Driving apparatus and distortion control method

The present invention relates to a drive device and a strain control method.

In recent years, there has been an increasing need for technology for detecting distortion generated in a drive unit such as an actuator. For example, in a robot hand, it is necessary to strictly control the amount of distortion of the drive unit in order to grip the object more appropriately and accurately. Therefore, a means for detecting the distortion of the drive unit is required. Currently, an electric strain gauge is the mainstream as a strain detecting means. The electric strain gauge is a mechanical sensor capable of calculating the amount of strain by measuring the change in electrical resistance due to deformation.

As an example of the above-mentioned electric strain gauge, a technique that reduces measurement error and enables highly accurate uniaxial displacement measurement is disclosed (see, for example, Patent Document 1). Further, a technique capable of reducing the influence of distortion due to the operation of the actuator and improving the detection accuracy of the sensor is disclosed (see, for example, Patent Document 2). Both of the techniques described in Patent Document 1 and Patent Document 2 detect distortion of the driving unit by attaching a sensor to the driving unit, and control the distortion of the driving unit based on the detected value.

In addition, as a distortion detecting means, there is another method called the moire method. The moire method is a method of detecting distortion by drawing a grid pattern on the surface of a driving unit and performing image analysis of changes in the grid pattern.

<p><patcit num="1"><text>Japanese Unexamined Patent Publication No. 7-321385</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2011-72180</text></patcit></p>

<p> Generally, when detecting the distortion of the drive unit, it is important to transmit the detected distortion information to the signal processing unit without causing a time lag as much as possible. Further, since an impact is often applied to the drive unit due to an external force or the like, it is necessary to take measures against the impact. From the above, the means for detecting the distortion of the drive unit is required to have two performances, high-speed detection and high impact resistance. However, in the prior art, there is no strain detecting means that simultaneously satisfies the above two performances (high-speed detectability and high impact resistance). For example, the electric strain gauges of the techniques described in Patent Document 1 and Patent Document 2 can detect strain at high speed, but they are made very brittle so as not to interfere with driving, so that an impact is impacted. There is a problem that it is weak and fragile. Further, when the moire method is used, it has high impact resistance because it is possible to engrave a grid pattern directly on the driving body, but it takes a long time for image analysis, so that the distortion detection speed is slow. There is.</p><p> An object of the present invention is to provide a drive device and a strain control method capable of detecting strain while simultaneously satisfying high-speed detectability and high impact resistance.</p>

