Gripping device and method for gripping article

Abstract

The present invention improves gripping performance of a gripping device using jamming transition. Provided is a gripping device 10 capable of gripping an article MO, the gripping device comprising: a drive part 12; a support member 13 that can be operated by means of the drive part 12; a bag body 40 that is provided to the support member 13 and can be elastically deformed in accordance with the shape of the article MO, the bag body 40 including a first film body 42 that is formed so as to extend along an axis XC, a second film body 44 that is provided inside the first film body 42, a first accommodation part 43 that is defined between the first film body 42 and the second film body 44 and is capable of accommodating a mixture CM composed of granules CP and a first fluid CA1, and a second accommodation part 45 that is defined inside the second film body 44 and is capable of accommodating a second fluid CA2; and a first pressure adjustment part 20 that adjusts the pressure of the first fluid CA1 accommodated in the first accommodation part 43.

Description

Gripping Device and Method for Gripping an Article

[0001] The present invention relates to a gripping device and a method for gripping an article.

[0002] As described in Japanese Patent Translation No. 2013-523478 (hereinafter referred to as Patent Document 1), a gripping device having a gripper that utilizes jamming transition is known. The device described in Patent Document 1 is a passive gripping and releasing device, and includes a deformable membrane having an opening fluidly connected to a source of fluid inlet and outlet in a drainable sealed relationship, at least one port arranged in fluid connection with the opening of the membrane and providing the source of the fluid inlet and outlet, and granular material arranged in the membrane.

[0003] A gripper that utilizes jamming transition presses an article to be gripped against the surface of a bag body (corresponding to the membrane in Patent Document 1) that houses a fluid-like mixture (corresponding to the granular material in Patent Document 1), so that it is in an elastically deformed state conforming to the outer shape of the article. Then, in the state where the article is embedded and elastically deformed, by transferring the mixture in the bag body from a fluid-like state to a solid-like state, the gripper becomes a gripping state in which it can move while gripping the article. Such a gripper using jamming transition can be deformed into a shape capable of gripping various articles having various outer shapes with a certain type of bag body as long as the article can be embedded in the bag body and elastically deformed.

[0004] However, when the mixture is housed in the entire internal space of the bag body, when the gripper embeds the article in the bag body, the mixture is compressed according to the degree of deformation of the bag body, making it difficult for the mixture to flow inside the bag body. In this case, it becomes difficult for the bag body to elastically deform to conform to the outer shape of the article. Therefore, it becomes difficult for the bag body to deform into a shape capable of gripping the article. Further, when the size of the article to be gripped is large, as the article embeds deeper into the bag body, the mixture becomes even more difficult to flow, so it becomes even more difficult for the bag body to deform into a shape capable of gripping the article. Further, when the bag body that has become difficult to deform as the article embeds is further pressed against the article, there is a risk of damaging the article.

[0005] This disclosure aims to improve the gripping performance of a gripping device that utilizes jamming transition. Furthermore, this disclosure aims to increase the contact pressure between an article and a bag when gripping an article with a bag.

[0006] Aspects of the present disclosure are gripping devices capable of gripping articles, comprising: a drive unit; a support member operable by the drive unit; a bag provided on the support member and elastically deformable to conform to the shape of the article, comprising: a first membrane body formed to extend along an axis, having a first opening edge provided at an axial end and a first tip provided at an end opposite to the first opening edge; a second membrane body provided inside the first membrane body; a first containment section defined between the first membrane body and the second membrane body and capable of containing a mixture of particles and a first fluid; a second containment section defined inside the second membrane body and capable of containing a second fluid; and a first pressure adjusting unit for adjusting the pressure of the first fluid contained in the first containment section.

[0007] Another aspect of the present disclosure is a method for gripping an article using a bag that is elastically deformable to conform to the shape of an article upon contact with the article, the bag comprising: a first membrane formed to extend along an axis; a second membrane provided inside the first membrane; a first containment section defined between the first membrane and the second membrane, capable of containing a mixture of granules and a first fluid; and a second containment section defined inside the second membrane, capable of containing a second fluid. The method for gripping an article involves depressurizing the first containment section of the bag, which has elastically deformed upon contact with the article, and then depressurizing the second containment section after depressurizing the first containment section.

[0008] The gripping device of this disclosure makes it possible to improve the gripping performance of a gripping device that utilizes jamming transition.

[0009] According to the method for gripping articles described herein, the article can be gripped more easily by increasing the contact pressure between the article and the bag when gripping the article with the bag.

[0010] This is a schematic cross-sectional view of a gripping device according to an embodiment. This is a block diagram of a gripping device according to an embodiment. This is a perspective view of a gripper according to an embodiment. This is a schematic cross-sectional view of a gripping device according to a modified example. This is a schematic cross-sectional view of a gripping device according to a modified example. This is a flowchart showing the operation of gripping an article with the gripping device according to an embodiment. This is a schematic diagram showing the state before the gripping device according to an embodiment grips an article. This is a schematic diagram showing the state in which and has been released from the base. This is a schematic diagram showing the state when the gripping device according to an embodiment releases the gripped article. This is a schematic cross-sectional view of a gripping device according to a comparative embodiment.

[0011] The embodiments relating to this disclosure will be described below with reference to the drawings. The scale of the drawings is not necessarily accurate, and some features may be exaggerated or omitted. In the following description, the vertical direction (up and down direction) is referred to as the X direction. The vertically upward direction is referred to as the +X direction, and the vertically downward direction is referred to as the -X direction.

[0012] The gripping device 10 according to this disclosure is a multi-joint robot capable of handling an article MO placed on a base TA1 and moving it to a destination base (not shown), as shown in Figure 1. The gripping device 10 includes a drive unit 12, a support member 13, a gripper 30, a detection unit 14, and a control unit 11, as shown in Figure 1. The gripping device 10 further includes a notification unit 15, as shown in Figure 2. The drive unit 12 of the embodiment includes a motor and a gearbox (not shown). The drive unit 12 according to this disclosure may include a linear actuator. The operation of the motor of the drive unit 12 is controlled by the control unit 11. The support member 13 is columnar and extends 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 on the opposite side from the first end 13a. The support member 13 is operable by the drive unit 12. In the gripping device 10 of this embodiment, the drive unit 12 is further connected to other support members and other drive units (not shown).

