WO2024089940A1 - Détecteur de charge et organe de préhension - Google Patents

Détecteur de charge et organe de préhension Download PDF

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Publication number
WO2024089940A1
WO2024089940A1 PCT/JP2023/024092 JP2023024092W WO2024089940A1 WO 2024089940 A1 WO2024089940 A1 WO 2024089940A1 JP 2023024092 W JP2023024092 W JP 2023024092W WO 2024089940 A1 WO2024089940 A1 WO 2024089940A1
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WO
WIPO (PCT)
Prior art keywords
load
load detector
article
claws
load sensor
Prior art date
Application number
PCT/JP2023/024092
Other languages
English (en)
Japanese (ja)
Inventor
博伸 浮津
玄 松本
洋大 松村
進 浦上
敬史 濱野
祐太 森浦
Original Assignee
パナソニックＩｐマネジメント株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Publication of WO2024089940A1 publication Critical patent/WO2024089940A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J15/00—Gripping heads and other end effectors
    • B25J15/08—Gripping heads and other end effectors having finger members
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/14—Measuring force or stress, in general by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
    • G01L5/22—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers

Definitions

  • the present invention relates to a load detector for detecting an applied load, and a robot hand equipped with the load detector.
  • robot hands that can grasp objects are used in a variety of fields.
  • a hand for grasping objects is placed at the end of a multi-joint arm.
  • the hand is equipped with multiple claws that can be opened and closed. This allows a specific object to be grasped with the multiple claws and transported from one location to another.
  • Such robotic hands need to grasp objects in a way that prevents them from slipping off under their own weight.
  • the objects to be grasped differ depending on the type of object, in terms of slipperiness, weight, fragility, shape, etc. For this reason, the robotic hand needs to grasp the object with the appropriate strength depending on the object's characteristics, so that the object does not slip off.
  • Patent Document 1 describes a robot hand that can detect when a grasped object slips due to its own weight.
  • multiple sensors are placed on the palm surface of the robot hand. Slippage between the fingertips of the robot hand and the object is detected from the distribution of pressure detection values from these sensors.
  • the present invention aims to provide a load detector capable of detecting slippage of a grasped object with a simple configuration and simple processing, and a robot hand equipped with the load detector.
  • the first aspect of the present invention relates to a load detector.
  • the load detector according to this aspect includes a moving body having a predetermined thickness, a support having a recess that accommodates the moving body so that the moving body can move in a direction perpendicular to the thickness direction, a load sensor interposed between the outer surface of the moving body and the inner surface of the recess, and an anti-slip member disposed on the surface of the moving body opposite the bottom surface of the recess.
  • the second aspect of the present invention relates to a robot hand.
  • the robot hand according to this aspect includes a plurality of claws for gripping an object, a load detector according to the first aspect arranged on at least one of the claws so that the anti-slip member comes into contact with the object when the object is gripped, and a control unit that determines whether the object is slipping relative to the claws based on whether the load obtained from the load sensor varies in accordance with the fixation and slippage of the object when the object is gripped and lifted by the plurality of claws.
  • the load detector and robot hand when an object is grasped and lifted by the multiple claws, the presence or absence of slippage of the object relative to the claws is determined based on whether or not the load obtained from the load sensor fluctuates due to the fixation and slippage of the object, i.e., the stick-slip phenomenon.
  • This makes it possible to reduce the number of load sensors arranged in the load detector for slippage detection, and to simplify the configuration. Furthermore, since it is only necessary to determine whether or not a fluctuation occurs in the load due to the stick-slip phenomenon, slippage of the object can be detected by simple processing.
  • the present invention provides a load detector capable of detecting slippage of a grasped object through a simple configuration and simple processing, and a robot hand equipped with the load detector.
  • FIG. 1 is a side view illustrating a schematic configuration of a robot hand according to an embodiment.
  • FIG. 2 is an enlarged side view showing a state in which an article is gripped by a pair of claws according to the embodiment.
  • FIG. 3 is a cross-sectional view of the load detector of FIG. 2 according to an embodiment.
  • Fig. 4(a) is a plan view showing the configuration of a load detector according to an embodiment
  • Fig. 4(b) is a plan view showing the configuration of a load detector according to an embodiment with the anti-slip member, the restricting member, and the dustproof member removed from the configuration of Fig. 4(a).
  • Fig. 4(a) is a plan view showing the configuration of a load detector according to an embodiment with the anti-slip member, the restricting member, and the dustproof member removed from the configuration of Fig. 4(a).
  • Fig. 4(a) is a plan view showing the configuration of a load detector according to an embodiment with the anti-slip
  • FIG. 5(a) is a perspective view showing a base member and a conductive elastic body provided on an upper surface of the base member according to an embodiment
  • Fig. 5(b) is a perspective view showing a state in which a conductor wire is provided on the structure of Fig. 5(a) according to an embodiment
  • Fig. 6(a) is a perspective view showing a state where a thread is provided on the structure of Fig. 5(b) according to the embodiment
  • Fig. 6(b) is a perspective view showing a state where a base member is provided on the structure of Fig. 6(a) according to the embodiment
  • FIG. 7 is a plan view illustrating a schematic internal configuration of the second load sensor according to the embodiment.
  • FIG. 8(a) is a perspective view showing a base member, a conductive elastic body and a conductor wire disposed on an upper surface of the base member according to an embodiment
  • Fig. 8(b) is a perspective view showing a state in which the base member is disposed on the structure of Fig. 8(a) according to an embodiment
  • FIG. 9 is a block diagram showing the configuration of a circuit section of a robot hand according to an embodiment.
  • FIG. 10 is a graph illustrating a load obtained by the first load detection unit when a gripped article slips on the pair of claws according to the embodiment.
  • 11A and 11B are diagrams illustrating a method for detecting the weight of an article according to an embodiment.
  • FIG. 12 is a flowchart illustrating control of a robot hand during a gripping operation according to an embodiment.
  • FIG. 13 is an enlarged side view showing a configuration in the vicinity of a pair of claws according to the first modified example.
  • FIG. 14 is an enlarged side view showing a configuration in the vicinity of a pair of claws according to the second modified example.
  • Fig. 15(a) is a diagram showing a configuration of a structure for constituting the first load sensor and the second load sensor according to Modification Example 3.
  • Fig. 15(b) is a diagram showing another configuration of a structure for constituting the first load sensor and the second load sensor according to Modification Example 3.
  • FIG. 16 is a perspective view showing a configuration of a load detector according to the third modified example.
  • 17(a) and (b) are plan views showing the configuration of a load detector according to the fourth modified example.
  • 18(a) and (b) are plan views showing the configuration of a load detector according to the fifth modified example.
  • each drawing is indicated with mutually orthogonal X, Y and Z axes.
  • the Z-axis direction is the height direction of the robot hand.
  • FIG. 1 is a side view that shows a schematic diagram of the configuration of the robot hand 1.
  • the robot hand 1 comprises an arm 2 and a hand 3.
  • the arm 2 comprises multiple arm sections 2a to 2d and drive sections 2e to 2h that rotate the arm sections 2a to 2d in a predetermined direction.
  • the arm section 2a is shown positioned parallel to the Y axis.
  • Arm portion 2a is supported by arm portion 2b so as to be rotatable about a rotation axis parallel to the Y axis, and is rotated about said rotation axis by drive portion 2e.
  • Arm portion 2b is supported by arm portion 2c so as to be rotatable about a rotation axis parallel to the X axis, and is rotated about said rotation axis by drive portion 2f.
  • Arm portion 2c is supported by arm portion 2d so as to be rotatable about a rotation axis parallel to the X axis, and is rotated about said rotation axis by drive portion 2g.
  • Arm portion 2d is supported by drive portion 2h so as to be rotatable about a rotation axis parallel to the Z axis, and is rotated about said rotation axis by drive portion 2h.
  • Drive portion 2h is fixed on the ground G0.
