Contact detecting sensor

Abstract

A contact detecting sensor (100) is provided with a sensor unit (1) that detects contact while alleviating impacts during contact, the sensor unit (1) comprising an expanding / contracting sensor (2).

Description

Contact detection sensor

[0001] The present invention relates to a contact detection sensor.

[0002] Bumper sensors or bumper switches are installed on the exterior of the body of an unmanned vehicle, etc., for the purpose of obstacle detection. For example, Patent Document 1 describes an example of such a bumper sensor or bumper switch that is attached to an unmanned vehicle and uses a vibration / impact detection sensor as the sensor unit.

[0003] Utility Model Registration No. 3144158

[0004] However, the bumper switch described in Patent Document 1 typically has a cushioning material on the surface of the sensor to absorb impacts, and in order to detect contact with an obstacle, the cushioning material needs to be pushed all the way in. This causes a problem of reduced response sensitivity.

[0005] An object of the present invention is to provide a contact detection sensor with high response sensitivity.

[0006] [1] A contact detection sensor including a sensor unit that detects contact while absorbing impact at the time of contact, the sensor unit including an expansion sensor.

[0007] [2] The contact detection sensor according to [1], wherein the sensor unit further includes a flexible member that deforms under pressure to absorb impact, and the stretch sensor is provided closer to the contact surface of the sensor unit than the flexible member.

[0008] [3] The contact detection sensor according to [1] or [2], wherein the sensor unit further includes a skin material provided on a surface side of the stretch sensor.

[0009] [4] The contact detection sensor according to any one of [1] to [3], wherein the stretch sensor comprises: a stretchable member having stretchability; an electrode portion including a conductive linear body; and a wiring portion electrically connected to the electrode portion and including a conductive linear body.

[0010] [5] The contact detection sensor according to [4], wherein the stretch sensor includes two electrode portions, a first electrode portion and a second electrode portion, and two wiring portions, a first wiring portion and a second wiring portion, the stretchable member is a cloth material, and when the resistance value between the first electrode portion and the second electrode portion is measured while the cloth material is stretched, the measured value changes.

[0011] [6] The contact detection sensor according to [4] or [5], wherein the conductive linear body is a linear body including a carbon nanotube.

[0012] [7] The contact detection sensor according to any one of [4] to [6], wherein when the stretch sensor detects contact, the stretch rate of the stretchable member is 10% or more and 50% or less.

[0013] [8] The contact detection sensor according to any one of [1] to [7], wherein when the stretch sensor detects contact, the detection depth of the stretch sensor is 5 mm or more and 40 mm or less.

[0014] [9] The contact detection sensor according to any one of [1] to [8], wherein the stretch sensor is in a conducting state when not in contact and in a non-conducting state when in contact.

[0015] According to one aspect of the present invention, a contact detection sensor with high response sensitivity can be provided.

[0016] Fig. 2 is a schematic diagram showing a contact detection sensor according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing the II-II cross section of Fig. 1. Fig. 4 is a schematic plan view showing an expansion sensor used in an embodiment of the present invention, showing the expansion sensor before expansion. Fig. 5 is a schematic plan view showing an expansion sensor used in an embodiment of the present invention, showing the expansion sensor when expanded.

[0017] [Embodiments] The present invention will be described below with reference to the drawings, taking embodiments as examples. The present invention is not limited to the contents of the embodiments. Note that in the drawings, some parts are illustrated enlarged or reduced in size for ease of explanation.

[0018] (Contact Detection Sensor) As shown in FIGS. 1 and 2 , the contact detection sensor 100 according to this embodiment includes a sensor unit 1 equipped with an expansion sensor 2 and wiring 5 electrically connected to the expansion sensor 2. The sensor unit 1 detects contact while absorbing impacts at the time of contact. Information detected by the sensor unit 1 is measured by a measuring device (not shown) via the wiring 5. The inventors believe that the reason why the contact detection sensor 100 according to this embodiment can achieve high response sensitivity is as follows. Conventional bumper switches use vibration / impact detection sensors as their sensor units, but typically require cushioning material on the surface of the sensor unit to absorb impacts. In contrast, the expansion sensor 2 can absorb impacts by expanding and contracting even when directly subjected to impacts, eliminating the need for cushioning material on the surface of the expansion sensor 2. This eliminates the need for cushioning material on the surface of the expansion sensor 2. Therefore, response sensitivity can be improved compared to conventional methods. Furthermore, vibration / impact detection sensors used in conventional bumper switches have the problem of causing pain when a person bumps into them. In contrast, the expansion sensor 2 used in this embodiment is soft and does not encounter this problem.

