JP4374596B2 - Load measurement method - Google Patents

Description

The present invention relates to a technique for measuring a load distribution and a load change on a sole. In particular, it relates to the following technical fields.
1. Measure the size and weight distribution of the prosthetic leg and the handicapped with the prosthetic limbs on the road surface, and show the change in weight over time.
2. A small load sensor is attached to the tread to know the load against the ground of the bottom of the golf shoe, the distributed load on the tread during club swing, the horizontal kick force is measured over time, the maximum distributed load and the weight shift are measured and the time Know the trajectory of each change.
3. A person with a walking disability should wear shoes with load sensors distributed on the sole and measure the weight distribution on the tread surface during walking and display the change in position of the maximum load.
4. Running distance To analyze the kicking force and the direction and magnitude of the runner at the start.
5. Carry a load with both arms and place a number of thin load sensors on the sole, wear the second sole that you wear, and measure the load acting on the ground from the load sensor.
6. When measuring the weight of an item by holding it in your hand, open your hands and place multiple thin, small load sensors on the top of your fingers and palm, and put these gloves on your hands. Place the item on top of it, lift it up, and measure the weight on both hands from the load sensor.

  For measuring the weight of a prosthetic leg or handicapped person during walking, a method of detecting the air pressure in the air bag as an electric signal with a pressure sensor and reading the pressure with an electric indicator is disclosed in JP-A-2002-90216 (Patent Document 1). Yes.

However, the method described in Patent Document 1 always shows only the weight applied to the entire sole. Therefore, there is a problem in that it is not possible to distinguish between the weight of the prosthetic leg of the handicapped person and the weight distribution of the leg surface during walking.
In addition, this method is further inconvenient with respect to the prosthetic leg tread surface. This is because the attachment angle of the artificial leg and the suitability of the joint surface with the thigh are unknown.
There is no way to attach a detector directly to the tread during actual running, golf swing, or walking with a walking handicapped to measure weight distribution pressure or analyze load on the tread. There is something that is expensive and similarly removes a part on the floor side, inserts a large three-part force sensor into it, and measures from the reaction force of the kick force, but the stride is necessary when running This is inconvenient because it does not match the trapezoidal three component force sensor.
When multiple load sensors are used to measure the tread surface distribution, at most 10 or more shoes are required for a single leg shoe sole. Therefore, if a load sensor for measuring the load only in the vertical direction that is currently on the market is investigated, for example, if a product with an outer diameter of 12 mm and a thickness of 4 mm is used with a rated load of 5 kg, the total is 33,000 yen. Since 10 of these are used on the soles, it costs 660,000 yen for both legs.
As described above, the conventional technique has a cost problem in addition to a structural problem.

  Therefore, the present invention provides a load measuring method that can be mass-produced by mold molding and can be provided at a low cost in consideration of the use of a large number of sensors, and a shoe with a load measuring sensor that does not have a sense of incongruity used in the method. The purpose is that.

  The inventor of the present application has already applied for a contact pressure sensor (3-component load sensor) in Japanese Patent Application No. 2003-036504, and to what extent various characteristics should be satisfied before manufacturing a contact pressure sensor with a final dimension of 1 mm in height. A five-fold model (Fig. 1) was manufactured and investigated. Figure 1 shows its appearance. The sensor has a height of 9 mm and a diameter of 10 mm so that a disc is supported by four legs at the center of a square with a side of 25 mm. A total of 36 pieces were produced as these three components. According to the load calibration test results, for example, if 12 pieces are observed, the non-linearity is 0.07% to 0.45% and the hysteresis is 0.01% to 0.229% with respect to the rated load of 5 kg except for 1.27% of one piece. The output strain was 1588 × 10-6 to 2007 × 10-6. From this result, knowledge that a load cell having a thickness of about 3 mm can be manufactured is obtained, and the present invention is achieved.

That is, the load measuring method of claim 1 of the present invention is:
By arranging a plurality of three-component force sensors on the sole and analyzing the signals from each of the three-component force sensors, the vertical component of the load on the sole and two directional components orthogonal to each other in the horizontal plane are obtained. In the load measurement method to measure,
As the three-component load sensor,
The structure extends from the first disc-shaped strain generating portion into a plate shape from a position divided into four at approximately the same angle, and serves as a leg of the disc-shaped strain generating portion to support the first strain generating portion. The four-direction leg has the shape of a three-component force sensor that becomes the second strain -generating portion, the diaphragm-shaped first strain gauge on the back surface of the first disk-shaped strain-generating portion, and the four-direction leg second It is characterized by using a three-component force sensor with a second strain gauge attached only to the front or back side.
In addition, a sole part means the part corresponding to the sole of footwear, such as shoes, slippers, and socks. Also, 3 and the component force load sensors, refers to a sensor that can measure the three axes X, Y, load component in the Z-direction at least orthogonal.

