Driving device, optical device, control method for driving device, and program

Abstract

To provide a drive device that can improve the driving accuracy of the position of optical elements. [Solution] The drive device (200) includes a motor (201) that drives an optical element (101), a first detection unit (204) that detects the position of the motor, a second detection unit (205) that detects the position of the optical element, and a control unit (206) that performs first control to control the position of the motor by a first output value corresponding to the difference between a command position corresponding to user operation and the position of the motor. The control unit determines a correction amount for the first output value to reduce the difference when the amount of deviation between the position of the motor and the position of the optical element exceeds a first threshold.

Description

Technical Field

[0006]

[0001] The present invention relates to a drive device, an optical device, a control method for a drive device, and a program.

Background Art

[0002] Patent Document 1 discloses a drive control device that selectively uses lens position-based control for detecting and controlling the position of a lens and motor position-based control for detecting and controlling the position of a motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A drive device capable of enhancing the driving accuracy of the position of an optical element is desired.

Means for Solving the Problems

[0005] A drive device according to one aspect of the present invention includes a motor that drives an optical element, a first detection unit that detects the position of the motor, a second detection unit that detects the position of the optical element, and a control unit that performs first control for controlling the position of the motor by a first output value corresponding to a difference between a commanded position according to a user operation and the position of the motor. The control unit determines a correction value of the first output value so as to reduce the amount of deviation when the amount of deviation between the position of the motor and the position of the optical element exceeds a first threshold value.

Effects of the Invention

[0006] According to the present invention, it is possible to provide a drive device capable of enhancing the driving accuracy of the position of an optical element.

Brief Description of the Drawings

[0007] [Figure 1] This is a block diagram of the lens apparatus in each embodiment. [Figure 2] These are schematic diagrams showing the motor gear and lens gear states 1 and 2 in each embodiment. [Figure 3] This is a schematic diagram showing the state 3 of the motor gear and lens gear in each embodiment. [Figure 4] This is a schematic diagram illustrating the problem in Example 1. [Figure 5] This is a flowchart showing the deviation correction process in Example 1. [Figure 6] This is a schematic diagram illustrating the deviation correction in Example 1. [Figure 7] This is a schematic diagram illustrating the problems in Example 2. [Figure 8] This is a flowchart showing the offset correction process in Example 2. [Figure 9] This is a schematic diagram illustrating the offset correction in Example 2. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Examples]

[0009] First, with reference to Figure 1, the lens device 100 in Embodiment 1 of the present invention will be described. Figure 1 is a block diagram of the lens device 100. The lens device 100 is configured to include an imaging optical system including a zoom lens 101, a focus lens (not shown), and optical adjustment members such as an iris (aperture diaphragm), as well as means for operating the optical adjustment members. Hereinafter, the zoom lens 101 will be described as a movable optical member (optical element) that is driven, but the present invention is not limited thereto. It is similarly applicable to movable optical members such as focus lenses and irises that are driven via a power transmission mechanism with backlash.

[0010] The drive unit (drive device) 200 comprises a motor 201, a motor gear 202, a lens gear 203, a motor position detection unit (first detection unit) 204, a lens position detection unit (second detection unit) 205, and a lens control unit (control unit) 206.

[0011] The motor 201 is composed of, for example, a DC motor or a voice coil motor and drives the zoom lens 101. A motor gear 202 is connected to the motor 201, and the motor gear 202 engages with the lens gear 203. The lens gear 203 is connected to the zoom lens 101 via a power transmission unit (not shown), and the configuration allows the zoom lens 101 to be driven by the driving force of the motor 201.

[0012] Motor gear 202 and lens gear 203 are connected to motor position detection units 204 and 205, respectively, enabling detection of motor position Mposi and lens position Lposi. The motor position detection units 204 and 205 are, for example, potentiometers or encoders.