<p> The invention according to claim 1 has been made in order to achieve the above object, and is used in a driving device.<u style="single">、</u><u style="single"> Enter</u>A drive unit that causes distortion based on the applied energy, a light source that emits light, and light that is formed on the surface of the drive unit and causes distortion due to deformation of the drive unit and is emitted from the light source. A marker that reflects or transmits light, a detection unit that detects the light intensity of light reflected or transmitted by the marker, and a signal process that calculates the amount of distortion generated in the marker based on the light intensity detected by the detection unit. A unit and a strain control unit that controls the strain amount of the drive unit based on the strain amount calculated by the signal processing unit are provided, and the marker is emitted from the light source onto the surface of the drive unit. Has a periodic microstructure below the wavelength of light<u style="single">At the same time, it is integrated with the drive unit.</u><u style="single"> The drive unit and the marker are made of a material that generates plasmons.</u>It is characterized by that.</p><p> The invention according to claim 2 is characterized in that, in the driving device according to claim 1, the driving unit and the marker are made of a material containing at least a hydrogen storage alloy.</p><p> The invention according to claim 3 is characterized in that, in the driving device according to claim 2, the hydrogen storage alloy is an alloy containing palladium.</p><p> Claim<u style="single">4</u>The invention according to claim 1 to claim 1.<u style="single">3</u>In the driving device according to any one of the above items, the marker is formed in a flat plate shape having a first medium and a second medium having different refractive indexes, and the second medium is contained in the first medium. The second medium is formed so that the maximum length in the direction parallel to the light receiving surface of the marker is shorter than the wavelength of the light emitted from the light source. To do.</p><p> Claim<u style="single">5</u>The invention described in is claimed.<u style="single">4</u>In the drive device according to the above, the second medium is arranged so that at least one is present in a direction parallel to the deformation direction of the marker.</p><p> Claim<u style="single">6</u>The invention described in is claimed.<u style="single">4 or 5</u>The driving device according to the above is characterized in that a gas is housed in a region where the second medium is housed.<u style="single">The invention according to claim 7 is the drive device according to any one of claims 1 to 6.</u><u style="single"> The light source emits a plurality of lights polarized in a direction parallel to the light receiving surface of the marker and having different polarization directions.</u><u style="single"> The detection unit further detects the polarization direction of the light reflected or transmitted by the marker.</u><u style="single"> The signal processing unit is characterized in that the direction of distortion generated in the marker is calculated based on the light intensity and the polarization direction detected by the detection unit.</u></p><p> Claim<u style="single">8</u>The invention described in<u style="single">、</u><u style="single"> Enter</u>A drive unit that causes distortion based on the applied energy, a light source that emits light, and a surface of the drive unit are formed so as to have a periodic fine structure equal to or less than the wavelength of the light emitted from the light source. This is a distortion control method for a drive device including a marker that reflects or transmits light emitted from the light source while causing distortion due to deformation of the drive unit, and is a method of controlling distortion of the light that is reflected or transmitted by the marker. A step of detecting the light intensity of the above, a step of calculating the amount of strain generated in the marker based on the detected light intensity, and a step of controlling the amount of strain of the driving unit based on the calculated amount of strain. And have<u style="single">And</u><u style="single"> The marker has a periodic fine structure equal to or less than the wavelength of the light emitted from the light source on the surface of the drive unit, and is integrated with the drive unit.</u><u style="single"> The drive unit and the marker are made of a material that generates plasmons.</u>It is characterized by that.</p>

<p> According to the present invention, strain can be detected while simultaneously satisfying high-speed detectability and high impact resistance.</p>

<figref num="1">It is a figure which shows the schematic structure of the drive device which concerns on this embodiment.</figref><figref num="2">It is a functional block diagram which shows the control structure of the drive device which concerns on this embodiment.</figref><figref num="3">It is a perspective view which shows the structure of the drive part.</figref><figref num="4">It is a figure which shows an example of the behavior when power is input to the drive part of FIG.</figref><figref num="5">It is a figure which shows an example of the behavior when an external force other than power is generated in the drive part of FIG.</figref><figref num="6">It is a side view of the drive part of FIGS. 3 to 5.</figref><figref num="7">It is a top view which shows the structure of a marker.</figref><figref num="8">It is sectional drawing which shows an example of the part VIII-VIII of FIG.</figref><figref num="9">It is a top view which shows the state when the marker is deformed in the X direction.</figref><figref num="10">It is a top view which shows the state when the marker is deformed in the Y direction.</figref><figref num="11">It is a figure which shows the change of the reflected light spectrum by the distortion of a marker.</figref><figref num="12">It is a figure which shows the correspondence relationship between the distortion amount in the X direction of a marker, and the reflected light intensity.</figref><figref num="13">It is a flowchart which shows the operation of the drive device which concerns on this embodiment.</figref><figref num="14">It is a figure which shows the schematic structure of the drive device which concerns on a modification.</figref><figref num="15">It is a top view which shows the modification of the structure of a marker.</figref><figref num="16">It is sectional drawing of the AA line in FIG.</figref><figref num="17">It is sectional drawing of the BB line in FIG.</figref>

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the left-right direction in FIG. 1 is the X direction, the vertical direction is the Z direction, and the X direction and the direction orthogonal to the Z direction (front-back direction) are the Y directions.

