JP4747679B2 - Drive device - Google Patents

Description

  The present invention relates to a driving technique using a shape memory alloy.

  When a shape memory alloy (Status Memory Alloy, hereinafter abbreviated as “SMA”) is subjected to an external force at a temperature below the martensite transformation start temperature and plastically deformed, it is heated to a temperature above the reverse transformation end temperature. It has a characteristic of restoring to a memorized shape (memory shape). 2. Description of the Related Art A drive device that realizes drive by configuring a drive mechanism using a shape memory alloy (SMA) having such characteristics and adjusting the amount of current that flows through the shape memory alloy (SMA) is known.

  As a technique for adjusting the energization current, a technique for determining a voltage value supplied to a shape memory alloy (SMA) or a duty ratio of a pulse voltage based on an ambient temperature measured by a temperature sensor has been proposed (Patent Literature). 1).

JP-A-11-324896

  However, in the adjustment technique of Patent Document 1 described above, even if the voltage applied to the SMA is controlled to a constant value, the actual resistance value of the shape memory alloy (SMA) for each driving device varies, and thus fluctuations in the energization current This causes overheating / insufficient heating of the SMA, resulting in a decrease in driving performance. In particular, when SMA is used as a driving member in a driving mechanism such as a camera shake correction device that requires high-precision driving, such a decrease in driving performance becomes a serious problem. In addition, as a method of making the energization amount constant, there is a method of changing the voltage value. However, this method requires a DA converter and is expensive because adjustment time is required.

  Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a technique that enables high-accuracy driving at a low cost in a driving apparatus using SMA.

In order to solve the above-mentioned problem, the invention according to claim 1 is a drive device that operates a movable part with respect to a fixed part, and applies a voltage to the shape memory alloy to drive the movable part. and means, based on the adjustment value that is previously stored in the storage unit, the shape example Bei and adjustment means for adjusting the voltage applied to the memory alloy, the adjustment value is in the production stage of the drive device, said shape A standard resistance value that is a design resistance value of the memory alloy is compared with a measured resistance value that is an actual resistance value of the shape memory alloy, and is calculated based on the comparison result and stored in the storage unit It is characterized by being.
Further, the invention according to claim 2 is a driving device for operating the movable part relative to the fixed part, the driving means for applying a voltage to the shape memory alloy to give displacement to the movable part, and the storage part Adjusting means for adjusting an applied voltage to the shape memory alloy based on an adjustment value stored in advance, and the adjustment value depends on the design of the shape memory alloy in the production stage of the driving device. A cross-sectional area is compared with a measured cross-sectional area which is an actual cross-sectional area of the shape memory alloy, calculated based on the comparison result, and stored in the storage unit.

According to a third aspect of the present invention, in the drive device according to the first or second aspect of the present invention, the adjustment value stored in the storage unit is a bias voltage applied to the shape memory alloy. , the adjusting means, before based on Kiba bias voltage, and adjusts the voltage applied to the shape memory alloy.

According to a fourth aspect of the present invention, in the drive device according to the first or second aspect of the present invention, the adjustment value stored in the storage unit is a duty ratio of a pulse voltage applied to the shape memory alloy. a is a reference duty ratio for applying a predetermined displacement, based on the previous Kimoto quasi duty ratio, and adjusting the voltage applied to the shape memory alloy.

According to a fifth aspect of the invention, in the drive device according to the first or second aspect of the invention, the adjustment value stored in the storage unit is a thinning width of a voltage applied to the shape memory alloy. there, the adjustment means, based on the previous SL during pulling width, and adjusting the voltage applied to the shape memory alloy.

According to a sixth aspect of the present invention, in the drive device according to any one of the first to fifth aspects, the drive means includes a first shape memory alloy connected to the movable portion and a second shape memory alloy. And a shape memory alloy.

Further, an invention according to claim 7, in the driving apparatus according to any one of the claims 1 to 5, wherein the drive means includes a connection shape memory alloy to said movable portion relative to the movable portion And an urging member for applying an external force.