[0013] The lens control unit 206 receives the command position Ctlpos, the motor position Mposi detected by the motor position detection unit 204, and the lens position Lposi detected by the lens position detection unit 205 as inputs. The command position Ctlpos is a position signal that is updated at a constant period of, for example, about 4 msec, but is not limited to this. Based on the input command position Ctlpos and either the motor position Mposi or the lens position Lposi, the control output for motor driving is calculated.

[0014] The control output Mout (the first output value) in the motor position-based control (the first control) can be calculated by, for example, the following arithmetic expression (1). The motor position-based control is the control of the position of the motor 201 by an output value (the first output value) corresponding to the difference between the commanded position according to the user's operation and the position of the motor 201 (the motor position Mposi). Also, the control output Lout (the second output value) in the lens position-based control (the second control) can be calculated by the following arithmetic expression (2). The lens position-based control is the control of the position of the zoom lens 101 by an output value (the second output value) corresponding to the difference between the commanded position and the position of the zoom lens 101. Note that the arithmetic expressions are not limited to these.

[0015]

Number

[0016]

Number

[0017] In addition to being detected by the motor position detector 204, the motor position Mposi may be calculated based on the back electromotive force of the motor 201 generated in response to the rotation of the motor 201. The back electromotive force Vr can be calculated by the following arithmetic expression (3) from the motor current I detected by a motor current detector (not shown), the applied voltage Vm to the motor 201, and the circuit resistance R including the internal resistance of the motor 201. Since the back electromotive force Vr is proportional to the rotational speed of the motor, the motor speed can be obtained from the back electromotive force Vr, and the motor position Mposi can be calculated by integrating the motor speed.

[0018]

Number

[0019] Next, the movement of the POT12 gear and the MOT13 gear in this embodiment will be explained. Mechanically driven mechanisms generally have various types of play, and in this embodiment as well, there is play such as backlash between each gear.

[0020] Figures 2(a) and (b) are schematic diagrams showing the engagement state between the motor gear 202 and the lens gear 203. Each gear is assumed to rotate clockwise and counterclockwise on the plane of the paper, respectively. The explanation will focus on two adjacent teeth of the motor gear 202, indicated by A1 and A2, and two adjacent teeth of the lens gear 203, indicated by B1 and B2.

[0021] Figure 2(a) shows the normal state in which the motor gear 202 drives the lens gear 203 (movable optical element side) at a constant speed, and it is assumed that A1 of the motor gear 202 and B1 of the lens gear 203 are engaged. This state is referred to as "State 1".

[0022] Figure 2(b) shows that only the lens gear 203 accelerates rapidly from state 1, and the B1 of the lens gear 203 separates from the A1 of the motor gear 202. This state is referred to as "state 2". Furthermore, since this rapid acceleration is not intentionally commanded, the lens position Lposi precedes the commanded position Ctlpos. For example, when using the lens device 100 at an angle and performing zoom driving at a low speed, the operation may reach state 2 due to the self-weight of the zoom lens 101.

[0023] The challenges of performing lens position-based control in state 2 are explained below. In state 2, as described above, the lens position is ahead of the commanded position, so a control is activated to rapidly decelerate the zoom lens 101 in order to bring the lens position to match the commanded position. Consequently, the zoom lens 101 rapidly decelerates immediately after accelerating due to its own weight, resulting in large velocity fluctuations and an unnatural zoom operation in the image.

[0024] On the other hand, at the moment of rapid acceleration in state 2, the motor position does not precede the commanded position, but operates in the same way as in normal state 1. Therefore, when motor position-based control is applied, no control that would rapidly decelerate the lens position is activated, and the motor 201 is driven at a constant speed, just as before the rapid acceleration. Consequently, the velocity fluctuations when the lens falls under its own weight are reduced, and the unnatural appearance in the image can be eliminated.

[0025] While the effectiveness of motor position-based control has been described, since motor position-based control is a control method that matches the motor position to the commanded position, a discrepancy between the lens position and the commanded position may occur if there is backlash between the gears. In other words, a situation may arise where the lens position differs for the same commanded position, resulting in a problem of reduced driving accuracy (position repeatability) of the lens position.