[0019] (Stretch Sensor) The stretch sensor 2 is not particularly limited as long as it is a stretchable sensor that can detect stretching, and any known stretch sensor can be used as appropriate. However, from the viewpoint of having excellent flexibility and stretchability and sufficient durability, the stretch sensor 2 preferably includes a stretchable member 21 having stretchability, a first electrode portion 221A including a conductive linear body 22, and a first wiring portion 222A that is electrically connected to the first electrode portion 221A and includes the conductive linear body 22, as shown in FIG. 3A .

[0020] The stretch sensor 2 preferably has the configuration shown in FIG. 3A . That is, the stretch sensor 2 includes a stretchable member 21, a first electrode portion 221A including a conductive linear body 22, a second electrode portion 221B including the conductive linear body 22, and a first wiring portion 222A including the conductive linear body 22 and a second wiring portion 222B including the conductive linear body 22, which are electrically connected to the first electrode portion 221A and the second electrode portion 221B, respectively. In the stretch sensor 2, the conductive linear body 22 is formed in a wave-like shape in a plan view and extends across the first electrode portion 221A and the second electrode portion 221B. The first electrode portion 221A and the second electrode portion 221B are each formed into a rectangular shape by repeatedly bending or curving the conductive linear body 22 through 180° in a plan view. The portions of the conductive linear body 22 that are formed in a wave-like shape in a plan view are the first wiring portion 222A and the second wiring portion 222B. In one aspect, the first electrode portion 221A and the second electrode portion 221B and the first wiring portion 222A and the second wiring portion 222B are fastened by fibers or the like (not shown) that constitute the stretchable member 21.

[0021] 3A, in the stretch sensor 2, the first wiring portion 222A and the second wiring portion 222B are arranged to be in point contact or line contact with each other. As shown in FIG. 3B, the first electrode portion 221A and the second electrode portion 221B are stretched in directions away from each other, and when the stretch rate exceeds a certain level, the first wiring portion 222A and the second wiring portion 222B are separated from each other. When the first wiring portion 222A and the second wiring portion 222B are separated from each other, electrical continuity is lost between the first wiring portion 222A and the second wiring portion 222B, and when the resistance value between the first electrode portion 221A and the second electrode portion 221B is measured, the measured value changes. On the other hand, when the stretching of the first electrode portion 221A and the second electrode portion 221B in the direction away from each other is released and the stretching rate falls below a certain level, the first wiring portion 222A and the second wiring portion 222B again come into point or line contact with each other, thereby establishing electrical continuity between the first wiring portion 222A and the second wiring portion 222B. When such an expansion sensor 2 is used, the expansion sensor 2 has the function of detecting contact with an obstacle by detecting a change in the resistance value between the first electrode portion 221A and the second electrode portion 221B.

[0022] The expansion sensor 2 used in this embodiment is energized (ON) when not in contact (when not extended) and is de-energized (OFF) when in contact (when extended), so if there is an abnormality in the expansion sensor 2, that abnormality can be detected when not in contact. In other words, most general sensors have a mechanism that turns off when not in contact, and such sensors cannot detect a malfunction in advance if the sensor itself is malfunctioning. In contrast, the expansion sensor 2 used in this embodiment is on when not in contact, so a malfunction in the expansion sensor 2 can be detected.

[0023] Here, when the expandable sensor 2 detects contact with an obstacle, the detection depth of the expandable sensor 2 is preferably 5 mm or more and 40 mm or less, and more preferably 10 mm or more and 35 mm or less. If the detection depth is above the lower limit, the sensor will react even with slight contact with the surface, making it difficult to operate. On the other hand, if the detection depth is below the upper limit, a force is required to push in the flexible member 3, and the reaction sensitivity is less likely to decrease.

