JP2012150075A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor capable of clearly sensing a state of getting on a bed and leaving a bed of a sole of a user of a walking assist device.SOLUTION: A pressure sensor comprises a pressure-sensitive sheet changing surface resistance due to pressure, and an electrode sheet provided with at least two electrodes; and is configured by superimposing one surface of the pressure-sensitive sheet and one surface of the electrode sheet. The two electrodes are provided at different positions on the surface of the electrode sheet, and provided so as to measure resistance in an area including the surface which is the surface of the pressure-sensitive sheet and positioned between the two electrodes. Spacers having predetermined thickness in a vertical direction to the surface of the electrode sheet are respectively provided around the electrodes.

Description

  The present invention relates to the technical field of a sheet-like pressure sensor used, for example, as an insole for shoes.

  In recent years, rehabilitation has been performed in a state where a walking assist device using a driving source is mounted on, for example, a knee disease patient (see, for example, Patent Document 1). The walking assist device assists the wearer by continuously giving a predetermined walking pattern to the wearer as a patient. Thus, the wearer can walk independently so as to follow the movement. However, the wearer may not be able to follow during this rehabilitation or may become unstable walking against his / her intentions due to wandering. Therefore, a walking assist device that gives the wearer a walking pattern according to the walking state of the wearer is desired. In order to know the walking state of the wearer, for example, how to apply the load on the user's foot, balance, wobble, etc., for example, a pressure distribution sensor having a pressure detection region in which a number of pressure sensitive sensors are arranged in a grid Can be used (see, for example, Patent Document 2).

JP 2002-301124 A JP 2010-69227 A

  However, since the technique of Patent Document 2 is performed within a limited size on the pressure distribution sensor, it is difficult to apply the technique of Patent Document 2 to a walking assist device rather than a continuous walking. On the other hand, it is conceivable to use the pressure distribution sensor disclosed in Patent Document 2 as, for example, an insole for a rehabilitation shoe of a wearer of a walking assistance device. However, since the pressure distribution sensor disclosed in Patent Document 2 includes a number of pressure sensors and a pressure detection unit connected to each pressure sensor, such a pressure distribution sensor is used as an insole for rehabilitation shoes. If used, it may be uncomfortable for the wearer wearing the rehabilitation shoes, and may hinder effective rehabilitation. In addition, when a cushion is provided on the pressure distribution sensor in order to eliminate a sense of incongruity, it becomes difficult for the pressure sensitive sensor to sense pressure from above (that is, the wearer's foot).

  Furthermore, in assisting the wearer's walking with the walking assist device, it is important to control the knee joint motor and the like. In order to allow the wearer to perform this control without difficulty, a pressure sensor that can clearly detect the state of landing and leaving of the foot of the wearer has been desired, but such a pressure sensor is known. It wasn't.

  Therefore, the present invention has been made in view of the above points, and it is an object to provide a pressure sensor that can clearly sense the state of landing and getting off of the sole of the wearer of the walking assistance device. One of them.

  In order to solve the above-mentioned problem, the invention described in claim 1 includes a pressure-sensitive sheet whose surface resistance is changed by pressure, and an electrode sheet provided with at least two electrodes, and one surface of the pressure-sensitive sheet. And the one surface of the electrode sheet, the two electrodes are provided at different positions on the surface of the electrode sheet, and the surface of the pressure sensitive sheet And a resistance of a region including the surface located between the two electrodes is provided so as to be measurable, and a spacer having a predetermined thickness in a direction perpendicular to the surface of the electrode sheet, It is provided around the electrode.

  According to a second aspect of the present invention, in the pressure sensor according to the first aspect, the spacer is formed integrally with the electrode sheet.

  According to a third aspect of the present invention, in the pressure sensor according to the first or second aspect, the pressure sensor is used as an insole for a shoe.

  According to the present invention, by providing the spacer around the electrode, it is possible to clearly sense the landing state and the leaving state of the sole of the wearer.

