JP2016123433A - Sensor for measuring walking and footwear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensor for measuring walking, a sensor that can detect more delicate motion than conventionally.SOLUTION: With the sensor for measuring walking, time change of a load can be acquired. For example, when the heel touches the ground, a sensor part 11D arranged in the heel section projectingly curves in the -Z direction from a flat state, so that the output of the sensor part 11D indicates a negative peak value. When the toe touches the ground, a sensor part 11A arranged in the toe section projectingly curves in the -Z direction from the flat state, so that the output of the sensor part 11A indicates a negative peak value. When the heel rises, the sensor part 11D arranged in the heel section changes from the state projectingly curved in the -Z direction to the flat state. Consequently, the output of the sensor part 11D indicates a positive peak value. When the toe is kicked out, the sensor part 11A arranged in the toe section changes from state projectingly curved in the -Z direction to the flat state. Consequently, the output of the sensor part 11A indicates a positive peak value.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a walking measurement sensor that is mounted on footwear such as shoes and measures the state of walking, and footwear provided with the walking measurement sensor.

  2. Description of the Related Art Conventionally, it has been proposed to attach a piezoelectric sheet to a shoe and detect the deformation of the bottom of the shoe that occurs during exercise.

  For example, the displacement sensor of Patent Document 1 is provided at the heel portion, the base portion of the thumb, the base portion of the little finger, and the arch portion, and detects the deformation of the shoe sole when the wearer moves.

JP2013-233269A

  The displacement sensor of patent document 1 detects the displacement amount (elongation) of the surface direction of the bottom part of shoes. That is, as shown in FIG. 4, the displacement sensor of Patent Document 1 has the bottom of the shoe in the surface direction, for example, when the foot touches the ground and when the foot protrudes from the ground. It detects the expansion and contraction timing.

  By merely detecting such a displacement amount in the surface direction, a more detailed operation (for example, protruding toe, landing on toe, landing on heel, or levitation on heel, etc.) beyond that disclosed in Patent Document 1 is detected. Is difficult.

  In view of the above, an object of the present invention is to provide a walking measurement sensor capable of detecting a more precise motion than in the past.

  The present invention is a walking measurement sensor, comprising a displacement detection film that is attached to a portion that is deformed by being pressed by a sole, and the displacement detection film is an output corresponding to a time change of a load due to the pressing. It is characterized by having.

  The load on footwear such as shoes increases with time when landing, and decreases with time when ascending. Therefore, the time change of the load is different in polarity between landing and rising. Therefore, the sensor for walking measurement according to the present invention can detect a more precise operation than before by acquiring the time change of the load. For example, it is possible to detect precise movements such as toe protrusion, toe landing, heel landing, or heel ascent.

  In addition, in order to detect the time change of a load, it is preferable that a displacement detection film is provided with a pair of piezoelectric film, and the direction of the electric charge which generate | occur | produces at the time of expansion / contraction is reverse. By reversing the direction of the electric charge generated during expansion / contraction, it does not react to expansion / contraction of the shoe sole, and only the bending of the shoe sole (displacement in the normal direction of the shoe sole) can be detected. The bending of the shoe sole increases with time when landing and decreases with time when ascending. Accordingly, the walking measurement sensor can appropriately detect a change in load over time.

  The piezoelectric film preferably contains polylactic acid. Polylactic acid has no pyroelectricity and is suitable for installation on shoes that come into contact with the human body. In addition, polylactic acid generates charges according to changes in strain. Accordingly, the charge direction is reversed between landing and rising, which is suitable for detecting a change in load over time.

  In addition, the signal processing part which processes the output signal of a displacement detection film may be incorporated in the sensor for walk measurement, and may be connected via a signal line as another component.

  The signal processing unit preferably adds time information to the output signal of the displacement detection film. For example, when a displacement detection film for the right foot and a displacement detection film for the left foot are provided, the detection result of the right foot and the detection result of the left foot can be synchronized by using time information.

