JP5678669B2 - Ultrasonic sensor, tactile sensor, and gripping device - Google Patents

Description

  The present invention relates to an ultrasonic sensor that transmits ultrasonic waves, a tactile sensor that detects contact of a contact object with ultrasonic waves transmitted from the ultrasonic sensor, and a gripping device including the tactile sensor.

  2. Description of the Related Art Conventionally, a sensor that detects a stress that is applied by contact with an object when an object with an unknown weight or friction coefficient is gripped by a robot arm or the like is known (for example, see Patent Document 1).

  The tactile sensor described in Patent Document 1 has a cantilever structure that extends from an edge of an opening formed in a sensor substrate. The structure includes a flat plate-like sensitive portion, a sensitive portion, and a sensor substrate. And a hinge portion connecting the two. A conductive magnetic film is formed on the sensitive part of the structure, a piezoresistive film is formed on the hinge part, and the conductive magnetic film and the piezoresistive film are electrically connected. In addition, an electrode is provided in the hinge portion, and the hinge portion is bent by pressure, so that a current generated by the piezoresistance of the hinge portion flows from the electrode. In this tactile sensor, a plurality of structures as described above are formed on the sensor substrate, and some of these structures stand up with respect to the sensor substrate and the other part is parallel to the sensor substrate. Is held in. Further, an elastic body is provided on the sensor substrate, and the upright structure is embedded in the elastic body. The shearing force can be measured by the standing structure, and the positive pressure can be measured by the structure parallel to the substrate surface. Here, in this tactile sensor, a shearing force is detected by a structure standing up with respect to the sensor substrate, and a positive pressure is detected by a structure held parallel to the sensor substrate. Further, the standing structure is formed by bending a flat structure by a magnetic force.

JP 2006-208248 A

  By the way, in the tactile sensor as described in Patent Document 1, the structure that stands up with respect to the sensor substrate is separated from the structure that is held parallel to the sensor substrate, and shear force is generated by the standing structure. A positive pressure is detected by a structure that is detected and parallel to the substrate. Such a structure for detecting a shear force needs to bend the structure for detecting a positive pressure by a magnetic force, and has a complicated three-dimensional structure, so that the productivity is low and the production cost increases. There is.

  In view of the above problems, an object of the present invention is to provide an ultrasonic sensor, a tactile sensor, and a gripping device that can detect contact of a contact object with a simple configuration.

An ultrasonic sensor of the present invention includes a substrate, a plurality of ultrasonic elements provided on the substrate, an elastically deformable elastic film disposed in contact with the plurality of ultrasonic elements, and an inside of the elastic film And an ultrasonic reflector capable of reflecting ultrasonic waves, wherein the ultrasonic reflector has an element facing surface facing the ultrasonic element corresponding to each of the plurality of ultrasonic elements. It is characterized by having a plurality.
Here, the “element facing surface facing the ultrasonic element” described in the present invention means that the ultrasonic element exists in a projection space in the normal direction of the element facing surface.

In the present invention, the ultrasonic reflector has a plurality of element facing surfaces, and the substrate is provided with a plurality of ultrasonic elements facing these element facing surfaces. In such a structure, an ultrasonic wave is transmitted from the ultrasonic element, and an ultrasonic wave reflected by the element facing surface facing the ultrasonic element is received by the ultrasonic element, from the ultrasonic wave transmission timing to the ultrasonic wave reception timing. By measuring the time (TOF data), it is possible to detect the distance from the ultrasonic element to the element facing surface.
When the contact object comes into contact with the elastic film and the elastic film is elastically deformed, the ultrasonic reflector is moved to a position corresponding to the deformation of the elastic film. At this time, by calculating the difference between the TOF data before deformation of the elastic film and the TOF data after deformation of the elastic film, the movement direction and movement amount of each element facing surface can be obtained. If the moving direction and moving amount of each element facing surface are known, it is possible to analyze the moving direction and moving distance of the entire ultrasonic reflector, and it is possible to calculate the stress acting on the elastic film. It becomes.
In such a configuration, the elastic film is formed on the substrate on which the ultrasonic element is disposed, and the ultrasonic reflector is embedded in the elastic film. For example, a three-dimensional detection member is formed on the substrate. Compared to such a configuration, the configuration can be simplified, the productivity can be improved, and the production cost can be reduced.

  In the ultrasonic sensor according to the present invention, when the one axis along the surface of the substrate is an X axis and the direction orthogonal to the X axis is along the surface of the substrate and the Y axis and the Z axis, the ultrasonic reflector is , A top located closest to the substrate, a first element facing surface continuously provided in the + X direction on the X axis from the top, and a first element provided continuously in the −X direction on the X axis from the top. Two element facing surfaces, and the first element facing surface is a straight line parallel to the Y axis, and a straight line inclined at a first tilt angle that moves away from the substrate toward the + X direction on the XZ plane, The second element facing surface is a straight line parallel to the Y axis and a straight line inclined at a second inclination angle away from the substrate as it goes in the -X direction on the XZ plane. A plane that is defined, on the substrate, It is preferable that the first ultrasonic element facing the first element opposing surfaces, and the second ultrasonic element facing the second element facing surfaces are disposed along the X axis.

  In the present invention, the amount of movement in the normal direction of the first element facing surface when the ultrasonic reflector is moved by the first element facing surface and the first ultrasonic element of the ultrasonic reflector (the first normal vector). ) Can be calculated, and the movement amount (second normal vector) in the normal direction of the second element facing surface when the ultrasonic reflector moves can be calculated by the second element facing surface and the second ultrasonic element. It becomes. Also, a vector component (first component vector) in the second inclination angle direction of the first normal vector and a vector component (second component vector) in the first inclination angle direction of the second normal vector are calculated. Is possible. Here, the first component vector and the second component vector do not include a movement amount component in the direction along the Y axis (hereinafter referred to as the Y axis direction). It is possible to calculate a movement vector (XZ movement vector) in the XZ plane of the acoustic wave reflector. Therefore, the XZ movement vector is decomposed into a vector component parallel to the X-axis and a vector component parallel to a direction along the Z (hereinafter referred to as the Z-axis direction). , The amount of movement in the direction along the X-axis (hereinafter referred to as the X-axis direction) can be calculated, the force acting on the elastic film in the Z-axis direction (positive pressure), and the elastic film The force acting in the X-axis direction (X-direction shear force) can be calculated. That is, by using the ultrasonic reflector and the ultrasonic element configured as described above, the amount of movement of the ultrasonic reflector in the Z-axis direction, the amount of movement in the X-axis direction, and the positive pressure can be easily performed only by vector calculation. , And the X-direction shear force can be calculated.

  In the ultrasonic sensor of the present invention, it is preferable that the first tilt angle and the second tilt angle are 45 degrees with respect to the X axis.

  In the present invention, the first inclination angle and the second inclination angle are each set to 45 degrees with respect to the X axis. For this reason, the first component vector and the first normal vector are the same, and the second component vector and the second normal vector are the same. Accordingly, the vector calculation as described above can be simplified, and the amount of movement of the ultrasonic reflector in the Z-axis direction, the amount of movement in the X-axis direction, the positive pressure, and the X-direction shear force can be more easily determined. Can be calculated.

  In the ultrasonic sensor of the present invention, the ultrasonic reflector is provided continuously from the top in the + Y direction on the Y axis and continuously from the top to the −Y direction on the Y axis. A fourth element facing surface, wherein the third element facing surface is a straight line that is parallel to the X axis and a straight line that is inclined at a third tilt angle that moves away from the substrate toward the + Y direction on the YZ plane. And the fourth element facing surface is a straight line that is parallel to the X axis and a straight line that is inclined at a fourth inclination angle that moves away from the substrate toward the -Y direction on the YZ plane. A third ultrasonic element facing the third element facing surface and a fourth ultrasonic element facing the fourth element facing surface in the Y-axis direction on the substrate. It is preferable to arrange along.

  In the present invention, in addition to the above, the amount of movement in the normal direction of the third element facing surface (third normal vector) and the method of the fourth element facing surface that do not include the moving component in the X-axis direction The amount of movement in the line direction (fourth normal vector) can be calculated, and the vector component (third component vector) in the fourth inclination angle direction of these third normal vectors, the third of the fourth normal vectors. It is possible to calculate a vector component (fourth component vector) in the tilt angle direction. Therefore, it is possible to calculate a movement vector (YZ movement vector) of the ultrasonic reflector in the YZ plane from the combined vector of the third component vector and the fourth component vector. From this YZ movement vector, the ultrasonic wave can be calculated. The amount of movement of the reflector in the Y-axis direction and the force acting in the Y-axis direction of the elastic film (Y-direction shearing force) can be easily calculated. Further, based on the X-direction shear force and the Y-direction shear force calculated by the above invention, the magnitude of the shear force in the XY plane and the direction of the shear force can be easily calculated.

  In the ultrasonic sensor according to the aspect of the invention, it is preferable that the third inclination angle and the fourth inclination angle are 45 degrees with respect to the Y axis.

  In the present invention, as in the above-described invention, the third inclination angle and the fourth inclination angle are set to 45 degrees with respect to the Y axis, respectively, so that the third component vector and the third normal vector are the same. Thus, the fourth component vector and the fourth normal vector are the same. Therefore, the vector calculation as described above can be further simplified, and the movement amount of the ultrasonic reflector in the Y-axis direction and the Y-direction shear force can be calculated more easily.

  In the ultrasonic sensor of the present invention, the top portion is a fifth element facing surface parallel to the surface of the substrate, and a fifth ultrasonic element facing the fifth element facing surface is provided on the substrate. It is preferable that it is disposed.

In the present invention, the amount of movement of the ultrasonic reflector in the Z-axis direction can be calculated by the fifth element facing surface and the fifth ultrasonic element.
Here, as described above, the amount of movement of the ultrasonic reflector in the Z-axis direction can be calculated from the XZ movement vector and the YZ movement vector, but the apex at the position closest to the substrate (fifth element facing surface). The amount of movement of the ultrasonic reflector in the Z-axis direction can be detected with higher accuracy by calculating the amount of movement by the fifth ultrasonic element. Using the amount of movement of the ultrasonic reflector detected by the fifth element facing surface and the fifth ultrasonic element in the Z-axis direction, the amount of movement of the ultrasonic reflector in the X-axis direction and the amount of movement in the Y-axis direction By calculating the above, it is possible to calculate a more accurate movement amount, and it is possible to calculate a more accurate value when calculating the positive pressure and the shearing force.

  In the ultrasonic sensor of the present invention, it is preferable that the ultrasonic reflector has a quadrangular pyramid shape.

In this invention, since the ultrasonic reflector has a quadrangular frustum shape having first to fifth element facing surfaces, as described above, the Z-axis direction movement amount, the X-axis direction movement amount of the ultrasonic reflector, and The amount of movement in the Y-axis direction can be detected with high accuracy.
In addition, when these element facing surfaces are each formed of a flat surface, the ultrasonic reflection surface can be increased. For example, when an omnidirectional diffusing ultrasonic wave (an ultrasonic wave having no directivity) is transmitted from an ultrasonic element having a predetermined area and the ultrasonic wave is reflected by a spherical ultrasonic reflector, Of the surface, only one point can reflect the ultrasonic wave in the direction of the ultrasonic element. In contrast, in the case of a quadrangular pyramid shaped ultrasonic reflector, the ultrasonic wave reflected in the region where the ultrasonic element exists in the normal direction of each ultrasonic facing surface is reflected to the ultrasonic element. Will be received. As a result, the ultrasonic wave reception sensitivity is improved, and the detection accuracy can be improved.

  In the ultrasonic sensor of the present invention, the elastic film, the ultrasonic reflector, and a plurality of the ultrasonic elements facing the element-opposing surfaces of the ultrasonic reflector are formed on the substrate. It is preferable that the sensor bodies are arranged in a plurality of arrays.

  In the present invention, it is possible to measure the amount of strain and stress of the elastic film when a contact object comes into contact with the elastic film in the sensor body by one sensor body, and such sensor bodies are arranged in an array. Thus, for example, regardless of the position of the contact surface on the contact surface having a certain area, the stress can be detected by any sensor body.

  In the ultrasonic sensor according to the present invention, an ultrasonic element for proximity detection that transmits ultrasonic waves in the air and receives ultrasonic waves reflected by a contact object between the adjacent sensor bodies on the substrate. Is preferably provided.