  • the hand 3 is supported at the tip of the arm portion 2a so as to be rotatable about a rotation axis parallel to the X-axis.
  • the hand 3 is rotated about this rotation axis by the drive portion 2i.
  • the hand 3 has a pair of claws 3a that protrude downward.
  • the pair of claws 3a are aligned parallel to each other in the Y-axis direction, and each is driven individually in the Y-axis direction.
  • a load detector 4 is installed on each of the opposing surfaces of the pair of claws 3a.
  • the hand 3 grasps an object 5 through the two load detectors 4 by bringing the pair of claws 3a close to each other.
  • the robot hand 1 drives the arms 2a-2d and the hand 3 to place the grasped item 5 on the top surface of the workpiece 6.
  • the workpiece 6 is placed on the top surface of the stage 7.
  • the stage 7 is supported by a support base 8 that is placed on the ground G0.
  • FIG. 2 is an enlarged side view showing an article 5 being gripped by a pair of claws 3a.
  • FIG. 3 is a cross-sectional view of the load detector 4 in FIG. 2, cut at the midpoint of the X-axis along a plane parallel to the Y-Z plane. For convenience, only the load detector 4 is shown in cross-section in FIG. 3.
  • an acceleration sensor 9 capable of detecting acceleration in three-dimensional directions is installed on the upper surface of the load detector 4.
  • Each load detector 4 includes a first load sensor 10, a second load sensor 20, a moving body 30, a support body 40, an anti-slip member 50, a regulating member 60, and a dustproof member 70.
  • the moving body 30 is a member having a predetermined thickness, and is housed in a recess 41 of the support 40 so as to be movable in a direction perpendicular to the thickness direction.
  • a first load sensor 10 is interposed between the outer surface of the moving body 30 and the inner surface of the recess 41.
  • An anti-slip member 50 is disposed on the surface of the moving body 30 on the opposite side to the bottom surface of the recess 41.
  • the anti-slip member 50 is disposed on the surface of the moving body 30 via the second load sensor 20.
  • FIG. 4(a) is a plan view of the load detector 4 on the negative side of the Y axis in FIG. 3, as viewed from the positive side of the Y axis.
  • FIG. 4(b) is a plan view showing the configuration in FIG. 4(a) with the anti-slip member 50, regulating member 60, and dustproof member 70 removed.
  • each part in FIGS. 4(a) and (b) is hatched in the same way as in FIG. 3.
  • the moving body 30 has a rectangular shape in a plan view.
  • the thickness of the moving body 30 is constant.
  • the moving body 30 is made of a hard material that is not easily deformed so that it does not expand in a direction parallel to the Y-Z plane due to the load when the object 5 is sandwiched between the pair of load detectors 4.
  • the moving body 30 is made of a highly rigid material such as acrylic. It is preferable that the specific gravity (weight) of the moving body 30 is small.
  • the movable body 30 is made of a material with high self-lubricating properties so that the weight of the article 5 causes the movable body 30 to slide easily against the support 40 when the article 5 is sandwiched between the pair of load detectors 4. Furthermore, a configuration for enhancing lubricity may be applied to the surface of the movable body 30 (the surface on the negative side of the Y axis) that contacts the bottom surface of the recess 41. For example, a lubricant or the like may be applied to this surface.
  • a plurality of hemispherical protrusions or semicylindrical ridges may be formed on this surface to reduce the contact area with the bottom surface of the recess 41 and enhance the lubricity with respect to the bottom surface of the recess 41.
  • Such protrusions or ridges may be formed on the bottom surface of the recess 41, rather than on the surface of the movable body 30.
  • the first load sensor 10 detects a load corresponding to the weight of the item 5 when the item 5 is pinched between a pair of claws 3a via a pair of load detectors 4 as shown in FIG. 3.
  • multiple first load sensors 10 are arranged in the gap between the inner surface of the recess 41 and the outer surface of the moving body 30. These first load sensors 10 are attached to the outer surface of the moving body 30 with an adhesive or the like. These first load sensors 10 may also be attached to the inner surface of the recess 41.
  • a pair of first load sensors 10 are arranged at positions sandwiching the moving body 30, and another pair of first load sensors 10 are arranged at other positions sandwiching the moving body 30 in a direction intersecting a line connecting the pair of first load sensors 10. That is, in a planar view, a first load sensor 10 is arranged on each of the four sides of the moving body 30.
  • the width of the first load sensor 10 in the Y-axis direction is slightly smaller than the thickness of the moving body 30.
  • the first load sensors 10 are installed on the corresponding side surfaces of the moving body 30 so as to fall within the range of the thickness of the moving body 30.
  • the moving body 30 on which the four first load sensors 10 are installed is housed in the recess 41 with almost no play in the direction parallel to the X-Z plane.
  • the moving body 30 can move by a stroke equal to the sum of this play and the amount of elastic deformation of the first load sensor 10 due to a load in a direction parallel to the X-Z plane. In this way, by minimizing play, the first load sensor 10 can detect the load that occurs as the moving body 30 moves with high response.
  • the second load sensor 20 is installed on the surface of the moving body 30 opposite the bottom surface of the recess 41.
  • the shape of the second load sensor 20 in a plan view is a rectangle smaller than the moving body 30.
  • the second load sensor 20 is disposed in the center of the surface of the moving body 30. As described below, the second load sensor 20 has multiple detection areas.
  • the second load sensor 20 may be configured to have only one detection area.
  • the support 40 is made of a hard material that is difficult to deform.
  • the support 40 is made of a metal material such as SUS or aluminum.
  • a recess 41 of a certain depth is formed in the support 40.
  • the depth of the recess 41 is approximately the same as the thickness of the moving body 30.
  • the support 40 has a rectangular shape, and the recess 41 also has a rectangular shape.
  • the size of the recess 41 in a plan view is slightly larger than the size of the structure consisting of the moving body 30 and the four first load sensors 10.
  • the bottom surface of the recess 41 may also be configured to increase lubricity so that the moving body 30 can slide easily. For example, a lubricant or the like may be applied to the bottom surface of the recess 41.
  • the anti-slip member 50 is intended to prevent the article 5 from slipping off due to its own weight when the article 5 is sandwiched between a pair of load detectors 4 as shown in FIG. 3.
  • the anti-slip member 50 is made of a highly tacky (sticky) material such as rubber. As described above, the lubricity between the moving body 30 and the bottom surface of the recess 41 is enhanced. Therefore, by bringing the highly tacky anti-slip member 50 into contact with the article 5, the load corresponding to the weight of the article 5 is easily transmitted to the first load sensor 10. This allows the weight and slippage of the article 5 to be properly detected from the load detected by the first load sensor 10. The method of detecting the weight and slippage of the article 5 will be described later with reference to FIG. 10 and FIGS. 11(a) and (b).
  • the restricting member 60 restricts the moving body 30 from slipping out of the recess 41.
  • the restricting member 60 is installed on the support 40 so as to face the outer periphery of the surface of the moving body 30.
  • the restricting member 60 is a thin plate and frame-shaped member with an opening in the center.
  • the outer shape of the restricting member 60 in a plan view is the same as the outer shape of the support.
  • the shape of the opening of the restricting member 60 in a plan view is a rectangle that is slightly smaller than the shape of the moving body 30.
  • the restricting member 60 is made of, for example, a metal material. It is preferable that the surface of the restricting member 60 facing the moving body 30 is formed to have high lubricity.
  • the restricting member 60 is fixed to the support 40 by an adhesive or the like.
  • the dustproof member 70 prevents dust from entering between the moving body 30 and the recess 41.
  • the dustproof member 70 covers the gap between the moving body 30 and the recess 41.
  • the dustproof member 70 is a thin plate and frame-shaped member with an opening in the center. The opening of the dustproof member 70 is smaller than the opening of the regulating member 60 and slightly larger than the size of the second load sensor 20.
  • the dustproof member 70 is made of, for example, a metal material, and is fixed to the upper surface of the regulating member 60 by an adhesive or the like.
