JP2020133413A - Controller and tactile sensation imparting device - Google Patents

Abstract

To provide a technique capable of suppressing fluctuation in an actual acceleration of a drive target driven by an actuator.SOLUTION: A controller is used to control an actuator 10. The actuator 10 comprises a stretchable member made of a shape memory alloy that is stretchable due to a temperature change, and can drive a drive target 16 due to contraction of the stretchable member. The controller comprises a command value setting unit 36 that sets a command value Vc, and a control unit 38 that controls the actuator 10 using the command value Vc. The command value setting unit 36 feeds back an actual acceleration Aact of the drive target 16 driven by the actuator 10, and corrects the command value Vc so that the actual acceleration Aact approaches a target acceleration Aref.SELECTED DRAWING: Figure 4

Description

The present invention relates to an actuator control device using a shape memory alloy.

Conventionally, an actuator using a shape memory alloy (SMA) (hereinafter, also referred to as an SMA actuator) is known. It is provided with a stretchable member made of a shape memory alloy, and can drive a drive target by utilizing expansion and contraction due to a temperature change of the stretchable member. Patent Document 1 describes an energization control device that drives an elastic member by controlling energization of the elastic member.

Japanese Unexamined Patent Publication No. 2006-183564

The present inventor examined the SMA actuator and obtained the following findings. In the SMA actuator, the actual acceleration of the drive target driven by the SMA actuator fluctuates due to various factors. A technology that takes this measure has not yet been proposed, and improvement is desired.

A certain aspect of the present invention is made in view of such a problem, and one of the objects thereof is to provide a technique capable of suppressing fluctuations in the actual acceleration of a driven object driven by an actuator.

The first aspect of the present invention is a control device. The control device of the first aspect is a control device used for controlling an actuator, and the actuator includes a stretchable member made of a shape memory alloy that can expand and contract with a temperature change, and a drive target is driven by shrinkage deformation of the stretchable member. The control device is driveable and includes a command value setting unit that sets a command value and a control unit that controls the actuator using the command value, and the command value setting unit is driven by the actuator. The actual acceleration of the driven object is fed back, and the command value is corrected so that the actual acceleration approaches the target acceleration.

According to this aspect, fluctuations in the actual acceleration of the driven object driven by the actuator can be suppressed.

It is a schematic diagram of the electric device of 1st Embodiment. It is a block diagram which shows the main part of the electric device of 1st Embodiment. It is a side sectional view which shows an example of the actuator of 1st Embodiment. It is a block diagram which shows the main part of the control device of 1st Embodiment. It is a flowchart which shows the operation of the control device in the test mode of 1st Embodiment.

The background that led to the idea of the technique of the embodiment will be described. The actual acceleration of the driven object driven by the actuator tends to decrease as the ambient temperature around the telescopic member decreases, and increases as the ambient temperature increases.

Further, the actual acceleration of the driving target may fluctuate greatly due to the influence of errors such as assembly error and dimensional error of each component of the actuator, and the influence of aging deterioration. For example, the contact area of the telescopic member with respect to the stator and the mover fluctuates due to the variation in the arrangement position of the telescopic member, and the frictional resistance with respect to the telescopic member fluctuates. When such a fluctuation occurs, the movement of the mover driven by the contraction deformation of the telescopic member is affected, and the actual acceleration of the driving target fluctuates. In addition to this, for example, if the natural length of the telescopic member fluctuates due to aged deterioration of the telescopic member, the movement of the mover driven by the contraction deformation of the telescopic member is affected, and the actual acceleration of the driven object fluctuates.

As a countermeasure, in the control device of the present embodiment, the actual acceleration of the driving target is fed back, and the command value used for controlling the actuator is corrected so that the actual acceleration approaches the target acceleration. As a result, even if the actual acceleration of the driven object driven by the actuator may fluctuate, the actual acceleration can be made to follow the target acceleration, and the fluctuation of the actual acceleration can be suppressed.