  The walking measurement sensor as described above may be integrated with a shoe, or may be sandwiched between an insole and a shoe sole, for example. Alternatively, it may be an insole with a built-in sensor for walking measurement.

  According to the present invention, it is possible to detect a more precise operation than in the past.

FIG. 1A is a side view of a shoe 100 provided with the walking measurement sensor of the present invention, and FIG. 1B is a view of the shoe 100 as seen from the back side. It is a side view of sensor part 11A. 1 is a top view of a film 1. FIG. It is a side view of sensor part 11A when an insole is extended in the width direction. It is a side view of a sensor element when a load is applied to the insole. It is a side view which shows the example which abbreviate | omitted the film 1 and the film 4. FIG. 7A is a block diagram illustrating a configuration for processing an output signal of each sensor unit, and FIG. 7B is a circuit diagram. It is a figure which shows the example of a circuit using an operational amplifier. It is a figure which shows the time change of the output signal of each sensor part. FIG. 10A is a view of the shoe 100 as seen from the back surface when the walking measurement sensor is provided on the shoes of both feet, and FIG. 10B is a block diagram. It is a figure which shows the time change of the output signal of each sensor part in the case of providing the sensor for walk measurement in shoes of both feet.

  FIG. 1A is a side view of a shoe 100 provided with the walking measurement sensor of the present invention, and FIG. 1B is a view of the shoe 100 as seen from the back side.

  The walking measurement sensor includes a sensor unit 11A, a sensor unit 11B, a sensor unit 11C, and a sensor unit 11D. The sensor unit 11A, the sensor unit 11B, the sensor unit 11C, and the sensor unit 11D are disposed between the shoe sole 31 and the insole 51, respectively. In addition, each sensor part should just be mounted | worn in the location which deform | transforms by pressing with a sole, for example, may be incorporated in the shoe sole 31. FIG. However, replacement of the sensor unit is facilitated by being disposed between the shoe sole 31 and the insole 51.

  The sensor unit 11A, the sensor unit 11B, the sensor unit 11C, and the sensor unit 11D are connected to a signal processing unit 25 built in the shoe sole 31. However, the signal processing unit 25 does not need to be built in the shoe sole 31, and may be installed between the shoe sole 31 and the insole 51, for example.

  The sensor unit 11A is arranged at the toe part, the sensor part 11B is arranged at the base part of the thumb, the sensor part 11C is arranged at the base part of the little finger, and the sensor part 11D is arranged at the heel part.

  FIG. 2 is a cross-sectional view of the sensor unit 11A. The sensor unit 11A, the sensor unit 11B, the sensor unit 11C, and the sensor unit 11D all have the same configuration. Therefore, in FIG. 2, the sensor unit 11A is shown as a representative.

  The sensor unit 11A includes a film 1, a film 2, a film 3, a film 4, a reference potential electrode 5, a signal electrode 6, a reference potential electrode 7, and a connection unit 8. The film 2 is disposed on the upper surface (Z-direction surface) of the signal electrode 6, and the film 3 is disposed on the lower surface (−Z-direction surface). The film 1 is disposed on the upper surface of the film 2, and the film 4 is disposed on the lower surface of the film 3. A reference potential electrode 5 is disposed on the upper surface of the film 1, and a reference potential electrode 7 is disposed on the lower surface of the film 4.

  In the sensor unit 11 </ b> A, the reference potential electrode 5 side contacts the insole 51, and the reference potential electrode 7 side contacts the shoe sole 31. However, conversely, the reference potential electrode 7 side may contact the insole 51, and the reference potential electrode 5 side may contact the shoe sole 31. The sensor unit 11A is actually covered with a protective material such as resin, but is omitted in this embodiment.

  The reference potential electrode 5 and the reference potential electrode 7 are connected via a connecting portion 8 and are electrically connected. The reference potential electrode 5, the reference potential electrode 7, and the connecting portion 8 are integrally formed by bending, for example, a urethane film coated with a silver paste. A signal line 21 is connected to the end portion of the reference potential electrode 7 in the −Y direction, and is connected to the signal processing unit 25.

  The signal electrode 6 is made of, for example, copper (Cu). A signal line 22 is connected to the end of the signal electrode 6 in the −Y direction, and is connected to the signal processing unit 25.

  Since the silver paste used for the reference potential electrode 5 and the reference potential electrode 7 has a Young's modulus smaller than that of the copper foil used for the signal electrode 6, a strain larger than that of the copper foil is caused by the same stress. By arranging the reference potential electrode 5 and the reference potential electrode 7 which are easily distorted in the outermost layer and the signal electrode 6 made of a copper foil which is not easily distorted in the center, the sensor unit 11A is arranged in the thickness direction (Z direction and − The load with respect to the (Z direction) is easily deformed, and is less likely to expand and contract in the surface direction. Further, copper is less likely to be ionized and migration is less likely to occur than silver.

  Film 1, film 2, film 3, and film 4 each contain polylactic acid, which is a piezoelectric resin. Film 1, film 2, film 3 and film 4 have the same thickness.

  Film 1, film 2, film 3, and film 4 each generate an electric charge when distortion in a predetermined direction occurs on the main surface. The charge direction of each film depends on the direction of strain (elongation or contraction), the orientation direction of polylactic acid molecules, and the composition of polylactic acid. For example, the direction of strain is the same, the orientation direction of the molecules of polylactic acid is the same, and the composition of polylactic acid is D-type polylactic acid (PDLA (; Poly-D-Lictic Acid)) and L-type polylactic acid ( In the case of two films different from PLLA (; Poly-L-Lictic Acid)), the charge directions of the respective films are opposite to each other. In the present embodiment, the charge direction indicates a direction from one main surface where negative charges are generated to the other main surface where positive charges are generated.

  Film 1, film 2, film 3, and film 4 are each stretched in the direction of 45 ° counterclockwise from the −Y direction as viewed in a plan view of sensor portion 11 </ b> A as indicated by arrow 911 in FIG. 3. (The film 1 is representatively shown in FIG. 3). Therefore, in the film 1, the film 2, the film 3, and the film 4, the polylactic acid molecules are oriented in a 45 ° direction counterclockwise from the −Y direction when the sensor unit 11A is viewed in plan.

  Film 1, film 2, film 3, and film 4 have the same orientation direction of polylactic acid molecules, but have different polylactic acid compositions. Film 1 and film 4 are each made of PDLA, and film 2 and film 3 are each made of PLLA. PLLA and PDLA are in an enantiomeric relationship. Therefore, when the orientation directions of the molecules are the same, when the strain (stretching or shrinking) in the same direction occurs between the PLLA film and the PDLA film, the directions of the generated charges are opposite to each other.

  As shown in FIG. 4, for example, when the insole 51 on the film 1 side extends in the width direction (Y direction and −Y direction), the film 1, the film 2, the film 3, and the film 4 extend in the width direction, respectively. Distortion occurs.

  Since the film 1 and the film 2 are integrated, they have substantially the same stretch amount. Moreover, since the film 3 and the film 4 are united, it becomes the respectively same expansion | extension amount. However, since the film 3 and the film 4 are connected to the film 2 via the signal electrode 6, the extension amount is smaller than that of the film 1 and the film 2.

  Since the film 1 is made of PDLA, the charge direction becomes the upward direction when a strain extending in the width direction occurs. Since the film 2 is made of PLLA, when a strain that expands in the width direction occurs, the charge direction becomes downward. Since the film 1 and the film 2 are equal in thickness and have substantially the same amount of extension, substantially the same amount of charge is generated. Therefore, the charge amount generated in the film 1 and the charge amount generated in the film 2 are offset.

  Similarly, since the film 3 is made of PLLA, when a strain extending in the width direction is generated, the charge direction is downward. Since the film 4 is made of PDLA, the charge direction becomes the upward direction when a strain extending in the width direction occurs. Accordingly, the amount of charge generated in the film 3 and the amount of charge generated in the film 4 are offset.