  • the regulating member 60 and the dustproof member 70 may be fixed to the support body 4 by screws.
  • the dustproof member 70 may be omitted. In this case, the opening of the restricting member 60 may be reduced to provide the same dustproof effect as the dustproof member 70. When the dustproof member 70 is omitted, the restricting member 60 is also used as the dustproof member.
  • the first load sensor 10 and the second load sensor 20 are configured as capacitance-type load sensors.
  • the first load sensor 10 and the second load sensor 20 each include a conductive elastic body, a linear conductive member, and a dielectric interposed between the conductive elastic body and the conductive member.
  • the first load sensor 10 and the second load sensor 20 are not limited to the configuration shown below, and may be capacitance-type load sensors of other configurations.
  • the first load sensor 10 and the second load sensor 20 may be resistive film type or piezoelectric element type load sensors.
  • FIG. 5(a) is a perspective view that shows a schematic diagram of a base member 21 and a conductive elastic body 22 that is placed on the upper surface (the surface on the positive side of the Z axis) of the base member 21.
  • the base member 21 is an elastic, insulating, flat-plate member.
  • the base member 21 has a rectangular shape in a plan view.
  • the thickness of the base member 21 is constant.
  • the thickness of the base member 21 is, for example, 0.01 mm to 2 mm. When the thickness of the base member 21 is small, the base member 21 is sometimes called a sheet member or a film member.
  • the base member 21 is made of a non-conductive resin material or a non-conductive rubber material.
  • the resin material used for the base member 21 is, for example, at least one resin material selected from the group consisting of styrene-based resin, silicone-based resin (e.g., polydimethylpolysiloxane (PDMS)), acrylic-based resin, rotaxane-based resin, and urethane-based resin.
  • silicone-based resin e.g., polydimethylpolysiloxane (PDMS)
  • acrylic-based resin e.g., rotaxane-based resin
  • rotaxane-based resin e.g., rotaxane-based resin
  • urethane-based resin e.g., urethane-based resin.
  • the rubber material used for the base member 21 is, for example, at least one rubber material selected from the group consisting of silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.
  • the conductive elastic bodies 22 are disposed on the upper surface (the surface on the positive side of the Z axis) of the base member 21.
  • three conductive elastic bodies 22 are disposed on the upper surface of the base member 21.
  • the conductive elastic bodies 22 are elastic, conductive members.
  • Each conductive elastic body 22 has a long strip shape in the Z axis direction.
  • the three conductive elastic bodies 22 are disposed side by side at a predetermined interval in the X axis direction.
  • Wiring W2 electrically connected to the conductive elastic bodies 22 is provided at the end of each conductive elastic body 22.
  • the conductive elastic body 22 is formed on the upper surface of the base member 21 by a printing method such as screen printing, gravure printing, flexographic printing, offset printing, and gravure offset printing. These printing methods make it possible to form the conductive elastic body 22 on the upper surface of the base member 21 with a thickness of about 0.001 mm to 0.5 mm.
  • the conductive elastomer 22 is composed of a resin material with conductive filler dispersed therein, or a rubber material with conductive filler dispersed therein.
  • the resin material used for the conductive elastic body 22 is the same as the resin material used for the base member 21 described above, and is at least one resin material selected from the group consisting of, for example, styrene-based resins, silicone-based resins (polydimethylpolysiloxane (e.g., PDMS), etc.), acrylic-based resins, rotaxane-based resins, and urethane-based resins.
  • the rubber material used for the conductive elastomer 22 is the same as the rubber material used for the base member 21 described above, and is at least one type of rubber material selected from the group consisting of silicone rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.
  • silicone rubber isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, nitrile rubber, polyisobutylene, ethylene propylene rubber, chlorosulfonated polyethylene, acrylic rubber, fluororubber, epichlorohydrin rubber, urethane rubber, and natural rubber.
  • the conductive filler used in the conductive elastomer 22 is at least one material selected from the group consisting of metal materials such as Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In 2 O 3 (indium (III) oxide), and SnO 2 (tin (IV) oxide), conductive polymer materials such as PEDOT:PSS (i.e., a composite of poly 3,4-ethylenedioxythiophene (PEDOT) and polystyrene sulfonate (PSS)), and conductive fibers such as metal-coated organic fibers and metal wires (in a fibrous state).
  • metal materials such as Au (gold), Ag (silver), Cu (copper), C (carbon), ZnO (zinc oxide), In 2 O 3 (indium (III) oxide), and SnO 2 (tin (IV) oxide
  • conductive polymer materials such as PEDOT:PSS (i.e., a composite of poly 3,4-ethylenedi
  • FIG. 5(b) is a schematic perspective view showing the state in which conductor wire 23 is installed in the structure of FIG. 5(a).
  • the conductor wires 23 are linear members and are arranged overlapping on the upper surface of the conductive elastic body 22 shown in FIG. 5(a). In this embodiment, three conductor wires 23 are arranged overlapping on the upper surfaces of the three conductive elastic bodies 22. The three conductor wires 23 are arranged side by side at a predetermined interval in the longitudinal direction (Z-axis direction) of the conductive elastic body 22 so as to intersect with the conductive elastic body 22. Each conductor wire 23 extends in the X-axis direction so as to straddle the three conductive elastic bodies 22.
  • the conductor wires 23 are, for example, coated copper wires.
  • the conductor wire 23 is composed of a linear conductive member 23a and a dielectric 23b formed on the surface of the conductive member 23a.
  • the conductive member 23a is made of, for example, copper.
  • the conductive member 23a may be made of a twisted wire in which multiple core wires are twisted together.
  • the diameter of the conductive member 23a is, for example, about 60 ⁇ m.
  • the dielectric 23b has electrical insulation properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc.
  • the dielectric 23b is formed so as to cover the conductor wire 23 at least in the range of the conductor wire 23 that overlaps the conductive elastic body 22.
  • Figure 6(a) is a schematic perspective view showing the state in which thread 24 is installed in the structure of Figure 5(b).
  • each conductor wire 23 is connected to the base member 21 by threads 24 so as to be movable in the longitudinal direction (X-axis direction) of the conductor wire 23.
  • 12 threads 24 connect the conductor wires 23 to the base member 21 at positions other than the positions where the conductive elastic body 22 and the conductor wire 23 overlap.
  • the threads 24 are made of chemical fibers, natural fibers, or a mixture of these fibers.
  • FIG. 6(b) is a perspective view that shows a schematic diagram of the structure in FIG. 6(a) with a base member 25 installed.
  • the base member 25 is placed from above the structure shown in FIG. 6(a).
  • the base member 25 is an insulating member.
  • the base member 25 is, for example, at least one resin material selected from the group consisting of polyethylene terephthalate, polycarbonate, polyimide, etc.
  • the base member 25 may be made of the same material as the base member 21.
  • the base member 25 has a flat plate shape, and has the same size and shape as the base member 21 in a plan view.
  • the thickness of the base member 25 is, for example, 0.01 mm to 2 mm.
  • the four outer periphery sides of base member 25 are connected to the four outer periphery sides of base member 21 with threads 26.
  • This connection may be made with a silicone rubber adhesive.
  • This connection fixes base member 25 to base member 21.
  • conductor wire 23 is sandwiched between conductive elastic body 22 and base member 25.
  • the second load sensor 20 is completed as shown in Figure 6 (b).
  • the second load sensor 20 is installed on the surface of moving body 30 with an adhesive in a state in which it is turned over from the state shown in Figure 6 (b).
  • the conductor wire 23 When a load is applied to the surface of the base member 21, the conductor wire 23 is brought closer to the conductive elastic body 22 so that it is wrapped in the conductive elastic body 22. As a result, the contact area between the conductor wire 23 and the conductive elastic body 22 increases. This causes a change in the capacitance between the conductive member 23a and the conductive elastic body 22. By detecting the capacitance between the conductive member 23a and the conductive elastic body 22, the load applied to this area is obtained.