According to an eighth aspect of the present invention, in the drive device according to any one of the first to seventh aspects of the present invention, temperature measuring means for measuring an environmental temperature, and the applied voltage is corrected based on the environmental temperature. And a correction means for performing the correction.

According to the first to eighth aspects of the invention, since the voltage applied to the shape memory alloy can be adjusted according to the measured resistance value or the measured cross-sectional area of the shape memory alloy, accurate position control is possible. As a result, driving performance is improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1. First Embodiment>
<Configuration>
FIG. 1 is a diagram showing a driving apparatus 10A according to the first embodiment of the present invention.

  As shown in FIG. 1, the drive device 10A includes a drive unit MP and a drive circuit unit CA. Hereinafter, the drive unit MP and the drive circuit unit CA will be sequentially described.

  The drive unit MP includes a movable unit 15, two wire-shaped shape memory alloys (SMA) 13 (13 a and 13 b) connected to both ends of the movable unit 15 in a push-pull arrangement, and two SMAs 13. Fixing portions 12a and 12b for fixing the end portions of the two.

  Terminal portions 11f and 14f for fixing the end portions of the two SMAs 13 are provided at both ends of the movable portion 15 and the fixing portions 12a and 12b. These terminal portions 11f and 14f have conductivity, and function as terminals when current is passed through the SMAs 13a and 13b.

  Since the SMA 13 has a predetermined resistance, when energized from the terminal portions 11f and 14f connected to both ends, the SMA 13 generates Joule heat and is heated. By heating by this energization, the SMA 13 recovers to the memorized shape, so that the movable part 15 can be driven in a certain direction (X direction). More specifically, the SMA 13 has a characteristic that when a predetermined temperature is reached by heating by energization, the SMA 13 is restored to a predetermined contracted shape (hereinafter also referred to as “memory state”) stored in advance. Thereby, in the configuration of the drive unit MP, the movable unit 15 moves in the + X direction when the SMA 13a is energized, and the movable unit 15 moves in the -X direction when the SMA 13b is energized.

  Here, the characteristics of the SMA 13 will be described in detail.

  FIG. 2 is a diagram showing the relationship between the energization current and the displacement in the SMA 13 having a designed resistance value (hereinafter also referred to as “standard resistance value”) Ro.

  As shown in FIG. 2, the amount of current in the SMA 13 increases as the applied voltage increases, and when the temperature of the SMA 13 rises, the amount of displacement in the contraction direction increases because the SMA 13 contracts to restore the memory state. On the other hand, when the amount of current decreases due to a decrease in applied voltage and the temperature of the SMA 13 decreases, the amount of displacement in the contraction direction decreases and the SMA 13 is easily deformed (soft state). The SMA 13 starts to deform in the contraction direction when the energization current reaches the current value I1, and completes the deformation when the current value I2 is reached. That is, the region from the current value I1 required to heat the SMA 13 to the austenite transformation start temperature to the current value I2 required to heat the transformation to the transformation end temperature corresponds to the transformation temperature range in which deformation occurs in the SMA 13. It becomes.

  Next, the drive circuit unit CA will be described with reference to FIG.

  FIG. 3 is a schematic diagram showing the overall operation of the driving apparatus 10A.

  The drive circuit unit CA includes a ROM 16, a control circuit 17A that sends a drive control signal to the power supply circuit 18, and a power supply circuit 18 that supplies power by applying a voltage to each SMA 13.

  As shown in FIG. 3, in the ROM 16 in the drive circuit unit CA, the resistance value of the SMA 13 actually used in the drive device 10A is measured (hereinafter also referred to as “measured resistance value”) Rx. The determined bias voltage VBx (described later) is stored in advance as an adjustment value.

  Based on the target position signal Ps representing the target displacement of the movable portion 15 and the adjustment value (bias voltage VBx) stored in the ROM 16, the control circuit 17A transfers to the SMA 13 necessary for driving the movable portion 15 to the target position. Is applied to the power supply circuit 18 as a drive control signal.

