JP6547293B2 - Sensor for measuring walking and footwear - Google Patents

Description

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

  Conventionally, it has been proposed to attach a piezoelectric sheet to a shoe and to 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, at the base portion of the thumb, at the base portion of the little finger, and at the arch portion, and detects deformation of the sole when the wearer exercises.

JP, 2013-233269, A

  The displacement sensor of Patent Document 1 detects an amount of displacement (elongation) in a surface direction of a bottom portion of a shoe. That is, in the displacement sensor of Patent Document 1, as shown in FIG. 4, the bottom of the shoe is in the surface direction, for example, that the foot is in contact with the ground and that the foot has come off the ground. It detects the timing of expansion and contraction.

  Only by detecting such an amount of displacement in the surface direction, it is possible to detect a more precise movement (for example, toe lifting, toe landing, heel landing, heel floating, etc.) as disclosed in Patent Document 1 It is difficult.

  Therefore, an object of the present invention is to provide a sensor for gait measurement capable of detecting a motion finer than in the past.

  The present invention is a sensor for measuring walking, which comprises a displacement detection film attached to a portion that is deformed by being pressed by a foot sole, and the displacement detection film has an output according to a time change of load due to the pressure. It is characterized by having.

  The load applied to footwear such as shoes increases with time when landing, and decreases with time when floating. Therefore, the time change of load differs in polarity at the time of landing and at the time of ascent. Therefore, the sensor for measuring walking according to the present invention can detect an operation more precise than in the past by acquiring the time change of the load. For example, precise motions such as toe lifting, toe landing, heel landing, or heel floating can be detected.

  In addition, in order to detect the time change of 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 and contraction is reverse. By reversing the direction of the charge generated during expansion and contraction, it is possible to detect only bending of the sole (displacement in the normal direction of the sole) without reacting to expansion and contraction of the sole. The bending of the sole increases with time at the time of landing, and decreases with time at the time of ascent. Therefore, the sensor for gait measurement can appropriately detect the time change of the load.

  The piezoelectric film preferably contains polylactic acid. Polylactic acid, which is not pyroelectric, is suitable for installation on shoes or the like that come in contact with the human body. In addition, polylactic acid generates a charge according to a change in strain. Therefore, the charge direction is reversed between the time of landing and the time of floating, which is suitable for detecting the time change of the load.

  Note that the signal processing unit that processes the output signal of the displacement detection film may be built in the sensor for measuring walking, or may be connected as a separate component via a signal line.

  Preferably, the signal processing unit adds time information to the output signal of the displacement detection film. For example, when the right foot displacement detection film and the left foot displacement detection film are provided, by using the time information, it is possible to synchronize the detection result of the right foot and the detection result of the left foot.

  The above-described sensor for measuring walking may be integrated with the shoe, or may be sandwiched, for example, under the insole and the sole of the shoe. Alternatively, an insole may be incorporated with a sensor for measuring walking.

  According to the present invention, it is possible to detect an operation that is more precise than conventional.

FIG. 1 (A) is a side view of a shoe 100 provided with the sensor for measuring walking according to the present invention, and FIG. 1 (B) is a view of the shoe 100 as viewed from the back. It is a side view of sensor part 11A. FIG. 2 is a top view of a film 1; It is a side view of sensor part 11A when insole spreads in the cross direction It is a side view of a sensor element when load is applied to an insole. It is a side view which shows the example which abbreviate | omitted the film 1 and the film 4. FIG. FIG. 7A is a block diagram showing 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 which used the 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 viewed from the back side when the sensors for measuring walking are 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 of a walk measurement in shoes of both feet.

  FIG. 1 (A) is a side view of a shoe 100 provided with the sensor for measuring walking according to the present invention, and FIG. 1 (B) is a view of the shoe 100 as viewed from the back.

  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 with the location which deform | transforms by being pressed by a foot sole, and may be incorporated in the shoe sole 31, for example. However, the sensor unit is arranged between the sole 31 and the insole 51 to facilitate replacement.

  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 need not be built in the shoe sole 31, and may be installed, for example, between the shoe sole 31 and the insole 51.

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

  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 representatively shown.

  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 connecting portion 8. The film 2 is disposed on the upper surface (the surface in the Z direction) of the signal electrode 6, and the film 3 is disposed on the lower surface (the surface in the -Z direction). 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 11A, the reference potential electrode 5 side contacts the insole 51, and the reference potential electrode 7 side contacts the sole 31. However, the reference potential electrode 7 may be in contact with the insole 51 and the reference potential electrode 5 may be in contact with the sole 31. In addition, although sensor part 11A is actually covered by protective materials, such as resin, it omits in this embodiment.

  The reference potential electrode 5 and the reference potential electrode 7 are connected via the connection portion 8 and electrically connected. The reference potential electrode 5, the reference potential electrode 7, and the connecting portion 8 are integrally formed, for example, by bending a urethane film coated with silver paste. The signal line 21 is connected to the end 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 an end of the signal electrode 6 in the −Y direction, and is connected to the signal processing unit 25.

  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, so that the same stress causes distortion larger than that of the copper foil. By arranging the reference potential electrode 5 and the reference potential electrode 7 which are easily distorted as described above in the outermost layer and the signal electrode 6 made of a copper foil which is hard to distort at the center, the sensor portion 11A can The load in the Z direction is more likely to be deformed and is less likely to expand and contract in the surface direction. In addition, copper is less likely to be ionized than silver and migration is less likely to occur.

  Each of the film 1, the film 2, the film 3 and the film 4 contains polylactic acid which is a piezoelectric resin. The film 1, the film 2, the film 3 and the film 4 each have the same thickness.

  The film 1, the film 2, the film 3 and the film 4 generate an electric charge when distortion in a predetermined direction on the main surface respectively occurs. The charge direction of each film depends on the direction of strain (extension or contraction), the orientation direction of the polylactic acid molecules, and the composition of the polylactic acid. For example, the strain direction is the same, the orientation direction of the polylactic acid molecules is the same, and the composition of the polylactic acid is D-type polylactic acid (PDLA (; Poly-D-Latic Acid)) and L-type polylactic acid (PDA). In the case of two films different from PLLA (; Poly-L-Latic 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 charge is generated to the other main surface where positive charge is generated.

  The film 1, the film 2, the film 3 and the film 4 are each stretched in the direction of 45 ° in the counterclockwise direction from the -Y direction, as shown by the arrow 911 in FIG. (The film 1 is shown representatively in FIG. 3). Therefore, the film 1, the film 2, the film 3 and the film 4 have the polylactic acid molecules oriented in the direction of 45 ° counterclockwise from the -Y direction when the sensor unit 11A is viewed in plan.

  And although the orientation direction of the molecule | numerator of polylactic acid is the same as the film 1, the film 2, the film 3, and the film 4, respectively, the composition of polylactic acid differs. The film 1 and the film 4 are respectively made of PDLA, and the film 2 and the film 3 are respectively made of PLLA. PLLA and PDLA are in an enantiomeric relationship. Therefore, in the case where the molecular orientation directions are the same, when distortion (stretching or contraction) in the same direction occurs in the film made of PLLA and the film made of PDLA, the directions of generated charges are opposite to each other.

  As shown in FIG. 4, for example, when the insole 51 on the side of the film 1 is stretched in the width direction (Y direction and -Y direction), the film 1, the film 2, the film 3 and the film 4 are stretched in the width direction. Distortion occurs.

  Since the film 1 and the film 2 are integrated, they have substantially the same amount of extension. Further, since the film 3 and the film 4 are integrated, they have substantially the same amount of extension. However, since the film 3 and the film 4 are connected to the film 2 through the signal electrode 6, the amount of extension is smaller than that of the film 1 and the film 2.

  Since the film 1 is made of PDLA, the charge direction is upward when strain that expands in the width direction occurs. Since the film 2 is made of PLLA, the charge direction is in the downward direction when a strain extending in the width direction occurs. Since the film 1 and the film 2 have the same thickness and substantially the same amount of stretching, 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, the charge direction is in the downward direction when the strain extending in the width direction occurs. Since the film 4 is made of PDLA, the charge direction is upward when strain that expands in the width direction occurs. Therefore, the charge amount generated in the film 3 and the charge amount generated in the film 4 are also 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 curve 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, a distortion occurs that shrinks with respect to the film 2. On the contrary, when the film 2 is based on the bonding surface of the film 1 and the film 2, an extension distortion occurs with respect to the film 1. Accordingly, 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, when the film 3 is based on the bonding surface of the film 3 and the film 4, distortion occurs that shrinks with respect to the film 4. In addition, when the film 4 is based on the bonding surface of the film 3 and the film 4, an extension distortion occurs with respect to the film 3. Therefore, the film 3 has the charge direction upward, and the film 4 also has the charge direction upward. For this reason, the charge generated in the film 3 and the charge generated in the film 4 are added.