Hereinafter, an example of the embodiment of the present invention will be described. The same components are designated by the same reference numerals, and duplicate description will be omitted. In each drawing, for convenience of explanation, some of the components are appropriately omitted, and the dimensions thereof are appropriately enlarged or reduced. The drawings shall be viewed according to the orientation of the symbols.

(First Embodiment)
See FIGS. 1 to 3. The actuator 10 is mounted on the device main body 14 of the electrical device 12. The actuator 10 can drive the drive target 16 movably supported by the device main body 14. The electric device 12 of the present embodiment is a touch panel device, and the drive target 16 is a touch panel. The electric device 12 includes an acceleration sensor 18 for detecting the acceleration of a component of the electric device 12 different from the actuator 10 in addition to the device main body 14 that supports other components of the electric device 12 such as the actuator 10. .. The "component of the electric device 12" here means the device main body 14 of the electric device 12 in the present embodiment, but may be a drive target 16 of the actuator 10.

The acceleration sensor 18 will be described by taking a 3-axis acceleration sensor as an example, but may be a 1-axis acceleration sensor or a 2-axis acceleration sensor. As the acceleration sensor 18, for example, various sensors of piezoresistive type, capacitance type, and heat detection type may be used. The output value of the acceleration sensor 18 is used for a purpose other than the control of the actuator 10. The output value of the acceleration sensor 18 of the present embodiment indicates the acceleration of the device main body 14, and is used for detecting the posture thereof. The posture of the device main body 14 is detected by processing the output value of the acceleration sensor 18 by a higher-level control device (not shown) of the electric device 12.

The tactile sensation imparting device 20 in which the actuator 10 is used will be described. The tactile sensation device 20 can give a tactile sensation to the user U touching the drive target 16 by vibrating the drive target 16 by the actuator 10 in conjunction with the touch operation of the user U. In addition to the actuator 10, the tactile sensation giving device 20 mainly includes a touch detecting unit 22, an urging unit 24, and a control device 26. The control device 26 will be described later.

The actuator 10 can drive the drive target 16 in a specific drive direction Pa. The drive direction Pa is, for example, the in-plane direction or the out-of-plane direction of the touch panel.

The touch detection unit 22 can detect a touch operation on the drive target 16. The touch detection unit 22 is, for example, a capacitive touch sensor incorporated in a touch panel or the like.

The urging unit 24 urges the drive target 16 in the opposite drive direction Pb opposite to the drive direction Pa. The urging portion 24 is an elastic body such as a coil spring.

The actuator 10 of the present embodiment includes a stator 28, a mover 30, and an expansion / contraction member 32.

The stator 28 is attached to the device body 14 of the electrical device 12, and its position with respect to the device body 14 is fixed. The mover 30 faces the stator 28 and can move in the direction facing the stator 28 as the movable direction. The mover 30 can transmit the movement of the drive direction Pa to the drive target 16 with one side in the movable direction as the drive direction Pa.

The telescopic member 32 exemplifies a linear wire, but may be a band-shaped belt or the like. The telescopic member 32 is made of a shape memory alloy that can be stretchable by changing the temperature. The shape memory alloy of this embodiment is a Ni—Ti alloy. The stretchable member 32 made of a shape memory alloy can be contracted and deformed by reverse transformation (austenite transformation) due to heating, and can be stretched and deformed by martensitic transformation due to cooling. The telescopic member 32 is stretched so that the mover 30 can be driven in the drive direction Pa by contraction deformation, and both ends thereof are fixed to the stator 28. Both ends of the telescopic member 32 are electrically connected to the control unit 38 (described later) of the control device 26.

An example of the operation of the tactile sensation imparting device 20 will be described. When the telescopic member 32 is energized under the control of the control unit 38 (described later) of the control device 26, the telescopic member 32 contracts and deforms. When the telescopic member 32 contracts and deforms, the mover 30 is driven in the drive direction Pa, and the movement of the mover 30 is transmitted to the drive target 16, so that the drive target 16 is also driven in the drive direction Pa. At this time, the drive target 16 is driven in the drive direction Pa against the urging force of the urging unit 24.

