WO2018179911A1

WO2018179911A1 - Force sensor

Info

Publication number: WO2018179911A1
Application number: PCT/JP2018/004682
Authority: WO
Inventors: 佐藤　邦生; 高井　大輔; 和人大下; 元志方; 俊季中村
Original assignee: アルプス電気株式会社
Priority date: 2017-03-25
Filing date: 2018-02-09
Publication date: 2018-10-04
Also published as: JP2020091097A

Abstract

[Problem] To provide a force sensor that is able to detect conditions such as direction, magnitude, range, and distribution of a load having been applied. [Solution] The present invention is provided with: a base material; a plurality of pressure sensitive members that are fixed so as to be apart from each other at a predetermined interval on the base material and that perform predetermined output in accordance with an applied load; and an operation member that has a contact area in contact with the plurality of pressure sensitive members, wherein a load is applied to the plurality of pressure sensitive members in accordance with an operation on the operation member. In addition, a calculation unit that detects conditions of the load applied to the operation member on the basis of output information from the plurality of pressure sensitive members is provided.

Description

Force sensor

The present invention relates to a force sensor capable of detecting a load applied by an operation on an operation member.

For example, the load detection device described in Patent Document 1 is disposed on the upper surface side of the load sensor, a load sensor having a protruding pressure receiving portion, a case for storing the load sensor with the pressure receiving portion facing the upper surface side, and a load. And an elastic body that receives and presses the load sensor in the height direction. Thereby, it is said that it is possible to provide a load detection device that can realize good handling properties and miniaturization and has good sensor sensitivity.

Japanese Patent Laying-Open No. 2015-161531

However, in the load detection device described in Patent Document 1, although the pressing force in the height direction can be detected by the load sensor, the situation such as the direction, range, and distribution of the load applied to the elastic body is detected. I couldn't. Therefore, even if this load detection device is incorporated in a remotely operated structure, for example, the state of the load applied to this structure is not clear, and the touch transmission performed based on this detection result lacks detail. It was difficult to reproduce the realistic feel.

Therefore, an object of the present invention is to provide a force sensor that can detect the direction, magnitude, range, distribution, and the like of an applied load.

In order to solve the above problems, a force sensor according to an embodiment of the present invention is fixed on a base material and the base material at predetermined intervals, and outputs a predetermined output according to an applied load. A plurality of pressure-sensitive members to be performed and an operation member having a contact area in contact with the plurality of pressure-sensitive members are provided, and a load is applied to the plurality of pressure-sensitive members according to an operation on the operation member.

In this case, the state of the load applied to the operation member can be detected.

The force sensor according to the embodiment of the present invention may include a calculation unit that detects a state of a load applied to the operation member based on output information from a plurality of pressure-sensitive members.

In this case, it is possible to accurately calculate the situation such as the direction, size, range and distribution of the load applied to the operation member.

In the force sensor according to the embodiment of the present invention, each of the plurality of pressure-sensitive members may include a plurality of strain detection elements.

In this case, since the magnitude of distortion generated in a plurality of directions can be detected for each pressure-sensitive member, it is possible to accurately calculate the state of the load applied to the operation member.

In the force sensor according to the embodiment of the present invention, in each of the plurality of pressure-sensitive members, the plurality of strain detection elements may be arranged symmetrically with respect to the plane center of the pressure-sensitive member.

In this case, since the distortion generated in each pressure-sensitive member can be detected with high accuracy, the detection accuracy as a force sensor can be increased.

In the force sensor according to one embodiment of the present invention, four pressure-sensitive members are arranged so as to be symmetric with respect to the plane center of the base material, and each pressure-sensitive member is symmetric with respect to the plane center. Four strain sensing elements may be provided.

In this case, since the distribution of strain on the plane coordinates of the base material can be calculated in each pressure-sensitive member, the load applied to the operation member can be accurately calculated based on these.

In the force sensor in one embodiment of the present invention, the operation member may be attached to the base material so as to cover the plurality of pressure sensitive members.

In this case, since the load applied by the operation on the operation member can be detected by a plurality of pressure-sensitive members, the state of the load applied in a complicated manner can be detected.

In the force sensor according to the embodiment of the present invention, the operation member may have elasticity.