[0013] The gripper 30 is connected to the second end 13b, as shown in Figure 1. The gripper 30 is capable of gripping the article MO. Details of the gripper 30 will be described later. The detection unit 14 detects the voltage output from the gripper 30. The detection unit 14 can transmit the numerical value of the detected voltage to the control unit 11. The detection unit 14 may also detect and transmit current instead of voltage. The notification unit 15 notifies the status of the gripping device 10. The notification unit 15 is, 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. The control unit 11 controls each part of the gripping device 10. Specifically, as shown in Figure 2, the control unit 11 is electrically connected to the drive unit group, the notification unit 15, and the gripper 30, and controls the operation of each. The drive unit group has a plurality of drive units, including the drive unit 12. The gripping device 10 can be operated to bring the gripper 30 closer to the item MO by controlling the operation of the drive unit group with the control unit 11. Details of the control unit 11 will be described later.

[0014] <Gripper 30> As shown in Figure 1, the gripper 30 includes a base 32, a cover 34, a bag 40, a mixed body CM, a plug 36, a first fluid control unit 20, and a second fluid control unit 25.

[0015] 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 each part of the gripper 30. The base 32 is capable of housing each part of the gripper 30 inside. In this embodiment, the base 32 can accommodate the terminal portion 52, the port portions 37a and 38a, and the pipes 22 and 27, which will be described later.

[0016] The cover 34 is provided on one surface of the base 32 that faces a different direction from the support member 13. In this embodiment, the cover 34 is provided on one surface of the base 32 that faces away from the second end 13b of the support member 13. The cover 34 is bowl-shaped and opens away from the base 32. The cover 34 has a hole 35. The hole 35 penetrates the cover 34 along its central axis. The hole 35 can support the outermost surface of the mouth 41a of the bag body 40, which will be described later. The cover 34 exposes the first tip 42b of the bag body 40 through the opening of the bowl-shaped cover 34. At this time, the bag body 40 has an outer shape like a round-bottomed container (see Figure 1). The cover 34 protects the area around the mouth 41a of the bag body 40.

[0017] <Bag 40> The bag 40 is bottomed and hollow. The opening of the container-shaped bag 40 is called the mouth portion 41a. The outermost surface of the mouth portion 41a is supported by the cover 34. The bag 40 has a main body portion 41 and a pressure-sensitive portion 50.

[0018] The main body portion 41 has a round-bottom container-like outer shape, as shown in Figures 1 and 3. In the following description, the axial direction of the main body portion 41, which forms a round-bottom container shape, is referred to as the longitudinal direction of the bag body 40. The main body portion 41 is made of elastomer. The elastomer preferably includes, for example, EPDM (ethylene propylene diene rubber), acrylic rubber (ACM), nitrile rubber (NBR), fluororubber (FKM), chloroprene rubber, silicone rubber, or urethane rubber. The elastomer may also be piezoelectric rubber. Piezoelectric rubber will be described in detail later. The main body portion 41 has a first membrane 42, a second membrane 44, and a plurality of rib portions 46. The main body portion 41 further has a first housing portion 43 and a second housing portion 45.

[0019] The first membrane 42 is a thin-walled, round-bottomed container. The cross-section of the first membrane 42 is U-shaped, as shown in Figure 1. The first membrane 42 defines the outer shape of the main body 41. The first membrane 42 has a first body and a first bottom. The first membrane 42 further has a first opening edge 42a and a first tip 42b. The first body is a hollow cylindrical shape that extends uniformly along the longitudinal direction of the bag 40 from the base 32 toward the cover 34. The first bottom is hemispherical and is provided to close the end of the first body opposite to the base 32. The first bottom is the round bottom of the bag 40, which is a round-bottomed container. The first opening edge 42a is provided at the end of the first body on the base 32 side. In other words, the first opening edge 42a is provided at the end of the first membrane body 42 on the base 32 side. The first opening edge 42a defines the opening of the round-bottomed container-shaped first membrane body 42. The first opening edge 42a is part of the mouth portion 41a. The first tip portion 42b is the end of the first bottom portion opposite to the first body portion. In other words, the first tip portion 42b is provided at the end of the first membrane body 42 opposite to the first opening edge 42a.

[0020] The second membrane 44 is a thin-walled, round-bottomed container-shaped structure located inside the first membrane 42, which is container-shaped. The cross-section of the second membrane 44 is U-shaped, as shown in Figure 1. The second membrane 44 has a second body and a second bottom. The second membrane 44 further has a second opening edge 44a and a second tip 44b. The second body is a hollow cylindrical shape that extends uniformly along the longitudinal direction of the bag 40 from the base 32 toward the cover 34. The second bottom is a hemispherical shape that closes the end of the second body opposite to the base 32. The second opening edge 44a is located at the end of the second body on the base 32 side. That is, the second opening edge 44a is located at the end of the second membrane 44 on the base 32 side. The second opening edge 44a defines the opening of the round-bottomed container-shaped second membrane body 44. The second opening edge 44a is part of the mouth portion 41a. The second tip portion 44b is the end of the second bottom portion opposite to the second body portion. That is, the second tip portion 44b is provided at the end of the second membrane body 44 opposite to the second opening edge 44a. In this way, the main body portion 41 is a double-layered bag-like structure composed of the first membrane body 42 and the second membrane body 44.

[0021] The first housing portion 43 is a space defined between the first membrane 42 and the second membrane 44. The first housing portion 43 is formed around the axis XC. The first housing portion 43 is capable of accommodating a mixture CM containing the first fluid CA1, which will be described later. The first housing portion 43 is sealed by the first stopper 37 of the stopper portion 36, which will be described later. That is, the first housing portion 43 is further defined by the first stopper 37.

[0022] The second containment portion 45 is a space defined inside the container-shaped second membrane 44. The second containment portion 45 is formed around the axis XC. The second containment portion 45 is capable of containing the second fluid CA2. The second fluid CA2 is, for example, a gas such as air. The second fluid CA2 may also be a liquid such as water. The second containment portion 45 is sealed by the second stopper 38 of the stopper portion 36. That is, the second containment portion 45 is further defined by the second stopper 38.

[0023] As shown in Figure 3, the rib portion 46 is positioned between the first membrane 42 and the second membrane 44. The rib portion 46 is formed to conform to the inner surface of the first membrane 42 and the outer surface of the second membrane 44. The rib portion 46 is columnar in shape, curving outwards from the first opening edge 42a side of the first membrane 42 toward the first tip portion 42b side. In other words, the rib portion 46 curves outwards from the second opening edge 44a side of the second membrane 44 toward the second tip portion 44b side.

[0024] Multiple rib portions 46 are arranged in a line around the axis XC. In the bag body 40 of this embodiment, four rib portions 46 are arranged in a line around the axis XC. Each of the multiple rib portions 46 is integrally provided with the first membrane body 42 and the second membrane body 44. The multiple rib portions 46 are connected to each other at the first tip portion 42b and the second tip portion 44b. That is, the multiple rib portions 46 form a connecting portion 47 at the first tip portion 42b and the second tip portion 44b. As a result, the multiple rib portions 46 divide the first storage portion 43 into multiple storage chambers 43a. Each of the multiple storage chambers 43a is capable of accommodating the mixed material CM.

[0025] It is preferable that the multiple rib portions 46 are arranged at equal intervals from one another in the circumferential direction. In this case, the multiple rib portions 46 equally divide the first housing portion 43.

[0026] Preferably, each of the multiple rib portions 46 is integrally molded with at least one of the first membrane 42 or the second membrane 44. The multiple rib portions 46 may be integrally molded with both the first membrane 42 and the second membrane 44. Of the multiple rib portions 46, some of the rib portions 46 may be integrally molded with the first membrane 42 and the remaining rib portions 46 may be integrally molded with the second membrane 44. Note that each of the multiple rib portions 46 may be molded separately from the first membrane 42 and the second membrane 44.

[0027] The mixture CM is housed in the housing chamber 43a of the first housing section 43, as shown in Figure 1. The mixture CM contains at least granular CP. The mixture CM may also contain a first fluid CA1. The granular CP preferably has a particle size of 0.1 mm to 4 mm. The granular CP is, for example, coffee powder made by grinding coffee beans. The granular CP may also be rice grains, glass beads, sawdust, or diatomaceous earth. The first fluid CA1 is, for example, a gas such as air. The first fluid CA1 may also be a liquid such as water.

[0028] The mixed material CM contained in the first containment section 43 of the bag body 40 can undergo a pseudo-phase transition (jamming transition) between a fluid-like state and a solid-like state by controlling the amount of the first fluid CA1 by the first fluid control unit 20, which will be described later. That is, the mixed material CM contained in the main body section 41 can undergo a pseudo-phase transition (jamming transition) between a fluid-like state and a solid-like state by controlling the pressure of the first fluid CA1 in the main body section 41 by the first fluid control unit 20.

[0029] When the mixture CM is fluid-like, the main body 41 (especially the first film 42) can elastically deform its surface shape to match the outer shape (surface shape) of the article MO upon contact with the article MO (see Figure 8). At this time, the main body 41 becomes in close contact with the article MO. Here, "fluid-like" means that the mixture CM exhibits fluid-like flow behavior within the main body 41, conforming to the shape of the main body 41 that houses it. On the other hand, "solid-like" means that the mixture CM does not flow within the main body 41.

[0030] The fluid-like mixture CM is housed in the first containment section 43, containing granular particles CP and the first fluid CA1. At this time, the granular particles CP form gaps between themselves. The first fluid CA1 fills the gaps formed by the granular particles CP. When an external force is applied to the bag 40 at this time, the mixture CM flows in accordance with the deformation of the bag 40 due to the application of the external force. That is, when the mixture CM is fluid-like, the bag 40 becomes flexible and can deform in response to the applied external force. This state of the bag 40 is called the softened state.

[0031] The first fluid control unit 20 is operated on a bag 40 containing a mixture CM containing granular particles CP and a first fluid CA1 to cause the first fluid CA1 to flow out from the first containment section 43 of the bag 40. As a result, the granular particles CP become tightly packed together. At this time, the gaps that were formed when it was in a fluid state disappear. At this time, the mixture CM is composed only of granular particles CP. At this time, the mixture CM transitions from a fluid state to a solid state. In this disclosure, "transition" means "pseudo-phase transition". That is, when the pressure inside the first containment section 43 containing the mixture CM containing granular particles CP and the first fluid CA1 is reduced by the first fluid control unit 20, the mixture CM transitions from a fluid state to a solid state. When an external force is applied to the bag 40 at this time, the solid-state mixture CM acts to make the bag 40 less likely to deform. In other words, when the contained mixture CM is solid, the bag 40 becomes hardened by the mixture CM. This state of the bag 40 is called the hardened state. Thus, when the pressure inside the first containment section 43 containing the mixture CM is reduced by the first fluid control unit 20, the bag 40 transitions from a softened state to a hardened state.

[0032] When the first fluid control unit 20 is operated to allow the first fluid CA1 to flow into the first containment section 43 of the bag 40 containing the solid-like mixture CM, the mixture CM becomes a state containing the first fluid CA1 and transitions from a solid-like state to a fluid-like state. In other words, when the first fluid control unit 20 increases the pressure inside the first containment section 43 containing the mixture CM composed only of granular CP, the mixture CM transitions from a solid-like state to a fluid-like state. That is, when the first fluid control unit 20 increases the pressure inside the first containment section 43 containing the mixture CM composed only of granular CP, the bag 40 transitions from a hardened state to a softened state.

[0033] The pressure-sensitive part 50 outputs a voltage to the detection unit 14 upon contact between the main body 41 and the article MO. In other words, the pressure-sensitive part 50 exhibits a piezoelectric effect. The bag 40, by having the pressure-sensitive part 50, can output a voltage toward the detection unit 14 upon contact with the article MO. The pressure-sensitive part 50 may also output a current instead of voltage. The pressure-sensitive part 50 does not hinder the elastic deformation of the main body 41.

[0034] The pressure-sensitive part 50 is, for example, a main body part 41 formed of piezoelectric rubber. Piezoelectric rubber is an elastomer that exhibits a piezoelectric effect. Piezoelectric rubber includes a piezoelectric material and a rubber matrix. The piezoelectric material is particulate and exhibits a piezoelectric effect. The piezoelectric material preferably includes, for example, lead zirconate titanate, barium titanate, lithium niobate, lead titanate, lead metaniobate, polyvinylidene fluoride, or quartz. The rubber matrix is ​​an elastomer that holds the piezoelectric material. The rubber matrix preferably includes, for example, nitrile rubber, fluororubber, chloroprene rubber, silicone rubber, or urethane rubber. Piezoelectric rubber can be formed, for example, by the method described in Japanese Patent No. 5046367, Japanese Unexamined Patent Publication No. 60-120579, or Japanese Unexamined Patent Publication No. 54-157297.

[0035] When the pressure-sensitive portion 50 is a main body portion 41 made of piezoelectric rubber, the main body portion 41 has a terminal portion 52, as shown in Figure 1. The terminal portion 52 outputs a voltage generated by the piezoelectric effect of the main body portion 41 made of piezoelectric rubber. The terminal portion 52 is connected to the detection portion 14, as shown in Figure 1. In this case, the bag 40 is connected to the detection portion 14 through the terminal portion 52, as shown in Figure 2. The terminal portion 52 of the embodiment is housed in a box-shaped base portion 32, as shown in Figure 1. The terminal portion 52 according to this disclosure may be located on a part of the outer surface of the main body portion 41 that does not come into contact with the article MO.

[0036] When the pressure-sensitive part 50 is a main body 41 made of piezoelectric rubber, it is preferable that at least one of the first film 42, the second film 44, and the plurality of rib portions 46 is made of piezoelectric rubber. In this case, it is particularly preferable that the plurality of rib portions 46 are made of piezoelectric rubber. In this case, it is more preferable that the plurality of rib portions 46 are integrally molded with either the first film 42 or the second film 44. In this case, it is preferable that the thickness of the rib portion 46 is greater than the thickness of the first film 42. The thickness of the rib portion 46 is the length of the rib portion 46 in the thickness direction of the first film 42.

[0037] The pressure-sensitive portion 50 may be a piezoelectric film 250. The piezoelectric film 250 is a film that exhibits a piezoelectric effect. The piezoelectric film 250 is flexible. The piezoelectric film 250 preferably contains, for example, vinylidene fluoride, tetrafluoroethylene, trifluoroethylene, polyamino acid material, or cellulose derivative.

[0038] The piezoelectric film 250 may be formed in layers by sandwiching it between flexible sheet materials. The piezoelectric film 250 sandwiched between sheet materials can be formed, for example, by the method described in Japanese Patent Application Publication No. 2011-222679, Japanese Patent Application Publication No. 2020-119995, or International Publication No. 2022 / 091829.

[0039] As shown in Figure 4, the piezoelectric film 250 is positioned to cover the outer surface of the main body 41. The piezoelectric film 250 is fixed to the main body 41, for example, with an adhesive or tape. In Figure 4, the piezoelectric film 250 is shown spaced apart from the main body 41 to make it clearly visible. The piezoelectric film 250 is elastically deformable to conform to the surface shape of the main body 41. When the bag 40 comes into contact with the article MO, the main body 41 comes into contact with the article MO via the piezoelectric film 250 and elastically deforms. At this time, the piezoelectric film 250 elastically deforms together with the main body 41.

[0040] The piezoelectric film 250 has a terminal portion 252. The terminal portion 252 outputs a voltage generated by the piezoelectric effect of the piezoelectric film 250. The terminal portion 252 is connected to the detection unit 14, as shown in Figure 4. In this case, the bag 40 is connected to the detection unit 14 through the terminal portion 252, as shown in Figure 2. In this embodiment, the terminal portion 252 is housed in a box-shaped base portion 32, as shown in Figure 4. The terminal portion 252 may be located on a part of the outer surface of the bag 40 that does not come into contact with the article MO.

[0041] Incidentally, the pressure-sensitive part 50 may be a pressure-sensitive sensor 350. The pressure-sensitive sensor 350 is strip-shaped and exhibits a piezoelectric effect. The pressure-sensitive sensor 350 has flexibility. As shown in FIG. 5, the pressure-sensitive sensor 350 is arranged along the outer surface of the main body part 41. The pressure-sensitive sensor 350 has a strip part 356, an element part 354, and a terminal part 352.

[0042] The strip part 356 is arranged along the main body part 41 from the first tip part 42b to the first opening edge 42a. The strip part 356 has flexibility. The strip part 356 has a wire part (not shown) and a covering part. The wire part extends along the longitudinal direction of the strip part 356. The wire part enables electricity to flow between both ends of the strip part 356. The covering part covers and protects the surface of the wire part. The strip part 356 may be layered with the wire part sandwiched by the covering part.

[0043] The element part 354 is a piezoelectric element that exhibits a piezoelectric effect. The element part 354 is arranged at least so as to come into contact with the article MO when the gripper 30 grips the article MO. The element part 354 of the embodiment is provided at the end of the strip part 356 on the side of the first tip part 42b. The element part 354 is preferably protected by the covering part. The pressure-sensitive sensor 350 according to the present disclosure may have a plurality of element parts 354 provided at predetermined intervals for each part of the wire part in the longitudinal direction of the strip part 356. As shown in FIG. 5, the element part 354 may be arranged so as to overlap the first tip part 42b of the main body part 41. The element part 354 may be arranged at a position away from the first tip part 42b.

[0044] The terminal part 352 outputs the voltage generated by the piezoelectric effect of the element part 354. The element part 354 of the embodiment is provided at the end of the strip part 356 on the side of the first opening edge 42a. As shown in FIG. 5, the terminal part 352 is connected to the detection part 14. In this case, as shown in FIG. 2, the bag body 40 is connected to the detection part 14 through the terminal part 352. As shown in FIG. 5, the terminal part 352 of the embodiment is housed in a box-shaped base part 32. The terminal part 352 may be arranged on the outer surface of a part of the bag body 40 that does not come into contact with the article MO.

[0045] The bag body 40 shown in Figure 5 has one pressure sensor 350. If the pressure-sensitive part 50 is a pressure sensor 350, the bag body 40 may have multiple pressure sensors 350. In this case, the multiple pressure sensors 350 are arranged radially from the first tip portion 42b of the main body portion 41, in directions along the radial direction, and extend along the outer surface of the main body portion 41 toward the first opening edge 42a.