  In this invention, the ultrasonic sensor is provided with an ultrasonic element for proximity detection, and the distance to the contact object close to the ultrasonic sensor can be detected. In such a configuration, for example, in a state in which the distance between the ultrasonic sensor detected by the proximity detecting ultrasonic element and the contact object is a predetermined specified value, ultrasonic waves are transmitted from each ultrasonic element. Control such as output is also possible, and energy saving can be achieved.

  The tactile sensor of the present invention includes the ultrasonic sensor as described above, and a control unit that controls transmission and reception of ultrasonic waves of each ultrasonic element of the ultrasonic sensor.

  In the present invention, the tactile sensor includes the ultrasonic sensor as described above. Therefore, by controlling the ultrasonic transmission / reception of the ultrasonic sensor by the control unit, the stress such as the shearing force or the pressing force when the contact object contacts the elastic film is detected with a simple configuration as described above. be able to.

  In the tactile sensor of the present invention, the control unit is reflected by the ultrasonic reflector from an ultrasonic wave transmission control unit that transmits ultrasonic waves from the ultrasonic element, and an ultrasonic wave transmission timing of the ultrasonic element. Based on the time measured by the time measurement unit that measures the time until the ultrasonic wave is received by the ultrasonic element and the time measured by the time measurement unit, the moving amount and moving direction of the ultrasonic reflector are calculated. It is preferable that a movement amount calculation unit is provided.

In this invention, the ultrasonic transmission timing of each ultrasonic element is controlled by the ultrasonic transmission control unit, the time from the ultrasonic transmission timing to the ultrasonic reception timing is measured by the time measurement unit, and the movement amount calculation unit Based on the measured time, the amount of movement of the ultrasonic reflector is calculated.
Therefore, by calculating the time from the ultrasonic wave transmission timing to the ultrasonic wave reception timing for each ultrasonic element, the movement vector of the element facing surface of the ultrasonic reflector corresponding to each ultrasonic element is calculated. Can do. Therefore, as described above, by combining these movement vectors, it is possible to easily calculate the movement amount and the movement vector as the entire ultrasonic reflector.

  In the tactile sensor of the present invention, the control unit acts on the elastic film based on the moving amount and moving direction of the ultrasonic reflector calculated by the moving amount calculating unit and the Young's modulus of the elastic film. It is preferable to provide a stress calculation unit for calculating the stress to be performed.

  In the present invention, the stress calculation unit calculates the stress acting on the elastic film by multiplying the Young's modulus of the elastic film by the movement amount of the ultrasonic reflector calculated by the movement amount calculation unit. That is, the positive pressure can be calculated based on the amount of movement of the ultrasonic reflector in the Z-axis direction calculated by the movement amount calculation unit and the Young's modulus of the elastic film, and the XY plane direction of the ultrasonic reflector The shearing force can be calculated on the basis of the amount of movement at and the Young's modulus of the elastic film.

  In the tactile sensor of the present invention, the ultrasonic sensor includes a plurality of the ultrasonic elements facing the element facing surfaces of the elastic film, the ultrasonic reflector, and the ultrasonic reflector on the substrate. And a plurality of sensor bodies are arranged in an array, and the tactile sensor is in contact with the elastic film against stress acting on the elastic film. A storage unit that stores correlation data in which the state of the contact object is recorded; the stress calculated by the stress calculation unit; and a contact object determination unit that determines the state of the contact object based on the correlation data; It is preferable to provide.

  Here, the correlation data in which the state of the contact object in contact with the elastic film with respect to the stress acting on the elastic film, which is stored in the storage unit, is recorded, for example, of the contact object with respect to the stress acting on the elastic film. It may be data in which the roughness of the contact surface is recorded, or data in which the material type of the contact object with respect to the stress acting on the elastic film is recorded. For example, when the contact object is an elastic body, the softness of the elastic body against the stress acting on the elastic film may be recorded.

In this invention, a contact thing discrimination | determination part reads the above correlation data from a memory | storage part, and discriminate | determines the state of the contact thing with respect to the stress calculated in the stress calculation part from this correlation data.
In such a configuration, for example, when the roughness data of the contact surface of the contact object with respect to the stress is recorded as the correlation data, the roughness of the contact object in contact with the elastic film can be obtained. The material of the contact surface of the contact object can also be obtained. Further, when the material of the contact surface of the contact object with respect to the stress is recorded as the correlation data, the material on the contact surface of the contact object can be directly detected from the calculated stress. Furthermore, as the correlation data, for example, when softness data of the contact object with respect to stress is recorded, for example, the kneading state of the bread dough is discriminated by a touch sensor to determine whether or not the optimum kneading state is determined. You can also

  A gripping device of the present invention is a gripping device that includes the above-described tactile sensor and grips an object, and grips the object, and the touch sensor is provided on a contact surface that contacts the object. At least a pair of grip arms, grip detection means for detecting the slip state of the object based on a signal output from the tactile sensor, and drive control for controlling the drive of the grip arm based on the slip state And means.

In the present invention, as described above, by measuring the shearing force when the object to be grasped is measured by the tactile sensor, the object is in a state of sliding off from the grasping arm or in a state of being grasped. It becomes possible to measure whether or not. That is, in the operation of gripping the target object, in a state where the target object is not sufficiently gripped, a shearing force corresponding to the dynamic friction force works, and the shearing force increases as the gripping force increases. On the other hand, when the gripping force is increased and the shearing force corresponding to the static frictional force is detected, the gripping of the object is completed, and the static frictional force is constant even when the gripping force is increased, so the shearing force also changes. do not do. Therefore, for example, by gradually increasing the gripping force of the object and detecting when the shearing force no longer changes, the object can be gripped with a minimum gripping force without damaging the object. Can do.
Further, as described above, the tactile sensor constituting the gripping device has a simple configuration in which an elastic film in which an ultrasonic element and an ultrasonic reflector are embedded is laminated on a substrate, and is easy. Even in a gripping device using such a tactile sensor, the structure can be similarly simplified, and the manufacture is facilitated.

It is a top view which shows schematic structure of the sensor main body of the tactile sensor of 1st embodiment which concerns on this invention. It is sectional drawing which cut the sensor main body of 1st embodiment in the XZ plane. It is sectional drawing which cut the sensor main body of 1st embodiment in the YZ plane. It is a block diagram which shows schematic structure of the tactile sensor of 1st embodiment. FIG. 3 is a cross-sectional view illustrating a state in which the ultrasonic reflector is moved by the contact object coming into contact with the elastic film. It is explanatory drawing for calculating the movement amount of an ultrasonic reflector when an ultrasonic reflector moves to a predetermined position from an initial state. It is a flowchart of the stress calculation process of the tactile sensor of the first embodiment. It is explanatory drawing for calculating the movement amount of an ultrasonic reflector when the ultrasonic reflector in 2nd embodiment moves to the predetermined position from the initial state. It is a top view which shows the structure of the sensor array in the tactile sensor of 3rd embodiment. FIG. 10 is a cross-sectional view illustrating a cross-sectional structure of two sensor bodies adjacent to each other in the sensor array in FIG. 9. It is a block diagram which shows schematic structure of the control part in the tactile sensor of 3rd embodiment. It is an apparatus block diagram which shows schematic structure of the holding | gripping apparatus of 4th embodiment. The figure which shows the relationship between the positive pressure and shear force which act on the tactile sensor in the holding | grip operation | movement of the holding | gripping apparatus of 4th embodiment is shown. It is a flowchart which shows the holding | grip operation | movement of the holding | grip apparatus by control of the control apparatus of 4th embodiment. It is a timing diagram which shows the transmission timing of the drive control signal to an arm drive part, and the detection signal output from a tactile sensor at the time of holding | grip operation | movement of the holding | gripping apparatus of 4th embodiment. It is a block diagram which shows schematic structure of the iron which concerns on 5th embodiment. It is a flowchart which shows operation | movement of the iron of 5th embodiment.

[First embodiment]
Hereinafter, a tactile sensor according to a first embodiment of the present invention will be described with reference to the drawings.
[1. (Configuration of tactile sensor)
FIG. 1 is a plan view showing a schematic configuration of a sensor body 10 (ultrasonic sensor) in the tactile sensor 1 of the first embodiment, and FIG. 2 is a cross-sectional view of the sensor body 10 taken along the XZ plane. 3 is a cross-sectional view of the sensor body 10 taken along the YZ plane.

The tactile sensor 1 includes an ultrasonic sensor including at least one sensor body 10 and a control unit 30 (see FIG. 4) described later. As shown in FIG. 1, the sensor body 10 is configured by laminating a support film 14, an ultrasonic element 20, and an elastic film 15 on a substrate 11, and an ultrasonic reflection is formed inside the elastic film 15. The body 16 is embedded. The tactile sensor 1 is a sensor that detects a positive pressure and a shearing force applied when a contact object comes into contact with the elastic film 15.
In the first embodiment, an example in which one sensor main body 10 is provided as an ultrasonic sensor is shown. However, the present invention is not limited to this, and a configuration in which a plurality of these sensor main bodies 10 are provided as an ultrasonic sensor is also possible. Good. An ultrasonic sensor having a configuration in which a plurality of sensor bodies 10 are arranged in an array will be described in a third embodiment described later.

(1-1. Configuration of substrate)
The substrate 11 is made of, for example, Si and has a thickness dimension of, for example, 200 μm. As shown in FIGS. 1 to 3, the substrate 11 has five openings 111 for one ultrasonic reflector 16. Specifically, as shown in FIG. 1, in the plan view (sensor plan view) when the substrate 11 is viewed from the thickness direction, the installation position of the ultrasonic reflector is the origin, and the X axis is When the Y axis is set in the direction, the openings 111 are provided at the coordinate positions (a, 0), (−a, 0), (0, a), (0, −a), and (0, 0), respectively. It has been.
The opening 111 is formed in a circular shape in a plan view (sensor plan view) when the substrate 11 is viewed from the thickness direction of the substrate 11, but may be formed on a rectangle, for example. Further, although the opening 111 penetrating the substrate 11 in the thickness direction is illustrated, for example, a concave groove is formed by etching or the like on the surface of the substrate 11 on the elastic film 15 side (the upper side in FIGS. 2 and 3). It is good also as a structure. Furthermore, although the structure which forms the support film 14 on the board | substrate 11 was illustrated, the concave groove | channel was formed by the etching etc. from the surface (lower side of FIG. 2, FIG. 3) on the opposite side to the elastic film 15 of the board | substrate 11. FIG. The groove bottom may be the support film 14 and the inside of the groove may be the opening 111.

(1-2. Configuration of ultrasonic element)
The ultrasonic element 20 (20A, 20B, 20C, 20D, 20E) is disposed in an inner region of the opening 111 in the sensor plan view. Here, the first ultrasonic element 20A is arranged at the coordinates (a, 0), the second ultrasonic element 20B is arranged at the coordinates (−a, 0), and the coordinates (0, a) are arranged. The third ultrasonic element 20C is arranged, the fourth ultrasonic element 20D is arranged at the coordinates (0, -a), and the fifth ultrasonic element 20E is arranged at the coordinates (0, 0). Yes.
These ultrasonic elements 20 include an opening 111, a support film 14 (membrane 141) that closes the opening 111, a film-like piezoelectric film 21, a lower electrode 22 disposed between the piezoelectric film 21, and an upper part And the electrode 23.

Although not shown, the support film 14 is composed of an SiO ₂ layer formed on the substrate 11 with a thickness of 3 μm, for example, and a ZrO ₂ layer with a thickness of 400 nm stacked on the SiO ₂ layer, for example. It is formed by a two-layer structure. Here, the ZrO ₂ layer is a layer formed in order to prevent the piezoelectric film 21 from being peeled off when the ultrasonic element 20 described later is baked and formed. That is, when the piezoelectric film 21 is formed by, for example, PZT, the no ZrO ₂ layer is formed during firing, Pb contained in the piezoelectric film 21 is diffused into the SiO ₂ layer, it lowers the melting point of the SiO ₂ layer, Bubbles are generated on the surface of the SiO ₂ layer, and PZT is peeled off by the bubbles. Further, when there is no ZrO ₂ layer, there is a problem that the bending efficiency with respect to the distortion of the piezoelectric film 21 is lowered. On the other hand, when the ZrO ₂ layer is formed on the SiO ₂ layer, it is possible to avoid inconveniences such as peeling of the piezoelectric film 21 and a decrease in the bending efficiency.
In the following description, a region of the support film 14 that closes the opening 111 in the sensor plan view as shown in FIG.