[0026] The configuration of this embodiment for solving this problem will be described below. In this embodiment, in motor position base control, correction is performed so that the amount of discrepancy between the command position and the lens position is reduced.

[0027] In motor position-based control, after state 2, as shown in Figure 3, the motor gear 202's A1 and the lens gear 203's B2 become engaged, and this state is referred to as "state 3". Unlike the normal state in which the motor gear 202 drives the lens gear 203, state 3 is a state in which the rotation of the lens gear 203 is suppressed by the motor gear 202 while the system operates. In state 3, the lens position precedes the commanded position, and there is a discrepancy between the commanded position and the lens position. As long as the speed due to the self-weight fall of the zoom lens 101 exceeds the commanded speed (change in commanded position), the lens position will continue to change while maintaining the discrepancy between the commanded position and the lens position.

[0028] Next, referring to Figure 4, the relationship between the command position Ctlpos, motor position Mposi, and lens position Lposi in each of the three states (States 1 to 3) in motor position-based control will be explained. Figure 4 is a schematic diagram illustrating the problems of this embodiment. In Figure 4, the horizontal axis represents time, and the vertical axis in the lower part of Figure 4 represents position. In State 1, the motor position Mposi and the lens position Lposi coincide, and the motor position Mposi operates to follow the command position Ctlpos. In State 2, the gap between the lens position Lposi and the command position Ctlpos (motor position Mposi) widens as the zoom lens 101 falls under its own weight. State 3 shows the lens position Lposi transitioning while maintaining the gap that occurred in State 2.

[0029] The upper vertical axis in Figure 4 shows the control output Mout for motor position-based control in each state. In states 1 to 3, the deviation between the command position Ctlpos and the motor position Mposi remains constant, indicating that the control output Mout is constant.

[0030] Next, with reference to Figure 5, the discrepancy correction process (control method for the drive device) between the lens position Lposi and the command position Ctlpos (motor position Mposi) will be explained. Figure 5 is a flowchart of the discrepancy correction process in this embodiment.

[0031] First, in step S101, the lens control unit 206 calculates the normal control output Mout in motor position-based control. Next, in step S102, the lens control unit 206 calculates the difference diffLM between the lens position Lposi and the motor position Mposi. In motor position-based control, the motor position tracks the command position with a certain deviation corresponding to the drive speed and the torque value of the zoom lens 101. For this reason, during driving, it is necessary to correct the lens position Lposi to match the motor position Mposi. When stopping, the motor position Mposi and the command position Ctlpos converge to match, so the lens position Lposi also comes to match the command position Ctlpos.

[0032] Subsequently, in step S103, the lens control unit 206 determines whether or not the deviation amount diffLM exceeds a threshold value X (first threshold value). When the deviation amount diffLM exceeds the threshold value X, the lens control unit 206 performs deviation correction and thus transitions to step S104. On the other hand, when the deviation amount diffLM is less than or equal to the threshold value X, the lens control unit 206 does not perform deviation correction and transitions to step S106. The threshold value X is, for example, a value sufficiently smaller than a value required as the driving accuracy of the lens position with respect to the command position. Preferably, the threshold value X is a value less than or equal to the stop accuracy of the lens position.

[0033] In step S104, the lens control unit 206 calculates a deviation correction amount (correction value). The deviation correction amount can be calculated, for example, by multiplying the control output Mout by a constant gain corG (coefficient). The value of the constant gain corG is preferably in the range of, for example, 1 / 200 to 1 / 1000.

[0034] In the present embodiment, it is preferable that the deviation correction amount is in the range between a value obtained by multiplying the control output Mout by a first coefficient and a value obtained by multiplying the control output Mout by a second coefficient (Mout × first coefficient < deviation correction amount < Mout × second coefficient). More preferably, the first coefficient is a value of 1 / 1024 or more, and the second coefficient is a value of 1 / 256 or less. Also, the deviation correction amount may be gradually changed.