It is a figure which shows the structure of a sole sensor. It is a conceptual diagram at the time of measuring the surface resistance of the pressure sensitive sheet of a sole sensor. It is sectional drawing of a sole sensor. It is a figure which shows the voltage waveform from a sole sensor, a knee joint angle sensor, etc. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In addition, embodiment described below is embodiment when the pressure sensor which concerns on this invention is applied to a sole sensor. The sole sensor according to the present embodiment is used as an insole for rehabilitation shoes. Then, a wearer of a walking assistance device (not shown) wears rehabilitation shoes to perform rehabilitation.

  First, with reference to FIG. 1 thru | or FIG. 3, the structure of the foot sensor which concerns on this embodiment is demonstrated. FIG. 1 is a diagram showing a configuration of a sole sensor. FIG. 2 is a conceptual diagram when the surface resistance of the pressure-sensitive sheet of the sole sensor is measured. FIG. 3 is a cross-sectional view of the sole sensor.

  As shown in FIG. 1, the sole sensor 1 according to the present embodiment includes a pressure-sensitive sheet 11 whose surface (surface) resistance is changed by pressure, and an electrode sheet 12 provided with at least two electrodes. One surface of the pressure sheet 11 and one surface of the electrode sheet 12 are configured to overlap each other. Specifically, the sole sensor 1 is formed by inserting the pressure sensitive sheet 11 on the electrode sheet 12 after the electrode sheet 12 is inserted into the rehabilitation shoe. As shown in FIG. 2, it is desirable to apply a cushioning material whose resistance changes by being pressurized from above as shown in FIG. 2. Thereby, it becomes possible to walk without giving an uncomfortable feeling to the wearer wearing the rehabilitation shoes, and the durability of the electrode sheet 12 can be increased.

  On the other hand, the electrode sheet 12 is made of, for example, FPC (Flexible Printed Circuits), and is configured by laminating copper as an electrode on polyimide as an insulator (in the electrode sheet 12 alone, the electrodes are insulated by polyimide). ing. Polyimide keeps its shape as an insole for rehabilitation shoes, eliminates misalignment, and increases durability. The exposed electrode is treated with gold plating or the like to prevent deterioration due to rust under moisture or high humidity.

  In the example shown in FIG. 1, the pressure sensitive sheet 11 is divided into four regions A1 to A4, and the electrode sheet 12 is provided with a pair of electrodes facing each region. As shown in FIG. 1, the pair of electrodes is provided at different positions on one surface of the electrode sheet 12, and is one surface of the pressure-sensitive sheet 11 between the pair of electrodes (for example, 122 and The resistance of a region including a surface located between the two electrodes (that is, this region is sandwiched between a pair of electrodes) is provided so as to be measurable. Here, the region A1 is adapted to hit the buttocks of a wearer who wears rehabilitation shoes, and the pair of electrodes 122 and 123 are opposed to the region A1. The resistance (in other words, voltage) of the region including the surface located between the pair of electrodes 122 and 123 is measured by a walking assist device (not shown) to sense the pressure on the buttocks of the wearer's sole. be able to.

  In the example shown in FIG. 1, among the pair of electrodes at the measurement positions of the divided areas, the electrodes 123, 125, 127, and 129 are connected to form a common ground. Thereby, the number of wirings and routing can be reduced. Moreover, as shown in FIG. 1, the wiring (copper wire) 130 connected to each electrode is electrically connected to the control unit of the walking assistance device via the relay connector 131. Thereby, the walking assistance device can perform control to give the wearer a walking pattern corresponding to the walking state of the wearer. In the example shown in FIG. 1, the pressure-sensitive sheet 11 is divided into a plurality of regions, and a plurality of measurement points are set by providing a pair of electrodes for each of the divided regions. Only a pair of electrodes 122 and 123 may be provided. Moreover, in the example shown in FIG. 1, each electrode 122-129 is circular shape, However, Other shapes may be sufficient.

