JP7476624B2 - Vibration response sensor, robot hand, and specimen determination device - Google Patents

Description

The present invention relates to a vibration response sensor, a robot hand, and a specimen evaluation device.

In the past, in order to allow robotic hands to stably grasp fragile materials or materials with irregular shapes, attempts have been made to make the exterior of the robotic hand deformable so that it can grasp materials of various shapes. Such robotic hands are called soft robots (for example, Patent Document 1).

For stable gripping, a method is known in which several thousand electrical resistance type pressure sensors are attached tightly to the surface of a robot hand and the contact pressure with the surface of the object to be gripped is analyzed using AI (for example, Non-Patent Document 1). In addition to electrical resistance type pressure sensors, it has also been proposed to incorporate drive mechanisms that use deformation tension of dielectric elastomers, thread tension, air pressure, or hydraulic pressure as sensors for use in robot hands (for example, see Non-Patent Document 2).

U.S. Pat. No. 9,464,642

Nature562, 698-702 Journal of the Robotics Society, Vol. 37, No. 1, 2019

One idea is to use a camera or other device to recognize the shape of the object to be grasped from an image. In this case, it is required that there are no obstacles between the camera and the object to be grasped. Also, a significant amount of learning is required to predict the hardness and amount of deformation from the image and grasp the object. Even with a significant amount of learning, it may be possible to predict the approximate properties, but it is difficult to predict the actual hardness or weight of the material, and there is a risk that the material cannot be grasped stably.

By installing multiple sensors on a robot hand, it is possible to measure the hardness and weight of an object. However, there is a problem in that the information from the multiple sensors needs to be analyzed, which requires a large-scale and highly advanced computing power for the computer performing the analysis. In addition, wiring extends from the multiple sensors installed on the robot hand. Since the robot hand moves, the wiring needs to have a certain degree of strength. There is also the problem that increasing the strength makes the wiring thicker and bulkier.

In addition, soft robots can prevent excessive force from being applied to the material being grasped by deforming the exterior of the robot hand according to the shape of the material being grasped. However, the deformation of the exterior does not mean that the material is grasped with a force appropriate for the material, and there is a risk that the material may be destroyed or slip off depending on how it is grasped.

The objective of the conventional technology is to provide a vibration response sensor, a robot hand, and a specimen evaluation device that can identify the hardness of an object, the presence or absence of an edge, etc., with a simple structure.

As a result of intensive research, the inventors of the present application discovered that a vibration response sensor is provided in the gripping section, and the gripping state of the gripping section is controlled based on a signal from the vibration response sensor. In addition, in order to determine whether a gripped object is good or bad based on the signal from the vibration response sensor, they discovered that there is a correlation between the hardness or size of the material and the signal output by the sensor in a resonant state between the gripped material and the sensor in response to vibration, and arrived at the disclosure of the present application.

The inventors of the present application have also discovered that by using a film-shaped frictional or electret-type power generating charged sensor as a vibration response sensor, it is possible to obtain more detailed information than with a conventional pressure sensor using a piezoelectric element. Examples of the present invention include a robot capable of properly gripping an object to be gripped. Examples of the present invention also include analysis of the physical properties of a gripped material, such as hardness and resilience, and shape information, such as size, using a surface-contact type vibration response sensor that is simple and has little wiring. Examples of the present invention are as follows.

[1] A sensor body having a contact surface to be brought into contact with a sample;
a vibrator that supplies vibration to the specimen or the sensor body in a contact state in which the contact surface is in contact with the specimen;
an extraction unit that extracts a response signal indicating a response to the supply of the vibration from an electrode included in the sensor body;
1. A vibration response sensor comprising:

[2] The vibration response sensor described in [1], in which the sensor body is an electrostatic sensor.

[3] The vibration response sensor described in [2], in which the charged sensor body has a structure in which two charged members, each including the electrode and a dielectric layer, are stacked with a gap therebetween.

[4] The vibration response sensor described in [3], in which the dielectric layer is formed from a resin film.

[5] The vibration response sensor according to any one of [1] to [4], wherein the vibrator supplies vibration to a surface of the sensor body opposite the contact surface.

[6] The vibration response sensor according to any one of [1] to [5], in which the vibrator applies and releases pressure to the specimen or a predetermined surface of the sensor body by moving back and forth.

[7] A gripping portion,
A robot hand comprising: a vibration response sensor according to any one of [1] to [6] attached to the gripping portion.

[8] A vibration response sensor according to any one of [1] to [6],
and a determination circuit that determines the physical properties of the sample or the contact state of the sensor body with the sample based on the waveform shape of the response signal, the level of which increases or decreases in response to the supply of pressure to the sample by the transducer and the release of the supply of pressure.

[9] The specimen determination device described in [8], in which the determination circuit determines the hardness of the specimen based on the magnitude of the level of the response signal.

[10] The apparatus for determining the elasticity of the specimen according to [8] or [9], wherein the determination circuit determines the elasticity of the specimen based on the decay time of the level of the response signal associated with the release of the pressure.

[11] The determination circuit determines whether the contact surface of the sensor body is in contact with the edge of the specimen based on whether or not a level of the response signal at the start of the supply of the pressure is attenuated.
The determination device according to any one of [8] to [10].

According to an embodiment of the present invention, it is possible to identify the hardness of a specimen using a simple configuration.

FIG. 1 is a diagram showing an example of the configuration of a vibration response sensor. FIG. 2A is a top view of the vibration responsive sensor, and FIG. 2B is a bottom view of the vibration responsive sensor. FIG. 3 is a diagram showing the characteristics of the analyte, the signal indicative of pressure, and the characteristics of the response signal. FIG. 4 shows an example of a robot hand (gripping portion) to which a vibration response sensor is applied. FIG. 5 shows a vibration response sensor mounted on the grip. FIG. 6 is a diagram showing an example of a pressure waveform and a response signal obtained by supplying pressure. FIG. 7 is a block diagram showing an example of the configuration of a specimen determination device according to an embodiment. FIG. 8 is a table showing an example of the determination information. FIG. 9 is a flowchart showing an example of a process for determining hardness and a specimen type. FIG. 10 is a flowchart showing an example of a sample determination process.

The present invention will be described in detail below. The following description is an example of the present invention, and the present invention is not limited to these details as long as it does not exceed the gist of the invention.

One aspect of the present invention is a vibration response sensor. The vibration response sensor includes a sensor body having a contact surface that is brought into contact with a specimen, a vibrator that supplies vibrations to the specimen or the sensor body when the contact surface is in contact with the specimen, and an extraction unit that extracts a response signal indicating a response to the supply of vibration from an electrode provided in the sensor body.