[0035] By setting the deviation correction amount to a value proportional to the control output Mout, appropriate deviation correction can be performed even when the driving speed or torque value changes. Also, by setting the deviation correction amount to a value sufficiently small with respect to the control output Mout, deviation correction can be performed without causing a sense of incongruity in the video.

[0036] Next, in step S105, the lens control unit 206 calculates a control output Mout2 for deviation correction by subtracting the calculated deviation correction amount from the control output Mout. By using the calculated control output Mout2, the speed of the zoom lens 101 can be finely adjusted, bringing the lens position Lposi closer to the motor position Mposi.

[0037] In step S106, the lens control unit 206 does not perform deviation correction, so it adopts control output Mout as control output Mout2.

[0038] Next, the deviation correction in this embodiment will be explained with reference to Figure 6. Figure 6 is a schematic diagram illustrating the deviation correction in this embodiment. In Figure 6, the horizontal axis represents time, the vertical axis in the upper part of Figure 6 represents the control output, and the vertical axis in the lower part of Figure 6 represents the position. Note that in Figure 6, the operation up to state 2 is the same as the operation without deviation correction shown in Figure 4, so the explanation is omitted.

[0039] State 4 is a state in which the discrepancy between the lens position Lposi and the motor position Mposi that occurred in State 2 is being corrected, and the lower part of Figure 6 shows how the discrepancy is gradually being corrected. The upper part of Figure 6 shows that the control output Mout2 after discrepancy correction is made smaller than the normal control output Mout, and as a result the lens speed decreases in relation to the command speed (change in command position), and the discrepancy can be corrected. When the discrepancy amount diffLM falls below the threshold X, the lens control unit 206 stops discrepancy correction and switches to normal motor position-based control (State 5).

[0040] As described above, in this embodiment, when the amount of deviation between the motor position and the lens position exceeds a threshold X (first threshold), the lens control unit 206 determines a deviation correction amount for the control output Mout to reduce the amount of deviation. For example, when the amount of deviation exceeds the threshold X, the lens control unit 206 calculates a deviation correction amount according to the control output Mout and adds the deviation correction amount to the control output Mout to determine a deviation correction amount that brings the lens position closer to the motor position or command position.

[0041] According to this embodiment, in motor position-based control, it is possible to improve the driving accuracy of the lens position so as not to cause any unnaturalness in the image. [Examples]

[0042] Next, Embodiment 2 of the present invention will be described. In this embodiment, components similar to those described in Embodiment 1 are indicated by the same reference numerals, and their descriptions are omitted. In Embodiment 1, in order to improve the controllability of the zoom lens 101 when it falls under its own weight, a method for correcting the discrepancy between the motor position and the lens position that occurs with the motor position base control was described after applying motor position base control. However, under conditions where unintended speed fluctuations due to the self-weight fall of the zoom lens 101 cannot occur, lens position base control is superior in terms of speed fluctuation and driving accuracy. Therefore, it is preferable to switch between motor position base control and lens position base control depending on the situation. In this embodiment, the problems that arise when switching and countermeasures will be described.

[0043] Referring to Figure 7, the challenges in switching from motor position-based control to lens position-based control will be explained. Figure 7 is a schematic diagram illustrating the challenges in this embodiment. In Figure 7, the horizontal axis represents time, the vertical axis in the upper part of Figure 7 represents the control output, and the vertical axis in the lower part of Figure 7 represents position. State 4 is the state in which the discrepancy between the lens position Lposi and the motor position Mposi that occurred in motor position-based control is being corrected, and is the same as State 4 in Embodiment 1.

[0044] State 20 shows the operation when switching from motor position-based control to lens position-based control during deviation correction. The conditions for control switching will be described later. Also, since the motor position Mposi is not used from state 20 onwards, the motor position Mposi is omitted from Figure 7 from state 20 onwards.

[0045] The control output Lout for lens position-based control is a value corresponding to the deviation between the command position Ctlpos and the lens position Lposi, as expressed by the calculation formula (2) above. Therefore, when switching to state 20, if the deviation between the command position Ctlpos and the lens position Lposi is large, a large reverse output corresponding to that deviation is generated, as shown in the upper part of Figure 7. As a result, the zoom lens 101 decelerates rapidly or moves in the reverse direction, resulting in an unnatural movement in the image.

