Position Sensor

Claims (7)

A motor driving device for driving a first motor and a second motor,
First driving means for driving the first motor;
Second driving means for driving the second motor by switching the energization state of the coil of the second motor at a predetermined time interval;
Third driving means for switching the energization state of the coil of the second motor according to the output of the detecting means for detecting the rotor position of the second motor;
Control means for controlling the second motor to be driven by the second driving means instead of the third driving means when driving the first motor and the second motor;
A motor drive device comprising: A first motor for driving the first optical system;
First driving means for driving the first motor;
A second motor for driving the second optical system;
Second driving means for switching the energization state of the coil of the second motor at a predetermined time interval;
Detecting means for detecting a rotor position of the second motor;
Third driving means for switching the energization state of the coil of the second motor according to the output of the detection means;
Control means for controlling the second motor to be driven by the second driving means instead of the third driving means when driving the first motor and the second motor;
An optical control device comprising: A selection means for selecting any one of a recording mode for recording an image obtained from the first optical system and the second optical system and a non-recording mode for not recording the image;
The control means drives the second motor by the second driving means when both the first motor and the second motor are driven and the selection means selects the recording mode. The optical control device according to claim 2, wherein A lens barrel that is retracted by at least one of the first motor and the second motor;
The control means controls the second motor to drive the second motor when both the first motor and the second motor are driven and the lens barrel is not driven to retract. The optical control device according to claim 3.   5. The optical control apparatus according to claim 2, wherein the first optical system is a zoom lens, and the second optical system is a focus lens. 6. 2. The motor driving apparatus according to claim 1, wherein the first driving unit drives the first motor by switching an energization state to a coil of the first motor at a predetermined time interval. 6. The optical control according to claim 2, wherein the first driving unit drives the first motor by switching an energization state of the coil of the first motor at a predetermined time interval. apparatus.