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WO2012093567A1 - Dispositif de commande d'actionneur en alliage à mémoire de forme et unité d'entraînement à composant optique - Google Patents

Dispositif de commande d'actionneur en alliage à mémoire de forme et unité d'entraînement à composant optique Download PDF

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Publication number
WO2012093567A1
WO2012093567A1 PCT/JP2011/079000 JP2011079000W WO2012093567A1 WO 2012093567 A1 WO2012093567 A1 WO 2012093567A1 JP 2011079000 W JP2011079000 W JP 2011079000W WO 2012093567 A1 WO2012093567 A1 WO 2012093567A1
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WIPO (PCT)
Prior art keywords
memory alloy
target position
control device
shape memory
sma
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/JP2011/079000
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English (en)
Japanese (ja)
Inventor
泰啓 本多
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Konica Minolta Opto Inc
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Konica Minolta Opto Inc
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Publication date
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Publication of WO2012093567A1 publication Critical patent/WO2012093567A1/fr
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
    • G02B7/08—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification adapted to co-operate with a remote control mechanism
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
    • F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
    • F03G7/06—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like
    • F03G7/061—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like characterised by the actuating element
    • F03G7/0614—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like characterised by the actuating element using shape memory elements
    • F03G7/06143—Wires
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/003—Alignment of optical elements
    • G02B7/005—Motorised alignment
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/023—Mountings, adjusting means, or light-tight connections, for optical elements for lenses permitting adjustment
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/04—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification
    • G02B7/10—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification by relative axial movement of several lenses, e.g. of varifocal objective lens
    • G02B7/102—Mountings, adjusting means, or light-tight connections, for optical elements for lenses with mechanism for focusing or varying magnification by relative axial movement of several lenses, e.g. of varifocal objective lens controlled by a microcomputer

Definitions

  • the present invention relates to an actuator control device using a shape memory alloy and an optical component drive unit using the same.
  • MCUs micro-camera units
  • AF auto focus
  • Ni-Ti and other shape memory alloys are known as actuators based on deformation due to temperature changes as the driving principle. Therefore, it is considered promising for applications such as the above-mentioned MCU AF.
  • the technique disclosed in Patent Document 1 introduces a response delay correction based on the movement amount of the actuator and the drive control value. ing.
  • the technique disclosed in Patent Document 2 it is proposed to improve the positional accuracy by correcting hysteresis based on a correction value stored in advance.
  • Patent Document 1 is correction of response delay, and the adverse effect of hysteresis on position accuracy cannot be reduced.
  • correction values are stored in advance in the form of a table and the like, and control is performed while sequentially referring to the correction values. This complicates the system and measures the correction values individually, for example, for each product. This also causes an increase in manufacturing costs.
  • An object of the present invention is to provide a shape memory alloy actuator control device that reduces the influence of the dependent hysteresis and realizes accurate position control, and an optical component drive unit using the same.
  • a shape memory alloy actuator control apparatus controls an actuator including a movable mechanism that moves a target object using a shape restoring force due to a temperature change of the shape memory alloy.
  • a servo control unit that performs energization according to a command position of the movable mechanism to the shape memory alloy and performs servo control using a detection value corresponding to a resistance value of the shape memory alloy;
  • a plurality of command positions including the target position and the at least one intermediate position are set by adding at least one intermediate position between the start position and the target position of the movement of the movable mechanism, and the start point
  • the plurality of command positions are sequentially given to the servo control unit in order from the side close to the position, and the movable mechanism is divided into a plurality of stages from the start position to the target position. Characterized in that it comprises a stepwise moving section for moving the manner.
  • the shape memory alloy actuator control device is the shape memory alloy actuator control device according to the first aspect, wherein the gap between the start position and the target position is determined by the at least one intermediate position. Of a plurality of divided sections formed by division, a final divided section having the target position as an end point has the shortest width among the plurality of divided sections.
  • the shape memory alloy actuator control device is the shape memory alloy actuator control device according to the first aspect, wherein the gap between the start position and the target position is determined by the at least one intermediate position.
  • a divided section width variable setting unit that variably sets the width of at least one divided section among a plurality of divided sections formed by division according to the difference between the start point position and the target position; It is characterized by.
  • the shape memory alloy actuator control device is the shape memory alloy actuator control device according to the first or third aspect, wherein the at least one between the start point position and the target position is Of a plurality of divided sections formed by division at intermediate positions, the width of the final divided section having the target position as the end point is set as a fixed value regardless of the distance difference between the start position and the target position. It is characterized by that.
  • the shape memory alloy actuator control device is the shape memory alloy actuator control device according to any one of the first to fourth aspects, and is the first command position of the movement destination from the starting point position.
  • a single stage moving unit that moves the movable mechanism from the start point position to the target position in one stage, and a difference between the start point position and the target position is a predetermined value.
  • a selective activation unit that selectively activates the stepped moving unit when a threshold is exceeded, and selectively activates the single step moving unit when the difference is less than or equal to the threshold. It is characterized by providing.