The piezoelectric film 21 is formed, for example, by forming PZT (lead zirconate titanate) into a film shape having a thickness dimension of, for example, 500 nm. In the present embodiment, PZT is used as the piezoelectric film 21, but any material can be used as long as it is a material capable of generating an electric charge by changing the stress of the film, for example, lead titanate (PbTiO ₃ ). Lead zirconate (PbZrO ₃ ), lead lanthanum titanate ((Pb, La) TiO ₃ ), aluminum nitride (AlN), zinc oxide (ZnO), polyvinylidene fluoride (PVDF), and the like may be used.

  The lower electrode 22 and the upper electrode 23 are electrodes formed across the film thickness direction of the piezoelectric film 21, the lower electrode 22 is formed on the surface of the piezoelectric film 21 facing the membrane 141, and the upper electrode 23 is It is formed on the surface opposite to the surface on which the lower electrode 22 is formed.

The lower electrode 22 is a film-like electrode having a thickness dimension of, for example, 200 nm, and is formed in the membrane 141. The lower electrode 22 may be any conductive thin film having conductivity, but in the present embodiment, for example, a laminated structure film of Ti / Ir / Pt / Ti is used.
The upper electrode 23 is a film-like electrode having a thickness dimension of, for example, 50 nm. The upper electrode 23 is formed so as to cover the upper surface of the piezoelectric film 21.

  Further, as shown in FIG. 1, a lower electrode line 22 </ b> A extending from the outer periphery of the lower electrode 22 and an upper electrode line 23 </ b> A extending from the outer periphery of the upper electrode 23 are formed on the support film 14, respectively. Has been. These electrode wires 22A and 23A are led to a terminal pad (not shown) provided on the outer peripheral portion of the substrate 11, for example, and connected to a control unit 30 described later from the terminal pad.

Such an ultrasonic element 20 vibrates by a signal (AC voltage) input from the control unit 30 and transmits ultrasonic waves to the elastic film 15. Specifically, when an AC voltage is applied from the control unit 30 between the lower electrode 22 and the upper electrode 23, the piezoelectric film 21 expands and contracts according to the applied voltage. Thereby, the support film 14 vibrates and ultrasonic waves are transmitted to the elastic film 15 side. In the present embodiment, diffusion ultrasonic waves that diffuse radially in all directions are output from the ultrasonic element 20.
Further, the ultrasonic element 20 receives the ultrasonic wave input from the elastic film 15 and outputs a reception signal to the control unit 30. Specifically, when an ultrasonic wave is input from the elastic film 15 and the support film 14 vibrates in a state where no voltage is applied between the electrodes 21 and 22, the piezoelectric film 21 expands and contracts due to the vibration of the support film 14. A potential difference is generated between the lower electrode 22 side and the upper electrode 23 side of the piezoelectric film 21 in accordance with the expansion / contraction amount, and a current from the piezoelectric film 21 flows through the lower electrode 22 and the upper electrode 23 to output an electric signal (received signal). Is done.

(1-3. Configuration of elastic film and ultrasonic reflector)
The elastic film 15 is a film formed so as to cover the support film 14 and the ultrasonic element 20 as described above, and also functions as a protective film for the ultrasonic element 20. In this embodiment, for example, PDMS (PolyDiMethylSiloxane) is used as the elastic film 15, but the elastic film 15 is not limited thereto, and may be formed of other elastic materials such as elastic synthetic resin. Further, the thickness dimension of the elastic film 15 is not particularly limited, but is, for example, 300 μm.

  Further, a contact layer 151 is formed on the surface of the elastic film 15 as shown in FIGS. The contact layer 151 needs to always maintain a constant coefficient of friction in order to transmit the shearing force to the elastic film 15 to be distorted when the contact object comes into contact and is displaced in the shearing direction. It is preferably formed of a material or the like. Moreover, when the ultrasonic wave transmitted from the ultrasonic element 20 is reflected by the contact layer 151, the ultrasonic wave is irregularly reflected inside the elastic film 15, and the measurement accuracy in each ultrasonic element 20 is lowered. There is a fear. For this reason, the contact layer 151 is preferably formed in a shape that absorbs or scatters ultrasonic waves on the surface. As such a contact layer 151, for example, a felt or nonwoven fabric, a PET film to which a polymer made by mixing silica or the like into a porous structure, and the like are bonded can be exemplified.

The ultrasonic reflector 16 is embedded in the elastic film 15 at the position of the coordinates (0, 0). The ultrasonic reflector 16 has an acoustic impedance different from that of the elastic film 15. Accordingly, the ultrasonic wave traveling through the elastic film 15 is reflected by the surface of the ultrasonic reflector 16.
As shown in FIGS. 1 to 3, the ultrasonic reflector 16 is formed in a regular quadrangular pyramid shape. In the present embodiment, the vessel-shaped ultrasonic reflector 16 whose outer peripheral surface has a regular quadrangular pyramid shape is illustrated, but for example, a block-shaped square frustum-shaped ultrasonic reflector may be used.

Specifically, the ultrasonic reflector 16 includes four trapezoidal element facing surfaces 161 </ b> A to 161 </ b> D around a fifth element facing surface 161 </ b> E that is a top portion facing the substrate 11.
As shown in FIGS. 1 and 2, the first element facing surface 161 </ b> A is continuous to the + X direction side of the fifth element facing surface 161 </ b> E, and has an angle of 45 degrees in the direction away from the substrate 11 toward the + X direction on the XZ plane. Is a plane defined by a straight line inclined at and a straight line parallel to the Y-axis. The second element facing surface 161B is continuous to the −X direction side of the fifth element facing surface 161E, and a straight line inclined at an angle of 45 degrees in the direction away from the substrate 11 toward the −X direction on the XZ plane, and the Y axis It is a plane defined by a straight line parallel to.
As shown in FIGS. 1 and 3, the third element facing surface 161 </ b> C is continuous to the + Y direction side of the fifth element facing surface 161 </ b> E and is 45 degrees away from the substrate 11 toward the + Y direction on the YZ plane. It is a plane defined by a straight line inclined at an angle of 5 and a straight line parallel to the X axis. The fourth element facing surface 161D is continuous to the −Y direction side of the fifth element facing surface 161E, and a straight line inclined at an angle of 45 degrees in the direction away from the substrate 11 toward the −Y direction on the YZ plane, and the X axis Is a plane defined by a straight line parallel to.
Here, as shown in FIGS. 2 and 3, the ultrasonic elements 20 </ b> A to 20 </ b> E are positioned on the normal direction of the element facing surfaces 161 </ b> A to 161 </ b> E, that is, the method of the element facing surfaces 161 </ b> A to 161 </ b> E. It is located in the projection space in the line direction.

(1-4. Configuration of control unit)
FIG. 4 is a block diagram illustrating a schematic configuration of the touch sensor 1.
As shown in FIG. 4, the control unit 30 includes an element switching circuit 31, a transmission / reception switching circuit 32, a transmission / reception switching control unit 33, an ultrasonic signal transmission circuit 34, a time measurement unit 35, a storage unit 36, And an arithmetic processing unit 37. The element switching circuit 31, the transmission / reception switching circuit 32, the transmission / reception switching control unit 33, and the ultrasonic signal transmission circuit 34 constitute an ultrasonic transmission control unit of the present invention.

The element switching circuit 31 is a switching circuit that switches the ultrasonic element 20 to be driven among the five ultrasonic elements 20 of the sensor body 10.
In the tactile sensor 1 of the present embodiment, while transmission / reception of ultrasonic waves from one ultrasonic element 20 is being performed, output of drive signals to other ultrasonic elements 20 and reception from other ultrasonic elements 20 are performed. No signal is received. As a result, the ultrasonic element 20 to be driven receives the ultrasonic waves transmitted from the other ultrasonic elements 20, and the inconvenience of detecting noise or reception from the ultrasonic elements 20 other than the drive target. The inconvenience that a signal is detected can be avoided.
The element switching circuit 31 includes, for example, a group of terminals connected to the lower electrode line 22A and the upper electrode line 23A of each ultrasonic element 20, and based on the command signal input from the transmission / reception switching control unit 33, the command signal And a terminal group corresponding to the ultrasonic element 20 corresponding to 1 and the transmission / reception switching circuit 32 are connected. The terminal group corresponding to the ultrasonic element 20 that is not driven may be configured not to be driven by connecting both the lower electrode line 22A and the upper electrode line 23A to GND, for example.

The transmission / reception switching circuit 32 is a switching circuit that switches the connection state based on a mode switching signal input from the transmission / reception switching control unit 33.
Specifically, when a control signal for switching to the ultrasonic transmission mode is input from the transmission / reception switching control unit 33, the transmission / reception switching circuit 32 receives the drive signal input from the ultrasonic signal transmission circuit 34 as the sensor body 10. Are switched to a switching state capable of being output to the ultrasonic elements 20A to 20E.
On the other hand, when a control signal for switching to the ultrasonic reception mode is input from the transmission / reception switching control unit 33, the transmission / reception switching circuit 32 receives the reception signals input from the ultrasonic elements 20A to 20E of the sensor body 10 as a time measurement unit. 35 is switched to a switching state in which output is possible.

The transmission / reception switching control unit 33 switches between an ultrasonic transmission mode in which ultrasonic waves are transmitted from each ultrasonic element 20 and an ultrasonic reception mode in which ultrasonic waves are received by the ultrasonic elements 20.
Specifically, for example, when the power of the tactile sensor 1 is switched to the ON state, the transmission / reception switching control unit 33 first performs a process of switching to the ultrasonic transmission mode. In this process, the transmission / reception switching control unit 33 outputs a control signal for switching to the ultrasonic transmission mode to the transmission / reception switching circuit 32, and outputs a control signal for outputting a drive signal from the ultrasonic signal transmission circuit 34. The transmission / reception switching control unit 33 monitors the time measured by a timer (not shown) and performs a process of switching from the ultrasonic transmission mode to the ultrasonic reception mode after a predetermined transmission time has elapsed. Here, the transmission time should just be set to about the time when the burst wave of 1-2 frequency is transmitted from the ultrasonic element 20, for example. In the ultrasonic reception mode, the transmission / reception switching control unit 33 outputs a control signal for switching to the ultrasonic reception mode to the transmission / reception switching circuit 32, and the transmission / reception switching circuit 32 receives the reception signal input from the ultrasonic element 20. The time measurement unit 35 is switched to a connection state that can be input.

  The ultrasonic signal transmission circuit 34 transmits and receives a drive signal (drive pulse) for driving the ultrasonic element 20 when a control signal for outputting a drive signal is input from the transmission / reception switching control unit 33 in the transmission mode. Output to the switching circuit 32.

The time measuring unit 35 monitors the time measured by the time measuring unit and measures the time until the ultrasonic wave is received.
Specifically, the time measuring unit 35 counts the ultrasonic transmission timing at which the transmission / reception switching control unit 33 performs the process of switching to the ultrasonic transmission mode, that is, the time from when the ultrasonic wave is transmitted from the ultrasonic element 20. . The transmission / reception switching control unit 33 resets the time counted by the time measuring unit at the ultrasonic transmission timing. Then, when the transmission / reception switching control unit 33 performs a process of switching to the ultrasonic reception mode and a reception signal corresponding to the reflected ultrasonic wave received by the ultrasonic element 20 is input from the transmission / reception switching circuit 32 to the time measurement unit 35. The time measuring unit 35 acquires time (TOF data: Time Of Flight data) at the input timing. The acquired TOF data is input to the arithmetic processing unit 37.

The storage unit 36 stores various programs and various data for performing various processes of the arithmetic processing unit 37.
Specifically, the storage unit 36 stores in advance the Young's modulus of the elastic film 15, the sound velocity of the ultrasonic waves in the elastic film 15, various programs executed by the arithmetic processing unit 37, and the like. In addition, a configuration in which various data calculated by the arithmetic processing unit 37 is stored may be employed. Furthermore, the inclination angle of each element facing surface 161 of the ultrasonic reflector 16 may be recorded in the storage unit 36.

  The arithmetic processing unit 37 includes a movement amount calculation unit 371 and a stress calculation unit 372. Specifically, the arithmetic processing unit 37 includes a central arithmetic circuit, an arithmetic circuit such as a memory, a storage circuit, and the like. For example, a movement amount calculation program stored in the storage unit 36 is read by the central arithmetic circuit. When the processing is executed and executed, it functions as the movement amount calculation unit 371, and the stress calculation program stored in the storage unit 36 is read by the central processing circuit and executed, so that the stress calculation unit It functions as 372.