In this case, it is possible to accurately detect the state of the applied load while giving a realistic feel to the operator.

According to one embodiment of the present invention, it is possible to provide a force sensor that can detect the state of the direction, magnitude, range, distribution, etc. of the load applied to the operation member.

It is a side view which shows the structure of the force sensor which concerns on embodiment of this invention. It is a top view which shows the structure of the force sensor which concerns on embodiment of this invention. It is a functional block diagram of a force sensor concerning an embodiment of the present invention. It is a figure which shows the example of application of a force sensor. It is a figure which shows the example of application of a force sensor. It is a perspective view which shows the structure of the 1st pressure sensitive member in embodiment of this invention. It is a circuit diagram of the distortion detection element with which the 1st pressure sensitive member in the embodiment of the present invention is provided. It is a top view which shows the structure of the four pressure sensitive members in embodiment of this invention. It is a figure which shows the direction of the external force applied to the force sensor. It is a figure which shows the direction of the external force applied to the force sensor. It is a figure which shows the direction of the external force applied to the force sensor. It is a figure which shows the direction of the external force applied to the force sensor. It is a figure which shows the direction of the external force applied to the force sensor. It is a top view which shows the structure of the four pressure sensitive members in the 1st modification of embodiment. It is a top view which shows the structure of the four pressure sensitive members in the 1st modification of embodiment. It is a circuit diagram of the distortion detection element with which the 1st pressure sensitive member in the 2nd modification of an embodiment is provided.

Hereinafter, a force sensor according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view showing the configuration of the force sensor 10 according to the present embodiment, FIG. 2 is a plan view showing the configuration of the force sensor 10, and FIG. 3 is a functional block diagram of the force sensor 10. 4A and 4B are diagrams showing application examples of the force sensor 10. The operation member 12 is virtually shown by a broken line in FIG. 1 and omitted in FIG. In each figure, XYZ coordinates are shown as reference coordinates. The Z direction is the upward direction, and the XY plane is a plane orthogonal to the Z direction. In the following description, the state viewed along the Z direction may be referred to as a plan view.

As shown in FIG. 1 or 2, the force sensor 10 according to the present embodiment includes a base material 11, four pressure-

sensitive members

20, 30, 40, 50 arranged on the base material 11, and these The operation member 12 is mounted on the base material 11 so as to cover the pressure sensitive member. In the present embodiment, four examples of the pressure sensitive member are shown, but the number of pressure sensitive members is two, three. The number and arrangement may be arbitrarily set according to the specifications of the force sensor.

The base material 11 is, for example, a circuit board, and an integrated circuit constituting the calculation unit 61 and the control unit 62 shown in FIG. 3 and wirings connected to the integrated circuit are arranged. The control unit 62 has an interface unit. For example, the control unit 62 gives the calculation result of the calculation unit 61 to the external display device 63 for display.

The operation member 12 is made of an elastic material, for example, synthetic rubber such as urethane rubber or silicone rubber, and the upper portions of the

operation bodies

25, 35, 45, 55 of the four pressure-

sensitive members

20, 30, 40, 50. Are arranged so as to cover from above the Z direction, and preferably the end portion 12a in the XY plane direction is fixed to the base material 11 by adhesion. The operation member 12 has an inner surface 12b, the operation body 25 of the first pressure-sensitive member 20, the operation body 35 of the second pressure-sensitive member 30, the operation body 45 of the third pressure-sensitive member 40, and the fourth sensitivity. A contact region that contacts the operating body 55 of the pressure member 50 is configured.

The operation member 12 constitutes an epidermis F1 of a finger F of a human body model as shown in FIG. 4A, for example. In this configuration, the base material 11 and the four pressure-

sensitive members

20, 30, 40, 50 fixed on the base material 11 are arranged inside the finger F.