When the power supply to the telescopic member 32 by the control unit 38 is stopped, the telescopic member 32 is stretched and deformed so as to be restored to its original shape by heat dissipation cooling. Along with this, the transmission of the force from the telescopic member 32 to the driving target 16 is released, and the driving target 16 is pushed back in the counter-driving direction Pb by the urging force of the urging portion 24. The tactile sensation imparting device 20 vibrates the drive target 16 by momentarily performing the movements of the drive direction Pa and the counter drive direction Pb. As a result, the vibration of the drive target 16 is transmitted to the user who is touching the drive target 16, and the user is given a tactile sensation.

Refer to FIGS. 2 and 4. The control device 26 is used to control the actuator 10. The control device 26 includes an acceleration acquisition unit 34, a command value setting unit 36, a control unit 38, and a storage unit 40. Each block of the control device 26 is realized by various electronic parts such as a computer CPU and mechanical parts in terms of hardware, and is realized by a computer program or the like in terms of software. Here, the functional blocks realized by their cooperation are drawn. These functional blocks are realized by a combination of hardware elements and software elements, or only by hardware elements.

The acceleration acquisition unit 34 acquires the actual acceleration Aact of the drive target 16 based on the output value Vout of the acceleration sensor 18. The acceleration sensor 18 of the present embodiment detects the acceleration of a component (equipment main body 14) of the electric device 12 different from the drive target 16. In this case, the acceleration acquisition unit 34 acquires the actual acceleration Aact of the drive target 16 based on the following idea.

There is a certain correlation α between the actual acceleration Aact of the drive target 16 and the output value Vout of the acceleration sensor 18. This correlation α is, for example, a positive correlation such that the output value Vout of the acceleration sensor 18 increases as the actual acceleration Aact of the drive target 16 increases. The storage unit 40 stores such a predetermined correlation α. This correlation α is stored in the form of an expression, table, map, or the like. In this correlation α, for example, the actual acceleration Aact is uniquely determined with respect to the output value Vout. This correlation α can be obtained by experiments, analyzes, and the like. The acceleration acquisition unit 34 acquires the actual acceleration Aact of the drive target 16 based on the output value Vout of the acceleration sensor 18 and the correlation α stored in the storage unit 40. Specifically, the acceleration acquisition unit 34 acquires the actual acceleration Aact of the drive target 16 corresponding to the output value Vout of the acceleration sensor 18 by referring to the correlation α read from the storage unit 40.

In the present embodiment, as the actual acceleration Aact of the drive target 16, the difference between the maximum value and the minimum value of the acceleration of the drive target 16 when the drive target 16 is vibrated a predetermined number of times (once in this example) by the actuator 10. Use the value (peak peak value). As this actual acceleration Aact, the peak peak value of the acceleration of the driving target 16 when the driving target 16 is simply vibrated is used.

The command value setting unit 36 sets the command value Vc used for controlling the actuator 10. This command value Vc defines the operating conditions of the actuator 10. In the present embodiment, the voltage value of the applied voltage applied to the telescopic member 32 is used as such a command value Vc. This applied voltage has a role as an operation amount that affects the control amount when the actual acceleration Aact of the drive target 16 driven by the actuator 10 is regarded as a control amount. The command value setting unit 36 sets the command value Vc so that the telescopic member 32 can be contracted and deformed by reverse transformation.

The control unit 38 controls the operation of the actuator 10 by using the command value Vc set by the command value setting unit 36. In controlling the actuator 10 in this way, the control unit 38 of the present embodiment energizes the telescopic member 32 for a predetermined energization time by the command value Vc (voltage value) set by the command value setting unit 36. Stop energizing.