The movement amount calculation unit 371 is based on the TOF data input from the time measurement unit 35 and the sound velocity in the elastic film 15 stored in advance in the storage unit 36, that is, the movement amount of the ultrasonic reflector, that is, the elasticity. The amount of distortion of the film 15 is calculated.
The stress calculation unit 372 is a stress acting on the elastic film 15 based on the strain amount of the elastic film 15 calculated by the movement amount calculation unit 371 and the Young's modulus of the elastic film 15 stored in advance in the storage unit 36. Is calculated.
Details of the strain amount calculation method of the movement amount calculation unit 371 (the movement amount calculation method of the ultrasonic reflector 16) and the stress calculation method of the stress calculation unit 372 will be described later.

[2. Operation of the tactile sensor
Next, the measurement operation of the positive pressure and the shearing force by the tactile sensor 1 as described above will be described in detail with reference to FIG. 5, FIG. 6, and FIG. In the present embodiment, the following description will be made assuming that the rotation of the ultrasonic reflector 16 due to the distortion of the elastic film 15 is sufficiently small and can be ignored. Further, the detection of the amount of movement of the ultrasonic reflector 16 in the Y-axis direction and the detection of the shearing force in the Y-axis direction acting on the elastic film 15 are the detection of the amount of movement in the X-axis direction and the action of the elastic film 15. Since it can be calculated by the same processing as the detection of the shearing force in the Y-axis direction, description here is omitted.
FIG. 5 is a cross-sectional view showing a state in which the ultrasonic reflector 16 is moved by the contact L contacting the elastic film 15 in FIG. FIG. 6 is an explanatory diagram for calculating the amount of movement of the ultrasonic reflector 16 when the ultrasonic reflector 16 has moved from the initial state to a predetermined position. 5 and 6, the ultrasonic reflector 16 indicated by a two-dot chain line indicates an initial position P ₀ where the contact L does not contact, and the ultrasonic reflector 16 indicated by a solid line indicates the contact It shows the movement position P ₁ by L contact. FIG. 7 is a flowchart of the stress calculation process in the tactile sensor 1 of the first embodiment.

In the operation of detecting the positive pressure and the shearing force by the tactile sensor 1, as shown in FIG. 7, first, the control unit 30 performs a process of initializing the element setting variable n (n = 0) (step S1).
Thereafter, the control unit 30 performs a process of driving the ultrasonic element corresponding to the element setting variable n and acquiring TOF data.

  Specifically, the transmission / reception switching control unit 33 of the control unit 30 switches to the ultrasonic transmission mode. That is, the transmission / reception switching control unit 33 switches the element switching circuit 31 to a state in which signals can be transmitted / received to / from the nth ultrasonic element 20, transmits drive signals to the other ultrasonic elements 20, The reception of the reception signal from the sound wave element 20 is blocked. In addition, the transmission / reception switching control unit 33 switches the transmission / reception switching circuit 32 to a state in which the drive signal can be output to the ultrasonic element 20, and causes the ultrasonic signal transmission circuit 34 to generate the drive signal. To output. Thereby, ultrasonic waves of 1-2 burst waves are transmitted from the nth ultrasonic element 20 (step S2). Further, at this ultrasonic wave transmission timing, the transmission / reception switching control unit 33 resets the timer.

Thereafter, the transmission / reception switching circuit 32 switches to the ultrasonic reception mode, and switches the transmission / reception switching circuit 32 to a state in which the reception signal input from the ultrasonic element 20 can be output to the time measuring unit 35 (step S3).
As a result, when the reception signal is input, the time measuring unit 35 acquires the time of the timer, that is, the ultrasonic wave is transmitted from the ultrasonic element 20 and reflected by the ultrasonic reflector 16, and the ultrasonic element 20. The time (TOF data) until returning to is acquired (step S4). The time measuring unit 35 stores the acquired TOF data in the storage unit 36.
Here, the storage unit 36 accumulates and stores the acquired TOF data in order to perform a comparison process between the previously stored TOF data and the newly stored TOF data. For example, the storage unit 36 stores the TOF data acquired for the loop m−1 and the TOF data acquired for the loop m.

Next, the control unit 30 determines whether or not the value of the element setting variable n is 5 (the number of ultrasonic elements 20 provided in the sensor body 10) or more (step S5).
Here, when the control unit 30 determines that the element setting variable n is 4 or less, the control unit 30 adds 1 to the element setting variable n (step S6), and repeatedly performs the processing of steps S2 to S4.

On the other hand, when determining that the element setting variable n is 5, the control unit 30 determines whether the acquired TOF data is fluctuated as compared with the previously acquired TOF data (step S7). Note that, when the tactile sensor 1 is driven for the first time, for example, when the power is turned on, only the TOF data acquired in the first loop is stored, so the processing returns to step S1 and the processing of steps S1 to S5 is performed again. Perform the second loop of TOF data.
Further, when there is no change in the TOF data stored in the storage unit 36, that is, when the difference between the loop m-1st TOF data and the loop mth TOF data is within a preset threshold range. The control unit 30 again performs the processes of Steps S1 to S5 (the process of loop m + 1).

In this step S7, when the difference between the loop m-1st TOF data and the loop mth TOF data is equal to or larger than the threshold value, the control unit 30 performs a process of calculating the fluctuation amount of these TOF data. (Step S8).
Thus, when there is a change in the acquired TOF data, the tactile sensor 1 means that the contact object L is in contact with the elastic film 15 and the elastic film 15 is elastically deformed as shown in FIG. To do.

Thereafter, the movement amount calculation unit 371 calculates the movement amount of the ultrasonic reflector 16 based on the calculated fluctuation amount of the TOF data (step S9).
In step S9, the movement amount of the ultrasonic reflector 16 is calculated as follows.
That is, if the TOF data in a state where the ultrasonic reflector 16 is located at the initial position P ₀ is T ₀ and the TOF data when the ultrasonic reflector 16 is moved to the position P ₁ is T ₁ , the movement The amount calculation unit 371 calculates a movement amount M with respect to the variation amount of the TOF data by the following equation.

[Equation 1]

In the above formula (1), c is the speed of sound in the elastic film 15 and is stored in the storage unit 36 in advance.
Here, of the ultrasonic waves transmitted from the respective ultrasonic elements 20 (20A to 20E), the ultrasonic waves reflected by the element facing surfaces 161 (161A to 161E) and returned to the original ultrasonic elements 20 (20A to 20E). The sound wave component is an ultrasonic wave incident perpendicularly to the element facing surface 161 (161A to 161E). For example, of the ultrasonic waves transmitted from the first ultrasonic element 20A, an ultrasonic component incident perpendicularly to the first element facing surface 161A is reflected toward the first ultrasonic element 20A, and the first ultrasonic element Received at 20A.
Therefore, the amount of movement M obtained as described above is the amount of movement of each element facing surface 161 in the normal direction. In FIG. 6, the first method corresponding to the movement of the first element facing surface 161A in the normal direction. The line vector (A) is indicated by the second normal vector (B) corresponding to the movement in the normal direction of the second element facing surface 161B.

  In the tactile sensor 1 of the present embodiment, the element facing surfaces 161A and 161B of the ultrasonic reflector 16 are inclined at an angle of 45 degrees with respect to the X axis. Therefore, as shown in FIG. 6, the combined vector of the first normal vector (A) and the second normal vector (B) is a movement vector (XZ movement vector (C )), And the following vector expression is established.

[Equation 2]

Therefore, the movement amount calculation unit 371 calculates the XZ movement vector (C) based on the vector expression shown in the expression (2). Further, the movement amount calculation unit 371 converts the XZ movement vector (C) into an X shear direction vector (x) that is a component in the X axis direction and a positive pressure direction vector (z) that is a component in the Z axis direction. Decompose.
Here, the absolute value of the X shear direction vector (x) is the amount of movement of the ultrasonic reflector 16 in the X-axis direction, and the amount of distortion of the elastic film 15 in the X-axis direction. The absolute value of the positive pressure direction vector (z) is the amount of movement of the ultrasonic reflector 16 in the Z-axis direction and the amount of distortion of the elastic film 15 in the Z-axis direction.

Further, the movement amount calculation unit 371 calculates the amount of change in the TOF data until the ultrasonic wave transmitted from the fifth ultrasonic element 20E is reflected by the fifth element facing surface 161E and returns to the fifth ultrasonic element 20E. And based on Formula (1), the movement amount of the 5th element opposing surface 161E is calculated.
The amount of movement of the fifth element facing surface 161E is the amount of movement of the ultrasonic reflector 16 in the Z-axis direction, and was calculated based on the movement of the first element facing surface 161A to the fourth element facing surface 161D. The value is more accurate than the value. This is because the distance between the fifth element facing surface 161E and the fifth ultrasonic element 20E is between the other element facing surfaces 161A to 161D and the ultrasonic elements 20A to 20D corresponding to these element facing surfaces 161A to 161D. This is because it is smaller than the distance and the attenuation of ultrasonic waves and the like can be suppressed.
Therefore, the movement amount calculation unit 371 is calculated based on the measured movement amount in the Z-axis direction of the ultrasonic reflector 16 calculated by the fifth element facing surface 161E and the fifth ultrasonic element 20E, and the equation (2). The calculated movement amount is compared with the calculated movement amount in the Z-axis direction, and when these differences are equal to or larger than a predetermined value set in advance, the measurement movement amount is set as the movement amount in the Z-axis direction. In this case, the movement amount calculation unit 371 sets a positive pressure direction vector (z) based on the measured movement amount, and corrects the X shear direction vector (x) based on Expression (2). Also good.

  In the above, the case where the ultrasonic reflector 16 moves only in the ZX direction is exemplified, and the movement amount calculation unit 371 moves the ultrasonic reflector 16 in the Z axis direction (Z axis of the elastic film 15). The amount of distortion in the direction) and the amount of movement of the ultrasonic reflector 16 in the X-axis direction (the amount of distortion of the elastic film 15 in the X-axis direction) were calculated, but the movement of the ultrasonic reflector 16 in the Y-axis direction was calculated. The amount can be calculated by a similar method.

That is, the movement amount calculation unit 371 is the third movement amount that is the movement amount in the normal direction of the third element facing surface 161C from the variation amount of the TOF data acquired by the third element facing surface 161C and the third ultrasonic element 20C. A normal vector is calculated, and the fourth normal line, which is the amount of movement in the normal direction of the fourth element facing surface 161D from the variation amount of the TOF data acquired by the fourth element facing surface 161D and the fourth ultrasonic element 20D. Calculate the vector.
In addition, since the third element facing surface 161C and the fourth element facing surface 161D are inclined at 45 degrees with respect to the Y axis, the combined vector of the third normal vector and the fourth normal vector is reflected by ultrasonic waves. This is the YZ movement vector of the body 16.
Therefore, the movement amount calculation unit 371 calculates a YZ movement vector, and further decomposes the YZ movement vector into a positive pressure direction vector of the Z-axis direction component and a Y shear direction vector of the Y-axis direction component. This positive pressure direction vector becomes the amount of strain in the Z-axis direction of the elastic film 15, and the Y shear direction vector becomes the amount of strain in the Z-axis direction of the elastic film 15.

The movement amount calculation unit 371 calculates the movement direction and the movement amount of the ultrasonic reflector 16 in the XY plane by combining the X shear direction vector and the Y shear direction vector calculated as described above. May be.
Then, the movement amount calculation unit 371 stores the calculated movement amount of the ultrasonic reflector 16 in the storage unit 36.

After step S9, the stress calculation unit 372 of the control unit 30 calculates the stress acting on the elastic film 15 (step S10).
Specifically, the stress calculation unit 372 reads the Young's modulus of the elastic film 15 stored in the storage unit 36, and calculates the Young's modulus as the amount of strain in the X-axis direction of the elastic film 15 calculated by the movement amount calculation unit 371. Is multiplied by the shearing force in the X-axis direction.
Further, the stress calculation unit 372 calculates a positive pressure by multiplying the amount of strain in the Z-axis direction of the elastic film 15 calculated by the movement amount calculation unit 371 by the Young's modulus.
Similarly, the stress calculation unit 372 calculates the shear force in the Y-axis direction by multiplying the amount of strain in the Y-axis direction of the elastic film 15 calculated by the movement amount calculation unit 371 by the Young's modulus. When the movement amount of the ultrasonic reflector in the XY plane is calculated, the resultant force of the shear force in the X-axis direction and the shear force in the Y-axis direction is calculated by multiplying the Young's modulus of the movement amount. You can also.
Then, the stress calculation unit 372 stores the calculated positive pressure and shear force in the storage unit 36.