  • FIG. 7 is a plan view that shows a schematic diagram of the internal configuration of the second load sensor 20. For convenience, the thread 24 and the base member 25 are omitted from FIG. 7.
  • detection areas A11, A12, A13, A21, A22, A23, A31, A32, and A33 are formed at the positions where the three conductive elastic bodies 22 and the three conductor wires 23 intersect.
  • Each detection area includes the conductive elastic body 22 and the conductor wire 23 near the intersection of the conductive elastic body 22 and the conductor wire 23.
  • the conductor wire 23 constitutes one pole of the capacitance (e.g., an anode), and the conductive elastic body 22 constitutes the other pole of the capacitance (e.g., a cathode).
  • the conductor wire 23 is enveloped by the conductive elastic body 22. This changes the contact area between the conductor wire 23 and the conductive elastic body 22, and the capacitance between the conductor wire 23 and the conductive elastic body 22 changes.
  • the contact area between the conductive member 23a of the conductor wire 23 and the conductive elastic body 22 increases in the detection area A11 via the dielectric 23b.
  • the load applied in the detection area A11 can be calculated by detecting the capacitance between the conductive elastic body 22 that is most positive on the X-axis and the conductor wire 23 that is most positive on the Z-axis.
  • the load applied to the other detection areas can be calculated by detecting the capacitance between the conductive elastic body 22 and the conductor wire 23 that intersect in the other detection areas.
  • FIG. 8(a) is a perspective view that shows a base member 11 and a conductive elastic body 12 and a conductor wire 13 that are placed on the upper surface (the surface on the positive side of the Z axis) of the base member 11.
  • only one strip-shaped conductive elastic body 12 is disposed on the upper surface of a base member 11 that is rectangular in plan view.
  • the material and thickness of the base member 11 and the conductive elastic body 12 are the same as those of the base member 21 and the conductive elastic body 22 described above.
  • a wiring W1 that is electrically connected to the conductive elastic body 12 is disposed at the end of the conductive elastic body 12.
  • the conductor wire 13 is composed of a linear conductive member 13a and a dielectric 13b formed on the surface of the conductive member 13a.
  • the configuration of the conductor wire 13 is the same as that of the conductor wire 23 described above.
  • the conductor wire 13 is arranged to cross the conductive elastic body 12 so as to extend along the longitudinal direction of the conductive elastic body 12.
  • the conductive elastic body 12 is connected to the base member 11 by a thread 14 so as to be movable in the longitudinal direction.
  • FIG. 8(b) is a perspective view that shows a schematic diagram of the structure in FIG. 8(a) with a base member 15 installed.
  • the base member 15 is placed from above the structure shown in FIG. 8(a).
  • the base member 15 is an insulating member.
  • the base member 15 is made of the same material as the base member 25.
  • the base member 15 has a flat plate shape, and has the same size and shape as the base member 11 in a plan view.
  • the thickness of the base member 15 is the same as that of the base member 25 described above.
  • the four outer periphery sides of the base member 15 are connected to the four outer periphery sides of the base member 11 with threads 16. This connection may be made with a silicone rubber adhesive. This connection fixes the base member 15 to the base member 11. As a result, the conductor wire 13 is sandwiched between the conductive elastic body 12 and the base member 15. In this way, the first load sensor 10 is completed, as shown in Figure 8 (b).
  • the first load sensor 10 is installed on the moving body 30 by fixing the base member 15 to the side of the moving body 30 with an adhesive.
  • the method of detecting a load in the first load sensor 10 is the same as that of the second load sensor 20.
  • FIG. 9 is a block diagram showing the configuration of the circuit section of the robot hand 1.
  • the circuit configuration of the robot hand 1 includes a control unit 110, an arm driving unit 120, a hand driving unit 130, and processing units 140 and 150.
  • the control unit 110 includes a CPU, a microcomputer, etc., and controls each unit according to a preset control program.
  • the arm driving unit 120 includes drivers for driving each of the driving units 2e to 2i in FIG. 1, and drives the driving units 2e to 2i in response to control from the control unit 110.
  • the hand driving unit 130 includes drivers for driving each of the pair of claws 3a in FIG. 1, and drives the pair of claws 3a in response to control from the control unit 110.
  • the processing unit 140 performs processing on the load detector 4 arranged on one of the claws 3a.
  • the processing unit 140 includes a first load detection unit 141, a second load detection unit 142, and an acceleration sensor 9 installed on the load detector 4.
  • the first load detection unit 141 detects the load applied to the first load sensor 10 using the first load sensor 10 installed in the load detector 4. For example, the first load detection unit 141 detects the capacitance between the wiring W1 and the conductor wire 13 from the change in voltage between the wiring W1 and the conductor wire 13 when a predetermined voltage is applied between the wiring W1 and the conductor wire 13 in FIG. 8(b), and calculates the load applied to the first load sensor 10 from the detected capacitance. The first load detection unit 141 outputs the detected load to the control unit 110 at any time.
  • the second load detection unit 142 detects the load applied to the second load sensor 20 using the second load sensor 20 installed in the load detector 4.
  • the second load detection unit 142 has a detection circuit for selectively applying a voltage to a detection area to be measured among the nine detection areas in FIG. 7 and detecting the capacitance of the detection area.
  • the configuration of the detection circuit is, for example, incorporated by reference into the configuration of the detection circuit described in JP 2021-081341, which was previously filed by the applicant.
  • the second load detection unit 142 calculates the load applied to each detection area from the amount of static electricity detected for each detection area.
  • the second load detection unit 142 outputs the detected load to the control unit 110 at any time.
  • the processing unit 150 performs processing on the load detector 4 arranged on the other claw 3a. Like the processing unit 140, the processing unit 150 includes a first load detection unit 151, a second load detection unit 152, and an acceleration sensor 9 installed on the load detector 4.
  • the first load detection unit 151 and the second load detection unit 152 perform processing similar to that of the first load detection unit 141 and the second load detection unit 142 of the processing unit 140. That is, the processing of the first load detection unit 151 and the second load detection unit 152 differs from that of the first load detection unit 141 and the second load detection unit 142 only in that the first load sensor 10 and the second load sensor 20 are the processing targets.
  • the processing contents of the first load detection unit 151 and the second load detection unit 152 are the same as those of the first load detection unit 141 and the second load detection unit 142.
  • the control unit 110 controls the arm driving unit 120 and the hand driving unit 130 so that the item 5 is transported along the transport trajectory set by the upper controller 200. That is, the control unit 110 controls the arm driving unit 120 and the hand driving unit 130 so that the item 5 is gripped at the gripping position set by the upper controller 200. Furthermore, the control unit 110 controls the arm driving unit 120 and the hand driving unit 130 so that the item is transported along the movement trajectory set by the upper controller 200 to a release position, and the grip of the item is released at this release position. Such gripping position, release position and transport trajectory are set in the upper controller 200 by the user of the robot hand 1 via an operation terminal.
  • FIG. 10 is a graph that shows a schematic of the load acquired by the first load detection unit 141 when the gripped object 5 slips against the pair of claws 3a.
  • FIG. 10 shows the change in load detected by the lower first load sensor 10 in the load detector 4 on the left side of FIG. 3.
  • the load based on the weight of the moving body 30 itself is subtracted from the load detection result, and only the load based on the weight of the item 5 itself is detected.
  • the pulse waveform appears at the timing when the slippage of the article 5 stops during the stick-slip phenomenon described above, i.e., when the article 5 is fixed by being gripped by the pair of claws 3a.
  • the period when the pulse waveform does not appear corresponds to the period when the slippage of the article 5 occurs during the stick-slip phenomenon described above.
  • control unit 110 can determine whether or not the grasped item 5 is slipping based on whether or not such a waveform occurs in the load acquired from the first load sensor 10.