  The power supply circuit 18 is configured as a power amplifier, for example, and applies a voltage based on a drive control signal (drive current signal) from the control circuit 17A to the SMA 13.

  The target position signal Ps input to the control circuit 17A is determined by, for example, a servo calculation unit (not shown). Further, the calculation of the target position signal may use either closed loop control or open loop control, or may use other control.

<Operation>
Next, the operation of the driving apparatus 10A having the above configuration will be described.

  FIG. 4 is a diagram for explaining the operation of the driving apparatus 10A. Here, FIG. 4A shows the signal waveform of the target position, and FIG. 4B shows the waveforms Ha and Hb of the voltage applied to the SMA 13a and SMA 13b. 4A represents the amount of movement (displacement) in the + X direction with Pi = 0 as the neutral position of the movable portion 15 shown in FIG.

  If the target position signal Ps shown in FIG. 4A is input to the control circuit 17A, the control circuit 17A generates a drive control signal for the SMA 13. Then, the power supply circuit 18 applies the voltage Ha in FIG. 4B to the SMA 13a based on the drive control signal, and applies the voltage Hb in FIG. 4B to the SMA 13b.

  In the applied voltages Ha and Hb shown in FIG. 4B, a predetermined DC component (voltage) necessary for energizing the current value in the SMA transformation temperature region of FIG. 2 is a bias voltage VBx, and the bias voltage VBx Is an analog signal that amplitudes in accordance with the target position signal Ps shown in FIG.

  More specifically, when the target position signal Ps1 for moving the movable portion 15 in the + X direction (see FIG. 1) is input in the time zone t1 in FIG. 4A, the power supply circuit 18 needs to contract. A voltage Ha1 that adds a voltage value proportional to the signal Ps1 to the bias voltage VBx is applied to the SMA 13a. On the other hand, a voltage Hb1 that subtracts a voltage value proportional to the signal Ps1 from the bias voltage VBx is applied to the SMA 13b that is expanded without the need for contraction. When the target position signal Ps2 for moving the movable portion 15 in the −X direction is input in the time zone t2, the power supply circuit 18 applies the voltage Hb2 to the contraction-side SMA 13b and the expansion-side SMA 13a. Is applied with voltage Ha2.

  Further, by determining the applied voltage with reference to the bias voltage VBx as described above, the heat radiation of the extended SMA 13 can be suppressed to the minimum necessary, and the preheating state in preparation for the next expansion / contraction operation is maintained. Can do. For this reason, since the SMA 13 on the extension side is not excessively cooled, when the next heating is performed, for example, as shown in FIG. 4A, the SMA 13b that has been extended (heat radiation) in the time zone t1 is heated in the time zone t2. Even in the case of contraction, the time lag of heating can be reduced, and the response performance of the SMA 13 can be improved.

  The bias voltage VBx of the present embodiment is individually set (adjusted) for each driving device 10A and is heated to a specific temperature within a temperature range from the transformation start temperature to the transformation end temperature of the SMA 13 in each driving device 10A. Set to the required voltage value. Hereinafter, a method for setting (adjusting) the bias voltage VBx will be described.

  FIG. 5 is a flowchart for setting the bias voltage VBx, FIG. 6 is a diagram showing a correspondence between the measured resistance value Rx and the bias voltage VBx, and FIG. 7 is a diagram showing a setting index for the bias voltage VBx. In addition, the adjustment process of FIG. 5 is performed as a part of production process of 10 A of drive devices, for example.

  First, in step S11, the resistance value (measurement resistance value) Rx of the shape memory alloy (SMA) 13 actually employed in the driving device 10A is measured.