(Specimen)
The "specimen" is an object (solid) that comes into contact with the contact surface of the sensor, and there is no restriction on its material or shape. Examples of the specimen include metal plates such as aluminum, zinc, copper, or steel, plates made of paper, rubber, plastic film, or glass, blocks, flowerpots, sheets, tableware, desks, containers, gloves, bags, and other molded products, foods such as mandarin oranges, bananas, rice, bread, konjac, and meat, insects, animals, and fish, and at least one of these examples can be selected as the specimen.

(Sensor body)
The type of the sensor body is not particularly limited. For example, a resin thin film electrical resistance pressure sensor such as silicone rubber, a piezo-resistance sensor, an optical fiber sensor, an electrostatic sensor (electrostatic film sensor), etc. may be applied as the sensor body. The piezo-resistance sensor is a piezo-resistance pressure sensor that utilizes the piezoelectric effect. The optical fiber sensor is an optical fiber tactile sensor that has optical fibers with different core diameters and detects bending as optical loss. The piezo-resistance sensor has low sensor sensitivity but is cost-effective. The optical fiber sensor requires a separate light-emitting device, but is more sensitive than the piezo-resistance sensor, making it preferable to apply it to the sensor body.

The charged sensor does not require a power source and the signal strength (level) is zero-based when not sensing. This results in a high signal-to-noise ratio (sensitivity) when the signal output from the charged sensor is amplified by an amplifier. Therefore, the response to vibration can be detected with high accuracy from the output signal of the charged sensor. For this reason, it is particularly preferable to use the charged sensor as a "sensor" that is applied to a vibration response sensor.

In this specification, an electrified sensor is a sensor that utilizes the electrification principle of frictional power generation or electrets. An electrified sensor generates voltage by itself by utilizing the principle of electrified power generation. For this reason, no light-emitting device or power source is required. For this reason, the structure is simpler than optical fiber sensors that detect responses by fluctuations in a constant light or electrical signal, and it is less susceptible to the effects of external disturbances.

The charging sensor has a friction charging structure or an electret charging structure. A friction charging structure has a structure in which two (a pair of) charging members face each other, that is, two charging members each including an electrode and a dielectric layer are stacked (facing each other) with a gap between them. An electret charging structure has a structure in which a pair of charging members consisting of an electrode and a dielectric layer has a dielectric layer having multiple positively and negatively charged bubbles sandwiched between electrodes. A charging sensor having a friction charging structure is called a friction charging sensor, and a charging sensor having an electret charging structure is called an electret charging sensor.

When vibration stimuli are repeatedly applied to the frictional charging structure or the electret charging structure, the structure of the dielectric layer in each of the frictional charging structure and the electret charging structure is deformed, and the charge capacitance between the electrodes changes. For example, in a frictional charging sensor, friction occurs between the charged members when vibrations are supplied by the vibrator, and the charge capacitance between the electrodes changes. A potential difference occurs between the two electrodes as the charge capacitance changes. By measuring this potential difference, the charging sensor operates as a sensor that detects the vibration response.

(Dielectric Layer)
The material of the dielectric layer is not particularly limited as long as it is a material having electrostatic properties. For example, polymers (resins) and non-metallic substances can be mentioned. Examples of polymers include silicone resins (polydimethylsiloxane (PDMS) and the like), fluororesins (polytetrafluoroethylene (PTFE) and the like), polyimide, polyvinyl chloride, polystyrene, polyolefins (polyethylene, polypropylene and the like), polyester resins (polyethylene terephthalate (PET) and the like), polycarbonate resins, acrylic resins (polymethyl methacrylate (PMMA) and the like), polyamide resins (nylon and the like), and cellulose. Examples of non-metallic substances include oxides such as silica and alumina. The dielectric layer is preferably formed of a resin film or a thin film of a non-metallic substance in order to reduce the size and thickness of the vibration response sensor.

The dielectric constant (εDI) of the dielectric layer is preferably 5 or more, more preferably 8 or more. There is no upper limit to the dielectric constant of the dielectric layer, but a higher value is preferable. The dielectric constant can be calculated from the following formula 1 by forming electrodes on both sides of a layer of the material to be measured (specimen) to prepare a parallel plate capacitor and measuring the capacitance C of the capacitor.
C=ε0·εr·A/d (Equation 1)
Here, εr is the relative dielectric constant, ε0 is the dielectric constant of a vacuum, A is the area of the capacitor, and d is the film thickness of the layer of the material to be measured. The capacitance C of the capacitor can be measured using an LCR meter, an impedance analyzer, or the like.

The portion of the dielectric layer that comes into contact with and generates friction during vibration supply is preferably made of the following materials as the outermost layer. That is, examples of the material for the outermost layer include polymers, nonmetallic substances, and metallic substances. Examples of polymers include those mentioned above, as well as melamine resin. Examples of nonmetallic substances include oxides such as silica and alumina. Examples of metallic substances include aluminum, iron, nickel, silver, gold, platinum, copper, chromium, titanium, molybdenum, and indium metal, as well as alloys of these metals.

(electrode)
The electrodes are not particularly limited as long as they are made of a material having high electrical conductivity, and can be suitably used. The electrodes are, for example, aluminum, iron, nickel, silver, gold, platinum, copper, chromium, titanium, molybdenum, and indium metal, and alloys of these metals can also be used. The electrodes do not have to be made of metal as long as they have high electrical conductivity. The electrodes can be made of, for example, semiconductor materials such as doped silicon (Si), metal oxides such as indium tin oxide (ITO), and conductive polymers such as PEDOT-PSS. The electrodes are preferably made of a material that is soft, deformable, and resistant to damage, and are preferably made as thin as possible within a range that can be used in practical use, usually 100 μm or less, more preferably 50 μm or less, and most preferably 25 μm or less, with a lower limit of 10 μm or more. By making the electrodes such a thin thickness, it is possible to prevent malfunctions due to electrode damage without reducing the sensitivity of the vibration response sensor.

(Transducer)
The vibrator may be any vibrator that applies vibration to an appropriate position on the specimen or the sensor body. For example, it is preferable that the vibrator is configured to supply vibration to the surface of the sensor body opposite to the contact surface. However, the position of the vibration supply is not limited to the opposite surface. It is preferable that the vibrator supplies vibration stimulation to the specimen or the sensor body by, for example, repeatedly supplying and releasing pressure to the specimen or the sensor body.

Furthermore, the transducer has the function of fixing the shape and area of the surface that comes into contact with and applies pressure to the specimen. By changing the shape and area of the surface as necessary and applying vibration to the specimen, a vibration response is observed from the specimen in accordance with the changes in the shape and area of the surface. This makes it possible to obtain information about the shape and size of the specimen.