  In the sole sensor 1 according to the present embodiment, as shown in FIG. 3, spacers 13 having a predetermined thickness α in a direction perpendicular to one surface of the electrode sheet 12 are provided around each electrode. Is provided. Here, the thickness α of the spacer 13 is preferably about 0.25 mm, for example. However, the thickness α is preferably changed between 0.2 mm and 0.8 mm, for example, depending on the load applied to the spacer 13 (the weight of the wearer). Such a spacer 13 is for changing the contact state between the sole and the sole sensor 1 with respect to the landing state and the leaving floor state of the wearer's sole and clarifying the same state. The spacer 13 is bonded to one surface of the electrode sheet 12, for example. In this case, the material of the spacer 13 is not particularly limited, but for example, an insulator such as PET (Polyethylene Terephthalate), which is not deformed as much as possible, is desirable. Further, when bonding to one surface of the electrode sheet 12, if the area of the bonding surface is small, there is a possibility that positional displacement occurs due to a load, so it is necessary to secure a certain bonding surface. In this case, the radial thickness β of the spacer 13 is preferably about 5 mm, for example. In addition, the spacer 13 may be formed by cutting out a portion where the electrode is located in the electrode sheet 12. In this case, the spacer 13 is formed integrally with the electrode sheet 12 (for example, formed in one layer). For this reason, no displacement occurs, and the spacer 13 can be made more stable.

  As described above, by providing the spacer 13 around the electrode provided on the electrode sheet 12, a step is formed between the electrode and the periphery of the electrode, and the electrode does not exceed the predetermined load with respect to the foot load. A function to stop touching occurs. Therefore, in the walking assist device, when the electric signal from the sole sensor 1 is used as a control trigger, the steepness is assumed when the wearer's sole comes off the floor or when the wearer leaves the floor. Thus, a remarkable resistance change (in other words, a voltage change) is born, which is effective as a switch. Therefore, it is possible to clearly sense the state of landing and getting off of the foot of the wearer (in other words, the judgment of landing and getting off is easy). As a result, the walking assist device controls the knee joint motor and the like so as to assist the wearer's walking when the wearer leaves the floor of the foot of the foot of the wearer or when the foot of the wearer leaves the floor. Can be done more effectively.

  FIG. 4 is a diagram showing voltage waveforms from a sole sensor, a knee joint angle sensor, and the like. In the example shown in FIG. 4, the spacer 13 is provided in the sole sensor for the left foot, while the spacer 13 is not provided in the sole sensor for the right foot. As can be seen from FIG. 4, the voltage waveform from the sole sensor for the left foot is longer than the voltage waveform from the sole sensor for the right foot. It has become.

  If the spacer 13 is not provided on the sole sensor, or if the spacer thickness α is thin, the foot sensor will be deformed and take time to return to the original condition if the wearer's sole landing state continues. Even if it becomes a state, it is recognized as a landing state (because the wearer raises his / her foot, the electrode and the pressure-sensitive sheet are not immediately separated), and effective operation becomes difficult. However, if the spacer 13 having an appropriate thickness α is provided around the electrode as described above, more effective operation is possible, and it can be used as a control trigger in the walking assist device, and continuous walking is possible.

  In the above embodiment, the case where the pressure sensor of the present invention is applied to the sole sensor has been described as an example. However, the pressure sensor may be applied to other sensors.

1 Foot sensor 11 Pressure sensitive sheet 12 Electrode sheet 13 Spacer

Claims (3)

A pressure-sensitive sheet whose surface resistance is changed by pressure; and an electrode sheet provided with at least two electrodes, wherein one surface of the pressure-sensitive sheet and one surface of the electrode sheet overlap each other. In the pressure sensor,
The two electrodes are provided at different positions on the surface of the electrode sheet, and the resistance of a region including the surface which is the surface of the pressure-sensitive sheet and is located between the two electrodes is measured. Is possible,
A pressure sensor, wherein a spacer having a predetermined thickness in a direction perpendicular to the surface of the electrode sheet is provided around each of the electrodes.   The pressure sensor according to claim 1, wherein the spacer is formed integrally with the electrode sheet.   The pressure sensor according to claim 1, wherein the pressure sensor is used as an insole for shoes.