[0046] The plug portion 36 is positioned inside the opening 41a of the bag body 40 supported by the hole portion 35 so as to seal and close the opening 41a. In this embodiment, the plug portion 36 is fixed to the cover 34 or base portion 32 using a connecting member (not shown) while sealing the inside of the opening 41a. The connecting member may include, for example, a bolt and a nut. The plug portion 36 has a first plug body 37 and a second plug body 38.

[0047] The first stopper 37 is annular in shape and positioned between the first opening edge 42a and the second opening edge 44a of the bag body 40. The first stopper 37 seals the first containment section 43 of the bag body 40. The first stopper 37 further seals a plurality of containment chambers 43a individually. The first stopper 37 has a plurality of port sections 37a. Each of the plurality of port sections 37a is provided corresponding to each of the plurality of containment chambers 43a. Each of the plurality of port sections 37a is tubular in shape, allowing the first fluid CA1 to flow between each of the plurality of containment chambers 43a sealed by the first stopper 37 and the outside of the bag body 40. Each of the plurality of port sections 37a has a filter section 37b and a connecting end 37c. The filter section 37b is provided at the end of the port section 37a facing the containment chamber 43a side. The filter section 37b is capable of passing the first fluid CA1. The filter section 37b prevents the passage of granular CP. The connecting end 37c is the end of the port section 37a opposite to the filter section 37b. The connecting end 37c is housed inside the base section 32. The piping 22 of the first fluid control unit 20 is connected to the connecting end 37c.

[0048] The second plug body 38 is disc-shaped and is disposed inside the second opening edge 44a so as to seal and close the second opening edge 44a of the second membrane body 44. The second plug body 38 seals the second accommodation portion 45 of the bag body 40. The second plug body 38 has a port portion 38a. The port portion 38a is tubular and allows the second fluid CA2 to flow between the second accommodation portion 45 sealed by the second plug body 38 and the outside of the bag body 40. The port portion 38a has a connection end 38c. The connection end 38c is the end of the port portion 38a on the side far from the second accommodation portion 45. The connection end 38c is accommodated inside the base portion 32. The pipe 27 of the second fluid control portion 25 is connected to the connection end 38c.

[0049] The first fluid control portion 20 controls the amount of the first fluid CA1 accommodated in the first accommodation portion 43 through the plurality of port portions 37a. The first fluid control portion 20 adjusts the pressure of the first fluid CA1 accommodated in the first accommodation portion 43. That is, the first fluid control portion 20 adjusts the pressure inside the first accommodation portion 43. The first fluid control portion 20 is an example of the first pressure adjustment portion. The first fluid control portion 20 can make the inside of the first accommodation portion 43 into a vacuum state.

[0050] The first fluid control portion 20 includes a pump portion 21, a pipe 22, a tank portion 23, and a pipe 24. The pump portion 21 causes the first fluid CA1 to flow out or flow into the connection destinations of the pipes 22 and 24 through the pipes 22 and 24. The operation of the pump portion 21 is controlled by the control portion 11. That is, the operation of the first fluid control portion 20 is controlled by the control portion 11. The pipe 22 is connected so as to allow the first fluid CA1 to flow between the pump portion 21 and the plurality of port portions 37a. The tank portion 23 is a pressure vessel that stores the first fluid CA1. The pipe 24 is connected so as to allow the first fluid CA1 to flow between the pump portion 21 and the tank portion 23. When the first fluid CA1 is air, the first fluid control portion 20 may not have the tank portion 23 and the pipe 24. In this case, the pump portion 21 can cause the air inside the first accommodation portion 43 to flow out toward the outside of the gripper 30. In this case, the pump portion 21 can cause the air outside the gripper 30 to flow into the first accommodation portion 43.

[0051] The second fluid control unit 25 controls the amount of the second fluid CA2 contained in the second housing 45 through the port 38a. The second fluid control unit 25 adjusts the pressure of the second fluid CA2 contained in the second housing 45. That is, the second fluid control unit 25 adjusts the pressure inside the second housing 45. The second fluid control unit 25 is an example of a second pressure adjustment unit. The second fluid control unit 25 can create a vacuum inside the second housing 45.

[0052] The second fluid control unit 25 includes a pump unit 26, piping 27, a tank unit 28, and piping 29. The pump unit 26 causes the second fluid CA2 to flow out or into the connections of the pipes 27 and 29 through the pipes 27 and 29. The operation of the pump unit 26 is controlled by the control unit 11. That is, the operation of the second fluid control unit 25 is controlled by the control unit 11. Piping 27 connects the pump unit 26 and the port unit 38a so that the second fluid CA2 can flow through it. The tank unit 28 is a pressure vessel for storing the second fluid CA2. Piping 29 connects the pump unit 26 and the tank unit 28 so that the second fluid CA2 can flow through it. Note that if the second fluid CA2 is air, the second fluid control unit 25 does not need to have the tank unit 28 and piping 29. In this case, the pump unit 26 can discharge the air inside the second housing 45 toward the outside of the gripper 30. In this case, the pump unit 26 can draw in air from outside the gripper 30 toward the second housing 45.

[0053] As shown in Figure 2, the control unit 11 is electrically connected to a group of drive units including the drive unit 12, a detection unit 14, a notification unit 15, and a gripper 30. The control unit 11 controls each part of the gripping device 10 as described above. The control unit 11 has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an interface. The ROM stores the program executed by the CPU. The RAM stores parameters and the like used by the program executed by the CPU. The interface communicates with devices electrically connected to the control unit 11.

[0054] The control unit 11 functions as a determination unit 11b according to a program executed by the CPU. The determination unit 11b determines the gripping state of the bag 40. The determination unit 11b transmits the determination result of the gripping state of the bag 40 to the notification unit 15.

[0055] The control unit 11 has a storage unit 11a. The storage unit 11a is a storage device such as an HDD or SSD. The storage unit 11a can store information related to the determination unit 11b. The information related to the determination unit 11b includes a reference value VB and a predetermined threshold value VC. The threshold value VC is set in advance by an operator (not shown) before the gripping device 10 is operated. The information related to the determination unit 11b includes information transmitted to the notification unit 15 based on the determination result of the determination unit 11b, which will be described later. Details of the operation of the control unit 11 will be explained below along with the method of gripping the article MO with the gripping device 10.

[0056] <Method for gripping the item MO> Here, the operation of the gripping device 10 and the method for gripping the item MO when the item MO placed on the base TA1 is gripped by the gripper 30 and then moved from base TA1 to another base TA2 for placement will be explained using Figures 6 to 10. Base TA2 is placed in a predetermined position. Figure 6 is a flowchart showing the process of gripping the item MO with the gripping device 10.

[0057] First, as shown in Figure 7, the gripper 30 is positioned vertically above the article MO on the base TA1. At this time, the mixture CM contained in the first containment section 43 of the bag 40 is fluid. At this time, the pressure P1 in each of the multiple containment chambers 43a and the pressure P2 in the second containment section 45 are PB.

[0058] Next, the control unit 11 controls the drive unit group to move the gripper 30 vertically downward, as shown in Figure 8, so that the article MO is pressed into the bag 40. At this time, the bag 40 elastically deforms in a tight fit to match the outer shape of the article MO (step S30 in Figure 6). Specifically, the first membrane 42 elastically deforms in a tight fit to match the outer shape of the article MO. At this time, the second membrane 44 and the rib portion 46 elastically deform in accordance with the deformation of the first membrane 42. At this time, it is preferable that the bag 40 does not come into contact with the base TA1. At this time, the pressure-sensitive unit 50 does not come into contact with the base TA1. At this time, as the bag 40 comes into contact with the article MO, the pressure-sensitive unit 50 outputs a voltage V toward the detection unit 14. The value of the voltage V detected by the detection unit 14 is transmitted to the control unit 11.

[0059] Next, as shown in Figure 6, the control unit 11 controls the first fluid control unit 20 to reduce the pressure in the first containment section 43 (step S40). At this time, the first fluid CA1 flows out from each of the multiple containment chambers 43a. In other words, the control unit 11 controls the first fluid control unit 20 to cause the first fluid CA1 to flow out of the first containment section 43 while the bag 40 is in close contact with the article MO. At this time, the pressure P1 value in each of the multiple containment chambers 43a is PV1. At this time, the mixture CM inside the bag 40 transitions from a fluid state to a solid state. At this time, the bag 40 becomes a gripping state in which it can move while gripping the article MO.

[0060] Subsequently, the control unit 11 controls the second fluid control unit 25 to reduce the pressure in the second housing 45 (step S41). At this time, the second fluid CA2 flows out of the second housing 45. In this way, the control unit 11 controls the second fluid control unit 25 to reduce the pressure in the second housing 45 after the first housing 43 has been reduced in pressure by the first fluid control unit 20. At this time, the value of the pressure P2 in the second housing 45 is PV2. It is preferable that the value of the pressure PV2 is smaller than the pressure P1 (=PV1) in the first housing 43 at this time. At this time, the pressure P2 (=PV2) in the second housing 45 acts to contract the second membrane 44 more than when the value of the pressure P2 in the second housing 45 is PB (<PV2). Due to the action of the pressure P2 in the second housing 45, the pressure P1 in the first housing 43 is further reduced. At this time, the density of the granular CP in the first containment section 43 increases. As a result, the contact pressure between the first film 42 and the article MO increases.

[0061] At this time, the value of the voltage V output from the bag 40 to the detection unit 14 is V1. The control unit 11 stores the value of the voltage V1 transmitted from the detection unit 14 in step S41 as a reference value VB in the storage unit 11a (step S42).

[0062] Next, the control unit 11 controls the drive unit group to move the gripper 30, which is gripping the item MO, vertically upward, as shown in Figure 9, thereby lifting the item MO from the base TA1. The control unit 11 then further controls the drive unit group to move the gripper 30, which is gripping the item MO, to a preset position. That is, the control unit 11 moves the bag 40, which is gripping the item MO, from the base TA1 to a preset position (step S50).

[0063] During the movement period in which the bag 40, which is gripping the item MO, moves from the base TA1 to a preset position, the determination unit 11b determines the gripping state of the bag 40 based on the voltage V output from the bag 40 and the reference value VB stored in the storage unit 11a. Specifically, the determination unit 11b checks whether the difference between 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).

[0064] During the period when the gripping device 10 moves the article MO, as shown in Figure 9, when the gripper 30 is gripping the article MO, the bag 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 40 becomes a value V2 (≒V1) which is different from the voltage V1 due to vibrations etc. associated with the operation of the drive group for moving the article MO. The difference between the value of the voltage V2 output from the bag 40 and the reference value VB is smaller than the threshold value VC (│V2-VB│≦VC). At this time, the determination unit 11b determines in step S52 that the gripper 30 is maintaining the gripping state and gripping the article MO.

[0065] Subsequently, the control unit 11 determines whether the bag 40 has moved to a preset position based on the state of the drive unit group (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.

[0066] When the bag 40 moves to a preset position, the control unit 11 further controls the drive unit group, as shown in Figure 10, to bring the gripper 30 closer to the base TA2 so that the gripped article MO is placed on the base TA2. Subsequently, the control unit 11 controls the first fluid control unit 20 to pressurize the first containment section 43, as shown in Figure 6 (step S70). At this time, the first fluid CA1 flows into each of the multiple containment chambers 43a. In other words, the control unit 11 controls the first fluid control unit 20 to cause the first fluid CA1 to flow into the first containment section 43. At this time, the pressure P1 value in each of the multiple containment chambers 43a is PB. At this time, the mixture CM contained in each of the multiple containment chambers 43a transitions from a solid-like state to a fluid-like state.

[0067] Subsequently, the control unit 11 controls the second fluid control unit 25 to pressurize the second housing section 45 (step S71). At this time, the second fluid CA2 flows into the second housing section 45. In this way, the control unit 11 pressurizes the second housing section 45 by controlling the second fluid control unit 25 after the first housing section 43 has been pressurized by the first fluid control unit 20. At this time, the value of the pressure P2 in the second housing section 45 is PP. It is preferable that the value of the pressure PP is greater than the pressure P1 (= PB) in the first housing section 43 at this time. At this time, the pressure P2 (= PP) in the second housing section acts to cause the second membrane 44 to expand more than when the value of the pressure P2 in the second housing section 45 is PB (< PP). At this time, the first housing section 43 and the first membrane 42 expand in accordance with the expansion of the second membrane 44. As a result, the bag 40 applies a force to the article MO that pushes it away from the bag 40. At this time, the gripping state of the article MO by the bag 40 is released. The article MO is then separated from the gripper 30 and released. Subsequently, the control unit 11 controls the drive unit group to move the bag 40 away from the article MO (step S72).

[0068] On the other hand, the following describes what happens when a problem occurs during the movement of the article MO by the gripping device 10 in step S50, such as the article MO falling from the bag 40. When the gripper 30 is not gripping the article MO, the bag 40 outputs a voltage V3. At this time, since the pressure-sensitive part 50 of the bag 40 is not in contact with the article MO, the voltage V3 output from the bag 40 is a different value from the voltage V1 output when gripping. At this time, the difference between the value of the voltage V3 output from the bag 40 and the reference value VB is greater than the threshold value VC (│V3-VB│>VC). At this time, the determination unit 11b determines in step S52 that the gripper 30 is not gripping the article MO (step S60). In this way, the control unit 11 determines the gripping state of the bag 40 by checking whether the value of the voltage V output from the hardened bag 40 and the reference value VB exceed a predetermined threshold value VC.

[0069] Subsequently, the control unit 11 controls the operation of each part of the gripping device 10 in response to the occurrence of a problem (step S62). Specifically, the control unit 11 controls the notification unit 15 to notify an alert indicating the occurrence of a problem. The control unit 11 also controls the drive unit group to stop the movement of the gripper 30 toward the base TA2.

[0070] Furthermore, during the movement of the article MO by the gripping device 10 in step S50, if another component or the like collides with the bag body 40 gripping the article MO due to some trouble, the bag body 40 outputs a voltage V4. At this time, the voltage V4 output from the bag body 40 is a different value from the voltage V1 output when it is in contact only with the article MO while gripping. At this time, the difference between the value of the voltage V4 output from the bag body 40 and the reference value VB is greater than the threshold value VC (│V4-VB│>VC). At this time, the determination unit 11b determines in step S52 that a problem has occurred in the gripper 30 in the gripping state. Subsequently, the control unit 11 controls the operation of each part of the gripping device 10 in accordance with the occurrence of the problem, similar to step S62.

[0071] (Operation and Effects) Next, the operation and effects of the gripping device 10 will be described. The gripper 30 of the gripping device 10 has a first membrane 42 and a second membrane 44. The second membrane 44 defines a second containment section 45 for containing the second fluid CA2. The bag 40 contains the mixture CM in a first containment section 43 defined by the first membrane 42 and the second membrane 44. Therefore, the fluid-like mixture CM contained in the first containment section 43 flows easily in accordance with the deformation of the bag 40. As a result, when the bag 40 is pressed against the article MO during the operation of gripping the article MO with the gripping device 10, the bag 40 is easily elastically deformed to conform to the shape of the article MO. In other words, the bag 40 having the first membrane 42 and the second membrane 44 makes it easier to shape the article MO into a grippable form when pressed against the article MO during the operation of gripping the article MO with the gripping device 10. Therefore, the gripping device 10 can improve the gripping performance of a gripping device that grips an article MO by utilizing jamming transition.

[0072] The gripper 30 of the gripping device 10 further has a plurality of rib portions 46. As a comparative example to the gripper 30 having a plurality of rib portions 46, a gripper H30 having a bag H40 shown in Figure 11 will be described. The bag H40 does not have a plurality of rib portions 46 compared to the bag 40 of the embodiment. As a result, the bag H40 has a single housing portion H43 instead of the first housing portion 43 of the bag 40. The housing portion H43 is not divided into a plurality of housing chambers 43a. In other respects, the configuration of the gripper H30 is the same as the gripper 30 of the embodiment. The bag H40 houses the mixed material CM together in a single housing portion H43. Therefore, when jamming the mixed material CM housed in the bag H40, there is a risk that the degree of displacement of the mixed material CM will vary at each position within the housing portion H43. On the other hand, the bag body 40 of the gripper 30 has a plurality of rib portions 46, which divides the first containment section 43 into a plurality of containment chambers 43a. As a result, the first containment section 43 can contain the mixed substance CM in a state where it is distributed among the plurality of containment chambers 43a. Therefore, when the mixed substance CM contained in the bag body 40 is subjected to jamming transfer, the mixed substance CM is transferred in a state where it is distributed among the plurality of containment chambers 43a. In this case, variations in the degree of transfer of the mixed substance CM are less likely to occur among the plurality of containment chambers 43a. Thus, the gripping device 10 can suppress variations in the degree of jamming transfer of the mixed substance CM when the mixed substance CM contained in the bag body 40 is subjected to jamming transfer.

[0073] The multiple rib sections 46 equally divide the first housing section 43. In this case, the size of each of the multiple housing chambers 43a is equal to that of the others. As a result, each of the multiple housing chambers 43a can accommodate an equal amount of the mixed material CM. Therefore, the gripping device 10 can cause the mixed material CM housed in each of the housing chambers 43a to be jammed and transferred to each other to an equal degree.

[0074] The multiple rib portions 46 are integrally molded with either the first membrane 42 or the second membrane 44. Therefore, the gripping device 10 allows the bag 40, which is composed of the first membrane 42, the second membrane 44, and the multiple rib portions 46, to be easily attached to the gripping device 10.

[0075] At least one of the first membrane 42, the second membrane 44, and the multiple rib portions 46 is made of piezoelectric rubber. Therefore, the gripping device 10 can output a voltage from the bag 40 in accordance with the elastic deformation of the bag 40 due to contact with the article MO.

[0076] The bag 40 of the gripping device 10 has a pressure-sensitive section 50, which allows it to output a voltage or current towards the detection section 14 upon contact with the article MO. The gripping device 10 has a detection section 14. Therefore, the gripping device 10 can determine the gripping state of the article MO by detecting the voltage output upon contact with the article MO. In particular, when the detection section 14 detects the voltage or current output from the rib section 46 made of piezoelectric rubber, the gripping device 10 can improve the accuracy of determining the gripping state of the article MO. Specifically, the magnitude of the voltage or current output from the piezoelectric rubber is proportional to the density of the piezoelectric material contained in the piezoelectric rubber. Since the thickness of the rib section 46 is greater than the thickness of the first film 42, the rib section 46 can be molded from piezoelectric rubber with a higher density of piezoelectric material than the first film 42. In this case, the bag 40 can improve the value of the voltage or current output upon contact with the article MO. In this case, the detection sensitivity of the detection unit 14 to the voltage or current output from the bag 40 is improved, so the gripping device 10 can improve the accuracy of determining the gripping state of the article MO.