The vibrator may be, for example, the iron core of a solenoid in a robot hand to which a constant-period pulse is applied. Alternatively, a string-like object such as a thread may be wound around the rotating shaft of a cam, and the cam may rotate when the string-like object is pulled, causing a cam follower (such as a weight) to perform a predetermined operation (such as up and down movement) as a vibrator to provide vibration. A cam that transmits pressure to the vibrator may be attached to a motor (such as a servo motor), and the vibrator provided in the gripping part may be vibrated by rotating the motor forward and backward. Furthermore, a type of vibrator that applies pressure (vibration) non-contact by spraying high-pressure air or liquid such as water using a thin nozzle may also be used.

(Removal part)
The output unit outputs a response signal to the vibration from the electrodes of the sensor body. When the response signal is an electrical signal, the output unit is configured using a conductor. For example, the output unit is a lead wire, a terminal, a connector, or the like electrically connected to the electrodes.

(Robot hand)
One embodiment of the present invention is a robot hand. The robot hand includes, for example, a gripping unit (hand) and a vibration response sensor attached to the gripping unit via a support member. The vibration response sensor is provided in a contact portion with an object to be grasped (for example, a hand or a finger pad) so that a contact surface of the vibration response sensor comes into contact with the object to be grasped during a gripping operation of the gripping unit.

(Sample determination device)
One embodiment of the present invention is a device for determining a specimen. The device includes a vibration response sensor and a determination circuit for determining the physical properties of the specimen or the contact state of the sensor body with the specimen based on the shape of a waveform of a response signal whose level increases or decreases in response to the supply of pressure to the specimen by a vibrator and the release of the pressure supply. The determination circuit is preferably configured to determine the hardness of the specimen based on the magnitude of the signal level of the response signal. The determination circuit is preferably configured to determine the elasticity of the specimen based on the attenuation time of the level of the response signal associated with the release of the pressure supply. The determination circuit is preferably configured to determine whether the contact surface of the sensor is in contact with the edge of the specimen based on the presence or absence of attenuation of the level of the response signal at the start of the pressure supply.

The following describes an embodiment of the present invention with reference to the drawings. The configurations of the following embodiments are examples, and the present invention is not limited to the configurations of the embodiments.

<Vibration response sensor>
Fig. 1 is a diagram showing an example of the configuration of a vibration responsive sensor 40, Fig. 2A is a plan view of the vibration responsive sensor 40, and Fig. 2B is a bottom view of the vibration responsive sensor 40. Fig. 1 is a schematic diagram showing a cross section taken along line AA shown in Fig. 2A.

The vibration response sensor 40 comprises a sensor body 41, a vibrator 42, and lead wires 43A and 43B as response signal output sections. The sensor body 41 comprises a charged member 51A, a charged member 51B, and a spacer 55. Each of the charged members 51A and 51B has a planar rectangular film shape, and is bonded, pressed, or fused to the rectangular frame-shaped spacer 55 while facing each other with the spacer 55 in between. As a result, a gap 44 (unbonded portion) is formed in the center of the opposing charged members 51A and 51B.

The charged member 51A has a layered structure of, from the top, a support (protective layer) 54A, an electrode 53A, and a dielectric layer 52A. The charged member 51B has a layered structure of, from the top, a dielectric layer 52B, an electrode 53B, and a finger support (protective layer) 54B. In this way, the dielectric layer 52A and the dielectric layer 52B face each other. The dielectric layer 52A and the dielectric layer 52B come into contact when vibration is supplied, generating friction and generating electricity.

In the example shown in FIG. 1, each of the charging members 51A and 51B is formed in a rectangular shape of 18 mm x 18 mm. Each of the support 54A and the dielectric layer 52A is formed using a polyethylene terephthalate (PET) film with a thickness of 16 μm. Each of the electrode 53A, the dielectric layer 52B, and the electrode 53B is an aluminum film with a thickness of 100 nm, and is formed by vapor deposition on the PET film.

The support 54B is formed using a PET film with a thickness of 25 μm. The electrodes 53A and 53B are evaporated aluminum films with a thickness of 100 nm. The vibrator is a weight with a diameter of 9 mm. The thickness and materials of the dielectric layer, electrodes, spacer, and support can be set as appropriate.

The preferred thicknesses of the dielectric layer, the electrode, and the support are in the ranges of 0.01 μm to 500 μm, 0.01 μm to 1000 μm, and 1 μm to 1000 μm, respectively, and more preferably 0.05 μm to 200 μm, 0.02 μm to 500 μm, and 5 μm to 500 μm.
0 μm range.

The lower surface of the sensor body 41 (the surface of the support body 54B) is used as a contact surface 58 that comes into contact with the specimen 60. When the vibration responsive sensor 40 is in use, the entire contact surface 58 is brought into contact with the specimen 60 so as to be in close contact with the specimen 60. However, depending on the size of the specimen 60, the entire contact surface 58 may not be in close contact with the specimen 60. Meanwhile, the upper surface of the sensor body 41 (the surface of the support body 54A), which is the surface opposite the contact surface 58, is used as a pressing surface 59 that is pressed by the vibrator 42.

The vibrator 42 is a member that supplies vibrations to the sensor main body 41. For example, the vibrator 42 moves back and forth (reciprocating motion) with respect to a pressing surface 59, which is an example of a predetermined surface, by a drive mechanism, and repeats pressing the pressing surface 59 (supply of pressure and release of pressure supply) at a constant period (ω _I ). In this way, the vibrator 42 applies constant-period vibrations to the sensor main body 41. As described above, the vibrator 42 generates vibrations by supplying and releasing current to a solenoid, by collision between a rotating cam and a cam follower, by spraying high-pressure fluid, etc.

In the example shown in Figures 1 and 2, the upper surface (pressure surface 59) of the sensor body 41 is the vibration supply position. However, the position to supply the vibration may be a surface of the sensor body 41 other than the pressure surface 59, or may be an appropriate position on the specimen 60.

When the contact surface 58 of the sensor body 41 is in close contact with the specimen 60 and the vibrator 42 supplies vibrations at a constant cycle, the charged members 51A and 51B, which are stacked with a gap 44 between them, rub against each other. This causes charges to move from one of the charged members 51A and 51B to the other, generating a potential difference between the electrodes 53A and 53B. A lead wire 43A is connected to the electrode 53A, and a lead wire 43B is connected to the electrode 53B. These lead wires 43A and 43B are response signal extraction sections. Using the lead wires 43A and 43B, a signal indicating the variation in potential difference accompanying the supply of vibration (i.e., a response signal to the vibration) can be extracted, and the response signal waveform can be observed using a measuring device such as a current-voltage measuring device (electrometer) or an oscilloscope.

In the vibration responsive sensor 40, the period ( _ωI ) of the vibration supplied by the oscillator 42 resonates with the natural frequency ( _ωH ) of the specimen 60. This amplifies and distorts the natural frequency ( _ωH ) component (peak and phase) in the response signal extracted from the vibration responsive sensor 40. This means that information indicating the physical properties of the specimen 60, such as hardness and elasticity, and the contact state between the sensor body 41 and the specimen 60 (the shape of the specimen 60 and the position of an end face, if any) can be obtained from the waveform of the response signal.