  Next, in step S12, a bias voltage VBx with respect to the measured resistance value Rx is calculated. Specifically, the bias voltage VBx with respect to the measured resistance value Rx can be calculated by using a data table showing the relationship between the measured resistance value Rx and the bias voltage VBx as shown in FIG. Note that the data table shown in FIG. 6 conforms to the setting index of FIG. Specifically, when the measured resistance value Rx is larger than the standard resistance value Ro (for example, Rx = R1> Ro), the bias voltage VBx is larger than the standard bias voltage (standard value of the bias voltage) VBo (VBx = VB1). ). On the other hand, when the measured resistance value Rx is smaller than the standard resistance value Ro (for example, Rx = R10 <Ro), the bias voltage VBx is set to a value smaller than the standard bias voltage VBo (VBx = VB10).

  In step S13, the calculated bias voltage VBx is stored in the ROM 16.

  Then, each driving device 10A determines the voltage to be applied to the SMA 13 based on the bias voltage VBx and the target position signal Ps in the control circuit 17A, and applies the applied voltages Ha and Hb as shown in FIG. By applying to the SMAs 13a and 13b, drive control corresponding to the target position signal Ps is realized.

  The setting of the bias voltage VBx described above may be performed automatically using a computer or the like, or may be performed by a person.

  Here, if a fixed value is used as the bias voltage VBx, when the actual resistance value Rx is smaller than the standard resistance value Ro, an excessive current flows through the SMA 13 and the SMA 13 may be overheated. is there. On the other hand, when the actual resistance value Rx is larger than the standard resistance value Ro, the SMA 13 may be underheated because only a small current flows through the SMA 13. As described above, the SMA 13 may be overheated / underheated due to fluctuations in the energization current caused by the variation in resistance value.

  On the other hand, according to the operation of the above-described embodiment, it is possible to adjust the applied voltage by setting individual bias voltage VBx (adjustment value) for each driving device 10A (optimization of bias voltage VBx), and resistance Since overheating / insufficiency of heating of the SMA 13 caused by fluctuations in the energization current due to variations in values can be prevented, accurate position control is possible and driving performance is improved.

<2. Second Embodiment>
Next, a second embodiment of the present invention will be described. In the first embodiment, an analog signal voltage based on the bias voltage VBx is applied to the SMA 13 as a drive voltage. However, in the second embodiment, pulse width modulation (hereinafter referred to as “PWM”) is applied. A pulse signal controlled by a method (abbreviated) is applied to the SMA 13 as a drive voltage.

  The drive device 10B according to the second embodiment of the present invention has the same configuration as the drive device 10A of the first embodiment shown in FIG. 1, but the configuration of the drive circuit unit CB is different. That is, the drive circuit unit CB includes a control circuit 17B that outputs a drive control signal for generating a pulse signal (voltage) controlled by the PWM method to the power supply circuit 18.

  Next, the operation of the driving device 10B having the above configuration will be described. In the following description, differences from the first embodiment will be mainly described, and common portions will be denoted by the same reference numerals and description thereof will be omitted.

  FIG. 8 is a diagram for explaining the operation of the driving device 10B. Here, FIG. 8A shows a waveform Ma of the applied voltage to the SMA 13a, and FIG. 8B shows a waveform Hb of the applied voltage to the SMA 13b.

  In the drive circuit unit CB of the second embodiment, a pulse signal (voltage) controlled by the PWM method is generated as described above and applied to the SMA 13. Here, the input power to the SMA 13 can be increased or decreased by increasing or decreasing the average voltage of the pulse signal. Therefore, if the duty ratio of each pulse signal with respect to the SMAs 13a and 13b is adjusted to increase or decrease, the amount of heating and thus the amount of displacement can be controlled. The carrier frequency of the pulse signal is set to a sufficiently high frequency (for example, 1 kHz or more) with respect to the response of the SMA 13, thereby ignoring the influence of the drive error caused by the operation of the SMA 13 following the pulse signal itself. It can be suppressed to a possible level. Below, operation | movement of the drive device 10B is demonstrated.