  • control unit 110 may determine that the grasped article 5 is slipping if such a waveform occurs continuously in the load acquired from at least one of the four first load sensors 10 shown in FIG. 4(b). Alternatively, the control unit 110 may determine that the grasped article 5 is slipping if such a waveform occurs continuously in the load acquired from at least one of the eight first load sensors 10 arranged in a pair of load detectors 4.
  • control unit 110 may use the acceleration detected by the acceleration sensor 9 to identify which of these first load sensors 10 is primarily bearing the load based on the weight of the article 5, and may determine that the grasped article 5 is slipping by referring only to the load obtained from the identified first load sensor 10.
  • the orientation of the hand 3 when grasping the article 5 can change to various directions. Therefore, the first load sensor 10 on which the weight of the article 5 is applied when the article 5 is grasped and lifted can differ depending on the orientation of the hand 3. In this case, the orientation of the hand 3 can be determined from the output of the acceleration sensor 9. Therefore, as described above, the control unit 110 can identify which of the four first load sensors 10 included in one load detector 4 is being subjected to a load based on the weight of the article 5, from the output of the acceleration sensor 9. The control unit 110 may refer only to the load acquired from the identified first load sensor 10, and determine that the grasped article 5 is slipping when a pulse-like waveform as shown in FIG. 10 appears continuously in this load.
  • the orientation of the hand 3 may be determined not from the output of the acceleration sensor 9, but from the state of movement of the hand 3 along a movement trajectory set by the upper controller 200. That is, the control unit 110 can calculate the orientation of the hand 3 when grasping the item 5 from the amount of rotation of the drive units 2e to 2i in FIG. 1. From the orientation of the hand 3 thus calculated, the control unit 110 may identify the first load sensor 10 on which the weight of the item 5 is applied when the item 5 is grasped and lifted. In this case, the acceleration sensor 9 may be omitted.
  • FIGS. 11(a) and (b) are diagrams explaining a method for detecting the weight of an item 5.
  • FIG. 11(a) shows only the first load sensor 10 and the moving body 30 of the configuration of the load detector 4
  • FIG. 11(b) shows only the first load sensor 10, the second load sensor 20, and the moving body 30 of the configuration of the load detector 4.
  • the orientation of the hand 3 when grasping and lifting the object 5 may change depending on the manner in which the robot hand 1 is used. Therefore, the orientation of the load detector 4 may also change depending on the change in the orientation of the hand 3.
  • the load L10 corresponding to the weight of the article 5 can be calculated from the loads L11 and L12 detected by the two lower first load sensors 10.
  • the load L11 is the load detected by the right first load sensor 10 of these two first load sensors 10.
  • the load L12 is the load detected by the left first load sensor 10 of these two first load sensors 10.
  • the load L10 can be calculated from the angle ⁇ 1 between the direction of the load L11 and the vertical downward direction using the following formula.
  • the angle ⁇ 1 can be calculated from the orientation of the hand 3 and the load detector 4.
  • the orientation of the hand 3 and the load detector 4 can be determined from the output from the acceleration sensor 9.
  • the orientation of the hand 3 and the load detector 4 can be determined from the movement state of the hand 3 along the movement trajectory set by the upper controller 200.
  • the control unit 110 therefore identifies the first load sensor 10 on which the weight of the article 5 is applied based on the output from the acceleration sensor 9, and calculates the load corresponding to the weight of the article 5 from the load detected by the identified first load sensor 10 using the above formula (1). In this calculation, the control unit 110 determines the orientation of the hand 3 and the load detector 4 based on the output from the acceleration sensor 9 or the movement trajectory from the upper controller 200, and calculates the angle ⁇ 1 formed by formula (1) from the determination result. The control unit 110 then obtains the weight corresponding to the load L10 from the correlation between the load L10 and the weight. This correlation can be set taking into account the weight of the moving body 30 itself, the frictional force between the moving body 30 and the recess 41, etc.
  • the load L11 is used to calculate the load L10, but the load L12 may be used to calculate the load L10.
  • the angle ⁇ 1 is obtained as the angle between the direction of the load L12 and the vertically downward direction.
  • the load L10 may be obtained by calculating the square root of the sum of the square of the load L11 and the square of the load L12.
  • the load L20 corresponding to the weight of the article 5 can be calculated from the load L21 detected by the lower first load sensor 10.
  • the load L21 is the load detected by the lower first load sensor 10
  • the load L22 is the load detected by the second load sensor 20.
  • the load L20 can be calculated from the angle ⁇ 2 between the direction of the load L21 and the vertical downward direction using the following formula.
  • the angle ⁇ 2 can be calculated based on the output from the acceleration sensor 9 or the movement trajectory from the upper controller 200.
  • the control unit 110 therefore identifies the first load sensor 10 on which the weight of the item 5 is applied based on the output from the acceleration sensor 9, and calculates the load corresponding to the weight of the item 5 from the load detected by the identified first load sensor 10 using the above formula (2).
  • the control unit 110 then obtains the weight corresponding to the load L20 from the correlation between the load L20 and the weight. As with the above, this correlation can be set taking into account the weight of the moving body 30 itself, the frictional force between the moving body 30 and the recess 41, etc.
  • the control unit 110 calculates the load L10 from the above formula (1) using the method described for Fig. 11(a), and calculates the load L20 from the above formula (2) using the calculated load L10 as the load L21 in Fig. 11(b). Then, the control unit 110 obtains the weight corresponding to the load L20 as the weight of the item 5 based on the correlation between the calculated load L20 and the weight.
  • the weight of the item 5 may be acquired from each of the load detectors 4 by the above method.
  • the control unit 110 acquires, for example, the weight obtained by averaging the weights acquired from the two load detectors 4 as the weight of the item 5.
  • FIG. 12 is a flowchart showing the control of the robot hand 1 during a grasping operation.
  • the control unit 110 brings the pair of claws 3a closer to each other to start the gripping operation (S101). At this time, the control unit 110 drives each claw 3a individually.
  • the control unit 110 temporarily stops driving that claw 3a. Then, when the second load sensor 20 arranged on the remaining claw 3a detects a load corresponding to contact with the article 5, the control unit 110 determines that the pair of claws 3a has pinched the article 5, and reduces the movement speed of the remaining claw 3a. This causes the detected load of the second load sensor 20 arranged on the pair of claws 3a to gradually increase.
  • the control unit 110 stops the movement of the pair of claws 3a and ends the gripping operation (S103).
  • the initial load L0 is set to be at least smaller than the maximum load Lmax compared in step S108.
  • the grip load is, for example, the average value of the loads detected by the second load sensors 20 arranged on each of the pair of load detectors 4. In this case, since the second load sensor 20 has nine detection areas A11 to A33 as shown in FIG. 7, the grip load is obtained as the average value of the loads obtained from a total of 18 detection areas.
  • the grip load may be the average load detected by one of the second load sensors 20.
  • the maximum load of the loads detected from a total of 18 detection areas may be obtained as the grip load.
  • control unit 110 moves the hand 3 upward at a low speed (S104). During this movement, the control unit 110 determines whether or not slippage of the article 5 due to its own weight has been detected (S105). Slippage is detected by the method described with reference to FIG. 10.
  • the control unit 110 determines whether the current gripping load detected by the second load sensor 20 is equal to or less than the maximum load Lmax previously set for this item 5 (S108).
  • the maximum load Lmax is set slightly lower than the upper limit of the load range in which the item 5 can be gripped without causing damage or other effects to the item 5. If the current gripping load exceeds the maximum load Lmax (S108: NO), the control unit 110 ends the processing of FIG. 12. At this time, the control unit 110 may send an error notification to the upper controller 200 indicating that the item 5 could not be gripped properly.
  • the control unit 110 narrows the gap between the pair of claws 3a by a predetermined amount (S109) and proceeds to step S105. This increases the gripping force on the article 5, and can prevent the article 5 from slipping.