  • the shape memory alloy actuator control device is the shape memory alloy actuator control device according to any one of the first to fifth aspects, wherein the stepwise moving unit is moved to one command position. After the movement control of the movable mechanism is performed, a settling period setting unit that starts moving the movable mechanism to the next command position after a predetermined settling period is provided.
  • the optical component driving unit includes an actuator that drives a predetermined optical component using a shape restoring force due to a temperature change of the shape memory alloy, and any one of the first to sixth aspects. And a shape memory alloy actuator control device.
  • the shape memory alloy actuator control device when the movable mechanism is moved from the start position to the target position, the movement history from the start of movement is obtained through a plurality of movement processes. The influence of the dependent hysteresis can be reduced, and accurate position control can be realized.
  • the last divided section is the shortest section among the plurality of divided sections.
  • the influence on the movement accuracy of the movable mechanism to the target position is mainly due to the hysteresis in the final divided section, and the influence of the hysteresis in the previous divided section is relatively small.
  • the width (distance) of the final divided section is shortened and the widths of the other divided sections are made longer, thereby improving the position accuracy at the target position and the total displacement time from the start position to the target position. It is possible to achieve a balance with shortening.
  • the width of at least one divided section other than the final divided section is variably set according to the difference between the starting position of the displacement of the movable mechanism and the target position.
  • the position of the final divided section is set to a fixed value, so that the moving position accuracy to the target position is increased. Can be made homogeneous.
  • the shape memory alloy actuator control device when the difference between the start position of the movable mechanism and the target position is equal to or less than a predetermined threshold value, one-step movement control is performed.
  • the difference between the starting point position and the target position is small, there is not much position error without going through the stepwise movement process, so the control time can be shortened by moving the movable mechanism directly to the target position. Can do.
  • the movement to the next command position is started after a predetermined settling period.
  • the variation in the state before stoppage of movement in the immediately preceding divided section does not affect the moving process in the next divided section, and the movement in each divided section is stabilized.
  • FIG. 1 is a plan view schematically showing a main part of a mechanism of a lens driving unit using the SMA driving device according to the present embodiment.
  • FIG. 2 is a side view showing the operation of the lens driving unit of FIG.
  • FIG. 3 is a graph showing the temperature dependence of the resistance value of SMA as a characteristic curve.
  • FIG. 4 is a graph showing the temperature dependence of the resistance value of SMA as a characteristic curve.
  • FIG. 5 is a diagram showing the lens displacement dependency of the resistance value of SMA as a characteristic curve.
  • FIG. 6 is a diagram for explaining the driving response of the SMA lens driving unit.
  • FIG. 7 is a diagram for explaining the driving response of the SMA lens driving unit.
  • FIG. 8 is a block diagram showing the configuration of the SMA actuator control device according to this embodiment.
  • FIG. 9 is a diagram for explaining the drive response of the SMA lens drive unit according to this embodiment.
  • FIG. 10 is a flowchart for explaining the operation of the SMA actuator control apparatus according to this embodiment.
  • FIG. 11 is an explanatory diagram of section division and movement process in this embodiment.
  • FIG. 12 is an explanatory diagram regarding the setting of the determination threshold in the present embodiment.
  • FIG. 1 and FIG. 2 are diagrams schematically showing a main part of a mechanism in a lens driving unit 100 configured using the SMA actuator control device according to the embodiment of the present invention.
  • FIG. 1 is a plan view (lens opening surface) viewed from the lens side
  • FIG. 2 is a side view viewed from the direction of arrow A in FIG. 2A shows a state before driving
  • FIG. 2B shows a state after driving.
  • the lens driving unit 100 is used in, for example, a small camera system incorporated in a mobile phone, and performs an AF operation using an actuator using SMA (SMA actuator) as a driving source.
  • SMA SMA actuator
  • the lens driving unit 100 mainly includes a lens unit 1 (driven object), a lever member 2 that moves the lens unit 1 in the optical axis AX direction (first axis direction), an SMA actuator 3, A base member 4, a top plate 5, parallel plate springs 6 a and 6 b, a bias spring 7, and the like are provided, and the lens unit 1 and the like are assembled to the base member 4.
  • the top plate 5 and the parallel leaf springs 6a and 6b are omitted in FIG. 1 for convenience.
  • the base member 4 is fixed to a member (for example, a mobile phone frame or a mount substrate) to which the lens driving unit 100 is attached, and is a non-moving member constituting the bottom side of the lens driving unit 100.
  • the base member 4 is formed in a square plate shape in plan view, and is entirely made of a resin material or the like.
  • the lens unit 1 has a cylindrical shape, and includes an imaging lens 10, a lens driving frame 12 that holds the imaging lens 10, and a lens barrel 14 that stores the lens driving frame 12.
  • the imaging lens 10 includes an objective lens, a focus lens, a zoom lens, and the like, and constitutes an imaging optical system for a subject image with respect to an imaging element (not shown).
  • the lens driving frame 12 is a so-called ball frame, and moves in the optical axis AX direction together with the lens barrel 14.
  • a pair of support portions 16 project from the outer peripheral edge portion of the lens drive frame 12 at the distal end on the object side with an angular difference of 180 ° in the circumferential direction.