  On the other hand, when a load is applied to the insole 51 and a load in the normal direction is applied to the main surface of the sensor unit 11A, the film 1 and the film 2 are curved in a protruding manner in the −Z direction as shown in FIG. . Therefore, when the film 1 is based on the bonding surface of the film 1 and the film 2, the film 1 is distorted with respect to the film 2. Conversely, the film 2 is distorted to stretch with respect to the film 1 when the bonding surface of the film 1 and the film 2 is used as a reference. Therefore, the charge direction of the film 1 is downward, and the charge direction of the film 2 is downward. For this reason, the charge generated in the film 1 and the charge generated in the film 2 are added.

  Similarly, the film 3 is distorted with respect to the film 4 when the bonding surface of the film 3 and the film 4 is used as a reference. Further, the film 4 is distorted to stretch with respect to the film 3 when the film 3 and the bonding surface of the film 4 are used as a reference. Therefore, the charge direction of the film 3 is upward, and the charge direction of the film 4 is also upward. For this reason, the charge generated in the film 3 and the charge generated in the film 4 are added.

  The charge added by the films 1 and 2 raises the potential of the signal electrode 6 with respect to the reference potential electrode 5. The charge added by the films 3 and 4 raises the potential of the signal electrode 6 with respect to the reference potential electrode 7. Therefore, a large potential can be obtained at the signal electrode 6.

  In this way, the sensor unit 11 does not output during expansion and contraction in the surface direction of the insole 51, but can detect only the bending of the shoe sole (deformation due to a load in the Z direction or the −Z direction). The change of the load with respect to can be detected appropriately.

  In the above example, PDLA is used for the film 1 and the film 4 and PLLA is used for the film 2 and the film 3. However, for example, the film 1 is made using PLLA (or PDLA) for all the films. Also, the same function can be realized by arranging the film 2 and the film 2 in the stretching direction so as to be orthogonal to each other and making the stretching direction of the film 3 and the film 4 orthogonal.

  More simply, even if the film 1 and the film 4 are omitted, the same function can be realized. In this case, as shown in FIG. 6A, when the insole 51 expands and contracts in the surface direction, the charge amount generated in the film 2 and the charge amount generated in the film 3 can be offset, and the expansion and contraction in the surface direction Can be canceled. In addition, as shown in FIG. 6B, when a load in the −Z direction is applied to the insole 51, the charge amount generated in the film 2 and the charge amount generated in the film 3 can be added. it can.

  That is, the sensor unit may have any configuration as long as it includes a pair of piezoelectric films, and the pair of piezoelectric films has opposite directions of charge generated during expansion and contraction.

  The material of the film is not limited to polylactic acid, and other piezoelectric films such as polyvinylidene fluoride (PVDF) can also be used. In the case of PVDF, the charge direction can be set according to the direction of the electric field applied in the poling (polarization process).

  However, polylactic acid does not have pyroelectricity and is suitable for installation in places where body temperature is transmitted, such as shoes. In addition, polylactic acid generates charges according to changes in strain. Therefore, the charge direction is reversed between when the foot lands and the insole 51 is pushed in, and when the foot is raised and the insole 51 is released from the push. As a sensor for walking measurement, the landing timing and the rising timing can be individually detected by acquiring the change in the load (change on the time axis). Thereby, for example, it is possible to detect a precise operation such as protrusion of a toe, landing of a toe, landing on a heel, or levitation of a heel.

  FIG. 7A is a block diagram illustrating a configuration for processing an output signal of each sensor unit, and FIG. 7B is a circuit diagram. In this example, the J-FET 103 is built in the sensor unit 11A. In this example, when a voltage is generated in the piezoelectric element 101 composed of each film, an electric charge that cancels this voltage flows in by the resistor 102. A voltage corresponding to the current value generated at this time is applied to the gate of the J-FET 103 and detected by the A / D unit (A / D in the figure) in the signal processing unit 25. Thereby, the signal processing unit 25 detects a change in the load related to the sensor unit 11A.