  • the grip load to be determined in step S108 is not the average load described above, but rather, for example, the maximum value of the detected loads detected from a total of 18 detection areas arranged on the two second load sensors 20, or the maximum value of the detected loads detected from a total of 9 detection areas arranged on either one of the second load sensors 20. This makes it possible to reliably prevent damage to the item caused by the unevenly distributed maximum load when there is an uneven load distribution due to the shape of the item 5, etc.
  • the control unit 110 determines whether or not the weight of the article 5 has been detected (S106). Specifically, the control unit 110 determines whether or not the weight obtained from the load detected by the first load sensor 10 is within the range of weight that should be detected when the article 5 is properly gripped. The weight of the article 5 is calculated by the method described with reference to Figures 11 (a) and (b).
  • the control unit 110 determines whether the current grip load detected by the second load sensor 20 is equal to or greater than the minimum load Lmin previously set for this item 5 (S110).
  • the minimum load Lmin is set slightly higher than the lower limit of the load range in which the item 5 can be gripped without causing damage or other effects to the item 5.
  • the control unit 110 widens the gap between the pair of claws 3a by a predetermined amount (S110) and proceeds to step S112. On the other hand, if the current grip load is less than the minimum load Lmin (S110: NO), the control unit 110 proceeds to step S112 without widening the gap between the pair of claws 3a by the predetermined amount.
  • step S106 the reason why the weight cannot be detected in step S106 is that the gripping force of the hand 3 is strong, so that the moving body 30 is pressed strongly against the bottom surface of the recess 41, and the moving body 30 does not move downward due to the weight of the article 5.
  • the distance between the pair of claws 3a is widened by a predetermined amount in step S111, the pressing of the moving body 30 against the bottom surface of the recess 41 is weakened, and the moving body 30 becomes more likely to move downward due to the weight of the article 5. This makes it easier for a load corresponding to the weight of the article 5 to be applied to the first load sensor 10, and makes it easier to detect the weight of the article 5.
  • step S112 the control unit 110 determines whether a preset time has elapsed since the hand 3 began to rise in step S104. If the determination in step S112 is NO, the control unit 110 returns the process to step S105 and repeats the above process. Thereafter, if the control unit 110 detects the weight of the item 5 (S106: YES) without detecting any slippage of the item (S105: NO), the control unit 110 determines whether the hand 3 has risen to a predetermined height (S107).
  • the predetermined height is the height to which the hand 3 rises during the period in which it is determined that the item 5 has been stably grasped with an appropriate gripping force and raised. If the determination in step S107 is NO, the control unit 110 returns the process to step S112 and repeats the same process. Thereafter, if the determination in step S107 becomes YES, the control unit 110 ends the process in FIG. 12 and proceeds to the subsequent operation of transferring the item 5.
  • step S106 the weight of the item 5 is detected in step S106 in order to avoid, for example, determining that the item 5 has been properly grasped when it has already slipped off.
  • step S105 if slippage is detected in step S105, the gripping force is increased by the processing of steps S108 and S109, but it is possible that the article 5 will slip off the pair of claws 3a before the gripping force is sufficiently increased by this processing. In this case, the load detected by the first load sensor 10 will no longer change to the waveform shown in Figure 10. For this reason, the determination in step S105 will be NO, and without the determination step of step S106, it will be erroneously determined that the article 5 has been properly gripped and raised to the specified height.
  • step S106 executes the process of step S106. That is, if the article 5 has already slipped off the hook 3a as described above, the determination of step S106 will not become YES until a timeout occurs in step S112. Therefore, in this case, the determination of step S112 will then become YES, and the process of FIG. 12 will end.
  • control unit 110 may also send an error notification to the host controller 200 indicating that the weight of the item 5 could not be properly detected. This allows the user to understand that a problem has occurred with the operation of the robot hand 1.
  • the load detector 4 Since the load detector 4 is equipped with the first load sensor 10, when an object is grasped and lifted by the multiple claws 3a, it is possible to determine whether the object 5 has slipped relative to the claws 3a based on whether the load obtained from the first load sensor 10 varies with the object's fixation and slippage, i.e., the stick-slip phenomenon (see FIG. 10). This makes it possible to reduce the number of load sensors arranged in the load detector 4 for slippage detection, and to simplify the configuration. Furthermore, since it is only necessary to determine whether the load varies with the stick-slip phenomenon, slippage of the object 5 can be detected by simple processing.
  • the load detector 4 has first load sensors 10 disposed at multiple positions between the outer surface of the moving body 30 and the inner surface of the recess 41. More specifically, when the moving body 30 is viewed from above, a pair of first load sensors 10 are disposed at positions sandwiching the moving body 30, and another pair of first load sensors 10 are disposed at other positions sandwiching the moving body 30 in a direction intersecting a straight line connecting the pair of first load sensors 10.
  • the orientation of the load detector 4 changes, for example, as shown in FIG. 11(a)
  • one of the first load sensors 10 can detect a load corresponding to the weight of the article 5. Therefore, even if the orientation of the load detector 4 changes, it is possible to properly detect whether or not slippage has occurred in the article 5 depending on whether or not a fluctuation corresponding to the stick-slip phenomenon has occurred in the detected load.
  • the first load sensor 10 includes a conductive elastic body 12, a linear conductive member 13a, and a dielectric 13b interposed between the conductive elastic body 12 and the conductive member 13a.
  • the load applied to the first load sensor 10 can be detected by measuring the capacitance between the conductive elastic body 12 and the conductive member 13a using a detection circuit.
  • a second load sensor 20 is installed on the surface of the moving body 30, and an anti-slip member 50 is disposed on the surface of the moving body 30 via the second load sensor 20.
  • the second load sensor 20 can detect a load corresponding to the gripping force of the item 5.
  • the second load sensor 20 has multiple detection areas A11 to A33. More specifically, the multiple detection areas A11 to A33 are arranged in a matrix. This allows the load to be detected individually for each detection area, and the load distribution to be detected. Therefore, when the load detector 4 is installed as shown in FIG. 3, the distribution of the gripping force (load) applied to the item 5 can be detected. Therefore, based on this distribution, it is possible to prevent, for example, an excessive and unevenly distributed gripping force from being applied to the item 5.
  • the second load sensor 20 comprises a conductive elastic body 22, a linear conductive member 23a, and a dielectric 23b interposed between the conductive elastic body 22 and the conductive member 23a.
  • the load applied to the second load sensor 20 can be detected by measuring the capacitance between the conductive elastic body 22 and the conductive member 23a using a detection circuit.
  • multiple detection areas A11 to A33 can be easily set as shown in Figure 7.
  • the load detector 4 includes a restricting member 60 for restricting the moving body 30 from slipping out of the recess 41.
  • the load detector 4 when the load detector 4 is installed on the claw 3a of the robot hand 1 as shown in FIG. 3, the moving body 30 can be kept stably accommodated in the recess 41 even if the orientation of the robot hand 1 changes.
  • the load detector 4 further includes a dustproof member 70 for preventing dust from entering between the moving body 30 and the recess 41. This makes it possible to prevent malfunctions of the load detector 4 caused by dust entering between the moving body 30 and the recess 41.
  • the load detector 4 is provided with a configuration (self-lubricating, lubricant, multiple hemispherical protrusions, multiple semi-cylindrical ridges, etc.) that facilitates movement of the moving body 30 relative to the recess 41. This makes it easier for the weight of the grasped item 5 to be transmitted to the first load sensor 10. This allows the slippage and weight of the item 5 to be detected smoothly.
  • a second load sensor 20 for detecting the load in the gripping direction is disposed on the load detector 4 installed on each pair of claws 3a, and as shown in Figure 12, the control unit 110 adjusts the gripping strength of the pair of claws 3a (S109, S111) based on the load obtained from the second load sensor 20 within a range in which the article 5 does not slip (S105: NO). This allows the gripping force of the pair of claws 3a to be adjusted to an appropriate gripping force (a gripping force that is neither too strong nor too weak) that does not cause the article 5 to slip.
