JP2006340944A - Large deformation sensor, and seated person behavior detection sensor/monitor and game/exercising apparatus using the large deformation sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a large deformation sensor which is inexpensive and compact to be easy to use and which can detect extending deformation and contracting deformation of several tens percent or larger, and to provide a seated person behavior detection sensor/monitor and a game/exercising apparatus which use the large deformation sensor and which are suitable for detecting the action and behavior of the person. <P>SOLUTION: The large deformation sensor consists of: an elastic band; and a piezoelectric film outputting a signal according to the strain in the longitudinal direction of the elastic band. The large deformation sensor consists of: an elastic band having a Young's modulus of 0.5 to 10MPa; and a pair of piezoelectric films arranged separately in the longitudinal direction of the elastic band and outputting a signal according to the strain in the longitudinal direction of the elastic band. The seated person behavior detection sensor/monitor and the game/exercising apparatus are constituted using them. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a large deformation sensor using a piezoelectric film, and a seat occupant behavior detection sensor / monitor device and a game / training device suitable for detecting a motion and behavior of a person using the same.

  A strain gauge is usually used to detect elongation deformation and shrinkage deformation of several percent or less. In addition, since the strain gauge has no durability for detecting elongation deformation and contraction deformation exceeding 10 percent, a laser displacement meter, for example, that does not use an elastic body that is a measure of strain measurement such as a strain gauge is used. There are many cases.

  However, there is a problem that such an apparatus for measuring the elongation and the like with high accuracy without contact is generally expensive and large. For this reason, there are few attempts to develop a strain gauge that is inexpensive, compact, and easy to use, and that can detect strain deformation and contraction deformation more than conventional strain gauges. For example, Patent Document 1 proposes a strain sensor using a superelastic alloy foil which is a Cu—Al—Mn alloy and whose electric resistance changes linearly in proportion to the strain, and this allows a maximum of 35%. It is disclosed that large deformations of wood, concrete, resin and the like can be measured repeatedly.

Japanese Patent Laid-Open No. 2004-10999

  However, there is no proposed example of a large deformation sensor capable of detecting strain deformation or deformation deformation more than that proposed in Patent Document 1 with a sensor capable of detecting strain-type or strain gauge-like contact-type stretch or shrink deformation. .

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a contact-type large deformation sensor that is inexpensive, compact, easy to use, and capable of detecting expansion deformation or contraction deformation of several tens percent or more. . It is another object of the present invention to provide a seat occupant behavior detection sensor / monitoring device and a game / training device suitable for detecting a human motion and behavior using the large deformation sensor.

  The large deformation sensor according to the present invention includes an elastic band and a piezoelectric film that outputs a signal corresponding to the strain in the longitudinal direction of the elastic band.

In the elastic band and the piezoelectric film of the large deformation sensor, the elastic band and the piezoelectric film preferably have an elongation rigidity E × A that satisfies the following expression (1). Here, E ₁ and E ₂ are Young's moduli of the piezoelectric film and the elastic band, respectively, and A ₁ and A ₂ are the cross-sectional area of the piezoelectric film in the cross section including the piezoelectric film and the crossing of the elastic band, respectively. It is an area. (E ₁ × A ₁ ) / (E ₂ × A ₂ ) = 3 to 300 (1)

The large deformation sensor according to the present invention includes an elastic band, a piezoelectric film that outputs a signal corresponding to the strain in the longitudinal direction of the elastic band, and an elastic member that covers the piezoelectric film and deforms integrally with the elastic band. The large deformation sensor satisfying the following expression (2) can be obtained. Here, E ₁ is the Young's modulus of the piezoelectric film, E ₂ is the Young's modulus of the elastic band, and E ₃ is the Young's modulus of the elastic member. E ₂ ≦ E ₃ <E _l (2)

In the elastic band, the piezoelectric film, and the elastic member of the large deformation sensor, it is preferable that the elongation rigidity E × A of the elastic band, the piezoelectric film, and the elastic member satisfy the following expression (3). Here, E ₁ , E ₂ , and E ₃ are Young's moduli of the piezoelectric film, elastic band, and elastic member, respectively, and A ₁ , A ₂ , and A ₃ are transverse sections including the piezoelectric film and elastic member of the elastic band. The cross-sectional area of each surface of the piezoelectric film, the cross-sectional area of the elastic band, and the cross-sectional area of the elastic member. _{(E 1 × A 1 + E} 3 × A 3) / (E 2 × A 2) = 3~300 (3)

  The large deformation sensor according to the present invention further includes an elastic band and a pair of piezoelectric films that are arranged in the longitudinal direction of the elastic band and output a signal corresponding to the strain in the longitudinal direction of the elastic band. .

In addition, a large deformation sensor according to the present invention includes an elastic band, a pair of piezoelectric films that are spaced apart in the longitudinal direction of the elastic band and output a signal corresponding to the strain in the longitudinal direction of the elastic band, It consists of an elastic member that covers a pair of piezoelectric films and deforms integrally with the elastic band, and satisfies the following formula (4). Here, E ₂ is the Young's modulus of the elastic band, E ₁ is the Young's modulus of the piezoelectric film, and E ₃ is the Young's modulus of the elastic member. E ₂ ≦ E ₃ <E _l (4)

  In the large deformation sensor, an elastic band having a Young's modulus of 0.5 to 10 MPa is preferably used, and an elastic member having a Young's modulus of 0.5 to 10 MPa is preferably used.

  The large deformation sensor according to the present invention is also provided with an elastic band having a Young's modulus of 0.5 to 10 MPa and a signal corresponding to the strain in the longitudinal direction of the elastic band which is arranged in the longitudinal direction of the elastic band. A pair of piezoelectric films and a support member for stretching the elastic band, and by disposing the large deformation sensor on or in the seat body, It is possible to configure a behavior detection sensor that can detect.

Moreover, a seat occupant's state monitoring apparatus can be comprised using the said behavior sensor. That is, the behavior detection sensor, the measurement means for the output signals V _l and V ₂ of the pair of piezoelectric films of the behavior detection sensor, the phase calculation means for V _l and V ₂ measured by the measurement means, and V _l Thus, a seat occupant state monitoring device comprising V ₂ addition and subtraction calculation means and determination means for determining the weight of the seat occupant and the center of gravity position of the seat occupant from the calculation result of the calculation means can be configured.

