JP2013108832A - Detecting device, electronic apparatus, and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting device capable of detecting composite information that contains force sensing information indicating a direction and size of external force applied to an object, and slip sensing information indicating a standstill or slippage of the object to which an external force is applied.SOLUTION: A detecting device 100 has a detecting section K and a calculating section E, the detecting section K including an elastic substrate A, a slip detecting section B, a rigid substrate C, and an external force detecting section D, which are laminated on one another in this order starting from the side on which the external force is applied, the slip detecting section B having a pressure-sensitive conductive sheet and a pair of electrodes for detecting a resistance value of the pressure-sensitive conductive sheet, and the external force detecting section D including a first substrate which has a plurality of pressure sensors arranged around a base point, and a second substrate on which an elastic projection is formed that elastically deforms in a state where a tip abuts on the first substrate when an external force is applied. The detecting device 100 can detect slip sensing information indicating a standstill or slippage of the object by using the slip detecting section B, and force sensing information indicating a direction and magnification of the applied external force by using the external force detecting section D, at the same time.

Description

  The present invention relates to a detection device, an electronic device, and a robot.

As a detection device for detecting an external force, detection devices described in Patent Documents 1 and 2 are known. Application of such a detection apparatus to a touch panel, a tactile sensor of a robot, or the like is being studied.
The detection device of Patent Document 1 is configured to detect a pressure distribution from a deformation amount of a protrusion using a pressure-receiving sheet in which weight-like protrusions are substantially uniformly arranged on the back surface. The detection device of Patent Document 2 has a configuration in which a plurality of columnar protrusions are arranged in a matrix on the surface of a pressure-receiving sheet, and a conical protrusion is provided on the back surface of a portion obtained by equally dividing the periphery of these surface protrusions. .

Japanese Patent Laid-Open No. 60-135834 JP-A-7-128163

However, the detection device of Patent Document 1 cannot measure the in-plane force (sliding force) of the pressure applied to the measurement surface. In the detection device of Patent Document 2, it is possible to detect an external force as a three-dimensional force vector, but the detection limit of the external force is determined by the degree of deformation of the protrusion.
As described above, the detection devices of Patent Documents 1 and 2 both have a problem that the direction and magnitude of the external force cannot be detected with high accuracy.

  Furthermore, in recent robots, not only the operation of gripping a hard object, but also the operation of gripping a soft object with an appropriate force, for example, the operation of stroking, rubbing, wiping, etc., closer to humans Operating performance is required. In order to realize such a robot, it is necessary to detect tactile (force / slip) information in a sensory function of a person with high accuracy. Specifically, in addition to the haptic information on the direction and magnitude of the force acting on the object (hereinafter referred to as external force), it is necessary to detect slip sensation information on the stationary or slipping of the object on which the external force is applied with high accuracy. .

  The present invention has been made in view of such circumstances, and detects, in addition to haptic information such as the direction and magnitude of an external force, slip sensation information such as stationary or slipping of an object to which the external force is applied with high accuracy. It is an object of the present invention to provide a detection device that can perform the detection, and an electronic device and a robot on which the detection device is mounted.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

(Application example 1)
The detection device of this application example has a surface on which an external force acts, and a detection device in which an external force detection unit that detects the direction and magnitude of the external force and a slip detection unit that detects a slip displacement generated by the external force are stacked. The external force detection unit includes a first substrate having a plurality of pressure sensors arranged around the reference point, a center of gravity located at a position overlapping with the reference point, and a tip portion contacting the first substrate by an external force. The slip detection unit is electrically connected to the pressure-sensitive conductive sheet and has a resistance value of the pressure-sensitive conductive sheet. And a third substrate on which a pair of electrodes to be detected is formed.

  According to this application example, the elastic protrusion can be deformed in a sliding direction (a direction parallel to the pressure sensor surface) in a state where the tip of the elastic protrusion is in contact with the first substrate (a plurality of pressure sensors). The direction and magnitude of the external force can be detected. Furthermore, since the resistance value of the pressure-sensitive conductive sheet has a changing point in the vicinity of the occurrence of the slip displacement, the occurrence of the slip displacement can be detected from the change in the resistance value of the pressure-sensitive conductive sheet. Accordingly, it is possible to provide a detection device capable of detecting composite information including slip information of stationary or slipping of an object to which an external force is applied in addition to force information of the direction and magnitude of the external force.

(Application example 2)
In the detection device described in the application example, it is preferable that an elastic substrate is provided on a surface on which an external force acts.

  According to this application example, the elastic substrate is installed on the surface on which the external force acts, and the elastic substrate is deformed at the external force application point, so that the external force application point does not move (slide). You can catch it. Therefore, it is possible to obtain an effect that the external force is accurately transmitted to the external force detection unit and the slip detection unit by the elastic substrate.

(Application example 3)
In the detection device described in the application example described above, it is preferable that at least one of a concave portion and a convex portion is formed on a surface on which an external force acts.

  According to this application example, since at least one of the concave portion and the convex portion is formed on the surface on which the external force acts, the frictional force on the surface on which the external force acts increases. Therefore, the action point of the external force does not move (slide), and the external force can be received more accurately. Therefore, an effect that the external force is more accurately transmitted to the external force detection unit and the slip detection unit can be obtained.

(Application example 4)
In the detection device described in the application example, it is preferable that the third substrate, the second substrate, and the first substrate are stacked in order from the side on which the external force acts.

  According to this application example, in order from the side on which the external force acts, a slip detection unit (third substrate) that detects slip displacement and an external force detection unit (second substrate, first) that detects the direction and magnitude of the external force. Since the substrate) is stacked, the external force detection unit can simultaneously detect the haptic information of the direction and magnitude of the external force, and the slip detection unit can simultaneously detect the slip sensation information of the stationary or slipping of the object. Can be obtained.

(Application example 5)
In the detection device according to the application example, the third substrate, the second substrate, and the first substrate are sequentially stacked from the side on which the external force acts, and rigidity is provided between the third substrate and the second substrate. It is preferable that the board | substrate which has is installed.

  According to this application example, since the rigid substrate is installed on the surface opposite to the surface on which the external force acts on the slip detection unit (third substrate), the slip detection unit is deformed even if the external force is applied. Therefore, it is possible to accurately detect the occurrence of a slip displacement caused by an external force acting on the slip detection unit accurately. Furthermore, since a rigid substrate is installed on the surface of the external force detection unit (second substrate, first substrate) on which the external force acts, the external force acts on the entire external force detection unit, not on a single point. . Therefore, the magnitude of external force (distribution of external force) acting on the elastic protrusions at a plurality of locations installed in the external force detector can be obtained. Furthermore, the effect that the rotational moment of the external force which acted from the difference can also be calculated | required can be acquired.

(Application example 6)
In the detection device according to the application example, the third substrate, the second substrate, and the first substrate are sequentially stacked from the side on which the external force acts, and the external force detection unit configured by the second substrate and the first substrate. Is preferably sandwiched between a pair of rigid substrates.

  According to this application example, since the rigid substrate is installed on the surface opposite to the surface on which the external force acts on the slip detection unit (third substrate), the slip detection unit is deformed even if the external force is applied. Therefore, it is possible to accurately detect the occurrence of a slip displacement caused by an external force acting on the slip detection unit accurately. Furthermore, since a rigid substrate is installed on the surface of the external force detection unit (second substrate, first substrate) on which the external force acts, the external force acts on the entire external force detection unit, not on a single point. . Therefore, the rotational moment of the external force can be obtained from the magnitude (distribution of the external force) of the external force acting on the elastic protrusions at a plurality of locations installed in the external force detector and the difference therebetween. Furthermore, since the rigid substrate is installed on the surface opposite to the surface on which the external force acts on the external force detector, the external force detector is deformed even if an external force acts, and the direction of the acting external force is erroneously detected. In addition, it is possible to obtain an effect that the detection unit can be attached to a flexible object that is easily deformed.

(Application example 7)
In the detection device according to the application example, the third substrate, the second substrate, and the first substrate are stacked in order from the side on which the external force acts, and at least one of the second substrate and the third substrate has rigidity. It is preferable that it is a board | substrate which has.

  According to this application example, since at least one of the second substrate and the third substrate has rigidity, the rigidity is between the slip detection unit (third substrate) and the external force detection unit (second substrate, first substrate). Even without newly installing a substrate having the above, it is possible to obtain an effect that the slip detection unit and the external force detection unit can function properly.

(Application example 8)
In the detection apparatus described in the application example, it is preferable that the second substrate, the first substrate, and the third substrate are stacked in order from the side on which the external force acts.

  According to this application example, an external force detection unit (second substrate, first substrate) that detects external force and a slip detection unit (third substrate) that detects slip displacement are stacked in order from the side on which the external force acts. Therefore, it is possible to obtain the effect that the external force detection unit can simultaneously detect the haptic information of the direction and magnitude of the external force, and the slip detection unit can simultaneously detect the sensible information of the stationary or slipping of the object.

(Application example 9)
In the detection device described in the application example, the second substrate, the first substrate, and the third substrate are stacked in order from the side on which the external force acts, and the surface opposite to the surface on which the external force acts is applied to the third substrate. It is preferable that a rigid substrate is installed.

  According to this application example, since the rigid substrate is installed on the surface opposite to the surface on which the external force acts on the slip detection unit (third substrate), the slip detection unit is deformed even if the external force is applied. Therefore, an external force acts accurately on the slip detection unit, and a slip displacement generated by the external force can be accurately detected. Furthermore, it is possible to obtain an effect that the detection device can be attached to a flexible object that is easily deformed.

(Application example 10)
In the detection device described in the application example, the second substrate, the first substrate, and the third substrate are sequentially stacked from the side on which the external force acts, and the third substrate is sandwiched between a pair of rigid substrates. It is preferable.

  According to this application example, since the rigid substrate is installed on the surface opposite to the surface on which the external force acts on the external force detection unit (second substrate, first substrate), the external force detection unit even if the external force is applied. The direction and magnitude of the external force can be more accurately detected without erroneously detecting the direction of the external force acting. Furthermore, since a substrate having rigidity is installed on the surface opposite to the surface on which the external force acts on the slip detection unit (third substrate), the slip detection unit does not deform even if an external force acts on the surface. An external force accurately acts on the slip detection unit, and a slip displacement generated by the external force can be accurately detected. Furthermore, it is possible to obtain an effect that the detection device can be attached to a flexible object that is easily deformed.

(Application Example 11)
In the detection device described in the application example, it is preferable that the second substrate, the first substrate, and the third substrate are stacked in order from the side on which the external force acts, and the third substrate is a rigid substrate.

  According to this application example, since the slip displacement detection unit (third substrate) is a rigid substrate, it does not deform even when an external force is applied, and a predetermined external force acts on the slip displacement detection unit, and the slip The occurrence of displacement can be accurately detected. Furthermore, it is possible to obtain an effect that the detection device can be attached to a flexible object that is easily deformed.

(Application Example 12)
In the detection device described in the application example, it is preferable that the second substrate, the first substrate, and the third substrate are stacked in order from the side on which the external force acts, and the second substrate is a rigid substrate.

  Since the second substrate on which the elastic protrusions are formed is a rigid substrate, an external force acts on the entire first substrate having a plurality of pressure sensors from the second substrate, not on a single point. Therefore, it is possible to obtain an effect that the rotational moment of the external force can be obtained from the magnitude of the external force (distribution of the external force) acting on the elastic protrusions at a plurality of locations installed in the external force detection unit and the difference therebetween.

(Application Example 13)
The detection device described in the application example includes a calculation unit, and the calculation unit is detected by each pressure sensor arbitrarily combined among the pressure values detected by the plurality of pressure sensors when the elastic protrusion is elastically deformed by an external force. It is preferable to perform a calculation process for calculating the difference between the pressure values and calculating the direction of the external force and the magnitude of the external force based on the difference.

  According to this application example, if the external force acting on the detection device includes a force component in the sliding direction (direction parallel to the pressure sensor surface), the center of gravity of the elastic protrusion is displaced from the reference point and moves in the sliding direction. . Then, the ratio of the plurality of pressure sensors that overlap with the portion where the center of gravity of the elastic protrusion moves is relatively large, and different pressure values are detected by each pressure sensor. Specifically, a relatively large pressure value is detected by the pressure sensor at a position overlapping with the center of gravity of the elastic protrusion, and a relatively small pressure value is detected by a pressure sensor at a position not overlapping with the center of gravity of the elastic protrusion. It will be. Therefore, it is possible to obtain an effect that the calculation unit calculates the difference between the pressure values detected by the respective pressure sensors, and can determine the direction and magnitude of the external force applied to the detection device based on the difference. .

(Application Example 14)
The detection device described in the application example includes a calculation unit, and the calculation unit converts a resistance value of the pressure-sensitive conductive sheet into a slip detection signal, and executes calculation processing for detecting occurrence of slip displacement from a change in the slip detection signal. It is preferable.

  Since the resistance value of the pressure-sensitive conductive sheet has a changing point in the vicinity of the occurrence of the sliding displacement, the occurrence of the sliding displacement can be detected from the changing point of the resistance value of the pressure-sensitive conductive sheet. The calculation unit converts the change in the resistance value of the pressure-sensitive conductive sheet into an electric signal (slip detection signal) that can be detected more accurately. Furthermore, the effect that the occurrence of slippage displacement can be detected more accurately is obtained by performing computation processing for detecting the occurrence of slippage displacement from the changing point of the electric signal (slip detection signal) in the computation unit. Can do.

(Application Example 15)
The electronic device described in this application example includes the detection device described in the above application example.

  By mounting the detection device described in the above application example on an electronic device, in addition to the haptic information on the direction and magnitude of the force acting on the electronic device, slip information on stationary or slipping can be used. In addition to the operation of the electronic device based on the information, the electronic device can be operated based on the slip sensation information, and an electronic device capable of various operations can be provided. For example, the detection device on a touch pad of information portable terminal, mobile phone, personal computer, video camera monitor, car navigation device, pager, electronic notebook, calculator, word processor, workstation, video phone, POS terminal, digital still camera, etc. It is possible to provide a wider variety of operability by installing.

(Application Example 16)
The robot described in this application example includes the detection device described in the above application example.

  A robot equipped with the detection device described in the above application example can simultaneously detect slip sensation information such as stationary or slip in addition to haptic information such as the direction and magnitude of the force acting on the object. It is possible to detect the direction and magnitude of the force acting on the object not only in a stationary state but also in a state where the object is sliding, and appropriately control the direction and magnitude of the force acting on the object. Accordingly, it is possible to provide an operation closer to a human, such as an operation of nursing a person (boiling, rubbing, wiping), an operation of processing a flexible material such as clay into a ceramic product.

It is the schematic which shows the structure of the detection apparatus which concerns on 1st Embodiment. It is a schematic diagram which shows the state of the pressure-sensitive conductive sheet which concerns on 1st Embodiment. It is a top view which shows the structure of the electrode sheet which concerns on 1st Embodiment. It is a disassembled perspective view which shows the structure of the external force detection part which concerns on 1st Embodiment. It is an equivalent circuit diagram of the slip detection signal circuit according to the first embodiment. It is an equivalent circuit diagram which shows the structure of the sensing circuit which concerns on 1st Embodiment. It is a timing chart which shows operation of a sensing circuit concerning a 1st embodiment. It is explanatory drawing which shows operation | movement of the sensing circuit in a reset period. It is explanatory drawing which shows operation | movement of the sensing circuit in a sensing period. It is explanatory drawing which shows operation | movement of the sensing circuit in a read-out period. It is sectional drawing which shows the change of the electrostatic capacitance by the capacity | capacitance detection element which concerns on 1st Embodiment. It is a top view which shows the change of the electrostatic capacitance by the capacity | capacitance detection element which concerns on 1st Embodiment. It is a figure which shows the coordinate system of the sensing area | region which concerns on 1st Embodiment. It is a figure which shows the pressure distribution of the perpendicular direction by the capacity | capacitance detection element which concerns on 1st Embodiment. It is a figure which shows the example of calculation of the slip direction by the capacity | capacitance detection element which concerns on 1st Embodiment. It is the schematic of the experimental apparatus which concerns on 1st Embodiment. It is a graph which shows the evaluation result by the experimental apparatus which concerns on 1st Embodiment. It is a disassembled perspective view which shows the structure of the external force detection part which concerns on 2nd Embodiment. It is sectional drawing which shows the change of the pressure value by the pressure sensor of the external force detection part which concerns on 2nd Embodiment. It is a top view which shows the change of the pressure value by the pressure sensor of the external force detection part which concerns on 2nd Embodiment. It is a schematic diagram which shows schematic structure of the portable information terminal which is an example of an electronic device. It is a schematic diagram which shows schematic structure of the robot hand which is an example of a robot.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

(First embodiment)
<Outline of detection device>
FIG. 1 is a schematic diagram illustrating a configuration of a detection device 100 according to the first embodiment.
As illustrated in FIG. 1, the detection device 100 includes a detection unit K to which an external force F indicated by an arrow acts, and a calculation unit E that performs calculation processing on information obtained from the detection unit K.
The detection unit K has a rectangular shape, and an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D are laminated in order from the side on which the external force F acts, and each member is made of an adhesive or an adhesive material. It is glued. The signal obtained from the slip detection unit B is subjected to calculation processing by the calculation unit E, and the occurrence of slip displacement due to the external force F can be obtained. The signal obtained by the external force detection unit D is subjected to calculation processing by the calculation unit E, and the direction and magnitude of the external force F can be obtained.

  Details of components of the detection unit K will be described in order from the side on which the external force F acts. In the following description, the direction along one side of the rectangular detection unit K is the X axis, the direction along two sides orthogonal to the one side and facing each other is the Y axis, and the direction orthogonal to the detection unit K. Is the Z axis. Furthermore, the side on which the external force F acts on the inspection portion K is defined as the upper side (Z-axis (+) direction), and the opposite side is defined as the lower side (Z-axis (−) direction).

<Elastic board A>
The elastic substrate A (see FIG. 1) is a substrate having elasticity that is deformed by the action of the external force F and recovers to its original shape when the external force F is unloaded. As a preferred example, a silicon rubber sheet is used. Yes. The elastic substrate A is deformed at the point of application of the external force F, and the external force F can be received without the action point moving (sliding), so that the external force F is accurately transmitted to the slip detection unit B. As a material for forming the elastic substrate A, in addition to the above-mentioned silicon rubber, natural rubber, acrylic rubber, nitrile rubber, isoprene rubber, urethane rubber, ethylene propylene rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, chloroprene rubber, styrene -Synthetic rubbers such as butadiene rubber, butadiene rubber, and fluorine rubber are suitable. In addition, soft resins such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and fluororesin can be used.

Furthermore, when a concave or convex portion is formed on the surface of the elastic substrate A, the friction coefficient increases, and the external force F can be transmitted to the slip detection unit B more accurately. For example, when a silicon rubber sheet in which a hemisphere having a diameter of 1 mm to 3 mm is formed from silicon rubber by a mold forming method, the external force F is more accurately transmitted to the slip detection unit B. Such a concave portion or convex portion can be formed by a method such as etching by a solvent, coating formation by a dispenser or inkjet, screen printing, or the like, in addition to the mold forming method. The concave portion or the convex portion may be formed of a material different from that of the base substrate.
The elastic substrate A is an example of “an elastic substrate”.

<Slip detection unit B>
FIG. 2 is a schematic diagram showing the state of the slip detection unit B before and after the external force F acts. The slip detection unit B has flexibility, and a predetermined external force F acts on the slip detection unit B by being sandwiched between the elastic substrate A and the rigid substrate C. Therefore, FIG. The substrate C is also illustrated.

FIG. 2A shows a state where no external force is acting. FIG. 2B shows a state in which an external force F in the compression direction (Z-axis (−) direction) is applied. FIG. 2C shows a state before the occurrence of sliding displacement in which a force in the sliding direction (a direction horizontal to the surface of the elastic substrate A) is applied in addition to the force in the compression direction, that is, an external force F in an oblique direction is applied. The state before the occurrence of the sliding displacement is shown. FIG. 2 (d) shows a state after sliding displacement in which an external force in an oblique direction is applied. Furthermore, the dotted line in FIG.2 (b)-FIG.2 (d) has shown the outline of the pressure-sensitive conductive sheet in the state where the external force F is not acting.
FIG. 3 is a plan view of the electrode sheet B2. The details of the slip detection unit B will be described below with reference to FIGS.

  As shown in FIG. 1, the slip detection unit B has a two-layer structure in which a pressure-sensitive conductive sheet B1 is stacked on the upper side (side on which the external force F acts) and an electrode sheet B2 is stacked on the lower side. The electrode sheet B2 is an example of “a third substrate on which a pair of electrodes are formed”.

As shown in FIG. 2, the pressure-sensitive conductive sheet B1 is a conductor that is formed by dispersing conductive particles B1b such as carbon particles in a nonconductive elastomer resin B1a such as silicon rubber, and is deformed by an external force F. . In FIG. 2, the conductive particles B1b that are in contact with each other to form a conductive path are indicated by black circles, and the conductive particles B1b that are not formed with a conductive path are indicated by white circles.
Due to the external force F, the resistance value of the pressure-sensitive conductive sheet exhibits the following changes.

(1) When the external force F is not applied, the number of the conductive particles B1b that are in contact with each other is small, and almost no conductive path is formed, so that a very large resistance value of 10 ⁷ Ω or more is exhibited (see FIG. 2 (a)).
(2) When an external force F in the compression direction is applied, the conductive particles B1b approach each other and the number of the conductive particles B1b in contact with each other increases, so that a conductive path is formed, and the state shown in FIG. The resistance value becomes smaller (FIG. 2B). The same applies to FIG. 2 (c) and FIG. 2 (d).
(3) When an external force in the sliding direction, that is, an external force F in the oblique direction, acts in addition to the external force in the compression direction, the pressure-sensitive conductive sheet B1 extends in the sliding direction, so that the conductive particles B1 b that are separated from each other increase. The conductive particles B1b forming the path are reduced, and the resistance value becomes larger than that in the state of FIG. In addition, immediately before the occurrence of the sliding displacement, the pressure-sensitive conductive sheet B1 is in the most extended state in the sliding direction. For this reason, the resistance value becomes the largest in the vicinity where the sliding displacement occurs (FIG. 2C).
(4) Although details will be described later, when the sliding displacement occurs, the external force F in the sliding direction becomes small, so that the elongation of the pressure-sensitive conductive sheet in the sliding direction becomes small. For this reason, the separated conductive particles B1b approach, the conductive particles B1b forming the conductive path increase, and the resistance value becomes smaller than the state of FIG. 2C before the sliding displacement occurs. (FIG. 2 (d)).

  Thus, the pressure-sensitive conductive sheet B1 is deformed by the external force F, and the conductive particles B1b are brought into contact with or separated from each other, and the resistance value of the pressure-sensitive conductive sheet B1 changes.

As shown in FIG. 3, the electrode sheet B2 is a resin film on which two comb-shaped electrodes 110 and 111 and two electrode terminals 110a and 111a are formed. The electrode sheet B2 is fixed so as to be electrically connected to the pressure-sensitive conductive sheet B1, and the resistance value of the pressure-sensitive conductive sheet B1 is monitored from the electrode terminal 110a and the electrode terminal 111a.
The purpose of the electrode sheet is to monitor the resistance value of the pressure-sensitive conductive sheet. For example, two electrodes may be formed in a spiral shape. For example, two electrodes are arranged on different substrates, and the pressure is sensed by two substrates. It is good also as a structure which clamps a conductive sheet.

<Rigid substrate C>
The rigid substrate C (see FIG. 1) is an aluminum plate having a thickness of 0.5 mm. As a material for forming the rigid substrate C, light metals such as aluminum, magnesium and titanium, alloys based on these light metals, glass, quartz, ceramics, acrylic resins, polycarbonate resins, phenol resins, melamine resins, urea resins, Hard resins such as FRP (fiber reinforced plastic) and PET (polyethylene terephthalate) are suitable. A metal such as SUS, iron, or nickel can be used as the rigid substrate C, but a light metal having a small specific gravity, such as aluminum, is preferable for weight reduction.

The rigid substrate C has the following role.
(1) By disposing the rigid substrate C under the slip detector B, the slip detector B does not deform even if it has flexibility, and a predetermined external force F acts on the slip detector B. To do.
(2) By disposing the rigid substrate C on the external force detection unit D, the external force F acts on the entire external force detection unit D, not locally. Therefore, the rotational force of the external force can be detected from the magnitude of the external force (distribution of the external force) and the difference between them at a plurality of locations of the external force detector D.
The rigid substrate C is an example of a “stiff substrate”.

<External force detection part D>
The external force detector D (see FIG. 4) includes a substrate having an elastic protrusion 32 that applies an external force F to a reference point, and a capacitance type pressure sensor that detects a pressure value of the external force F applied to the reference point. Is done. The “reference point” is a point at which the center of the elastic protrusion 32 is located when no sliding force is applied.

FIG. 4 is an exploded perspective view showing a schematic configuration of the external force detector D. In FIG. 4, the dielectric 40 (see FIG. 11) is not shown for convenience. In FIG. 4, reference symbol P denotes a reference point, and reference symbol S denotes a plurality of capacitance detection elements S <b> 1 to S <b> 4 (first capacitance electrode 12, second capacitance electrode 22, and dielectric 40) arranged corresponding to one elastic protrusion 32. A unit detection region detected by a capacitance detection element configured by
The capacitance detection element including the first capacitance electrode 12, the second capacitance electrode 22, and the dielectric 40 is an example of a “pressure sensor”.

As shown in FIG. 4, the external force detection unit D includes a first capacitance electrode substrate 10 having a plurality of first capacitance electrodes 12 arranged around the reference point P, and a first capacitance electrode across the first capacitance electrode 12. The second capacitor electrode substrate 20 disposed opposite to the substrate 10, the dielectric 40 (see FIG. 11) disposed between the first capacitor electrode substrate 10 and the second capacitor electrode substrate 20, and the reference point P overlap. And a second substrate 30 on which an elastic protrusion 32 is formed, which is elastically deformed in a state where the center of gravity is located at the position and the tip is in contact with the second capacitor electrode substrate 20 by an external force.
The element substrate composed of the first capacitor electrode substrate 10, the second capacitor electrode substrate 20, and the dielectric 40 is an example of “a first substrate having a pressure sensor”. The second substrate 30 on which the elastic protrusions 32 are formed is an example of “a second substrate on which elastic protrusions are formed”.

  The first capacitor electrode substrate 10 includes, for example, a rectangular first capacitor electrode substrate body 11 made of a material such as glass, quartz, and plastic, and a plurality of first capacitor electrodes disposed on the first capacitor electrode substrate body 11. 12. For example, the size (plan view size) of the first capacitor electrode substrate body 11 is about 56 mm long × 56 mm wide.

  The plurality of first capacitor electrodes 12 are arranged point-symmetrically with respect to the reference point P. For example, the plurality of first capacitor electrodes 12 are arranged in a matrix in two directions (X direction and Y direction) orthogonal to each other. As a result, the distance between the reference point P and each first capacitance electrode 12 becomes equal to each other, so that each capacitance detection element S1 to S4 including each first capacitance electrode 12 and second capacitance electrode 22 is provided. The capacitance values detected by are equal to each other. Therefore, it becomes easy to calculate the difference between the capacitance values of the capacitance detection elements S1 to S4 arbitrarily combined among the capacitance values of the capacitance detection elements S1 to S4. A method for calculating the difference between the capacitance values will be described later.

  The interval between the adjacent first capacitor electrodes 12 is about 0.1 mm. For this reason, noise is prevented from appearing in the capacitance values detected by the capacitance detection elements S1 to S4 at adjacent positions due to the influence of disturbance, static electricity, and the like.

The plurality of first capacitance electrodes 12 are arranged in a total of four per unit detection region S in two rows and two columns. The center of the four first capacitor electrodes 12 (the center of the unit detection region S) is the reference point P. For example, the size of the unit detection area S (size in plan view) is about 2.8 mm long × 2.8 mm wide. Further, the areas of the four first capacitor electrodes 12 are substantially equal. As a material for forming the first capacitor electrode 12, for example, a metal material such as aluminum (Al) can be used.
In the present embodiment, a total of four first capacitance electrodes 12 are arranged in two vertical rows and two horizontal columns per unit detection region S, but the present invention is not limited to this. Three or more first capacitance electrodes 12 may be arranged per unit detection region S. For example, a total of nine first capacitance electrodes 12 may be arranged in three rows and three columns. It may be arranged individually.

  The second capacitor electrode substrate 20 includes a rectangular second capacitor electrode substrate body 21 made of a material such as plastic, and a second capacitor electrode 22 disposed on the second capacitor electrode substrate body 21. Configured. The second capacitor electrode substrate body 21 is formed to a thickness that is flexible when an external force is applied to the contact surface. The second capacitor electrode substrate body 21 is formed in the same size as the first capacitor electrode substrate body 11 in plan view.

  The second capacitor electrode 22 is disposed at a position overlapping the entirety of the plurality of first capacitor electrodes 12. Specifically, the second capacitor electrode 22 is formed over the entire exposed portion of the lower surface of the second capacitor electrode substrate body 21. As a material for forming the second capacitor electrode 22, for example, a metal material such as aluminum (Al) can be used in the same manner as the first capacitor electrode 12.

  The dielectric 40 (see FIG. 11) is made of an elastic body or a fluid disposed between the first capacitor electrode substrate 10 and the second capacitor electrode substrate 20. As a material for forming the dielectric 40, for example, an elastic body such as rubber can be used, or a fluid such as silicon oil or liquid crystal can be used.

  Between the first capacitor electrode substrate 10 and the second capacitor electrode substrate 20, a plurality of spacers (not shown) that keep the distance between the first capacitor electrode substrate 10 and the second capacitor electrode substrate 20 constant are arranged. ing. The plurality of spacers are arranged on the outer periphery of the region where the elastic protrusions 32 are arranged in a matrix. Accordingly, the dielectric 40 is configured to have a certain thickness in the Z direction between the first capacitor electrode substrate 10 and the second capacitor electrode substrate 20.

  The second substrate 30 includes a rectangular second substrate body 31 and a plurality of elastic protrusions 32 disposed on the second substrate body 31. An external force F acts on the second substrate body 31 via the rigid substrate C. The second substrate body 31 can be made of a material such as glass, quartz, and plastic, or can be made of a resin material such as foamed urethane resin. In the present embodiment, a resin material is used as a material for forming the second substrate body 31 and the elastic protrusions 32, and the second substrate body 31 and the elastic protrusions 32 are integrally formed with a mold.

  The plurality of elastic protrusions 32 are arranged in a matrix in the X direction and the Y direction on the second substrate body 31. The tip of the elastic protrusion 32 has a spherical weight shape and is in contact with the second capacitor electrode substrate body 21. The center of gravity of the elastic protrusion 32 is arranged at a position overlapping the reference point P. Further, the plurality of elastic body protrusions 32 are spaced apart from each other. For this reason, it is possible to allow a deformation amount in a direction parallel to the surface of the second substrate body 31 when the elastic protrusion 32 is elastically deformed.

  The size of the elastic protrusion 32 can be arbitrarily set. Here, the diameter of the base of the elastic protrusion 32 (the diameter of the portion where the elastic protrusion 32 contacts the second substrate body 31) is about 1.8 mm. The height of the elastic protrusion 32 (the distance in the Z direction of the elastic protrusion 32) is about 2 mm. The spacing between adjacent elastic protrusions 32 is about 2 mm. The durometer hardness of the elastic projection 32 (type A, measured by a durometer conforming to ISO7619) is about 30.

<Calculation unit E related to slip detection>
Next, details of the role of the calculation unit E related to slip detection will be described with reference to FIG.
FIG. 5 is an equivalent circuit diagram of the slip detection signal generation circuit 120.
FIG. 5 also shows a slip detection unit B in order to explain the operation of the slip detection signal generation circuit 120 in an easily understandable manner. In FIG. 5, the pressure-sensitive conductive sheet of the slip detection unit B is illustrated as a variable resistor 121.
As shown in FIG. 5, the slip detection signal generation circuit 120 includes a reference resistor 122, a DC power source 123, and output terminals 110b and 111b. The slip detection signal B surrounded by the dotted line is connected in series with the reference resistor 122 of the slip detection signal generation circuit 120 via the electrode terminals 110a and 111a of the slip detection unit B. By this equivalent circuit, a divided voltage is output from both ends of the variable resistor 121 (the pressure-sensitive conductive sheet of the slip detection unit B) and becomes a slip detection signal Vs.
Thus, the slip detection signal generation circuit 120 converts the resistance value of the pressure-sensitive conductive rubber B1 of the slip detection unit B into the slip detection signal Vs, and the occurrence of slip displacement is detected from the slip detection signal Vs.
Details of the method for detecting the occurrence of slip displacement will be described later.

<Calculation unit E related to external force detection>
Regarding the external force detection unit D (see FIG. 4), the difference between the capacitance values of the capacitance detection elements arbitrarily combined among the capacitance values of the plurality of capacitance detection elements S1 to S4 that change due to the external force is calculated. Based on the difference, the direction in which the external force is applied and the magnitude of the external force can be obtained.

<Sensing circuit>
FIG. 6 is an equivalent circuit diagram of a sensing circuit 60 that detects an external force using a capacitance detection element. In FIG. 6, the capacitance detection element including the first capacitance electrode 12, the second capacitance electrode 22, and the dielectric 40 in the external force detection unit D is illustrated as a variable capacitance with a symbol Cl.
The sensing circuit 60 includes a reset transistor 61, an amplification transistor 62, a selection transistor 63, and a reference capacitance element Cr, and is connected to the capacitance detection element Cl of the external force detection unit D. A common potential Vcom is supplied to the second capacitance electrode 22 of the capacitance detection element Cl.

  The drain of the reset transistor 61 is connected to the power supply line 70. The source of the reset transistor 61 is connected to the gate of the amplification transistor 62. A power supply potential VRH is supplied to the power supply line 70. The gate of the reset transistor 61 is connected to the first control line 72. A reset signal RES is supplied to the first control line 72.

  The drain of the amplification transistor 62 is connected to the power supply line 70. The source of the amplification transistor 62 is connected to the drain of the selection transistor 63. A reference capacitive element Cr is provided between the gate of the amplification transistor 62 and the first control line 72. The gate of the amplification transistor 62 is connected to the first capacitance electrode 12 of the capacitance detection element Cl.

  The source of the selection transistor 63 is connected to the detection line 74. The gate of the selection transistor 63 is connected to the second control line 76. A selection signal SEL is supplied to the second control line 76.

<Circuit operation>
Next, the operation of the sensing circuit 60 will be described with reference to FIGS.
FIG. 7 is a timing chart showing the operation of the sensing circuit 60 according to the present embodiment. FIG. 8 is an explanatory diagram showing the operation of the sensing circuit 60 during the reset period. FIG. 9 is an explanatory diagram illustrating the operation of the sensing circuit 60 during the sensing period. FIG. 10 is an explanatory diagram showing the operation of the sensing circuit 60 during the readout period.
As shown in FIG. 7, the sensing circuit 60 operates with the reset period Tres, the sensing period Tsen, and the readout period Tout as one unit.

<Reset period>
First, in the reset period Tres, the level of the reset signal RES supplied to the first control line 72 is set to the potential VD. That is, in the reset period Tres, the level of the reset signal RES is set to a high level, and the reset transistor 61 is turned on. On the other hand, the selection signal SEL supplied to the second control line 76 is set to a low level, and the selection transistor 63 is turned off. Then, as shown in FIG. 8, the gate potential VA of the amplification transistor 62 is set (reset) to the power supply potential VRH. The power supply potential VRH is also supplied to the first capacitance electrode 12 of the capacitance detection element Cl, and the voltage between the first capacitance electrode 12 and the second capacitance electrode 22 of the capacitance detection element Cl is set to VRH−Vcom. .

<Sensing period>
Next, in the sensing period Tsen, which is the next period after the lapse of the reset period Tres, the level of the reset signal RES changes from VD to GND (= 0V). Then, as shown in FIG. 9, the reset transistor 61 is turned off. In the sensing period Tsen, the selection signal SEL is set to a low level, and the selection transistor 63 is turned off. Since the impedance of the gate of the amplification transistor 62 is sufficiently high, the gate of the amplification transistor 62 is in an electrically floating state during the sensing period Tsen. A reset signal RES is supplied to one electrode of the reference capacitive element Cr via the first control line 72, and the signal level changes from VD to GND. Then, the potential VA of the gate of the amplification transistor 62 changes accordingly. The amount of change in the gate potential VA at this time is a value corresponding to the capacitance ratio between the reference capacitance element Cr and the capacitance detection element Cl.

<Reading period>
In the readout period Tout that is the period following the sensing period Tsen, the selection signal SEL changes from the low level to the high level. Then, as shown in FIG. 10, the selection transistor 63 is turned on. As a result, a detection current It having a magnitude corresponding to the gate potential VA of the amplification transistor 62 flows through the detection line 74. The detection current It is supplied to a detection circuit (not shown) that detects contact between an object (for example, a finger) and the external force detection unit D.

  When the capacitance value of the capacitance detection element Cl changes during the sensing period Tsen, the potential VA of the gate of the amplification transistor 62 also changes accordingly. Therefore, the value of the detection current It that is output in the reading period Tsen when the object is not in contact with the detection apparatus 100, and the detection current that is output in the reading period Tsen when the object is in contact with the external force detection unit D. It is different from the value of It.

  Here, the capacitance value of the capacitance detection element Cl when the object is not in contact with the external force detection unit D is Clc, and the change amount of the capacitance value of the capacitance detection element Cl when the object is in contact with the external force detection unit D is ΔClc, When the capacitance value of the reference capacitive element Cr is Cref and the potential change of the first control line 72 is ΔV (= VD), the change amount ΔVA of the gate potential VA of the amplification transistor 62 when the object contacts the external force inspection unit D Is represented by the following formula (1). However, the parasitic capacitance is ignored in the equation (1).

  The detection circuit (not shown) detects contact between the object and the detection device 100 based on the value of the detection current It (corresponding to a detection signal). The greater the amount of change ΔVA in the gate potential VA when the object is in contact with the external force detection unit D, the greater the difference between the value of the detection current It at the time of non-contact and the value of the detection current It at the time of contact. Also gets higher.

  11 and 12 are explanatory diagrams of a method for detecting the direction and magnitude of the external force acting on the reference point P. FIG.

  FIGS. 11A to 11C are cross-sectional views illustrating changes in capacitance by the capacitance detection element according to the first embodiment. FIGS. 12A to 12C are plan views showing changes in capacitance in the capacitance detection element according to the first embodiment, corresponding to FIGS. 11A to 11C. 11A and 12A show a state before an external force is applied to the surface of the second substrate 30 (when no external force is applied). FIG. 11B and FIG. 12B show a state in which an external force in a vertical direction (a state without a sliding force) is applied to the surface of the second substrate 30. FIG. 11C and FIG. 12C show a state in which an external force in an oblique direction (with a sliding force) is applied to the surface of the second substrate 30. In FIGS. 12A to 12C, the symbol G indicates the center of gravity (pressure center) of the elastic protrusion 32.

  As shown in FIGS. 11A and 12A, the elastic protrusion 32 is not deformed before an external force is applied to the surface of the second substrate 30. Thereby, the distance between the first capacitor electrode 12 and the second capacitor electrode 2 is kept constant. At this time, the center of gravity G of the elastic protrusion 32 is disposed at a position overlapping the reference point P. The capacitance values of the capacitance detection elements S1 to S4 at this time are stored in a memory (not shown). The direction and size in which an external force acts is determined based on the capacitance values of the capacitance detection elements S1 to S4 stored in the memory.

  As shown in FIGS. 11B and 12B, when an external force in the vertical direction is applied to the surface of the second substrate 30, the elastic protrusion 32 has a tip portion on the surface of the second capacitor electrode substrate 20. Compressed and deformed in the Z direction while in contact. As a result, the second capacitor electrode substrate 20 bends in the −Z direction, and the distance between the first capacitor electrode 12 and the second capacitor electrode 22 becomes smaller than when there is no external force. That is, the capacitance value of the capacitance detection element at this time becomes larger than when there is no external force.

  The elastic protrusion 32 is compressed and deformed according to the magnitude of the external force. When the external force increases, the elastic protrusion 32 reaches a critical point where it does not deform any more. When an external force exceeding the critical point acts on the elastic protrusion 32, the dielectric 40 is deformed flexibly in the Z direction. For this reason, it is possible to detect an external force having a magnitude greater than or equal to a critical point at which the elastic protrusion 32 can be deformed.

  As shown in FIGS. 11C and 12C, when an external force in an oblique direction is applied to the surface of the second substrate 30, the elastic protrusion 32 has a tip portion on the surface of the second capacitor electrode substrate 20. In the abutting state, it is inclined and inclined and compressed. As a result, the second capacitor electrode substrate 20 bends in the −Z direction, and the distance between the first capacitor electrode 12 and the second capacitor electrode 22 becomes smaller than when there is no external force. Further, the amount of deflection of the second capacitor electrode substrate 20 is greater in the + X direction component than in the −X direction component. At this time, the center of gravity G of the elastic protrusion 32 is shifted from the reference point P in the + X direction and the + Y direction. In this case, the overlapping areas of the tip of the elastic protrusion 32 and the four first capacitor electrodes 12 are different from each other. Specifically, the overlapping area of the tip of the elastic protrusion 32 and the four first capacitor electrodes 12 overlaps with the portion of the four first capacitor electrodes 12 arranged in the −X direction and the −Y direction. The area overlapping with the portions arranged in the + X direction and the + Y direction is larger than that.

  The elastic protrusion 32 is compressed and deformed obliquely according to the magnitude of the external force, and reaches a critical point where it does not deform any more as the external force increases. Further, the elastic protrusion 32 is biased in deformation due to an oblique external force. That is, the center of gravity of the elastic protrusion 32 is displaced from the reference point P and moves in the sliding direction (X direction and Y direction). Then, the thickness of the dielectric 40 in the portion where the center of gravity of the elastic protrusion 32 has moved becomes relatively thin. That is, different capacitances are detected by each capacitance detection element. Specifically, a relatively large capacitance is detected in the capacitance detection element at a position overlapping the gravity center of the elastic protrusion 32, and a relatively small static is detected in the capacitance detection element at a position not overlapping with the gravity center of the elastic protrusion 32. The electric capacity will be detected. And the direction and magnitude | size where the external force acted are calculated | required based on the calculation method of the difference mentioned later.

  FIG. 13 is a diagram illustrating a coordinate system of the sensing area according to the first embodiment. FIG. 14 is a diagram illustrating an external force distribution in the vertical direction by the capacitance detection element according to the first embodiment. FIG. 15 is a diagram illustrating a calculation example of the slip direction by the capacitance detection element according to the first embodiment.

As shown in FIG. 13, a plurality of capacitance detection elements S1, S2, S3, and S4 are arranged in a unit of two rows and two columns per unit detection region S. Here, assuming that capacitance values (detection values) detected by the capacitance detection elements S1, S2, S3, and S4 are P _S1 , P _S2 , P _S3 , and P _S4 , respectively, the X direction component Fx of the external force (the external force) The ratio of the component force acting in the X direction out of the in-plane direction component is expressed by the following formula (2).

  Further, the Y direction component Fy of the external force (the ratio of the component force acting in the Y direction among the in-plane direction components of the external force) is expressed by the following equation (3).

  Further, the Z direction component Fz of the external force (vertical direction component of the external force) is expressed by the following formula (4).

  In the present embodiment, the electrostatic capacitance of each capacitance detection element arbitrarily combined among the capacitance values of the four capacitance detection elements S1, S2, S3, and S4 that change when the elastic protrusion 32 is elastically deformed by an external force. The difference between the capacitance values is calculated, and the direction and magnitude in which the external force is applied is calculated based on the difference.

  As shown in Expression (2), in the X-direction component Fx of the external force, the capacitance detection elements S2 and S4 arranged in the + X direction among the capacitance values of the four capacitance detection elements S1, S2, S3, and S4 are In addition, the capacitance detection elements S1 and S3 arranged in the −X direction are combined. As described above, based on the difference between the capacitance value by the combination of the capacitance detection elements S2 and S4 arranged in the + X direction and the capacitance value by the combination of the capacitance detection elements S1 and S3 arranged in the -X direction. The X direction component of the external force is obtained.

  As shown in Expression (3), in the Y-direction component Fy of the external force, the capacitance detection elements S1 and S2 arranged in the + Y direction among the capacitance values of the four capacitance detection elements S1, S2, S3, and S4 are In addition to the combination, the capacitance detection elements S3 and S4 arranged in the −Y direction are combined. As described above, based on the difference between the capacitance value by the combination of the capacitance detection elements S1 and S2 arranged in the + Y direction and the capacitance value by the combination of the capacitance detection elements S3 and S4 arranged in the -Y direction. The Y direction component of the external force is obtained.

  As shown in Expression (4), the Z-direction component Fz of the external force is obtained by a resultant force obtained by adding the capacitance values of the four capacitance detection elements S1, S2, S3, and S4. However, the Z direction component Fz of the external force tends to be detected with a larger detection value than the X direction component Fx of the external force and the Y direction component Fy (component force) of the external force. For example, if a hard material is used as the material of the elastic protrusion 32 or the shape of the tip is sharpened, the external force detection sensitivity is increased. However, if a hard material is used as the material of the elastic protrusion 32, the elastic protrusion 32 is not easily deformed, and the detected value of the external force in the in-plane direction becomes small. Further, when the shape of the tip of the elastic protrusion 32 is sharpened, a strong sensitivity (uncomfortable feeling) may be given to the touch feeling when the contact surface is touched with a finger. Therefore, in order to align the detected value of the Z direction component Fz of the external force with the detected value of the X direction component Fx of the external force and the detected Y direction component Fy of the external force, a correction coefficient determined by the material and shape of the elastic protrusion 32 is used. It is necessary to correct the detection value as appropriate.

As shown in FIG. 14, a case is considered in which the upper left position of the detection surface of the external force detection unit D (the surface on which the external force acts on the elastic substrate A) is obliquely pushed with a finger. In the external force detection unit D, unit detection areas S are arranged in a matrix of 15 rows × 15 columns (225 in total). That is, the rectangular grid surrounded by the solid line in FIG. 14 is the unit detection region S, and each unit detection region S has four capacitance detection elements S1 to S4 (not shown) in two rows and two columns. .
At this time, the pressure in the vertical direction of the external force is greatest at the central portion of the portion where the external force is applied (about 90 to 120 mV). Moreover, the pressure in the vertical direction of the external force decreases in the order of the peripheral portion (about 60 to 90 mV) and the outermost peripheral portion (about 30 to 60 mV) next to the central portion. Moreover, the area | region which is not pressed with the finger | toe is about 0-30 mV.

  As shown in FIG. 15, a method for calculating an in-plane direction component (slip direction) of external pressure when a position closer to the upper left than the center of the detection surface of the external force detection unit D is obliquely pressed with a finger will be considered. The finger pressing force (external force) acts on the unit detection areas S of the unit detection areas S arranged in 15 rows × 15 columns arranged in 3 rows × 3 columns. To do.

FIG. 15A shows a total value (P _S1 + P _S2 + P _S3 + P _S4 ) of the detection values of the four capacitance detection elements S1 to S4 in the unit detection region S to which an external force is applied. FIG. 15B shows the detection values (P _S1 , P _S2 , P _S3 , P _S4 ) of the four capacitance detection elements S1 to _S4 in the unit detection region for each unit detection region S. In FIG. 15B, the solid line indicates the boundary of the unit detection region S, and the dotted line indicates the boundary of the capacitance detection elements S1 to S4. FIG. 15C shows the layout and coordinate system of the four capacitance detection elements S1 to S4 arranged in the unit detection region S surrounded by the dotted line Q in FIG. Further, as shown in FIG. 15C, the detection values of the capacitance detection elements S1 to S4 are P _{S1 to} P _S4 . The four capacitance detection elements S1 to S4 in the other unit detection regions S in FIG. 15B also have the same layout and coordinate system. FIG. 15D shows, for each unit detection region S, the X-direction component Fx of the external force and the Y-direction component Fy of the external force obtained by the above-described equations (1) and (2).

The direction in which the external force acts is determined by, for example, a method of obtaining an average value of nine calculation results shown in FIG. 15D, for example, a maximum value (for example, a detection value larger than a predetermined threshold value) among the nine calculation results. It can be obtained using a method for obtaining it. Here, the nine calculation results shown in FIG. 15D are averaged to obtain the X direction component Fx of the external force and the Y direction component Fy of the external force. The external force is about 123 ° counterclockwise with respect to the + X direction. It can be seen that it is acting in the direction of.
In this way, each unit detection region S arranged in 3 vertical rows by 3 horizontal columns has four capacitance detection elements S1 to S4, respectively, and the electrostatic capacitance detected by each capacitance detection element S1 to S4. A difference between the capacitance values of the capacitance detection elements S1 to S4 arbitrarily combined among the capacitance values is calculated, and a direction in which an external force is applied is calculated based on the difference.

<Experiment using detection device>
FIG. 16 is a schematic diagram of an experimental apparatus 200 using the detection apparatus 100. In FIG. 16, the calculation unit E that configures the detection device 100 is not shown.
The experimental apparatus 200 includes a pressing member 201, a detection unit K, a gripping member 202, and a carriage 203. The pressing member 201 is an acrylic plate. In the detection unit K, an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D are stacked in order from the pressing member 201 side. The holding member 202 is an acrylic plate. The detection part K is bonded to the pressing member 201, the gripping member 202 is bonded to the carriage 203, and the carriage 203 is bonded to the carriage 203 with an adhesive.
In the experimental apparatus 200, a 6N vertical direction (Z-axis (−) direction) external force (hereinafter referred to as a vertical load) acts on the detection unit K (elastic substrate A) from the pressing member 201, and a sliding direction ( An external force Fs in the X-axis (−) direction is acting. By applying such an external force, it can be considered that the external force in the oblique direction in which the vertical load 6N and the external force Fs in the sliding direction are combined is applied from the pressing member 201 to the detection unit K.

  The magnitude of the external force Fs in the sliding direction is measured by the external force detector D. The slip detection signal Vs is measured by the slip detection unit B. The vertical load acting surface (the position of the elastic substrate A) in the detection unit K is measured by a laser displacement meter (not shown), and the amount of displacement (movement distance with respect to the initial stage) is calculated. Using such an experimental apparatus 200, the external force Fs in the sliding direction was changed, and the slip detection signal Vs before and after the occurrence of the sliding displacement, the external force Fs in the sliding direction, and the displacement amount were measured.

FIG. 17 shows the experimental results. 17A shows the change with time of the slip detection signal Vs measured by the slip detection unit B, FIG. 17B shows the change with time of the external force Fs in the slip direction measured by the external force detection unit D, and FIG. (C) has shown the time-dependent change of the displacement amount of the detection part K (elastic board | substrate A). The horizontal axis of each graph is the elapsed time, and the scale is the same in FIGS. 17 (a) to 17 (c). An external force Fs in the sliding direction was applied to the detection unit K from ta (approximately 0.23 seconds) on the horizontal axis, and slip displacement occurred at tb (approximately 0.34 seconds) on the horizontal axis.
T1 is a period in which the external force Fs in the sliding direction is not applied, T2 is a period until the external force Fs is applied and slip displacement is generated (ta to tb), and T3 is a period after the slip displacement is generated (after tb). And Below, the state of the experimental apparatus 200 regarding the period T1, the period T2, and the period T3 will be described.

(1) Period T1
Since a 6N vertical load is applied to the detection unit K, the slip detection unit B is compressed and deformed, and a substantially constant slip detection signal Vs of approximately 0.5V is generated. Further, since the external force Fs in the sliding direction is zero, the amount of displacement is also zero.

(2) Period T2
When an external force Fs in the sliding direction acts on the detection unit K, a force against the external force Fs, that is, a static friction force acts in a direction opposite to the external force Fs, and the detection unit K maintains a stationary state. Here, there is a relationship of static friction force = vertical load (6N) × static friction coefficient, and the static friction force changes in proportion to the external force Fs. The external force Fs in the period T2 corresponds to this static friction force. Further, the external force Fs increases with time. When the external force Fs becomes larger than the maximum static frictional force, a slip displacement occurs in the detection unit K. The external force Fs immediately before the occurrence of the sliding displacement, that is, the external force Fs at time tb (approximately 0.34 seconds) in FIG. 17B corresponds to the maximum static friction force (vertical load (6N) × maximum static friction coefficient). .

  When the external force Fs in the sliding direction is applied, the slip detection unit B and the elastic substrate A extend in the sliding direction, and the conductive particles B1b that are separated from each other increase in the slip detection unit B, so that the resistance value gradually increases. For this reason, as shown to Fig.17 (a), the slip detection signal Vs converted from the said resistance value becomes large gradually. Further, as shown in FIG. 17C, an increase in the amount of displacement is observed although it is slight. This indicates the elongation in the sliding direction of the detection unit K at the stage before the occurrence of the sliding displacement.

(3) Period T3
Slip displacement starts at time t2, and the detection unit K moves in the direction in which the external force Fs acts, that is, slip displacement occurs. Here, since the dynamic friction force acts on the detection unit K, the external force Fs in the period T3 corresponds to the dynamic friction force. In addition, the relationship of dynamic friction force = vertical load (6N) × dynamic friction coefficient is established, and the dynamic friction coefficient is smaller than the maximum static friction coefficient. Therefore, when slip displacement occurs, the external force Fs rapidly decreases. After the occurrence of the sliding displacement, a stick-and-slip phenomenon (sliding vibration), that is, a phenomenon in which the detecting unit K repeats the operation of sliding or catching on the pressing member 201, the external force Fs varies within a certain range. It becomes.

  The time point when the external force Fs becomes maximum in FIG. 17B is the time point when the slip displacement occurs. The P3 region in FIG. 17B shows the stick-and-slip phenomenon described above. Further, as shown in FIG. 17A, the slip detection signal Vs becomes maximum immediately after the slip displacement occurs.

<Slip displacement detection method>
As described above, since the slip displacement occurs when the external force Fs becomes the maximum, it should be possible to detect the occurrence of the slip displacement from the change of the external force Fs. However, in the case of an object having a small difference between the maximum static friction coefficient and the dynamic friction coefficient. It is difficult to detect the slip displacement from the change in the external force Fs. That is, in an acrylic plate having a large difference between the maximum static friction coefficient and the dynamic friction coefficient, the external force Fs shows the change shown in FIG. 17B, and it is possible to detect slip displacement, but the cloth and surface are softly deformed. In a material that is easy to do, the difference between the maximum static friction coefficient and the dynamic friction coefficient is small, and the change in the external force Fs is very small. Therefore, it is difficult to detect the occurrence of the slip displacement from the change in the external force Fs.

  On the other hand, the slip detection signal Vs is a divided voltage converted from the resistance value of the pressure-sensitive conductive rubber B1 constituting the slip detection unit B by the slip detection signal generation circuit 120 (see FIG. 5), and slip displacement is generated. There is a characteristic that it increases in the vicinity. Specifically, as schematically shown in FIGS. 2C and 2D, a shape change occurs in the sliding direction before and after the sliding displacement occurs, and the resistance value of the pressure-sensitive conductive rubber B1, that is, A change point of the slip detection signal Vs occurs. Furthermore, since the slip detection signal Vs does not depend on the above-described friction coefficient (maximum static friction coefficient, dynamic friction coefficient), the occurrence of slip displacement can be detected even if the cloth or the surface is a soft and easily deformable material. . As described above, even if the material is difficult to detect the occurrence of the slip displacement by the external force detection unit D, the slip detection unit B can detect the occurrence of the slip displacement.

  In this experiment, the slip detection signal Vs was maximized immediately after the slip displacement occurred. In an experiment using the pressing member 201 made of another material, the point in time when the slip detection signal Vs was maximum had a certain range of distribution. That is, the time point at which the slip detection signal Vs becomes maximum varies depending on the type of the pressing member 201, the surface shape, etc., and becomes the maximum immediately before the occurrence of the slip displacement, when it becomes the maximum simultaneously with the occurrence of the slip displacement, and In some cases, the maximum occurred immediately after the occurrence of the sliding displacement. However, the time difference between the time when the slip detection signal Vs becomes maximum and the time when the slip displacement occurs is small, and the time when the slip detection signal Vs becomes maximum may be regarded as the time when the slip displacement occurs.

  As described above, the calculation unit E converts the resistance value of the slip detection unit B into the slip detection signal Vs, and performs the calculation process for obtaining the point in time when the slip displacement becomes the maximum, regardless of the type of the pressing unit 201. The occurrence of slip displacement can be detected. That is, the point in time when the detection signal Vs in the P1 region in FIG. Further, it is possible to detect the occurrence of slippage displacement from the change of the wavelet coefficient obtained by discrete wavelet transform of the high frequency component of the slip detection signal Vs.

  As shown in the P2 region in FIG. 17B, a pre-slip peak where the slip detection signal Vs becomes maximum may occur before the slip displacement occurs. At present, there are cases where a peak before slipping occurs and when it does not occur. However, if the peak before slipping can be reliably detected, it is possible to predict the occurrence of slippage displacement.

  As described above, according to the detection apparatus 100 according to the present embodiment, the following effects can be obtained.

  The detection unit K constituting the detection device 100 is formed by laminating a slip detection unit B that detects the occurrence of slip displacement and an external force detection unit D that detects the magnitude and direction of the external force. In addition to the haptic information, it is possible to detect composite information including slip sensation information that the object to which an external force is applied is stationary or slipping.

  Since the elastic substrate A is installed on the external force acting surface of the detection unit K and the elastic substrate A is deformed at the point of application of the external force F, the point of application of the external force F does not move (slide) and the external force F is accurately received. be able to. Therefore, the external force F is accurately transmitted to the slip detection unit B and the external force detection unit D, and the force information and the slip information can be detected more accurately.

  Since the rigid substrate C is installed under the slip displacement detector B, the slip force detector B does not deform even if the slip detector B has flexibility. Therefore, the external force F is accurately detected by the slip displacement detector B. Act on. Therefore, the slip displacement can be detected more accurately.

  Since the rigid substrate C is installed on the external force detection unit D, the external force F acts on the external force detection unit D not on one point but on the whole. Therefore, the rotational moment of the external force F can be detected from the magnitude (distribution of the external force F) of the external force F acting on the elastic protrusions 32 at a plurality of locations installed in the external force detection unit D and the difference therebetween.

  The slip detection signal Vs in the slip displacement detection unit B has a characteristic that increases and becomes maximum in the vicinity where the slip displacement occurs. Furthermore, since the slip detection signal Vs changes depending on the shape (resistance value) of the pressure-sensitive conductive sheet constituting the slip detection unit B, a change point at which the detection signal Vs becomes maximum regardless of the type of the object is obtained. And the occurrence of slippage displacement can be detected stably.

  If the external force acting on the external force detector D has a force component in the sliding direction (direction parallel to the pressure sensor surface), the center of gravity of the elastic protrusion 32 is displaced from the reference point P and moves in the sliding direction. Then, the ratio of the plurality of pressure sensors S1 to S4 that overlap with the portion where the center of gravity of the elastic protrusion 32 has moved is relatively large, and different pressure values are detected by each pressure sensor. Specifically, a relatively large pressure value is detected by the pressure sensor at a position that overlaps the center of gravity of the elastic protrusion 32, and a relatively small pressure value is detected by a pressure sensor at a position that does not overlap the center of gravity of the elastic protrusion. The Rukoto. Therefore, the difference between the pressure values detected by the pressure sensors S1 to S4 can be calculated by the calculation unit E, and the direction and magnitude of the external force F acting on the external force detection unit D can be obtained based on the difference. .

(Second Embodiment)
Next, the detection apparatus 100 according to the second embodiment will be described. In the present embodiment, the configuration of the external force detection unit D is different from that of the first embodiment, and other configurations are the same. Specifically, the pressure sensor that constitutes the external force detection unit D uses a capacitance type pressure sensor in the first embodiment, but in this embodiment, a resistance type pressure sensor is used. Different.
Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and redundant description is omitted. Hereinafter, the difference from the first embodiment will be mainly described.

<External force detection part D>
FIG. 18 is an exploded perspective view showing a schematic configuration of the external force detection unit D according to the second embodiment. In FIG. 18, reference symbol P denotes a reference point, and reference symbol S denotes a unit detection region detected by a plurality of pressure sensors 42 arranged corresponding to one elastic protrusion 32.
The external force detection unit D includes a substrate having an elastic protrusion 32 that applies an external force F to a reference point, and a resistance type pressure sensor that detects a pressure value of the external force F applied to the reference point. The “reference point” is a point at which the center of an elastic protrusion 32 described later is located when no sliding force is applied.
For convenience of explanation, the pressure sensor 42 and the pressure sensors S1 to S4 may be described with different reference numerals.

As shown in FIG. 18, the external force detection unit D includes a first substrate 101 having a plurality of pressure sensors 42 arranged around the reference point P, a center of gravity located at a position overlapping the reference point P, and a distal end portion due to external force. And a second substrate 30 on which elastic protrusions 32 that are elastically deformed in a state of being in contact with the first substrate 101 are provided.
The first substrate 101 having the pressure sensor 42 is an example of a “first substrate having a pressure sensor”. The second substrate 30 on which the elastic protrusions 32 are formed is an example of “a second substrate on which elastic protrusions are formed”.

  The external force detection unit D calculates the difference between the pressure values detected by the pressure sensors 42 that are arbitrarily combined among the pressure values detected by the plurality of pressure sensors 42 when the elastic protrusion 32 is elastically deformed by the external force. And an arithmetic unit (not shown) that calculates the direction and magnitude of the external force applied based on the difference.

  The first substrate 101 includes a rectangular first substrate body 111 made of a material such as glass, quartz, and plastic, and a plurality of pressure sensors 42 arranged on the first substrate body 111. Has been. For example, the size (size in plan view) of the first substrate body 111 is about 56 mm long × 56 mm wide.

  The plurality of pressure sensors 42 are arranged point-symmetrically with respect to the reference point P. For example, the plurality of pressure sensors 42 are arranged in a matrix in two directions (X direction and Y direction) orthogonal to each other. Thereby, since the distance between the reference point P and each pressure sensor 42 becomes equal to each other, the relationship between the deformation of the elastic protrusion 32 and the pressure value detected by each pressure sensor 42 becomes equal to each other. Therefore, it becomes easy to calculate the difference between the pressure values detected by the pressure sensors 42 arbitrarily combined among the pressure values of the pressure sensors 42. A method for calculating the difference between the pressure values will be described later.

  The interval between the adjacent pressure sensors 42 is about 0.1 mm. For this reason, noise is not applied to the pressure value detected by the pressure sensor 42 at the adjacent position due to the influence of disturbance, static electricity, or the like.

  A plurality of pressure sensors 42 are arranged in a total of four rows and two columns per unit detection area S. The center of the four pressure sensors 42 (the center of the unit detection region S) is the reference point P. For example, the size of the unit detection area S (size in plan view) is about 2.8 mm long × 2.8 mm wide. Further, the areas of the four pressure sensors 42 are substantially equal. The pressure sensor 42 is a pressure-sensitive element using pressure-sensitive conductive rubber. The pressure sensor 42 converts an external force applied to the pressure-sensitive conductive rubber when an external force is applied to the contact surface into an electric signal.

  The second substrate 30 includes a rectangular second substrate body 31 and a plurality of elastic protrusions 32 disposed on the second substrate body 31. The second substrate body 31 is a part that directly receives an external force. The second substrate body 31 can be made of, for example, a material such as glass, quartz, or plastic, or can be made of a resin material such as a urethane foam resin or a silicone resin. In the present embodiment, a resin material is used as a material for forming the second substrate body 31 and the elastic protrusions 32, and the second substrate body 31 and the elastic protrusions 32 are integrally formed with a mold.

  The plurality of elastic protrusions 32 are arranged in a matrix in the X direction and the Y direction on the second substrate body 31. The distal end portion of the elastic protrusion 32 has a spherical weight shape and is in contact with the first substrate 101 (a plurality of pressure sensors 42 on the first substrate body 111). The center of gravity of the elastic protrusion 32 is initially arranged at a position overlapping the reference point P. Further, the plurality of elastic body protrusions 32 are spaced apart from each other. For this reason, it is possible to allow deformation in the direction parallel to the surface of the second substrate body 31 when the elastic protrusion 32 is elastically deformed.

  The size of the elastic protrusion 32 can be arbitrarily set. Here, the diameter of the base of the elastic protrusion 32 (the diameter of the portion where the elastic protrusion 32 contacts the first substrate 101) is about 1.8 mm. The height of the elastic protrusion 32 (the distance in the Z direction of the elastic protrusion 32) is about 2 mm. The spacing between adjacent elastic protrusions 32 is about 2 mm. The durometer hardness of the elastic projection 32 (type A, measured by a durometer conforming to ISO7619) is about 30.

19 and 20 are explanatory diagrams of a method for detecting the direction and magnitude of the external force acting on the reference point P. FIG.
FIGS. 19A to 19C are cross-sectional views showing changes in pressure value by the pressure sensor 42 according to the second embodiment. FIGS. 20A to 20C are plan views showing changes in pressure values by the pressure sensor 42 according to the second embodiment, corresponding to FIGS. 19A to 19C. FIGS. 19A and 20A show a state before an external force is applied to the surface of the second substrate 30 (when no external force is applied). FIG. 19B and FIG. 20B show a state in which an external force in a vertical direction (a state without a sliding force) is applied to the surface of the second substrate 30. FIG. 19C and FIG. 20C show a state where an external force in an oblique direction (with a sliding force) is applied to the surface of the second substrate 30. 20A to 20C, the symbol G indicates the center of gravity (pressure center) of the elastic protrusion 32.