Further, instead of the operation member 12 shown in FIG. 1, an operation member 112 having the configuration shown in FIG. 4B can be used. The operation member 112 includes an operation main body 112a and an arm portion 112b extending downward from the operation main body 112a, and both the operation main body 112a and the arm portion 112b are made of a hard material, for example, metal. On the other hand, two pressure-

sensitive members

120 and 130 are disposed on the substrate 111, and between the operating body 125 of the first pressure-sensitive member 120 and the operating body 135 of the second pressure-sensitive member 130. The arm portion 112b of the operation member 112 is disposed. Here, the base 111 and the two pressure-

sensitive members

120 and 130 have the same configuration as the base 11 and the four pressure-sensitive members 20 to 50 shown in FIG. 2, respectively. In the operation member 112, the side surface 112 c of the arm portion 112 b constitutes a contact area in contact with the

operation bodies

125 and 135 of the two pressure

sensitive members

120 and 130. In such a configuration, when an external force is applied to the operation main body 112a, the arm portion 112b is inclined with respect to the Z direction together with the operation main body 112a, and accordingly, the

operation bodies

125 and 135 are inclined.

As shown in FIG. 2, each of the four pressure-

sensitive members

20, 30, 40, 50 has

support bases

22, 32, 42, 52 each having a square outer shape in plan view, and the outer edges thereof are bonded to each other by bonding. It is fixed to the material 11. The four pressure-

sensitive members

20, 30, 40, 50 are arranged symmetrically with respect to the center 11 c of the plane of the base material 11 at regular intervals. More specifically, the first pressure-sensitive member 20 and the second pressure-sensitive member 30, the second pressure-sensitive member 30 and the third pressure-sensitive member 40, the third pressure-sensitive member 40 and the fourth pressure-sensitive member. The pressure member 50 and the fourth pressure-sensitive member 50 and the first pressure-sensitive member 20 are arranged on the base material 11 so as to be separated from each other with a distance L in both the X direction and the Y direction. Has been. Further, in the Y direction, the first pressure sensitive member 20 and the third pressure sensitive member 40 are disposed so as to have a distance of 2L, and in the X direction, the second pressure sensitive member 30 and the fourth pressure sensitive member. 50 is also arranged at a distance of 2L.

Here, the distance L can be arbitrarily set according to the application and specifications.

The configuration of the pressure-sensitive member will be described with reference to FIGS. FIG. 5 is a perspective view showing a configuration of the first pressure-sensitive member 20, and FIG. 6 is a circuit diagram of a strain detection element included in the first pressure-sensitive member 20. FIG. 7 is a plan view showing the configuration of the four pressure-

sensitive members

20, 30, 40, 50.

Here, since the four pressure-

sensitive members

20, 30, 40, and 50 have the same configuration, only the first pressure-sensitive member 20 will be described, and the detailed description of the other pressure-

sensitive members

30, 40, and 50 will be described. Is omitted.

The first pressure-sensitive member 20 has a support base 22 made of synthetic resin. The support base 22 is integrally formed with a plus X deforming portion 23a and a minus X deforming portion 23b extending in the X direction and a plus Y deforming portion 24a and a minus Y deforming portion 24b extending in the Y direction. An operation body 25 that protrudes concentrically upward is integrally provided at the center of the plane of the support base 22. The operating body 25 is disposed at the center of the plus X deforming portion 23a and the minus X deforming portion 23b and the center of the plus Y deforming portion 24a and the minus Y deforming portion 24b.

When a load corresponding to the operating force is applied to the operating body 25 that is in contact with the inner surface 12b of the operating member 12 when the operating member 12 is operated with a finger or the like, the operating direction and the operating force correspond to the operating direction. The plus X deforming portion 23a, the minus X deforming portion 23b, the plus Y deforming portion 24a, and the minus Y deforming portion 24b are bent.

As shown in FIG. 5, in the support base 22, a plus X strain sensor 26a is attached to the upper surface of the plus X deformation portion 23a, and a minus X strain sensor 26b is attached to the upper surface of the minus X deformation portion 23b. . Further, a plus Y strain sensor 27a is attached to the upper surface of the plus Y deformation portion 24a, and a minus Y strain sensor 27b is attached to the upper surface of the minus Y deformation portion 24b. These

strain sensors

26 a, 26 b, 27 a, 27 b are arranged symmetrically with respect to the operating body 25 located at the plane center of the support base 22.

Note that the

strain sensors

26a, 26b, 27a, and 27b may be attached to the lower surfaces of the

deformable portions

23a, 23b, 24a, and 24b, respectively.