  As described above, by disposing the J-FET 103 close to the piezoelectric element 101, the influence of noise can be reduced and the signal can be stabilized. An amplifier circuit may be provided between the sensor unit 11A and the signal processing unit 25. The signal processing unit 25 may be built in each sensor unit.

  Further, as shown in FIG. 8, an operational amplifier may be used to change the output of the operational amplifier according to the bending of the sensor unit 11. Since the operational amplifier variation is smaller than the FET variation, the sensitivity variation can be suppressed.

  Next, FIG. 9 is a diagram illustrating a time change of the output signal of each sensor unit. The horizontal axis of the graph shown in FIG. 9 is time, and the vertical axis is the detection value (value after A / D conversion) of the sensor.

  When the heel has landed, the heel portion of the insole 51 is pushed in and a load is applied. That is, the insole 51 of the heel portion shifts from a no load state to a maximum load state (a state in which the body weight is carried). At this time, the sensor unit 11D disposed in the heel portion curves in a protruding shape in the −Z direction from a flat state. Therefore, as in the graph shown in FIG. 9, the output of the sensor unit 11D indicates a negative peak value.

  When the toes land, the toe portion of the insole 51 is pushed in and a load is applied. That is, the insole 51 of the toe portion shifts from a no-load state to a maximum load state (a state in which the body weight rides). At this time, the sensor unit 11A disposed on the toe portion curves in a protruding shape in the −Z direction from a flat state. Therefore, as in the graph shown in FIG. 9, the output of the sensor unit 11A shows a negative peak value.

  On the other hand, when the heel rises, the heel portion of the insole 51 is released from the pushed-in state, and the load is reduced. That is, the insole 51 of the heel portion shifts from a maximum load state (a state where the weight is on) to no load. At this time, the sensor unit 11D arranged in the heel portion changes from a state in which it protrudes in the −Z direction to a flat state. Therefore, as in the graph shown in FIG. 9, the output of the sensor unit 11D indicates a positive peak value.

  When the toes are kicked out (when the toes are lifted), the toes of the insole 51 are released from being pushed in, and the load is reduced. In other words, the insole 51 of the toe portion shifts from a maximum load state (a state in which the body weight rides) to no load. At this time, the sensor unit 11A arranged on the toe portion changes from a state of being protruded in the −Z direction to a flat state. Therefore, as in the graph shown in FIG. 9, the output of the sensor unit 11A indicates a positive peak value.

  As illustrated in FIG. 7A, the signal processing unit 25 may output the output values of each sensor unit as described above to the user terminal 30. The user terminal 30 is an information processing terminal (for example, a smartphone, a personal computer, etc.) owned by the user. For example, the user terminal 30 performs a process of displaying a graph as shown in FIG. 9 on a display (not shown). Thereby, the user can know the timing of the start of the toe, the landing of the toe, the landing of the heel, or the rising of the heel.

  As shown in FIG. 9, when the heel is landed, it is the timing when the foot first comes into contact with the ground or the like from the state where the foot is completely lifted, so that the change in the load is large and the output value of the sensor unit 11D Is big. On the other hand, when the toes land, since the heel has already landed, the load change is small (the output value is relatively small).

  Similarly, when kicking out the toe, it is the timing when the foot shifts to a completely lifted state, so that the load change is large and the output value of the sensor unit 11A is large. On the other hand, when the heel is urgent, the toe is still landing, so the load change is small (the output value is relatively small). However, for example, when landing from the tiptoe first, the negative peak value of the sensor unit 11A increases, and conversely, the negative peak value of the sensor unit 11D decreases.

  For example, when a negative peak occurs in the sensor unit 11B arranged on the thumb side at a timing close to the timing at which the toes landed, it is determined that a load is applied to the thumb side when the toes land. Can do. On the other hand, when a negative peak occurs in the sensor unit 11C arranged on the little finger side at a timing close to the timing at which the toe landed, it is determined that a load is applied to the little finger side when the toe landed. Can do.