  As shown in FIGS. 19A and 20A, the elastic protrusion 32 is not deformed before an external force is applied to the surface of the second substrate 30. Thereby, the distance between the first substrate 101 and the second substrate 30 is kept constant. At this time, the center of gravity G of the elastic protrusion 32 is disposed at a position overlapping the reference point P. The pressure value of each pressure sensor 42 at this time is stored in a memory (not shown). The direction and magnitude of the external force acting are obtained based on the pressure value of each pressure sensor 42 stored in the memory.

  As shown in FIGS. 19B and 20B, when a vertical external force is applied to the surface of the second substrate 30, the elastic protrusion 32 has the tip portion disposed on the surface of the first substrate 101. In addition, it is compressed and deformed in the Z direction in contact with the plurality of pressure sensors 42. As a result, the second substrate 30 bends in the −Z direction, and the distance between the first substrate 101 and the second substrate 30 becomes smaller than when there is no external force. The pressure value of the pressure sensor 42 at this time becomes larger than when there is no external force. The amount of change is substantially the same for each pressure sensor 42.

  As shown in FIGS. 19C and 20C, when an external force in an oblique direction is applied to the surface of the second substrate 30, the elastic protrusion 32 has the tip portion disposed on the surface of the first substrate 101. In a state where the pressure sensor 42 is in contact with the plurality of pressure sensors 42, the pressure sensor 42 is inclined and compressed and deformed. As a result, the second substrate 30 bends in the −Z direction, and the distance between the first substrate 101 and the second substrate 30 becomes smaller than when there is no external force. At this time, the center of gravity G of the elastic protrusion 32 is shifted from the reference point P in the + X direction and the + Y direction. In this case, the overlapping areas of the tip of the elastic protrusion 32 and the four pressure sensors 42 are different from each other. Specifically, the area where the tip of the elastic protrusion 32 overlaps with the four pressure sensors 42 is larger in the + X direction than the area where the four pressure sensors 42 overlap with the portions arranged in the −X direction and the −Y direction. And the area which overlaps with the part arrange | positioned at + Y direction becomes larger.

The elastic protrusion 32 is biased in deformation by an external force in an oblique direction. That is, the center of gravity of the elastic protrusion 32 is displaced from the reference point P and moves in the sliding direction (X direction and Y direction). Then, each pressure sensor 42 detects a different pressure value. Specifically, a relatively large pressure value is detected by the pressure sensor 42 at a position overlapping the gravity center of the elastic protrusion 32, and a relatively small pressure value is detected by the pressure sensor 42 at a position not overlapping with the gravity center of the elastic protrusion 32. Will be detected. And the direction and magnitude | size to which the external force acted are calculated | required based on the calculation method of the difference mentioned later.
<Calculation unit E related to external force detection>

  The external force detection unit D shown in FIG. 18 is detected by each pressure sensor arbitrarily combined among the pressure values detected by the four pressure sensors S1 to S4 as the elastic protrusion 32 is elastically deformed by an external force. The difference between the pressure values is calculated, and the direction in which the external force is applied is calculated based on the difference.

  The second embodiment and the first embodiment are the same in the arrangement of the pressure sensor, the output value of the pressure sensor, and the like, except for the method of the pressure sensor. Further, since the direction and magnitude of the external force applied under the same conditions as in the first embodiment were obtained, the same drawings as in the first embodiment, that is, FIG. 13 (a diagram showing a coordinate system of the sensing area), FIG. Details of the calculation method for obtaining the direction in which the external force is applied will be described with reference to FIG. 15 (an example of the calculation of the sliding direction by the pressure sensor).

As shown in FIG. 13, a plurality of pressure sensors S <b> 1 to S <b> 4 are arranged in a unit of two vertical rows and two horizontal columns per unit detection region S. Here, when the pressure values (detected values) detected by the pressure sensors S1 to S4 are P _S1 , P _S2 , P _S3 , and P _S4 , the X direction component Fx of the external force (X of the in-plane direction components of the external force) The ratio of the component force acting in the direction) is expressed by the following equation (5) similar to the first embodiment.

  Further, the Y direction component Fy of the external force (the ratio of the component force acting in the Y direction among the in-plane direction components of the external force) is also expressed by the following equation (6) similar to the first embodiment.

  Further, the Z direction component Fz of the external force (vertical direction component of the external force) is also expressed by the following equation (7) similar to the first embodiment.

  As shown in Expression (5), in the X-direction component Fx of the external force, the values detected by the pressure sensors S2 and S4 arranged in the + X direction among the pressure values detected by the four pressure sensors S1 to S4 are as follows. In addition, the values detected by the pressure sensors S1 and S3 arranged in the −X direction are combined. As described above, the X direction component of the external force is based on the difference between the pressure value obtained by the combination of the pressure sensors S2 and S4 arranged in the + X direction and the pressure value obtained by the combination of the pressure sensors S1 and S3 arranged in the -X direction. Desired.

  As shown in Expression (6), in the Y direction component Fy of the external force, the values detected by the pressure sensors S1 and S2 arranged in the + Y direction among the pressure values detected by the four pressure sensors S1 to S4 are as follows. The values detected by the pressure sensors S3 and S4 arranged in the −Y direction are combined together. Thus, the Y direction component of the external force is based on the difference between the pressure value obtained by the combination of the pressure sensors S1 and S2 arranged in the + Y direction and the pressure value obtained by the combination of the pressure sensors S3 and S4 arranged in the -Y direction. Desired.

  As shown in the equation (7), the Z direction component Fz of the external force is obtained by a resultant force obtained by adding the pressure values of the four pressure sensors S1 to S4. However, the Z direction component Fz of the external force tends to be detected with a larger detection value than the X direction component Fx of the external force and the Y direction component Fy (component force) of the external force. For example, when a hard material is used as the material of the elastic protrusion 32 or the shape of the tip is sharpened, the detection sensitivity of the Z-direction component Fz of the external force increases. However, if a hard material is used as the material of the elastic protrusion 32, the elastic protrusion 32 is not easily deformed, and the detected value of the external force in the in-plane direction becomes small. Further, when the shape of the tip of the elastic protrusion 32 is sharpened, a strong sensitivity (uncomfortable feeling) may be given to the touch feeling when the contact surface is touched with a finger. For this reason, in order to align the detected value of the Z direction component Fz of the external force with the detected value of the X direction component Fx and the Y direction component Fy of the external force, detection is performed with a correction coefficient determined by the material and shape of the elastic protrusion 32. It is necessary to correct the value appropriately.

As shown in FIG. 14, a case is considered in which the upper left position of the detection surface of the external force detection unit D (the surface on which the external force acts on the elastic substrate A) is obliquely pushed with a finger. In the external force detection unit D, unit detection areas S are arranged in a matrix of 15 rows × 15 columns (225 in total). That is, a rectangular grid surrounded by a solid line in FIG. 14 is a unit detection region S, and each unit detection region S includes four pressure sensors S1 to S4 (not shown) in two rows and two columns.
At this time, the pressure in the vertical direction of the external force is greatest at the central portion of the portion where the external force is applied (about 90 to 120 mV). Moreover, the pressure in the vertical direction of the external force decreases in the order of the peripheral portion (about 60 to 90 mV) and the outermost peripheral portion (about 30 to 60 mV) next to the central portion. Moreover, the area | region which is not pressed with the finger | toe is about 0-30 mV.

  As shown in FIG. 15, a method for calculating an in-plane direction component (slip direction) of external pressure when a position closer to the upper left than the center of the detection surface of the external force detection unit D is obliquely pressed with a finger will be considered. The finger pressing force (external force) acts on the unit detection areas S of the unit detection areas S arranged in 15 rows × 15 columns arranged in 3 rows × 3 columns. To do.

FIG. 15A shows the total value (P _S1 + P _S2 + P _S3 + P _S4 ) of the detection values of the four pressure sensors S1 to S4 in the unit detection region S where an external force is applied. FIG. 15B shows the detected values (P _S1 , P _S2 , P _S3 , P _S4 ) of the four pressure sensors S1 to _S4 in the unit detection area for each unit detection area S. Further, the solid line in FIG. 15B indicates the boundary of the unit detection region S, and the dotted line indicates the boundary of the pressure sensors S1 to S4. FIG. 15C shows the layout and coordinate system of the four pressure sensors S1 to S4 arranged in the unit detection region S surrounded by the dotted line Q in FIG. Moreover, as shown in FIG.15 (c), the detected value of pressure sensor S1- _S4 becomes _PS1- PS4. The four pressure sensors S1 to S4 in the other unit detection areas S in FIG. 15B also have the same layout and coordinate system. FIG. 15D shows, for each unit detection area S, the X-direction component Fx of the external force and the Y-direction component Fy of the external force obtained by the above-described equations (5) and (6).

The direction in which the external force acts is determined by, for example, a method of obtaining an average value of nine calculation results shown in FIG. 15D, for example, a maximum value (for example, a detection value larger than a predetermined threshold value) among the nine calculation results. It can be obtained using a method for obtaining it. Here, the nine calculation results shown in FIG. 15D are averaged to obtain the X direction component Fx of the external force and the Y direction component Fy of the external force. The external force is about 123 ° counterclockwise with respect to the + X direction. It can be seen that it is acting in the direction of.
Thus, each unit detection area S arranged in 3 vertical rows by 3 horizontal columns has four pressure sensors S1 to S4, and among the detection values detected by the pressure sensors S1 to S4, respectively. A difference between detection values of the pressure sensors S1 to S4 arbitrarily combined is calculated, and a direction in which an external force is applied is calculated based on the difference.

  As described above, according to the detection apparatus 100 according to the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

The external force detection unit D is in a sliding direction (a direction parallel to the surface of the pressure sensor 42) in a state where the tip of the elastic protrusion 32 formed on the second substrate 30 is in contact with the first substrate 101 (the plurality of pressure sensors 42). Therefore, the detection accuracy of the direction and magnitude of the external force can be increased.
Specifically, when an external force is applied to the surface of the second substrate 30, the elastic protrusions 32 are compressed and deformed in a state where the tip portions are in contact with the plurality of pressure sensors 42 arranged on the first substrate 101. At this time, when there is a sliding force component in a predetermined direction in the surface, the elastic protrusion 32 is biased in deformation. That is, the center of gravity of the elastic protrusion 32 is shifted from the reference point P and moves in a predetermined direction (slip direction). As a result, the ratio of the plurality of pressure sensors 42 overlapping the portion where the center of gravity of the elastic protrusion 32 has moved becomes relatively large. That is, different pressure values are detected by the pressure sensors S1 to S4. Specifically, a relatively large pressure value is detected by the pressure sensor 42 at a position overlapping the gravity center of the elastic protrusion 32, and a relatively small pressure value is detected by the pressure sensor 42 at a position not overlapping with the gravity center of the elastic protrusion 32. Will be detected. Therefore, it is possible to calculate the difference between the pressure values detected by the pressure sensors S1 to S4 by the calculation device, and obtain the direction and magnitude in which the external force is applied based on the difference. Therefore, it is possible to provide the detection device 100 capable of detecting the direction and magnitude of the external force with high accuracy.

  Since the pressure sensor 42 arranged in the external force detection unit D is composed of pressure-sensitive conductive rubber having excellent flexibility, it is possible to obtain an effect of being strong against mechanical stress such as impact.