  In the driving device 10B that uses a pulse signal controlled by the PWM method as a driving voltage, the target position signal is adjusted by increasing or decreasing the duty ratio of the pulse voltage applied to the SMAs 13a and 13b with reference to a reference duty ratio Dax (described later). Driving according to Ps is possible.

  Specifically, as in the time zone KT1 shown in FIG. 8, the pulse voltage Ma1 and the pulse voltage Mb1 having the reference duty ratio Dax (here, Dax = a1 / KT1 = b1 / KT1) are SMA 13a and SMA 13b, respectively. 4 is applied to the movable portion 15 at a target position Pi = 0 in FIG.

  Further, when the movable part 15 is driven in the −X direction (FIG. 1), pulse voltages Ma2 and Mb2 as shown in the time zone KT2 are continuously applied to the SMAs 13a and 13b, respectively. More specifically, the pulse voltage Mb2 applied to the SMA 13b has a duty ratio (b2 / b) obtained by adding a duty ratio having a magnitude corresponding to the target position in the −X direction to the reference duty ratio Dax in the pulse voltage Mb1. The pulse voltage has KT2). On the other hand, the pulse voltage Ma2 applied to the SMA 13a is set by decreasing the voltage on (ON) time a2.

  Further, when the movable part 15 is driven in the + X direction (FIG. 1), pulse voltages Ma3 and Mb3 as shown in the time zone KT3 are continuously applied to the SMAs 13a and 13b, respectively. More specifically, the pulse voltage Ma3 applied to the SMA 13a has a duty ratio (a3 / KT3) obtained by adding a duty ratio having a magnitude corresponding to the target position in the + X direction to the reference duty ratio Dax in the pulse voltage Ma1. ). On the other hand, the pulse voltage Mb3 applied to the SMA 13b is set by decreasing the voltage on (ON) time b3.

  The duty ratio Dax of the pulse signal Ma1 (or Mb1) that gives the displacement Pi = 0 as described above corresponds to the bias voltage VBx in the first embodiment. In this application, the duty ratio Dax in a pulse signal (for example, the above-mentioned pulse signal Ma1 or Mb2) for giving a predetermined reference displacement (for example, Pi = 0) is referred to as a “reference duty ratio”.

  By the way, in the control operation as described above, if a fixed value is used as the reference duty ratio Dax, overheating / insufficiency of heating of the SMA 13 occurs due to fluctuations in the energization current caused by variations in the resistance value of the SMA 13. There is.

  Therefore, in this embodiment, even in the drive device 10B that employs a drive method using PWM control, adjustment equivalent to the optimization of the bias voltage VBx described in the first embodiment is performed for each drive device. Specifically, the voltage applied to the SMA 13 is adjusted by adjusting the reference duty ratio Dax according to the measured resistance value Rx. Hereinafter, a method for setting (adjusting) the reference duty ratio Dax in pulse driving using PWM control will be described.

  FIG. 9 is a flowchart for setting the reference duty ratio Dax, FIG. 10 is a view showing the correspondence between the measured resistance value Rx and the reference duty ratio Dax, and FIG. 11 is a view showing a setting index for the reference duty ratio Dax. It is.

  First, in step S21, the resistance value (measurement resistance value) Rx of the shape memory alloy (SMA) 13 employed in the driving device 10B is measured.

  Next, in step S22, a reference duty ratio Dax with respect to the measured resistance value Rx is calculated. Specifically, the reference duty ratio Dax with respect to the measured resistance value Rx can be calculated by using a data table showing the relationship between the measured resistance value Rx and the reference duty ratio Dax as shown in FIG. Note that the data table shown in FIG. 10 conforms to the setting index of FIG. Specifically, when the measured resistance value Rx is larger than the standard resistance value Ro (for example, Rx = R1> Ro), the reference duty ratio Dax is larger than the standard value Dao of the reference duty ratio Dax (Dax = Da1). Set to On the other hand, when the measured resistance value Rx is smaller than the standard resistance value Ro (for example, Rx = R10 <Ro), the reference duty ratio Dax is set to a value smaller than the standard value Dao (Dax = Da10).

  Furthermore, in step S23, the calculated reference duty ratio Dax is stored in the ROM 16.

  Then, each driving device 10B determines a pulse voltage to be applied to the SMA 13 based on the reference duty ratio Dax and the target position signal Ps in the control circuit 17B, and the pulses as shown in FIGS. 8A and 8B. By applying the voltages Ma and Mb to the SMAs 13a and 13b, drive control according to the target position signal Ps is realized.

  The above-described reference duty ratio Dax may be set automatically using a computer or the like or may be set by a person.

  As described above, by setting the individual reference duty ratio Dax (adjustment value) for each driving device 10B (optimization of the reference duty ratio Dax), the applied voltage can be adjusted, and the conduction current caused by the variation in resistance value Since overheating / insufficient heating of the SMA 13 caused by the fluctuation of the SMA 13 can be prevented, accurate position control is possible and driving performance is improved.

<3. Third Embodiment>
Next, a third embodiment of the present invention will be described. In the first embodiment, the applied voltage is adjusted by adjusting the bias voltage VBx. In the third embodiment, the applied voltage is adjusted by adjusting the thinning width Wpx (described later) of the thinned applied voltage. Adjust the voltage.

  The drive device 10C according to the third embodiment of the present invention has the same configuration as the drive device 10A of the first embodiment shown in FIG. 1, but the configuration of the drive circuit unit CC is different. That is, the drive circuit unit CC includes a control circuit 17C that outputs a drive control signal for generating the thinned applied voltage to the power supply circuit 18.

  Next, the operation of the drive device 10C having the above configuration will be described. In the following description, differences from the first embodiment will be mainly described, and common portions will be denoted by the same reference numerals and description thereof will be omitted.

  FIG. 12 is a diagram for explaining the operation of the drive device 10C. Here, FIG. 12A shows the thinning signal Rp, and FIGS. 12B and 12C show waveforms La and Lb of the applied voltage to the SMAs 13a and 13b, respectively.

  In the drive circuit unit CC of the third embodiment, applied voltages La and Lb shown in FIGS. 12B and 12C are generated in accordance with the thinning signal Rp shown in FIG. Specifically, the voltage Ha (Hb) shown in FIG. 4B is output during the time period when the thinning signal is on (1), and the voltage is output during the time period when the thinning signal Rp is off (0). The voltages La and Lb are generated by the thinning process that does not output. Then, the driving device 10C realizes driving according to the target position signal Ps as in the first embodiment by applying the voltages La and Lb subjected to the thinning processing using the thinning signal Rp to the SMAs 13a and 13b. The thinning signal Rp has a sufficiently high frequency (for example, 1 kHz or more) with respect to the responsiveness of the SMA 13.

  Even in the driving device 10C using the above-described thinned-out voltage as the driving voltage, the adjustment equivalent to the optimization of the bias voltage VBx described in the first embodiment can be performed for each driving device. Specifically, the voltage applied to the SMA 13 can be adjusted by adjusting the thinning width Wpx of the thinning signal Rp. As described above, by changing the thinning width of the thinning signal Rp (also expressed as “thinning rate”), the applied voltage can be substantially changed.

  If a fixed value is used as the thinning width Wpx, overheating / insufficient heating of the SMA 13 may occur due to fluctuations in the energization current caused by variations in the resistance value of the SMA 13. On the other hand, if the method of the third embodiment is used, the applied voltage can be adjusted appropriately, so that overheating / insufficient heating of the SMA 13 caused by fluctuations in the energization current due to variations in resistance value is prevented. be able to. Therefore, accurate position control is possible and driving performance can be improved.

  Hereinafter, a method for setting (adjusting) the thinning width Wpx in driving using the thinned voltage will be described.

  13 is a flowchart for setting the thinning width Wpx, FIG. 14 is a diagram showing the correspondence between the measured resistance value Rx and the thinning width Wpx, and FIG. 15 is a diagram showing a setting index for the thinning width Wpx.

  First, in step S31, the resistance value (measurement resistance value) Rx of the shape memory alloy (SMA) 13 employed in the driving device 10C when the driving device 10C is configured is measured.

  Next, in step S32, a thinning width Wpx for the measured resistance value Rx is calculated. Specifically, the thinning width Wpx with respect to the measured resistance value Rx can be calculated by using a data table showing the relationship between the measured resistance value Rx and the thinning width Wpx as shown in FIG. Note that the data table shown in FIG. 14 conforms to the setting index of FIG. Specifically, when the measured resistance value Rx is larger than the standard resistance value Ro (for example, Rx = R1> Ro), the thinning width Wpx is smaller than the standard thinning width (standard value of the thinning width) Wpo (Wpx = Wp10). ). On the other hand, when the measured resistance value Rx is smaller than the standard resistance value Ro (for example, Rx = R10 <Ro), the thinning width Wpx is set to a value larger than the standard thinning width Wpo (Wpx = Wp1).

  Further, in step S33, the calculated thinning width Wpx is stored in the ROM 16.

  Then, each driving device 10C determines a voltage to be applied to the SMA 13 based on the thinning width Wpx and the target position signal Ps in the control circuit 17C, and the voltage La, as shown in FIGS. By applying Lb to the SMAs 13a and 13b, drive control corresponding to the target position signal Ps is realized.

  Note that the setting of the thinning width Wpx described above may be performed automatically using a computer or the like, or may be performed by a person.

  As described above, by setting the individual thinning width Wpx (adjustment value) for each driving device 10C (optimization of the thinning width Wpx), it is possible to adjust the applied voltage, and fluctuations in the energization current due to variations in resistance values. As a result, it is possible to prevent overheating / insufficiency of heating of the SMA 13, thereby enabling accurate position control and improving driving performance.

<4. Modification>
As mentioned above, although embodiment of this invention was described, this invention is not limited to the content demonstrated above.

  For example, in each of the above embodiments, the applied voltage is determined based on the measured resistance value Rx, and the determined voltage is applied to the SMA 13 as it is. However, the present invention is not limited to this. Specifically, after determining the applied voltage, the applied voltage may be corrected based on the ambient temperature (environmental temperature) of the shape memory alloy. Hereinafter, this will be briefly described with reference to FIG.

  FIG. 16 is a diagram showing a correction coefficient K with respect to the ambient temperature T when the correction coefficient at the standard temperature t1 is 1. For example, when driving in the state of the ambient temperature t2, a value obtained by multiplying the determined applied voltage by the correction coefficient k2 is applied to the SMA 13. According to this, it becomes possible to set an appropriate applied voltage in consideration of the ambient temperature, and the driving performance is improved. The ambient temperature T may be obtained from a temperature sensor or the like installed in the drive unit MP.

  In each of the above embodiments, when the drive device 10A (10B, 10C) is configured, the measurement resistance value Rx of the shape memory alloy (SMA) 13 employed in the drive device 10A (10B, 10C) is measured. And although the voltage applied to SMA13 is determined based on the said measured resistance value Rx, it is not limited to this. Specifically, the cross-sectional area Sx of the SMA 13 employed in the driving device 10A (10B, 10C) is measured, and a voltage to be applied to the SMA 13 is determined based on the measured cross-sectional area (also referred to as a measured cross-sectional area) Sx. You may do it.

  Further, in the driving devices 10A (10B, 10C) of the above-described embodiments, the configuration is such that the expansion / contraction direction of the SMA 13 and the movement direction of the movable portion 15 coincide (FIG. 1), but is not limited thereto. For example, like the driving device 20 shown in FIG. 17, the movable portion 15 may rotate about the fulcrum Q by expansion and contraction of the two SMAs 13.