  In this way, the walking measurement sensor can detect a more precise operation than before.

  Further, as shown in FIG. 10, the walking measurement sensor can be provided on both feet. FIG. 10 (A) is a view of the shoe 100 as seen from the back surface when the walking measurement sensor is provided on the shoe of both feet. FIG. 10B is a block diagram of the sensor unit and the signal processing unit.

  In the shoe 100A for the right foot, a sensor unit 101A is installed on the toe part, and a sensor unit 101B is installed on the heel part. In the shoe 100B for the left foot, a sensor unit 101C is installed at the toe portion, and a sensor unit 101D is installed at the heel portion.

  The sensor unit 101A, the sensor unit 101B, the sensor unit 101C, and the sensor unit 101D all have the same configuration, and have the same configuration as the sensor unit 11A illustrated in FIG.

  The sensor unit 101A and the sensor unit 101B are connected to a first signal processing unit 25A built in the shoe for the left foot. The sensor unit 101C and the sensor unit 101D are connected to a second signal processing unit 25B built in the shoe for the right foot. The first signal processing unit 25A and the second signal processing unit 25B have the same configuration as the signal processing unit 25.

  However, in this case, the first signal processing unit 25A and the second signal processing unit 25B include an internal clock. The first signal processing unit 25 </ b> A and the second signal processing unit 25 </ b> B add time information to the output signal of each sensor unit, and output it to the user terminal 30. The internal clocks of the first signal processing unit 25A and the second signal processing unit 25B are synchronized at a predetermined timing (for example, by being connected at a terminal provided in each signal processing unit at the start of measurement). Thereby, the output signal of each sensor part can be synchronized.

  FIG. 11 is a diagram showing temporal changes in the output signals of the sensor units when a walking measurement sensor is provided on the shoes of both feet. As shown in FIG. 11, a more precise motion can be detected by providing a walking measurement sensor on the shoes of both feet. For example, in the example of FIG. 11, it can be seen that the landing of the right foot is stronger than the landing of the left foot. Therefore, for example, the left and right balance can be displayed on the user terminal 30. Further, by measuring the timing of landing and kicking, the walking speed, the stride of each foot, and the like can be measured and displayed on the user terminal 30.

  In this embodiment, an example in which the walking measurement sensor is installed on the shoe is shown. However, the walking measurement sensor of the present invention can be installed on footwear such as sandals, slippers, or clogs. It is. Further, footwear integrated with a walking measurement sensor also belongs to the technical scope of the present invention.

1, 2, 3, 4 ... Films 5, 7 ... Reference potential electrode 6 ... Signal electrode 8 ... Connection portions 11A, 11B, 11C, 11D ... Sensor portions 21, 22 ... Signal lines 25, 25A, 25B ... Signal processing portion 30 ... User terminal 31 ... Sole 51 ... Insole 100, 100A, 100B ... Shoes

Claims (7)

It is equipped with a displacement detection film that is attached to a place that is deformed by being pressed by the sole of the foot,
The sensor for walking measurement, wherein the displacement detection film has an output corresponding to a time change of a load caused by the pressing.   The sensor for walking measurement according to claim 1, wherein the displacement detection film includes a pair of piezoelectric films, and the pair of piezoelectric films has reverse directions of electric charges generated during expansion and contraction.   The walking measurement sensor according to claim 2, wherein the piezoelectric film contains polylactic acid.   The sensor for walking measurement according to any one of claims 1 to 3, further comprising a signal processing unit that processes an output signal of the displacement detection film.   The walking signal sensor according to claim 4, wherein the signal processing unit adds time information to an output signal of the displacement detection film. The signal processing unit includes a first signal processing unit for the left foot and a second signal processing unit for the right foot,
The walking measurement sensor according to claim 4 or 5, wherein each of the first signal processing unit and the second signal processing unit includes an internal clock and a terminal for synchronizing the internal clock.   Footwear comprising the sensor for walking measurement according to any one of claims 1 to 6.

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