  • the control unit 110 adjusts the gripping strength of the pair of claws 3a (S111) to a level that does not cause the article 5 to slip (S105: NO, but allows the first load sensor 10 to detect the weight of the article 5 (S105: YES). This makes it possible to detect the weight of the gripped article 5, and prevents the state in which the article 5 has slipped off the claws 3a from being erroneously determined to be an appropriate gripping state, as described above.
  • the control unit 110 adjusts the gripping strength of the pair of claws 3a so as not to exceed a preset maximum load Lmax for the article 5 (S109). This makes it possible to set the gripping strength of the pair of claws 3a to an optimal gripping strength that prevents the article 5 from slipping while avoiding damage to the article 5.
  • the load detectors 4 are provided on both of the pair of claws 3a, but the load detectors 4 do not need to be provided on all of the claws 3a.
  • FIG. 13 is an enlarged side view showing the configuration near a pair of claws 3a in modification example 1.
  • a load detector 4 is installed only on the claw 3a on the positive side of the Y axis, and the load detector 4 is omitted on the other claw 3a.
  • the other claw 3a is formed with a protrusion 3a1 that protrudes in the positive direction of the Y axis to make it easier to grip an item 5, and furthermore, an anti-slip member 51 is installed on the surface of this protrusion 3a1 on the positive side of the Y axis.
  • the surface of the protrusion 3a1 on the positive side of the Y axis is a plane parallel to the X-Z plane.
  • the weight of the article 5 can be calculated from the load detected by the first load sensor 10 using the method described with reference to FIGS. 11(a) and (b).
  • step S101 in FIG. 12 differs from the above embodiment. That is, regardless of which of the pair of claws 3a has reached the article 5, the control unit 110 continues to control the pair of claws 3a to approach each other until the determination in step S102 becomes YES. In this case, when one of the pair of claws 3a reaches the article 5 first, the article 5 is pushed and moved by the subsequent driving of this claw 3a. Thereafter, the other claw 3a reaches the article 5, and the article 5 is sandwiched between the pair of claws 3a. Then, when the load detected by the second load sensor 20 of the load detector 4 reaches the initial load L0 (step S102: YES), the pair of claws 3a is stopped and the gripping operation ends (S103).
  • step S105 onward in FIG. 12 may be performed in the same manner as in the above embodiment, based on the load detection results using the load detector 4 (first load sensor 10, second load sensor 20) installed on the claw 3a on the positive side of the Y axis. This can achieve the same effects as in the above embodiment 1.
  • both the first load sensor 10 and the second load sensor 20 are disposed in the load detector 4 , but only the first load sensor 10 may be disposed in the load detector 4 .
  • FIG. 14 is an enlarged side view showing the configuration near a pair of claws 3a in modified example 2.
  • the second load sensor 20 is omitted from the load detector 4 on the positive side of the Y axis, and instead a spacer 80 is installed on the surface of the negative side of the Y axis of the moving body 30.
  • the anti-slip member 50 is installed on the surface of the spacer 80 on the negative side of the Y axis.
  • the spacer 80 has the same size and shape as the second load sensor 20 in a plan view, and has a constant thickness.
  • the spacer 80 is made of a hard material such as resin. Instead of the spacer 80, a protrusion of a constant height may be formed in an area of the moving body 30 that corresponds to the spacer 80 on the negative side of the Y axis.
  • the claw 3a on the negative side of the Y axis is formed with a protrusion 3a1, similar to the first modification in FIG. 13.
  • the second load sensor 20 is installed on the surface of the protrusion 3a1 on the positive side of the Y axis, and further, the anti-slip member 50 is installed on the surface of the second load sensor 20 on the positive side of the Y axis.
  • the slippage and weight of the article 5 can be detected by the detected load by the first load sensor 10 arranged on the load detector 4. Also, the gripping load when gripping the article 5 is detected by the second load sensor 20 arranged on the claw 3a on the negative side of the Y axis. As in Modification Example 1, the processing of FIG. 12 may be performed based on the results of load detection by the first load sensor 10 and the second load sensor 20. This can achieve the same effects as in the above-mentioned embodiment 1.
  • FIG. 15A is a diagram showing a configuration of a structure for forming the first load sensor 10 and the second load sensor 20 according to the third modified example.
  • the base member 21 is omitted from the illustration.
  • the base member 21 has the same shape and size as the base member 25.
  • the base member 21 is connected to the base member 25 by a thread 26.
  • FIG. 16 is a perspective view showing the structure of FIG. 15(a) placed over the moving body 30.
  • FIG. 15(a) The structure in FIG. 15(a) is placed on the top surface of the moving body 30 so that the base member 25 faces the top surface of the moving body 30, and then the portions protruding on the positive and negative Z-axis and the portions protruding on the positive and negative X-axis are folded so as to fit along the sides of the moving body 30. At this time, the base member 25 is fixed to the top surface and each side of the moving body 30 with adhesive. This completes the load detector 4 as shown in FIG. 16. As in FIG. 15(a), the base member 21 is also omitted in FIG. 16. That is, the top surface and each side of FIG. 16 are further overlapped by the base member 21.
  • the second load sensor 20 is formed by the area on the top surface surrounded by the dashed line. Furthermore, the first load sensor 10 is formed by each of the four side surface areas.
  • the conductive elastic body 22 is shared as the conductive elastic body of the first load sensor 10 formed on the positive and negative sides of the Z axis. In this case, by shifting the timing of applying a voltage between the conductor wire 23 and the conductive elastic body 22 from the timing of applying a voltage between the conductor wire 13 and the conductive elastic body 22, the loads applied to the first load sensor 10 and the second load sensor 20 can be obtained separately.
  • the first load sensor 10 configured on the positive and negative sides of the Z axis has three detection areas because three conductive elastic bodies 22 cross one conductor wire 13.
  • the first load sensor 10 configured on the positive and negative sides of the X axis has one detection area. Therefore, in this configuration, processing is required to uniformly treat the load detected by the first load sensor 10 configured on the positive and negative sides of the Z axis and the load detected by the first load sensor 10 configured on the positive and negative sides of the X axis.
  • control unit 110 averages the loads detected in the three detection areas of each of the first load sensors 10 configured on the positive and negative sides of the Z axis, calculates the loads of these first load sensors 10, and performs a process of adjusting the level of the calculated load and the loads detected by the first load sensors 10 configured on the positive and negative sides of the X axis.
  • the load detector 4 of the modified example 3 When the load detector 4 of the modified example 3 is used, the same control as in the above embodiment can be performed. Therefore, the modified example 3 can also achieve the same effect as in the above embodiment.
  • FIG. 15(a) may be further modified as shown in FIG. 15(b).
  • a load detector 4 equipped with four first load sensors 10 and one second load sensor 20 can be configured by bending the parts protruding in the X-axis positive and negative directions and the parts protruding in the Z-axis positive and negative directions in the structure of Fig. 15(b) so as to fit along the four side faces of the moving body 30.
  • the first load sensor 10 may be placed only in the gap on the negative side of the Z axis, as shown in FIG. 17(a).
  • slippage of the item 5 can be detected from the load detected by this first load sensor 10 using the method of FIG. 10.
  • the load detector 4 since the load detector 4 is not tilted as in FIGS. 11(a) and (b), the weight of the item 5 can be obtained directly from the load detected by this first load sensor 10.
  • the acceleration sensor 9 may be omitted.
  • the upper first load sensor 10 may be omitted and only the lower and left/right first load sensors 10 may be placed on the load detector 4, as shown in FIG. 17(b). In this case, the slippage and weight of the article 5 can be detected in the same manner as in the first embodiment above.
  • the load detector 4 has a rectangular shape in a plan view, but the shape of the load detector 4 is not limited to this.
  • the shape of the load detector 4 in a plan view may be circular.
  • the second load sensor 20, the moving body 30, the support body 40, the recess 41, the anti-slip member 50, the regulating member 60, and the dustproof member 70 are all circular in a plan view.
  • the second load sensor 20 and the anti-slip member 50 may be rectangular instead of circular in a plan view.