The

strain sensors

26a, 26b, 27a, and 27b are strain detection elements that detect strain and deflection generated in the

deformed portions

23a, 23b, 24a, and 24b, respectively, and are formed as resistance films. As shown in FIG. 6, the

strain sensors

26a, 26b, 27a, and 27b are connected to each other to form a bridge circuit.

When the operating body 25 is pressed so as to fall in the θx direction or the θy direction shown in FIG. 5 or other directions, the plus X deforming portion 23a and the minus X deforming are made according to the pressing direction and the pressing force. Deflection occurs in the portion 23b, the plus Y deformation portion 24a, and the minus Y deformation portion 24b, and the resistance values of the

respective strain sensors

26a, 26b, 27a, and 27b change. Further, even when the operating body 25 is pressed downward, the

deformation portions

23a, 23b, 24a, and 24b are deflected according to the pressing force, and the

distortion sensors

26a, 26b, 27a, and 27b are deformed. The resistance value changes. In accordance with such a change in resistance value, an X operation output and a Y operation output are obtained from the bridge circuit shown in FIG.

The X operation output and the Y operation output obtained in response to changes in the resistance values of the

strain sensors

26 a, 26 b, 27 a, 27 b of the first pressure-sensitive member 20 are given to the calculation unit 61. Similarly, an X operation output and a Y operation output corresponding to a change in the resistance value of the strain sensor in each of the pressure

sensitive members

30, 40, 50 are also given to the calculation unit 61. The calculation unit 61 detects the state of the load applied to the operation member 12 based on output information given from the four pressure

sensitive members

20, 30, 40, 50.

Here, as shown in FIG. 7, the support base 32 of the second pressure-sensitive member 30 has a plus X strain sensor 26a, a minus X strain sensor 26b, and a plus Y strain sensor 27a in the first pressure sensitive member 20. Similarly to the minus Y distortion sensor 27b, a plus X distortion sensor 36a, a minus X distortion sensor 36b, a plus Y distortion sensor 37a, and a minus Y distortion sensor 37b are attached. Similarly, a plus X strain sensor 46a, a minus X strain sensor 46b, a plus Y strain sensor 47a, and a minus Y strain sensor 47b are attached to the support base 42 of the third pressure-sensitive member 40. A plus X strain sensor 56a, a minus X strain sensor 56b, a plus Y strain sensor 57a, and a minus Y strain sensor 57b are attached to the support base 52 of the pressure sensitive member 50.

The force sensor 10 having the above-described configuration can detect the situation such as the direction, size, range, and distribution of the load applied by an external force as shown in FIGS. 8A to 8E, for example. 8A to 8E are side views corresponding to FIG. 1, showing the direction of the external force applied to the force sensor 10, and the illustration of the operation member 12 is omitted. FIG. 8A to FIG. 8E show some examples, and it is possible to detect other loads, for example, the situation of the load due to the combined force of the external forces shown in FIG. 8A to FIG. 8E. 8A to 8E, it is assumed that the force sensor 10 is mounted so that the Z direction is along the vertical direction. However, the mounting direction of the force sensor 10 is not limited to this. It is not limited.

First, as shown in FIG. 8A, when the operation member 12 is pushed downward from the upper direction, a downward force D1 acts on all of the four pressure-

sensitive members

20, 30, 40, and 50, and each has a distortion. A change occurs in the resistance value in the sensor. Further, when an operation is performed to squeeze the operation member 12 from the upper direction and the left direction, in addition to the force D1, a force D2 along the X direction acts as a horizontal force. In this case, due to the force D2, changes in resistance values of the plus X strain sensors and minus X strain sensors of the four pressure-

sensitive members

20, 30, 40, and 50 are superimposed.
Thus, based on the change of the resistance value generated in each strain sensor, the calculation unit 61 can detect the situation such as the direction, magnitude, range, and distribution of the load applied to the operation member 12.

In FIG. 8B, two forces D3 and D4 along the positive direction and the negative direction in the X direction are shown as forces from both the left and right directions. As a case where such an external force is applied, an operation of pinching the operation member 12 from the left-right direction is assumed. When such an operation that simultaneously applies the forces D3 and D4 is performed, the resistance values of all of the four pressure-

sensitive members

20, 30, 40, and 50 plus and minus X strain sensors change. Based on the change in resistance value generated in each strain sensor, the calculation unit 61 can detect the state of the direction, magnitude, range, distribution, etc. of the load applied to the operation member 12.