  • the lens unit 1 is disposed on the base member 4 in a state of being inserted into an opening formed in the top plate 5.
  • the pair of support portions 16 are arranged so as to be positioned in the vicinity of the pair of diagonals of the base member 4 (see FIG. 1).
  • Parallel plate springs 6a and 6b are fixed to the base member 4 and the top plate 5, respectively, and the lens unit 1 is fixed to the parallel plate springs 6a and 6b. Accordingly, the lens unit 1 is supported so as to be displaceable with respect to the base member 4 and the like, and the degree of freedom of displacement is restricted in a direction along the optical axis AX.
  • the top plate 5 may be fixed to the base member 4 via a support column (not shown) or may be a structure integrated with the base member 4.
  • the lever member 2 applies a driving force in the direction of the optical axis AX to the lens unit 1 by engaging with the lens unit 1 via the support portion 16.
  • the lever member 2 is disposed on the side of the lens unit 1, specifically, at one corner other than the corner where the support portion 16 of the lens unit 1 is located, which is the corner of the base member 4. .
  • the lever member 2 is supported so as to be swingable about an axis that is orthogonal to the optical axis AX and extends in the direction in which the pair of support portions 16 are arranged (the vertical direction in FIG. 1).
  • the lever member 2 has an arm portion 21 and an inverted L-shape in a side view having an arm portion 21 and an extending portion 22 extending from the base end portion of the arm portion 21 in the optical axis AX direction.
  • the bent portion serving as the boundary between the arm portion 21 and the extended portion 22 is supported on the base member 4 by being supported by the tip of the support leg 8 erected on the base member 4. ing.
  • the shape of the tip of the support leg 8 (hereinafter referred to as the lever support portion 8a) is a substantially cylindrical shape extending in a direction orthogonal to the optical axis AX direction (a direction orthogonal to the paper surface of FIG. 2A).
  • the lever member 2 is supported so as to be swingable about an axis orthogonal to the optical axis AX direction with the lever support portion 8a as a fulcrum.
  • the arm portion 21 is formed in an arc shape in plan view. Specifically, as shown in FIG. 1, the lens unit 1 is bifurcated from the extended portion 22 to both sides of the lens unit 1 and extends evenly in the vicinity of the outer peripheral surface of the lens unit 1. Is formed so as to surround. The tips (both ends) of the arm portion 21 reach the positions of the support portions 16 of the lens unit 1, respectively. Then, the SMA actuator 3 is bridged over the extended portion 22, and a direction perpendicular to the optical axis AX direction (second axis direction: left-right direction in FIG. 2A) at this bridge position (referred to as the displacement input portion 2a). When the moving force F1 (see FIG. 2B) is input, the lever member 2 swings.
  • the tip of the arm portion 21 (referred to as the displacement output portion 2b) is displaced in the optical axis AX direction, and the displacement output portion 2b engages with each support portion 16 to cause the lens unit 1 to move in the optical axis AX direction.
  • a driving force is applied.
  • the SMA actuator 3 applies a moving force F1 (see FIG. 2B) to the lever member 2, and is composed of, for example, an SMA wire such as a Ni—Ti alloy, and is a linear actuator having a substantially circular cross section. is there.
  • F1 moving force
  • SMA3 SMA3
  • the SMA actuator 3 expands when applied with tension in a state where the elastic modulus is low (martensite phase) at a low temperature. When heat is applied in this extended state, the SMA actuator 3 undergoes phase transformation and has a high elastic modulus (austenite phase: It has the property of moving to the parent phase and returning to its original length from its extended state (recovering its shape).
  • the SMA actuator 3 is energized and heated to perform the above-described phase transformation (details will be described later). That is, since the SMA actuator 3 is a conductor having a finite electric resistance value, Joule heat is generated by energizing the SMA actuator 3 itself, and self-heating based on the Joule heat causes the martensite phase to change to the austenite phase. It is configured to transform. For this reason, the first electrode 30 a and the second electrode 30 b for energization heating are fixed to both ends of the SMA actuator 3. These electrodes 30 a and 30 b are fixed to predetermined electrode fixing portions provided on the base member 4.
  • the SMA actuator 3 is bridged between the electrodes 30a and 30b with a portion engaging with the extending portion 22 of the lever member 2 as a turning point.
  • a movement force F1 (see FIG. 2B) is applied to the lever member 2, and this movement force F1.
  • the lever member 2 swings.
  • the electrodes 30a and 30b are arranged in the vicinity of the support portion 16 of the lens unit 1 in the base member 4, respectively.
  • the lengths of the SMA actuator 3 from the electrodes 30a and 30b to the turn-back point are set to be equal to each other, so that the amount of expansion / contraction of the SMA actuator 3 on both sides of the displacement input portion 2a becomes equal. Rubbing between the lever member 2 and the SMA actuator 3 is prevented.
  • a V-groove 21a (corresponding to the displacement input portion 2a) is formed in the extended portion 22, and the SMA actuator 3 is bridged so as to be fitted into the V-groove 21a, whereby the lever member 2 is On the other hand, the SMA actuator 3 is stably suspended.