According to the load measuring how the present invention, weight and its distribution load legs tread not possible with conventional, since it is possible to Kechikara measurement, appropriate prosthesis by more accurate diagnosis for the prosthetic foot's The effect that can be obtained, the weight shift at the time of golf swing, how to apply weight before and after, etc. can be visually discerned, the effect that it is possible to practice effectively, and in the case of running athletes Since the transition of the kicking force (spring force) at the time can be discriminated, an effect of enabling effective practice is obtained.

(Structure 1, load sensor mounted on the sole)
Fig. 2 shows the structure of the load sensor used in the present invention. The load sensor 1 uses a thin brass plate having a thickness of about 1 mm, a phosphor bronze plate, a white plate, or an aluminum alloy plate. Diaphragm strain gauges Rt1, Rc1, Rt2, and Rc2 are bonded to the back of the circular plate 10, and the load in the Z direction is measured. Then, two elements are attached to the front and back of the four legs 11, 13, 12, and 14, respectively. Single-axis strain gauges Rt3, Rc3, Rt4, Rc4, Rt5, Rc5, Rt6, Rc6 are bonded, load in X direction is measured with strain gauges Rt3, Rc3, Rt4, Rc4, load in Y direction is strain gauge Rt5 , Rc5, Rt6, Rc6.
As shown in FIGS. 2B and 2C,
Rt1, Rc1, Rt2, Rc2, are attached to the back of the circular plate 10, Rc3, Rc4, Rc5, Rc6 are attached to the upper part of the four legs 11, 13, 12, 14, and Rt3, Rt4, Rt5, Rt6 are attached to the lower part. Yes. Reference numeral 5 denotes a force transmission rod inserted into the hole 15 at the center of the load sensor 1.

When a force P perpendicular (Z direction) is applied to the surface of the circular plate 10, as shown in FIG. 3 (d), Rc1 and Rc2 are compressive strains corresponding to the radial stress σr, and Rt1 and Rt2 are circumferential directions. It receives a tensile strain corresponding to the stress σc.
Due to the vertical force P, that is, the downward force (Z direction) P shown in FIG. 2B, the strain gauges Rt1, Rt2 bonded to the back surface of the circular plate 10 are subjected to tensile strain, and the strain gauges Rc1, Rc2 is arranged so as to receive a compressive strain.

  Strain gauges Rt3 and Rt4 are subject to tensile strain and strain gauges Rc4 and Rc3 are subject to compressive strain when a force parallel to the circular plate 10 is applied in the right direction (X direction) shown in FIG. The legs 11 and 13 are disposed on the front and back surfaces, respectively.

  The strain gauges Rt5 and Rt6 when the force parallel to the circular plate is applied in the forward direction (Y direction) shown in FIG. 2 (b), that is, the right direction (Y direction) shown in FIG. Accordingly, the strain gauges Rc5 and Rc6 are respectively disposed on the front and back surfaces of the legs 12 and 14 so as to receive the compressive strain.

These strain gauges constitute a Wheatstone bridge as shown in FIGS. 3A, 3B, and 3C in the X, Y, and Z directions.
That is, the strain gauges Rt1, Rc1, Rt2, and Rc2 constitute one Wheatstone bridge to detect the load in the Z direction and make it less susceptible to the load in the X and Y directions. The strain gauges Rt3, Rc3, Rt4, and Rc4 make up one Wheatstone bridge, which detects the load in the X direction and is less susceptible to the effects of the load in the Z and Y directions. The strain gauges Rt5, Rc5, Rt6, and Rc6 make up one Wheatstone bridge to detect the load in the Y direction and make it less susceptible to the load in the X and Z directions.
3 (a), (b), and (c), symbol E indicates an applied voltage of a predetermined constant voltage, and symbol e indicates an output voltage that is output as a result of the resistance change of each strain gauge according to the load. Show.
These four legs 11, 12, 13, 14 of the load sensor are fixed at the ends by the bottom plate 2 and the rivets 3.

Fig. 4 shows how to install each load sensor.
The force transmission rod 5 is inserted into the small hole 41 provided in the second shoe sole back surface 4, the urethane rubber sheet 6 is sandwiched between them, and an adhesive is applied to both surfaces, and is inserted into the hole 15 at the center of the load sensor. In this way, the second shoe sole 4 and the load sensor 1 are fixed.