The drive device 100 according to the present embodiment is a sensor capable of measuring the distortion generated in the drive unit 1 by using light. As shown in FIGS. 1 and 2, the drive device 100 has a drive unit 1 that passively or actively generates distortion based on input energy (power, external force), and a drive unit 1 above the drive unit 1 in the Z direction. The arranged light source 2 and the marker 3 which is integrally formed on the surface of the drive unit 1 by fine processing and reflects the light emitted from the light source 2, and the marker 3 which is arranged above the drive unit 1 in the Z direction and is reflected by the marker 3. It is configured to include a detection unit 4 that detects the emitted light, a signal processing unit 5 that measures the distortion of the drive unit 1 based on the light detected by the detection unit 4, and a control unit 6 (see FIG. 2). ing.

As shown in FIGS. 3 and 4, the drive unit 1 is a member capable of outputting physical quantities such as strain, displacement, and force by inputting power P1. Specifically, as shown in FIG. 4, the drive unit 1 generates a displacement when the power P1 is input, and generates a power-induced force P11 when the displacement occurs. Further, the drive unit 1 generates displacement, power-induced force P2, and the like through distortion. Here, assuming that the amount of displacement (due to power) is Q1, the length before displacement is L1, and the length after displacement is L2, the strain D1 can be expressed by Equation 1. D1 = Q1 / L2 ... (1) Since the displacement amount Q1 is the length after displacement L2 minus the length L1 before displacement, the strain D1 can be expressed by Equation 2. .. D1 = (L2-L1) / L2 ... (2)

FIG. 5 shows an example of the behavior when an external force P2 other than the power P1 is generated in the drive unit 1. Further, FIG. 6 shows side views of the drive units of FIGS. 3 to 5. In the example shown in FIG. 5, an external force P2 is input to the drive unit 1 in addition to the power P1. The external force P2 is energy that causes the drive unit 1 to output distortion / displacement due to factors other than the power P1 such as temperature and load. When an external force P2 is input to the drive unit 1, distortion / displacement is generated in the drive unit 1, and the distortion / displacement is generated to generate a force P21 caused by the external force. Therefore, as shown in FIG. 6, the actual displacement amount Q3 of the drive unit 1 when the external force P2 is generated is expressed by Equation 3 when the displacement amount caused by the power is Q1 and the displacement amount caused by the external force is Q2. be able to. Q3 = Q1 + Q2 ... (3) That is, in order to accurately output the actual displacement amount Q3 of the drive unit 1, it is necessary to detect the displacement amount Q2 caused by the external force. A sensor that detects distortion is needed.

Further, the drive unit 1 is, for example, a member formed of an alloy containing palladium. Palladium is one of the hydrogen storage alloys and can generate the plasmon phenomenon. A hydrogen storage alloy is an alloy capable of causing a volume change (volume increase due to hydrogen adsorption and volume contraction due to hydrogen release) by absorbing and releasing hydrogen corresponding to power P1. That is, the drive unit 1 can output a desired strain amount by controlling the hydrogen amount and temperature of palladium, which is a hydrogen storage alloy.

The light source 2 emits a linearly polarized light flux (incident light 21) toward the marker 3 arranged below. The light source 2 emits a luminous flux having a wavelength of 1 μm or less.

Marker 3 has a nanohole array structure in which uniform pores on the nanometer scale are regularly arranged, in which the light intensity of reflected light fluctuates according to the amount of strain generated by an external force (for example, load, weight, heat, magnetic force, pressure, etc.). have. As shown in FIGS. 7 and 8, the marker 3 includes a first medium 31 and a second medium 32, is integrally formed on the surface of the drive unit 1 by microfabrication, and is emitted from the light source 2. Reflects the luminous flux. The first medium 31 and the second medium 32 have different refractive indexes. The first medium 31 is, for example, a substantially square plate-shaped member formed of an alloy containing palladium. The first medium 31 may be a metal such as aluminum, gold, silver, titanium, titanium oxide, a resin, an oxide semiconductor, or the like. In the first medium 31, a region in which the second medium 32 is housed is formed in a perfect circular shape with the Z direction as the central axis in a plan view. The second medium 32 is formed of a material having an elastic modulus smaller than that of the first medium 31, such as acrylic resin, and is formed in a perfect circular shape with the Z direction as the central axis in a plan view. The second medium 32 is periodically arranged in the first medium 31. Further, the diameter X0 of the second medium 32 is formed to be shorter than the peak wavelength of the light source 2.

