Holding device and method for judging holding state

Abstract

In a gripping device capable of gripping an article by a bag body using a blocking phase change, a gripping device capable of judging a gripping state of an article with a simple configuration is provided. The gripping device (10) capable of gripping an article (MO) includes a driving section (12), a support member (13) capable of acting by the driving section (12), a detection section (14) that detects a voltage, a bag body (40) provided to the support member (13) and formed of an elastic body, capable of elastically deforming in accordance with a shape of the article (MO), capable of sensing a contact pressure accompanying contact with the article (MO) and outputting a voltage toward the detection section (14), a mixture (CM) housed in the bag body (40) and composed of a particle (CP) and a fluid (CA), and a pressure adjustment section (20) that adjusts a pressure of the fluid (CA) housed in the bag body (40) in a state of maintaining a shape of the bag body (40).

Description

Technical Field

[0001] This invention relates to a gripping device and a method for determining the gripping state. Background Technology

[0002] As a gripping device with a clamp utilizing jamming transition, a device as described in Japanese Patent Application Publication No. 2013-523478 (hereinafter, Patent Document 1) is known. The device described in Patent Document 1 is a passive clamping and releasing device, comprising a deformable membrane, at least one interface, and granular material. The deformable membrane has an opening that is fluidly connected to a source of fluid inlet and outlet in a drainable, sealed relationship. The at least one interface provides a source of fluid inlet and outlet configured in fluid connection with the opening of the membrane. The granular material is disposed within the membrane. Summary of the Invention

[0003] The problem that the invention aims to solve This gripper, utilizing a blocking phase change mechanism, presses an object to be held into the surface of a bag (equivalent to the membrane in Patent Document 1) containing a fluid-like mixture (equivalent to the granular material in Patent Document 1), thereby achieving an elastically deformed state that matches the shape of the object. Thus, in this elastically deformed state where the object is trapped, the mixture within the bag changes from a fluid-like state to a solid-like state, allowing the gripper to move and hold the object. This gripper, utilizing a blocking phase change mechanism, can deform into various shapes to hold objects of various forms, as long as it allows the object to be trapped and elastically deformed within the bag.

[0004] In gripping devices with robotic arms capable of holding objects using multiple actuators, one known method for determining the gripping state of the robotic arm is using a mechanical device such as a pressing button. The mechanical device is mounted on the robotic arm. The mechanical device outputs a voltage upon contact with the object. The gripping device with the robotic arm determines the gripping state based on the detection result of the voltage output from the mechanical device upon contact with the object. However, when the mechanical device is mounted on a bag using a gripper that utilizes a blocking phase change mechanism, there is a risk that the bag may not deform into a shape capable of holding the object due to the rigidity of the mechanical device. On the other hand, as a method for determining the gripping state of a gripper utilizing a blocking phase change mechanism, the configuration of the determination system using this method becomes more complex compared to the case using a mechanical device when optical equipment such as a camera is used.

[0005] The purpose of this disclosure is to provide a gripping device that can grip an article by utilizing a bag body that blocks phase change, and which can determine the gripping state of the article with a simple configuration.

[0006] Furthermore, the purpose of this disclosure is to provide a method for determining the holding state with a simple configuration when holding an article based on a bag that utilizes a blocking phase change.

[0007] Methods for solving problems The present disclosure provides a gripping device capable of gripping an article, the gripping device comprising: Drive unit; A support member that can be actuated by the drive unit; The detection unit detects voltage; The bag body is disposed on the support member and is formed of an elastic body, capable of elastically deforming to match the shape of the article, and the bag body is capable of sensing the contact pressure accompanying contact with the article and outputting voltage toward the detection unit; A mixture, contained within the bag body, and composed of particles and fluid; and The pressure adjustment unit adjusts the pressure of the fluid contained in the bag body while maintaining the shape of the bag body.

[0008] Another aspect of this disclosure is a method for determining the holding state, wherein, By bringing a bag containing a mixture of particles and fluid, and containing a predetermined amount of the fluid, into contact with the article, the bag elastically deforms in a sealed state that matches the shape of the article, and outputs voltage from the bag. While maintaining the airtight seal of the bag, the mixture is depressurized to block the phase transition, thereby causing the bag to transition from a softened state to a hardened state and hold the item. The voltage value output from the bag body when the bag body transitions from a softened state to a hardened state is stored as a reference value. The holding state of the bag is determined by confirming whether the difference between the voltage value output from the hardened bag and the reference value exceeds a predetermined threshold.

[0009] Invention Effects According to the gripping device disclosed herein, a gripping device is provided that can grip an article by utilizing a bag body with a blocking phase change, and can determine the gripping state of the article with a simple configuration.

[0010] According to the method for determining the holding state disclosed herein, when holding an article based on a bag that utilizes a blocking phase change, a method for determining the holding state with a simple configuration can be provided. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the holding device involved in the embodiment.

[0012] Figure 2 This is a block diagram of the holding device involved in the implementation method.

[0013] Figure 3 This is a schematic diagram of the holding device involved in the modified example.

[0014] Figure 4 This is a schematic diagram of the holding device involved in the modified example.

[0015] Figure 5 This is a schematic diagram showing the state of the gripping device according to the embodiment before it grips the article.

[0016] Figure 6 This is a schematic diagram showing the state in which the holding device according to the embodiment holds the article.

[0017] Figure 7 This is a schematic diagram showing the state in which the gripping device according to the embodiment grips the item and leaves the worktable.

[0018] Figure 8 This is a schematic diagram showing the state of the object held by the holding device according to the embodiment after it has fallen off.

[0019] Figure 9 This is a flowchart illustrating the sequence of the methods for determining the holding state involved in the implementation method.

[0020] Symbol Explanation 10 Holding device, 11 Control unit, 11a Storage unit, 11b Judgment unit, 12 Drive unit, 13 Support member, 14 Detection unit, 20 Fluid control unit (an example of a pressure adjustment unit), 30 Clamp, 40 Bag body, 42 Main body, 50 Pressure sensing unit, 52 Piezoelectric membrane, 53 Pressure sensor, CM Mixture, CP Particles, CA Fluid, MO Article. Detailed Implementation

[0021] The embodiments disclosed herein will now be described with reference to the accompanying drawings. The scaling of the drawings may not be accurate, and some features may be exaggerated or omitted.

[0022] In the following explanation, the vertical direction (up and down) is referred to as the X direction. Additionally, the vertical upward direction is referred to as the +X direction, and the vertical downward direction is referred to as the -X direction.

[0023] like Figure 1 As shown, the gripping device 10 involved in this disclosure is a multi-joint robot, which is capable of gripping an item MO placed on a workbench TA and moving it to a workbench (not shown) at its destination.

[0024] like Figure 1 As shown, the gripping device 10 includes a drive unit 12, a support member 13, a clamp 30, a detection unit 14, and a control unit 11. Figure 2 As shown, the holding device 10 also has a notification unit 15.

[0025] The drive unit 12 in this embodiment includes a motor (not shown) and a gearbox. The drive unit disclosed herein may also include a linear actuator. The operation of the motor in the drive unit 12 is controlled by the control unit 11.

[0026] The support member 13 is a column extending in one direction. The support member 13 has a first end 13a and a second end 13b. The first end 13a is connected to the drive unit 12. The second end 13b is located on the side opposite to the first end 13a. The support member 13 is actuated by the drive unit 12.

[0027] In the gripping device 10 of the embodiment, the drive unit 12 is also connected to other support members (not shown) and other drive units.

[0028] like Figure 1 As shown, the gripper 30 is connected to the second end 13b. The gripper 30 is capable of holding the item MO. Details of the gripper 30 will be described later.

[0029] The detection unit 14 detects the voltage output from the clamp 30. The detection unit 14 can send the detected voltage value to the control unit 11.

[0030] The notification unit 15 notifies the holder 10 of its status. The notification unit 15 may be, for example, a display monitor. The notification unit 15 may also be a warning light. The notification unit 15 may also have an audio output function.

[0031] The control unit 11 controls the various parts of the gripping device 10. Specifically, such as... Figure 2 As shown, the control unit 11 controls the operation of the drive unit assembly, the notification unit 15, and the gripper 30. The drive unit assembly consists of multiple drive units, including the drive unit 12. By controlling the operation of the drive unit assembly using the control unit 11, the gripping device 10 can move the gripper 30 closer to the item MO. Details of the control unit 11 will be described later.

[0032] <Clamping Device 30> like Figure 1 As shown, the clamp 30 has a base 32, a cover 34, a bag body 40, a hybrid body CM, a plug 36, and a fluid control part 20.

[0033] The base 32 is box-shaped. The base 32 is connected to the second end 13b of the support member 13. In this embodiment, one side of the base 32 facing the second end 13b is connected to the second end 13b. The base 32 supports various parts of the clamp 30. The base 32 can accommodate various parts of the clamp 30 internally. In this embodiment, the base 32 can accommodate the terminal portion 50a, the interface portion 36a, and the piping 25, which will be described later.