The placement and quantity of each load sensor is determined by the purpose of measuring the force. For example, FIG. 5, FIG. 6, and FIG. 7 are suitable methods for measuring the weight of a golf shoe, the weight generated on the tread, and the weight by lifting the load. The shoe 9A with a load sensor shown in FIG. 7 will be described.
In this method, a thick convex portion 71 is formed on the grounding shoe sole 7 so as to be substantially the same size as the load sensor 1 and divided into one surface. The arrangement position interval “l”, “h” of the load sensor 1 is clearly set, and the position designation when observing the subsequent weight distribution chart is made possible. The load sensor 1 is installed at a position directly above it. FIG. 5 is a diagram viewed from directly above the load sensor with the second shoe sole removed, and is an explanatory diagram showing the convex portion 71 of the grounding shoe sole 7 by a dotted line.
FIG. 8 is an explanatory diagram of a load sensor-equipped shoe 9A configured by attaching a second shoe sole to a normal shoe.

(wiring)
The wiring network flexible substrate F is shown in FIG.
FIG. 9A shows the first layer F1 of the flexible wiring board, which is composed of a lead wire for the applied voltage E in the X direction of the load sensor 1 in FIG. 7 and four lead wires for the output voltage e. .
FIG. 9B shows a second layer F2 of the flexible wiring board constituted by the lead wire for the applied voltage E in the Y direction of the load sensor 1 and four lead wires for the output voltage e.
FIG. 9C shows a third layer F3 of the flexible wiring board constituted by the lead wire for the applied voltage E in the Z direction of the load sensor 1 and four lead wires for the output voltage e.

As shown in FIG. 11 (d), the lengths D1 and D2 are respectively shortened and stacked, and the lead lines for the applied voltage E in the three directions X, Y, and Z of the sensor 1 and the output voltage e are drawn. Lines are integrated. The same method is used for other load sensors.
In another load sensor shown in FIGS. 10A, 10B and 10C, the layers F1, F2 and F3 are integrated so as to avoid the wiring of the load sensor 1. In the wiring board of the load sensor 3 shown in FIGS. 11A, 11B, and 11C, similarly, the layers F1, F2, and F3 are integrated by avoiding wiring between the load sensor 1 and another load sensor. To do.
The terminal of each flexible board is connected to a small connector 82 shown in FIG. 7, and further connected to a small connector board shown in FIG.

(Connected to the sole plate)
As shown in FIG. 8, the outer peripheral stopper 72 of the grounding shoe sole 7 is fitted around the original shoe sole 41, and a belt is used as necessary (not shown) to connect the grounding shoe sole 7 and the original shoe. The bottom 41 is integrated. The second shoe sole 4 and the ground contact shoe sole 7 are filled and connected with a felt cloth 21 shown in FIG. 6 except for the sensor portion. Further, in order to maintain waterproofness, an elastic rubber material (not shown) is attached to the periphery of the second shoe sole 4 so as to be fitted on the outer periphery of the original shoe sole 41 and tightened.

(From small connector to data processor)
As shown in FIGS. 7 and 8, the flexible board F is extended to the side of the shoe, relayed to the small connector 82 by the multi-core wire 81, and the sensor connection connector board 84 built in the cloth stamp 83 is attached to the ankle by the belt 86. Installing. This sensor connector board 84 incorporates a preamplifier, A / D conversion means and the like as necessary. The sensor connection connector board 84 is further connected to an amplifier, a switch, and an A / D conversion circuit as required by a multicore cable 85. The measurement data is displayed on an indicator according to the required purpose, stored in a storage medium such as a memory circuit or an IC card, and further recorded in an external computer at off-time. When measuring in real time, a transmitter is built in and a digital signal is transmitted, a receiver is placed outside, and the signal can be received and recorded in an external computer. This state is only 5 to 10 mm higher than the actual shoe sole, and the measurement subject can measure without any change from the normal walking state.
In the case of body weight measurement, a sensor group attached to the second shoe sole is worn on both legs, a small connector board on the ankle part, connected to a data processor on the waist part, and an indicator attached to the belt, , Display right leg load and left leg load.

(Weight distribution measurement)
When measuring in real time, connect to the indicator and transmitter (with a transmitter and small battery) attached to the waist with a multicore cable. For example, it is converted to RS232C and connected to an external computer on the receiving side, and a distribution diagram is displayed in time series in a cubic form or by color for each body weight.
For off-time measurement, if a function to attach an IC card is attached, the transmitter is omitted and the walking is completed.

