KR101598255B1 - Apparatus and method for controlling actuator in optical image stabilizer and optical image stabilizer using the same - Google Patents

Abstract

An actuator control apparatus of an optical image stabilization apparatus according to the present invention comprises: a distance calculation unit for calculating a distance based on an output of a motion sensor for detecting camera shake; A shake frequency determining unit for determining whether the shaking motion is a shaking motion of a low frequency based on the distance data output from the distance calculating unit; And a control pattern generator for dividing the magnitude of the output of the proportional-integral-derivative (PID) controller into a plurality of parts and providing the same to the actuator driver when the camera-shake is a low-frequency motion, It is possible to prevent a sudden change in the control value and prevent an oscillation signal from being output to the actuator, thereby preventing image blur due to low-frequency camera shake.

Description

TECHNICAL FIELD The present invention relates to an actuator control apparatus and method for an optical image stabilizer, and an optical image stabilizer using the same.

The present invention relates to an apparatus and method for controlling an actuator of an optical image stabilization apparatus capable of stabilizing an image by minimizing an output of an oscillation signal from an actuator by preventing a sudden change of a control value of an actuator driving unit when a camera shake occurs at a low frequency.

The function of the optical image stabilizer (OIS) is to adjust the center of the image so that the center of the image always coincides with the optical axis of the camera by controlling the actuator and moving the lens module in the opposite direction to the camera shake . The most important part of this function is the value of data output from the gyro sensor, which is a motion sensor. This is because, depending on the value of the data output from the gyro sensor, how much the current lens module is to be moved in the X axis or the Y axis is determined.

However, even if the position of the lens module to be moved is determined by the value of the data output from the gyro sensor, it is difficult to accurately position the lens module at the target position. The greatest reason is the control performance of a proportional-integral-derivative (PID) control unit.

The PID control unit calculates a final position shift value at which the lens module should move based on the output of the hall sensor and the output of the gyro sensor, which detect the actual moving distance of the lens module.

The PID control unit transmits the calculated final position movement value to an actuator driving unit including a pulse width modulation (PWM) control unit or a linear control unit, and the actuator driving unit outputs a driving signal to the actuator. An actuator such as a voice coil motor (VCM) operates according to a driving signal to move the lens module by a position shift value.

The PID controller changes its performance depending on how the ratio of the three coefficients, Kp, K, and Kd, is optimized in a given environment. The proportional coefficient (Kp) is the current control value, the integral coefficient (Ki) is the past control value, and the derivative coefficient (Kd) is related to the future control value.

The proportional coefficient (Kp) relates to how many weights are to be added to the current error, and the integral coefficient (Ki) is related to the integration of the past error to the current reference, and the derivative coefficient (Kd ) Is related to what degree of future value and direction will control the error.

Once the setting of the PID controller is completed, it is necessary to determine how much the current value should be weighted, how much the past value should be accumulated, and in which direction to move in the future. , Kd). Therefore, a problem arises. Because of this problem, the PID coefficients optimized for a particular environment may be the worst case in other specific environments.

In general, when designing the PID control section for preventing the shaking motion, one PID coefficient is determined from the low frequency region to the high frequency region (1 Hz to 15 Hz) to perform the PID control. Therefore, when a low frequency shake occurs, an excessive forced oscillation A signal may be output.

The control values of the PWM controller and the linear controller included in the actuator driver are calculated and provided by the PID controller. Therefore, the actuator operation is not stabilized according to the value output from the PID control unit, and the oscillation signal is forcibly outputted. This phenomenon occurs because the PID coefficient (Kp, Ki, Kd) of the PID controller does not match the current frequency situation and the output signal of the actuator oscillates +/- at the periphery of the reference position.

Since OIS must work well in all shakes of all frequency bands, it is difficult to control, and it is difficult to establish an optimization environment only for low frequency shakes that do not occur frequently. That is, in order to operate the OIS as a whole, it was necessary to trade-off the precise control of the low-frequency region. For this reason, OIS seems to not operate or the image is excessively swung in slow moving shakes having low- Respectively. It is difficult to solve this problem with the general PID control method for OIS control.

The patent document described in the following prior art documents relates to a camera shake correction method and apparatus of a camera module for a mobile device and uses a PID coefficient having a maximum control resolution to calculate a reference value Rate PID controller that allows control over a number of times using a relatively small control cycle compared to conventional PID control during a basic sampling period to be updated to reach a desired reference value. The following patent document performs multi-rate PID control so as to continuously control the driving unit within a predetermined kinetic frictional force by continuously operating the driving unit for a predetermined period of a control signal for controlling the driving unit. However, the following patent document does the same PID control for all the camera shake frequencies, although it can prevent the image sensor driving unit from being biased in one direction to reduce the motion and improve the performance of the controller recovering from strong external shocks It is not possible to prevent a sudden change in the control value of the actuator driving unit when a camera shake occurs at a low frequency.

KR 10-0819301 B1

An embodiment of the present invention has been made to solve the above-mentioned problems of the prior art, and one embodiment of the present invention is to solve the problems of the conventional art in which a sudden change in the control value of the actuator driving unit is prevented at the time of low- An object of the present invention is to provide an apparatus for controlling an actuator of an optical image stabilization apparatus which can prevent image blur due to low-frequency hand movement by preventing an oscillation signal from being outputted.

Another problem to be solved by one embodiment of the present invention is to prevent a sudden change in the control value of the actuator driving unit when an unintentional hand movement occurs and to prevent an oscillator signal from being outputted from the actuator And an object of the present invention is to provide an actuator control method of an optical image stabilization device capable of preventing image blur due to low-frequency camera shake.

Another object of the present invention is to prevent a sudden change in the control value of the actuator driving unit when an unintentional hand movement occurs and to prevent an oscillation signal from being output from the actuator to prevent image blur due to low- And an optical image stabilization device capable of correcting an unstable image.

According to an aspect of the present invention, there is provided an apparatus for controlling an actuator of an optical image stabilizer,

A distance calculation unit for calculating a distance based on an output of a motion sensor for detecting camera shake;

A shake frequency determining unit for determining whether the shaking motion is a shaking motion of a low frequency based on the distance data output from the distance calculating unit; And

And a control pattern generator for dividing the magnitude of the output of the proportional-integral-differential (PID) control unit into a plurality of parts and providing them to the actuator driver one by one when the camera-shake is a low-frequency camera-shake.

In the actuator control apparatus of the optical image stabilization apparatus according to an embodiment of the present invention, the actuator may include a voice coil motor (VCM).

In the actuator control apparatus of an optical image stabilization apparatus according to an embodiment of the present invention, the control pattern generator may linearly or inversely exponentially divide the output of the PID control unit, One for each of the actuator driving units.

In an actuator control apparatus of an optical image stabilization apparatus according to an embodiment of the present invention, when the output of the PID control unit is divided by an inverse exponential function, and when the control pattern generation unit outputs to the actuator driving unit the output of the PID control unit 80%, the control pattern generator may gradually provide the remaining 20% of the output to the actuator driver.

In the actuator control apparatus of the optical image stabilization apparatus according to the embodiment of the present invention, the actuator driving unit may include at least one of a pulse width modulation (PWM) control unit and a linear control unit and a H- . ≪ / RTI >

In the actuator control apparatus of the optical image stabilization apparatus according to an embodiment of the present invention, the shake frequency determining unit may perform a moving average filtering on the output of the distance calculating unit and differentiate the output of the distance calculating unit to detect the number of peaks generated during a predetermined period Thereby determining the shaking frequency, and when the determined shaking frequency is equal to or lower than the reference value, the shaking motion can be determined as a shaking motion of a low frequency.

In addition, in the actuator control apparatus of the optical image stabilization apparatus according to the embodiment of the present invention, the reference value may include 3 Hz.

An actuator control apparatus of an optical image stabilization apparatus according to an embodiment of the present invention includes an image sensor moved by an actuator driven by the actuator driving unit or an output of a hall sensor for detecting a moving distance of a lens unit, Wherein the control pattern generator applies a control signal to the switching unit to prevent the output of the Hall sensor from being provided to the PID controller when the shaking motion is a low-frequency shaking motion .

Further, in the actuator control apparatus of the optical image stabilization apparatus according to the embodiment of the present invention, the optical stabilization apparatus includes an optical stabilization apparatus included in a smart phone, and the motion sensor is provided in the optical stabilization apparatus And may include an included gyro sensor.

According to another aspect of the present invention, there is provided an optical image stabilizer,

A motion sensor for detecting camera shake;

An actuator for moving the image sensor or the lens unit of the camera module in a direction opposite to the camera-shake direction in response to the camera-shake;

An actuator driving unit for driving the actuator;

A hall sensor for sensing a moving distance of the image sensor or the lens unit moved by the actuator;

A PID controller for outputting an actuator control signal based on a difference between a travel distance calculated based on the output of the motion sensor and a travel distance of the image sensor or the lens unit obtained through the hole sensor;

A distance calculation unit for calculating a distance based on the output of the motion sensor;

A shake frequency determining unit for determining whether the shaking motion is a shaking motion of a low frequency based on the distance data output from the distance calculating unit; And

And a control pattern generator for dividing the output of the proportional-integral-derivative (PID) controller into a plurality of parts and providing the outputs to the actuator driver one by one when the camera-shake is a low-frequency camera-shake.

In the optical image stabilization apparatus according to an embodiment of the present invention, the actuator may include a voice coil motor (VCM).

In the optical image stabilization apparatus according to an embodiment of the present invention, the control pattern generator may linearly divide or inversely exponentially divide the output of the PID controller, and output the divided outputs to the actuator driver one by one .

In the optical image stabilization apparatus according to an embodiment of the present invention, when the output of the PID control unit is divided by an inverse exponential function and the control pattern generation unit provides the actuator drive unit with 80% of the output of the PID control unit In one case, the control pattern generator may gradually provide the remaining 20 percent of the output to the actuator driver.

In the optical image stabilization apparatus according to an embodiment of the present invention, the actuator driving unit may include at least one of a pulse width modulation (PWM) control unit and a linear control unit, and an H- have.

In the optical image stabilization apparatus according to an embodiment of the present invention, the shaking motion frequency determination unit may perform moving average filtering on the output of the distance calculation unit and differentiating the output of the distance calculation unit to detect the number of peaks generated during a predetermined period, And if it is determined that the determined shaking frequency is equal to or lower than the reference value, the shaking motion can be determined as a shaking motion of a low frequency.

In the optical image stabilization apparatus according to an embodiment of the present invention, the reference value may include 3 Hz.

Further, in the optical image stabilization apparatus according to an embodiment of the present invention, an output of a hall sensor for sensing a moving distance of an image sensor or a lens unit moved by an actuator driven by the actuator driving unit is provided to the PID control unit The control pattern generator may apply a control signal to the switching unit to prevent the output of the hall sensor from being provided to the PID controller when the camera-shake is a low-frequency shaking motion.

In the optical image stabilization apparatus according to an embodiment of the present invention, the optical image stabilization apparatus may include an optical image stabilizer included in a smart phone, and the motion sensor may include a gyro sensor included in the optical image stabilizer . ≪ / RTI >

According to another aspect of the present invention, there is provided an actuator control method for an optical image stabilization apparatus,

(A) calculating a distance based on an output of a motion sensor for detecting camera shake;

(B) determining an unintentional hand movement frequency based on distance data output from the distance calculation unit;

(C) determining whether the shaking motion is a shake of a low frequency based on the determined shaking frequency; And

(D) dividing the output of the PID controller into a plurality of parts and providing the outputs to the actuator driver one by one when the camera-shake is a low-frequency camera-shake.

In the method of controlling an actuator of an optical image stabilization apparatus according to an embodiment of the present invention, in the step (D), when the shaking motion is a low-frequency shaking motion, after the output of the hall sensor is not provided to the PID control unit, And dividing the output of the PID controller into a plurality of parts and providing the outputs to the actuator driver one by one.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may appropriately define the concept of a term in order to best describe its invention The present invention should be construed in accordance with the spirit and scope of the present invention.

According to the embodiment of the present invention, it is possible to optimally control the actuator of the OIS with respect to both the low-frequency and high-frequency handshake frequencies, thereby preventing blurring of the image regardless of the shaking frequency. Particularly, It is possible to prevent a sudden change in the control value and to prevent the output of the oscillation signal from the actuator, thereby preventing blurring of the image due to low-frequency camera shake.

1 is a block diagram showing an optical image stabilization apparatus including an actuator control apparatus of an optical image stabilization apparatus according to an embodiment of the present invention.
2 is a flowchart showing an actuator control method of an optical image stabilization apparatus according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention Should be construed in accordance with the principles and the meanings and concepts consistent with the technical idea of the present invention.

It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings.

Also, "first", "second", "one side". The terms "other" and the like are used to distinguish one element from another, and the element is not limited by the terms.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an optical image stabilization apparatus including an actuator control apparatus 100 of an optical image stabilization apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an optical image stabilization apparatus according to an embodiment of the present invention. Fig. 3 is a flowchart showing an actuator control method of the apparatus. Fig.

Hereinafter, an apparatus and method for controlling an actuator of an optical image stabilization apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.

According to an embodiment of the present invention, the current camera shake frequency is determined based on the output signal of the gyro sensor unit, and when the camera shake occurs at a low frequency, the actuator is controlled to move slowly by dividing the movement distance received from the PID controller. The movement distances of all the actuators are accumulated so as to be equal to the movement distances indicated by the original PID control unit, thereby preventing the oscillator signal from being outputted from the actuator in the event of low-frequency camera-shake.

In an embodiment of the present invention, a camera shake is divided into camera shake at high frequency and camera shake at low frequency, and a control signal is output to the actuator driving unit at the time of camera shake at a low frequency to output an oscillation signal at the time of camera shake at low frequency prevent.

In OIS, the problem of low-frequency hand movement is always a problem. When the value set by the PID control unit is larger than the change of the hand movement of the low frequency in order to compensate for the hand movement of the low frequency, an oscillation signal is generated in the actuator. The control value of the actuator driving unit received from the PID control unit when the camera shake occurs is divided and provided to the actuator driving unit in a progressive manner to prevent the oscillation signal from being outputted from the actuator, thereby minimizing blurring of the image due to low- In addition, when a camera shake occurs at a high frequency, the control value of the actuator driving unit is supplied from the PID control unit to the actuator driving unit without any operation.

In the embodiment of the present invention, a voice coil motor (VCM) is controlled as the actuator of the OIS. However, the actuator control device of the optical image stabilization device according to the embodiment of the present invention But not limited to, any type of actuator that controls the movement of the lens module in the OIS.

1, an optical camera shake correcting apparatus including an actuator control apparatus 100 of an optical camera shake correcting apparatus according to an embodiment of the present invention includes a gyro sensor unit 102 for detecting camera shake, A hall sensor 124 for sensing the actual moving distance of the VCM 120, a gyro sensor unit 102 for detecting the actual moving distance of the VCM 120, A PID controller 104 for outputting an actuator control signal based on a difference between a calculated travel distance based on the output of the gantry sensor 124 and a travel distance of the VCM 120 obtained through the hall sensor 124, Calculates the distance based on the output of the Hall sensor (102), and determines whether the shaking motion is a shaking of a low frequency based on the calculated distance, and if the shaking motion is a shaking of a low frequency, D control unit 104. The actuator control unit 100 divides the magnitude of the actuator control signal output from the PID control unit 104 into a plurality of portions and sequentially outputs the magnitudes of the actuator control signals one by one, And an actuator driver 130 for driving the VCM 120 based on the output of the controller 100.

The actuator control apparatus 100 includes a distance calculation unit 106 for calculating a distance based on the output of the gyro sensor unit 102, a moving average filter for distance data output from the distance calculation unit 106, (PID) control section, when the shaking motion is a shaking motion of a low frequency, based on the shake frequency of the shaking motion, And outputs the output of the Hall sensor 124 to the actuator driver 130 according to the control signal CS of the control pattern generator 110. The control pattern generating unit 110 generates the PID And a switching unit 112 that is provided or not provided to the control unit 104.

The actuator driving unit 130 includes a control unit for controlling a pulse width modulation (PWM) 114 that receives the output of the control pattern generation unit 100, a linear control unit 116, PWM (Pulse Width Modulation) controller 114 and an H-bridge 118 for receiving the output of the linear controller 116 and driving the VCM 120.

The operation of the actuator control apparatus 100 of the optical image stabilization apparatus according to the embodiment of the present invention will be described below.

The distance calculation unit 106 calculates the distance based on the gyro data output from the gyro sensor unit 102 for detecting the shaking motion. The shaking frequency determining unit 108 determines whether the shaking motion is a shaking motion of a low frequency based on the distance data output from the distance calculating unit 106. [

The shaking motion frequency determination unit 108 performs a moving average filtering on the distance data output from the distance calculation unit 106 and determines how many polarities change from the differential value of the moving average filtered data. For example, if you look at 33ms, you can detect how many partial peaks occur during this criterion and calculate the handshake frequency as "peak count / time".

The hand-shake frequency determining unit 108 determines that the hand-shake is a hand-shake at a low frequency when the calculated hand-shake frequency is a reference value, for example, 3 Hz or less.

The control pattern generation unit 110 first applies the control signal CS to the switching unit 112 when the shaking motion is recognized as the shaking of the low frequency based on the output of the shaking motion frequency determination unit 108, The switching unit 112 is opened and the output of the Hall sensor 124 is not provided to the PID controller 104. [

Since the hall sensor 124 itself has an error, the error is amplified by the PID control unit 104 when the PID control unit 104 continuously receives the feedback of the Hall sensor 124, especially when a low-frequency camera shake occurs. Therefore, the control pattern generation unit 110 controls the switching unit 112 to prevent the output of the hall sensor 124 from being applied to the PID control unit 104, thereby preventing the error from being amplified. Then, the control pattern generator 110 receives the output of the PID controller 104, divides the output size of the PID controller 104 into a plurality of parts, and provides the output to the actuator driver 130 one by one.

The operation of the control pattern generator 110 will be described below in detail.

The control pattern generation unit 110 receives the frequency and period information and calculates a control value at each starting point of one PWM control or linear control. For example, if the current low frequency movement has occurred, the size of the output received from the PID controller 104 is 50, and the total movement distance to which the lens unit 122 should move in the camera module (not shown) is +/- And the linear control range of the PID control is 400. Fig.

200/400 is 0.5 탆 / 1 PWM, so that when the PWM is changed by one unit, the lens portion 122 moves by 0.5 탆. 50 means that the lens unit 122 is moved by 25 占 퐉 in the + direction from the conventional one. Assuming that the PID control has a cycle of 20 KHz and the PWM control has a cycle of 200 KHz, Other control values are applied. The applied value may be linearly 1/10 or larger depending on the current frequency and the magnitude of the control value, or may be inversely exponential.

In one embodiment of the present invention, the control pattern generator 110 linearly changes the size of the output of the PID controller 104 when the size of the output of the PID controller 104 is less than 10, And provides a total of ten outputs one by one to the PWM control unit 114 in sequence. If the magnitude of the output of the PID controller 104 is greater than or equal to 10, the magnitude of the output of the PID controller 104 is divided into an inverse exponential function and supplied to the PWM controller 114 one by one.

In the embodiment of the present invention, the size of the output of the PID controller 104 is determined to be linearly divided or inversely exponentially divided by comparing the size of the output of the PID controller 104 with the reference value 10, The reference value of 10 is not limited thereto but may be changed depending on the characteristics of the VCM and the VCM driving element related thereto.

When the output of the PID controller 104 is divided into the form of an inverse exponential function, the control pattern generator 110 controls the PWM controller 114 to prevent the VCM 120 from outputting an oscillation signal. The control pattern generation unit 110 applies the attenuation index to the remaining 20 percent of the output so that the lens unit 122 moves slowly to the target position. The reference value of 80 percent may be changed depending on the situation.

The control of the actual VCM 120 in the OIS acquires the gyro data of the gyro sensor unit 102 once, calculates the X and Y positions corresponding to the change of the gyro data, drives the PWM control unit 114, The objective of the present invention is to acquire and periodically check the actual distance that the lens unit 120 has moved the lens unit 122 with the hall sensor 124 and to reduce errors in the calculated position and the actual position.

For example, the output of the hall sensor 124 is read five times while the gyro data is read once. For this reason, there is actually a change in the output value of the five hall sensors 124 according to a change in one gyro data. In an embodiment of the present invention, the output value of the Hall sensor 124 gradually changes when the camera shake occurs at a low frequency.

When the value of the Hall sensor 124 is changed once, the PWM can be changed 10 times, so that the control pattern generating unit 110 outputs the value transmitted to the PWM control unit 114 by 1/10 And divides the PWM control value stepwise to move the lens unit 122 in a stepwise manner without dividing the lens unit 122 at one time. In this case, the values required to calculate the movement distance of the lens unit 122 are the calculation cycle, the update point and value of the gyro data, the change point of the PID value, and the control value of the changed PID.

2 is a flowchart illustrating an actuator control method of an optical image stabilization apparatus according to an embodiment of the present invention.

2, an actuator control method of an optical image stabilization apparatus according to an embodiment of the present invention will be described.

In step S200, the distance calculation unit 106 calculates the distance based on the angular velocity which is the output of the gyro sensor unit 102 that detects the shaking motion.

The output of the gyro sensor unit 102 is expressed by an angular velocity. By passing this through a low-pass filter that takes into account the cutoff, phase, and size, it is possible to obtain the angle information in which the ripple and drift are attenuated, and from this, the distance that the lens needs to travel can be calculated. The distance calculation unit 106 calculates the distance by which the lens should move due to camera shake based on the angular velocity output from the gyro sensor unit 102.

In step S202, the hand-shake frequency determining unit 108 determines the hand-shake frequency based on the distance data output from the distance calculating unit 106. [

The shaking motion frequency determination unit 108 performs a moving average filtering on the distance data output from the distance calculation unit 106 and determines how many polarities change from the differential value of the moving average filtered data. For example, if you look at 33ms, you can detect how many partial peaks occur during this criterion and calculate the handshake frequency as "peak count / time".

In step S204, the hand-shake frequency determining unit 108 determines that the hand-shake is a hand-shake of a low frequency when the calculated hand-shake frequency is a reference value, for example, 3 Hz or less.

In step S206, the control pattern generation unit 110 receives the output of the shake frequency determination unit 108 and applies the control signal CS to the switching unit 112 first when the shaking motion is a low-frequency shaking motion, (112) to an open state so that the output of the hall sensor (124) is not provided to the PID controller (104).