In FIG. 8C, two forces D5 and D6 along the negative direction and the positive direction in the X direction are shown as forces along the left and right directions. As a case where such an external force is applied, an operation of expanding the operation member 12 in the left-right direction is assumed. When such an operation that simultaneously applies the forces D5 and D6 is performed, the resistance values of all of the four pressure-

sensitive members

FIG. 8D shows a force D7 that rotates in a plane parallel to the XY plane. As a case where such an external force is applied, an operation of twisting the operation member 12 about the vertical axis is assumed. Alternatively, an operation is assumed in which a rotational force is applied to the operation member 12 so that a pressing force is applied to the pressure-

sensitive members

20, 30, 40, and 50 in order. When such an operation to apply the force D7 is performed, the resistance values change in order in all the strain sensors of the four pressure-

sensitive members

20, 30, 40, and 50. Thus, based on the change of the resistance value generated in each strain sensor, the calculation unit 61 can detect the situation such as the direction, magnitude, range, and distribution of the load applied to the operation member 12.

FIG. 8E shows forces D8, D9, and D10 in different directions. As a case where such an external force is applied, an operation of pushing the operation member 12 while twisting, an operation of giving different movements by a plurality of fingers, and the like are assumed. When such an operation in which the forces D8 to D10 are simultaneously applied is performed, the resistance value is changed in all the strain sensors of the four pressure-

sensitive members

Since it is configured as described above, according to the above-described embodiment, it is possible to accurately detect the state, such as the direction, size, range, and distribution of the load applied to the operation member 12.

Further, four pressure-

sensitive members

20, 30, 40, 50 are arranged so as to be symmetric with respect to the plane center 11c of the base material 11, and each of the pressure-sensitive members has four strains so as to be symmetric with respect to the plane center. A sensing element is provided. For this reason, in each pressure-sensitive member, since the distribution of the distortion on the plane coordinate of the base material 11 can be calculated, the load applied to the operation member 12 can be accurately calculated based on these.

Since the operation member 12 is mounted on the base material 11 so as to cover the four pressure-

sensitive members

20, 30, 40, 50, the load applied by the operation on the operation member 12 can be detected by the four pressure-sensitive members. Therefore, it is possible to detect the condition of the load applied in a complicated manner.

The operation member 12 has elasticity, so that it is possible to accurately detect the state of the applied load while giving a realistic feel to the operator.

Hereinafter, modifications of the above embodiment will be described.

9 and 10 are plan views showing the configuration of the four pressure-sensitive members in the first modification of the above embodiment. In the above embodiment, each pressure-sensitive member has a pair of strain sensors arranged in the X direction and the Y direction, but a pair of strain sensors is disposed only in one direction, and the strain sensor in the other direction. May be omitted. For example, as shown in FIG. 9, a pair of strain sensors may be arranged on each pressure-sensitive member so as to surround the planar center 11 c of the base material 11. Further, as shown in FIG. 10, a pair of strain sensors may be arranged on each pressure-sensitive member along the direction toward the planar center 11 c of the base material 11. With such a configuration, it is possible to detect the state of the load applied to the operation member 12 with a few strain sensors.

FIG. 11 is a circuit diagram of a strain detection element provided in the first pressure-sensitive member in the second modification of the embodiment. In the above embodiment, the X operation output and the Y operation output are obtained from the bridge circuit shown in FIG. 6, but in addition to this, a Z operation output can also be obtained, whereby a load along the Z direction can be obtained. It is possible to detect a more detailed situation including

In the example shown in FIG. 11, four

strain sensors

26a, 26b, 27a, and 27b are connected to each other to form a bridge circuit as in FIG. 6, and a combined resistor 29 is formed as the entire bridge circuit. A changeover switch SW for switching to one of two states S1 and S2 is provided between the combined resistor 29 and the Vcc power supply. When the changeover switch SW is in the state S1, the Vcc power supply and the combined resistor 29 are directly connected. When the changeover switch SW is in the state S2 by switching, the Vcc power supply and the combined resistor 29 are connected via the fixed resistor 28. The changeover switch SW and the fixed resistor 28 are provided on the substrate 11, and a Z operation output is obtained from between the fixed resistor 28 and the combined resistor 29. The changeover switch SW is controlled by the control unit 62, and the two states S1 and S2 are switched at regular intervals. Or you may switch by operation of an operator.