[3. Effect of First Embodiment)
As described above, the tactile sensor 1 according to the first embodiment includes the sensor body 10 and the control unit 30 that controls the sensor body 10. The sensor body 10 is embedded in the substrate 11, five ultrasonic elements 20 (20 </ b> A to 20 </ b> E) provided on the substrate 11, an elastic film 15 covering these ultrasonic elements 20, and the elastic film 15. The ultrasonic reflector 16 includes an element facing surface 161 that faces each of the ultrasonic elements 20 (20A to 20E).
The tactile sensor having such a configuration can detect the amount of movement and the direction of movement of each element facing surface 161 of the ultrasonic reflector 16 based on the amount of fluctuation of the TOF data obtained from each ultrasonic element 20, By multiplying these movement amounts by the Young's modulus of the elastic film 15, the stress acting on the elastic film 15 can be calculated.
In addition, since the configuration is such that the ultrasonic element 20 and the elastic film 15 are simply laminated on the substrate 11, the configuration can be simplified and productivity can be improved as compared with the case where a three-dimensional shear force detection structure is provided, for example. The production cost can be reduced.

In the tactile sensor 1 according to the present embodiment, the ultrasonic reflector 16 is formed in a regular quadrangular pyramid shape, and the first element facing surface 161 </ b> A constituting the regular quadrangular pyramid shape is a top portion facing the substrate 11. It is provided on the + X side of a certain fifth element facing surface 161E, is inclined by 45 degrees in a direction away from the substrate 11 toward the + X direction, and is formed by an inclined surface parallel to the Y axis. The second element facing surface 161B constituting the regular quadrangular pyramid shape is provided on the −X side of the fifth element facing surface 161E, and is inclined at 45 degrees in a direction away from the substrate 11 toward the −X direction. It is formed by an inclined surface parallel to the Y axis.
In such a configuration, the fluctuation amount of the TOF data acquired by the first ultrasonic element 20A and the first element facing surface 161A and the fluctuation amount of the TOF data acquired by the second ultrasonic element 20B and the second element facing surface 161B. The first normal vector (A) that is the amount of movement in the normal direction of the first element facing surface 161A and the second normal vector (the amount of movement in the normal direction of the second element facing surface 161B are B) can be calculated. Further, since the first element facing surface 161A and the second element facing surface 161B are inclined at 45 degrees with respect to the X axis, the movement amount calculation unit 371 calculates the first normal vector (A) and the first The XZ movement vector (C) of the ultrasonic reflector 16 can be easily calculated simply by calculating the combined vector of the two normal vectors (B). Further, the movement amount calculation unit 371 decomposes the XZ movement vector into a positive pressure direction vector (z) and an X shearing force direction vector (x) as shown in the equation (2), so that the elastic film 15 The strain amount in the Z-axis direction and the strain amount in the X-axis direction can be easily calculated.

  Similarly, the fluctuation amount of the TOF data acquired by the third ultrasonic element 20C and the third element facing surface 161C and the fluctuation amount of the TOF data acquired by the fourth ultrasonic element 20D and the fourth element facing surface 161D. The third normal vector, which is the amount of movement of the third element facing surface 161C in the normal direction, and the fourth normal vector, which is the amount of movement of the fourth element facing surface 161D in the normal direction, are calculated. it can. For this reason, the movement amount calculation unit 371 can easily calculate the YZ movement vector of the ultrasonic reflector 16 only by calculating the combined vector of the third normal vector and the fourth normal vector. The amount of strain in the Y-axis direction of the elastic film 15 can be easily calculated.

Further, similarly, the amount of movement in the normal direction of the fifth element facing surface 161E, that is, the ultrasonic reflector, from the variation amount of the TOF data acquired by the fifth ultrasonic element 20E and the fifth element facing surface 161E. The amount of movement of 16 in the Z-axis direction can be directly measured.
Here, the fifth element facing surface 161E constitutes the top of the ultrasonic reflector 16 and is disposed at a position closest to the substrate 11, and the fifth ultrasonic element 20E is provided directly below the fifth element facing surface 161E. ing. Therefore, the distance between the fifth element facing surface 161E and the fifth ultrasonic element 20E is shorter than the distance between the other element facing surfaces 161A to 161D and the corresponding ultrasonic elements 20A to 20D, and the elastic film 15, there is no attenuation of ultrasonic waves and the like, and highly accurate TOF data can be acquired. Therefore, by measuring the amount of movement of the ultrasonic reflector 16 in the Z-axis direction using such TOF data, the amount of movement can be measured with high accuracy.
Further, based on the amount of movement in the Z-axis direction measured with such high accuracy, the amount of movement of the ultrasonic reflector 16 in the XY shear direction can also be corrected, and more accurate measurement can be performed. it can.

  In addition, as described above, in the configuration using the regular quadrangular pyramid shaped ultrasonic reflector 16, each element facing surface 161 is formed by a flat surface, so that the ultrasonic reflection region can be enlarged. For example, when the ultrasonic reflector has a structure having a spherical shape, for example, among the ultrasonic waves transmitted from the ultrasonic element 20, the ultrasonic wave reflected by the ultrasonic element 20 is based on one point of the spherical surface. Since only the reflected ultrasonic waves are used, the received signal is small and the detection accuracy is deteriorated. Even in the case of a structure having a truncated cone shape, among the ultrasonic waves transmitted from the ultrasonic element 20, the ultrasonic wave reflected by the ultrasonic element 20 is only the ultrasonic wave reflected by a straight line of the curved surface. It becomes. On the other hand, in the quadrangular pyramid-shaped ultrasonic reflector 16, the ultrasonic wave reflected in the area region facing the ultrasonic element 20 in the element facing surface 161 is input to the ultrasonic element 20. Compared with the case of using an ultrasonic reflector having a spherical shape or a truncated cone shape, the received signal becomes larger and the detection accuracy can be improved.

And in the tactile sensor 1 of this embodiment, the control part 30 is acquired from the transmission / reception switching circuit 32, the transmission / reception switching control part 33, the ultrasonic signal transmission circuit 34, and each ultrasonic element 20 which comprise an ultrasonic transmission control part. Based on the received signal, the time measuring unit 35 for acquiring the TOF data, and the movement for calculating the moving amount and moving direction of the ultrasonic reflector based on the fluctuation amount of the TOF data acquired by the time measuring unit 35 A quantity calculation unit 371.
In such a tactile sensor 1, as described above, based on the TOF data acquired by the time measuring unit 35, a normal vector that is the amount of movement in the normal direction of each element facing surface 161 of the ultrasonic reflector 16. And the amount of movement of the ultrasonic reflector 16 in the Z-axis direction, the amount of movement in the X-axis direction, the amount of movement in the Y-axis direction, that is, the XYZ axes of the elastic film 15 based on these normal vectors. It is possible to easily calculate the amount of distortion in each direction.

  Further, the control unit 30 includes a stress calculation unit 372, and the stress acting on the elastic film 15 from the strain amount of the elastic film 15 calculated by the movement amount calculation unit 371 and the Young's modulus of the elastic film 15, that is, the elastic film 15 The acting shear force and positive pressure can be easily calculated.

[Second Embodiment]
Next, a tactile sensor 1 according to a second embodiment of the present invention will be described with reference to the drawings.
In the first embodiment, the first element facing surface 161A and the second element facing surface 161B of the ultrasonic reflector 16 are inclined at 45 degrees with respect to the X axis, and the third element facing surface 161C and the fourth element facing surface. The configuration in which 161D is inclined at 45 degrees with respect to the Y axis is illustrated.
On the other hand, in the second embodiment, the first element facing surface 161A and the second element facing surface 161B of the ultrasonic reflector 16 have 0 degree <θ <90 degrees (θ ≠ 45 degrees) with respect to the X axis. An example formed is shown below. The same applies to the case where the third element facing surface 161C and the fourth element facing surface 161D are formed at 0 degree <θ <90 degrees (θ ≠ 45 degrees) with respect to the Y axis. Omitted.

As in the first embodiment, when the angle θ is formed at 45 degrees, the combined vector of the first normal vector (A) and the second normal vector (B) is the XZ movement vector of the ultrasonic reflector 16. However, when θ ≠ 45 degrees as in the second embodiment, the movement amount calculation unit 371 calculates the XZ movement vector by different processing in step S9.
FIG. 8 is an explanatory diagram for calculating the amount of movement of the ultrasonic reflector 16 when the ultrasonic reflector 16 in the second embodiment moves from the initial state to a predetermined position. The tactile sensor 1 of the second embodiment has the same configuration as that of the first embodiment except that the first element facing surface 161A and the second element facing surface 161B of the ultrasonic reflector 16 are different in inclination angle. Therefore, the same reference numerals are given to the respective components, and the description thereof is omitted.

  In the tactile sensor 1 according to the second embodiment, when the contact object L comes into contact with the elastic film 15, when the elastic object 15 receives a positive pressure in the Z-axis direction or a shearing force along the XY direction from the contact object L, FIG. As shown in FIG. 4, the elastic film 15 is elastically deformed and distorted, and the position of the ultrasonic reflector embedded in the elastic film 15 is moved according to the elastic deformation of the elastic film 15.

Here, of the ultrasonic waves transmitted from the first ultrasonic element 20A, the ultrasonic component reflected by the first element facing surface 161A and returning to the first ultrasonic element 20A is directed to the first element facing surface 161A. Ultrasound incident perpendicularly. Therefore, similarly to the first embodiment, the movement amount calculation unit 371 calculates the first normal vector (A) and the second normal vector (B) based on the equation (1).
On the other hand, the XZ movement vector (C) of the ultrasonic reflector 16 is a vector component (first component vector ( ₁ ) along the inclination angle (first inclination angle θ ₁ ) of the second element facing surface 161B of the first element facing surface 161A. A ′)) and a vector vector (second component vector (B ′)) along the tilt angle (second tilt angle θ ₂ ) of the first element facing surface 161A of the second element facing surface 161B. Is done.

Therefore, as shown in FIG. 8, the movement amount calculation unit 371 decomposes the first normal vector (A) to calculate the first component vector (A ′), and decomposes the second normal vector (B). Then, the second component vector (B ′) is calculated. For this purpose, the first tilt angle θ ₁ and the second tilt angle θ ₂ are stored in advance in the storage unit 36 of the control unit 30, and the movement amount calculation unit 371 stores these tilt angles θ ₁ , θ _2. And the first component vector (A ′) and the second component vector (B ′) are calculated by the following equation (3).

[Equation 3]

  Thereafter, the movement amount calculation unit 371 calculates the XZ movement vector (C) by combining the first component vector (A ′) and the second component vector (B ′), and decomposes the XZ movement vector (C). Then, the positive pressure direction vector (z) and the X shear direction vector (x) are calculated.

[Operational effects of the second embodiment]
Even with the tactile sensor 1 as in the second embodiment, it is possible to obtain the same effects as the first embodiment. In addition, in the second embodiment, the positive pressure direction vector (z) is accurately obtained in any case where the inclination angle of each element facing surface 161 of the ultrasonic reflector 16 is 0 degree <θ <90 degrees. And the X shear direction vector (x) can be calculated.
Therefore, for example, the inclination angle of the ultrasonic reflector 16 can be set to 0 degree <θ <45 degrees. In this case, the thickness dimension of the ultrasonic reflector 16 in the Z-axis direction is set as compared with the first embodiment. The size can be reduced, and further downsizing of the touch sensor 1 can be promoted.

[Third embodiment]
Next, a tactile sensor according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 9 is a diagram illustrating a configuration of a sensor array in the tactile sensor according to the third embodiment. FIG. 10 is a cross-sectional view showing a cross-sectional structure of two sensor bodies 10 adjacent to each other in the sensor array 10A (ultrasonic sensor) in FIG. In addition, about the structure similar to 1st and 2nd embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
The tactile sensor 1A of the third embodiment includes a sensor array 10A having an array structure in which the sensor main bodies 10 of the first and second embodiments are evenly arranged along the X-axis direction and the Y-axis direction.

Here, in the sensor array 10A constituting the ultrasonic sensor, the substrate 11 and the support film 14 of each sensor body 10 are common members, and the support film 14 is formed on one substrate 11, and the support film 14 is formed on the support film 14. As shown in FIG. 9, each sensor main body 10 divided into rectangular sections is formed.
And between the sensor bodies 10 adjacent to each other in the sensor array 10A, a proximity detecting ultrasonic element 40 is provided as shown in FIG.