The second medium 32 is formed of acrylic resin or the like, but the present invention is not limited to this. For example, the gas may be contained in the region where the second medium 32 is accommodated. In this case, an arbitrary gas may be sealed, or air may be used as the second medium 32 by setting the region of the second medium 32 as a space.

Further, as shown in FIGS. 9 and 10, the first medium 31 and the second medium 32 constituting the marker 3 are deformed by an external force in a direction parallel to the surface of the driving unit 1 (marker 3). .. For example, as shown in FIGS. 9A and 9B, when the marker 3 is distorted / displaced in the X direction (X distortion 711), the marker 3 is distorted / displaced in the X direction. As shown in FIG. 9 (C), the second medium before the strain / displacement of the marker 3 is 320, the second medium after the strain / displacement of the marker 3 is 321 and the second medium before the strain / displacement. Assuming that the diameter of 320 is X0 and the diameter of the second medium 321 after strain / displacement is X1, the strain amount εx generated in the marker 3 can be calculated by the equation (1). Formula (1): εx = (X1-X0) / X0 Further, FIGS. 10 (A) to 10 (C) are diagrams showing that the marker 3 is distorted / displaced in the Y direction when the marker 3 is distorted / displaced in the Y direction (Y distortion 712). is there. As shown in FIG. 10 (C), the second medium before strain / displacement of marker 3 is 320, the second medium after strain / displacement of marker 3 is 321, and the second medium before strain / displacement. Assuming that the diameter of 320 is Y0 and the diameter of the second medium 321 after strain / displacement is Y1, the strain amount εy generated in the marker 3 can be calculated by the equation (2). Formula (2): εy = (Y1-Y0) / Y0

The detection unit 4 detects the light intensity of the luminous flux (reflected light 22) reflected by the marker 3. The light intensity of the reflected light 22 detected by the detection unit 4 is output to the signal processing unit 5.

The signal processing unit 5 calculates the amount of distortion of the drive unit 1 based on the light intensity of the reflected light 22 output from the detection unit 4. Specifically, the signal processing unit 5 calculates the amount of distortion based on the table data (see FIG. 12) showing the correspondence between the light intensity and the amount of distortion.

The control unit 6 is configured to include a CPU, RAM, ROM, etc., and the CPU expands various programs stored in the ROM into RAM and cooperates with the expanded various programs to drive unit 1 and light source 2. , The operation of each part of the drive device 100 such as the detection unit 4 and the signal processing unit 5 is comprehensively controlled (see FIG. 2).

Next, in the drive device 100 according to the present embodiment, a method of calculating the amount of strain generated in the marker 3 (drive unit 1) will be described with reference to FIGS. 11 and 12. The range of the measurable displacement amount depends on the wavelength of the light source 2 and the length of the diameter X0 of the second medium 32. Therefore, by defining the wavelength of the light source 2 and the diameter X0 of the second medium 32 on the nanometer scale, the amount of strain due to the displacement of the nanometer scale can be measured. Of course, it is also possible to measure the amount of strain due to displacement of micrometers or more by appropriately setting the wavelength of the light source 2, the size of the structure, the material, and the like.