[0024] Furthermore, in order to achieve the optimal detection depth of the stretchable sensor 2, it is preferable that the extension rate of the stretchable member 21 and the length of the stretchable sensor 2 are as follows. Note that these values ​​can be adjusted as appropriate depending on the shape or size of the contact sensor. When the stretchable sensor 2 detects contact with an obstacle, it is preferable that the extension rate of the stretchable member 21 be 10% or more and 50% or less, and more preferably 20% or more and 40% or less. If this extension rate is equal to or greater than the lower limit, the stretchability of the stretchable sensor 2 can be ensured, while if it is equal to or less than the upper limit, reaction sensitivity can be ensured.

[0025] Furthermore, when the stretchable sensor 2 detects contact with an obstacle, the length of the stretchable sensor 2 is preferably 20 mm or more and 1000 mm or less, more preferably 50 mm or more and 500 mm or less, and particularly preferably 80 mm or more and 300 mm or less. If the length of the stretchable sensor 2 is equal to or greater than the lower limit, a sufficient detection area of ​​the stretchable sensor 2 can be ensured, while if the length is equal to or less than the upper limit, the detection depth can be made shallower, thereby ensuring reaction sensitivity. Note that the length of the stretchable sensor 2 refers to the distance between the ends of the stretchable sensor 2 in the direction in which the first electrode portion 221A and the second electrode portion 221B are spaced apart in a plan view.

[0026] The elastic member 21 may be any material as long as it has elasticity, and is not particularly limited. However, from the viewpoint of elasticity and shock absorption, it is preferably a fabric material. The fabric material may be any of woven fabric, knitted fabric, and nonwoven fabric. The fibers constituting the fabric material are preferably insulating fibers. Here, the concept of fibers constituting the fabric material includes threads. Furthermore, insulating fibers are fibers having a linear resistance of 1.0×10 ６ This indicates a thread with a resistance of Ω / cm or more. The linear resistance is determined by applying silver paste to both ends of the fabric material, measuring the resistance between the silver pastes, and determining the resistance value (unit: Ω) of the fabric material. The linear resistance can then be calculated by dividing the obtained resistance value by the distance (cm) between the silver pastes. The fibers constituting the fabric material may be either natural fibers or synthetic fibers, or a mixture of these. The fabric material may have a single-layer structure or a multi-layer structure of two or more layers.

[0027] The conductive linear body 22 is not particularly limited as long as it is conductive. The conductive linear body 22 may be, for example, a linear body including a metal wire, a linear body including a conductive thread, or a twisted thread thereof. The metal wire may be a linear body consisting of a single metal wire or a linear body including multiple twisted metal wires. Examples of metal wires include wires containing a single metal such as copper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver, and gold, or an alloy containing two or more metals. Examples of metal wires include metal wires coated with metal plating or a carbon material. Examples of linear bodies containing conductive threads include linear bodies containing conductive fibers, linear bodies containing conductive particles, linear bodies with metal plating or vapor deposition on their surfaces, and linear bodies containing carbon nanotubes. Among these, from the viewpoint of durability, etc., the conductive linear body 22 is preferably a linear body containing carbon nanotubes. It is more preferable that the linear body containing carbon nanotubes is a linear body containing carbon nanotube threads.

[0028] (Flexible Member) In the contact detection sensor 100 according to this embodiment, as shown in FIGS. 1 and 2 , the sensor unit 1 preferably further includes a flexible member 3 that deforms under pressure and absorbs impact. In this case, the stretch sensor 2 is preferably provided closer to the contact surface 1A of the sensor unit 1 than the flexible member 3. With this configuration, when the contact detection sensor 100 comes into contact with an obstacle, the flexible member 3 can absorb the impact. Furthermore, because the stretch sensor 2 is provided closer to the contact surface 1A of the sensor unit 1 than the flexible member 3, there is no decrease in response sensitivity. While conventional contact detection sensors require adjustment of the material of the flexible member to achieve both impact absorption and response sensitivity, this is not necessary in the contact detection sensor 100 according to this embodiment. In other words, arranging the stretch sensor 2 on the front surface of the flexible member 3 advantageously increases the flexibility of the flexible member 3.