[0046] State 21 is the state after the discrepancy has been resolved, and it is the normal operation of lens position-based control in which the lens position Lposi follows the change in the command position Ctlpos.

[0047] Next, with reference to Figure 8, the countermeasures (offset correction processing) for this problem will be explained. Figure 8 is a flowchart of the offset correction processing in this embodiment.

[0048] First, in step S201, the lens control unit 206 selects either motor position-based control (first control) or lens position-based control (second control). If at least one of the following conditions is met, the motor current value is greater than the current threshold, the lens drive speed is faster than the speed threshold, the start of lens movement is detected, and the reversal of the lens's direction of movement is detected, the first control is switched to the second control. However, the conditions are not limited to these.

[0049] If the conditions in step S201 are met, the process proceeds to step S202 to perform lens position-based control. On the other hand, if the conditions in step S201 are not met, the process proceeds to step S210 to perform motor position-based control. Here, we will briefly explain why lens position-based control is suitable in the cases where the above three conditions are met.

[0050] (When the current value is greater than the current threshold) Velocity fluctuations due to gravity fall can occur under conditions where the driving torque is small, i.e., when the current value is small. When the current value is large, gravity fall cannot occur, so it is appropriate to select lens position-based control.

[0051] (When the lens drive speed is faster than the speed threshold) When the lens drive speed exceeds the speed of gravity-induced fall, no velocity fluctuations due to gravity-induced fall occur, making it appropriate to select lens position-based control.

[0052] (When the lens starts moving or reverses direction) Regarding the movement of the lens when it starts moving or when it reverses direction, lens position-based control is suitable when considering the position calculation error when determining the motor position from the current value (back electromotive force) mentioned above. In other words, if the driving torque (static friction) is large when starting to move from a stopped state, the current value may continue to flow while the operation of motor 201 is locked. As a result, the motor position calculated based on the current value changes, which can lead to insufficient control output required for starting movement, causing a delay in starting movement.

[0053] Furthermore, contrary to the above, there are conditions under which motor position-based control is preferable for starting movement and reversing. This is when, in a state of discrepancy, the driving direction at the start of movement or reversing is in a direction that would reduce the discrepancy if motor position-based control were performed. In this case, the motor 201 moves only within the backlash section along with the change in command position, or the motor 201 moves in the opposite direction to the zoom lens 101. In other words, since the discrepancy can be quickly corrected by performing motor position-based control, it is preferable to select motor position-based control in order to shorten the discrepancy correction time. After the discrepancy correction is completed, it is preferable to switch to lens position-based control, taking into account the effect of the position calculation error described above.

[0054] After lens position-based control is selected in step S201, the process transitions to step S202. In step S202, the lens control unit 206 determines whether the previous control (control of the previous sample in the specified sample cycle) was motor position-based control. If the previous control was motor position-based control, the process transitions to step S203. On the other hand, if the control was not motor position-based control, the process transitions to step S204.

[0055] In step S203, the lens control unit 206 calculates the difference diffLM between the motor position Mposi and the lens position Lposi, and sets it as the offset amount OffsetPosi.

[0056] Next, in step S204, the control output Lout' is calculated by subtracting the offset amount OffsetPosi from the difference between the command position Ctlpos and the lens position Lposi in the calculation formula (2) described above, and then multiplying by Gain. The control output Lout' is an output that takes into account the difference diffLM between the lens position Lposi and the motor position Mposi, and at the moment of switching from motor position-based control to lens position-based control, the same output as the control output Mout is generated. Therefore, at the timing of switching to lens position-based control, an output equivalent to the control output of the previous control is generated, so a smooth switch can be achieved without causing any unnaturalness in the image.

[0057] Next, in step S204, the lens control unit 206 performs control switching while taking the offset amount OffsetPosi into consideration, enabling smooth switching. However, there is a discrepancy between the command position and the lens position that corresponds to the offset amount. In other words, the driving accuracy of the lens position is reduced, so it is preferable to reduce the offset amount.

[0058] Next, in step S205, the lens control unit 206 determines whether the offset amount OffsetPosi exceeds the threshold X. If the offset amount OffsetPosi exceeds the threshold X, the system proceeds to step S206 to reduce the offset amount. On the other hand, if the offset amount is less than or equal to the threshold X, the system proceeds to step S209. The threshold X is, as in Example 1, a value that is sufficiently small to, for example, the value required as the driving accuracy of the lens position.

[0059] In step S206, the lens control unit 206 calculates an offset correction amount for the control output Lout' in order to reduce the offset amount OffsetPosi. Here, the offset amount OffsetPosi is a position dimension, and the offset correction amount is a control output dimension. The offset correction amount can be calculated, for example, by multiplying the control output Lout' by a constant gain corG. The value of the constant gain corG is preferably in the range of 1 / 200 to 1 / 1000. Similar to the deviation correction in Embodiment 1, by making the offset correction amount a value proportional to the control output Lout', appropriate offset correction can be performed even if the drive speed or torque value changes. Furthermore, by making the offset correction amount a sufficiently small value relative to the control output Lout', offset correction can be performed without causing any unnaturalness in the image.

[0060] Next, in step S207, the lens control unit 206 calculates the offset amount corresponding to the offset correction amount as offset correction amount / gain. The lens control unit 206 then updates the offset amount OffsetPosi by subtracting the calculated value from the offset amount OffsetPosi. As a result, the offset amount OffsetPosi gradually decreases.

[0061] Next, in step S208, the lens control unit 206 calculates the control output Lout2 for offset correction by subtracting the calculated offset correction amount from the control output Lout', and uses this as the final control output. As a result, if the lens position is ahead of the command position, the zoom lens 101 is decelerated. On the other hand, if the lens position is behind the command position, the zoom lens 101 is accelerated. This allows the offset to be gradually eliminated.

[0062] In step S209, the lens control unit 206 adopts the control output Lout' as the final control output Lout2 because offset correction is not required.

[0063] In this way, when switching from motor position-based control to lens position-based control, the lens control unit 206 determines the offset amount according to the amount of deviation during the motor position-based control before the switch. Then, when switching to lens position-based control after the switch, the lens control unit 206 calculates a second output value based on the lens position and the offset amount, calculates an offset correction amount according to the second output value, and corrects the second output value using the offset correction amount to reduce the amount of deviation.

[0064] Next, we will describe the process when motor position-based control is selected in step S201. In step S210, the lens control unit 206 determines whether the previous control was lens position-based control or not. If the previous control was lens position-based control, the process proceeds to step S211. On the other hand, if the previous control was not lens position-based control, the process transitions to step S101.

[0065] In step S211, the lens control unit 206 sets the motor position Mposi as the sum of the lens position Lposi and the offset amount OffsetPosi. In other words, the output of the lens position-based control immediately before switching is taken over as the output of the motor position-based control. This makes it possible to reduce output fluctuations during switching. Furthermore, the motor position used in the motor position-based control is not the absolute position detected by the motor position detection unit 204, but is based on the lens position considering the offset amount OffsetPosi immediately before switching, and control is performed using the relative position from that reference. That is, when switching from the second control to the first control, the lens control unit 206 sets the lens position at the time of switching as the motor position, and then utilizes the relative position change of the motor position. Steps S101 onwards can be performed in the same way as the process described in Embodiment 1.

[0066] Next, with reference to Figure 9, the output before and after control switching in this embodiment and the offset correction in lens position-based control will be explained. Figure 9 is a schematic diagram illustrating the offset correction in this embodiment.