  The proximity detecting ultrasonic element 40 includes an opening 111 formed in the substrate 11, a support film 14 (membrane 141) that closes the opening 111, and a piezoelectric film on a film disposed in the inner region of the membrane 141. 41, and a lower electrode 42 and an upper electrode 43 arranged with the piezoelectric film 41 interposed therebetween. Further, the elastic film 15 is not formed on the proximity detecting ultrasonic element 40. Therefore, when an AC voltage is applied to the proximity detection ultrasonic element 40, the ultrasonic wave is transmitted by propagating air directly above the sensor array 10A.

Here, the piezoelectric film 41, the lower electrode 42, and the upper electrode 43 are made of the same material as the piezoelectric film 21, the lower electrode 22, and the upper electrode 23 that constitute the ultrasonic element 20. Further, in the sensor plan view, the opening 111 and the membrane 141 of the proximity detecting ultrasonic element 40 are formed to have a larger area than the opening 111 and the membrane 141 of the ultrasonic element 20, and the piezoelectric film 41, the lower electrode, and the like. 42 and the upper electrode 43 also have larger areas than the piezoelectric film 21, the lower electrode 22, and the upper electrode 23. As a result, the proximity detecting ultrasonic element 40 can output ultrasonic waves having a higher sound pressure than the ultrasonic element 20 and can transmit ultrasonic waves to a farther distance.
In such a tactile sensor 1A, when the contact object L approaches immediately above the sensor array 10A, the ultrasonic wave transmitted from the proximity detection ultrasonic element 40 is reflected by the contact object L, and the proximity detection ultrasonic element 40 is detected. Received at.

  In FIG. 9, the configuration in which the elastic film 15 is separated for each sensor body 10 is illustrated, but the configuration is not limited thereto, and for example, a configuration in which the elastic film 15 covering the entire support film 14 may be provided. In this case, the elastic film 15 may be provided with an opening only in the region immediately above the proximity detecting ultrasonic element 40, and a distance detecting ultrasonic wave may be transmitted from the opening.

FIG. 11 is a block diagram illustrating a schematic configuration of the control unit 30A in the tactile sensor 1A.
As shown in FIG. 11, the control unit 30A includes a distance calculation unit 373 in addition to the components of the first and second embodiments.
When the time measurement unit 35 acquires TOF data based on the reception signal output from the proximity detection ultrasonic element 40, the distance calculation unit 373 and the sensor array 10A and the contact object are acquired based on the TOF data. The distance from L is calculated. Specifically, the speed of sound in the air is stored in advance in the storage unit 36 of the control unit 30A, and the time measurement unit 35 is based on the acquired TOF data and the speed of sound in the air read from the storage unit 36. Thus, the distance between the sensor array 10A and the contact L is calculated.

  The transmission / reception switching control unit 33 of the control unit 30A sets the tactile sensor 1A to the standby mode when the power of the tactile sensor 1A is turned on. In this standby state, the transmission / reception switching control unit 33 stops the ultrasonic element 20 and drives only the proximity detecting ultrasonic element 40. That is, the transmission / reception switching control unit 33 periodically transmits an ultrasonic transmission mode in which ultrasonic waves are transmitted from the proximity detection ultrasonic element 40 and ultrasonic reception in which reflected ultrasonic waves are received by the proximity detection ultrasonic element 40. Switch to mode. In the ultrasonic wave transmission mode of the proximity detection ultrasonic element 40, the ultrasonic signal transmission circuit 34 sets a drive voltage larger than the drive voltage for driving the ultrasonic element 20 and outputs it as a drive signal.

When the time measurement unit 35 acquires TOF data based on the reception signal output from the proximity detection ultrasonic element 40, the transmission / reception switching control unit 33 contacts the sensor array 10A calculated by the distance calculation unit 373. The distance to the object L is monitored. When the transmission / reception switching control unit 33 determines that the distance between the sensor array 10A and the contact object L is equal to or less than a preset threshold value, the transmission / reception switching control unit 33 sets the driving mode. In this drive mode, as in the first and second embodiments, an ultrasonic wave transmission mode in which ultrasonic waves are periodically transmitted from the ultrasonic element 20 and an ultrasonic wave in which reflected ultrasonic waves are received by the ultrasonic element 20 are used. Switch to sound wave reception mode. Thereby, control part 30A performs the process which calculates the stress which acts on the elastic film 15 when the contact thing L contacts the elastic film 15, like said 1st and 2nd embodiment. At this time, the transmission / reception switching control unit 33 stops driving the proximity detecting ultrasonic element 40.
When the transmission / reception switching control unit 33 determines that the stress (positive pressure and shearing force) calculated by the stress calculation unit 372 has become “0”, the transmission / reception switching control unit 33 shifts to the standby mode again and stops the ultrasonic element 20. Then, the proximity detecting ultrasonic element 40 is driven.

[Operational effects of the third embodiment]
In the tactile sensor 1A of the third embodiment, in addition to the operational effects of the first embodiment, the following effects can be achieved. That is, the tactile sensor 1A includes a sensor array 10A in which a plurality of sensor bodies 10 are arranged in an array. For this reason, it is possible to detect the positive pressure and the shearing force over a wide range by the plurality of sensor bodies 10.

In addition, a proximity detection ultrasonic element 40 is provided between adjacent sensor bodies 10. For this reason, it is determined whether or not the ultrasonic wave transmitted from the proximity detecting ultrasonic element 40 is reflected by the contact object L and returned, thereby determining whether or not the contact object L exists in the vicinity of the tactile sensor 1A. Can be determined.
Furthermore, since the distance calculation unit 373 is provided in the control unit 30A, the contact object L from the sensor array 10A is measured using the TOF data measured based on the reception data output from the proximity detection ultrasonic element 40. Can be calculated.

  Further, the transmission / reception switching control unit 33 stops the driving of the ultrasonic element 20 when the distance to the contact object L calculated by the distance calculation unit 373 is equal to or greater than a preset threshold value, and until the contact object L is reached. When the distance becomes smaller than a preset threshold, the ultrasonic element 20 is driven. Thus, power saving can be achieved by switching the driving of the ultrasonic element 20.

[Fourth embodiment]
Next, as an application example of the apparatus using the touch sensor 1 or 1A described above, a gripping apparatus including the touch sensor 1A will be described with reference to the drawings.

FIG. 12 is an apparatus block diagram showing a schematic configuration of a gripping apparatus according to a fourth embodiment of the present invention.
In FIG. 12, a gripping device 50 is a device that includes at least a pair of gripping arms 51 and grips a contact object L (a gripping target object) with the gripping arms 51. The gripping device 50 is a device that grips and lifts an object conveyed by a belt conveyor or the like, for example, in a manufacturing factory that manufactures products. The gripping device 50 includes the gripping arm 51, an arm driving unit 52 that drives the gripping arm 51, and a control device 54 that controls the driving of the arm driving unit 52.

  Each of the pair of gripping arms 51 includes a gripping surface 53 that is a contact surface at the tip, and grips and lifts the contact object L by holding the gripping surface 53 in contact with the contact object L. Here, in the present embodiment, a configuration in which a pair of gripping arms 51 is provided is illustrated, but the present invention is not limited to this. For example, a configuration in which the gripping object L is gripped by three-point support by the three gripping arms 51 may be used. Good.

  The grip surface 53 provided on the grip arm 51 is provided with the touch sensor 1A described in the third embodiment on the surface, and the elastic film 15 on the surface portion of the touch sensor 1A is exposed. The gripping arm 51 grips the contact object L by bringing the elastic film 15 into contact with the contact object L and applying a predetermined pressure (positive pressure) to the contact object L. In such a grip arm 51, the tactile sensor 1 </ b> A provided on the grip surface 53 detects a positive pressure applied to the contact object L and a shearing force that the contact object L tries to slide down from the grip surface 53 when gripped. Then, an electrical signal corresponding to the positive pressure and shearing force is output to the control device 54.

The arm drive unit 52 is a device that moves the pair of gripping arms 51 in a direction in which they are close to and away from each other. The arm driving unit 52 includes a holding member 55 that holds the gripping arm 51 movably, a drive source 56 that generates a driving force that moves the gripping arm 51, and a driving force of the driving source that is transmitted to the gripping arm 51. A drive transmission unit 57 is provided.
The holding member 55 includes, for example, a guide groove along the moving direction of the grip arm 51, and holds the grip arm 51 in a movable manner by holding the grip arm 51 in the guide groove. The holding member 55 is provided so as to be movable in the vertical direction.
The drive source 56 is, for example, a drive motor, and generates a driving force in accordance with a drive control signal input from the control device 54.
The drive transmission unit 57 is configured by, for example, a plurality of gears, transmits the driving force generated by the drive source 56 to the grip arm 51 and the holding member 55, and moves the grip arm 51 and the holding member 55.
In the present embodiment, the above configuration is shown as an example, but the present invention is not limited to this. That is, the configuration is not limited to the configuration in which the grip arm 51 is moved along the guide groove of the holding member 55, and the configuration may be such that the grip arm is rotatably held. The drive source 56 is not limited to a drive motor, and may be configured to be driven by, for example, a hydraulic pump. The drive transmission unit 57 is not limited to a configuration in which a drive force is transmitted by a gear, but is transmitted by a belt or a chain. It is good also as a structure provided with the piston driven by a structure, hydraulic pressure, etc.

The control device 54 is connected to the tactile sensor 1 </ b> A provided on the gripping surface 53 of the gripping arm 51 and the arm driving unit 52, and controls the entire gripping operation of the contact object L in the gripping device 50.
Specifically, as shown in FIG. 12, the control device 54 is connected to the arm driving unit 52 and the tactile sensor 1 </ b> A, and controls the entire operation of the gripping device 50. The control device 54 includes a signal detection unit 541 that reads a shearing force detection signal and a positive pressure detection signal input from the tactile sensor 1A, a gripping detection unit 542 that detects a sliding state of the contact object L, and an arm driving unit 52. Drive control means 543 for outputting a drive control signal for controlling the drive of the gripping arm 51 is provided. Moreover, as this control apparatus 54, general purpose computers, such as a personal computer, can also be used, for example, it is good also as a structure provided with the display part etc. which display input devices, such as a keyboard, and the holding state of the contact thing L, for example.
The signal detection unit 541, the grip detection unit 542, and the drive control unit 543 may be stored in a storage unit such as a memory as a program, and may be appropriately read and executed by an arithmetic circuit such as a CPU. For example, it may be constituted by an integrated circuit such as an IC and perform predetermined processing on the input electric signal.

  The signal detection unit 541 is connected to the tactile sensor 1A, and acquires a positive pressure detection signal, a shear force detection signal, and the like input from the tactile sensor 1A. The detection signal recognized by the signal detection unit 541 is output to and stored in a storage unit such as a memory (not shown), and is output to the grip detection unit 542.

The grip detection unit 542 determines whether the contact object L is gripped by the grip arm 51 based on the shearing force detection signal.
Here, FIG. 13 shows a diagram showing the relationship between the positive pressure and the shearing force acting on the tactile sensor in the gripping operation of the gripping device 50.
In FIG. 13, until the positive pressure reaches a predetermined value, the shearing force increases as the positive pressure increases. This state is a state in which a dynamic frictional force is acting between the contact object L and the gripping surface 53, and the gripping detection means 542 is in a slipping state where the contact object L has slipped off the gripping surface 53, and gripping is not performed. Judged to be incomplete. On the other hand, when the positive pressure exceeds a predetermined value, the shear force does not increase even if the positive pressure is increased. This state is a state in which a static frictional force is acting between the contact object L and the gripping surface 53, and the grip detection unit 542 determines that the contact object L is gripped by the gripping surface 53. .
Specifically, when the value of the shearing force detection signal exceeds a predetermined threshold corresponding to the static friction force, it is determined that the gripping has been completed.

  The drive control unit 543 controls the operation of the arm drive unit 52 based on the electrical signal detected by the grip detection unit 542.

Next, operation | movement of the control apparatus 54 is demonstrated based on drawing.
FIG. 14 is a flowchart showing a gripping operation of the gripping device 50 under the control of the control device 54. FIG. 15 is a timing chart showing the transmission timing of the drive control signal to the arm drive unit 52 and the detection signal output from the tactile sensor 1A during the gripping operation of the gripping device 50.