The structure of the shoe 9B with load sensor shown in FIGS.
(Structure 2: Built-in load sensor on insoles)
First, a method will be described in which a shoe insole shape is used and a load sensor is installed in the inside of the shoe for measurement. This method is used for sports shoes with a flat shoe ground surface.
As shown in FIGS. 12 and 13, the metal plate 92 with burrs is pressed against the upper skin of the thin plastic plate 91 to cause the burrs to bite into the thin plastic plate 91. The metal plate 92 with burr and the center of the disc 95 of the load sensor 90 with the bottom plate 94 are connected by the force transmission rod 93. In this state, the flexible substrate has already been pulled out in a direction perpendicular to the length direction of the legs. Therefore, a plurality of load sensors are arranged in order on the floor covering.
Fig. 14 shows the situation where a metal plate with burrs is placed. At this time, the position of the load sensor is restricted by “l” and “h” so that the load distribution diagram can be observed in the figure at the position of the foot surface. The gap between the load sensors is filled with felt cloth 21 and further covered with a cotton cloth 96 bag. This situation results in a cover with a thickness of about 5 mm. The small connector is placed on the side of the ankle, and is bent by a flexible substrate at a right angle from the second shoe sole method and connected. In this case as well, as in (Structure 1), data is instructed and data acquisition is processed by a device attached to the waist.

It is a three-dimensional view of the 3 component force load sensor used for this invention. It is explanatory drawing of the 3 component force load sensor used for this invention. 2A is a plan view of the three-component force load sensor, FIG. 2B is a side view of the three-component force sensor, and shows a cross section taken along line AA in FIG. ing. FIG. 2C is a side view of the three-component load sensor, and shows a cross section taken along line BB in FIG. FIG. 3A is a connection diagram of a strain gauge Wheatstone bridge in the Z direction, and FIG. 3B is a Wheatstone bridge of a strain gauge in the X direction. FIG. 3C is a connection diagram of a Wheatstone bridge of a strain gauge in the Y direction. FIG. 3D is an explanatory view of the operation of the strain gauge. It is a connection figure of a 2nd shoe sole and a load sensor. It is the figure which removed the 2nd shoe sole and was seen from right above the load sensor, and the figure which expressed the convex of the contact shoe sole with the dotted line. It is the figure which showed the load sensor mounting position and the convex position of a grounding shoe sole. It is the figure which has arrange | positioned the load sensor to the 2nd shoe bottom face, and showed small connector attachment. It is the figure which connected the 2nd shoe sole to the original shoe sole. It is the flexible substrate of the load sensor 1 arranged first. FIG. 9A shows the first layer flexible substrate. FIG. 9B shows the second layer flexible substrate, and FIG. 9C shows the third layer flexible substrate. This is a flexible substrate of the load sensor 2 arranged second. 10A shows the first layer flexible substrate, FIG. 10B shows the second layer flexible substrate, and FIG. 10C shows the third layer flexible substrate. This is a flexible substrate of the load sensor 3 arranged third. 11A shows the first layer flexible substrate, FIG. 11B shows the second layer flexible substrate, and FIG. 11C shows the third layer flexible substrate. FIG. 11 (d) is a diagram showing a state in which each flexible substrate is stacked. It is the figure which showed the cross-sectional side surface of the attachment of the load sensor made into the covering method. It is the figure which showed the connection of a thin plastic board (overlay skin) and a load sensor. It is the figure which arranged and attached the metal plate with a burr | flash to a thin plastic board (overlay skin).

Explanation of symbols

1 3 component force sensor
10 First straining part
11,12,13,14 Second strain generating part Rc1, Rt1, Rc2, Rt2 First strain gauge
Rc3, Rc4, Rc5, Rc6, Rt3, Rt4, Rt5, Rt6 Second strain gauge 9A, 9B Shoe with load sensor 4 Second shoe tread
15 Hole in the center of the 3-component load sensor disk
41 Small hole 5 on the back of the second shoe sole treading force transmission rod Rc1, Rt1, Rc2, Rt2, Rc3, Rc4, Rc5, Rc6, Rt3, Rt4, Rt5, Rt6 Strain gauge F Flexible substrate
91 thin plastic plate
92 Drilled burr disc

Claims (1)

By arranging a plurality of three-component force sensors on the sole and analyzing the signals from each of the three-component force sensors, the vertical component of the load on the sole and two directional components orthogonal to each other in the horizontal plane are obtained. In the load measurement method to measure ,
As the three-component load sensor,
The structure extends from the first disc-shaped strain generating portion into a plate shape from a position divided into four at approximately the same angle, and serves as a leg of the disc-shaped strain generating portion to support the first strain generating portion. The four-direction leg has the shape of a three-component force sensor that becomes the second strain -generating portion, the diaphragm-shaped first strain gauge on the back surface of the first disk-shaped strain-generating portion, and the four-direction leg second A load measuring method characterized by using a three-component force sensor in which a second strain gauge is attached only to the front or back of the above .

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