  Further, it is not essential to have two SMAs 13 in the movable part 15 as in the driving device shown in FIGS. 1 and 17, and one SMA 13 is replaced with an elastic body BN such as a spring (FIGS. 18 and 18). 19). In such a configuration, the displacement control of the movable portion 15 can be performed by driving only one SMA 13.

It is a figure which shows the drive device which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship between the energization current and displacement in SMA which has a standard resistance value. It is a schematic diagram which shows the whole operation | movement of the drive device which concerns on 1st Embodiment. It is a figure for demonstrating operation | movement of the drive device which concerns on 1st Embodiment. It is a setting flowchart of a bias voltage. It is a figure which shows a response | compatibility with a measured resistance value and a bias voltage. It is a figure which shows the setting parameter | index of a bias voltage. It is a figure for demonstrating operation | movement of the drive device which concerns on 2nd Embodiment. It is a setting flowchart of a reference duty ratio. It is a figure which shows a response | compatibility with a measured resistance value and a reference | standard duty ratio. It is a figure which shows the setting parameter | index of a reference | standard duty ratio. It is a figure for demonstrating operation | movement of the drive device which concerns on 3rd Embodiment. It is a setting flowchart of a thinning width. It is a figure which shows a response | compatibility with a measured resistance value and a thinning width. It is a figure which shows the setting parameter | index of a thinning width. It is a figure which shows the correction coefficient with respect to ambient temperature. It is a figure which shows the drive device which concerns on the modification of this invention. It is a figure which shows the drive device which concerns on the modification of this invention. It is a figure which shows the drive device which concerns on the modification of this invention.

Explanation of symbols

13 SMA
15 Movable part 16 Power supply circuit 17 Control circuit 18 ROM
BN elastic body Q fulcrum

Claims (8)

A drive device for operating the movable part relative to the fixed part,
Driving means for applying a voltage to the shape memory alloy to give displacement to the movable part;
An adjusting means for adjusting an applied voltage to the shape memory alloy based on an adjustment value stored in advance in the storage unit ;
Bei to give a,
The adjustment value is a comparison between a standard resistance value that is a design resistance value of the shape memory alloy and a measured resistance value that is an actual resistance value of the shape memory alloy in the production stage of the drive device. A driving device calculated based on a result and stored in the storage unit.   A drive device for operating the movable part relative to the fixed part,
  Driving means for applying a voltage to the shape memory alloy to give displacement to the movable part;
  An adjusting means for adjusting an applied voltage to the shape memory alloy based on an adjustment value stored in advance in the storage unit;
With
  The adjustment value is calculated based on a comparison result by comparing a design cross-sectional area of the shape memory alloy with a measured cross-sectional area that is an actual cross-sectional area of the shape memory alloy in the production stage of the driving device. The drive device is stored in the storage unit.   The drive device according to claim 1 or 2,
  The adjustment value stored in the storage unit is a bias voltage applied to the shape memory alloy,
  The adjustment device adjusts a voltage applied to the shape memory alloy based on the bias voltage.   The drive device according to claim 1 or 2,
  The adjustment value stored in the storage unit is a duty ratio of a pulse voltage applied to the shape memory alloy and is a reference duty ratio for applying a predetermined displacement,
  The adjusting device adjusts the voltage applied to the shape memory alloy based on the reference duty ratio.   The drive device according to claim 1 or 2,
  The adjustment value stored in the storage unit is a thinning width of the voltage applied to the shape memory alloy,
  The adjusting device adjusts the voltage applied to the shape memory alloy based on the thinning width.   The drive device according to any one of claims 1 to 5,
  The driving device includes a first shape memory alloy and a second shape memory alloy connected to the movable portion.   The drive device according to any one of claims 1 to 5,
  The driving device includes a shape memory alloy connected to the movable portion and a biasing member that applies an external force to the movable portion.   The drive device according to any one of claims 1 to 7,
  A temperature measuring means for measuring the environmental temperature;
  Correction means for correcting the applied voltage based on the environmental temperature;
A drive device further comprising:

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