  In order to grip the contact object L with the gripping device 50, first, the drive control means 543 of the control device 54 outputs a drive control signal to the arm drive unit 52 to move the gripping arms 51 in the direction of approaching each other. (Gripping operation). As a result, the gripping surface 53 of the gripping arm 51 approaches the contact object L (FIG. 14: Step S11).

  Next, the grip detection unit 542 of the control device 54 determines whether or not the contact object L has contacted the grip surface 53 (FIG. 14: Step S12). Specifically, the control device 54 determines whether or not an input of a positive pressure detection signal is detected by the signal detection unit 541. Here, when the positive pressure detection signal is not detected, it is determined that the gripping surface 53 is not in contact with the contact object L, and the drive control unit 543 continues the step S11 to output the drive control signal and perform gripping. The arm 51 is further driven.

On the other hand, when the gripping surface 53 comes into contact with the contact object L (FIG. 15: timing T1), the elastic film 15 of the tactile sensor 1A is distorted, and a positive pressure detection signal corresponding to the positive pressure calculated based on the amount of distortion is generated. Is output.
When the grip detection unit 542 detects a positive pressure detection signal, the drive control unit 543 stops the proximity movement (pressing on the contact object L) of the grip arm 51 (FIG. 14: step S13, FIG. 15: timing T2). . Further, the drive control means 543 outputs a drive control signal to the arm drive unit 52 to perform an operation (lifting operation) for lifting the grip arm 51 upward (FIG. 14: step S14, FIG. 15: timings T2 to T3). .

Here, when the contact object L is lifted, the elastic film 15 is distorted in the shearing direction by the shearing force, and the tactile sensor 1A calculates a shearing force corresponding to the amount of strain, and a shearing force detection signal corresponding to the shearing force. Is output.
The grip detection unit 542 determines whether or not there is a slip based on the shearing force detection signal input to the signal detection unit 541 (step S15).

At this time, if it is determined by the grip detection means 542 that there is a slip, the drive control means 543 controls the arm drive unit 52 to move the grip arm 51 in a direction to press the grip surface 53 against the contact object L. Thus, the gripping force (positive pressure) is increased (FIG. 14: Step S16).
That is, the control device 54 causes the drive control means 543 to perform a gripping operation at a timing T3 in FIG. 15 to increase the positive pressure on the contact object L, and the signal detection means 541 outputs again from the touch sensor 1A. The detected shear force detection signal is detected. When the slip detection operation (timing T2 to T6) as described above is repeated and the shearing force detection signal is equal to or greater than a predetermined threshold value S1 (timing T6), there is no slip, that is, gripping is completed in step S15. The slip detection operation is stopped.

[Effects of Fourth Embodiment]
The gripping device 50 according to the fourth embodiment as described above includes the tactile sensor 1A according to the third embodiment. As described above, the tactile sensor 1A can easily and accurately detect the shearing force and the positive pressure at an arbitrary position. Therefore, the gripping device 50 can accurately detect the shearing force detection signal and the positive pressure. An accurate gripping operation can be performed based on the pressure detection signal.
Moreover, with such a tactile sensor 1A, it is possible to detect a shearing force in both the X-axis direction and the Y-axis direction. Therefore, in the fourth embodiment, the shearing force when lifting the contact object L is measured. However, for example, when the object to be transported on the belt conveyor is gripped, the shearing force in the transporting direction is also measured. Can be measured.

[Fifth embodiment]
In the fourth embodiment, the gripping device provided with the tactile sensor 1A is exemplified as an example of a device including the tactile sensor. However, the present invention is not limited to this.
In the fifth embodiment, an iron provided with a touch sensor 1A will be described with reference to the drawings as another application example of an apparatus using the touch sensors 1 and 1A.
FIG. 16 is a block diagram showing a schematic configuration of the iron of the fifth embodiment.

  The iron 60 includes a heater 61, a base portion 62, a temperature sensor 63 provided on the base portion 62, a tactile sensor 1 </ b> A provided on the base portion 62, and a heater drive circuit 64. The heater drive circuit 64 of the iron 60 controls the voltage applied to the heater 61 based on signals from the temperature sensor 63 and the tactile sensor 1A, and heats the base portion 62 to an optimum temperature for the target fabric.

The heater 61 generates heat by the voltage applied from the heater drive circuit 64 and heats the base portion 62.
The base portion 62 is a portion that comes into contact with the target fabric and stretches the wrinkles of the target fabric, and is heated by the heater 61. Then, as shown in FIG. 16, a touch sensor 1 </ b> A is provided on a part of the base portion 62, and the elastic film 15 of the touch sensor 1 </ b> A is exposed so as to be in contact with the target fabric.
The base unit 62 is provided with a temperature sensor 63, and this temperature sensor 63 detects the temperature of the base unit 62 and outputs it to the heater drive circuit 64.

The heater driving circuit 64 is connected to the tactile sensor 1A, the temperature sensor 63, and the heater 61, and controls the voltage applied to the heater 61 based on signals from the tactile sensor 1A and the temperature sensor 63. As shown in FIG. 16, the heater drive circuit 64 includes a memory 641 that is a storage unit of the present invention, a signal detection unit 642, a fabric determination unit 643, and a temperature control unit 644.
The heater drive circuit 64 is configured, for example, as a computer having a calculation circuit such as a CPU or a storage circuit, and the fabric determination unit 643 and the temperature control unit 644 function as software executed by calculation processing by the calculation circuit. For example, an integrated circuit such as an IC may be used, and a predetermined process may be performed on the input electric signal.

The memory 641 stores stress-roughness value data that is correlation data of the present invention. The stress-roughness value data is data in which the roughness value of the target fabric is recorded in accordance with the stress detected by the tactile sensor 1A. For example, the roughness value corresponding to the shearing force is correct. Recorded for each pressure.
The memory 641 may store roughness-temperature data in which the optimum temperature of the base unit 62 corresponding to the roughness value is recorded.

  The signal detection unit 642 is connected to the touch sensor 1A, and acquires a positive pressure detection signal, a shear force detection signal, and the like input from the touch sensor 1A. The detection signal detected by the signal detection unit 642 is output and stored in the memory 641 and also output to the fabric discrimination unit 643.

The fabric discrimination unit 643 discriminates the type of the target fabric based on the shearing force and positive pressure input from the signal detection unit 642 and the stress-roughness value data stored in the memory 641.
For example, in this embodiment, the roughness corresponding to the shearing force is stored for each positive pressure as the stress-roughness value data. In this case, the fabric discriminating unit 643 reads out the stress-roughness value data corresponding to the positive pressure from the memory 641 and acquires the roughness value corresponding to the shearing force from the stress-roughness value data.
Then, the fabric discrimination unit 643 outputs the acquired roughness value to the temperature control unit 644.

The temperature control unit 644 controls the voltage applied to the heater 61 based on the roughness value input from the fabric determination unit 643 and the temperature of the base unit 62 detected by the temperature sensor 63.
Specifically, the temperature control unit 644 reads roughness-temperature data from the memory 641 and acquires the optimum temperature of the base unit 62 according to the roughness value input from the fabric determination unit 643. Then, the temperature control unit 644 calculates an applied voltage value to the heater 61 necessary for setting the base unit 62 to the optimum temperature from the difference value between the detected temperature and the optimum temperature input from the temperature sensor 63. Apply to heater 61.

[Iron operation]
Next, the operation of the iron 60 as described above will be described.
FIG. 17 is a flowchart showing the operation of the iron according to the fifth embodiment.
When power is supplied to the iron 60 by the user, the proximity detecting ultrasonic element 40 of the tactile sensor 1A is driven. Accordingly, as described in the third embodiment, the touch sensor 1A calculates the distance between the target fabric and the touch sensor 1A (base portion 62). When the distance between the target fabric and the base portion 62 is within a preset distance, the touch sensor 1A shifts to the drive mode (step S21).

  Thereafter, the heater drive circuit 64 of the iron 60 determines whether or not the target fabric has contacted the base portion 62 (step S22). Specifically, the heater drive circuit 64 determines whether or not the signal detection unit 642 detects the input of a positive pressure detection signal. Here, when the positive pressure detection signal is not detected, it is determined that the target fabric is not in contact with the base portion 62. In this case, the heater drive circuit 64 continues step S22 and continues the contact determination process between the target fabric and the base portion 62.

In step S22, when the signal detection unit 642 detects the input of the positive pressure detection signal, the signal detection unit 642 further detects the input of the shear force detection signal and determines whether the magnitude of the shear force is greater than zero ( Step S23).
That is, since the magnitude of the positive pressure changes depending on the strength with which the user presses the iron 60 against the target fabric, the type of the target fabric cannot be determined only by the positive pressure. Therefore, when the magnitude of the shearing force is 0, the process of step S23 is continued.
On the other hand, when the magnitude of the shearing force detected by the shearing force detection signal is greater than 0 in step S23, the fabric determination unit 643 reads the stress-roughness value data corresponding to the positive pressure from the memory 641, and shears. A roughness value corresponding to the force is acquired (step S24).

Thereafter, the temperature control unit 644 reads the roughness-temperature data from the memory 641, acquires the temperature corresponding to the roughness value acquired in step S24, and sets it as the optimum temperature (step S25).
Furthermore, the temperature control unit 644 applies the difference between the detected temperature detected by the temperature sensor 63 and the optimum temperature set in step S25 to the heater 61 necessary for setting the base unit 62 to the optimum temperature. An applied voltage value is calculated, and the voltage value is applied to the heater 61 (step S26).
Thereby, the iron 60 can automatically set the temperature of the base portion 62 according to the type of the target fabric.

[Effects of Fifth Embodiment]
The iron 60 of the fifth embodiment as described above includes the touch sensor 1A of the third embodiment. As described above, the tactile sensor 1A can easily and accurately detect the shearing force and the positive pressure at an arbitrary position. Therefore, even in the iron 60, the target fabric is in contact with the base portion 62. The positive pressure and shear force at the time can be detected with high accuracy.

  And the heater drive circuit 64 of the iron 60 can discriminate the roughness of the target fabric corresponding to the detected positive pressure and shearing force by the fabric discriminating unit 643. Therefore, the type of the target fabric can be determined from the determined roughness of the target fabric, and the temperature control unit 644 can set the temperature of the base unit 62 corresponding to the type of the fabric. Therefore, in the iron 60, the temperature of the base part 62 can be automatically set corresponding to the fabric, and the complicated work of changing the temperature setting according to the type of the target fabric can be omitted.

In the fifth embodiment, an example in which the stress-roughness data in which the roughness value corresponding to the positive pressure and the shearing force is recorded is stored in the memory 641 is described. However, for example, the positive pressure and the shearing force are stored. The memory 641 may be configured to store the stress-fabric type data in which the type of the target fabric corresponding to the data is recorded. In this case, the fabric determination unit 643 directly determines the type of the target fabric according to the positive pressure and the shearing force, and the temperature control unit 644 acquires a temperature corresponding to the determined type of fabric.
Further, as the correlation data, stress-temperature data in which the optimum temperature of the base portion 62 corresponding to the positive pressure and the shearing force is stored may be stored. In this case, it is necessary to store the roughness-temperature data. Thus, it is possible to provide the iron 60 capable of automatically setting the temperature of the base portion 62 with a smaller amount of data.

  Further, in the iron 60, an example in which the temperature of the base portion 62 is automatically set by the heater driving circuit 64 has been shown. However, for example, an automatic mode in which the temperature of the base portion 62 is automatically set and a temperature is set manually. It is good also as a structure which can be switched to manual mode suitably.

[Other Embodiments]
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  For example, in the above embodiment, the tactile sensors 1 and 1A provided with the regular quadrangular pyramid-shaped ultrasonic reflector 16 are illustrated, but the present invention is not limited to this, and may be formed in a spherical shape or a truncated cone shape, for example. May be. However, in this case, as described above, since the reflection position of the ultrasonic wave becomes narrow and the reception signal becomes small, for example, it is necessary to increase the output value of the ultrasonic wave or separately provide an amplification circuit for amplifying the reception signal. is there.

Further, by using a regular quadrangular pyramid shaped ultrasonic reflector 16, the shear force along the X-axis direction and the Y-axis direction perpendicular to the X-axis direction can be detected. A cross-sectional shape obtained by cross-sectioning the body 16 in a direction orthogonal to the thickness of the elastic film 15 may be a rhombus shape. In this case, the shear force acting on the X-axis direction and the Y′-axis direction intersecting the X-axis direction can be calculated.
In addition, when the direction of the shearing force to be detected is predetermined and the direction is only one direction, an ultrasonic reflector having two element facing surfaces and two ultrasonic waves facing each element facing surface It is only necessary to provide an element, and the configuration can be simplified.
Furthermore, when the direction of the shearing force to be detected is determined in advance and there are three or more directions, a polygonal frustum-shaped ultrasonic reflector having a pair of element facing surfaces in each of these directions. May be used.