[0067] State 4 is the same as the operation shown in Figure 7, so its explanation is omitted. In State 23, as shown in the lower part of Figure 9, the lens position Lposi does not change during control switching, and the offset is gradually eliminated. The upper part of Figure 9 shows the relationship between the control output Lout' considering the offset and the control output Lout2 for offset correction. The control output Lout' is equivalent to the control output Mout without deviation correction in motor position-based control in State 4, and the final control output Lout2 is equivalent to the control output Mout2 after deviation correction in motor position-based control in State 4. Therefore, the lens position can be corrected by continuing the deviation correction in motor position-based control as offset correction in lens position-based control.

[0068] State 24 is the state after the offset amount has fallen below the threshold X, and the control output Lout2 becomes the control output Lout of the normal lens position-based control.

[0069] According to this embodiment, it is possible to eliminate the visual inconsistency when switching between motor position-based control and lens position-based control, and to improve the accuracy of lens position drive so as not to cause visual inconsistencies.

[0070] Although the embodiments described the driven object as a lens, the driven object is not limited to lenses and can be applied to other optical elements such as aperture diaphragms.

[0071] (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0072] According to each embodiment, it is possible to provide a drive device, an optical device, a control method for the drive device, and a program that can improve the driving accuracy of the position of an optical element.

[0073] Each embodiment's disclosure includes the following configuration and method. (Composition 1) A motor that drives the optical element, A first detection unit for detecting the position of the motor, A second detection unit for detecting the position of the optical element, The system includes a control unit that performs a first control, which controls the position of the motor based on a first output value corresponding to the difference between a command position corresponding to user operation and the position of the motor. The drive device is characterized in that, when the amount of deviation between the position of the motor and the position of the optical element exceeds a first threshold, the control unit determines a correction value for the first output value to reduce the amount of deviation. (Configuration 2) The drive device according to configuration 1, characterized in that, when the deviation amount exceeds the first threshold, the control unit calculates the correction value according to the first output value and adds the correction value to the first output value. (Composition 3) The drive device according to configuration 1 or 2, characterized in that the first threshold value is less than or equal to the stopping accuracy of the position of the optical element. (Composition 4) The drive device according to any one of configurations 1 to 3, characterized in that the correction value is within the range between the value obtained by multiplying the first output value by a first coefficient and the value obtained by multiplying the first output value by a second coefficient. (Composition 5) The aforementioned first coefficient is a value of 1 / 1024 or greater. The drive device according to configuration 4, characterized in that the second coefficient is a value of 1 / 256 or less. (Composition 6) The drive device according to any one of configurations 1 to 5, characterized in that the control unit determines the correction value so as to bring the position of the optical element closer to the position of the motor or the command position. (Composition 7) The system further includes a second detection unit for detecting the position of the optical element, The drive device according to any one of configurations 1 to 6, characterized in that the control unit controls the position of the optical element by switching between the first control and the second control, which controls the position of the optical element by a second output value corresponding to the difference between the command position and the position of the optical element. (Composition 8) The control unit, when switching from the first control to the second control, The offset amount is determined according to the amount of deviation during the first control before the switchover. During the second control after switching, the second output value is calculated based on the position and offset amount of the optical element. The offset correction amount is calculated according to the second output value, The drive device according to configuration 7, characterized in that the second output value is corrected using the offset correction amount to reduce the deviation amount. (Composition 9) The optical apparatus according to configuration 7 or 8, characterized in that the control unit switches the first control to the second control when at least one of the following conditions is met: the motor current value is greater than a current threshold; the speed of the optical element is faster than a speed threshold; the start of movement of the optical element is detected; and the reversal of the direction of movement of the optical element is detected. (Composition 10) The optical apparatus according to any one of configurations 7 to 9, characterized in that the control unit performs the first control when the amount of deviation between the position of the optical element and the position of the motor is reduced by the first control when the optical element starts moving or reverses direction, and performs the second control under other conditions. (Composition 11) The optical apparatus according to any one of configurations 7 to 10, characterized in that when the control unit switches from the second control to the first control, it sets the position of the optical element at the time of switching to the position of the motor, and then utilizes the relative position change of the position of the motor. (Composition 12) An optical device characterized by having a drive device according to any one of configurations 1 to 11 and the optical element. (Method 1) A step of detecting the position of the motor that drives the optical element, A step of detecting the position of the optical element, The process includes the step of controlling the position of the motor using a first output value corresponding to the difference between a command position corresponding to user operation and the position of the motor, A control method for a drive device, characterized in that, in the step of controlling the position of the motor, if the amount of deviation between the position of the motor and the position of the optical element exceeds a first threshold, a correction amount for the first output value is determined to reduce the amount of deviation. (Composition 13) A program characterized by causing a computer to execute the control method for the drive device described in Method 1.