  In addition, the pressure sensor 42 arrange | positioned in the external force detection part D is not limited to an electrostatic capacitance system and a resistance system. For example, a charge change method using a piezo effect that generates a charge on the crystal surface when pressure is applied to the ferroelectric crystal may be used. For example, an optical system such as a change in light reflectance due to deformation of an elastic body or displacement measurement of a marker in the elastic body may be used. Further, for example, a mechanical displacement method that detects from a displacement or deformation of a mechanical structure such as a spring may be used. In short, any element can be used as long as it can detect a physical quantity that varies with pressure as an electrical signal.

(Third embodiment)
(Electronics)
FIG. 21 is a schematic diagram illustrating a schematic configuration of a personal digital assistant (PDA) 2000 as an electronic apparatus to which the detection device 100 according to the first embodiment and / or the second embodiment is applied. The portable information terminal 2000 includes a liquid crystal panel 2001 to which a plurality of operation buttons 2002, a power switch 2003, and a detection unit K as a display unit are applied. When the power switch 2003 is operated, a menu button is displayed on the liquid crystal panel 2001. For example, when a menu button (not shown) is touched with a finger, various games are displayed or an electronic blackboard is displayed.

  According to such an electronic device, since the above-described detection device 100 is provided, in addition to the haptic information of the direction and magnitude of the external force, slip information such as stillness and slip is used to operate the electronic device. It can be captured as input information. For example, when a sliding displacement occurs due to an operation with a finger, by changing the lighting color of the backlight (not shown) of the liquid crystal panel 2001, it is possible to increase the variety of games for amusement applications.

  In addition to information portable terminals, electronic devices include, for example, cellular phones, personal computers, video camera monitors, car navigation devices, pagers, electronic notebooks, calculators, word processors, workstations, videophones, POS terminals, digital stills. Examples of the device include a touch panel such as a camera. The detection apparatus 100 according to the above embodiment can also be applied to these electronic devices.

(Fourth embodiment)
(robot)
FIG. 22 is a schematic diagram illustrating a schematic configuration of a robot hand 3000 as a robot to which the detection device 100 according to the first embodiment and / or the second embodiment is applied. As shown in FIG. 22A, the robot hand 3000 includes a main body 3003, a pair of arms 3002, and a grip 3001 to which the detection device 100 is applied. For example, when a drive signal is transmitted to the arm unit 3002 by a control device such as a remote controller, the pair of arm units 3002 open and close.

  As shown in FIG. 22B, consider a case in which an object (target object) 3010 such as a cup is held by the robot hand 3000. At this time, the force acting on the object 3010 is detected as pressure by the gripping unit 3001. Since the robot hand 3000 includes the detection device 100 described above as the gripping unit 3001, a force in a direction sliding with gravity Mg in addition to a force in a direction perpendicular to the surface (contact surface) of the object 3010 (slip force component). Can be detected. For example, it can be held while adjusting the force according to the texture of the object 3010 so as not to deform a soft object or drop a slippery object.

  According to this robot, the force applied to the object can be appropriately controlled not only when the object is stationary, but also when the object is slipping. Can provide more human-like movements, such as, for example, an action that cares for a person (boiling, rubbing, wiping), for example, an craftsman-like action of processing a flexible material such as clay with an appropriate force .

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

(Modification 1)
In order from the side on which the external force acts, the detection unit K according to the first embodiment includes an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D stacked. In the detection unit K, the elastic substrate A, the slip detection unit B, the rigid substrate C, the external force detection unit D, and the rigid substrate C are stacked.

  By adopting such a configuration, since the rigid substrate C is also installed on the surface opposite to the surface on which the external force of the external force detection unit D acts, the external force detection unit D is deformed even if the external force is applied, There is no false detection of the direction of the acting external force. Furthermore, the effect that the detection part K can be attached also to the flexible object which is easy to deform | transform can also be acquired.

(Modification 2)
In order from the side on which the external force acts, the detection unit K according to the first embodiment includes an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D stacked. In the detection unit K, the elastic substrate A, the slip detection unit B, and the external force detection unit D are stacked, and the electrode sheet B2 forming the pair of electrodes of the slip detection unit B or the elastic protrusion 32 of the external force detection unit D is provided. At least one of the formed second substrates 30 is formed of a rigid substrate such as glass, ceramic, metal, or resin.

  With this configuration, since at least one of the slip detection unit B or the external force detection unit D has a rigid substrate, the rigid substrate C is interposed between the slip detection unit B and the external force detection unit D. Even if it does not install, the effect that the slip detection part B and the external force detection part D can be functioned appropriately can be acquired.

(Modification 3)
In order from the side on which the external force acts, the detection unit K according to the first embodiment includes an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D stacked. In the detection unit K, an elastic substrate A, an external force detection unit D, a slip detection unit B, and a rigid substrate C are stacked.

  Even with such a configuration, the external force detection unit D can detect the haptic information of the direction and magnitude of the external force, and the slip detection unit B can detect the combined information of slippage information of stationary or slipping. Can be obtained.

(Modification 4)
In order from the side on which the external force acts, the detection unit K according to the first embodiment includes an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D stacked. In the detection unit K, the elastic substrate A, the external force detection unit D, and the slip detection unit B are stacked.

  With such a configuration, when the detection unit K is attached to a rigid object, the detection unit can be installed without installing a rigid substrate on the surface opposite to the surface on which the external force of the slip detection unit B acts. Since the object to which K is attached has rigidity, the slip detection unit B can accurately detect slip sensation information that the object is stationary or slipped without being deformed by an external force. Furthermore, since the rigid board | substrate C can be abbreviate | omitted, the effect that the detection part K can be manufactured more cheaply can also be acquired.

(Modification 5)
In order from the side on which the external force acts, the detection unit K according to the first embodiment includes an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D stacked. In the detection unit K, the elastic substrate A, the external force detection unit D, the rigid substrate C, the slip detection unit B, and the rigid substrate C are stacked.

  By adopting such a configuration, the rigid substrate C is installed on the surface opposite to the surface on which the external force of the external force detection unit D acts. The direction of external force to be detected is not erroneously detected. Furthermore, since the rigid substrate C is also installed on the surface opposite to the surface on which the external force acts on the slip detection unit B, the slip detection unit B will not be deformed even if an external force is applied. A predetermined external force acts on the. Therefore, slip information such as stillness or slip can be accurately detected in the slip detection unit B. Furthermore, the effect that the detection part K can be attached also to the flexible object which is easy to deform | transform can also be acquired.

(Modification 6)
In order from the side on which the external force acts, the detection unit K according to the first embodiment includes an elastic substrate A, a slip detection unit B, a rigid substrate C, and an external force detection unit D stacked. In the detection unit K, the elastic substrate A, the external force detection unit D, and the slip detection unit B are stacked, and the electrode sheet B2 that forms a pair of electrodes of the slip detection unit B is made of glass, ceramic, metal, resin, or the like. It is comprised with the board | substrate which has rigidity.

  By adopting such a configuration, the slip detection unit B has rigidity, so that it does not deform even when an external force is applied, and a predetermined external force is applied. Therefore, it is possible to obtain an effect that the slip detection unit B can accurately detect slip sense information such as still or slip. Furthermore, the effect that the detection part K can be attached also to the flexible object which is easy to deform | transform can also be acquired.

(Modification 7)
In the above-described Modification 3 to Modification 6, the second substrate 30 on which the elastic protrusion 32 of the external force detection unit D is formed is configured by a substrate having rigidity such as glass, ceramic, metal, or resin.

  By adopting such a configuration, the second substrate 30 of the external force detection unit D has rigidity, so that the external force acts on the elastic protrusions 32 of the external force detection unit D not at one point but at a plurality of locations. Therefore, it is possible to obtain an effect that the rotational moment of the external force can be detected from the magnitude of the external force (external force distribution) applied to the elastic protrusions 32 at a plurality of locations and the difference therebetween.

  A: elastic substrate, B: slip detection unit, C: rigid substrate, D: external force detection unit, E: calculation unit, F: external force, Fs: external force in the sliding direction, K: detection unit, B1: pressure sensitive conductive sheet, B2 ... electrode sheet, B1a ... non-conductive elastomer resin, B1b ... conductive particles, P ... reference point, S ... unit detection region, 10 ... first capacitance electrode substrate, 20 ... second capacitance electrode substrate, 30 ... second Substrate, 32 ... elastic projection, 40 ... dielectric, 100 ... detection device, 101 ... first substrate, 200 ... experimental device, 201 ... pressing member, 202 ... gripping member, 203 ... cart, 2000 ... portable information terminal (electronic) Equipment) 3000 ... Robot Hand (Robot)

Claims (16)

Having a surface on which an external force acts,
An external force detector for detecting the direction and magnitude of the external force;
A slip detection unit for detecting a slip displacement generated by the external force,
The external force detector is
A first substrate having a plurality of pressure sensors arranged around a reference point;
A center of gravity located at a position overlapping with the reference point, and a second substrate on which an elastic protrusion is formed that elastically deforms in a state where a tip portion is in contact with the first substrate by the external force, and
The slip detector is
A pressure-sensitive conductive sheet;
And a third substrate electrically connected to the pressure-sensitive conductive sheet and provided with a pair of electrodes for detecting a resistance value of the pressure-sensitive conductive sheet.   The detection device according to claim 1, wherein a substrate having elasticity is installed on a surface on which the external force acts.   The detection device according to claim 1, wherein at least one of a concave portion and a convex portion is formed on the surface on which the external force acts.   The detection according to any one of claims 1 to 3, wherein the third substrate, the second substrate, and the first substrate are stacked in order from the side on which the external force acts. apparatus.   The detection apparatus according to claim 4, wherein a rigid substrate is installed between the third substrate and the second substrate.   The detection apparatus according to claim 4, wherein the external force detection unit configured by the second substrate and the first substrate is sandwiched between a pair of rigid substrates.   The detection apparatus according to claim 4, wherein at least one of the second substrate and the third substrate is a rigid substrate.   4. The detection according to claim 1, wherein the second substrate, the first substrate, and the third substrate are laminated in order from the side on which the external force acts. apparatus.   The detection apparatus according to claim 8, wherein a rigid substrate is installed on a surface of the third substrate opposite to the surface on which the external force acts.   The detection apparatus according to claim 8, wherein the third substrate is sandwiched between a pair of rigid substrates.   The detection apparatus according to claim 8, wherein the third substrate is a rigid substrate.   The detection device according to claim 8, wherein the second substrate is a rigid substrate. The detection device includes a calculation unit,
The calculation unit calculates a difference between pressure values detected by the pressure sensors arbitrarily combined among pressure values detected by the plurality of pressure sensors as the elastic protrusions are elastically deformed by the external force. The detection device according to claim 1, wherein a calculation process for obtaining a direction in which the external force is applied and a magnitude of the external force is executed based on the difference.   The said calculating part converts the resistance value of the said pressure sensitive conductive sheet into a slip detection signal, and performs the calculation process which detects generation | occurrence | production of the said slip displacement from the change of the said slip detection signal, It is characterized by the above-mentioned. The detection device described.   An electronic apparatus comprising the detection device according to claim 1.   A robot comprising the detection device according to claim 1.

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