[0029] The flexible member 3 is not particularly limited as long as it has flexibility. However, from the viewpoint of flexibility and durability, a sponge-like member is preferable. The material of the flexible member 3 is not particularly limited, but is preferably a resin. Examples of resins include polyurethane, polyester, and melamine resin. Among these, polyurethane is preferable. The thickness of the flexible member 3 is not particularly limited, but is preferably 1 mm or more and 100 mm or less, more preferably 5 mm or more and 80 mm or less, and particularly preferably 10 mm or more and 50 mm or less. If the thickness of the flexible member 3 is equal to or greater than the lower limit, the flexibility of the flexible member 3 can be ensured. On the other hand, if the thickness is equal to or less than the upper limit, the durability of the flexible member 3 can be ensured.

[0030] 1 and 2 , in the contact detection sensor 100 according to this embodiment, it is preferable that the sensor unit 1 further includes a skin material 4 provided on the surface side of the contact detection sensor 100, i.e., closer to the contact surface 1A of the sensor unit 1 than the stretch sensor 2. With this configuration, it is possible to protect the surface of the stretch sensor 2 and improve the durability of the stretch sensor 2.

[0031] The covering material 4 may be any material capable of protecting the surface of the stretch sensor 2, and is not particularly limited. However, from the viewpoints of stretchability and durability, a resin film, rubber material, or cloth material is preferable. Examples of resin films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, ionomer resin film, ethylene-(meth)acrylic acid copolymer film, ethylene-(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate film, and polyimide film. Examples of rubber materials include natural rubber, styrene-butadiene rubber, chloroprene rubber, acrylonitrile rubber, butyl rubber, ethylene-propylene rubber, urethane rubber, silicone rubber, fluororubber, and chlorosulfonated polyethylene rubber. Examples of cloth materials are the same as those used for the stretchable member 21.

[0032] (Physical Properties of Contact Detection Sensor) When the contact detection sensor 100 according to this embodiment is subjected to a repeated expansion and contraction test described in the examples below, the number of repetitions is preferably 100,000 or more. The greater the number of repetitions, the better the durability of the contact detection sensor 100. Furthermore, if the number of repetitions is 100,000 or more, the durability of the contact detection sensor 100 can be said to be sufficient.

[0033] (Effects of the Embodiment) This embodiment can achieve the following effects. (1) According to this embodiment, the stretch sensor 2 can absorb impacts by expanding and contracting, even when it receives a direct impact. Therefore, there is no need to provide a cushioning material on the surface of the stretch sensor 2. This eliminates the need for a cushioning material on the surface of the stretch sensor 2. This increases the response sensitivity compared to conventional methods. (2) According to this embodiment, the stretch sensor 2 is soft, so there is no problem of pain when a person bumps into the sensor unit 1. (3) According to this embodiment, the stretch sensor 2 is conductive when not in contact and non-conductive when in contact. Therefore, if there is an abnormality in the stretch sensor 2, the abnormality can be detected even when not in contact. (4) According to this embodiment, the flexible member 3 can absorb impacts when the contact detection sensor 100 comes into contact with an obstacle. Furthermore, because the stretch sensor 2 is located closer to the contact surface 1A of the sensor unit 1 than the flexible member 3, there is no decrease in response sensitivity. (5) According to this embodiment, the skin material 4 located closer to the contact surface 1A of the sensor unit 1 than the stretch sensor 2 can protect the surface of the stretch sensor 2, thereby improving the durability of the stretch sensor 2.

[0034] [Modifications of the Embodiments] The present invention is not limited to the above-described embodiments, and includes modifications or improvements within the scope of achieving the object of the present invention. For example, the above-described embodiment uses the stretch sensor 2 shown in FIG. 3A, but is not limited to this. For example, a known stretch sensor of another form may be used as the stretch sensor 2.

[0035] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples. The contact detection sensors obtained in the examples were evaluated as follows.

[0036] [Contact Detection Evaluation] The contact detection sensor was fixed to a measuring device, and wiring was attached to each of the two electrodes of the expansion sensor of the contact detection sensor, allowing measurement of the resistance between the electrodes. A cylindrical test rod with a diameter of 35 mm was then pressed against the expansion sensor of the contact detection sensor, and a load was applied to measure the resistance between the electrodes while the rod was being pressed. When the resistance between the electrodes increased to 100 times or more the initial resistance, contact detection was judged to have occurred, and the contact detection was evaluated as "A." The depth of the pressurization at this point was measured as the detection depth. On the other hand, when the resistance was less than 100 times the initial resistance, the contact detection was evaluated as "F."