Figure 3 shows the characteristics of the specimen 60, and the characteristics of the signal indicating pressure and the response signal. Four graphs are shown in Figure 3. The top row shows the response signal waveform when the specimen 60 is a hard material. The second row from the top shows the response signal waveform when the specimen 60 is a soft material. The third row from the top shows the response signal waveform when the specimen 60 is a low elasticity material. The bottom row shows the case where the width of the specimen 60 is shorter than the width of the contact surface 58.

The vertical axis of the graph showing the waveform indicates signal strength (level), and the horizontal axis indicates time. The pressure supply method used to obtain each signal is the same. The pressure is supplied so that it increases at a constant rate from a zero state to reach a peak, and after a while the peak is reached, it decays at a constant rate. For this reason, the pressure waveform has an isosceles trapezoidal shape. Note that in Figure 3, the response signal waveform is shown on top of the waveform showing the increase and decrease in pressure, but in a situation where there is no pressure supply, the potential difference is 0.

Assuming that the size of the specimen 60 is the same, if the specimen 60 is a hard material, the peak (increase) of the response signal will be small, and if the specimen 60 is a soft material, the peak of the response signal will be large. This is because it is considered that the harder the specimen 60 is, the lower the resonance width of the natural frequency ( _ωH ) of the specimen 60 with respect to the vibration frequency ( _ωI ), and therefore the smaller the change in the area (friction area) of the portion where the charged member 51A and the charged member 51B rub against each other. Conversely, it is considered that the softer the specimen 60 is, the higher the resonance width of the natural frequency ( _ωH ) with respect to the vibration frequency ( _ωI ), and therefore the larger the change in the friction area.

When the elasticity of the specimen 60 is low, the rate at which the response signal decays is slower than the rate at which the pressure decays, and a delay occurs in the part of the response signal that corresponds to the pressure decay. This is because a phase shift occurs in the natural frequency components of the response signal.

In addition, there may be a situation where the width of the specimen 60 is shorter than the width of the contact surface 58, and the contact surface 58 comes into contact with the edge of the specimen 60. For example, this is the case when the specimen is a resin tube. In this case, distortion occurs in the sensor body 41 when vibration is supplied, and an inverted portion appears in the response signal. For example, when pressure increases, the level of the response signal drops in the negative direction, and when pressure decays, the level of the response signal increases in the positive direction. The fact that such a signal is obtained can be used as position information.

As described above, the hardness of the specimen 60 can be determined by measuring the increase in the level (signal strength) of the response signal accompanying the supply of pressure. By determining in advance the correlation between the type of specimen 60 and the increase for multiple types of specimens 60, it is also possible to determine which of the multiple types of specimens an unknown specimen is.

The elasticity of the specimen 60 can be examined by measuring the delay time of the attenuation of the response signal relative to the attenuation of the pressure. By calculating in advance a value that indicates the correlation between the type of specimen 60 and the delay time for multiple types of specimens 60, it is also possible to determine which of the multiple types of specimens an unknown specimen is.

In addition, by checking for the presence or absence of an inversion of the signal, it is possible to check the contact state between the contact surface 58 and the specimen 60, or the shape of the specimen 60. When the vibration response sensor 40 is used in an environment where the types of specimens 60 are limited, if an inversion of the signal is observed (a decrease in the response signal in response to an increase in pressure, or vice versa), it can be determined that the type of specimen 60 is a specific substance or object.

The vibration response sensor 40 has a simple configuration in which two charged members 51A, 51B are stacked (opposed) with a spacer 55 in between, and outputs a response signal by generating electricity through friction, so no light-emitting element or power source is required to detect the response signal. With such a simple configuration, the physical properties and shape of the specimen 60 can be investigated, and numerical values (feature values) that indicate the correlation between the waveform characteristics and the physical properties and shape are obtained in advance by at least one of experiments and simulations and stored, and the physical properties and shape of the specimen 60 can be measured or the type of specimen 60 can be determined by comparing the characteristic values indicated by the response signal waveform of the specimen 60.

<Robot Hand>
Fig. 4 shows an example of a robot hand (gripping portion) 1 to which a vibration response sensor is applied. Fig. 5 shows a vibration response sensor 40 attached to the gripping portion 1. In Fig. 4, the gripping portion 1 includes a plurality of fingers 2, an actuator 3 connected to the fingers 2, and an arm 4 connected to the actuator 3. In the example shown in Fig. 4, two fingers 2 (2A and 2B) are illustrated. However, the number of fingers 2 may be two or more, and may be, for example, two to six. However, there is no upper limit.

In the example shown in FIG. 4, two fingers 2A and 2B pinch a specimen (object to be grasped) 60 from opposite directions, thereby making it possible to grasp the specimen 60. In this embodiment, the inside of each of the fingers 2A and 2B is formed of an elastic material. Also, the exterior of the finger 2 is soft. However, it is not essential to use an elastic material or a soft material. The finger 2 has a plurality of joints 1.
The actuator 3 drives the fingers 2A and 2B, causing the fingers 2A and 2B to grip the specimen 60. At this time, the specimen 60 is gripped so that the entire contact surface 58 is in close contact with the specimen 60.

The actuator 3 has a drive mechanism using a tension control thread 16. The spring 17 is given tension to push the fingers 2A and 2B from behind (in the direction of the arrow B1 in the figure), and the distance between the tips of the fingers 2A and 2B increases (the fingers 2A and 2B open in the direction B). When the tension control thread 16 is pulled in the direction of the arrow A1, and the traction force overcomes the biasing force of the spring 17 and the spring 17 contracts, the tips of the fingers 2A and 2B approach each other (the fingers 2A and 2B close in the direction of the arrow A in Figure 4), and the specimen 60 is grasped. The gripper 1 and the arm 4 can move vertically and horizontally (the XYZ directions of the three-axis coordinate system), and the inclination with respect to the vertical axis can be changed.

The vibration response sensor 40 has the same structure as that shown in Figures 1 and 2, and is attached to the inside of the upper finger portion 2A via support members 13, 13. The sensor body 41 of the vibration response sensor 40 is supported by the support members 13, 13 in a state separated from the vibrator 42 when vibration is not being supplied. The upper ends of the support members 13, 13 are connected to the finger portion 2A, and the lower ends are attached to the spacer 55.

When the fingers 2A and 2B grasp the specimen (object to be grasped) 60, the tension control thread 16 is pulled in the direction of arrow A1, and the fingers 2A and 2B close. At this time, the contact surface 58 of the vibration response sensor 40 is in close contact with the specimen 60. Furthermore, when the tension control thread 16 is pulled, the vibrator 15 performs a reciprocating motion in the up and down direction, pressing the pressure surface 59 at a constant cycle, and then the tension control thread 16 is loosened and the pressure on the vibrator 15 is released (pressure is supplied and released), and this is repeated to cause the vibrator 15 to vibrate.