  In the above embodiment, the ultrasonic reflector 16 is provided with the fifth element facing surface 161E at the top, and the substrate 11 is provided with the fifth ultrasonic element 20E facing the fifth element facing surface 161E. Although the configuration is adopted, a configuration in which the fifth element facing surface 161E and the fifth ultrasonic element 20E are not provided, for example, a quadrangular pyramid shaped ultrasonic reflector may be used. In such a configuration, as described above, the positive pressure is calculated based on the TOF data acquired by the first to fourth element facing surfaces 161A to 161D and the first to fourth ultrasonic elements 20A to 20D. The configuration can be further simplified because the fifth ultrasonic element 20E is not provided. Further, by adopting a configuration in which the fifth element facing surface 161E is not provided on the ultrasonic reflector 16, the volume of the ultrasonic reflector 16 can be reduced, and the tactile sensors 1 and 1A can be reduced in size. .

  Further, in the tactile sensors 1 and 1A of the first to fourth embodiments, the configuration in which ultrasonic waves that diffuse radially from one ultrasonic element 20 are illustrated, but for example, instead of each ultrasonic element 20 An ultrasonic array in which a plurality of ultrasonic elements are arranged in an array may be arranged. In such an ultrasonic array, by delaying the timing of transmitting ultrasonic waves from each ultrasonic element, it becomes possible to transmit beam-shaped ultrasonic waves that propagate as plane waves in a desired direction. Therefore, ultrasonic waves may be transmitted from the respective ultrasonic arrays toward the element facing surfaces corresponding to these ultrasonic arrays. In such a configuration, when the elastic film 15 is largely distorted and the ultrasonic reflector 16 is largely displaced, it is necessary to adjust the driving timing of each ultrasonic element and adjust the ultrasonic wave transmission angle appropriately. Since ultrasonic waves transmitted from a plurality of ultrasonic elements strengthen each other, a high sound pressure ultrasonic wave can be transmitted. For this reason, each ultrasonic array can receive a large reflected ultrasonic wave, and the signal detection accuracy can be improved. In addition, since ultrasonic waves having a high sound pressure can be transmitted, even when a spherical reflector or a truncated cone is used as the ultrasonic reflector 16, a reflected ultrasonic wave having a relatively large sound pressure is received. Can do.

  In the third embodiment, each sensor body 10 arranged in the sensor array 10A is configured such that the substrate 11 and the support film 14 are common members. For example, the substrate 11 and the support film are provided for each sensor body 10. 14 may be provided. In this case, for example, a sensor mounting substrate may be prepared separately, and the sensor array may be configured by arranging the sensor main bodies 10 in an array on the sensor mounting substrate.

  Further, in the fourth embodiment, the configuration in which the pair of gripping arms 51 is provided as the gripping device 50 is illustrated, but the configuration in which the contact object L is gripped by moving three or more gripping arms in the direction of approaching and separating from each other. It is good. Moreover, it is good also as a structure etc. which are provided with the drive arm driven by an arm drive part, and the fixed arm or fixed wall which is not driven, and moves a drive arm to the fixed arm (fixed wall) side.

Further, in the fourth embodiment, an example in which the tactile sensor 1A is applied to the gripping device 50 that grips the contact object L is shown. In the fifth embodiment, the iron 60 provided with the tactile sensor 1A is illustrated. It is not limited to. For example, the touch sensor 1A may be applied as an input device, for example. When used as an input device, it can be incorporated into, for example, a notebook personal computer or a personal computer. Specifically, the structure etc. which provide the tactile sensor 1A in the surface part provided in a plate-shaped input device main body can be illustrated. In such an input device, when a user's finger is moved on the surface portion or a touch pen is moved, shearing force and positive pressure are generated by these movements. By detecting this shearing force and positive pressure with the tactile sensor 1A, it is possible to detect the contact position coordinates and the moving direction of the user's finger or touch pen and output them as electrical signals.
Moreover, although the cloth discrimination | determination part 643 which discriminate | determines the classification (roughness value) of a fabric based on the stress-roughness data memorize | stored in the memory 641 was illustrated as a contact thing discrimination | determination part, it is not restricted to this. For example, the tactile sensors 1 and 1A may be provided in the bread manufacturing apparatus, and a contact object determining unit that determines the softness (kneading state) of the bread dough may be provided. In this case, the contact part determination part stores in the memory the relationship data between the stress applied to the bread dough and the optimum elastic force against the stress. Then, the contact object determination unit determines that the kneading state is optimal when the positive pressure and shearing force detected by the tactile sensors 1 and 1A are within a predetermined threshold value centered on the optimal elastic force. In the bread manufacturing apparatus having such a configuration, the kneaded state of the dough can be kept constant, and a stable quality dough can be manufactured.

In each of the above embodiments, the tactile sensors 1 and 1A in which a plurality of ultrasonic elements 20 are arranged on the substrate 11 are exemplified, but the present invention is not limited to this. That is, the ultrasonic element 20 may be disposed above the substrate 11. For example, an intermediate layer may be stacked on the substrate 11 and the ultrasonic element 20 may be disposed thereon.
Alternatively, a configuration may be adopted in which a protective film having the same acoustic impedance as the elastic film 15 is laminated on the ultrasonic element 20 and the elastic film 15 is laminated on the protective film.

  Although the best configuration for carrying out the present invention has been specifically described above, the present invention is not limited to this. That is, the present invention has been illustrated and described primarily with respect to particular embodiments, but the present invention is not limited to the embodiments described above without departing from the scope of the technical idea and object of the present invention. Various modifications and improvements can be made by a trader.

  DESCRIPTION OF SYMBOLS 1,1A ... Tactile sensor, 10 ... Sensor main body, 11 ... Board | substrate, 15 ... Elastic film, 16 ... Ultrasonic reflector, 20 ... Ultrasonic element, 20A ... First ultrasonic element, 20B ... Second ultrasonic element, 20C: Third ultrasonic element, 20D: Fourth ultrasonic element, 20E: Fifth ultrasonic element, 30, 30A: Control unit, 31: Element switching circuit constituting ultrasonic transmission control unit, 32: Ultrasonic transmission Transmission / reception switching circuit constituting the control unit, 33... Transmission / reception switching control unit constituting the ultrasonic transmission control unit, 34... Ultrasonic signal transmission circuit constituting the ultrasonic transmission control unit, 35. Ultrasonic element 50 ... gripping device 51 ... gripping arm 53 ... gripping surface which is a contact surface 161 ... element facing surface 161A ... first element facing surface 161B ... second element facing surface 161C ... third Element facing surface, 161D ... fourth element Opposing surface, 161E... Fifth element facing surface which is the top, 371... Movement amount calculating unit, 372... Stress calculating unit, 542 .. grip detection means, 543... Drive control means, 641. Cloth discrimination part which comprises a contact thing discrimination | determination part, L ... contact thing.

Claims (13)

A substrate,
A plurality of ultrasonic elements provided on the substrate;
An elastically deformable elastic film disposed on the plurality of ultrasonic elements;
An ultrasonic reflector provided inside the elastic film and capable of reflecting ultrasonic waves;
With
The ultrasonic reflector, said element surface facing the ultrasonic element, a plurality of perforated in correspondence to each of the plurality of ultrasonic elements,
When an axis along the surface of the substrate is an X axis, a direction perpendicular to the X axis along the surface of the substrate is a Y axis, and a direction perpendicular to the X axis and the Y axis is a Z axis,
The ultrasonic reflector is
A top located closest to the substrate;
A first element facing surface provided continuously from the top in the + X direction on the X axis;
A second element facing surface provided continuously from the top in the -X direction on the X axis;
Have
The first element facing surface is a plane defined by a straight line parallel to the Y-axis and a straight line inclined at a first inclination angle that moves away from the substrate toward the + X direction on the XZ plane,
The second element facing surface is a plane defined by a straight line parallel to the Y-axis and a straight line inclined at a second inclination angle that moves away from the substrate toward the −X direction on the XZ plane,
A first ultrasonic element facing the first element facing surface and a second ultrasonic element facing the second element facing surface are disposed along the X-axis on the substrate. Ultrasonic sensor. The ultrasonic sensor according to claim 1 ,
The ultrasonic sensor, wherein the first inclination angle and the second inclination angle are 45 degrees with respect to the X axis. The ultrasonic sensor according to claim 1 or 2 ,
The ultrasonic reflector is
A third element facing surface provided continuously from the top in the + Y direction on the Y axis;
A fourth element facing surface provided continuously from the top in the -Y direction on the Y axis;
Have
The third element facing surface is a plane defined by a straight line parallel to the X-axis and a straight line inclined at a third inclination angle that moves away from the substrate toward the + Y direction on the YZ plane,
The fourth element facing surface is a plane defined by a straight line that is parallel to the X axis and a straight line that is inclined at a fourth inclination angle away from the substrate as it goes in the -Y direction on the YZ plane,
A third ultrasonic element facing the third element facing surface and a fourth ultrasonic element facing the fourth element facing surface are arranged along the Y axis on the substrate. Ultrasonic sensor. The ultrasonic sensor according to claim 3 .
The ultrasonic sensor, wherein the third inclination angle and the fourth inclination angle are 45 degrees with respect to the Y axis. The ultrasonic sensor according to any one of claims 1 to 4 ,
The top is a fifth element facing surface parallel to the surface of the substrate;
An ultrasonic sensor, wherein a fifth ultrasonic element facing the fifth element facing surface is disposed on the substrate. The ultrasonic sensor according to claim 5 ,
The ultrasonic reflector has a quadrangular frustum shape. The ultrasonic sensor according to any one of claims 1 to 6 ,
On the substrate,
A plurality of sensor bodies configured by the elastic film, the ultrasonic reflector, and a plurality of the ultrasonic elements facing the plurality of element facing surfaces of the ultrasonic reflector are arranged in a plurality of arrays. Ultrasonic sensor to do. The ultrasonic sensor according to claim 7 ,
A proximity detection ultrasonic element for transmitting ultrasonic waves in the air and receiving ultrasonic waves reflected by a contact object is provided between adjacent sensor bodies on the substrate. Ultrasonic sensor to do. The ultrasonic sensor according to any one of claims 1 to 8 ,
A control unit that controls transmission and reception of ultrasonic waves of each ultrasonic element of the ultrasonic sensor;
A tactile sensor characterized by comprising: In the tactile sensor according to claim 9 ,
The controller is
An ultrasonic transmission control unit for transmitting ultrasonic waves from the ultrasonic element;
A time measuring unit for measuring a time from an ultrasonic wave transmission timing of the ultrasonic element to a reception timing at which the ultrasonic wave reflected by the ultrasonic reflector is received by the ultrasonic element;
Based on the time measured by the time measuring unit, a moving amount calculating unit that calculates a moving amount and a moving direction of the ultrasonic reflector,
A tactile sensor characterized by comprising: The tactile sensor according to claim 10 ,
The controller is
A stress calculating unit that calculates a stress acting on the elastic film based on the moving amount and moving direction of the ultrasonic reflector calculated by the moving amount calculating unit and the Young's modulus of the elastic film; Features tactile sensor. The tactile sensor according to claim 11 .
The ultrasonic sensor is configured such that the elastic film, the ultrasonic reflector, and a plurality of the ultrasonic elements facing the element facing surfaces of the ultrasonic reflector are arranged on the substrate. A plurality of sensor bodies are provided, and the plurality of sensor bodies are arranged in an array.
The tactile sensor
A storage unit for storing correlation data in which a state of a contact object in contact with the elastic film is recorded with respect to stress acting on the elastic film;
A contact object determination unit that determines the state of the contact object based on the stress calculated by the stress calculation unit and the correlation data;
A tactile sensor characterized by comprising: A gripping device comprising the tactile sensor according to any one of claims 9 to 12 , and gripping an object,
At least a pair of gripping arms that grips the object and is provided with the tactile sensor on a contact surface that contacts the object;
Grip detection means for detecting a slip state of the object based on a signal output from the tactile sensor;
Drive control means for controlling the drive of the gripping arm based on the sliding state;
A gripping device comprising: