JP2009128423A - Drive control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive control device, controlling the drive of an actuator including a driving member made of a shape memory alloy to drive a driven member with good positional accuracy. <P>SOLUTION: This drive control device 1 includes: a distortion quantity setting means 11 for setting a distortion quantity by each driving member so that the total distortion quantity value of each of the driving members gets equal to the displacement quantity of the driven member, and the distortion quantity by each driving member amounts to a distortion quantity at a reverse transformation start temperature or below of a shape memory alloy used, or at a martensitic transforation start temperature or above; an applied current value determination means 12 for determining a current value applied to each driving member based on each distortion quantity set in the distortion quantity setting means 11; and a current applying means 13 for applying a current of the current value determined in the applied current value determination means 12 to each driving member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drive control device that controls the drive of an actuator including a plurality of drive members made of a shape memory alloy.

  Shape memory alloys (hereinafter also referred to as SMA (Shape Memory Alloy)) are frequently used as drive members in actuators for various applications because of their high contraction speed and large displacement and stress. . In recent years, development for use as a drive member in an actuator for a small or ultra-small device such as a mobile device, a camera, or a MEMS (Micro Electro Machine System) has been advanced.

  Patent Document 1 discloses an example of an actuator device using SMA. The actuator device disclosed in Patent Document 1 is obtained by converting the movement of an SMA pipe, which is a part of the actuator device, into a vertical movement of a lever mechanism that is combined with a pressurizing spring.

  However, the actuator device using the SMA has a problem that the response speed when the shape is restored by cooling depends on the heat radiation and the cooling speed. Patent Document 2 discloses an actuator device that solves this problem. Unlike the actuator device described in Patent Document 1, the actuator device described in Patent Document 2 uses a plurality of SMAs. More specifically, an insulating thin film is sandwiched between SMA thin film pieces that generate heat and undergo warping deformation in response to energization, and the energization of each SMA thin film piece is made independent. As a result, the problem of the operation speed during the cooling extension of the SMA is improved, and the SMA plate material as a whole exhibits high responsiveness.

  As described above, the actuator device using the SMA is also used for driving an optical element typified by a camera lens. In the case of an actuator device that drives a lens of a camera or the like, it is required that the position of the lens can be held with high accuracy as well as preventing the actuator device from malfunctioning and extending its life. Actuator devices that satisfy these requirements are disclosed in Patent Documents 3 to 5 shown below.

  Patent Document 3 discloses a camera shutter actuator that uses a plurality of SMAs to prevent malfunction due to the ambient temperature of the SMA. A schematic diagram of the actuator device in Patent Document 3 is shown in FIG. The actuator device described in Patent Document 3 is an actuator device that rotates the rotation shaft 223 by the SMA wire 225 and the pressurizing spring 227 and moves the movable node 222 along the rail 224. Thus, the driven member 221 is moved to perform an opening / closing operation as a shutter. At this time, the SMA wire 226 is connected to the rotating shaft 223 on the side opposite to the SMA wire 225 so that the SMA wire 225 does not malfunction due to the environmental temperature of the SMA wire 225 becoming high. That is, even when the environmental temperature becomes high and the SMA wire 225 reaches the transformation start temperature, the SMA wire 225 and the SMA wire 226 cancel each other out. Therefore, the driven member 221 does not move.

  Patent Document 4 discloses an actuator device that reduces the stress generated in the wire and extends the repeated operation life. Note that the actuator device described in Patent Document 4 also uses a plurality of SMAs. A schematic diagram of the actuator device in Patent Document 4 is shown in FIG. The actuator device described in Patent Document 4 includes a tension spring 325 disposed between the fixed member and the drive member 11. The tension spring 325 stores a part of driving energy generated from the wire 321 as elastic energy when the driving member 311 is driven in the first direction in which the driving addition is small by the wire 321. On the other hand, when the driving member is driven in the second direction with a large driving load by the wire 322, the stored elastic energy is released as a part of the driving energy of the driving member 311. As a result, the stress generated by energizing the wire 321 is reduced by the force of the tension spring 325, so that the repeated life can be extended.

Patent Document 5 discloses a lens driving device using an SMA that can accurately stop a lens group such as a camera at a desired position. The lens driving device described in Patent Document 5 determines an energization amount necessary for moving the lens group to a desired position based on the energization amount at the time when the lens group starts to move, and the determined energization amount. Is applied to SMA to accurately stop the lens group at a desired position.
JP 60-257781 A (published on December 19, 1985) JP 2000-56208 A (published February 25, 2000) JP 2003-344903 A (published on December 3, 2003) JP 2006-38931 A (published February 9, 2006) JP 2007-57581 A (published March 8, 2007)

  Generally, a shape memory alloy (SMA) has a characteristic curve as shown in FIG. FIG. 5B is a diagram showing a characteristic curve representing the characteristics of strain with respect to temperature in SMA. As shown in FIG. 5B, the SMA characteristic curve includes a portion where the characteristic curve represented by the L1 and L3 regions is slow and a portion where the characteristic curve represented by the L2 region is steep.

  The conventional actuator devices disclosed in Patent Documents 1 to 4 operate the driven member at high speed by utilizing the fact that the characteristic curve has a portion that changes sharply depending on the SMA applied current and temperature. The fact that the driven member can be operated at a high speed is very suitable, for example, in a bipolar operation such as On / Off switching and open / close switching. That is, the actuator device using SMA has an advantage in that a portion having a steep characteristic curve, that is, a region where the driven member can be moved at high speed can be used.

  However, when the driven member is moved with high accuracy by the actuator device using SMA, the presence of this steep portion becomes a problem. That is, in the portion where the displacement of the characteristic curve represented by the L2 region shown in FIG. 5B is steep, the applied current and the surrounding temperature fluctuate and appear in the displacement of the SMA. Therefore, when the driven member is moved to a desired moving position with high positional accuracy, a slight difference in applied current and a difference in temperature are determined by determining the amount of displacement of the SMA using a steep portion of the characteristic curve. Therefore, the displacement amount of the driven member is greatly different. Therefore, it is difficult to completely move the lens group (driven member) to a desired position in the configuration of the lens driving device described in Patent Document 5 in which the energization amount is simply determined based on a desired movement value. Have a problem.

  This problem can be dealt with by combining the actuator device with a highly accurate current control system or a control system that can quickly feed back temperature fluctuations, but such a control system becomes very complex and long. There are problems in terms of cost and efficiency.

  The present invention has been made in view of the above-described problems, and a main object thereof is to provide a drive control device that controls driving of a plurality of drive members made of SMA so as to drive a driven member with high positional accuracy. To do.