[0074] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. [Explanation of symbols]

[0075] 101 Zoom lens (optical element) 200 Drive unit (drive device) 201 Motor 204 Motor position detection unit (first detection unit) 205 Lens position detection unit (second detection unit) 206 Lens Control Unit (Control Unit)

Claims

1. A motor that drives the optical element, A first detection unit for detecting the position of the motor, A second detection unit for detecting the position of the optical element, The system includes a control unit that performs a first control, which controls the position of the motor based on a first output value corresponding to the difference between a command position corresponding to user operation and the position of the motor. The drive device is characterized in that, when the amount of deviation between the position of the motor and the position of the optical element exceeds a first threshold, the control unit determines a correction value for the first output value to reduce the amount of deviation.

2. The drive device according to claim 1, characterized in that, when the deviation amount exceeds the first threshold, the control unit calculates the correction value according to the first output value and adds the correction value to the first output value.

3. The drive device according to claim 1, characterized in that the first threshold value is less than or equal to the stopping accuracy of the position of the optical element.

4. The drive device according to claim 1, characterized in that the correction value is within the range between the value obtained by multiplying the first output value by a first coefficient and the value obtained by multiplying the first output value by a second coefficient.

5. The first coefficient is a value of 1 / 1024 or greater. The drive device according to claim 4, characterized in that the second coefficient is a value of 1 / 256 or less.

6. The drive device according to claim 1, characterized in that the control unit determines the correction value so as to bring the position of the optical element closer to the position of the motor or the command position.

7. The system further includes a second detection unit for detecting the position of the optical element, The drive device according to claim 1, characterized in that the control unit controls the position of the optical element by switching between the first control and the second control, which controls the position of the optical element by a second output value corresponding to the difference between the command position and the position of the optical element.

8. The control unit, when switching from the first control to the second control, The offset amount is determined according to the amount of deviation during the first control before the switchover. During the second control after the switchover, the second output value is calculated based on the position of the optical element and the offset amount. The offset correction amount is calculated according to the second output value, The drive device according to claim 7, characterized in that the second output value is corrected using the offset correction amount to reduce the deviation amount.

9. The optical apparatus according to claim 7, characterized in that the control unit switches the first control to the second control when at least one of the following conditions is satisfied: the motor current value is greater than a current threshold; the speed of the optical element is faster than a speed threshold; the start of movement of the optical element is detected; and the reversal of the direction of movement of the optical element is detected.

10. The optical apparatus according to claim 7, characterized in that the control unit performs the first control when the amount of deviation between the position of the optical element and the position of the motor is reduced by the first control when the optical element starts moving or reverses direction, and performs the second control under other conditions.

11. The optical apparatus according to claim 7, characterized in that when the control unit switches from the second control to the first control, it sets the position of the optical element at the time of switching to the position of the motor, and then utilizes the relative position change of the position of the motor.

12. An optical device comprising a drive device according to any one of claims 1 to 11 and the optical element.

13. A step of detecting the position of the motor that drives the optical element, A step of detecting the position of the optical element, The process includes the step of controlling the position of the motor using a first output value corresponding to the difference between a command position corresponding to user operation and the position of the motor, A control method for a drive device, characterized in that, in the step of controlling the position of the motor, if the amount of deviation between the position of the motor and the position of the optical element exceeds a first threshold, a correction amount for the first output value is determined to reduce the amount of deviation.

14. A program characterized by causing a computer to execute the control method for the drive device described in claim 13.

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