[0034] The cover 34 is provided on a side of the base 32 facing a direction different from that of the support member 13. In this embodiment, the cover 34 is provided on a side of the base 32 facing the side opposite to the second end 13b of the support member 13. The cover 34 is a bowl-shaped structure that opens towards the side opposite to the base 32. The cover 34 has a hole 35. The hole 35 extends through the cover 34 along its central axis. The hole 35 supports the outer surface of the opening 44 of the bag body 40 (described later). The cover 34 exposes the receiving portion 46 of the bag body 40 through the opening of the bowl-shaped cover 34. Thus, the shape of the bag body 40 supported by the cover 34 is formed in the shape of a round-bottomed container with a narrowed opening 44. The cover 34 protects the area around the opening 44 of the bag body 40.

[0035] The plug 36 is cylindrical. The plug 36 is configured to contact the inner surface of the opening 44 of the bag body 40. The plug 36 seals the inner surface of the opening 44, supported by the hole 35, through its cylindrical side surface. In this embodiment, the plug 36, when positioned within the opening 44, is secured to the cover 34 or the base 32 using a connecting member (not shown) including bolts.

[0036] The plug portion 36 has an interface portion 36a. The interface portion 36a is a tubular structure that allows fluid CA to pass between the inside of the bag body 40 sealed by the plug portion 36 (the receiving portion 46 side described later) and the outside of the bag body 40. The interface portion 36a has a filter portion 36b and a connecting end 36c.

[0037] A filter section 36b is provided at the end of the interface section 36a facing the receiving section 46 of the bag body 40. The filter section 36b allows the passage of fluid CA. The filter section 36b prevents the passage of particulate matter CP.

[0038] The connecting end 36c is the end of the interface portion 36a on the side opposite to the filter portion 36b. The connecting end 36c is connected to the piping 25 of the fluid control portion 20, which will be described later.

[0039] The fluid control unit 20 controls the amount of fluid CA contained within the bag body 40 through the interface 36a. The fluid control unit 20 adjusts the pressure of the fluid CA contained within the bag body 40. That is, the fluid control unit 20 adjusts the pressure within the bag body 40. The fluid control unit 20 is an example of a pressure regulating unit. The fluid control unit 20 is capable of creating a vacuum state within the bag body 40.

[0040] The fluid control unit 20 includes a pump unit 24, piping 25, a tank unit 26, and piping 27.

[0041] Pump unit 24 allows fluid CA to flow out or into the connection target of the piping via a pipe connected to pump unit 24. The operation of pump unit 24 is controlled by control unit 11.

[0042] That is, the operation of the fluid control unit 20 is controlled by the control unit 11.

[0043] Piping 25 is connected to allow fluid CA to flow between interface 36a and pump 24.

[0044] Tank 26 is a pressure vessel for storing fluid CA.

[0045] Piping 27 is connected to allow fluid CA to flow between tank section 26 and pump section 24.

[0046] It should be noted that when the fluid CA is air, the fluid control unit 20 may not have a tank 26 and piping 27. In this case, the pump unit 24 can cause the air inside the bag 40 to flow out towards the outside of the clamp 30. In this case, the pump unit 24 can cause air outside the clamp 30 to flow into the bag 40.

[0047] <Bag 40> As previously described, the bag body 40 is formed into a narrowed, round-bottomed container shape by being supported by a cover 34 disposed on the support member 13. The bag body 40 has a main body portion 42 and a pressure-sensitive portion 50.

[0048] like Figure 1 As shown, the main body 42 is a hollow bag-shaped structure with a narrowed, round-bottomed container form, supported by the cover 34. The cross-sectional shape of the main body 42 is approximately U-shaped, narrowing at the opening side. In the following description, the axial direction of the main body 42, which forms the narrowed, round-bottomed container shape, will be referred to as the length direction of the bag body 40.

[0049] The main body 42 is formed of a thin-walled, film-like elastomer. The elastomer preferably includes, for example, EPDM (ethylene propylene diene monomer rubber), acrylic rubber (ACM), nitrile rubber (NBR), fluororubber (FKM), neoprene rubber, silicone rubber, or polyurethane rubber. The elastomer may also be a piezoelectric rubber. Details regarding piezoelectric rubber will be described later.

[0050] The main body 42 has an opening 44, a receiving part 46, and a front end 47.

[0051] The opening 44 is a narrowed, round-bottomed container-shaped opening at the main body 42, which is bag-shaped. The opening 44 includes the narrowed portion that forms the narrowed, round-bottomed container-shaped main body 42.

[0052] In the main body 42, which forms a narrow, round-bottomed container shape, the receiving portion 46 is located further down than the opening 44. The receiving portion 46 is connected to the opening 44. The receiving portion 46 is generally spherical. The receiving portion 46 is capable of receiving the mixture CM, described later, inside.

[0053] The front end 47 is the end of the receiving portion 46 on the side opposite to the opening portion 44. When the article MO is held with the clamp 30 of the embodiment, the distance between the front end 47 and the article MO is the closest compared to other parts of the main body portion 42.

[0054] When the hybrid CM is in a fluid-like state, the main body 42 (especially the receiving part 46) can elastically deform its surface shape to match the shape (surface shape) of the article MO upon contact with it (see reference). Figure 6 At this point, the bag 40 is in a sealed state relative to the article MO. Here, a fluid-like state refers to a state in which the bag 40, which contains the mixture CM, exhibits a fluid-like flow behavior within the bag 40. On the other hand, a solid-like state refers to a state in which the bag 40 exhibits a non-flow behavior within the bag 40.

[0055] The pressure-sensing unit 50 senses the contact pressure accompanying the contact between the main body 42 and the article MO and outputs a voltage to the detection unit 14. That is, the pressure-sensing unit 50 exhibits a piezoelectric effect. By having the pressure-sensing unit 50, the bag body 40 is able to sense the contact pressure accompanying contact with the article MO and output a voltage toward the detection unit 14. The pressure-sensing unit 50 does not impede the elastic deformation of the main body 42.

[0056] The pressure-sensitive part 50 is, for example, the main body 42 formed of piezoelectric rubber. Piezoelectric rubber is an elastomer that exhibits the piezoelectric effect. Piezoelectric rubber contains a piezoelectric material and a rubber substrate.

[0057] Piezoelectric materials are particles that exhibit the piezoelectric effect. Preferred piezoelectric materials include, for example, lead zirconate titanate, barium titanate, lithium niobate, lead titanate, lead metaniobate, polyvinylidene fluoride, or crystal.

[0058] The rubber substrate is the elastomer that retains the piezoelectric material. Preferably, the rubber substrate includes, for example, nitrile rubber, fluororubber, neoprene rubber, silicone rubber, or polyurethane rubber.

[0059] Piezoelectric rubber can be formed by methods described, for example, those specified in Japanese Patent No. 5046367, Japanese Patent Application Publication No. 60-120579, or Japanese Patent Application Publication No. 54-157297.

[0060] When the pressure-sensitive part 50 is a main body 42 formed of piezoelectric rubber, such as Figure 1 As shown, the main body 42 has a terminal portion 50a. The terminal portion 50a outputs a voltage generated based on the piezoelectric effect of the main body 42 formed of piezoelectric rubber. Figure 1 As shown, terminal 50a is connected to detection unit 14. In this case, as... Figure 2 As shown, the bag body 40 is connected to the detection unit 14 via the terminal part 50a.

[0061] like Figure 1 As shown, the terminal portion 50a in the embodiment is housed within a box-shaped base 32. The terminal portion 50a disclosed herein may also be disposed on the outer surface of a portion of the main body 42 that does not contact the article MO.

[0062] It should be noted that the pressure-sensitive part 50 can also be a piezoelectric film 52. The piezoelectric film 52 is a film that exhibits a piezoelectric effect. The piezoelectric film 52 is flexible. The piezoelectric film 52 preferably contains, for example, vinylidene fluoride, tetrafluoroethylene, trifluoroethylene, polyamino acid materials, or cellulose derivatives.

[0063] The piezoelectric film 52 can also be formed in a layered form by clamping a flexible sheet. The piezoelectric film 52 clamped by the sheet can be formed by, for example, the methods described in Japanese Patent Application Publication No. 2011-222679, Japanese Patent Application Publication No. 2020-119995, or International Publication No. 2022 / 091829.

[0064] like Figure 3 As shown, the piezoelectric film 52 is configured to cover the outer surface of the main body 42. The piezoelectric film 52 is firmly attached to the main body 42 by, for example, an adhesive or tape. Figure 3 In order to clearly show the piezoelectric film 52, the piezoelectric film 52 is shown in the figure with a gap between it and the main body 42.

[0065] The piezoelectric membrane 52 is elastically deformable along the surface shape of the main body 42. When the bag 40 comes into contact with the article MO, the main body 42 elastically deforms through the contact of the piezoelectric membrane 52 with the article MO. At this time, the piezoelectric membrane 52 and the main body 42 deform elastically together.

[0066] The piezoelectric film 52 has a terminal portion 52a. The terminal portion 52a outputs a voltage generated based on the piezoelectric effect of the piezoelectric film 52. Figure 3 As shown, terminal 52a is connected to detection unit 14. In this case, as... Figure 2 As shown, the bag body 40 is connected to the detection unit 14 via the terminal part 52a.

[0067] like Figure 3 As shown, in this embodiment, the terminal portion 52a is housed within a box-shaped base 32. The terminal portion 52a may also be disposed on the outer surface of a portion of the bag body 40 that does not contact the article MO.

[0068] It should be noted that the pressure-sensing part 50 can also be a pressure sensor 53. The pressure sensor 53 is a strip that exhibits the piezoelectric effect. The pressure sensor 53 is flexible. Figure 4 As shown, the pressure sensor 53 is disposed along the outer surface of the main body 42. The pressure sensor 53 has a strip portion 53c, an element portion 53b, and a terminal portion 53a.

[0069] The tape portion 53c is arranged along the main body portion 42 from the front end portion 47 to the opening portion 44. The tape portion 53c is flexible. The tape portion 53c has a guide portion and a cover portion (not shown).

[0070] The conductor extends along the length of the strip 53c. The conductor enables energization between the two ends of the strip 53c.

[0071] The cover protects the surface of the conductor section.

[0072] The strip 53c can also be a layered structure in which the conductor is held in place by the covering part.

[0073] The element portion 53b is a piezoelectric element exhibiting the piezoelectric effect. The element portion 53b is at least configured to contact the article MO when the gripper 30 holds the article MO. In this embodiment, the element portion 53b is provided at the end on the front end portion 47 side of the belt portion 53c. Preferably, the element portion 53b is protected by the cover portion 53e. The pressure sensor 53 according to this disclosure may also have multiple element portions 53b in the length direction of the belt portion 53c, with the multiple element portions 53b spaced apart at predetermined intervals in each portion of the wire portion 53d.

[0074] like Figure 4 As shown, the component portion 53b can also be configured to overlap with the front end portion 47 of the main body portion 42. Alternatively, the component portion 53b can be configured away from the front end portion 47.

[0075] Terminal portion 53a outputs a voltage generated based on the piezoelectric effect of element portion 53b. In this embodiment, element portion 53b is provided at the end of the strip portion 53c on the opening 44 side. Figure 4 As shown, terminal 53a is connected to detection unit 14. In this case, as... Figure 2 As shown, the bag body 40 is connected to the detection unit 14 via the terminal part 53a.

[0076] like Figure 4 As shown, in this embodiment, the terminal portion 53a is housed within a box-shaped base 32. The terminal portion 53a may also be disposed on the outer surface of a portion of the bag body 40 that does not contact the article MO.

[0077] Figure 4 The bag body 40 shown has a pressure sensor 53. When the pressure sensing part 50 is a pressure sensor 53, the bag body 40 may also have multiple pressure sensors 53. In this case, the multiple pressure sensors 53 are centered on the front end 47 of the main body 42, and extend radially in various directions toward the opening 44 in a manner that runs along the outer surface of the main body 42.

[0078] like Figure 1 , Figure 3 , Figure 4 As shown, the mixture CM is contained within the receiving portion 46 of the bag body 40. The mixture CM contains at least particles CP. The mixture CM may also contain fluid CA.

[0079] The particle size of CP is preferably 0.1 mm to 4 mm. For example, CP can be coffee powder formed by grinding coffee beans. CP can also be rice grains, glass beads, large sawdust, or diatomaceous earth.

[0080] Fluid CA can be a gas such as air. Fluid CA can also be a liquid such as water.

[0081] The mixture CM contained in the bag 40 can undergo a blocked phase transition (blocked phase transition) between a fluid-like state and a solid-like state by controlling the amount of fluid CA based on the fluid control unit 20. That is, the mixture CM contained in the bag 40 can undergo a blocked phase transition (blocked phase transition) between a fluid-like state and a solid-like state by controlling the pressure of the fluid CA inside the bag 40 based on the fluid control unit 20.

[0082] Specifically, a fluid-like mixture CM is contained within a bag 40, comprising particles CP and fluid CA. At this point, the particles CP form gaps between themselves. The fluid CA fills these gaps. When an external force is applied to the bag 40, the mixture CM flows in accordance with the deformation of the bag 40 caused by the applied force. That is, when the mixture CM is in a fluid-like state, the bag 40 becomes a state in which it can be softly deformed relative to the applied external force. This state of the bag 40 is referred to as the softened state.

[0083] For a bag 40 containing a mixture CM comprising particles CP and fluid CA, the fluid control unit 20 is operated to allow the fluid CA to flow out of the bag 40. This causes the particles CP to become tightly packed together. At this point, the gaps formed in the fluid-like state disappear. The mixture CM now consists only of particles CP. The mixture CM then transitions from a fluid-like state to a solid-like state. In this disclosure, "transition" refers to a "blocking phase change." That is, when the pressure inside the bag 40 containing the mixture CM containing particles CP and fluid CA is reduced by the fluid control unit 20, the mixture CM transitions from a fluid-like state to a solid-like state.

[0084] At this point, when an external force is applied to the bag 40, the near-solid hybrid CM functions in a way that makes the bag 40 difficult to deform. That is, when the contained hybrid CM is in a near-solid state, the bag 40 becomes hardened through the hybrid CM. This state of the bag 40 is referred to as the hardened state.

[0085] When the pressure inside the bag 40 containing the mixture CM containing particles CP and fluid CA is reduced by the fluid control unit 20, the bag 40 changes from a softened state to a hardened state.

[0086] When the fluid control unit 20 is operated to allow fluid CA to flow into the bag 40 containing a mixture CM in a near-solid state, the mixture CM becomes a state containing fluid CA, changing from a near-solid state to a near-fluid state. That is, when the pressure inside the bag 40 containing the mixture CM composed solely of particles CP is increased by the fluid control unit 20, the mixture CM changes from a near-solid state to a near-fluid state. When the pressure inside the bag 40 containing the mixture CM composed solely of particles CP is increased by the fluid control unit 20, the bag 40 changes from a hardened state to a softened state.

[0087] like Figure 2 As shown, the control unit 11 is electrically connected to the drive unit assembly including the drive unit 12, the detection unit 14, the notification unit 15, and the gripper 30. As described above, the control unit 11 controls each part of the gripping device 10. The control unit 11 includes a CPU (Central Processing Unit), a ROM (Read On Memory), RAM (Random Access Memory), and an interface. The ROM stores the program executed by the CPU. The RAM stores parameters used in the program executed by the CPU. The interface communicates with devices electrically connected to the control unit 11.

[0088] The control unit 11 includes a storage unit 11a. The storage unit 11a is a storage device such as an HDD or SSD. The storage unit 11a is capable of storing information related to the judgment unit 11b. The information related to the judgment unit 11b includes a reference value VB and a predetermined threshold VC. The threshold VC is preset by an operator (not shown) before the gripping device 10 is operated. The information related to the judgment unit 11b includes information sent to the notification unit 15 based on the judgment result of the judgment unit 54b (described later).

[0089] The control unit 11 functions as the judgment unit 11b through a program executed by the CPU. The judgment unit 11b determines the holding state of the bag body 40. The judgment unit 11b sends the judgment result of the holding state of the bag body 40 to the notification unit 15.

[0090] Details regarding the operation of the control unit 11 will be explained together with the operation of the gripping device 10 and the method for determining the gripping state, which will be shown next.

[0091] <Methods for determining the state of control> Here, use Figures 5-9 This describes the operation of the gripping device 10 and the method for determining the gripping state when the gripper 30 holds an item MO placed on the workbench TA and moves it from the workbench TA to another workbench. The other workbench is placed in a preset position.

[0092] First, such as Figure 5 As shown, the gripper 30 is positioned vertically higher than the item MO on the workbench TA. At this time, the bag 40 contains a mixture CM containing particles CP and fluid CA. The mixture CM is in a fluid-like state. The pressure P within the bag 40 is PB.

[0093] Next, as Figure 6 As shown, the control unit 11 controls the drive unit assembly to move the gripper 30 vertically downwards, so that the item MO is brought into contact with the bag body 40. At this time, the bag body 40 elastically deforms to achieve a tight fit that matches the shape of the item MO. Figure 9 (Step S30). At this time, the pressure sensing unit 50 is not in contact with the worktable TA. That is, the bag body 40 is preferably not in contact with the worktable TA. At this time, the bag body 40 outputs voltage V to the detection unit 14 through the pressure sensing unit 50 as it comes into contact with the article MO. The value of voltage V detected by the detection unit 14 is sent to the control unit 11.

[0094] Next, the control unit 11 controls the fluid control unit 20 to cause the fluid CA to flow out from the sealed bag 40. That is, as... Figure 9As shown, the control unit 11 maintains the sealed state of the bag body 40 and controls the fluid control unit 20 to depressurize the mixture CM inside the bag body 40 (step S40). At this time, the pressure P inside the bag body 40 is PV. At this time, the mixture CM inside the bag body 40 changes from a fluid-like state to a solid-like state. At this time, the bag body 40 is in a movable holding state, such as holding and handling an item MO. At this time, the voltage V output from the bag body 40 to the detection unit 14 is V1. The control unit 11 stores the value of voltage V1 sent from the detection unit 14 through step S40 as a reference value VB in the storage unit 11a (step S42).

[0095] Next, as Figure 7 As shown, the control unit 11 controls the drive unit assembly to move the gripper 30 holding the item MO vertically upward, lifting the item MO from the worktable TA. Then, the control unit 11 further controls the drive unit assembly to move the gripper 30 holding the item MO to a preset position. That is, while holding the item MO, the control unit 11 moves the bag body 40 from the worktable TA to the preset position (step S50).

[0096] During the movement of the bag 40 holding the item MO from the workbench TA to a preset position, the determination unit 11b determines the holding state of the bag 40 based on the value of the voltage V output from the bag 40 and the reference value VB stored in the storage unit 11a. Specifically, the determination unit 11b confirms whether the difference between the value of the voltage V output from the bag 40 and the reference value VB exceeds the threshold value VC stored in the storage unit 11a (step S52).

[0097] like Figure 7 As shown, during the movement of the item MO based on the gripping device 10, when the gripper 30 is holding the item MO, the bag body 40 outputs a voltage V that is approximately the same as the voltage V1 in step S40. At this time, the value of the voltage V output from the bag body 40 becomes a value V2 (≈V1) with a difference from the voltage V1 due to vibrations caused by the movement of the drive assembly used to move the item MO. The difference between the value of the voltage V2 output from the bag body 40 and the reference value VB is smaller than the threshold value VC ((|V2-VB|≤VC). At this time, in step S52, the determination unit 11b determines that the gripper 30 is maintaining the gripping state and is holding the item MO.

[0098] Subsequently, the control unit 11 determines whether the bag 40 has moved to a preset position based on the state of the drive unit assembly (step S54). If the bag 40 has not moved to the preset position, the process returns to step S52. Steps S52 and S54 are repeated at preset time intervals until the bag 40 moves to the preset position.

[0099] When the bag 40 moves to a preset position, the control unit 11 further controls the drive unit assembly to move the gripper 30 closer to another worktable positioned at the preset position, thus placing the held item MO onto it. Then, the control unit 11 controls the fluid control unit 20 to allow fluid CA to flow into the bag 40. That is, the control unit 11 controls the fluid control unit 20 to pressurize the mixture CM inside the bag 40 (step S70). At this time, the mixture CM inside the bag 40 changes from a near-solid state to a near-fluid state. At this time, the gripping state of the item MO based on the bag 40 is released. Thus, the item MO is released from the gripper 30.

[0100] Subsequently, the control unit 11 controls the drive unit assembly to move the bag body 40 away from the item MO (step S72).

[0101] On the other hand, it is explained that during the movement of the item MO based on the holding device 10 in step S50, a malfunction such as the item MO falling off the bag body 40 occurred. Figure 8 As shown, when the gripper 30 is not holding the item MO, the bag body 40 outputs voltage V3. At this time, the pressure sensing part 50 of the bag body 40 is not in contact with the item MO, so the voltage V3 output from the bag body 40 becomes a different value from the voltage V1 output when it is held. At this time, the difference between the value of the voltage V3 output from the bag body 40 and the reference value VB is greater than the threshold VC ((|V3-VB|>VC). At this time, the determination unit 11b determines in step S52 that the gripper 30 is in a state of not holding the item MO (step S60).

[0102] In this way, the control unit 11 determines the holding state of the bag 40 by confirming whether the value of the voltage V output from the hardened bag 40 exceeds the reference value VB by checking whether it exceeds the specified threshold VC.

[0103] Subsequently, in response to the occurrence of a malfunction, the control unit 11 controls the operation of each part of the gripping device 10 (step S62). Specifically, the control unit 11 controls the notification unit 15 to issue an alarm indicating that a malfunction has occurred. In addition, the control unit 11 controls the drive assembly to stop the movement of the gripper 30 toward other worktables.

[0104] It should be noted that during the movement of the item MO based on the gripping device 10 in step S50, when the bag body 40 holding the item MO collides with other components due to some malfunction, the bag body 40 outputs voltage V4. At this time, the voltage V4 output from the bag body 40 becomes a different value from the voltage V1 output when it is only in contact with the item MO. At this time, the difference between the value of the voltage V4 output from the bag body 40 and the reference value VB is also greater than the threshold VC ((|V4-VB|>VC). At this time, the determination unit 11b determines in step S52 that the gripper 30 in the gripping state has malfunctioned. Thereafter, similar to step S62, the control unit 11 controls the operation of each part of the gripping device 10 in response to the occurrence of the malfunction.

[0105] (Function and effect) Next, the function and effect of the holding device 10 will be explained.

[0106] The bag body 40 of the gripping device 10, having a pressure-sensitive part 50, can elastically deform to match the shape of the item MO and sense the contact pressure accompanying contact with the item MO, outputting a voltage to the detection part 14. Unlike mechanical devices such as buttons, the pressure-sensitive part 50 does not obstruct the elastic deformation of the main body 42. Therefore, according to the gripping device 10, the gripping state of the item MO can be determined with a simple configuration in a gripping device that grips an item using a blocking phase change.

[0107] The gripping state determination method based on the control unit 11 determines the gripping state of the bag 40 by confirming whether the value of the voltage V output from the hardened bag 40 exceeds a predetermined threshold VC. Therefore, according to the gripping state determination method based on the gripping device 10, the gripping state of the article MO based on the bag 40 utilizing the blocking phase change can be determined based on the voltage V output from the bag 40.

[0108] It should be noted that, as one method for determining the gripping state of the article MO based on the gripper 30, there is a method that detects the weight change of the gripper 30 accompanying the gripping of the article MO by using a load cell provided on the base 32 or the support member 13. When the posture of the gripper 30 holding the article MO changes in three dimensions, the relative load of the article MO with respect to the weight of the gripper 30 and the support member 13 changes in the direction corresponding to the posture of the gripper 30. Therefore, when using a load cell to determine the gripping state of the gripper 30 during the three-dimensional change in posture of the gripper 30 holding the article MO, multiple load cells need to be provided on the gripper 30 or the support member 13. On the other hand, the gripping state determination method of the embodiment determines the gripping state of the article MO based on the voltage V output from the pressure sensing unit 50 of the bag body 40. Therefore, in the determination system using the determination method of the embodiment, it is not necessary to arrange multiple pressure sensing units 50 in a manner corresponding to the three-dimensional change in posture of the gripper 30.

[0109] Furthermore, as one method for determining the gripping state of the item MO based on the gripper 30, there are methods that use optical devices such as cameras or optical sensors to optically or visually determine the state of the gripper 30. However, the configuration of a determination system utilizing methods that use optical devices to determine the state of the gripper 30 becomes complex. On the other hand, the gripping state determination method of the embodiment determines the gripping state of the item MO based on the gripper 30 based on the voltage V output from the bag body 40. Therefore, the configuration of a determination system utilizing the determination method of the embodiment becomes simple.

[0110] Therefore, the configuration of the system for determining the gripping state of an item MO based on the gripper 30 can be simplified by using the method for determining the gripping state of the implementation method.

[0111] As described above, an embodiment of the present invention has been illustrated, but the present invention is not limited to the above embodiment. Various modifications, alterations, and improvements can be made within the scope of the technical concept of the present invention.

[0112] The piezoelectric film 55 and the pressure sensor 53 are disposed along the outer surface of the main body 42. However, the piezoelectric film 52 and the pressure sensor 53 disclosed herein may also be disposed inside the film of the main body 42, which is a film-like structure. In this case, the main body 42 may also be integrally formed with the piezoelectric film 52 or the pressure sensor 53 as a substrate.

Claims

1. A gripping device capable of gripping an article, said gripping device comprising: Drive unit; A support member that can be actuated by the drive unit; The detection unit detects voltage; The bag body is disposed on the support member and is formed of an elastomer, capable of elastically deforming to match the shape of the article, and the bag body is capable of sensing the contact pressure accompanying contact with the article and outputting voltage toward the detection unit; A mixture contained within the bag and consisting of particles and fluid; and The pressure adjustment unit adjusts the pressure of the fluid contained in the bag body while maintaining the shape of the bag body.

2. The gripping device according to claim 1, wherein, It also has: Control Department; Storage Department; and Judgment Department; The control unit controls the drive unit, thereby causing the bag to elastically deform in a tight fit that matches the shape of the item by contacting it, and outputting voltage from the bag. The control unit controls the pressure adjustment unit, thereby maintaining the airtight state of the bag while depressurizing the mixture to block the phase change, thus causing the bag to transition from a softened state to a hardened state and hold the article. The storage unit stores the voltage output from the bag body as a reference value when the bag body transitions from a softened state to a hardened state. The judgment unit determines the holding state of the bag by confirming whether the difference between the voltage value output from the hardened bag and the reference value exceeds a predetermined threshold.

3. The gripping device according to claim 1 or 2, wherein, The bag body is formed of piezoelectric rubber.

4. The gripping device according to claim 1 or 2, wherein, The bag body has: The main body portion, said main body portion being formed of an elastomer; and A piezoelectric film is disposed on the outer surface of the main body.

5. The gripping device according to claim 1 or 2, wherein, The bag body has: The main body portion, said main body portion being formed of an elastomer; and A strip-shaped pressure sensor is disposed along the outer surface of the main body and is elastically deformable along the surface shape of the main body.

6. A method for determining a holding state, wherein, By bringing a bag containing a mixture of particles and fluid, and containing a predetermined amount of the fluid, into contact with the article, the bag elastically deforms in a sealed state that matches the shape of the article, and outputs voltage from the bag. By maintaining the airtight state of the bag while depressurizing the mixture to block the phase transition, the bag transitions from a softened state to a hardened state, thereby holding the article. The voltage value output from the bag body when the bag body transitions from a softened state to a hardened state is stored as a reference value. The holding state of the bag is determined by confirming whether the difference between the voltage value output from the hardened bag and the reference value exceeds a predetermined threshold.

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