Since the hall sensor 124 itself has an error, the error is amplified by the PID control unit 104 when the PID control unit 104 continuously receives the feedback of the Hall sensor 124, especially when a low-frequency camera shake occurs. Therefore, the control pattern generation unit 110 controls the switching unit 112 to prevent the output of the Hall sensor 124 from being applied to the PID control unit 104 when a low-frequency camera shake occurs. Then, the control pattern generation unit 110 divides the output size of the PID control unit 104 into a plurality of parts, and sequentially supplies the divided outputs to the actuator driving unit 130 one by one.

In step S208, the control pattern generator 110 divides the output size of the PID controller 104 into a plurality of parts and sequentially outputs them to the PWM controller 114 or the linear controller 116 of the actuator driver 130 to provide.

For example, the control pattern generator 110 linearly divides the output size of the PID controller 104 by 1/10 when the size of the output of the PID controller 104 changes by a small value of less than 10 And provides a total of ten outputs to the PWM controller 114 one by one. If the magnitude of the output of the PID controller 104 is greater than or equal to 10, the magnitude of the output of the PID controller 104 is divided into an inverse exponential function and supplied to the PWM controller 114 one by one.

In the embodiment of the present invention, the size of the output of the PID controller 104 is determined to be linearly divided or inversely exponentially divided by comparing the size of the output of the PID controller 104 with the reference value 10, The reference value of 10 is not limited thereto but may be changed depending on the characteristics of the VCM and the VCM driving element related thereto.

In step S210, the control pattern generation unit 110 outputs the output of the PID control unit 104 as it is, based on the output of the shake frequency determination unit 108, when it is recognized that the shaking motion is not a low- To the PWM control unit (114) or the linear control unit (116) of the control unit (130).

In an embodiment of the present invention, the value output from the PID control unit 104 is controlled in hardware, while the PID control optimized for the camera module remains unchanged. Since the total amount of the current passed through the VCM is proportional to the moving distance of the camera lens part, according to the embodiment of the present invention, the effect of compensating for the shaking of low frequency is very large.

The primary goal is to avoid the oscillation of the camera lens by outputting an oscillation signal from the VCM, rather than the time required to travel to the target position in low-frequency hand shake. Therefore, by separately controlling the low-frequency control portion which is difficult to control the existing PID while using the existing PID control, it is possible to prevent the camera lens portion from oscillating in the +/- direction and ringing around the reference position, It is possible to prevent a blur of an image even when a camera shake occurs and obtain a clear image.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is clear that the present invention can be modified or improved.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

100: actuator control device 102: gyro sensor part
104: PID control unit 106: Distance calculation unit
108: Hand shake frequency determination unit 110: Control pattern generation unit
112: Switching unit 114: PWM control unit
116: Linear control unit 118: H-bridge
120: VCM 122: lens part
124: Hall sensor 130: Actuator driving part

Claims (20)