Here, the command value setting unit 36 of the present embodiment feeds back the actual acceleration Aact of the drive target 16 driven by the actuator 10 and corrects the command value Vc so that the actual acceleration Aact approaches the target acceleration Aref. .. Specifically, the command value setting unit 36 calculates a deviation based on the actual acceleration Aact and the target acceleration Aref of the drive target 16, and based on the deviation, sets the command value Vc so that the actual acceleration Aact approaches the target acceleration Aref. to correct. At this time, the command value setting unit 36 corrects the command value Vc based on the deviation according to control algorithms such as P control, PI control, and PID control. The target acceleration Aref may be a predetermined fixed value or a variable value input by an operation on a user's input operation unit (not shown).

The control device 26 of the present embodiment can perform a test mode and a normal operation mode. The test mode is a mode for adjusting the command value Vc of the actuator 10 prior to the operation of the actuator 10 in the normal operation mode. The normal operation mode is a mode for operating the actuator 10 using the command value Vc adjusted in the test mode.

The test mode is performed when a predetermined test start condition is satisfied. The test start condition is, for example, when the power of the electric device 12 is turned on or when there is an operation on the user's input operation unit (not shown) for starting the test mode. The normal operation mode is performed when a predetermined normal operation start condition is satisfied. In the present embodiment, the normal operation start condition is a case where the touch operation by the drive target 16 is detected by the touch detection unit 22.

In the test mode, first, the drive target 16 is sporadically driven by the actuator 10 under the control of the control unit 38 using the initial command value set by the command value setting unit 36, and the drive target 16 at that time is driven. The actual acceleration Aact is acquired by the acceleration acquisition unit 34. After that, the actual acceleration Aact acquired by the acceleration acquisition unit 34 is fed back, and the command value Vc of the actuator 10 is corrected by the command value setting unit 36 so that the actual acceleration Aact approaches the target acceleration Aref. In this way, the actual acceleration Aact of the driving target 16 when the driving target 16 is driven in a single-shot manner is acquired, and the series of steps of feeding back the actual acceleration to correct the command value Vc is repeated. This series of flow is repeated until the actual acceleration Aact of the drive target 16 falls within the predetermined target range. Thereby, the command value Vc of the actuator 10 when the actual acceleration Aact of the drive target 16 falls within the target range can be specified.

In the normal operation mode, the operation of the actuator 10 is controlled by the control unit 38 using the command value Vc specified by the test mode. In the normal operation mode, the actuator 10 is controlled by using the command value Vc when the actual acceleration Aact falls within the target range.

An example of the operation of the tactile sensation giving device 20 using the above control device 26 will be described.

First, an example of the operation when the test mode is performed will be described. See FIG. In the test mode, first, the actuator 10 is controlled by the control unit 38, so that the actuator 10 drives the drive target 16 (S10). When the drive target 16 is driven for the first time, the actuator 10 is controlled using a predetermined initial command value. The acceleration acquisition unit 34 acquires the actual acceleration Aact of the drive target 16 at this time based on the output value Vout of the acceleration sensor 18 (S12).

Consider the case where the actual acceleration Aact of the drive target 16 does not fall within the predetermined target range (N in S14). In this case, the command value setting unit 36 feeds back the actual acceleration Aact of the drive target 16 and corrects the command value Vc (voltage value of the applied voltage) of the actuator 10 so that the actual acceleration Aact approaches the target acceleration Aref. (S16). After that, the actuator 10 is again controlled by the control unit 38, so that the actuator 10 drives the drive target 16 (S10). At the time of driving the drive target 16 from the second time onward, the actuator 10 is controlled by using the corrected command value Vc.

When the actual acceleration Aact of the drive target 16 falls within the predetermined target range (Y in S14), the command value setting unit 36 stores the command value Vc when the actual acceleration Aact is obtained in the storage unit 40. (S18). After this, the test mode is terminated.

Next, an example of the operation when the normal operation mode is performed will be described. In the normal operation mode, the command value Vc stored in S18 is read from the storage unit 40, and the actuator 10 is controlled by the read command value Vc to drive the drive target 16 by the actuator 10. The actuator 10 is controlled by the command value Vc obtained when the actual acceleration Aact of the drive target 16 falls within the target range.

The effects of the above techniques will be described. The control device 26 of the present embodiment acquires the actual acceleration Aact of the drive target 16 based on the output value Vout of the acceleration sensor 18 for detecting the acceleration of the component of the electric device 12 different from the actuator 10. A unit 34 is provided. Therefore, the acceleration sensor 18 originally used in the electric device 12 to be incorporated in the actuator 10 can be shared to correct the command value Vc of the actuator 10. Therefore, it is not necessary to use the dedicated acceleration sensor 18 for the actuator 10, and the product cost of the actuator 10 can be reduced accordingly.

The command value setting unit 36 of the control device 26 acquires the actual acceleration Aact of the drive target 16 based on the output value Vout of the acceleration sensor 18 and the correlation α. Therefore, even if the acceleration sensor 18 does not detect the actual acceleration Aact of the drive target 16, the actual acceleration Aact of the drive target 16 can be obtained by using the output value Vout of the acceleration sensor 18. Therefore, the acceleration sensor 18 originally used in the electric device 12 is shared, and the correction of the command value Vc of the actuator 10 becomes easier.

When the actuator 10 is incorporated into the tactile sensation apparatus 20, the tactile sensation given to the user is greatly changed by the fluctuation of the actual acceleration Aact of the drive target 16 driven by the actuator 10. In this respect, according to the present embodiment, since the fluctuation of the actual acceleration Aact of the drive target 16 can be suppressed, the change in the tactile sensation given to the user can be suppressed.

In order to deal with the fluctuation of the actual acceleration Aact of the drive target 16, for example, a method of correcting the command value Vc of the actuator 10 by using the ambient temperature of the actuator 10 can be considered. However, when this method is used, the influence of the error of each component of the actuator 10 is not taken into consideration. Therefore, even if the command value Vc is corrected to the optimum value in relation to the ambient temperature, the actual acceleration Aact of the drive target 16 may be significantly increased from the target acceleration Aref. When the actual acceleration Aact of the drive target 16 becomes significantly large in this way, there is a concern that the load on the telescopic member 32 will increase. In this regard, according to the present embodiment, the actual acceleration Aact of the drive target 16 is fed back to correct the command value Vc of the actuator 10. Therefore, it is possible to avoid a situation in which the actual acceleration Aact of the drive target 16 is significantly increased from the target acceleration Aref, and it is possible to avoid a situation in which an excessive load is applied to the telescopic member 32.

Other modifications of each component will be described.

The specific structure of the actuator 10 is not particularly limited as long as the mover 30 can be driven in the drive direction Pa by the contraction deformation of the telescopic member 32. The composition of the shape memory alloy constituting the telescopic member 32 is not particularly limited, and a Ni—Ti—Cu based alloy may be used.

Although the example in which the drive target 16 is a touch panel has been described, the driving target 16 is not limited to this. For example, a switch such as an on / off switch may be used.

The actual acceleration Aact of the drive target 16 may be any one indicating the acceleration of the drive target 16, and is not limited to the peak peak value. For example, as the actual acceleration Aact, either the maximum value or the minimum value of the acceleration of the drive target 16 when the drive target 16 is vibrated a predetermined number of times may be used.

The acceleration sensor 18 detects the acceleration of a component of the electric device 12 different from the drive target 16, and the acceleration acquisition unit 34 uses the output value Vout of the acceleration sensor 18 and the correlation α to use the actual acceleration Aact of the drive target 16. An example of acquiring is explained. When the acceleration sensor 18 detects the acceleration of the drive target 16, the acceleration acquisition unit 34 acquires the actual acceleration Aact of the drive target 16 based on the output value Vout of the acceleration sensor 18 without using the above-mentioned correlation α. May be good. In any case, the acceleration acquisition unit 34 may acquire the actual acceleration Aact of the drive target 16 based on the output value Vout of the acceleration sensor 18. In addition to this, the acceleration of the mover 30 of the actuator 10 may be detected by the acceleration sensor 18, and the actual acceleration Aact of the drive target 16 may be acquired based on the output value Vout of the acceleration sensor 18.

The command value Vc corrected by the command value setting unit 36 has been described with reference to the applied voltage applied to the telescopic member 32 as an example, but is not limited to this. For example, it may be the current value of the current energized in the telescopic member 32, the energization time, or the like, or any combination thereof.

The method of controlling the applied voltage by the control unit 38 is not particularly limited. The control unit 38 may control the applied voltage applied to the telescopic member 32 by generating a desired applied voltage based on the power supply voltage by using, for example, a pulse width modulation circuit. In addition to this, for example, it may be realized by stepping down the power supply voltage to a desired applied voltage by a dropper circuit. In addition to this, the applied voltage may be controlled by using a plurality of capacitors having different capacitances. More specifically, the capacitor has a characteristic that the larger the capacitance, the slower the voltage drop rate due to the discharge, and the higher the discharge current voltage. Utilizing this, the discharge current of any of a plurality of capacitors having different capacitances can be supplied to the expansion / contraction member 32, and the applied voltage may be controlled by switching the supply source capacitor. This capacitor is, for example, an electrolytic capacitor or the like.

In the normal operation mode, an example of controlling the actuator 10 using the command value Vc specified by the test mode has been described. Even in this normal operation mode, feedback control may be performed in which the actual acceleration Aact of the drive target 16 is fed back to correct the command value Vc of the actuator 10. Further, when such feedback control is performed in the normal operation mode, the test mode may not be provided.

The embodiments and modifications of the present invention have been described in detail above. The above-described embodiments and modifications are merely specific examples for carrying out the present invention. The contents of the embodiments and modifications do not limit the technical scope of the present invention, and many design changes such as modification, addition, and deletion of components can be made without departing from the idea of the invention. In the above-described embodiment, the content that can be changed in design is emphasized by adding the notation "embodiment", but the design change is permitted even if the content does not have such a notation. Any combination of the above components is also valid as an aspect of the present invention. The hatching attached to the cross section of the drawing does not limit the material of the object to which the hatching is attached.

10 ... Actuator, 12 ... Electrical equipment, 14 ... Equipment body, 16 ... Drive target, 18 ... Acceleration sensor, 20 ... Tactile sensation device, 22 ... Touch detector, 26 ... Control device, 32 ... Telescopic member, 34 ... Acceleration acquisition Unit, 36 ... Command value setting unit, 38 ... Control unit, 40 ... Storage unit.

Claims (4)

A control device used to control actuators
The actuator has a stretchable member made of a shape memory alloy that can expand and contract with a temperature change, and can drive a drive target by shrinking and deforming the stretchable member.
This control device
The command value setting unit that sets the command value and
A control unit that controls the actuator using the command value is provided.
The command value setting unit is a control device that feeds back the actual acceleration of the drive target driven by the actuator and corrects the command value so that the actual acceleration approaches the target acceleration. The drive target is movably supported by the main body of the electric device.
The electrical device comprises an acceleration sensor for detecting the acceleration of a component of the electrical device that is different from the actuator.
This control device includes an acceleration acquisition unit that acquires the actual acceleration of the driving target based on the output value of the acceleration sensor.
The control device according to claim 1, wherein the command value setting unit feeds back the actual acceleration acquired by the acceleration acquisition unit to correct the command value. A storage unit for storing the correlation between the output value of the acceleration sensor and the actual acceleration of the driving target is provided.
The control device according to claim 2, wherein the acceleration acquisition unit acquires the actual acceleration based on the output value of the acceleration sensor and the correlation. The control device according to any one of claims 1 to 3 and
A touch detection unit that can detect a touch operation on the drive target by the user,
A tactile sensation device comprising an actuator made of a shape memory alloy that can be expanded and contracted by a temperature change, and an actuator that can drive a drive target by contraction deformation of the expansion and contraction member.

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