Further, the behavior detection sensor, the measurement means for the output signals V _l and V ₂ of the pair of piezoelectric films of the behavior detection sensor, the phase calculation means for V _l and V ₂ measured by the measurement means, and V _l Thus, a seat occupant state monitoring device comprising a subtraction value differential calculation means for V ₂ and a determination means for determining the movement speed of the position of the occupant from the calculation result of the calculation means can be configured.

  Furthermore, the present invention can constitute a game / training apparatus that can play or train with interest or motivation for the following users. That is, an elastic band having a Young's modulus of 0.5 to 10 MPa, a pair of piezoelectric films that are spaced apart in the longitudinal direction of the elastic band and output a signal corresponding to the strain in the longitudinal direction of the elastic band, and the elastic The pair of piezoelectric films comprises: a support member that fixes both ends of the band; signal processing means that processes signals from the pair of piezoelectric films; and display means that displays signals processed by the signal processing means. A game / training apparatus in which a load acting part from a player or a trainee is provided in the elastic band portion between the two can be configured.

  In the game / training apparatus, the signal processing means calculates the magnitude and timing of the force applied to the deformation sensor by the player from the measurement means for measuring the signal from the piezoelectric film and the measurement value measured by the measurement means. The calculation means, a database storing training programs, and comparison means for comparing the data stored in the database with the results of the calculation means can be used.

  The display means can display the result of the calculation means and the result of the comparison means, and can display the training degree to the trainee. The game / training apparatus includes a player or trainer. It is preferable to provide an input means for inputting a signal from the computer and an interrupt means for processing the signal from the input means and inputting the signal to the signal processing means of the game / training apparatus.

  The large deformation sensor according to the present invention is inexpensive, compact and easy to use, and can detect elongation deformation and contraction deformation of several tens of percent or more. Further, it is possible to configure a seat occupant behavior detection sensor / monitor device and a game / training device suitable for detecting a human motion and behavior using the large deformation sensor.

  Embodiments of a large deformation sensor according to the present invention will be described below with reference to the drawings. 1A and 1B are schematic views showing the configuration of a large deformation sensor 100 according to the present invention, in which FIG. 1A is a plan view, and FIG. 1B is an enlarged cross-sectional view taken along line AA in FIG. FIG. 2 is an electric circuit diagram for measuring a large deformation amount and the like using the large deformation sensor 100. FIG.

  The large deformation sensor 100, as shown in FIG. 1, is a piezoelectric film that outputs a signal corresponding to the long elastic band 15 and the strain in the longitudinal direction of the elastic band, that is, embedded in the substantially central portion of the elastic band 15. The piezoelectric film 10 and a pair of electrodes 13 (13A, 13B) provided on the front and back surfaces of the piezoelectric film 10 for taking out an electric charge generated in the piezoelectric film 10 according to the longitudinal strain of the elastic band 15 as an output voltage ).

  As the piezoelectric film 10, a known film can be used. For example, PVDF (polyvinylidene fluoride) having a film thickness of 20 to 100 μm, Young's modulus of 2000 to 4000 MPa, and Poisson's ratio of 0.3 to 0.35 can be used. A laminate of PVDF can also be used.

  The pair of electrodes 13 (13A, 13B) provided on both surfaces of the piezoelectric film 10 can be configured by vapor-depositing aluminum on both surfaces of the piezoelectric film 10, applying a conductive paint, or sputtering of copper or nickel. The electrodes 13A and 13B may be any electrode as long as they can follow the deformation of the piezoelectric film 10 without hindering the deformation and have excellent conductivity. Further, the electrodes 13A and 13B should not be short-circuited at the peripheral edge portion and may extend over almost the entire surface of the piezoelectric film 10. Thereby, an output voltage corresponding to the area of the piezoelectric film 10 can be obtained.

  As the elastic band 15, an elastic body having an elastic elongation of several tens of percent or more is used. For example, various rubber materials such as natural rubber and synthetic rubber, or a flexible elastic body formed by combining various rubber materials can be used.

  In the large deformation sensor 100, the shape and layout of the cross section of the piezoelectric film 10 (including the electrode 13) and the elastic band 15 are important because they are related to the measurement accuracy such as the deformation amount. That is, the cross-sectional shapes of the piezoelectric film 10 and the elastic band 15 are symmetric with respect to the YY axis and the ZZ axis orthogonal to each other, as shown in FIG. It is preferable that the elastic band 15 is embedded inside the elastic band 15 so that the symmetry axis of the cross section of the elastic band 15 coincides with the symmetry axis of the elastic band 15. As a result, when the large deformation sensor 100 receives a bending force in the out-of-plane direction, the output voltage does not fluctuate due to the bending force in the piezoelectric film 10, so that highly accurate measurement is possible. In addition, when the large deformation sensor 100 receives an external force in the longitudinal direction, the piezoelectric film 10 is not subjected to out-of-plane bending deformation, so that highly accurate measurement is possible.

  In addition, the cross sections of the piezoelectric film 10 and the elastic band 15 are preferably uniform in the longitudinal direction of the elastic band 15. That is, the cross section of the elastic band 15 including the piezoelectric film 10 and the cross section of the portion not including the piezoelectric film 10 may be uniform in the longitudinal direction of the elastic band 15, respectively. This makes it easy to ensure high measurement accuracy. Also, it becomes easy to manufacture a large deformation sensor.

  Note that the layout position of the piezoelectric film 10 in the longitudinal direction of the elastic band 15 does not necessarily have to be approximately the center of the elastic band 15. The external force loaded on the elastic band 15 may be at a position where it is transmitted to the piezoelectric film 10.

As shown in FIG. 2, an electric circuit diagram for measuring a large deformation amount or the like using the large deformation sensor 100 includes a piezoelectric film 10 and wirings 18 (18A, 18B) for guiding charges generated inside the piezoelectric film 10 to the outside. ) And the circuit of the voltage detection device 60 that detects the electric charge generated in the piezoelectric film 10 as an output voltage. In FIG. 2, R ₀ indicates the internal resistance of the voltage detection device 60. Capacitance C and resistance R are a capacitor and a resistance provided in a circuit on the deformation sensor 100 side or the voltage detection device 60 side as needed depending on the load speed of the external force.