<p> In the embodiment, as the marker 3, the thickness Z0 of the first medium 31 is 1000 nm, the thickness Z1 of the second medium 32 is 200 nm, the diameter X0 of the second medium 32 is 300 nm, and the period of the second medium 32. The one with C0 of 450 nm was used. Further, palladium (Pb) was used as the first medium 31, and air was used as the second medium 32. Further, as the light source 2, a light source having linearly polarized light polarized in the X direction, which is the distortion direction of the marker 3, and having a peak wavelength of about 700 nm was used.</p><p> FIG. 11 shows the change in the reflected light spectrum due to the distortion of the marker 3. As shown in FIG. 11, when the marker 3 is distorted, the reflected light intensity of the marker 3 changes depending on the distortion direction (X direction in this embodiment). This is because when the marker 3 is distorted, the shape of the second medium 32 contained in the marker 3 is distorted, and the characteristics (resonance conditions) of the surface plasmon generated on the surface of the marker 3 are changed. That is, there is a correlation between the amount of distortion of the marker 3 and the intensity of the reflected light, and by using this correlation, the amount of distortion of the marker 3 can be calculated from the intensity of the reflected light.</p><p> FIG. 12 is table data showing the correspondence between the amount of distortion of the marker 3 in the X direction and the intensity of reflected light. The reflected light intensity is calculated by "the amount of reflected light 22 ÷ the amount of incident light 21". The example shown in FIG. 12 is a plot of the reflected light intensity at a wavelength of 700 nm for each strain amount. By preparing (inputting) the table data shown in FIG. 12 in advance in the signal processing unit 5, the amount of distortion in the X direction generated in the marker 3 based on the reflected light intensity detected by the detection unit 4 Can be calculated. For example, when the reflected light intensity detected by the detection unit 4 is 0.50, the amount of distortion (0.10) corresponding to the reflected light intensity 0.50 can be calculated by referring to the table data shown in FIG.</p><p> It should be noted that the light source 2 that can be polarized in the distortion direction of the marker 3 is prepared, and the signal processing unit 5 prepares table data in advance for each distortion direction (polarization direction), so that the light source 2 is generated in the marker 3. The amount of distortion in all directions on the XY plane can be calculated. For example, when it is desired to calculate the distortion amount of the marker 3 in the Y direction, a light source 2 that linearly polarizes in the Y direction is prepared, and the signal processing unit 5 determines the distortion amount of the marker 3 in the Y direction and the reflected light intensity. By preparing table data in which the correspondence is plotted in advance, it is possible to calculate the amount of distortion of the marker 3 in the Y direction.</p><p> Next, the operation of the drive device 100 according to the present embodiment will be described with reference to the flowchart of FIG. First, the control unit 6 controls the detection unit 4 to detect the spectral intensity of the luminous flux (reflected light 22) reflected by the marker 3 (step S101). Next, the control unit 6 controls the signal processing unit 5 to calculate the amount of distortion generated in the marker 3 from the spectral intensity detected in step S101 (step S102).</p><p> Next, the control unit 6 determines whether or not the strain amount calculated in step S102 is a predetermined strain amount set in advance (step S103). The predetermined strain amount is a strain amount caused by power desired by the user, and is appropriately set according to the material and the like of the drive unit 1. When the control unit 6 determines that the amount of distortion is a predetermined amount (step S103: YES), the control unit 6 ends the process. On the other hand, when it is determined that the strain amount is not the predetermined strain amount (step S103: NO), the control unit 6 controls the input value of the drive unit 1 based on the strain amount calculated in step S102 (step S104). Here, the input value of the drive unit 1 is the value of the power P1 input to the drive unit 1. That is, the control unit 6 controls the drive unit 1 to output a predetermined amount of distortion by controlling the value of the power P1 input to the drive unit 1. That is, the control unit 6 functions as the distortion control unit of the present invention. The control unit 6 controls the input value of the drive unit 1 in step S104, then proceeds to step S101, and repeats the process again. By the above processing, the drive unit 1 can output a predetermined amount of distortion.