[0037] [Durability Evaluation of Stretch Sensor] A repeated stretching test was conducted on the stretch sensor under the following test conditions. A contact detection sensor was produced using the stretch sensor after this repeated stretching test, and the contact detection evaluation was conducted on the resulting contact detection sensor. If it was determined that contact detection had occurred, the durability was rated as "A", and otherwise the durability was rated as "F". Furthermore, with regard to the contact detection of the stretch sensor before and after the repeated stretching test, if contact detection was detected it was rated as "A", and if no contact detection was detected it was rated as "F". (Test Conditions) Measurement length: 20 mm Stretch range: 0% to 60% (20 mm to 32 mm) Repetition interval: 1 Hz Number of repetitions: 100,000 times

[0038] Example 1 A stretch sensor as shown in FIG. 3A was fabricated using an insulating and stretchable polyester-polyurethane blend yarn and a conductive linear carbon nanotube yarn manufactured by Lintec Corporation. The length of the stretch sensor was 100 mm. The sensor reaction elongation rate (stretch range in durability evaluation of the stretch sensor) was 20%. The resulting stretch sensor was attached to flexible member A (sponge manufactured by Konan Shoji Co., Ltd., material: polyurethane, thickness: 55 mm) to fabricate a contact detection sensor. The resulting contact detection sensor was evaluated for contact detection and durability. The results are shown in Tables 1 and 2.

[0039] [Examples 2 to 9 and Comparative Example 1] Contact detection sensors were produced in the same manner as in Example 1, except that the manufacturing conditions for the stretchable sensor were changed as shown in Table 1. The materials used in each example are as follows: Flexible member B (sponge manufactured by WAKI Sangyo Co., Ltd., material: ether-based urethane foam, thickness: 30 mm) Cover material (polyester nonwoven fabric, thickness: 0.2 mm) The obtained contact detection sensors were subjected to a contact detection evaluation in the same manner as in Example 1. The obtained results are shown in Table 1.

[0040]

[0041]

[0042] As is clear from the results shown in Tables 1 and 2, the contact detection sensors obtained in Examples 1 to 9 were confirmed to have detection depths within an appropriate range and to have excellent durability as expansion sensors. Therefore, it was confirmed that the present invention can provide a contact detection sensor with high response sensitivity.

[0043] 1...sensor portion, 2...stretchable sensor, 21...stretchable member, 22...conductive linear body, 221A...first electrode portion, 221B...second electrode portion, 222A...first wiring portion, 222B...second wiring portion, 3...flexible member, 4...cover material, 5...wiring, 100...contact detection sensor

Claims

1. A contact detection sensor having a sensor unit that detects contact while absorbing impact at the time of contact, the sensor unit having an expansion and contraction sensor.

2. A contact detection sensor as claimed in claim 1, wherein the sensor section further comprises a flexible member which deforms in response to pressure to absorb shock, and the stretch sensor is provided on the contact surface side of the sensor section relative to the flexible member.

3. A contact detection sensor according to claim 1 or 2, wherein the sensor section further comprises a skin material provided on the surface side of the stretch sensor.

4. A contact detection sensor according to claim 1 or 2, the stretch sensor comprising: an elastic member having stretchability; an electrode portion including a conductive linear body; and a wiring portion electrically connected to the electrode portion and including a conductive linear body.

5. A contact detection sensor as described in claim 4, wherein the stretch sensor comprises two electrode portions, a first electrode portion and a second electrode portion, and two wiring portions, a first wiring portion and a second wiring portion, the stretchable member is a cloth material, and when the resistance value between the first electrode portion and the second electrode portion is measured while the cloth material is stretched, the measured value changes.

6. A contact detection sensor according to claim 4, wherein the conductive linear body is a linear body including a carbon nanotube.

7. A contact detection sensor as claimed in claim 4, wherein, when said stretch sensor detects contact, the stretch rate of said stretchable member is 10% or more and 50% or less.

8. A contact detection sensor according to claim 1 or 2, wherein, when the expansion sensor detects contact, the detection depth of the expansion sensor is 5 mm or more and 40 mm or less.

9. A contact detection sensor according to claim 1 or 2, wherein the stretch sensor is in a conducting state when not in contact and in a non-conducting state when in contact.

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