  The wiring 18 (18A, 18B) is configured by soldering the wiring to a metal foil tape with a conductive adhesive, for example, and bonding the adhesive surface of the metal foil tape to the electrodes 13A, 13B or by caulking. . These end portions are connected to a wiring connector (not shown) so that they can be easily connected to the wiring connector of the voltage detection device 60. In addition, about the piezoelectric film demonstrated below, when the output voltage is concerned, it shall have a pair of electrodes and the wiring connected to this on the front and back of a piezoelectric film.

The capacitor C provided on the voltage detection device 60 side is preferably 0.2 to 2 μF when PVDF is used for the piezoelectric film 10. The resistor R is generally provided when the load speed of the external force is moderate and the period of the output voltage detected from the piezoelectric film 10 is long. For example, it is preferable to provide a resistor R in the circuit on the voltage detection device 60 side so that the combined resistance (R ₀ + R) is 1 to 10 MΩ.

Next, the principle of measuring the large deformation amount (elongation) using the large deformation sensor 100 will be described below. Consider a case where an external force W is acting on the large deformation sensor 10 as shown in FIG. The elastic band 15 and the piezoelectric film 10 have a uniform shape in the longitudinal direction of the elastic band 15, and the cross-sectional shapes of the piezoelectric film 10 and the elastic band 15 in the cross section of the elastic band 15 including the piezoelectric film 10 are symmetrical. Both have the same axis of symmetry. The total length of the elastic band 15 is L (mm), and the length of the piezoelectric film 10 is L _l (mm). The strain of the cross section of the elastic band 15 including the piezoelectric film 10 is ε, the transverse area of the piezoelectric film 10 is A ₁ , and the transverse area of the elastic band is A ₂ . The Young's modulus of the piezoelectric film 10 is E ₁ , and the Young's modulus of the elastic band is E ₂ . Further, the elongation of the large deformation sensor 100 is represented by δ.

In the large deformation sensor 100 described above, the external force W is borne by the elastic band 15 and the piezoelectric film 10 in a shared manner. Further, the elongation δ of the large deformation sensor 100 is the elongation L ₁ × ε of the elastic band portion including the piezoelectric film (the piezoelectric film 10 and the elastic band 15 are deformed integrally, so that both strains are equal ε), Since it is the sum of the stretch of the elastic band 15 not including the piezoelectric film 10, the following equation is established according to the elastic material dynamics.

(Equation 1)
W = (E ₁ × A ₁ + E ₂ × A ₂ ) × ε (10)

(Equation 2)
δ = (L ₁ × ε) + (LL ₁ ) × W / (E ₂ × A ₂ )
= (L + (LL ₁ ) × (E ₁ × A ₁ ) / (E ₂ × A ₂ )) × ε (11)

On the other hand, an output voltage V proportional to the strain ε of the piezoelectric film 10 and the area S of the electrode 13 provided on the front and back surfaces of the piezoelectric film 10 can be obtained from the piezoelectric film 10. That is, the output voltage V (volt) is expressed as shown in Equation (12). In the equation (12), k was 0.0 = 97 V / mm ² in the case of a piezoelectric film made of PVDF having a thickness of 40 μm.

(Equation 3)
V = k × S × ε (k is a proportional constant) (12)

According to the above equations (10) to (12), by measuring the output voltage V from the piezoelectric film 10, the magnitude or elongation δ or deformation amount of the external force W can be measured. Further, as shown in the equation (11), the length L of the elastic band 15 is long, and the value of (E ₁ × A ₁ ) / (E ₂ × A ₂ ) (the elongation rigidity ratio of the piezoelectric film 10 to the elastic band 15) It can be seen that the larger the δ, the larger the elongation δ can be measured. The value of (E ₁ × A ₁ ) / (E ₂ × A ₂ ) is preferably 3 to 300. When the value of (E ₁ × A ₁ ) / (E ₂ × A ₂ ) is less than 3, the large deformation sensor 100 has no advantage that it can measure a larger elongation than an elongation measurement sensor using a strain gauge. Because. On the other hand, if the value of (E ₁ × A ₁ ) / (E ₂ × A ₂ ) exceeds 300, the rigidity of the elastic band 15 is too low to be suitable for practical use.

The elongation stiffness ratio (E ₁ × A ₁ ) / (E ₂ × A ₂ ) is, for example, when using a PVDF piezoelectric film 10 having a thickness of 40 μm, a width of 20 mm, and a Young's modulus of 3000 MPa, the elongation stiffness is 2400 N. Therefore, if black natural rubber having a thickness of 1 mm, a width of 20 mm, and an initial Young's modulus of about 3.3 Mpa, or amber rubber having an initial Young's modulus of about 1.0 Mpa is used, the values become 36.4 and 120, respectively. In general, it is preferable to use an elastic band 15 having a Young's modulus of 0.5 to 10 MPa in order to ensure practical rigidity and to enable measurement of large elongation. In the large deformation sensor 100, it can be understood that the external force is mainly borne by the piezoelectric film 10 because the elongation rigidity of the piezoelectric film 10 is considerably larger than the elongation rigidity of the elastic band 15. A sensor that measures strain, elongation, or external force in the form of the large deformation sensor 100 is different from a sensor that uses a conventional strain gauge or the like.

  FIG. 3 shows test results obtained by applying an external force to both ends of the large deformation sensor 100 and measuring the elongation thereof. The test was performed on three types of large deformation sensors A, B, and C having different elastic band 15 materials. The horizontal axis of the graph in FIG. 3 indicates the elongation δ of the large deformation sensor 100, and the vertical axis indicates the output voltage V from the piezoelectric film 10. The parentheses in the parameters indicate the material of the elastic band 15. For each large deformation sensor A, B and C, 40% elongation was repeated 5000 times, and the reproducibility of this test was very high.

  According to FIG. 3, it can be seen that the elongation of up to about 50% can be measured with high accuracy for any of the large deformation sensors A, B, and C, and a greater elongation can be measured than the elongation measurement sensor using a strain gauge.

The test shown in FIG. 3 was performed according to the following procedure. The large deformation sensor used for the test was prepared as follows. First, three types of black natural rubber (initial Young's modulus about 3.3Mpa), silicone rubber (initial Young's modulus about 1.5Mpa), and rubber rubber (initial Young's modulus about 1.0Mpa) with a thickness of 1mm, width of 30mm, and length of 300mm Two elastic bands each were prepared, and each of the two was stacked, and at the center of the elastic band in the longitudinal direction, 0.04mm in thickness, 30mm in width, 30mm in length, and aluminum deposited on the entire front and back surfaces PVDF piezoelectric film (with a Young's modulus of 3000 Mpa) is attached, and the two elastic bands facing each other and the piezoelectric film's front and back surfaces and the elastic band facing each other are all bonded with a rubber adhesive. Large deformation sensors A, B, and C were used respectively. The elongation rigidity ratios (E ₁ × A ₁ ) / (E ₂ × A ₂ ) of these large deformation sensors were 18.2, 40, and 60, respectively.

The three types of large deformation sensors A, B, and C created as described above are each mounted on a servo fatigue tester with an effective length L between chucks of L = 120 mm, and repeatedly subjected to one-way swing displacement (frequency 0.5 Hz). Then, the displacement fluctuation range was gradually increased, and the output voltage of the piezoelectric film was measured with an Omniace type voltage recorder (internal resistance R ₀ = 1 MΩ) manufactured by NEC Sanei Co., Ltd. In this test, including the following test, the capacitor C (0.47 μF) shown in FIG. 2 was provided, but the internal resistance of the voltage detection device 60 was R ₀ = 1 MΩ, so the resistance R was not provided. It was.

  As described above, the large deformation sensor 100 can measure large elongation with high accuracy. However, the large deformation sensor according to the present invention is not limited to the above-described embodiment. That is, the large deformation sensor can have the structure shown in FIG. 4A is a plan view schematically showing the structure of the large deformation sensor 110, and FIG. 4B is an enlarged cross-sectional view taken along the line AA in FIG. 4A.

As shown in FIG. 4, the large deformation sensor 110 includes an elastic band 15, a piezoelectric film 10 that outputs a signal corresponding to the strain in the longitudinal direction of the elastic band 15, and the piezoelectric film 10 that covers the piezoelectric film 10 and is integrated with the elastic band 15. The elastic member 20 is deformed. When the Young's moduli of the elastic band 15, the elastic member 20, and the piezoelectric film 10 are E ₂ , E ₃ , and E ₁ , respectively, the relationship is E ₂ ≦ E ₃ <E _l .

The large deformation sensor 110 is different from the large deformation sensor 100 described above in that the elastic member 20 is provided so as to cover the piezoelectric film 10 and the elastic band 15 portion into which the piezoelectric film 10 is inserted. Although the Young's modulus E ₂ of the Young's modulus E ₁ and the elastic band 15 of the large deformation sensor 110 also piezoelectric film 10 are those having E ₂ <E _l the relationship as described above, large deformation sensor 110 in yet relationship between the elastic member 20, when the Young's modulus of the elastic member 20 and E _3, are those having E ₂ ≦ E ₃ <E _l the relationship. The piezoelectric film 10, the elastic band 15, and the pair of electrodes 13 (13A, 13B) provided on the front and back surfaces of the piezoelectric film 10 can be the same as those of the large deformation sensor 100.

When the large deformation sensor 110 receives an external force W in the longitudinal direction of the elastic band 15 as shown in FIG. 4, the elongation generated in the large deformation sensor 110 is δ, and the elastic band including the piezoelectric film 10 and the elastic member 20 Assuming that the distortion of the 15 portion is ε, the following equation is established as in the case of FIG. Here, the Young's modulus of the piezoelectric film 10, the elastic band 15, and the elastic member 20 is E ₁ , E ₂ , and E ₃ , respectively, and the piezoelectric film in the cross section of the elastic band 15 portion including the piezoelectric film 10 and the elastic member 20 The cross-sectional area of 10 is A ₁ , the cross-sectional area of the elastic band 15 is A ₂ , and the cross-sectional area of the elastic member 20 is A ₃ .

(Equation 4)
W = (E ₁ × A ₁ + E ₂ × A ₂ + E ₃ × A ₃ ) × ε (13)

(Equation 5)
δ = (L ₁ × ε) + (LL ₁ ) × W / (E ₂ × A ₂ )
= (L + (LL ₁ ) × (E ₁ × A ₁ + E ₃ × A ₃ ) / (E ₂ × A ₂ )) × ε (14)

(Equation 6)
V = k × S × ε (k is a proportional constant) (15)

In this large deformation sensor 110, as can be seen from the equation (14), the value of the elongation stiffness ratio (E ₁ × A ₁ + E ₃ × A ₃ ) / (E ₂ × A ₂ ) is the same as the large deformation sensor 100. It can be seen that the larger the δ, the larger the elongation δ can be measured. The elongation stiffness ratio (E ₁ × A ₁ + E ₃ × A ₃ ) / (E ₂ × A ₂ ) is preferably 3 to 300, as in the large deformation sensor 100, and the elastic member 20 is 0.5. It is preferable to have a Young's modulus of ˜10 MPa.

Further, the higher the elongation rigidity (E ₃ × A ₃ ) of the elastic member 20, the smaller the distortion of the large deformation sensor 110 in the portion where the piezoelectric film 10 is inserted, and the elastic member 20 has an effect of suppressing the elongation of the piezoelectric film 10. I understand that there is. The large deformation sensor 110 can measure a larger elongation due to the effect of suppressing the elongation and the effect of preventing the deformation of the piezoelectric film 10 of the elastic member 20 described below.

  Hereinafter, the effect of preventing excessive deformation of the piezoelectric film 10 included in the elastic member 20 will be described. FIG. 5 schematically shows the deformation state of the elastic band 15 in the piezoelectric film 10 portion of the large deformation sensor 100 without the elastic member 20. As described above, the elongation stiffness of the piezoelectric film 10 is much larger than the elongation stiffness of the elastic band 15, so that when the large deformation sensor 100 receives an external force W, the piezoelectric film 10 portion of the elastic band 15 is as shown in FIG. The edge of the piezoelectric film 10 is deformed as if narrowly constricted. For this reason, a large strain concentrates on the edge of the piezoelectric film 10, and an unreasonable deformation occurs in the piezoelectric film 10. On the other hand, by providing an elastic member 20 having a Young's modulus smaller than the Young's modulus of the piezoelectric film 10 covering the piezoelectric film 10 as shown by a one-dot chain line in FIG. It is possible to prevent the film 10 from being excessively deformed.

  The effect of this elastic member 20 is shown in FIG. The graph of FIG. 6 represents the relationship between the tensile load W and the elongation δ of the large deformation sensor when an external force (tensile load) W is applied to the large deformation sensor 110. The horizontal axis of the graph of FIG. 6 is the elongation δ of the large deformation sensor 110, and the vertical axis is the tensile load W and the output voltage V of the piezoelectric film 10. According to FIG. 6, it can be seen that elongation up to about 140% can be measured with high accuracy. Comparing FIG. 3 and FIG. 6, it can be seen that the large deformation sensor 110 can measure the elongation more than twice that of the large deformation sensor 100, and that the effect of providing the elastic member 20 is great. It can also be seen that there is a good proportional relationship between the tensile load W and the output voltage V.

  In addition, FIG. 6 tested using the large deformation sensor of the following structures. The elastic band 15 is made of rubber with a width of 30 mm, a length of 260 mm, and a thickness of 2 mm. A piezoelectric film 10 made of PVDF with electrodes with aluminum deposited on the entire front and back surfaces is embedded in almost the center of the elastic band 15. Yes. The piezoelectric film 10 had a thickness of 0.04 mm, a width of 30 mm, and a length of 30 mm. An elastic member 20 made of black natural rubber having a thickness of 1 mm and a length of about 45 mm is bonded to the front and back surfaces of the elastic band 15 so as to cover the piezoelectric film 10.

The tensile load W was given by holding the large deformation sensor 110 vertically by grasping it with the upper chuck of the tensile tester and pulling the lower end portion of the large deformation sensor 110 downward to a predetermined length by hand. The tensile load W was read from the load cell of the tensile tester. The measurement of the output voltage of the large deformation sensor 110 was performed using an Omniace voltage recorder manufactured by NEC Sanei Co., Ltd. having a 0.47 μF capacitor connected in parallel and having an internal resistance R _{0 of} 1 MΩ.

  The embodiment of the present invention further includes a large deformation sensor having the following configuration. According to this large deformation sensor, it is possible to easily detect complicated human movements and behavioral states. That is, as shown in FIG. 7, the large deformation sensor 120 is provided with a pair of elastic bands 15 that are spaced apart from each other in the longitudinal direction of the elastic band 15 and output a signal corresponding to the strain in the longitudinal direction of the elastic band 15. The piezoelectric film 11 (11A, 11B).

  In this large deformation sensor 120, the piezoelectric film 10 is disposed at the end of the elastic band 15 in the large deformation sensors 100 and 110, and a piezoelectric film equivalent to the piezoelectric film 10 is disposed at the opposite end. It has the form. That is, the pair of piezoelectric films 11A and 11B of the large deformation sensor 120 have the same shape and are arranged to face each other. In the large deformation sensor 120, the elastic band 15 should have a Young's modulus of 0.5 to 10 Mpa as in the large deformation sensors 100 and 110. When the elastic member 20 has the elastic member 20, the Young's modulus of the elastic member 20 is It should be 0.5-10 Mpa.

  The large deformation sensor 120 is used as follows. That is, both ends are stretched and fixed so as to give the required initial elongation to the large deformation sensor 120, and the large deformation sensor 120 (elastic band 15) is located at a portion between the pair of piezoelectric films 11A and 11B, for example, point P. It is used so that an external force F is applied in the longitudinal direction.

  When the external force F is applied, the elastic band 15 on the left side of the position where the external force F is applied in FIG. 7 is extended by δ, and the elastic band 15 on the right side is reduced by δ. At this time, an output voltage corresponding to the deformation is obtained from the pair of piezoelectric films 11A and 11B arranged in the large deformation sensor 120. From this output voltage, the magnitude of the external force F, the deformation amount δ of the large deformation sensor 120 (elastic band 15), the position where the external force F is applied, and the like can be obtained.

  FIG. 8 shows temporal changes in output voltage obtained from the pair of piezoelectric films 11 when a longitudinal external force F is applied to each position in the longitudinal direction of the large deformation sensor 120. In the graph of FIG. 8, the horizontal axis represents time s, and the vertical axis represents the output voltage V of the piezoelectric film 11. In FIG. 8, the solid line (11A) indicates the output voltage of the left piezoelectric film 11A, and the broken line (11B) indicates the output voltage of the right piezoelectric film 11B. Further, “loading F to (1/3) L” shown in FIG. 8 means that the point P is 1/3 of the total length L of the large deformation sensor 120 from the left end of the large deformation sensor 120 as shown in FIG. It means that external force F is loaded. The external force F was applied by applying a lateral force by grasping the point P of the elastic band 15 by hand.

  According to FIG. 8, when the external force F is repeatedly loaded at the position of (1/2) L (center portion) of the large deformation sensor 120, the left and right portions of the elastic band 15 are alternately sandwiched across the load point P of the external force. The output voltages of the piezoelectric films 11A and 11B show waveforms with the same amplitude and reversed phase. (1/6) When the external force F is repeatedly applied to the position of L, the absolute value of the strain of the left elastic band 15 is larger than the absolute value of the strain of the right elastic band 15 from the position where the external force F is applied. Therefore, the amplitude of the output voltage of the left piezoelectric film 11A is larger. When an external force F is loaded at the position (1/3) L, an intermediate output voltage between (1/6) L and (1/2) L is measured. That is, it can be seen that the action point P of the external force can be determined by comparing the output voltage waveforms of the pair of piezoelectric films 11A and 11B.

  The various embodiments of the large deformation sensor according to the present invention have been described above. However, the large deformation sensor according to the present invention can have the following structure. For example, the elastic band 15 is not limited to a rectangular cross section, but may be an oval or a hollow circular tube. In this case, the piezoelectric film 10 sandwiched between the elastic bands 15 may be any film as long as the shape of the cross section thereof is symmetric with respect to the symmetry axis of the cross section of the elastic band 15 as described above.

  Further, as shown in FIG. 9, the portion provided with the elastic member 20 of the large deformation sensor 110 has the elastic member 20 in the elastic band 15 in a state where the piezoelectric film 10 with the electrode 13 is wrapped with the elastic member 20. It is also possible to have a structure in which is embedded. In this case, there is an advantage that the large deformation sensor 110 can be relatively easily manufactured. In the case of manufacturing a large deformation sensor by bonding the piezoelectric film 10, the elastic member 20, or the elastic band 15, respectively, a rubber-based adhesive having an elastic property of the cured adhesive substantially equal to that of the elastic band is used. It is good to use. On the other hand, the large deformation sensor 110 can be manufactured by pouring a liquid elastic band material between the elastic band 20 or the elastic member 20 and the piezoelectric film 10 and curing it.

  As described above, the elastic member 20 has an effect of preventing the elastic band 15 from being stretched and preventing the piezoelectric film 10 from being excessively deformed. Therefore, the elastic member 20 is not necessarily provided as long as such an effect can be exhibited. The shape of the elastic band 15 may be dealt with, for example, by making the elastic band 15 including the piezoelectric film 10 larger or thicker.

  In order to measure the elongation of the object to be measured or the magnitude of the external force applied to the object to be measured using the large deformation sensor 100, 110 or 120, the large deformation sensor 100, 110 or 120 has both ends thereof. Used attached to the object to be measured. There are various methods for attaching these sensors to the object to be measured, depending on the purpose of measurement. For example, a method of fastening both ends of the elastic band 15 with metal fittings or a method of fixing bolts by providing bolt holes at both ends is used. Further, when the large deformation sensor is used in a stretched state, for example, when measuring both expansion and contraction by the large deformation sensor 100, both ends of the elastic band 15 are previously stretched and attached to the support member. The large deformation sensor 100 is used by being fastened and fixed to an object to be measured, for example, with a metal fitting. Further, in these fixing methods, various methods such as rigid connection or pin connection are used for the connection between the large deformation sensor and the object to be measured or the support member.

  As described above, there are various methods for coupling the large deformation sensor and the object to be measured, and the elastic band portion of the large deformation sensor can be directly attached to the object to be measured or the support member, but at both ends of the elastic band. It is good to attach the supporting member used as an attaching part. An example of such a support member is shown in FIG. FIG. 10 shows the left end portion of the deformation sensor 100 or 110, and the support member 40 is formed by integrally impregnating three strip-like cloths sandwiching the elastic band 15 with rubber. In this case, the material of the rubber is not particularly limited. For example, rubber can be used. The material of the cloth is not particularly limited. For example, canvas can be used. By attaching such a support member to the large deformation sensor, the durability and accuracy of the large deformation sensor can be improved. Moreover, the large deformation sensor can be easily attached to the object to be measured.

  In addition, the present invention includes the following behavior detection apparatus to which the large deformation sensor is applied. For example, the behavior detection sensor 210 of the seat occupant 51 is a behavior detection sensor of the seat occupant 51 disposed on or in the seat body 45 as shown in FIG. 11, and has a Young's modulus of 0.5 to 10 MPa. The elastic band 15, a pair of piezoelectric films 11A and 11B that are arranged in the longitudinal direction of the elastic band 15 and output a signal corresponding to the strain in the longitudinal direction of the elastic band 15, and the elastic band 15 are stretched. And a support member 46. As the elastic band 15 and the pair of piezoelectric films 11A and 11B, those equivalent to those used in the large deformation sensor 120 can be used. As the support member 46, a part of the seat body 45 can be used. The support member 46 may be configured such that the elastic band 15 is stretched and fixed.

  As shown in FIG. 11, the behavior detection sensor 210 is used by being disposed in a state where an elastic band 15 is stretched on or inside a seat body 45, for example, a seat of a passenger car. For example, a seat occupant 51 sitting at the center of the seat body 45 moves up and down, moves right (to the right), moves up and down, rolls, and shares as shown in FIGS. 12 is obtained from the pair of piezoelectric films 11A and 11B.

  When the seat occupant 51 moves up and down in the center of the seat body 45 (FIG. 12 (a)), the left and right elastic bands 15 on which the seat occupant 51 sits extend and contract with approximately the same length. The waveforms of the left and right piezoelectric films 11A and 11B are almost the same. The greater the weight of the occupant 51 and the greater the fluctuation, the greater the fluctuation range of the output voltages of the piezoelectric films 11A and 11B. Next, when the seat body 45 is swung up and down near the right side (FIG. 12B), the right side portion of the elastic band 15 expands and contracts more than the left side portion, so that the left and right piezoelectric films 11A and 11B A difference occurs in the waveform, and the fluctuation range of the output voltage of the right piezoelectric film 11B is larger than the width of the output voltage of the left piezoelectric film 11A.

  Next, in the case of rolling (FIG. 12 (c)), the load position of the butt portion moves alternately to the right side and the left side of the elastic band 15, so the left side portion and the right side portion of the elastic band 15 are alternated. The output voltages of the piezoelectric films 11A and 11B show waveforms whose phases are reversed. In the case of sharing (FIG. 12D), when the body moves in the right direction, the left side portion of the elastic band 15 is pulled by the frictional force, and the right side portion is loosened. Conversely, when the body moves from right to left, the right side portion of the elastic band 15 is pulled and the left side portion is loosened. As a result, the output voltages of the left and right piezoelectric films 11A and 11B are reversed in phase.

  Thus, the output voltage from the pair of piezoelectric films varies depending on each movement of the seat occupant. That is, according to the behavior detection sensor 210, an output voltage corresponding to each motion of the seat occupant can be obtained, and therefore the behavior of the seat occupant can be detected by analyzing the time variation. FIG. 13 or 14 shows an example of a seat occupant state monitoring apparatus using the behavior detection sensor 210.

The state monitoring apparatus 250 of the seated person 51 in FIG. 13 includes a behavior detection sensor 210, a measurement unit 61 for the output signals V ₁ and V ₂ of the pair of piezoelectric films 11A and 11B of the behavior detection sensor 210, and a measurement unit 61. The measured V _l and V ₂ phase calculating means 62, the V _l and V ₂ adding and subtracting calculating means 63 and the subtracting calculating means 64, and the weight of the seat 51 and the center of gravity of the seat 51 from the calculation results of these calculating means It comprises determination means 65 for determining the position.

In the phase calculating means 62, V _l, the extraction of the peak value of V _2, or V _l, by comparison of V ₂ increases or decreases the gradient, V _l and V ₂ are computed whether a reverse phase or the same phase. If V _l and V ₂ are in the same phase, it is considered that the seat 51 is moving up and down, and the weight of the seat 51 is calculated by the addition calculation means 63 of V _l and V ₂ , and V _l seating position of the seat's 51 or a longitudinal central portion of the deformation sensor, calculates whether it is more or left is from right by the subtraction arithmetic means 64 of the V ₂ and. And from these calculation results, the judgment means 65 classifies and judges the weight and seating position of the occupant 51 step by step, thereby monitoring the occupant 51 state, determining that the person has been seated, and leaving the seat. Can be determined.

The state monitoring device 251 of the seated person 51 in FIG. 14 includes a behavior detection sensor 210, a measurement unit 61 for the output signals V ₁ and V ₂ of the pair of piezoelectric films 11A and 11B of the behavior detection sensor 210, and a measurement unit 61. The phase calculation means 62 of the measured V _l and V ₂ , the differential calculation means 66 of the subtraction values of V _l and V ₂ , and the determination means for determining the moving speed of the position of the seat 51 from the calculation results of these calculation means It consists of 65.

In the phase calculating means 62, V _l, the extraction of the peak value of V _2, or V _l, by comparison of V ₂ increases or decreases the gradient, V _l and V ₂ are computed whether a reverse phase or the same phase. When V _l and V ₂ are in opposite phases, it is considered that the position of the occupant 51 has moved in the horizontal direction, and the occupant is determined from the calculation result by the differential calculation means 66 of (V ₁ −V ₂ ). The determination means 65 determines the moving speed of 51. When the seat 51 moves the body position voluntarily, the movement speed is relatively slow due to the inertia of the body, but when the seat 51 slides sideways due to the external load Since the movement speed increases, the cause of movement can also be determined by classifying the movement speed in stages.

  Further, the behavior detection sensor 210 can be used for monitoring the behavior of a cared person when installed on a sitting chair or a sofa used by the cared person in the care field. In addition, when the behavior detection sensor 210 is stretched in the front-rear direction on or inside the automobile seat, it can be used to determine whether the seated person is seated in front of or behind the seat, It is also possible to determine the forward jump speed when a person collides.

  The present invention also includes the following game / training apparatus to which the large deformation sensor is applied. For example, FIG. 15 shows an example of a game / training apparatus. The game / training device 260 is provided with a pair of elastic bands 15 having Young's modulus of 0.5 to 10 MPa and a signal that is arranged in the longitudinal direction of the elastic band 15 and that corresponds to the strain in the longitudinal direction of the elastic band 15. Piezoelectric films 11A and 11B, a support member 48 for fixing both ends of the elastic band 15, signal processing means 67 for processing signals from the pair of piezoelectric films 11A and 11B, and signals processed by the signal processing means 67 Display means 68 for displaying, and a load acting portion 37 from a player or trainer 52 is provided in the elastic band 15 portion between the pair of piezoelectric films 11A and 11B. The player or trainer 52 is interested in knowing the direction or magnitude of the load applied by the display means 68 by adding an arbitrary load with the load acting unit 37, or knowing the comparison result with the reference value. A game or training can be performed.

The signal processing means 67 of the present invention includes a measuring means for measuring the signals V ₁ and V ₂ from the piezoelectric films 11A and 11B, and the magnitude of the force applied to the deformation sensor by the player from the measurement value measured by the measuring means and The calculation means for calculating the timing, the database storing the training program, and the comparison means for comparing the data stored in the database with the result of the calculation means can be used. Further, the display means can display the result of the calculation means and the result of the comparison means and can display the degree of training to the game or the trainee.

  In the measuring means, the output signal of the piezoelectric film is A / D converted and taken into a computer, and the magnitude and direction of the force applied by the player or trainee and its timing are calculated inside the computer. In addition, teaching data that teaches a series of actions of magnitude, direction, and timing of force is prepared in the computer as a plurality of types of training databases, and a trainer or a player chooses a desired database for training. Or you can play.

  The database selected for the training is displayed to the trainee or the player by the display means of sound, image or both through the computer. Then, the calculation result obtained by calculating the magnitude and direction of the force applied by the trainee and the timing thereof is compared with the database and displayed on the display means 68 such as voice or image for each operation. Moreover, you may make it display as a score at the end of a series of training.

  The training database may be configured as, for example, an interesting software incorporating a game or game element incorporating a body motion. Moreover, in addition to the force signal applied to the large deformation sensor from the player or trainee, the input means for inputting by the operation of the push button, and the signal processing means of the game / training apparatus by processing the signal from the input means It is preferable to provide interrupt means 69 for inputting to the input. The input means / interrupt means can be, for example, an ON-OFF switch. The contents of the game or training can be complicated by the input means / interrupt means, and the player or the trainee can be interested in playing the game or training.

  FIG. 16 shows a game / training apparatus in which the center portion of the elastic band is grasped with a hand and pulled strongly toward the front side, when pulled toward the front and right direction (45 degrees direction), and when pulled toward the right direction. An example of an output signal from the piezoelectric film is shown. In FIG. 16, the output of the left and right piezoelectric films is almost the same when pulled strongly toward the front side, but when pulled toward the front and the right direction (45 degree direction), the output voltage of the left piezoelectric film increases. Further, when pulled rightward, the output voltage of the right piezoelectric film is almost zero. By calculating the magnitude, direction and timing of the force applied to the elastic band from the peak value of the output signal and comparing it with the data in the database, the player or trainer can know the degree of the game or training. it can.

  In the example of the above game / training device, the load acting portion 37, which is a portion to which the player or the trainee 52 gives a load for playing or training, is provided in the elastic band 15 portion between the pair of piezoelectric films 11A and 11B. However, by providing these at both ends of the elastic band 15, it is possible to enjoy further different games and training.

It is the top view (a) and enlarged sectional view (b) of the large deformation sensor which concern on this invention. FIG. 2 is an electric circuit diagram of the large deformation sensor of FIG. 1. It is a graph which shows the relationship between the expansion | extension of the large deformation | transformation sensor of FIG. 1, and an output voltage. It is the top view (a) and enlarged sectional view (b) of the large deformation sensor of other one embodiment. It is a schematic diagram explaining the deformation | transformation characteristic of the large deformation sensor of FIG. It is a graph which shows the relationship between the elongation of the large deformation | transformation sensor of FIG. 4, and a tensile load. It is a top view of the large deformation sensor of other two embodiments. It is a graph which shows the time change of the output voltage of the large deformation | transformation sensor of FIG. It is the top view (a) and enlarged sectional view (b) of the large deformation sensor of the modification of embodiment of FIG. It is sectional drawing which shows the structure of the supporting member part of a large deformation sensor. It is a schematic diagram which shows a behavior detection sensor and its usage example. It is a graph which shows the time change of the output voltage of the behavior detection sensor of FIG. It is a schematic diagram which shows the structure of a seated person's state monitoring apparatus using the behavior sensor of FIG. It is a schematic diagram which shows the modification of the seated person's state monitoring apparatus of FIG. It is a schematic diagram which shows the structure of a game / training apparatus. It is a graph which shows the time change of the output voltage of the game and training apparatus of FIG.

Explanation of symbols

10 Piezoelectric film
11, 11A, 11B Piezoelectric film
13, 13A, 13B electrode
15 Elastic band
18, 18A, 18B wiring
20 Elastic member
37 Load action part
40 Support member
45 seat body
46, 48 Support member
51 Seats
52 Players or trainers
60 Voltage detector
61 Measuring means
62 Phase calculation means
63 Addition calculation means
64 Subtraction operation means
65 Judgment means
66 Differential operation means
67 Signal processing means
68 Display means
69 Interruption means
100 Large deformation sensor
110 Large deformation sensor
120 Large deformation sensor
210 Behavior detection sensor
250 seat occupant condition monitoring device
251 Seat condition monitoring device
260 Games and training equipment

Claims (15)

  A large deformation sensor comprising an elastic band and a piezoelectric film that outputs a signal corresponding to the strain in the longitudinal direction of the elastic band. The large deformation sensor according to claim 1, wherein the elastic band and the elongation stiffness E × A of the piezoelectric film satisfy the following expression (1).
(E ₁ × A ₁ ) / (E ₂ × A ₂ ) = 3 to 300 (1)
Here, E ₁ and E ₂ are Young's moduli of the piezoelectric film and the elastic band, respectively, and A ₁ and A ₂ are the cross-sectional area of the piezoelectric film in the cross section including the piezoelectric film and the crossing of the elastic band, respectively. It is an area. An elastic band, a piezoelectric film that outputs a signal corresponding to the strain in the longitudinal direction of the elastic band, and an elastic member that covers the piezoelectric film and deforms integrally with the elastic band, Large deformation sensor to satisfy.
E ₂ ≦ E ₃ <E _l (2)
Here, E ₁ is the Young's modulus of the piezoelectric film, E ₂ is the Young's modulus of the elastic band, and E ₃ is the Young's modulus of the elastic member. The large deformation sensor according to claim 3, wherein the elastic band, the piezoelectric film, and the elastic member have an elongation rigidity E × A that satisfies the following expression (3).
_{(E 1 × A 1 + E} 3 × A 3) / (E 2 × A 2) = 3~300 (3)
Here, E ₁ , E ₂ , and E ₃ are Young's moduli of the piezoelectric film, elastic band, and elastic member, respectively, and A ₁ , A ₂ , and A ₃ are transverse sections including the piezoelectric film and elastic member of the elastic band. The cross-sectional area of each surface of the piezoelectric film, the cross-sectional area of the elastic band, and the cross-sectional area of the elastic member.   A large deformation sensor comprising: an elastic band; and a pair of piezoelectric films that are spaced apart in the longitudinal direction of the elastic band and output a signal corresponding to the strain in the longitudinal direction of the elastic band. An elastic band, a pair of piezoelectric films that are spaced apart in the longitudinal direction of the elastic band and output a signal corresponding to the strain in the longitudinal direction of the elastic band; and the elastic band that covers the pair of piezoelectric films and the elastic band A large deformation sensor that consists of an elastic member that deforms integrally and satisfies the following formula (4).
E ₂ ≦ E ₃ <E _l (4)
Here, E ₂ is the Young's modulus of the elastic band, E ₁ is the Young's modulus of the piezoelectric film, and E ₃ is the Young's modulus of the elastic member.   The large deformation sensor according to any one of claims 1 to 6, wherein the elastic band has a Young's modulus of 0.5 to 10 MPa.   The large deformation sensor according to any one of claims 3, 4, 6 and 7, wherein the elastic member has a Young's modulus of 0.5 to 10 MPa.   A behavior detection sensor for a seat occupant disposed on or in a seat body, the elastic band having a Young's modulus of 0.5 to 10 MPa, and the elastic band spaced apart in the longitudinal direction of the elastic band. A sensor for detecting a occupant's behavior, comprising: a pair of piezoelectric films that output a signal corresponding to a strain in a longitudinal direction; and a support member that stretches the elastic band. A behavior detection sensor according to claim 9, a measuring means for output signals V _l and V ₂ of a pair of piezoelectric films of the behavior detection sensor, a phase calculation means for V _l and V ₂ measured by the measuring means, , V _l , V ₂ addition and subtraction calculation means, and a seat occupant state monitoring device comprising determination means for determining the weight of the seat occupant and the center of gravity position of the seat occupant from the calculation results of the calculation means. A behavior detection sensor according to claim 9, a measuring means for output signals V _l and V ₂ of a pair of piezoelectric films of the behavior detection sensor, a phase calculation means for V _l and V ₂ measured by the measuring means, , V _l , V ₂ subtraction value differential calculation means, and a seat occupant state monitoring device comprising a determination means for determining the movement speed of the position of the seat occupant from the calculation results of the calculation means.   An elastic band having a Young's modulus of 0.5 to 10 MPa, a pair of piezoelectric films that are spaced apart in the longitudinal direction of the elastic band and output a signal corresponding to the strain in the longitudinal direction of the elastic band; A support member that fixes both ends; a signal processing unit that processes a signal from the pair of piezoelectric films; and a display unit that displays a signal processed by the signal processing unit. A game / training apparatus in which a load acting portion from a player or a trainee is provided at the elastic band portion or both ends of the elastic band.   The signal processing means includes a measurement means for measuring a signal from the piezoelectric film, a calculation means for calculating the magnitude and timing of the force applied to the deformation sensor by the player from the measurement value measured by the measurement means, and a training program The game / training apparatus according to claim 12, further comprising: a database that stores data, and a comparison unit that compares the data stored in the database with a result of the calculation unit.   14. The game / training apparatus according to claim 12 or 13, wherein the display means is capable of displaying a result of the computing means and a result of the comparing means and displaying a training level to a trainee.   15. An input means for inputting a signal from a player or a trainee to the game / training apparatus according to claim 12, and a signal processing of the game / training apparatus by processing a signal from the input means. A game / training apparatus comprising an interruption means for inputting to the means.

Images