  • the lens unit 1 moves against the pressing force of the bias spring 7.
  • the amount of displacement of the lens unit 1 is adjusted by controlling the energizing current to the SMA actuator 3 and adjusting the amount of the moving force F1.
  • the moving force F1 disappears, and the pressing force of the bias spring 7
  • the lens unit 1 returns to the home position along the optical axis AX direction. In this way, the lens unit 1 can be displaced along the optical axis AX direction by turning on and off the SMA actuator 3, and the moving force F1 can be controlled by controlling the current supplied to the SMA actuators 3a and 3b.
  • the amount of displacement of the lens unit 1 can be adjusted by adjusting the amount of force.
  • the lens unit 1 can be favorably moved along the optical axis AX in accordance with the operation of the SMA actuator 3.
  • FIG. 3 to 5 are diagrams showing general properties of physical properties of SMA.
  • FIG. 3 is a characteristic diagram showing the relationship between the temperature and the resistance value of the SMA wire.
  • the resistance value changes in a direction opposite to that of a normal metal while being deformed in the shrinking direction due to the crystal phase transformation of SMA.
  • the resistance value increases with increasing temperature as in the case of ordinary metals, but changes from the low temperature phase (generally martensite phase) to the high temperature phase (generally austenite).
  • the wire contracts so as to have a memorized shape, and the resistance value changes in a rapidly decreasing direction. And if it exceeds Af point which complete
  • the resistance value decreases as the temperature lowers, and when the temperature falls below the Ms point at which transformation from the high temperature phase to the low temperature phase starts, the SMA As the wire expands due to the bias force, the resistance value increases rapidly as the temperature decreases. And when it becomes the temperature below the Mf point which complete
  • the characteristic curve of the SMA wire in the temperature rising process and the temperature decreasing process has hysteresis (see FIG. 3).
  • FIG. 4 is a characteristic diagram showing a temperature-resistance value relationship of SMA used for driving the AF lens in the lens driving unit 100 of the embodiment. Since the maximum extension amount of the lens is up to the macro end and no further area is used, FIG. 4 shows the curve of FIG. 3 as the operation up to the macro end, and shows the range actually used as a product.
  • the resistance value in each process is defined as follows.
  • initial resistance value Rstart refers to the resistance value in a completely radiated state before energization, that is, the resistance value when energization heating is started;
  • maximum resistance value Rmax refers to the maximum resistance value near the start of transformation to the austenite phase in the process of increasing temperature from a low temperature region;
  • displacement start resistance value Rinf refers to the resistance value when the temperature rises and the lens starts moving from the infinite end;
  • the term “macro end resistance value Rmcr” refers to the resistance value when the lens is at the macro end.
  • the shrinkage of the SMA wire starts from the temperature at which the maximum resistance value Rmax is reached, but since there is a slack of the wire and elastic deformation of each part, the lens still does not move in that state, and the stress of the SMA due to the shrinkage increases.
  • the tension at the time of constructing the wire rod is appropriately set so that the imaging lens 10 actually starts to move when the stress due to the bias spring 7 is exceeded. Accordingly, the point where the temperature further rises from the point where the maximum resistance value Rmax is reached becomes the displacement start resistance value Rinf.
  • the imaging lens 10 begins to extend from the infinite end in the macro direction, and as the temperature rises further, the resistance value R decreases as the imaging lens 10 moves in the macro direction and reaches the macro end resistance value Rmcr. On the contrary, in the process of decreasing the temperature, the resistance value R increases as the imaging lens 10 moves in an infinite direction.
  • FIG. 5 is a characteristic diagram showing the relationship between the resistance value of SMA used for the lens driving unit 100 of the embodiment and the lens displacement.
  • RT correlation (see Fig. 4): Correlation between "resistance value-temperature” (resistance value decreases with increasing temperature in the temperature range where SMA contracts), TX correlation (not shown): Correlation between “temperature and SMA expansion / contraction amount” (the higher the temperature, the larger the expansion / contraction amount),
  • RX correlation a correlation of “resistance value ⁇ SMA expansion / contraction amount (lens displacement)
  • the amount of energization to SMA 3 by feedback control is determined by comparing the target position with the current position.
  • proportional control which is a simple control method
  • the energization amount is determined so as to be proportional to the difference between the target position and the current position.
  • the resistance value R of the SMA in the temperature lowering process decreases in the region where “macro end resistance value Rmcr ⁇ displacement start resistance value Rinf”, and “displacement start resistance value Rinf ⁇ maximum resistance value Rmax ⁇ initial resistance value”. In the region that changes in the order of “Rstart”, the displacement does not move at the infinite end.
  • the RX correlation characteristic curve has hysteresis in the temperature increasing process and the temperature decreasing process (see FIG. 5). This is due to the fact that the transformation temperature of the SMA 3 has temperature hysteresis, as well as friction between the support portion 16 and the arm portion 21 in FIG. 1 and FIG. include.
  • the preconditions of the SMA actuator control device that occur with the general properties of the physical characteristics of the SMA described above will be described.