</p><p> As described above, the drive device 100 according to the present embodiment includes at least a drive unit 1 that includes a material that generates plasmons and causes distortion based on the input energy, and a light source 2 that emits light. , A detection that is formed on the surface of the drive unit 1 and causes distortion due to deformation of the drive unit 1 and detects the light intensity of the light reflected by the marker 3 and the marker 3 that reflects the light emitted from the light source 2. Distortion of the drive unit 1 based on the strain amount calculated by the signal processing unit 5 and the signal processing unit 5 that calculates the amount of distortion generated in the marker 3 based on the light intensity detected by the unit 4 and the detection unit 4. It includes a strain control unit (control unit 6) that controls the amount. Further, the marker 3 has a periodic fine structure equal to or less than the wavelength of the light emitted from the light source 2 on the surface of the drive unit 1. Therefore, according to the drive device 100 according to the present embodiment, the distortion can be detected based on the change in the reflection intensity of light, so that the distortion can be detected at high speed without requiring a complicated process such as image analysis. can do. Further, since the surface of the drive unit 1 itself is provided with a fine structure, the marker 3 is not damaged or peeled off even when an impact is generated by an external force or the like, and strain is stably detected. be able to. Therefore, according to the drive device 100 according to the present embodiment, distortion can be detected while simultaneously satisfying high-speed detectability and high impact resistance.</p><p> Further, according to the drive device 100 according to the present embodiment, the drive unit 1 and the marker 3 are made of a material containing at least a hydrogen storage alloy. Therefore, according to the drive device 100 according to the present embodiment, since complicated parts such as gears, compressors, and motors are unnecessary, the configuration of the drive unit 1 can be miniaturized. Further, since the hydrogen adsorption alloy can generate plasmons, it is possible to detect minute strains in the drive unit 1 simply by forming a μm-sized marker 3 on the surface of the drive unit 1. Therefore, according to the drive device 100 according to the present embodiment, it is possible to feed back the distortion to the control unit 6 while realizing the miniaturization of the drive unit 1.</p><p> Further, according to the drive device 100 according to the present embodiment, the hydrogen storage alloy is an alloy containing palladium. Therefore, according to the drive device 100 according to the present embodiment, the volume expansion coefficient of palladium reaches about 300% by absorbing hydrogen, so that a large force (strain) can be output as the drive unit 1. Further, since palladium generates surface plasmons in the visible light region, distortion of the drive unit 1 can be easily detected. Therefore, according to the drive device 100 according to the present embodiment, the output function of the drive unit 1 and the distortion detection function can be compatible at a high level.</p><p> Further, according to the drive device 100 according to the present embodiment, the marker 3 is integrated with the drive unit 1. Therefore, according to the drive device 100 according to the present embodiment, the elastic coefficients of the drive unit 1 and the marker 3 can be matched, so that stress is generated between the drive unit 1 and the marker 3 even when the drive unit 1 is deformed. Can be suppressed, and breakage and deterioration of the marker 3 can be suppressed. Further, since it is not necessary to attach and fix the marker 3, it is possible to eliminate the concern that the marker 3 will be peeled off, and it is possible to realize cost reduction due to reduction of fixing members and processes.</p><p> Further, according to the driving device 100 according to the present embodiment, the marker 3 is formed in a flat plate shape having a first medium 31 and a second medium 32 having different refractive indexes. Further, the second medium 32 is periodically arranged in the first medium 31, and the maximum length in the direction parallel to the light receiving surface of the marker 3 of the second medium 32 is the light emitted from the light source 2. It is formed so as to be shorter than the wavelength of. Therefore, according to the drive device 100 according to the present embodiment, the shape of the second medium 32 included in the marker 3 is distorted, and the light intensity of the light reflected by the marker 3 changes. Therefore, the detected light intensity is distorted. By converting to, the magnitude of distortion generated in the drive unit 1 can be detected. Moreover, since the range of the amount of displacement that can be detected depends on the wavelength of the light source 2 and the length of the diameter of the second medium 32, the wavelength of the light source 2 and the length of the diameter of the second medium 32 are set to the nanometer scale. By specifying, distortion due to displacement on the nanometer scale can be detected. Of course, by appropriately setting the wavelength of the light source 2, the size of the structure, the material, etc., it is possible to measure the strain due to the displacement of micrometers or more.</p><p> Further, according to the drive device 100 according to the present embodiment, the gas is accommodated in the region where the second medium 32 is accommodated. Therefore, according to the drive device 100 according to the present embodiment, stress or the like is not generated between the first medium 31 and the second medium 32, so that robustness against repeated deformation can be ensured.</p><p> Although the specific description has been given above based on the embodiment of the present invention, the present invention is not limited to the above embodiment and can be changed without departing from the gist thereof.</p><p>(Modified Example) For example, in the example shown in FIG. 14, the configurations of the light source 2A, the detection unit 4A, and the signal processing unit 5A are different from those of the driving device 100 of the embodiment. For the sake of simplification of the description, the same components as those in the embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.</p><p> Specifically, as shown in FIG. 14, the light source 2A of the driving device 100A according to the modified example emits a plurality of different linearly polarized light fluxes (incident light 21A) toward the marker 3 arranged below. Each incident light 21A is polarized in a direction parallel to the light receiving surface of the marker 3. The detection unit 4A detects the light intensity and the polarization direction of the light flux (reflected light 22A) reflected by the marker 3. The signal processing unit 5A calculates the distortion direction and the amount of distortion of the drive unit 1 based on the light intensity and the polarization direction of the reflected light 22A output from the detection unit 4A. Specifically, the signal processing unit 5A calculates the amount of distortion based on the table data showing the correspondence between the calculated light intensity and the amount of distortion in the distortion direction.</p><p> As described above, according to the driving device 100A according to the modified example, the light source 2A emits a plurality of lights polarized in a direction parallel to the light receiving surface of the marker 3, each having a different polarization direction. Further, the detection unit 4A further detects the polarization direction of the light reflected by the marker 3, and the signal processing unit 5A further detects the distortion generated in the marker 3 based on the light intensity and the polarization direction detected by the detection unit 4A. Calculate the direction. Therefore, according to the driving device 100A according to the modified example, since the reflected light intensity in a plurality of polarization directions can be detected, the maximum distortion direction can be detected based on the difference in the light intensity in each polarization direction. Further, the amount of distortion in the maximum distortion direction can be detected based on the detected light intensity in the maximum distortion direction. Therefore, according to the drive device 100A according to the modified example, the distortion of the drive unit 1 can be acquired as two-dimensional information.</p><p>(Other Modifications) Further, in the above embodiment, in the marker 3, the second medium 32 is arranged in a grid pattern in the first medium 31, but the present invention is not limited to this. For example, as in the marker 3A shown in FIG. 15, the second medium 32 may be arranged so as to be shifted by δy in the Y direction with the second medium 32 adjacent in the X direction.</p><p> In the marker 3A, the deformation direction and the periodic direction of the second medium 32 are not parallel to each other because the first medium 31 and the second medium 32 are arranged as described above. Therefore, when an arbitrary cross section is cut out in the direction parallel to the deformation direction (X direction in the figure), the area ratios of the media (first medium 31 and second medium 32) for each cross section are substantially the same. It has become. For example, as shown in FIGS. 15 to 17, when the cross section of the AA line (A cross section; see FIG. 16) and the cross section of the BB line (B cross section; see FIG. 17) in FIG. 15 are compared, the area of the medium. The ratio is almost the same. As described above, the fact that the area ratio of the medium is substantially the same for each cross section means that the apparent elastic modulus for each cross section is substantially the same. It is most preferable that the marker 3A has the same area ratio of the medium for each cross section in the direction parallel to the deformation direction, but the marker 3A is not limited to this. That is, if the configuration is such that at least one second medium 32 exists in the direction parallel to the deformation direction, the variation in the area ratio of the medium for each cross section can be alleviated. Therefore, the marker 3A It is possible to alleviate the variation in the apparent elastic modulus for each location.</p><p> As described above, by arranging the second medium 32 in the direction parallel to the deformation direction of the marker 3A so that at least one exists, the second medium 32 is arranged in the direction parallel to the distortion direction (deformation direction) of the marker 3A. Since the variation in the area ratio of the medium for each cross section can be alleviated, the variation in the apparent elastic modulus for each location of the marker 3A can be alleviated. Therefore, the upper limit of the amount of distortion that can be detected by the marker 3A can be increased.</p><p> Further, in the above embodiment, the first medium 31 of the drive unit 1 and the marker 3 is formed of an alloy containing palladium, but the present invention is not limited to this. For example, the first medium 31 of the drive unit 1 and the marker 3 may be formed of a hydrogen storage alloy other than palladium instead of palladium. Further, the first medium 31 of the drive unit 1 and the marker 3 may be formed of a metal other than the hydrogen storage alloy (for example, a magnetic shape memory alloy or the like).</p><p> Further, in the above embodiment, the marker 3 is integrally formed on the surface of the drive unit 1, but the present invention is not limited to this. For example, the marker 3 may be formed separately from the drive unit 1, and the marker 3 and the drive unit 1 may be welded to each other. As described above, by forming the marker 3 separately from the drive unit 1, the marker 3 can be easily molded, so that the time and cost required for the molding work can be reduced.</p><p> The drive unit of the present invention includes a member (for example, a transmission member) attached to the drive unit 1. That is, the marker 3 may be formed on the surface of a member attached to the drive unit 1. As a result, even when the marker 3 is indirectly arranged with respect to the drive unit 1, distortion can be detected while simultaneously satisfying high-speed detectability and high impact resistance.</p><p> Further, in the above embodiment, the region in which the second medium 32 is housed is formed in a perfect circular shape with the Z direction (the direction orthogonal to the light receiving surface of the marker 3) as the central axis in a plan view. However, it is not limited to this. That is, any shape may be used as long as the maximum length in the direction parallel to the light receiving surface of the marker 3 is shorter than the wavelength of the light emitted from the light source 2, for example, an elliptical shape or a rectangular shape. There may be.</p><p> Further, in the above embodiment, as the second medium 32, a material having an elastic modulus smaller than that of the first medium 31 is used, but the present invention is not limited to this. That is, as the second medium 32, it is more preferable to use a material having an elastic modulus smaller than that of the first medium 31, but rather than a material having an elastic modulus equivalent to that of the first medium 31 or the first medium 31. It is also possible to use a material having a large elastic modulus.</p><p> Further, in the above embodiment, the strain amount is calculated based on the table data (see FIG. 12) showing the correspondence between the light intensity and the strain amount, but the present invention is not limited to this. For example, it may be calculated by a predetermined calculation formula based on the light intensity detected by the detection unit 4.</p><p> Further, in the above embodiment, the configuration in which the light flux emitted from the light source 2 is reflected by the marker 3 is illustrated and described, but the present invention is not limited to this. For example, by making the marker 3 and the driving unit 1 transparent, the light flux emitted from the light source 2 may be transmitted through the marker 3 and the driving unit 1. In this case, the detection unit 4 is arranged at the point where the light flux emitted from the light source 2 passes through the marker 3 and the drive unit 1, and detects the spectral intensity of the light transmitted by the marker 3. As a result, the amount of distortion can be measured using the light transmitted through the marker 3 and the driving unit 1, so that the measurement accuracy can be further improved as compared with the measurement using the reflected light.</p><p> Further, a temperature measuring unit for measuring the temperature of the marker 3 and the driving unit 1 is provided, and the signal processing unit 5 calculates the Young's modulus of the marker 3 and the driving unit 1 based on the temperature measured by the temperature measuring unit. You may try to do it. As a result, the measured value can be corrected based on the calculated Young's modulus, so that the measurement accuracy of the strain amount can be further improved.</p><p> Further, in the above embodiment, as shown in FIG. 1, the light source 2 and the detection unit 4 are arranged apart from each other, but the present invention is not limited to this. That is, the light source 2 and the detection unit 4 may be arranged adjacent to each other, and the light source 2 may emit light in a direction substantially perpendicular to the light receiving surface of the marker 3. As a result, the luminous flux can be incident substantially perpendicular to the marker 3, so that the variation in the spectral intensity due to the incident angle of the luminous flux can be suppressed as much as possible, and the stability of the measurement accuracy of the strain amount can be ensured. ..</p><p> In addition, the detailed configuration of each device constituting the drive device and the detailed operation of each device can be appropriately changed without departing from the spirit of the present invention.</p>

100, 100A Drive device 1 Drive unit 2, 2A Light source 21, 21A Incident light 22, 22A Reflected light 3, 3A Marker 31 First medium 32 Second medium 4, 4A Detection unit 5, 5A Signal processing unit 6 Control unit (Distortion control unit)