A distance calculation unit for calculating a distance to be moved by the image sensor or the lens unit based on the output of the motion sensor for detecting camera shake;
A shake frequency determining unit for determining whether the shaking motion is a shaking motion of a low frequency based on the distance data output from the distance calculating unit; And
And a control pattern generator for dividing the output of the proportional-integral-differential (PID) control unit into a plurality of parts and providing the divided output to the actuator driving unit when the camera-shake is a low-frequency camera-shake motion, An actuator control device of a device. The method according to claim 1,
Wherein the actuator includes a voice coil motor (VCM). The method according to claim 1,
Wherein the control pattern generator divides the output of the PID controller linearly or inversely exponentially and provides the divided outputs one by one to the actuator driver. The method of claim 3,
When the output of the PID controller is divided by an inverse exponential function and the control pattern generator provides the actuator driver with 80% of the output of the PID controller, the control pattern generator outputs the remaining 20% And an actuator for controlling the actuator of the optical image stabilizer. The method according to claim 1,
Wherein the actuator driving unit includes at least one of a pulse width modulation (PWM) control unit and a linear control unit, and an H-bridge. The method according to claim 1,
The shake frequency determining unit may determine a shake frequency by performing a moving average filtering on the output of the distance calculating unit and differentiating the number of peaks generated during a predetermined period,
And judges that the shaking motion is a shaking motion of a low frequency when the determined shaking motion frequency is equal to or lower than a reference value. The method of claim 6,
Wherein the reference value includes 3 Hz. The method according to claim 1,
Further comprising a switching unit for providing or not providing an output of an image sensor moved by an actuator driven by the actuator driving unit or an output of a hall sensor for detecting a moving distance of the lens unit to the PID control unit,
Wherein the control pattern generating unit applies a control signal to the switching unit to prevent the output of the hall sensor from being provided to the PID controller when the camera-shake is a low-frequency camera-shake. The method according to claim 1,
Wherein the optical shake correcting apparatus includes an optical shake correcting apparatus included in a smart phone and the motion sensor includes a gyro sensor included in the optical shake correcting apparatus. A motion sensor for detecting camera shake;
An actuator for moving the image sensor or the lens unit of the camera module in a direction opposite to the camera-shake direction in response to the camera-shake;
An actuator driving unit for driving the actuator;
A hall sensor for sensing a moving distance of the image sensor or the lens unit moved by the actuator;
A PID controller for outputting an actuator control signal based on a difference between a travel distance calculated based on the output of the motion sensor and a travel distance of the image sensor or the lens unit obtained through the hole sensor;
A distance calculation unit for calculating a distance that the image sensor or the lens unit should move based on the output of the motion sensor;
A shake frequency determining unit for determining whether the shaking motion is a shaking motion of a low frequency based on the distance data output from the distance calculating unit; And
And a control pattern generator for dividing the output of the proportional-integral-differential (PID) controller into a plurality of parts and providing the output to the actuator driver one by one when the camera-shake is a low-frequency camera- . The method of claim 10,
Wherein the actuator includes a voice coil motor (VCM). The method of claim 10,
Wherein the control pattern generator divides the output of the PID controller linearly or inversely exponentially and provides the divided outputs to the actuator driver. The method of claim 12,
When the output of the PID controller is divided by an inverse exponential function and the control pattern generator provides the actuator driver with 80% of the output of the PID controller, the control pattern generator outputs the remaining 20% In a progressive manner. The method of claim 10,
Wherein the actuator driving unit includes at least one of a pulse width modulation (PWM) control unit and a linear control unit, and an H-bridge. The method of claim 10,
The shake frequency determining unit may determine a shake frequency by performing a moving average filtering on the output of the distance calculating unit and differentiating the number of peaks generated during a predetermined period,
And determines that the shaking motion is a shaking motion of a low frequency when the determined shaking motion frequency is equal to or lower than a reference value. 16. The method of claim 15,
Wherein the reference value includes 3 Hz. The method of claim 10,
Further comprising a switching unit for providing or not providing an output of an image sensor moved by an actuator driven by the actuator driving unit or an output of a hall sensor for detecting a moving distance of the lens unit to the PID control unit,
Wherein the control pattern generator applies a control signal to the switching unit to prevent the output of the hall sensor from being provided to the PID controller when the camera-shake is a low-frequency camera-shake. The method of claim 10,
Wherein the optical shake correcting apparatus includes an optical shake correcting apparatus included in a smart phone, and the motion sensor includes a gyro sensor included in the optical shake correcting apparatus. (A) calculating a distance by which an image sensor or a lens unit should move based on an output of a motion sensor for detecting camera shake;
(B) determining an unintentional hand movement frequency based on distance data output from the distance calculation unit;
(C) determining whether the shaking motion is a shake of a low frequency based on the determined shaking frequency; And
(D) dividing the output of the PID controller into a plurality of parts and providing the outputs to the actuator driver one by one when the camera-shake is a low-frequency camera-shake. The method of claim 19,
In the step (D), if the shaking motion is a low-frequency shaking motion, the output of the hall sensor is not provided to the PID control unit, and the output of the PID control unit is divided into a plurality of parts and provided to the actuator driving unit And an actuator of the optical image stabilizer.

Images