  The charges added in the film 1 and the film 2 raise the potential of the signal electrode 6 with respect to the reference potential electrode 5. The charges added in the film 3 and the film 4 raise the potential of the signal electrode 6 with respect to the reference potential electrode 7. Thus, a large potential can be obtained at the signal electrode 6.

  In this manner, the sensor unit 11 does not output when the insole 51 expands or contracts in the surface direction, and can detect only bending of the sole (deformation due to a load in the Z direction or -Z direction). It is possible to properly detect the change in load with respect to

  In the above example, PDLA is used for film 1 and film 4 and PLLA is used for film 2 and film 3. However, for example, PLLA (or PDLA) is used for all the films. The same function can be realized by arranging the stretching directions of the film 2 and the film 2 at right angles, and making the stretching directions of the film 3 and the film 4 orthogonal.

  In addition, the film 1 and the film 4 can be simplified to realize the same function more simply. In this case, as shown in FIG. 6A, when the insole 51 expands and contracts in the surface direction, the amount of charge generated in the film 2 and the amount of charge generated in the film 3 can be offset, and the expansion and contraction in the surface direction Can be canceled. Further, 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 may 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 have opposite directions of charges generated during extension and contraction.

  Further, 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 by the direction of the electric field applied in poling (polarization treatment).

  However, polylactic acid is not pyroelectric and is suitable for installation at a place where body temperature is transmitted, such as shoes. In addition, polylactic acid generates a charge according to a change in strain. Therefore, the direction of charge is reversed between when the foot lands and the insole 51 is pushed in and when the insole 51 is released from the push-up by raising the foot. As the walking measurement sensor, the timing of landing and the timing of floating can be separately detected by acquiring this change in load (change on the time axis). This makes it possible to detect, for example, precise motion such as toe lifting, toe landing, heel landing, or heel floating.

  FIG. 7A is a block diagram showing 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 formed of each film, a charge for canceling the 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 is 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 load related to the sensor unit 11A.

  By thus disposing the J-FET 103 in proximity to the piezoelectric element 101, the influence of noise can be reduced and the signal can be stabilized. An amplification circuit may be provided between the sensor unit 11A and the signal processing unit 25. Further, the signal processing unit 25 may be incorporated in each sensor unit.

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

  Next, FIG. 9 is a figure which shows the time change of the output signal of each sensor part. The horizontal axis of the graph shown in FIG. 9 is time, and the vertical axis is the detected value of the sensor (the value after A / D conversion).

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

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

  On the other hand, when the heel rises, the heel portion of the insole 51 is released from being pushed in and the load decreases. That is, the insole 51 of the heel portion shifts from the maximum load state (the state in which the weight is on) to no load. At this time, the sensor unit 11D disposed in the heel portion changes from a state of being curved in a protruding manner 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 the value of the positive peak.

  Then, when the toe is kicked out (when the toe rises), the insole 51 is released from the state where the toe portion is pushed in, and the load decreases. That is, the insole 51 of the toe portion shifts from the state of maximum load (the state in which the weight is on) to no load. At this time, the sensor unit 11A disposed in the toe portion changes from being bent in the -Z direction to a flat state. Therefore, as in the graph shown in FIG. 9, the output of the sensor unit 11A shows the value of the positive peak.

  The signal processing unit 25 may output the above output value of each sensor unit to the user terminal 30, as shown in FIG. 7A. The user terminal 30 is an information processing terminal (for example, a smartphone, a personal computer, etc.) owned by the user. The user terminal 30 performs, for example, a process of displaying a graph as shown in FIG. 9 on a display (not shown). In this way, the user can know the timing of lifting his toe, landing on the toe, landing on the heel, lifting of the heel, or the like.

  As shown in FIG. 9, when the heel lands, it is the timing at which the foot comes into contact with the ground first after the foot is completely floating, so the load changes greatly, and the output value of the sensor unit 11D Is big. On the other hand, when the toe lands, the change in load is small (the output value is relatively small) because the heel has already landed.

  Similarly, when kicking the toe, since it is the timing when the foot shifts to a completely floating state, the change in load is large, and the output value of the sensor unit 11A is large. On the other hand, when the heel is very large, the change in load is small (the output value is relatively small) because the toes are still in the state of landing. However, for example, when landing from the toe first, the negative peak value of the sensor unit 11A increases, and conversely, the negative peak value of the sensor unit 11D decreases.