  • the SMA actuator control device when constant current driving is performed, it takes a long time for the displacement of the driven object (lens) to settle, and the displacement also changes depending on conditions such as the ambient temperature. It is premised on high-speed step drive by control.
  • the servo control is a method in which the amount of energization is feedback controlled and information is moved to a target displacement while acquiring information on the current displacement.
  • the resistance value of the SMA itself correlates with the deformation amount (expansion / contraction amount) of the SMA.
  • the resistance value of SMA is detected by using this, and the resistance value is used as displacement information of SMA.
  • FIGS. 6 and 7 are diagrams for explaining the characteristics of the drive response when the distance difference between the start point position and the target position is different in the SMA actuator control device.
  • FIG. 6 shows a small distance difference (hereinafter referred to as “small width”).
  • FIG. 7 shows the drive response when the distance difference is large (hereinafter, referred to as “significant step”).
  • FIGS. 6A and 7A are diagrams for explaining the temporal change of lens displacement, and FIGS. 6B and 7B are FIGS. 6A and 7A.
  • FIG. 6 is a diagram illustrating a movement process in a hysteresis curve (see FIG. 5) corresponding to each of FIGS.
  • FIG. 6A is a graph of the time change of the lens displacement in the small step drive.
  • a target position Pn is given when SMA3 is at the starting point position P0 at time t0, the lens starts moving toward the target position Pn, and reaches the target position Pn at time tn and settles.
  • this corresponds to a path moving from the state point S0 to the state point Sn along the path on the heating side of the hysteresis curve.
  • FIG. 7 is a graph when a large step drive is performed by a conventional control device.
  • the lens moves from the starting point position P0 toward the target position Pn, but passes through the target position Pn by one step drive, and a position corresponding to the state point Sn1 at time tn1. It reaches to Pn1. Since the servo control is performed after reaching the position Pn1, the position Pn2 (corresponding to the state point Sn2 (at the time tn2) remains with the displacement error ⁇ D from the target position Pn while returning to the target position Pn. > Pn).
  • the phenomenon in this large step is due to the fact that the acceleration by the servo control increases due to the large movement width and the movement speed becomes high because the movement width is large, as in the case of the small width step. In other words, overshoot is likely to occur.
  • the resistance value Rn1 of the state point Sn1 when passing through the target position Pn and reaching the position Pn1 due to the overshoot of the large step drive shows a resistance value lower than the target resistance value Rn. Therefore, it is driven in the reverse direction (heat dissipation process) by servo control, and is settled at the resistance value Rn2 of the state point Sn2 corresponding to the target resistance value Rn on the hysteresis curve or a resistance value approximate thereto, that is, the position Pn2.
  • the position Pn2 is the target position Pn as described above. Is displaced by a displacement error ⁇ D (see FIG. 7A).
  • the lens unit 1 is moved from the starting position P0 to the target position Pn.
  • the section D from the starting position P0 to the target position Pn is divided into a plurality of sections Da and Db, and a plurality of stages of moving processes are performed. .
  • Embodiment> ⁇ 2. Specific Configuration and Operation of Embodiment> ⁇ 2-1.
  • Outline of SMA actuator controller CT> The SMA actuator control device CT based on the technical idea of the present invention described above controls the actuator using the shape restoring force due to the temperature change of the wire-like SMA 3. Specifically, the control of the energization amount to the SMA 3 is variably set according to the movement step widths of the plurality of sections Da and Db divided up to the target position Pn (that is, the respective distances of the divided sections Da and Db). To do. Based on the set energization amount, the control signal is changed according to the operation command value to the actuator, and energization control to the SMA 3 is performed.
  • FIG. 8A is a block diagram illustrating a configuration of the SMA actuator control device CT according to the embodiment.
  • the SMA actuator control device CT includes the mechanical system illustrated in FIGS. 1 and 2 in the lens driving unit 100. It corresponds to a control system for controlling.
  • the SMA actuator 3 can be energized by the transistor 106 from the power supply line PL side between the power supply line PL for supplying the power supply voltage V and the ground line GL.
  • the SMA actuator 3 corresponds to the SMA actuator 3 of the lens driving unit 100 shown in FIGS.
  • Both ends of the SMA actuator 3 is connected to the resistance value detecting section 102, the resistance value detecting section 102, Ohm's law by, detecting the resistance value R SMA from the voltage V across the known current value I and the SMA actuator 3. Since the current value I becomes a substitute index in the one-to-one relationship with the voltage V across if known resistance value R SMA, to detect the voltage V across, it a physical detecting the resistance value R SMA Or mathematically equivalent. In FIG. 8, the constant current circuit and the detection timing circuit are omitted.
  • Resistance R SMA of the SMA actuator detected by the resistance value detecting section 102 is input to one input terminal of the comparator 103, the other input terminal of the comparator 103, the output from the command value division control section 104
  • a command position (specifically, a target resistance value Rn corresponding to the command position) is input.
  • the command value division control unit 104 is inputted with a target position Pn from a host control unit 101 constituted by a microcomputer or the like.