In the second modification, for example, when the operating body 25 is pushed down along the Z direction, the four

strain sensors

26a, 26b, 27a, and 27b extend (or contract) in the same manner, so that the combined resistance 29 is large. Become. Therefore, in the state S2, a change occurs in the Z operation output taken out between the fixed resistor 28 and the combined resistor 29. Based on this output information, the state in the Z direction applied to the operation member 12 is calculated in the calculation unit 61. Detected. On the other hand, the X operation output and the Y operation output are obtained during the period of the state S1. By sequentially switching between the two states S1 and S2 and obtaining the Z operation output, the X operation output, and the Y operation output, it is possible to capture the state of the load applied to the operation member 12 in three dimensions.

In actual measurement, when two states S1 and S2 are repeated at a predetermined cycle and the state S1 is set, the operation unit 61 monitors the X operation output and the Y output, and the state S2 is set. Further, the Z operation output is monitored by the calculation unit 61.

Or, depending on the usage, it may be used while being fixed in the state S1, or may be used while being fixed in the state S2.

Although the present invention has been described with reference to the above-described embodiments and modifications, the present invention is not limited to the above-described embodiments and modifications, and improvements or modifications can be made within the scope of the purpose of the improvement or the idea of the present invention. Is possible.

As described above, the force sensor according to the embodiment of the present invention is useful in that it can detect the situation such as the direction, magnitude, range, distribution, and the like of the load applied to the operation member.

This application is based on Japanese Patent Application No. 2017-060241 filed with the Japan Patent Office on March 25, 2017, claims priority, and refers to the entire contents of that application. It is included.

DESCRIPTION OF SYMBOLS 10 Force sensor 11 Base material 11c Plane center 12 Operation member 12b Inner surface (contact area)
20 First pressure-

sensitive member

22, 32, 42, 52 Support base 23a Plus X deformed portion 23b Minus X deformed portion 24a Plus Y deformed portion 24b Minus Y

deformed portion

25, 35, 45, 55

Operating body

26a, 36a, 46a 56a Plus

X strain sensor

26b, 36b, 46b, 56b Minus

X strain sensor

27a, 37a, 47a, 57a Plus

Y strain sensor

27b, 37b, 47b, 57b Minus Y strain sensor 30 Second pressure sensitive member 40 Third Pressure sensing member 50 Fourth pressure sensing member 61 Calculation unit 62 Control unit 63 Display device 111 Substrate 112 Operation member 112a Operation body 112b Arm portion 112c Side surface 120 First

pressure sensing member

125, 135 Operation body 130 Second sense Pressure member

Claims

A substrate;
A plurality of pressure-sensitive members that are fixed at a predetermined interval on the base material and that perform a predetermined output according to an applied load;
An operation member having a contact region that contacts the plurality of pressure sensitive members,
The force sensor, wherein the load is applied to the plurality of pressure-sensitive members in accordance with an operation on the operation member.
The force sensor according to claim 1, further comprising a calculation unit that detects a state of a load applied to the operation member based on output information from the plurality of pressure-sensitive members.
The force sensor according to claim 2, wherein each of the plurality of pressure-sensitive members includes a plurality of strain detection elements.
The force sensor according to claim 3, wherein in each of the plurality of pressure-sensitive members, the plurality of strain detection elements are arranged symmetrically with respect to a planar center of the pressure-sensitive member.
The plurality of pressure-sensitive members are arranged so as to be symmetric with respect to the plane center of the base material, and each of the pressure-sensitive members has four strain sensing elements arranged so as to be symmetric with respect to the plane center. The force sensor according to any one of claims 1 to 4, further comprising:
The force sensor according to any one of claims 1 to 5, wherein the operation member is attached to the base so as to cover the plurality of pressure-sensitive members.
The force sensor according to claim 6, wherein the operation member has elasticity.