  Also, for example, when a negative peak occurs in the sensor unit 11B disposed on the thumb side at a timing close to the timing when the toe lands, it is determined that a load is applied to the thumb side at the time of landing on the toe. Can. On the other hand, when a negative peak is generated in the sensor unit 11C disposed on the little finger side at a timing close to the timing when the toe lands, it is determined that a load is applied to the little finger side at the time of landing on the toe. Can.

  In this way, the gait measurement sensor can detect more precise motion than before.

  Moreover, as shown in FIG. 10, it is also possible to provide the sensors for measuring walking on both feet. FIG. 10A is a view of the shoe 100 viewed from the back side in the case of providing the sensors for measuring walking on the shoes of both feet. FIG. 10B is a block diagram of a sensor unit and a signal processing unit.

  In the shoe 100A for the right foot, the sensor unit 101A is installed at the toe portion, and the sensor unit 101B is installed at the heel portion. In the shoe 100B for the left foot, the sensor unit 101C is installed at the toe portion, and the 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 shown in FIG.

  The sensor unit 101A and the sensor unit 101B are connected to a first signal processing unit 25A built in a 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 a 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 25A and the second signal processing unit 25B add time information to the output signals of the respective sensor units, and output the result 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 by terminals provided in the respective signal processing units at the start of measurement). Thus, the output signals of the sensor units can be synchronized.

  FIG. 11 is a diagram showing a time change of output signals of each sensor unit in the case of providing a sensor for measuring walking on shoes of both feet. As shown in FIG. 11, by providing the sensors for measuring walking on the shoes of both feet, more precise movement can be detected. 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 balance on the left and right can be displayed on the user terminal 30. In addition, by measuring the timing of landing and kicking, the walking speed, the stride length of each foot, and the like can be measured and displayed on the user terminal 30.

  In the present embodiment, an example in which the sensor for measuring walking is installed on shoes is shown, but the sensor for measuring walking according to the present invention can be installed on footwear such as sandals, slippers or clogs. It is. Further, footwear integrated with a sensor for measuring walking is also within the technical scope of the present invention.

1, 2, 3, 4 ... film 5, 7 ... reference potential electrode 6 ... signal electrode 8 ... connection portion 11A, 11B, 11C, 11D ... sensor portion 21, 22 ... signal line 25, 25A, 25B ... signal processing portion 30 ... User terminal 31 ... Shoe sole 51 ... Insole 100, 100A, 100B ... Shoes

Claims (5)

A displacement detection film attached to a place deformed by being pressed by a sole ;
A signal processing unit that processes an output signal of the displacement detection film;
And a signal electrode ,
The displacement detection film performs an output according to a time change of load due to the pressing, and a pair of first piezoelectric film and a second piezoelectric film disposed adjacent to each other , and a pair of first piezoelectric films disposed adjacent to each other 3 with a piezoelectric film and a fourth piezoelectric film,
In the first piezoelectric film and the second piezoelectric film, the directions of charges generated at the time of expansion and contraction are opposite,
It said third piezoelectric film and said fourth piezoelectric film up direction reverse der charges generated during stretching,
The signal electrode is provided between the first piezoelectric film and the second piezoelectric film, and the third piezoelectric film and the fourth piezoelectric film, and detects the output signal.
In the first piezoelectric film and the second piezoelectric film, and the third piezoelectric film and the fourth piezoelectric film, the directions of charges generated at the time of pressing application and at the time of pressing release are different,
The signal processing unit is configured to calculate a direction of charge generated by each of the first piezoelectric film, the second piezoelectric film, the third piezoelectric film, and the fourth piezoelectric film based on the output signal detected by the signal electrode. and gait measurement sensor characterized that you determine the gait of the foot based on a temporal change in the charge.   The sensor according to claim 1, wherein the first piezoelectric film, the second piezoelectric film, the third piezoelectric film, and the fourth piezoelectric film include polylactic acid. Wherein the signal processing unit, the walking measuring sensor according to claim 1 or 2 for adding the time information to the 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 walk measuring system according to any one of claims 1 to 3, wherein the first signal processing unit and the second signal processing unit each include an internal clock and a terminal for synchronizing the internal clock. Sensor. Footwear comprising the sensor for measuring walking according to any one of claims 1 to 4 .

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