The up-down reciprocating motion of the oscillator 15 is achieved, for example, by the following configuration. That is, the oscillator 42 serves as a cam follower, and a cam is disposed above the oscillator 42. The tension control thread 16 is wound around the rotation axis of the cam, and when the tension control thread 16 is pulled, the cam rotates. The cam abuts against the upper end (one end) of the oscillator 42 with each rotation, and this abutment causes the oscillator 42 to move downward. At this time, the lower end (other end) of the oscillator 42 presses against the pressing surface 59. When contact with the cam is released, the oscillator 42 moves upward due to the contraction of the spring. However, the mechanism for reciprocating the oscillator 42 is not limited to the above example.

Instead of the configuration shown in FIG. 2, a configuration may be adopted in which the vibrator 42 appears and disappears from the upper surface of the finger portion 2B due to vibration, and vibration is applied directly to the specimen 60 from below.

The pressure stimulus from the vibrator 42 causes the vibration response sensor 40 and the specimen 60 to resonate, and the potential difference caused by friction between the charged members 51A and 51B is taken out (detected) from the electrodes 53A and 53B by the lead wires 43A and 43B as a response signal to the vibration.

In the example shown in FIG. 5, lead wire 43A connected to electrode 53A and lead wire 43B connected to electrode 53B are arranged along support members 13A and 13B, pass through finger portion 2A and are drawn out from the upper surface of finger portion 2A. Lead wires 43A and 43B are connected to, for example, an electrometer, and the response signal waveform displayed on the display of the electrometer is observed.

The number of vibration response sensors 40 provided in the gripping portion 1 is not limited to one. When a plurality of vibration response sensors 40 are provided, it is possible to detect in more detail the change in vibration response when the finger portion 2 comes into contact with the specimen 60. The vibration response sensor 40 is preferably attached via support members 13, 13 to the position of the finger portion 2 where the finger portion 2 would first come into contact with the specimen 60 if the vibration response sensor 40 were not present.

When multiple types of graspable objects of different sizes are expected to be grasped, it is considered that the portion of the grasper 1 that grasps the specimen 60 is different for each specimen 60. For this reason, multiple vibration response sensors 40 may be provided on the finger portion 2. It is preferable that the portion of the finger portion 2 to which the vibration response sensors 40 are attached does not deform or only deforms to a small extent when the finger portion 2 is opened and closed.

The support 54B, which has a contact surface 58 with the specimen 60, acts as a protective layer to prevent damage to the dielectric layer 52B. To increase the sensitivity of the vibration response sensor 40, it is preferable that the support 54B is made of a material that is easily deformed and unlikely to cause friction. It is preferable that the electrodes 53A and 53B are made of a material that is easily deformed and unlikely to be damaged by deformation.

One of the dielectric layers 52A and 52B is made of a material that easily accumulates electric charge, and the other is made of a material that does not easily accumulate electric charge. The dielectric layers 52A and 52B may be made of materials with similar properties. When attaching the sensor body 41 to the finger portion 2 by adhering the spacer 55 and the support 54A to the finger portion 2, it is preferable that the support 54A is made of a material that is not easily damaged and has a high affinity with the adhesive. It is preferable that the electrodes 53A and 53B are made of a material that is easily deformed and is unlikely to be damaged by deformation.

When generating electricity by friction, the charged members 51A and 51B become charged members that are positively and negatively charged. In this case, it does not matter which of the electrodes 53A and 53B is positive or negative. For example, the electrode 53A may be positively charged and the electrode 53B may be negatively charged. Conversely, the electrode 53A may be negatively charged and the electrode 53B may be positively charged. The dimensions of the charged members 51A and 51B and the vibrator 42 are as described above, and the dimensions of the contact surface 58 are 18 mm x 18 mm.

(Waveform of vibration response sensor)
The advantage of using a vibration response sensor that uses an electrostatic sensor in the sensor body 41 is that it can detect much weaker forces than sensors that use the piezoelectric effect, and that the waveform obtained differs depending on the physical properties of the material that it comes into contact with and its ease of deformation.

Figure 6 shows an example of a pressure waveform and a response signal obtained by supplying pressure. In Figure 6, graph (A) shows the change over time in voltage indicating the pressure intensity supplied by the vibration response sensor 40. The pressure increases from 0 at a constant rate, maintains a peak value for a certain period of time, and decays to 0 at the same rate as the increase. The vibration response sensor 40 has the configuration described using Figures 1 and 2.

Graphs (B), (C), and (D) show the time-dependent change in voltage indicating the signal strength (level) of the response signal when the vibration response sensor 40 is brought into contact with a plurality of types of specimens and the pressure shown in graph (A) is applied. The specimen related to graph (B) is a soft polyethylene sponge (rubber hardness Asker C45 [Misumi Group Co., Ltd., antistatic polyethylene sponge (LBAPC10)], film thickness 10 mm, length 30 mm, width 40 mm). The specimen related to graph (C) is a hard silicone rubber (rubber hardness A50, Tigers Polymer Co., Ltd. "Hard Silicone Rubber Sheet"). The specimen related to graph (D) is a resilient hollow polyethylene tube (Hagitec Co., Ltd. VERSAFIT V2 7.0/3.50). The specimen related to graph (E) is a non-resilient 50 μm thick polyethylene bag (Asoh Co., Ltd.) inflated with air to a thickness of 70 mm, length 100 mm, and width 150 mm.

In the response signal waveform shown in graph (B), a response signal waveform similar to the oscillatory dynamic pressure waveform in graph (A) was obtained. In contrast, in graph (C), a response signal with weaker signal strength (lower level) was observed compared to graph (B).

In the stimulation vibration frequency (ω) region, the response of the vibration response sensor 40 (the product of the sensor's response function H (circumflex: Fourier series) (ω)) and the grasped object response (the grasped object response function G (circumflex: Fourier series) (ω))) to the stimulation vibration (I (circumflex: Fourier series) (ω)) is strong in the soft sponge. Therefore, a response signal (S (circumflex: Fourier series) (ω)) that approximates the pressure waveform (S (circumflex: Fourier series) (ω)) (S (circumflex: Fourier series) (ω) = I (circumflex: Fourier series) (ω) x sensor response function H (circumflex: Fourier series) (ω) x grasped object response function G (circumflex: Fourier series) (ω)) was obtained. In contrast, in the case of hard silicone rubber, the strength of H (circumflex: Fourier series) (ω) and G (circumflex: Fourier series) (ω) are low, and this is thought to be why the signal strength is low, as is the resonance strength. This makes it clear that a correlation can be obtained between the signal strength of the response signal of the vibration sensor 40 and the hardness of the object to be grasped.

Graph (D) shows a waveform that is similar overall to the pressure waveform in graph (A). However, immediately after pressure application begins, the signal level temporarily drops to the negative voltage side, then increases to the positive voltage side, resulting in a small negative peak. Also, immediately after pressure application begins to cease, a small positive peak occurs, where the voltage temporarily increases to the positive voltage side, then decreases to the negative voltage side.

The negative peak immediately after the start of pressure application is believed to have occurred for the following reason. That is, the diameter (7 mm) of the hollow polyethylene tube is smaller than the size of the contact surface 58 of the vibration response sensor 40. For this reason, pressure application causes the vibration response sensor 40 to deform in a bending manner, generating harmonic response components, which in turn delays the vibration response of the high-frequency components (phase shift of the peak), causing the phase to exceed 180 degrees, resulting in inversion. The occurrence of a small positive peak immediately after pressure application is stopped is also believed to have occurred for the same reason. This makes it clear that a correlation can be obtained between the inverted peaks occurring in the response signal and the shape of the object to be grasped.

Graph (E) shows a trapezoidal shape that is similar to the pressure waveform in graph (A), and good resonance between the vibration response sensor 40 and the specimen 60 is evident. However, a change from the pressure waveform was observed in the decay waveform after the supply of pressure (pressurization) was stopped. That is, in the case of a polyethylene bag with no elasticity (resilience), a delay in the decay time (slower decay than the pressure decay) was observed. This result shows that the lower the elasticity of the specimen, the longer the time required for the response waveform to decay, and it became clear that a correlation can be obtained between the delay time and the elasticity of the specimen.

By utilizing the above, it is possible to determine the hardness and shape of the object to be grasped that comes into contact with the vibration response sensor, or the presence or absence of an edge. In addition, by controlling the drive speed of the transducer 42 to change the frequency of the repeated stimulation vibration of applying pressure and releasing pressure on the transducer, more detailed data can be obtained, and multiple waveforms can be obtained, allowing the hardness of the specimen 60 to be determined in more detail. In addition, the gripping unit 1 does not require a large number of wirings due to the installation of multiple sensors as in the conventional technology, and there is no need to improve strength to take into account the large number of wirings.

<Determination device>
FIG. 7 is a block diagram showing an example of the configuration of a determination device for a sample according to an embodiment.
The computer 200 includes a processor 201 , a storage device 202 , a communication interface (communication IF) 203 , an input device 204 , and a display 205 , which are interconnected via a bus 210 .

The bus 210 is connected to a motor 206, which is connected to a manipulator 207 including a gripper 1. A vibration response sensor 40 is attached to the gripper 1, and the vibration response sensor 40 is connected to an electrometer 208 via leads 43A and 43B.

A general-purpose or dedicated computer can be applied as the determination device 200. The storage device 202 includes a main storage device and an auxiliary storage device. The main storage device is used as a storage area for programs and data, a working area for the processor 201, and a buffer area for communication data. The auxiliary storage device is used as a storage area for programs and data. The main storage device is a RAM (Random Access Memory) or a combination of a RAM and a ROM (Read Only Memory). The auxiliary storage device is a hard disk, an SSD (Solid State Drive), an EEPROM, or the like.
M, etc.

The communication IF 203 is an interface that communicates (input/output) information with a server or other devices via a wired or wireless network. The communication IF 203 is, for example, a network interface card or a wireless communication module (circuit chip). The input device 204 is a key, button, pointing device, touch panel, etc., and is used to input data and information to the determination device. The display 205 is used to display data and information.

The processor 201 is, for example, a CPU (Central Processing Unit), and
The processor 201 operates as a control device that controls the operation of the robot hand (the gripping unit 1) by executing a program stored in the processor 202. The processor 201 performs various processes according to commands received from an external device via a communication IF 203, commands input by an operator of the gripping unit 1 using an input device 204, or commands generated by executing a program.

For example, the processor 201 calculates the control amount (amount of rotation) of the motor 206 that controls the position and inclination of the gripping part 1, the opening and closing of the finger part 2, etc., and supplies a control signal indicating the control amount to the motor 206. The motor 206 includes multiple stepping motors corresponding to the multiple joints of the manipulator 207, and rotates in the forward or reverse direction by an amount according to the control amount provided by the processor 201. This controls the position and inclination of the gripping part 1, the opening and closing of the finger part 2, etc.

One of the motors 206 rotates forward or backward to wind or unwind the tension control thread 16 in accordance with a control signal (a command to rotate forward or rotate by a controlled amount) given by the processor 201. Unwinding the tension control thread 16 opens the fingers 2A and 2B, and winding it closes the fingers 2A and 2B.

A vibration response sensor 40 is attached to the gripping part 1, and the vibration response sensor 40 is connected to the electrometer 208 via lead wires 43A and 43B. When the gripping part 1 grips the specimen 60 and the contact surface 58 is in close contact with the specimen 60, the vibrator is vibrated by controlling the motor 206, and a potential difference is generated in the vibration response sensor 40 due to frictional power generation. A response signal indicating the current or the change in current over time caused by this potential difference is input to the electrometer 208 via the lead wires 43A and 43B.

The electrometer 208 measures the response signal (a change over time in the response signal (current or voltage) accompanying repeated supply and release of pressure), and displays a current or voltage waveform indicating the response signal, such as that shown in Figures 3 and 6, on a display provided in the electrometer 208. By observing the waveform, the hardness, elasticity, shape, etc. of the specimen 60 can be visually determined.

(Processing example 1)
The response signal output from the vibration response sensor 40 is amplified by an amplifier included in the determination device 200, converted into a digital signal by an AD converter, and then input to the processor 201 via the bus 210. The digital signal input to the processor 201 indicates the vibration caused by the vibrator 42, i.e., the output signal (change over time (waveform) of current or voltage) from the vibration response sensor 40 accompanying the supply and release of pressure. Since the voltage waveform changes more greatly than the current waveform, it is preferable to use the voltage waveform.

The processor 201 compares data relating to various waveforms pre-stored in the memory device 202 with the waveform acquired from the vibration response sensor 40 to calculate (determine) the hardness of the specimen 60 grasped by the gripping unit 1. The memory device 202 stores data relating to waveforms corresponding to the hardness of the specimen 60 as information for determination. Therefore, the processor 201 can calculate (determine) the hardness of the specimen 60 grasped by the gripping unit 1 by comparing the data relating to the waveforms stored in the memory device 202 with the waveforms acquired from the vibration response sensor 40 (referred to as "measured values").

Figure 8 is a table showing an example of information for determination. The table consists of one or more entries (records) including information indicating hardness, threshold, and specimen type. Hardness may be some kind of physical quantity or a value indicating relative hardness in comparison with a certain object. For example, it may be a relative value indicating hardness between multiple types of specimens. In the example table shown in Figure 8, the relationship between the hardness of specimens A, B, and C, which have different hardness, and the determination threshold is recorded for each record. Hardness "1" is the softest, and the harder the value, the harder the specimen. The threshold is TH1<TH2<TH3.

Figure 9 is a flowchart showing an example of the process of determining hardness and specimen type by the processor 201. In step S01, the processor 201 acquires a measurement value of the response signal output from the vibration response sensor 40 when a certain specimen 60 is grasped and vibration is applied. The measurement value is, for example, a value indicating the amount of rise (increase) in the voltage level due to the application of pressure, but may be something else.

In step S02, the processor 201 determines whether the measurement value falls within a predetermined threshold range. The threshold range in step S02 is "0<measurement value=<threshold value TH1". If it is determined that the measurement value falls within the threshold range (YES in S02), the processor 201 determines that the hardness of the specimen 60 is "1" and that the specimen 60 is specimen "A". If it is determined in step S02 that the measurement value does not fall within the threshold range (NO in S02), the process proceeds to step S03.

In step S03, the processor 201 determines whether the measurement value falls within a predetermined threshold range. The threshold range in step S03 is "TH1 < measurement value = < threshold value TH2". If it is determined that the measurement value falls within the threshold range (YES in S03), the processor 201 determines that the hardness of the specimen 60 is "2" and that the specimen 60 is specimen "B". If it is determined that the measurement value does not fall within the threshold range (NO in S03), the processor 201 determines that the hardness of the specimen 60 is "3" and that the specimen 60 is specimen "C".

Furthermore, the processor 201 controls the gripping state of the gripping unit 1 according to the hardness of the specimen 60 gripped by the gripping unit 1. The processor 201 controls the gripping state of the gripping unit 1 by controlling a vibration response of the gripping unit 1 in the gripping state of the specimen 60. For example, the processor 201 may control the vibration response applied to the specimen 60 when the gripping unit 1 grips the specimen 60 by controlling the drive amount of the finger unit 2.

For example, a waveform corresponding to the hardness of the specimen 60 and control information corresponding to the hardness of the specimen 60 may be associated and stored in the storage device 202. The control information is information for controlling the gripping state of the gripping unit 1, for example, information regarding the drive amount of the finger unit 2. The processor 201 may refer to the storage device 202 based on the waveform acquired from the vibration response sensor 40, acquire control information from the storage device 202, and control the gripping state of the gripping unit 1. Specifically, when the object is determined to be soft, the amount of winding can be increased compared to when the object is determined to be hard, so that the object can be held securely. This increased amount of winding can be appropriately increased, taking into account not only the softness of the object but also its susceptibility to breakage. Furthermore, the processor 201 may control the movement (position) and inclination of the gripping unit 1 based on the waveform acquired from the specimen 60 or the vibration response sensor 40.

The gripping state of the gripping portion 1 (the amount of winding of the tension control thread 16) based on the hardness of the specimen 60 can be controlled, for example, as follows.
[1] Example of threshold setting using correlation between signal intensity and stiffness, and method for classifying specimen stiffness The stiffness of a specimen correlates with the intensity of a response signal. For example, if the specimen is soft, the signal intensity is large (see graph (B) in FIG. 6 ), and if the specimen is hard, the signal intensity is small (see graph (C) in FIG. 6 ).

Taking the above into consideration, for example, by making the following settings, the processor 201 can classify the hardness of the specimens A, B, and C (A (soft) < B < C (hard)) using the table shown in FIG. 8 and the algorithm in FIG. 9.
The signal intensity in graph (B) divided by the signal intensity in graph (B) is set as the first threshold (TH1).
The signal intensity in graph (B) divided by the signal intensity in graph (C) is set as the second threshold (TH2).
The third threshold (TH3) is set to twice the second threshold (TH).

[2] Control of the winding amount of the thread (wire) After classifying the specimen (assessing whether the specimen is A, B, or C) by vibration response sensing, the tension control thread 16 (wire) is wound to grip the specimen. In this case, if the specimen is evaluated as A (soft specimen), in order to avoid damage to the specimen, the limit value (maximum value) of the winding amount of the tension control thread 16 is made smaller than the reference value, and the winding amount is controlled so that the specimen is gripped with a weak force. Conversely, if the specimen is evaluated as C (hard specimen), the limit value of the winding amount is made larger than the reference value, and the winding amount is controlled so that the specimen is gripped with a strong force. Note that the limit value of the winding amount when the specimen is B may be set to the reference value, and the reference value may be determined regardless of whether the specimen is B or not.

In addition to the configuration using the tension control thread 16, the finger portion 2 may be driven by a drive mechanism using the deformation tension of the dielectric elastomer, thread tension, air pressure, or hydraulic pressure (e.g., hydraulic pressure). The drive mechanism using the deformation tension of the dielectric elastomer, thread tension, air pressure, or hydraulic pressure can control the vibration response of the gripping portion 1 gripping the specimen 60 without using complex mechanisms such as gears. In addition, the drive mechanism using the deformation tension of the air dielectric elastomer, thread tension, air pressure, or hydraulic pressure does not generate a magnetic field, so it can control the gripping portion 1 without affecting other equipment.

For example, the processor 201 can determine whether the specimen 60 gripped by the gripping unit 1 is a pass or fail product based on the waveform acquired from the vibration response sensor 40.
In the memory 02, data on the waveform according to the hardness of the specimen 60 is stored in association with data indicating whether the specimen 60 is good or bad. This waveform data can also be recorded as two-dimensional data by plotting the signal intensity at the peak obtained by Fourier transforming the real-time waveform of the vibration response sensor 40 against the x and y axes, with the magnitude (∝ 1/(spatial frequency (k))) and the vibration frequency (ω) of the stimulating vibration surface (pressure surface of the transducer 42) of the stimulating vibration unit on the x and y axes, and the phase of the peak.

The processor 201 may compare data regarding a waveform corresponding to the hardness and shape of the specimen 60 with a waveform acquired from the vibration response sensor 40 to determine whether the specimen 60 grasped by the grasping unit 1 is a good or bad product.

As described above, the hardness of the specimen can be determined from the strength of the response signal. For example, if the specimen is an apple, it will be hard (good) if it is fresh, and will become soft (defective) if its freshness decreases (rot). Therefore, by adopting the following configuration, it is possible to determine whether the specimen (apple) is good or bad.
Using a vibration response sensor, measure the strength of the response signal when checking the hardness of a defective product (large strength, referred to as signal strength B') and the strength of the response signal when checking the hardness of a good product (small strength, referred to as signal strength C').
The value obtained by dividing the signal strength C' by the signal strength B' is set as the threshold value (TH1) for determining whether the sample is good or bad, and the processor 201 performs the processes S01 and S02 in FIG. 9 on the sample.
In the process of S02, if the measured value (signal intensity) is greater than 0 and less than the threshold value TH1, the sample is classified into the non-defective class (determined to be a non-defective product). If not, the sample is classified into the defective class (determined to be a defective product).