  • the resistance value R is detected instead of providing a displacement sensor by utilizing the above-described relationship between the SMA resistance value and the lens displacement (see FIG. 5).
  • the comparison between the actual resistance value obtained by this detection and the target resistance value indirectly compares the current lens displacement value with the target lens displacement value.
  • the comparison unit 103 outputs the result of comparing the input values of the actually measured resistance value RSMA and the target resistance value Rn to the energization control calculation unit 105.
  • the SMA actuator 3 is energized by determining the energization control value signal and inputting it to the transistor 106 according to the output result of the energization control calculation unit 105 (difference between the measured resistance value RSMA and the target resistance value Rn). It is heated by Joule heat.
  • the SMA actuator control device CT performs energization according to the command position of the lens unit 1 to the SMA actuator 3 and performs servo control using a detection value corresponding to the resistance value of the SMA actuator 3. .
  • the SMA actuator control device CT has the following functions in order to avoid the overshoot problem described above.
  • the command value division control unit 104 of the SMA actuator controller CT first adds the intermediate position P1 to the section D between the movement start point position P0 (FIG. 11A) of the lens unit 1 and the target position Pn.
  • a plurality of command positions P1, Pn including the target position Pn and the intermediate position P1 are set.
  • the plurality of command positions are sequentially given to the comparison unit 103 in order from the side closer to the start point position P0, and the lens unit 1 is moved in stages from the start point position P0 to the target position Pn.
  • the position P2 indicates a position where the SMA 3 has returned by a distance corresponding to a part of the overshoot during the static period provided between the completion of the first stage movement and the start of the second stage movement. This will be described later.
  • command value division control unit 104 of the SMA actuator control device CT has the following functions in addition to the stepwise movement unit 110.
  • the influence on the movement accuracy of the lens unit 1 to the target position Pn is mainly the influence of the hysteresis in the period immediately before reaching the target position Pn, that is, the final divided section Da, and the divided sections before that. This is a result of considering that the influence of the hysteresis of Da is relatively small. For this reason, by shortening the width (distance) of the final divided section and increasing the width of the other divided sections, the position accuracy at the target position Pn is improved and the total from the start position P0 to the target position Pn is increased. It is possible to achieve both the reduction of the displacement time.
  • the width of the final divided section Db is preferably set as a fixed value regardless of the distance difference (distance of the section D) between the starting point position P0 and the target position Pn. This is because the movement position accuracy to the target position Pn can be made uniform by setting the width of the final divided section to a fixed value regardless of the difference in distance between the start point position Pn and the target position Pn.
  • FIG. 11B shows a case where a plurality of intermediate positions P1, P3 are set in a section D between the starting point position P0 and the target position Pn and the section D is divided into a plurality of divided sections Da, Db, Dc.
  • the final divided section Dc is the shortest section among the divided sections Da, Db, and Dc, and the width of the final divided section Dc is fixed even if the distance of the section D is different. It is preferable to use a value.
  • the positions P2 and P4 of FIG. 11B indicate the positions returned by the same amount as the overshoot during the static period of the step movement boundary of each stage.
  • the command value division control unit 104 in FIG. 8B also includes a division interval width variable setting unit 120.
  • the width of at least one divided section Di other than the final divided section Dn is set to the difference between the start position P0 and the target position Pn ( It is variably set according to the distance of the section D).
  • the simplest example is the case of FIG. 11A in which the section D is divided into two divided sections ⁇ Da, Db ⁇ . Depending on the width of the section D, the divided sections Da other than the final divided section Db The width is variable.
  • the divided section width variable setting unit 120 does not overshoot the target position Pn due to overshoot. Pi and Pn are set. Further, when the number of divisions in the section D is variable, it is preferable that the number of divisions is increased as the width D is increased. However, if the number of divisions is excessive, an increase in the time until the target position Pn is reached cannot be ignored. Therefore, it is preferable to use several types of divisions depending on the section width D. For example, when the width of the section D is smaller than a predetermined threshold, it is divided into two, and when the width of the section D exceeds the threshold, the selection is divided into three. The specific division section width can be selected so that the total time for reaching the target position Pn and the positioning accuracy to the target position Pn are balanced.
  • the width of at least one divided section Di other than the final divided section Dn is variably set according to the difference (the width of the section D) between the starting point position P0 of the displacement of the lens unit 1 and the target position Pn.
  • the command value division control unit 104 in FIG. 8B also includes a single stage moving unit 140.
  • the target position Pn is set as the first command position of the movement destination from the start point position P0, thereby moving the lens unit 1 from the start point position P0 to the target position Pn in one step. Make it. Therefore, the single-stage moving unit 140 can realize movement control similar to the conventional one-stage movement.
  • the single stage moving unit 140 and the staged moving unit 110 can be selectively used according to the situation.
  • the command value division control unit 104 is selectively activated.