[0077] The gripper 30 of the gripping device 10 further includes a second fluid control unit 25. Therefore, the gripping device 10 can further improve the gripping performance as a gripping device that grips an article MO using jamming transition. Specifically, when the gripping device 10 grips an article MO with the bag 40, the first fluid control unit 20 depressurizes the first housing 43, and then the second fluid control unit 25 depressurizes the second housing 45. In this case, as explained in the gripping method of the article MO using the gripping device 10 described above, the gripping device 10 can increase the contact surface pressure between the first membrane 42 and the article MO when gripping the article MO with the bag 40. As a result, the gripping device 10 can increase the upper limit of the weight of the article MO that can be gripped. Therefore, the gripping method of the article MO using the gripping device 10 can improve the gripping force of the bag 40 on the article MO. In other words, the method of gripping an article MO using the gripping device 10 makes it easier to grip the article MO with a gripping device that utilizes jamming transition.

[0078] When the gripping device 10 releases the gripped article MO, it first pressurizes the first containment section 43 with the first fluid control unit 20, and then pressurizes the second containment section 45 with the second fluid control unit 25. In this case, as explained in the gripping method of the article MO using the gripping device 10 described above, the gripping device 10 applies a force to the article MO that pushes it out of the bag 40. Therefore, the gripping method of the article MO using the gripping device 10 makes it easier to separate the article MO from the bag 40 when releasing it from the bag 40. Furthermore, when the second containment section 45 is pressurized by the second fluid control unit 25, the second membrane 44 applies a force to the first membrane 42 via the mixture CM in the first containment section 43 that causes the first membrane 42 to expand. The force applied from the second membrane 44 to expand the first membrane 42 acts on the first membrane 42 to restore it to its shape before it was deformed by contact with the article MO. Therefore, the method of gripping the article MO using the gripping device 10 makes it easier to restore the shape of the bag 40, which has been deformed by gripping the article MO, to its shape before gripping the article MO.

[0079] As described above, an embodiment of the present invention has been explained as an example, but the present invention is not limited to the above-described embodiment, and various modifications, changes, and improvements are possible within the scope of the technical idea of ​​the present invention.

[0080] The piezoelectric film 250 and the pressure sensor 350 are arranged along the outer surface of the first film body 42. However, the piezoelectric film 250 and the pressure sensor 350 according to this disclosure may be provided on the inner surface of the first film body 42. In this case, the first film body 42 may be integrally molded with the piezoelectric film 250 or the pressure sensor 350, using the piezoelectric film 250 or the pressure sensor 350 as the base material.

[0081] 10 Gripping device 11 Control unit 12 Drive unit 13 Support member 14 Detection unit 20 First fluid control unit (example of first pressure adjustment unit) 25 Second fluid control unit (example of second pressure adjustment unit) 30 Gripper 32 Base 36 Plug 40 Bag 42 First membrane 42a First opening edge 42b First tip 43 First housing 44 Second membrane 44a Second opening edge 44b Second tip 45 Second housing 46 Rib 47 Connecting part 50 Pressure-sensitive part 250 Piezoelectric film 350 Pressure sensor CM Mixture CP Granules CA1 First fluid CA2 Second fluid MO Article

Claims

1. A gripping device capable of gripping an article, comprising: a drive unit; a support member operable by the drive unit; a bag provided on the support member and elastically deformable to conform to the shape of the article, comprising: a first membrane body formed to extend along an axis, having a first opening edge provided at an axial end and a first tip provided at an end opposite to the first opening edge; a second membrane body provided inside the first membrane body; a first containment section defined between the first membrane body and the second membrane body and capable of containing a mixture consisting of granules and a first fluid; a second containment section defined inside the second membrane body and capable of containing a second fluid; and a first pressure adjustment unit for adjusting the pressure of the first fluid contained in the first containment section.

2. The gripping device according to claim 1, further comprising a plurality of rib portions arranged in line around the axis between the first membrane and the second membrane, extending from the first opening edge toward the first tip portion, wherein the plurality of rib portions divide the first housing portion into a plurality of housing chambers.

3. The gripping device according to claim 2, wherein the plurality of rib portions equally divide the first housing portion.

4. The gripping device according to claim 2 or 3, wherein the first membrane, the second membrane, and the plurality of rib portions are formed of elastomer, and the plurality of rib portions are integrally molded with either the first membrane or the second membrane.

5. The gripping device according to any one of claims 1 to 4, wherein at least one of the first membrane, the second membrane, and the plurality of rib portions is made of piezoelectric rubber.

6. The gripping device according to any one of claims 1 to 5, further comprising a detection unit for detecting voltage or current, wherein the bag body is capable of outputting voltage or current toward the detection unit in contact with the article.

7. The gripping device according to any one of claims 1 to 6, further comprising a second pressure adjustment unit for adjusting the pressure of the second fluid housed in the second housing.

8. The gripping device according to claim 7, wherein when gripping an article with the bag, the bag elastically deforms upon contact with the article, the first pressure adjustment unit reduces the pressure in the first containment portion of the elastically deformed bag, and the second pressure adjustment unit reduces the pressure in the second containment portion after the first containment portion has been reduced by the first pressure adjustment unit.

9. The gripping device according to claim 8, wherein when an article gripped by the bag is released, the first pressure adjustment unit pressurizes the first containment portion of the elastically deformed bag, and the second pressure adjustment unit pressurizes the second containment portion after the first containment portion has been pressurized by the first pressure adjustment unit.

10. A method for gripping an article using a bag that is elastically deformable to conform to the shape of an article upon contact with the article, the bag comprising: a first membrane formed to extend along an axis; a second membrane provided inside the first membrane; a first containment section defined between the first membrane and the second membrane, capable of containing a mixture consisting of granules and a first fluid; and a second containment section defined inside the second membrane, capable of containing a second fluid, the method comprising: depressurizing the first containment section of the bag that has elastically deformed upon contact with the article; and depressurizing the second containment section after depressurizing the first containment section.

11. The method for gripping an article according to claim 10, wherein when releasing an article gripped by the bag, the first storage portion of the bag gripping the article is pressurized, and after pressurizing the first storage portion, the second storage portion is pressurized.

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