As a result, for example, when the specimen 60 is fruit, the processor 201 can sort the fruit. Also, for example, poor quality fruits can be sorted for juice and good quality fruits can be sorted for eating raw. Furthermore, the processor 201 may determine the damage state of a particular fruit based on the waveform acquired from the vibration response sensor 40 in combination with AI (Artificial Intelligence) or deep learning.

In addition, each of the multiple finger portions 2 may be replaceable, or the finger portions 2 and the actuators 3 may be replaceable. In the case of a drive mechanism using the deformation tension of a dielectric elastomer, thread tension, or air pressure, it is easy to replace the finger portions 2 and the actuators 3. The gripping portion 1 may be attached to the arm portion 4 in a replaceable manner. In addition, by providing an imaging device such as a camera to the manipulator 207, the imaging device may capture an image of the specimen 60, and the processor 201 may identify the type of specimen 60.

As described above, the processor 201 controls the gripping state of the gripping unit 1 based on a signal corresponding to the vibration response applied to the vibration response sensor 40. This allows the specimen 60 to be gripped appropriately. For example, the processor 201 can control the gripping state of the gripping unit 1 according to the hardness of the specimen 60, thereby allowing the specimen 60 to be gripped appropriately.

(Processing example 2)
The response signal of the vibration response sensor 40, i.e., information (measured value) indicating a temporal change in current or voltage accompanying the supply and release of pressure, is input to the determination device 200 and stored in the memory device 202. The memory device 202 stores determination information related to multiple types of specimens treated as specimens 60 of the gripping portion 1. The determination information may be obtained by reading out determination information previously stored in the memory device, or may be read out from an external memory device connected to the determination device 200, or may be obtained by timely communication.

The information for judgment is the amount of change in level (magnitude of level fluctuation) associated with the supply and release of pressure.
By comparing the measured value of the change with the threshold, samples that are greater than the threshold and samples that are less than the threshold can be determined to be different types.

The determination information may also include one or more thresholds for the decay time of the response signal (the time from when the pressure supply is released (stopped) until the value of the response signal becomes 0). The type of sample can be determined by comparing such thresholds with the measured decay time.

The type of sample can also be determined based on whether or not the response signal (determining value) shows at least one of an increase in level during the pressure increase period and a decrease in level during the pressure decay period.

In this way, the determination device 200 can identify the specimen using the measurement value of the response signal related to the specimen and the determination information. It can also measure the relative physical properties (hardness and elasticity) of the specimen relative to the comparison object. That is, it can measure the relative physical properties of the grasped specimen by comparing different objects, or comparing objects of the same type but with different shapes. It can also indicate the hardness and elasticity (recovery force) of the specimen in some units, even if there is no comparison object. Furthermore, it can determine the shape and contact state of the grasped specimen by determining the presence or absence of a phase inversion point in the signal.

Figure 10 is a flow chart showing an example of a sample determination process by the processor 201. The process in Figure 10 is a process for identifying samples a to e of different types (physical properties and shapes). In step S101, the processor 201 acquires a measurement value of a response signal related to the sample. The measurement value may be supplied in real time from the electrometer 208 or may be read out at a predetermined timing from the storage device 202.

In step S102, the processor 201 analyzes the waveform to determine whether or not there is a phase inversion in the response signal period corresponding to the pressure increase period or the pressure decay period, for the response signal (voltage change) corresponding to one pressure supply and its release. If it is determined that there is a phase inversion (YES in S102), it is determined that the specimen to be identified is specimen c. On the other hand, if it is determined that there is no phase inversion (NO in S102), the process proceeds to step S103.

In step S103, the processor 201 analyzes the waveform to determine whether the decay time of the response signal (voltage change) corresponding to one pressure supply and release, which corresponds to the pressure decay period, is longer than a threshold value. If the decay time is longer than the threshold value (there is a delay time), the process proceeds to step S104, and if it is determined that the decay time is not longer than the threshold value, the process proceeds to step S105.

In step S104, the processor 201 determines whether the length of the delay time is equal to or greater than a threshold. If it is determined that the length of the delay time is equal to or greater than the threshold (YES in S104), the sample is determined to be sample e, and if not (NO in S104), the sample is determined to be sample d.

In step S105, the processor 201 analyzes the waveform to determine whether the level (increase) of the response signal (voltage change) corresponding to one pressure supply and its release is greater than a threshold value. If the level is determined to be greater than the threshold value (YES in S105), the specimen 60 is determined to be specimen b. In contrast, if the level is equal to or less than the threshold value (NO in S105), the specimen is determined to be specimen a. In this way, it can be determined that the specimen 60 that has come into contact with the vibration response sensor 40 is one of specimens a to e.

The processor 201 is an example of a "determination circuit," and the processing performed by the processor 201 as a determination circuit may be performed by a processor other than a CPU, such as multiple CPUs, a CPU having multiple cores, a DSP, or a GPU. The processing as a determination circuit may also be performed by an integrated circuit such as an ASIC or an FPGA, or a combination of a processor and an integrated circuit (such as a System-on-a-Chip (SoC)). The configurations described in the above embodiments can be combined as appropriate without departing from the scope of the invention.

1: gripping portion 40: vibration response sensor 41: sensor body 42: vibrator 43: removal portion 44: gaps 51A, 51B: charged member (charged body)
52A, 52B... Dielectric layers 53A, 53B... Electrode 58... Contact surface 59... Pressing surface 60... Sample 200... Determination circuit 201... Processor 202... Storage device

Claims (5)

a sensor body which is a frictional electrification sensor having a contact surface to be brought into contact with a specimen;
a vibrator that supplies vibration to the specimen or the sensor body in a contact state in which the contact surface is in contact with the specimen;
an extraction unit that extracts a response signal indicating a response to the supply of the vibration from an electrode included in the sensor body;
Including,
The sensor body has a structure in which two charged members, each including the electrode and a dielectric layer, are stacked with a gap therebetween.
Vibration response sensor. The dielectric layer is formed of a resin film.
2. The vibration response sensor of claim 1 . The vibrator supplies vibration to a surface of the sensor body opposite to the contact surface.
3. The vibration response sensor according to claim 1 or 2 . The oscillator applies pressure to the specimen or a predetermined surface of the sensor body and releases the pressure by moving back and forth.
A vibration response sensor according to any one of claims 1 to 3 . A gripping portion;
The vibration response sensor according to claim 1 , which is attached to the grip portion; and
A robotic hand including

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