  • a conversion unit 130 is provided. Specifically, the selective activation unit 130 selectively activates the stepwise moving unit 110 when the difference (the width of the section D) between the start position P0 and the target position Pn exceeds a predetermined threshold, If the difference is less than or equal to the threshold, the single stage moving unit 140 is selectively activated. Further, the selective activation unit 130 stores the target value given from the upper control unit 101 when the lens unit 1 was moved last time, and uses this as the starting point position P0 that is the current position. The current position (starting point position P0) can also be determined based on the output value from the resistance value detecting unit 102.
  • the lens unit 1 when the difference between the starting point position P0 of the lens unit 1 and the target position Pn is equal to or smaller than a predetermined threshold value, one-step movement control is performed. Further, when the difference between the starting point position P0 and the target position Pn is small, the position error ⁇ D does not occur so much even if the stepwise movement process is not performed. Therefore, the lens unit 1 is moved directly to the target position Pn, and the control is performed. Time can be shortened.
  • the stepwise moving unit 110 moves the lens unit 1 to the next command position after a predetermined settling period (a non-zero finite period).
  • the settling period setting unit 111 is started.
  • the settling period may be a fixed value, or the settling period may be variably set.
  • the starting point position P0 of the displacement control is a position at the time when the displacement control to the previous target position is completed and the displacement control to the new target position Pn is started, and is an initialization position when the power is turned on. Is not limited. Therefore, the relationship between the starting point position P0 and the target position Pn is arbitrary.
  • FIG. 9 is a diagram for explaining the drive response of the SMA lens drive unit 100 according to the present embodiment.
  • the vertical axis, horizontal axis, and symbols used in the graph are the same as in FIGS.
  • FIG. 9 here is an example in which the lens is driven from the starting point position P0 to the target position Pn by two step drives.
  • position is used, such as “target position”, “current position”, and “command position”.
  • SMA 3 corresponding to these positions is used. (Or a voltage across the SMA 3 when a predetermined constant current is passed through the SMA 3).
  • Step ST1 First, in response to an initial operation in which the user turns on the power of the mobile phone or the camera mode, the power supply to the SMA actuator controller CT is turned on, and this operation flow is started.
  • a target position Pn corresponding to the displacement destination position of the imaging lens 10 is calculated by the upper control unit 101, and It is input to the command value division control unit 104 (see FIG. 8). Then, the command value division control unit 104 converts the target position Pn into the target resistance value Rn and holds it (see FIGS. 9A and 9B).
  • Step ST2 On the other hand, information regarding the current resistance value of the SMA 3 detected by the resistance value detection unit 102 is given to the command value division control unit 104, bypassing the comparison unit 103, and the current position Pi of the SMA 3 based on the current resistance value. Is calculated.
  • step ST2 is repeatedly executed by a repetition loop.
  • the current position P at time t0 corresponds to the starting point position P0, so this determination deviation
  • ⁇ P ⁇ corresponds to the distance in section D in FIG.
  • the selective active unit 130 selectively activates the stepped moving unit 110 and enters the divided movement mode.
  • step ST4 In step ST4 corresponding to the divided movement mode, it is determined which of the target position Pn and the current position P is larger. This is equivalent to determining the sign of the difference ⁇ P between the target position Pn and the current position P.
  • the current position P When the current position Pi is smaller than the target position Pn, the current position P is in front of the target position Pn. At that time, a position having a displacement smaller than the target position Pn by a predetermined distance C2, that is, A position Pf2 (FIG. 12) slightly before the target position Pn is set as the movement command value.
  • the current position P When the current position P is larger than the target position Pn, the current position P exists on the side farther than the target position Pn. At that time, the displacement variable is larger by a predetermined distance C2 from the target position Pn.
  • the position, that is, the position Pr2 slightly ahead of the target position Pn is set as the movement command value.
  • the target position Pn is used as the movement command value.
  • the positions Pf2 and Pr2 separated from the target position Pn by the distance C2 are set as intermediate positions, and the intermediate positions are set as the current command positions.
  • the two threshold values C1 and C2 may be the same value or different values. However, in the latter case, C1> C2. This prevents the situation where the intermediate positions Pf2 and Pr2 are set farther than the current position P when viewed from the target position Pn.
  • the ratio of C1: C2 is selected from the range of 1-3: 1.
  • the command position determined in this way is expressed by a resistance value corresponding to the command position, and is output to the comparison unit 103 (FIG. 8A) to perform servo control to move to the command position.
  • the command position and current position in the servo control are expressed by the resistance value of SMA3 (more precisely, the voltage value at both ends of SMA3), but in the following, it will be described as "position” like "command position” and "current position". To do.
  • Step ST5 When the movement control to the command position is completed, the driving is stopped only for the period set in advance in the settling period setting unit 111 included in the stepwise moving unit 110, and the SMA 3 is settled.
  • the settling period set in the settling period setting unit 111 is variable.
  • a resistance value R1 corresponding to the front position P1 (P0 ⁇ P1 ⁇ Pn: FIG. 11A) is given as a proxy index for the command position P1.
  • the movement control toward the first command position P1 is performed by the first step driving, but since the first step driving has a relatively large movement width Da, an overshoot occurs.
  • the position P2 at time t2 when it has returned to incomplete and settled is closer to the starting position P0 than the original command position P1 (P2 ⁇ P1).
  • the resistance value has a relationship of R1 ⁇ R2.
  • Steps ST6 to ST8 When the static period elapses, the target position Pn is set as the next designated position, and the movement of the lens unit 1 is resumed. Also, the settling time is allowed to elapse at the end of the movement.
  • the SMA 3 reaches the target position Pn or its vicinity with high accuracy and stops.
  • the state point on the heat dissipation side path of the hysteresis curve returns to the heating side path again in this process, and at time tn, the state point Sn corresponding to the target position Pn is reached.
  • Servo control is performed to maintain the temperature of the SMA 3 so as to stay at this state point Sn until the next target position is given.
  • step ST6 ⁇ Detour from step ST3 to step ST6:
  • ⁇ P the determination deviation
  • ⁇ P which is the absolute value of the difference between the current position P and the target position Pn does not exceed the threshold value C1
  • steps ST4 to ST5 are bypassed, The process directly enters step ST6. Therefore, at this time, the target position Pn is set as the command position and the movement control is executed immediately without going through the intermediate movement stage where the intermediate position P1 is once set as the command position.
  • step ST6 is performed by the selective enemy activation unit 130 in FIG. 8B selectively activating the single-stage movement command unit 140 so that the target position can be obtained only in a single stage. This corresponds to the control of moving to Pn.
  • the above control sequence is a simple calculation using set values such as threshold values C1 and C2 as constants (fixed or variable constants), so that the control is not complicated and a correction table is provided for each product. There is no need. Therefore, it can be realized even with a relatively small-scale digital logic circuit. In addition, since no special element is required mechanically, accurate position control can be realized while suppressing the complexity and cost increase of the system.
  • the positions P1 to P4 are positions separated from the target position Pn by a distance corresponding to constants C1 to C4, and correspond to the divided widths Da to Dc for each of the three divided sections.
  • the command position is set in order from the side closer to the start point position P0. The same applies when the number of divided sections is 4 or more.
  • the SMA actuator control device of the present invention can be used for various drive units, but is particularly suitable when SMA is used in a drive unit for optical components such as lenses and mirrors.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Lens Barrels (AREA)

Abstract

L'invention concerne un dispositif de commande (CT) d'actionneur en alliage à mémoire de forme (SMA), comportant un alliage à mémoire de forme et fonctionnant de sorte que de l'électricité est fournie à l'alliage à mémoire de forme en fonction de la position de commande d'un mécanisme mobile, et comportant une servocommande exécutée en utilisant une valeur de détection qui correspond à la valeur de résistance de l'alliage à mémoire de forme. Quand le mécanisme mobile est déplacé d'une position de départ (P0) à une position cible (Pn), l'effet d'hystérésis qui est fonction de l'historique de mouvement depuis le début du mouvement peut être réduit et une commande de position précise peut être réalisée par l'ajout d'au moins une position intermédiaire (P1, P3) et par l'utilisation de cette position en tant que position de commande lors d'une étape intermédiaire.
PCT/JP2011/079000 2011-01-05 2011-12-15 Dispositif de commande d'actionneur en alliage à mémoire de forme et unité d'entraînement à composant optique Ceased WO2012093567A1 (fr)

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JP2011000635A JP2014055519A (ja) 2011-01-05 2011-01-05 形状記憶合金アクチュエータ制御装置および光学部品駆動ユニット
JP2011-000635 2011-01-05

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH707658A1 (de) * 2013-02-27 2014-08-29 Unovatis Gmbh Drehstellantrieb.
CN104678529A (zh) * 2013-11-30 2015-06-03 鸿富锦精密工业（深圳）有限公司 形状记忆合金致动器的驱动系统和驱动方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102020119218B3 (de) 2020-07-21 2021-11-11 Carl Zeiss Meditec Ag Injektoranordnung und Injektor mit der Injektoranordnung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009063845A1 (fr) * 2007-11-12 2009-05-22 Konica Minolta Opto, Inc. Dispositif de commande d'alliage à mémoire de forme
JP2009229781A (ja) * 2008-03-24 2009-10-08 Konica Minolta Opto Inc 駆動機構および駆動装置
JP2010051059A (ja) * 2008-08-19 2010-03-04 Fujinon Corp 駆動装置及び光学装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009063845A1 (fr) * 2007-11-12 2009-05-22 Konica Minolta Opto, Inc. Dispositif de commande d'alliage à mémoire de forme
JP2009229781A (ja) * 2008-03-24 2009-10-08 Konica Minolta Opto Inc 駆動機構および駆動装置
JP2010051059A (ja) * 2008-08-19 2010-03-04 Fujinon Corp 駆動装置及び光学装置

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH707658A1 (de) * 2013-02-27 2014-08-29 Unovatis Gmbh Drehstellantrieb.
EP2772647A1 (fr) * 2013-02-27 2014-09-03 Unovatis GmbH Actuateur rotatif
CN104678529A (zh) * 2013-11-30 2015-06-03 鸿富锦精密工业（深圳）有限公司 形状记忆合金致动器的驱动系统和驱动方法

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