  • the moving body 30 may rotate in a direction parallel to the X-Z plane, causing the positions of the four first load sensors 10 to change.
  • two cylindrical protrusions 42 that protrude in the Y-axis direction are formed on the bottom surface of the recess 41, and a circular recess 31 into which these protrusions 42 are inserted may be formed on the underside of the moving body 30.
  • the inner diameter of the recess 31 is slightly larger than the outer diameter of the protrusions 42. This allows the moving body 30 to move in a direction parallel to the X-Z plane within the range required for the first load sensors 10 to detect the load.
  • the shape of the load detector 4 in a plan view may be other than a circle.
  • the object 5 is gripped by two claws 3a, but the object 5 may be gripped by three or more claws 3a.
  • the load detector 4 may be installed on all the claws 3a, or the load detector 4 may be arranged on at least one of the claws 3a.
  • the load detector 4 may be installed on any one of the claws 3a.
  • the load detector 4 having only the first load sensor 10 may be installed on at least one of the claws 3a
  • the second load sensor 20 and the anti-slip member 50 may be installed on at least one of the remaining claws 3a.
  • the load detector 4 having only the first load sensor 10 may be installed on any one of the claws 3a
  • the second load sensor 20 and the anti-slip member 50 may be installed on any other one of the claws 3a.
  • an acceleration sensor 9 is disposed on each of the two load detectors 4, but one of these acceleration sensors 9 may be omitted. In this case, it is sufficient that the orientations of the two load detectors 4 are detected from the output of one acceleration sensor 9.
  • the number of detection areas arranged on the second load sensor 20 is not limited to this.
  • the detection areas arranged on the second load sensor 20 do not necessarily have to be arranged in a matrix, and may be arranged in only one row, for example.
  • multiple detection areas do not necessarily have to be arranged on the second load sensor 20, and similar to the first load sensor 10, only one detection area may be arranged on the second load sensor 20.
  • the conductive elastic bodies 12, 22 are arranged only on the base members 11, 21, but the conductive elastic bodies may also be arranged on the base members 15, 25.
  • the conductive elastic bodies are arranged on the base members 15, 25 in areas corresponding to the conductive elastic bodies 12, 22 in a plan view.
  • the conductive elastic bodies facing each other are electrically connected.
  • the restricting member 60 does not necessarily have to be a frame-plate-shaped member, as long as it is capable of restricting the moving body 30 from slipping out of the recess 41.
  • the restricting member may be configured to cover multiple locations of the moving body 30 (for example, the middle positions of each side).
  • a load detector comprising:
  • a load detector comprising:
  • a load detector comprising:
  • the load sensor includes a conductive elastic body, a linear conductive member, and a dielectric body interposed between the conductive elastic body and the conductive member.
  • a load detector comprising:
  • This technology makes it possible to detect the load applied to the load sensor by measuring the capacitance between the conductive elastic body and the conductive member using a detection circuit.
  • a load detector comprising:
  • the load corresponding to the gripping force of the item can be detected by another load sensor.
  • a load detector comprising:
  • a load detector comprising:
  • This technology makes it possible to detect the load for each detection area individually, and detect the distribution of the load. This makes it possible to detect the distribution of the gripping force (load) applied to an item. Therefore, based on this distribution, it is possible to prevent, for example, an excessive and unevenly distributed gripping force from being applied to an item.
  • the other load sensor includes a conductive elastic body, a linear conductive member, and a dielectric body interposed between the conductive elastic body and the conductive member.
  • a load detector comprising:
  • the load applied to another load sensor can be detected by measuring the capacitance between the conductive elastic body and the conductive member using a detection circuit.
  • multiple detection areas can be easily set by crossing multiple conductive members over multiple conductive elastic bodies.
  • a load detector comprising:
  • the moving object can continue to be stably accommodated in the recess.
  • a load detector comprising:
  • This technology can prevent malfunctions of the load detector caused by dust getting between the moving body and the recess.
  • a load detector comprising:
  • This technology makes it easier for the weight of the grasped object to be transmitted to the first load sensor. This makes it possible to smoothly detect the slippage and weight of the object.
  • the load detector according to the first aspect of the present invention is disposed on at least one of the claws so that the anti-slip member comes into contact with the article when the article is gripped; and a control unit that determines whether or not the article is slipping relative to the claws based on whether or not a change occurs in the load obtained from the load sensor in response to fixation and slipping of the article when the article is gripped and lifted by the multiple claws.
  • a robot hand characterized by
  • This technology allows the gripping force of the claws to be adjusted to an appropriate gripping force (a gripping force that is neither too strong nor too weak) that prevents the item from slipping.
  • the control unit adjusts the gripping strength of the plurality of claws to a strength that allows the load sensor to detect the weight of the article without causing slippage of the article.
  • This technology makes it possible to detect the weight of a grasped object.
  • the control unit adjusts the gripping strength of the plurality of claws so as not to exceed a preset maximum load on the article.
  • This technology makes it possible to set the gripping force of the claws to an optimal level that prevents the item from slipping while avoiding damage to the item.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Robotics (AREA)
  • Mechanical Engineering (AREA)
  • Manipulator (AREA)

Abstract

Le détecteur de charge (4) de l'invention comprend : un corps mobile (30) avec une épaisseur prédéterminée ; un corps de support (40) avec une section de cavité (41) pour loger le corps mobile (30) de sorte que le corps mobile puisse se déplacer dans une direction perpendiculaire au sens de l'épaisseur ; un premier capteur de charge (10) interposé entre une surface latérale externe du corps mobile (30) et une surface latérale interne de la section de cavité (41) ; et un élément antidérapant (50) disposé sur une surface du corps mobile (30), la surface se trouvant sur le côté opposé à la surface inférieure de la section de cavité (41). Le détecteur de charge (4) est installé sur une griffe (3a) d'un organe de préhension de sorte que l'élément antidérapant (50) entre en contact avec un article (5) lorsque l'article (5) est saisi.
PCT/JP2023/024092 2022-10-24 2023-06-28 Détecteur de charge et organe de préhension WO2024089940A1 (fr)

Applications Claiming Priority (2)

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JP2022-170217 2022-10-24
JP2022170217 2022-10-24

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6156539U (fr) * 1984-09-19 1986-04-16
US4745812A (en) * 1987-03-25 1988-05-24 The United States Of America As Represented By The Secretary Of The Army Triaxial tactile sensor
JP2004268160A (ja) * 2003-03-05 2004-09-30 Sharp Corp ロボットハンドおよびその制御方法
CN205271571U (zh) * 2015-12-30 2016-06-01 湖南机电职业技术学院 一种自动化制造用机械手臂
WO2018096901A1 (fr) * 2016-11-25 2018-05-31 パナソニックＩｐマネジメント株式会社 Élément sensible à la pression et dispositif de direction
JP2019051569A (ja) * 2017-09-14 2019-04-04 株式会社東芝 保持装置、ハンドリング装置、および検出装置
JP2021122925A (ja) * 2020-02-10 2021-08-30 豊田合成株式会社 ロボットハンド

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6156539U (fr) * 1984-09-19 1986-04-16
US4745812A (en) * 1987-03-25 1988-05-24 The United States Of America As Represented By The Secretary Of The Army Triaxial tactile sensor
JP2004268160A (ja) * 2003-03-05 2004-09-30 Sharp Corp ロボットハンドおよびその制御方法
CN205271571U (zh) * 2015-12-30 2016-06-01 湖南机电职业技术学院 一种自动化制造用机械手臂
WO2018096901A1 (fr) * 2016-11-25 2018-05-31 パナソニックＩｐマネジメント株式会社 Élément sensible à la pression et dispositif de direction
JP2019051569A (ja) * 2017-09-14 2019-04-04 株式会社東芝 保持装置、ハンドリング装置、および検出装置
JP2021122925A (ja) * 2020-02-10 2021-08-30 豊田合成株式会社 ロボットハンド

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