In order to solve the above problems, a drive control device according to the present invention provides
A drive control device that controls driving of a driven member by an actuator including a plurality of driving members made of a shape memory alloy connected in series with each other via an insulating portion,
The total value of the strain amount for each driving member is equal to the displacement amount of the driven member, and the strain amount for each driving member is equal to or lower than the reverse transformation start temperature of the shape memory alloy used, or A strain amount setting means for setting a strain amount for each of the drive members so that the strain amount is equal to or higher than the martensite transformation start temperature;
An applied current value determining means for determining a current value to be applied to each of the driving members based on each strain amount set in the strain amount setting means;
Current applying means for applying a current of the current value determined by the applied current value determining means to each of the driving members;
It is characterized by having.

  The strain amount setting means in the drive control device according to the present invention is configured so that the strain amount of each driving member is equal to the displacement amount of the driven member, and the strain amount is equal to or lower than the reverse transformation start temperature of the shape memory alloy to be used. Alternatively, the strain amount of each drive member is set so that the strain amount is equal to or higher than the martensite transformation start temperature.

  According to the above configuration, the amount of strain of each driving member is equal to the amount of displacement of the driven member by using the amount of strain in the slow portion without using the steep portion of the characteristic curve of the shape memory alloy used. The amount of distortion of the drive member can be set to be equal. As a result, it is possible to prevent the amount of distortion of the driving member from greatly changing due to a slight temperature change with respect to the driving member, and therefore, between the total value of the amount of distortion of each driving member and the amount of displacement of the driven member. The error can be made very small. That is, there is an effect that the accuracy of alignment when the driven member is moved can be extremely increased.

  In the drive control device according to the present invention, each of the drive members refers to a strain amount setting table in which the strain amount setting means records the displacement amount and the strain amount for each of the drive members in association with each other. It is preferable to determine the amount of distortion.

  According to the above configuration, it is possible to easily and quickly set the distortion amount of each driving member so as to obtain a desired displacement amount of the driven member. As a result, the time required for driving the driven member to a desired position can be shortened.

  In the drive control device according to the present invention, the applied current value determining means may further apply the applied current to each of the drive members with reference to an applied voltage determination table in which the distortion amount and the applied current value are recorded in association with each other. The applied current value to be determined is preferably determined.

  According to the above configuration, it is possible to easily and quickly set a current value that provides a desired amount of distortion of each driving member. As a result, the time required for driving the driven member to a desired position can be further shortened.

  The drive control device according to the present invention further includes a movement value of the driven member with reference to the position of the driven member in a state where all the driving members are contracted or extended to the maximum, and the driven member It is preferable to further include a displacement amount setting unit that refers to parameter data associated with a physical parameter and sets the movement value that is a predetermined physical parameter as the displacement amount.

According to the said structure, there exists an effect which can recognize the displacement amount of a to-be-driven member automatically in a drive control apparatus. That is, even when the desired position of the driven member changes for each operation, it is necessary for the operator (operator) of the device equipped with the actuator controlled by the drive control device to grasp the change. The effect that can be omitted,
The drive control device according to the present invention further includes position recognition means for calculating the position of the driven member based on the resistance value for each driving member, and the movement value based on the position of the driven member. Movement value calculation means for calculating and parameter data creation means for recording the calculated movement value in association with the physical parameter for each movement value while scanning the driven member within the movable range of the driven member. And are preferably further provided.

  According to the above configuration, even when the type of the driven member and / or at least one of the driving members is changed, the parameter data in which the movement value of the new driven member is associated with the physical parameter is created. be able to. Thus, even when at least one of the driven member and the driving member is changed, the driven member can be driven with high positional accuracy.

  In the drive control apparatus according to the present invention, it is preferable that the displacement amount determination unit corrects the movement value in the parameter data to a difference value from the position calculated by the position recognition unit.

  According to the above configuration, the movement value calculated with the initial position (reference position) of the driven member as 0 can be corrected to a value with the current position when starting the movement of the driven member as 0. . Thereby, when setting the amount of displacement, the operation of returning the position of the driven member to the initial position can be made unnecessary. Therefore, there is an effect that the time required for the movement of the driven member can be shortened.

  The drive control apparatus according to the present invention further includes a strain amount determination unit that determines whether or not the strain amount for each of the driving members is the same as the strain amount set in the strain amount setting unit. When the determination by the distortion amount determination unit is negative, it is preferable that the applied current determination unit corrects the current value applied to the driving member so that the distortion amount set by the distortion amount setting unit is obtained.

  According to the above configuration, for example, even when the amount of distortion of the driving member changes due to an external impact or a temperature change in the surrounding environment of the driving member, the current value is set so that the set amount of distortion is obtained. Can be corrected. As a result, the driven member can be held at a desired position until an instruction to drive the driven member is given.

  Note that an actuator driven and controlled by the drive control device described above and a camera module including the actuator are also included in the scope of the present invention.

  In the drive control device according to the present invention, the strain amount setting means is configured such that the total strain amount for each drive member is equal to the displacement amount of the driven member, and the strain amount for each drive member is the reverse of the shape memory alloy used. The strain amount for each drive member is set so that the strain amount is equal to or lower than the transformation start temperature, or the strain amount is equal to or higher than the martensite transformation start temperature.

  As a result, the amount of distortion of the driving member does not change greatly due to a slight temperature change with respect to the driving member, so the error between the total amount of distortion of each driving member and the amount of displacement of the driven member is very small. can do. That is, there is an effect that the accuracy of alignment when the driven member is moved can be extremely increased.

Embodiment 1
A drive control apparatus according to the present invention will be described below with reference to FIGS. The actuator whose driving is controlled by the drive control device according to the present invention is not particularly limited as long as it includes a plurality of driving members made of SMA. In the present embodiment, in order to facilitate understanding of the invention, a case of controlling an actuator mounted on a camera module will be described as an example. Therefore, the driven member according to the present embodiment is a lens group.

(Configuration of drive control device 1)
The configuration of the drive control apparatus according to the present invention will be described below with reference to FIG.

  FIG. 1 is a block diagram showing a configuration of a drive control apparatus 1 according to the present invention. In FIG. 1, the camera module 100 is not included in the drive control device 1, but is illustrated in FIG. 1 for convenience. As shown in FIG. 1, the drive control device 1 includes a displacement amount setting unit 10, a distortion amount setting unit 11, an applied current determination unit 12, a storage unit 13, a control unit (position recognition unit, movement value calculation unit, distortion amount determination). Means) 14, a parameter data generation unit 15, and a power source (current application means) 16. Each member will be described below.

(Displacement amount setting unit 10)
The displacement amount setting unit 10 is for setting an amount indicating how much the driven member is moved in which direction, that is, a displacement amount. The displacement amount may be set from an external device or may be calculated by the drive control device 1. The case where the displacement amount is calculated in the drive control device 1 will be described below.

(Distortion amount setting unit 11)
The strain amount setting unit 11 sets the strain amount of a driving member made of a shape memory alloy (hereinafter also referred to as SMA) so as to drive the driven member by the displacement amount set by the displacement amount setting unit 10. Is. The strain amount setting unit 11 sets the strain amount so that the displacement amount set in the displacement amount setting unit 10 is equal to the total value of the strain amount for each driving member. Further, in setting the strain amount, the strain amount for each driving member is set so as to be a strain amount equal to or lower than the reverse transformation start temperature of the SMA material to be used or a strain amount equal to or higher than the martensitic transformation start temperature. A detailed method for setting the distortion amount will be described below.

(Applied current determination unit 12)
The applied current determination unit 12 is for determining a current value to be applied to each driving member so that the strain amount set in the strain amount setting unit 11 is obtained. A detailed method for determining the current value to be applied will be described below.

(Storage unit 13)
The storage unit 13 includes a nonvolatile memory in which stored information does not disappear even when the power is turned off, and a volatile memory in which stored information disappears when the power is turned off. The non-volatile memory stores, for example, a characteristic curve indicating the characteristics of the strain amount with respect to temperature in the SMA material to be used, and the volatile memory includes the displacement amount setting unit 10, the strain amount setting unit 11, and the applied current determining unit 12. The displacement amount, distortion amount, current value, and the like set in step 1 are stored.

(Control unit 14)
The control unit 14 performs overall control of the drive control device 1 such as a current application instruction, confirmation of the position of the driven member, and calculation of a movement value. As the control unit 14, a microcomputer (microcomputer) or the like can be used. In addition to the applied current determination unit 12, the parameter data generation unit 15, and the power source 16, the control unit 14 is connected to various mechanisms necessary for drive control.

(Parameter data generation unit 15)
The parameter data generation unit 15 is for creating parameter data used when the displacement amount setting unit 10 sets the displacement amount. A detailed method of creating parameter data will be described below.

(Power supply 16)
The power source 16 is for applying a current having a current value determined by the applied current determining unit 12 to the driving member.

(Configuration of camera module 100)
Here, in the present embodiment, the configuration of a camera module including an actuator whose drive is controlled by the drive control device 1 will be described below with reference to FIGS. In the present embodiment, the drive members and the like in the following description refer to those provided in the camera module shown in FIGS. 2A to 2D are views showing the configuration of the camera module 100, FIG. 2A is a perspective view of the camera module 100, and FIG. 2B is a view showing each member constituting the camera module 100. FIG. (C) is a cross-sectional view of the camera module 100 taken along the line AA ′, and (d) is a cross-sectional view of the camera module 100 taken along the line BB ′.

  As shown in FIG. 2A, the camera module 100 includes a light receiving element 107 and a lens unit 120. Further, as shown in FIG. 2B, the lens unit 120 includes an SMA member 121, a driven member 123, a pressurizing member 124, a support mechanism 125, and a base member 126. As shown in FIG. 2C, the SMA member 121 and the pressurizing member 124 are collectively referred to as an actuator 127.

(Light receiving member 107)
The light receiving element 107 is an element that receives incident light that has entered the lens unit 120 and passed through the driven member 123. Therefore, the light receiving element 107 is disposed on the surface opposite to the light receiving surface of the lens unit 120. Examples of the light receiving element 107 include a charge coupled device (CCD) and a complementary metal oxide semiconductor (CMOS). Further, the light receiving element 107 may not only simply receive the formed image but also analyze the optical physical parameter through the processing of the received light signal. The physical parameter is data derived from an image signal such as a spot diameter of the driven member 123, for example.

(SMA member 121)
The SMA member 121 is for driving the driven member 123, and includes driving members 101 a and 101 b and a connecting jig (insulating portion) 103. As shown in FIGS. 2C and 2D, the driving members 101a and 101b are arranged to apply stress to the driven member 123 in the same direction on the same axis. Of the end portions of the drive member 101 a, the end portions that are not connected to the connection jig 103 are fixed to the connection point P <b> 1 of the base member 126. Of the end portions of the driving member 101 b, the end portions that are not connected to the connection jig 103 are fixed to the driven member 123.

  The drive members 101 a and 101 b are drive members made of a shape memory alloy, and are provided in series with each other via the connection jig 103. That is, the drive member 101a and the drive member 101b are connected so as to be electrically insulated and thermally independent. FIGS. 3A to 3C are diagrams showing specific examples of connection of the drive members 101a and 101b.

  FIG. 3A shows a configuration in which the drive members 101a and 101b are fused and connected to a metal such as solder at metal contacts provided at both ends of a connecting jig 103 made of an insulator. A lead wire 104 is connected to the fusion point. FIG. 3B shows a configuration in which the crimp terminal 105 obtained by crimping the end portions of the drive members 101 a and 101 b is screwed to the connection jig 103 with a screw having a lead wire 104. FIG. 3C shows a configuration in which a holding jig 106 is interposed when the driving members 101 a and 101 b are screwed to the connection jig 103 with screws having lead wires 104. . 3A to 3C only show an example of the connection between the driving member 101a and the driving member 101b, and the driving member 101a and the driving member 101b are electrically insulated from each other. And if it can connect so that it may become thermally independent, it will not be limited to the structure of Fig.3 (a)-(c).

  The shapes of the drive members 101a and 101b are not particularly limited, and materials such as a coil shape and a plate shape may be appropriately used in accordance with the purpose of the SMA member 121. In the present embodiment, the case of using a thin wire is described as an example.

(Driven member 123)
The driven member 123 is a member driven by the SMA member 121. In this embodiment, since the camera module 100 is illustrated as a specific example, the driven member 123 is a lens group including at least one lens. 2C and 2D are arrows indicating the driving direction of the driven member 123 by the SMA member 121.

(Pressure member 124)
The pressurizing member 124 is provided between the bottom surface of the base member 126 and the driven member 123. The pressurizing member 124 applies stress in the opposite direction on the same axis with respect to the stress from the drive members 101 a and 101 b in the SMA member 121. That is, by combining the SMA member 121 and the pressurizing member 124, the driven member 123 serves as an actuator 127 that can be driven in a predetermined driving direction.

  Here, the driven member 3 comes to rest at a point where stress is balanced by the driving members 101 a and 101 b and the pressurizing member 124. Therefore, the materials, lengths, and springs of the driving members 101a and 101b and the pressurizing member 124 are set so that the initial position of the driven member 3, that is, the reference position when measuring the movement value, is in a stationary state. It is preferable to set each parameter such as a constant. Note that the driving members 101a and 101b at this time are in a state of extending from the shape memorized by the pressurization from the pressurization member 124.

(Support mechanism 125 and base member 126)
The support mechanism 125 is a mechanism that guides driving of the driven member 123. Further, the base member 126 is a housing including a driven member 123, a support mechanism 125, and an actuator 127 therein, and an opening for capturing light and a driven member 123 are provided on the top and bottom surfaces thereof. Openings for allowing the light receiving element 107 to receive the passed light are respectively provided.

(Characteristics of SMA)
Next, the SMA provided in the SMA member 121 will be described below. SMA is an alloy (for example, Ni—Ti alloy) whose shape can be memorized by high-temperature treatment. That is, the shape of the SMA can be changed by changing the temperature. In the present invention, the material of the SMA used is not particularly limited, and any material can be used as long as it is a conventionally known SMA.

  The shape memory by SMA is demonstrated below with reference to Fig.4 (a)-(c). 4 (a) to 4 (c) are diagrams showing changes in the crystal structure of SMA by changing the temperature, (a) shows the crystal structure in the austenite phase, and (b) shows the martensite phase. (C) shows the crystal structure in the state of stress martensite transformation.

  When the SMA in the austenite phase (the shape memory state) shown in FIG. 4 (a) is cooled to a temperature below the transformation point, a martensite phase as shown in FIG. 4 (b) is obtained (this is called martensitic transformation). Called). SMA is usually designed to be in the martensite phase around room temperature. Then, when a load is applied in this state, as shown in FIG. 4 (c), adjacent atoms are sheared and deformed in such a way that they are bent (this is referred to as stress martensite transformation). When the stress martensitic transformed SMA is heated above the transformation point, it returns to the austenite phase (this is referred to as reverse transformation).

  Here, in SMA, the stress required for deformation at a low temperature is about 20 MPa, and the stress generated by the shape recovery at a high temperature is about 100 MPa. Therefore, a characteristic curve indicating the nature of displacement with respect to temperature in SMA is a hysteresis curve as shown in FIGS. 5 (a) and 5 (b). In FIGS. 5A and 5B, “Ms” is the martensite transformation start temperature, “Mf” is the martensite transformation end temperature, “As” is the reverse transformation start temperature, and “Af” is the reverse transformation end temperature. Represents. However, the displacement between Mf and As and between Ms and Af in the actual characteristic curve is not “0” as shown in FIG. That is, the strain amount of SMA between the above temperatures changes slowly as shown in FIG. Slow changes in the amount of strain between Mf and As and between Ms and Af in the characteristic curves are slightly different depending on the material, composition, and shape of the SMA, but are not necessarily observed in commonly used SMAs. It is done.

  Therefore, in this specification and the like, the characteristic curve changes below the reverse transformation start temperature (As) and above the martensite start temperature (Ms) are defined as “slow portions (L1 and L3, respectively)”. Yes. In addition, a change in the characteristic curve at the reverse transformation start temperature (As) or more and the martensite transformation start temperature (Ms) or less is defined as a “steep portion (L2)” of the change. More specifically, the “slow part” means a change in the characteristic curve between As and Mf and Ms and Af and below.

(Control operation of the driving cleansing device 1)
The drive control operation of the actuator 127 by the drive control device 1 will be described below with reference to FIG. FIG. 6 is a flowchart showing the drive control operation of the actuator 127 by the drive control device 1.

  When the control unit 14 receives a signal for driving the driven member 213 from an external device (not shown) (Yes in step S1), the control unit 14 causes the displacement amount setting unit 10 to set the displacement amount of the driven member 123. . That is, the displacement amount setting means 10 sets a displacement amount indicating how much the driven member 213 is moved in which direction (step S2). At this time, the displacement amount of the driven member 213 may be transmitted from an external means together with the drive signal described above, or may be calculated and set in the drive control device 1. The process for calculating the displacement amount in the drive control device 1 will be described below. The displacement amount setting means 10 sends the set displacement amount to the storage unit 13 and the distortion amount setting unit 11.

  The strain amount setting unit 11 sets the strain amount in the drive members 101a and 101b based on the displacement amount set in the displacement amount setting unit 10 (step S3). At this time, the strain amount setting unit 11 sets the total strain amount of the drive members 101a and 101b to be equal to the displacement amount, and uses each of the slow portions of the characteristic curves of the drive members 101a and 101b. Set the amount of distortion. The strain amount setting unit 11 sends the set strain amount to the storage unit 13 and the applied current determination unit 12. The applied current determination unit 12 determines a current value to be applied to the drive members 101a and 101b based on each strain amount set by the strain amount setting unit 11 (step S4). The applied current determination unit 12 sends the determined current value to the storage unit 13 and the control unit 14.

  The control unit 14 recognizes the current value determined by the applied current determination unit 12, and sends an instruction to the power source 16 to apply the determined current value to each of the drive members 101a and 101b. The power supply 16 that has received a current application instruction from the control unit 14 applies a predetermined current value to each of the drive members 101a and 101b (step S5).

  As a result, the driving members 101a and 101b expand and contract by a desired amount of distortion, and the driven member 123 is driven by a desired amount of displacement.

  The power supply 16 applies a current to the driving members 101a and 101b until the control unit 14 receives a signal for driving the driven member 213 from an external device (that is, Yes in step S1). Continue to hold the position of the driven member 123.

(Detailed setting method of displacement)
A case where the displacement amount is calculated and set in the drive control device 1 will be described below with reference to FIG. When the displacement amount is calculated and set in the drive control device 1, the displacement amount setting means 10 records the physical parameter corresponding to the movement value of the driven member as shown in FIG. Refer to the parameter data. That is, the displacement amount setting unit 10 sets a movement value at which the physical parameter of the driven member becomes a desired value as the displacement amount of the driven member. In this specification and the like, the “movement value” means how much the driven member moves with the position of the driven member in a state in which all the driving members are fully contracted or extended as a reference value (initial position). It is a value indicating whether or not

  For example, the displacement amount setting unit 10 searches for the minimum point in the function of the physical parameter corresponding to the displacement from the parameter data shown in FIG. 7, and the movement value of the value having the smallest value (that is, the minimum value) among the minimum values Z is set as the displacement amount Z of the driven member 123. The parameter data may be created in the drive control device 1 or may be stored in the storage unit 13 in advance. The case of creating parameter data will be described below.

  Further, when the displacement amount of the driven member 123 is set, a movement value from the current position of the driven member 123 to be driven may be calculated as the displacement amount. Specifically, when driving of the driven member 123 is started, the current position of the driven member 123 to which the control unit 14 is driven is calculated. Then, the displacement amount setting means 10 subtracts the current position of the driven member 123 calculated from the movement value that is the value of the desired physical parameter in the parameter data. That is, the movement value of the parameter data is corrected to the value from the calculated current position.

  Thus, by correcting the movement value calculated with the initial position (reference position) of the driven member 123 as 0, the current position when starting the movement of the driven member 123 is corrected to 0. When setting the amount of displacement, the operation of returning the position of the driven member 123 to the initial position can be made unnecessary. Therefore, the time required for the movement of the driven member 123 can be shortened.

  The parameter data shown in FIG. 7 is only an example, and is particularly limited as long as the movement value of the driven member 123 and the physical parameter in the movement value are recorded in association with each other. It is not a thing.

  As described above, the control drive device 1 can automatically set the displacement amount of the driven member 123. Thus, even when the desired position of the driven member 123 changes for each operation, it is possible to eliminate the need for the operator (operator) of the camera module 100 to grasp the change.

(How to create parameter data)
A detailed creation method when the parameter data is created in the drive control device 1 will be described below. The parameter data is created using the control unit 14 and the parameter data creation unit 15. Specifically, the control unit 14 scans the driven member 123 over the entire movable range. Simultaneously with the scanning of the driven member 123, the control unit 14 acquires the movement value of the driven member 123 and the physical parameter measured by the light receiving element 107, and sends it to the parameter creating unit 15. The parameter creation unit 15 registers the received movement value and physical parameter in association with each other, and creates parameter data. The parameter creation unit 15 stores the created parameter data in the storage unit 13.

  The parameter data may be created for each driving operation of the driven member 123, or once the parameter data is created, the parameter data stored in the storage unit 13 may be used. Good.

  Thus, even if at least one of the driven member 123 and the driving members 101a and 101b is changed by creating parameter data in the parameter data creating unit 15, the movement value and physical parameter of the driven member are changed. And new parameter data recorded in association with each other can be created. Thereby, even when at least one of the driven member 123 and the driving members 101a and 101b is changed, the driven member 123 can be driven with high positional accuracy.

(Calculation of the movement value of the driven member 123)
Here, a method for calculating the movement value of the driven member 123 calculated when creating the parameter data will be described below with reference to FIG.

  The movement value of the driven member 123 can be calculated by measuring the resistance values of the driving members 101a and 101b. The resistance values of the drive members 101a and 101b can be measured, for example, with a configuration as shown in FIG. FIG. 8 is a diagram illustrating a configuration in which the resistance values of the driving members 101 a and 101 b are measured by the driving members 101 a and 101 b themselves or the resistance 20.

  In the present embodiment, energization heating is used as a method of heating the drive members 101a and 101b. Examples of the energization method when the drive members 101a and 101b are energized and heated include voltage control and PWM (Pulse Width Modulation) control. When voltage control is used as the energization method, the voltage applied to the drive members 101a and 101b is controlled through the lead wires 104 connected to both ends of the drive members 101a and 101b, and the resistance values of the drive members 101a and 101b are set. The amount of expansion / contraction of the drive members 101a and 101b can be controlled with feedback. That is, the position of the driven member 123 can be recognized by measuring the resistance values of the driving members 101a and 101b. The voltage applied to the drive members 101 a and 101 b can be measured using the voltmeter 21. Alternatively, the voltage of the resistance element 20 connected in series to the driving members 101a and 101b may be measured, and the resistance value of the driving members 101a and 101b may be calculated a priori using the measured value. FIG. 8 only shows an example of a configuration for calculating the resistance values of the drive members 101a and 101b. In other words, the configuration is not limited to the configuration shown in FIG. 8 as long as the resistance values of the driving members 101a and 101b can be measured.

(Driving control of driven member 123 when creating parameter data)
The operation of the driven member 123 and the temperatures of the driving members 101b and 101b when creating parameter data will be described with reference to FIGS. FIGS. 9A to 9C are views showing the operation of the driven member 123 and the temperature changes of the driving members 101b and 101b in the case of creating parameter data. FIG. 9A shows the state before scanning. b) shows the end of scanning, and (c) shows the end of displacement.

  As shown in FIG. 9A, before the driven member 123 is scanned, no current is applied to either of the driving members 101a and 101b. Subsequently, the power supply 16 that has received an instruction to scan the driven member 123 from the control unit 14 applies a current to the driving member 101a.

  The drive member 101a to which the current is applied starts to contract as shown in FIG. 9B. At this time, no current is applied to the drive member 101b. The driving member 101b maintains the same length, and the driven member 123 is moved only by driving by the driving member 101a. That is, the driven member 123 is scanned only with the tensile stress generated by the contraction of the driving member 101a. At this time, the position of the driven member 123, that is, the movement value of the driven member 123 is fed back to the control unit 14 as described above. Further, the light receiving element 107 measures the spot diameter in order to search for a suitable focal position of the driven member 123, and sends the measurement result to the control unit 14.

  The parameter data creation unit 15 creates parameter data based on each data sent to the control unit 14 and stores the created parameter data in the storage unit 13. That is, there is a one-to-one correspondence between the amount of distortion of the driving member 101a and the movement value of the driven member 123. For the scanning of the driven member 123, the entire characteristic curve of the driving member 101a, that is, all the regions L1, L2, and L3 in the characteristic curve (see FIG. 5B) are used.

  In the scanning of the driven member 123, by increasing the applied voltage or current, the scanning of the driven member 123 can be performed at a high speed. The time required for scanning the driven member 123 is not generally determined because the way in which heat is transmitted depends on the shape of the SMA or the surrounding heat distribution, but is preferably on the order of about 100 ms. .

  When the scanning is completed, as described above, the displacement amount setting unit 10 refers to the parameter data and sets the movement value of the driven member 123 serving as a desired physical parameter as the displacement amount. Then, the strain amount setting unit 11 sets the strain amounts of the drive members 101a and 101b so that the displacement amount is set as described above, and the applied current determination unit 12 determines the current value as the strain amount. In this way, the driven member 123 is driven to a desired position as shown in FIG. At this time, as shown in FIG. 9C, the distortion amounts of the drive members 101a and 101b are set so as to be slow portions in the characteristic curve.

  9A to 9C illustrate the case where the driving member 101a is used for scanning the driven member 123. Of course, the driving member 101b may be used instead of the driving member 101a. Both driving members 101a and 101b may be used. When both the driving members 101a and 101b are used, the scanning speed can be further increased by using a steep portion in the characteristic curve of the driving members 101a and 101b.

  In creating parameter data, the driven member 123 does not have to scan the entire movable range. For example, when the desired physical parameter is already known, the physical parameter is measured while scanning the driven member 123, and the movement value of the driven member 123 at the time when the desired physical parameter is reached is the displacement amount. You may make it set as.

(Detailed setting of the distortion amount of the driving members 101a and 101b)
Next, a detailed method for setting each strain amount of the drive members 101a and 101b will be described below with reference to FIGS. FIG. 10 is a diagram illustrating a usage region of the driving members 101 a and 101 b with respect to the displacement amount of the driven member 123. FIG. 11 is a diagram illustrating a distortion amount setting table in which the displacement amount of the driven member 123 and the distortion amounts of the driving members 101a and 101b are registered in association with each other. In FIG. 10, for convenience, the regions in the characteristic curve of the drive member 101a are denoted by L1, L2, and L3 shown in FIG. 5B, and the regions in the characteristic curve of the drive member 101b are L1 ′, L2 ′, and L3 ′, respectively. And

For example, as shown in FIG. 10, it is possible to align the position displacement amount of the driven member 123 to desired when it is Z _1, L1 region (slow portion) of the drive member 101a only. That is, the strain amount setting unit 11 refers to the strain amount setting table shown in FIG. 11 and sets the strain amount of the drive member 101a to “a ₁ ” and the strain amount of the drive member 101b to “0”.

For example, as shown in FIG. 10, when the displacement amount of the driven member 123 is Z _2, drive member 101a, when trying to align a desired position by using only one of 101b, in the characteristic curve of the SMA It is necessary to use the L2 region (steep portion). Therefore, by using the two regions L1 and L1 ′, which are slow portions of the characteristic curves of the driving members 101a and 101b, the driven member 123 can be brought to a desired position without using the steep portions of the characteristic curves. Align. Specifically, the strain amount setting unit 11 refers to the strain amount setting table shown in FIG. 11 and sets the strain amount of the drive member 101a as “b ₁ ” and the strain amount of the drive member 101b as “b ₂ ”. To do. Of course, both “b ₁ ” and “b ₂ ” are distortion amounts of a slow portion in the SMA characteristic curve.

For example, as shown in FIG. 10, it is possible to align the position displacement amount of the driven member 123 to desired when it is Z _3, L3 region (slow portion) of the drive member 101a only. That is, the strain amount setting unit 11 refers to the strain amount setting table shown in FIG. 11 and sets the strain amount of the drive member 101a to “c ₁ ” and the strain amount of the drive member 101b to “0”.

In the case the amount of displacement of the driven member 123 is _{Z 3,} the drive member without 101a aligned in the L3 region of the drive member 101a, a slow part of 101b of the characteristic curves L1 and L1 '2 one of An area may be used. In this case, the stress in each driving member can be made smaller than when the L3 region of the driving member 101a is used. The strain amount setting table may be limited to one of the use of the L3 region of the driving member 101a or the L1 and L1 ′ regions of the driving members 101a and 101b. By setting it, it may be possible to select either case.

In the above description, the strain amount of each driving member is set using both FIGS. 10 and 11. However, when actually setting the strain amount, the strain amount is set by referring only to the strain amount setting table. What is necessary is just to set quantity. Further, in the above description, when the displacement amounts are Z ₁ and Z ₃ , the L1 and L3 regions of the driving member 101a are used. Of course, the L1 ′ and L3 ′ regions of the driving member 101b may be used. .

  As described above, in setting the strain amounts in the drive members 101a and 101b, the strain amounts of the drive members 101a and 101b can be easily and quickly set by referring to the strain amount setting table. Thereby, the time required for driving the driven member 123 to a desired position can be shortened.

(Detailed determination method of applied current)
A detailed method of determining the current value applied to the drive members 101a and 101b will be described below with reference to FIG. FIG. 12 is a diagram illustrating an applied current determination table in which the distortion amount of the driving member 101a and the current value that is the distortion amount are registered in association with each other. When the strain amount in each driving member is set in the strain amount setting means 11, the applied current determination unit 12 refers to the applied current determination table shown in FIG. 12 and determines a current value that becomes the set strain amount. .

Specifically, for example, when the strain amount of the driving member 101a is set to “a ₁ ” in the strain amount setting unit 11, the applied current determination unit 12 refers to the applied current determination table to the drive member 101a. The current value to be applied is determined as “I ₁ (t)”. Similarly, when the distortion amount of the drive member 101a is set to “b ₁ ” and “c ₁ ”, respectively, the applied current determination unit 12 applies the drive member 101a with reference to the applied current determination table. The current values are determined as “I ₂ (t)” and “I ₃ (t)”, respectively. The value of the current applied to the drive member 101b can be set similarly. Here, when the drive member 101a and the drive member 101b have the same material and shape, the current value to be applied may be determined with reference to the same applied current determination table.

  The applied current determination table is not limited to that shown in FIG. For example, it may be an applied current determination table that can simultaneously determine the current values applied to the drive members 101a and 101b. Further, the strain amount setting table and the applied current determination table may be associated with each other so that the strain amount setting and the applied current value in each driving member can be determined simultaneously.

  As described above, in setting the current value to be applied to the driving members 101a and 101b, by referring to the applied current determination table, it is possible to easily and quickly obtain a current value that provides a desired amount of distortion in the driving members 101a and 101b. Can be set to Thereby, the time required to drive the driven member 123 to a desired position can be further shortened.

(Position maintenance of driven member 123)
As described above, the power supply 16 continues to apply a current to the driving members 101 a and 101 b until the driven member 213 is driven next, and keeps the position of the driven member 123. However, for example, while the position of the driven member 123 is held, there may be a case where the amount of distortion of the driving members 101a and 101b changes due to an external impact or a temperature change of the driving members 101a and 101b. Therefore, it is preferable that the drive control device 1 performs control so as to keep the position of the driven member 123 at a position where a desired physical parameter value is obtained. Hereinafter, the position holding of the driven member 123 after the driving member 123 has been moved to a desired position will be described with reference to FIG. FIG. 13 is a flowchart showing the position holding operation of the driven member 123.

  When the movement of the driven member 123 to the desired position is completed, the control unit 14 calculates the position of the driven member 123 (step S10). At this time, the position of the driven member 123 is calculated by determining whether or not the strain amounts of the drive members 101a and 101b are the same as the set strain amount. That is, it calculates by measuring the resistance value in the drive members 101a and 101b.

  The control unit 14 determines whether or not the calculated position of the driven member 123 is a position that is a desired physical parameter (step S11). If there is no problem in the position of the driven member 123 in the determination result in the control unit 14 (Yes in step S11), the power supply 16 keeps the determined current until the next movement of the driven member 123 is instructed. The value current is continuously applied to the driving members 101a and 101b.

  In the determination result in the control unit 14, when there is a problem in the position of the driven member 123 (No in step S <b> 11), that is, when it is determined that the position of the driven member 123 is not at a position that becomes a desired physical parameter. Then, the distortion amount of the drive members 101a and 101b for setting the desired physical parameter is set, and the current value is corrected so as to be the distortion amount (step S12). Then, by applying the corrected current value to the driving members 101a and 101b, the driven member 123 is moved to a position that becomes a desired physical parameter (step S13).

  The position of the driven member 123 may be confirmed at all times or may be performed at regular intervals.

  By monitoring the position of the driven member 123 in this manner, for example, even when the distortion amount of the driving members 101a and 101b is changed due to an external impact or a temperature change of the driving members 101a and 101b, the position is set. The current can be reapplied so that the amount of distortion is obtained. Thus, the driven member 123 can be kept in a desired position until an instruction to drive the next driven member 123 is given.

(Function and effect)
The strain amount setting means 11 in the drive control device 1 according to the present invention uses the strain amount in the slow part of the characteristic curve of the shape memory alloy used in the drive members 101a and 101b, and the displacement amount of the driven member 123. The distortion amounts of the drive members 101a and 101b are set so as to be equal to. As a result, the amount of distortion of the driving members 101a and 101b does not change greatly due to a temperature change with respect to the driving members 101a and 101b, so the total amount of distortion of the driving members 101a and 101b and the amount of displacement of the driven member 123 And the error can be made very small. That is, the accuracy of alignment when moving the driven member 123 can be made extremely high.

(Modification of camera module 100)
The camera module that can be suitably used in the present embodiment is not limited to the camera module 100 shown in FIGS. For example, the camera module 100b configured as shown in FIGS. FIGS. 14A to 14C are views showing a modification of the camera module 100, FIG. 14A is a perspective view of the camera module 100b, and FIG. 14B is a cross section of the camera module 100b taken along line AA ′. It is a figure, (c) is sectional drawing of the camera module 100b in the BB 'line.

  As shown in FIGS. 14B and 14C, the SMA member 121 may be provided at a position facing the support mechanism 126. In the case of the camera module 100, the pressurizing direction of the pressurizing member 124 with respect to the driven member 123 is the tension direction. However, when the camera module 100b is arranged, the pressurizing direction is the compression direction. Further, as shown in FIG. 15, the movement direction by the SMA member 121 may be converted using a movement direction conversion mechanism 130 such as a pulley. With the configuration shown in FIG. 15, a camera module with a lower height can be obtained. Although not shown for convenience in FIGS. 14 and 15, similarly to FIGS. 2A to 2D, the configuration including the SMA member 121 and the pressurizing member 124 is an actuator 127.

  Furthermore, as shown in FIG. 16, the pressurizing member 124 may be a pressurizing member 131 made of a shape memory alloy different from the SMA used in the SMA member 121. That is, the actuator 127b includes an SMA member 121 and a pressurizing member 131 as shown in FIG. In this case, the SMA member 121 is cooled and extended, and the pressurizing member 131 is heated and contracted to drive the driven member. Therefore, the response speed can be increased as compared with the case where the pressurizing member 124 is an elastic member such as a spring. That is, the camera module 100d having higher responsiveness than the camera module 100 can be manufactured. Further, by appropriately setting the material and length of the pressurizing member 131, the pressurizing member 131 contracts the drive members 101a and 101b even when the drive members 101a and 101b try to contract due to the environmental temperature. It is possible to set so that a force can be exerted on the driven member 123 so as to cancel out. When the pressurizing member 131 is set in this way, the malfunction of the camera module 100d can be further prevented.

  In addition, as shown in FIG. 17, the SMA member 121b may be composed of three drive members 101a to 101c. In this case, the actuator 127c includes an SMA member 121b and a pressurizing member 124 as shown in FIG. Further, the driving members 101a, 101b, and 101c may be the same material and shape, or may be different.

  Further, by connecting the three drive members as shown in FIGS. 18A and 18B, the drive direction of the driven member 123b can be driven not only in the vertical direction but also in the three-dimensional direction. May be. 18A and 18B are cross-sectional views showing a driving device 150 capable of three-dimensionally driving the driven member 123b, and FIG. 18A shows a state before driving the driven member 123b. b) shows the driven member 123b after driving. Specifically, as shown in FIGS. 18A and 18B, driving members 101 b and 101 c are connected in parallel to the driven member 123 b provided on the pressurizing member 124. The drive member 101a is connected in series with the drive members 101b and 101c via the connection jig 103, and the end not connected to the connection jig 103 is connected to the base member 126b. As shown in FIG. 18B, the driven member 123b can be driven three-dimensionally by reducing the lengths of the driving member 101a and the driving member 101c while maintaining the length of the driving member 101b. it can. The drive control device 1 according to the present invention can also be suitably used for drive control of such a drive device. Although not shown for convenience, the driving members 101a, 101b, and 101c and the connecting jig 103 are SMA members 121b and the actuator 127c is also made of the SMA member 121b and the pressurizing member 124, as in FIG. .

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. Embodiments are also included in the technical scope of the present invention.

(Additional notes)
The lens unit in the camera module that can be used in the present invention can also be described as follows.

(First configuration)
A lens unit having a driven member, a fixing portion, a driving member, a support mechanism for supporting the driven member so as to be displaced in a predetermined direction, and a pressurizing member for the driving member.

(Second configuration)
A first connection point that is a connection point between the driving member and the fixed portion and a second connection point that is a connection point between the pressurizing member and the fixed portion pass through the center of gravity of the driven member. The lens unit according to the first configuration, which is on a different side with respect to a plane perpendicular to the driving direction.

(Third configuration)
A first connection point that is a connection point between the driving member and the fixed portion and a second connection point that is a connection point between the pressurizing member and the fixed portion are driven through the center of gravity of the driven member. The lens unit according to the first or second configuration, wherein the lens unit is on the same side with respect to a plane perpendicular to the direction.

(Fourth configuration)
The lens unit according to any one of the first to third configurations, wherein the pressurizing member is formed of an SMA member.

(Fifth configuration)
A part or all of the plurality of SMA members are used to drive the driven member over the entire driving range using a steep portion of the characteristic curve, and then a part of the plurality of SMA members or The lens unit according to any one of the first to fourth configurations, wherein all are used to define and hold the position of the driven member using a slow portion of the characteristic curve.

(Sixth configuration)
A part or all of the plurality of SMA members are used to drive the driven member using a steep portion of the characteristic curve, and one of the plurality of SMA members is determined when the optimum position is determined. The lens unit according to any one of the first to fifth configurations, in which the position of the driven member is defined and held by using a slow part of the characteristic curve using a part or all of the part.

(Seventh configuration)
Information on the optimum position is input from the outside, and based on the information, the position of the driven member is defined and held using the slow part of each characteristic curve in some or all of the plurality of SMA members. The lens unit according to any one of the first to sixth configurations.

  By using the drive control device according to the present invention, the driven member can be moved with high positional accuracy in the actuator including the driving member made of SMA. An actuator that can move a driven member with high positional accuracy can be suitably used for a lens unit of a small camera such as a camera mounted on a portable device.

It is a block diagram which shows the structure of the drive control apparatus which concerns on this invention. It is a figure which shows the structure of the camera module used in Embodiment 1, (a) is a perspective view of a camera module, (b) is a figure which shows each member which comprises a camera module, (c) is AA. It is sectional drawing of the camera module in line ', (d) is a sectional view of the camera module in line BB'. It is a figure which shows the specific example of the connection method which connects the drive member so that it is electrically insulated and it becomes thermally independent. It is a figure which shows the change of the crystal structure of SMA by changing temperature, (a) has shown the crystal structure in an austenite phase, (b) has shown the crystal structure in a martensite phase, (c) Indicates the crystal structure in the state of stress martensite transformation. It is a figure which shows the characteristic curve which shows the property of the displacement with respect to the temperature in SMA, (a) has shown the outline of the characteristic curve, (b) has shown the characteristic curve nearer actual. It is a flowchart which shows the drive control operation | movement of the actuator by a drive control apparatus. It is a figure which shows the specific example of the parameter data showing the physical parameter of the to-be-driven member with respect to the distortion amount of a driving member. It is a figure which shows the structure which measures the resistance value of a drive member by drive member itself or resistance. It is a figure which shows the operation | movement of a to-be-driven member and the change of the temperature of a drive member in the case of producing parameter data, (a) shows before scan, (b) shows the time of completion | finish of scanning, (c) is completion | finish of displacement Shows the time. It is a figure which shows the use area | region of each drive member with respect to the displacement amount of a to-be-driven member. It is a figure which shows the distortion amount setting table which matched and registered the displacement amount of the to-be-driven member, and the distortion amount of each drive member. It is a figure which shows the applied current determination table which matched and registered the distortion amount of the drive member, and the electric current value used as the said distortion amount. It is a flowchart which shows the position holding operation | movement of a to-be-driven member. It is a figure which shows the modification of the camera module in this embodiment, (a) is a perspective view of a camera module, (b) is sectional drawing of the camera module in AA 'line, (c) is BB'. It is sectional drawing of the camera module in a line. It is sectional drawing which shows the other modification of the camera module in this embodiment. It is sectional drawing which shows the other modification of the camera module in this embodiment. It is sectional drawing which shows the other modification of the camera module in this embodiment. It is sectional drawing which shows the drive device which can drive a to-be-driven member three-dimensionally, (a) has shown before the drive of the to-be-driven member, (b) has shown after the drive of the to-be-driven member. It is a figure which shows the actuator provided with the drive member which consists of the conventional SMA. It is a figure which shows the actuator provided with the drive member which consists of the conventional SMA.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drive control apparatus 10 Displacement amount setting part 11 Strain amount setting part 12 Applied current determination part 13 Memory | storage part 14 Control part (position recognition means, movement value calculation means, distortion amount determination means)
15 Parameter data generator 16 Power supply (current application means)
101a driving member 101b driving member 101c driving member 100 camera module 100b camera module 100c camera module 100d camera module 100e camera module 103 connecting jig (insulating part)
104 Lead wire 107 Light receiving element 120 Lens unit 121 SMA member 123 Driven member 124 Pressurizing member 125 Support mechanism 126 Base member 126b Base member 127 Actuator 127b Actuator 127c Actuator 150 Drive device

Claims (9)

A drive control device that controls driving of a driven member by an actuator including a plurality of driving members made of a shape memory alloy connected in series with each other via an insulating portion,
The total value of the strain amount for each driving member is equal to the displacement amount of the driven member, and the strain amount for each driving member is equal to or lower than the reverse transformation start temperature of the shape memory alloy used, or A strain amount setting means for setting a strain amount for each of the drive members so that the strain amount is equal to or higher than the martensite transformation start temperature;
An applied current value determining means for determining a current value to be applied to each of the driving members based on each strain amount set in the strain amount setting means;
Current applying means for applying a current of the current value determined by the applied current value determining means to each of the driving members;
A drive control device comprising:   The strain amount setting means determines the strain amount of each driving member with reference to a strain amount setting table in which the displacement amount and the strain amount for each driving member are recorded in association with each other. The drive control device according to claim 1.   The applied current value determining means determines an applied current value to be applied to each of the driving members with reference to an applied current determination table in which the distortion amount and the applied current value are recorded in association with each other. The drive control device according to claim 1 or 2.   Refer to parameter data that associates the movement value of the driven member with reference to the position of the driven member in a state where all the driving members are contracted or extended to the maximum, and the physical parameter of the driven member. 4. The drive control device according to claim 1, further comprising a displacement amount setting unit that sets the movement value that is a predetermined physical parameter as the displacement amount. 5. Position recognition means for calculating the position of the driven member based on the resistance value for each driving member;
A movement value calculating means for calculating the movement value based on the position of the driven member;
Parameter data creating means for recording the calculated movement value and the physical parameter for each movement value in association with each other while scanning the driven member within the movable range of the driven member. The drive control apparatus according to claim 4.   6. The drive control apparatus according to claim 4, wherein the displacement amount setting unit corrects the movement value in the parameter data to a difference value from the position calculated by the position recognition unit. A strain amount judging means for judging whether or not the strain amount for each driving member is the same as the strain amount set in the strain amount setting means;
If the determination is negative, the applied current determining means corrects the current value applied to the driving member so as to be the strain amount set in the strain amount setting means. The drive control apparatus according to any one of the above.   An actuator device that is drive-controlled by the drive control device according to any one of claims 1 to 7.   A camera module comprising the actuator device according to claim 8.

Images