Robot hand for grasping fragile objects

Abstract

To provide a robot hand for gripping a fragile object capable of gripping fragile aquatic product, food or the like.SOLUTION: A robot hand 1 for gripping a fragile object includes two gripping frame bodies 4 which are reciprocated in directions away from and close to each other by a driving source 2, an expanding gripping member 5 which is fixed so as to be freely expandable in a direction orthogonal to directions away from and close to the frame bodies 4, a thin belt-like scooping-up member 6 provided in the same direction to the expanding gripping member 5 on a lower end of the gripping frame bodies 4 and a shock buffer member 7 which mitigates a shock upon grounding of the gripping frame bodies 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a robot hand for gripping fragile objects, capable of gripping fragile seafood such as raw oysters. [Background technology]

[0002] Conventionally, soft and fragile foods such as fragile seafood change shape easily, so even if they are grabbed, they change shape and fall, making them difficult to grasp even with hands that are suitable for soft objects. Conventional hands made of soft materials have been researched, and there are soft grippers (for example, Non-Patent Document 1). In addition, binding hands have been devised that grasp and lift fragile objects by surrounding them with a single thread instead of fingers (for example, Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Zhongkui Wang, Yuuki Torigoe, and Shinichi Hirai, A Prestressed Soft Gripper: Design, Modeling, Fabrication, and Tests for Food Handling, IEEE Robotics and Automation Letters, Vol.2, Issue 4, pp.1909-1916 2017. [Non-Patent Document 2] Hisashi Iwamasa and Sinichi Hirai: “Binding of Food Materials with a Tension-Sensitive Elastic Thread”, Proc. IEEE Int. Conf. on Robotics Automation, pp.4298-4303, 2015. Summary of the Invention [Problem to be solved by the invention]

[0004] However, soft and fragile foods such as fragile seafood are easily deformed and slippery, making them difficult to grasp even with a hand that is suitable for soft foods.In addition, in the case of a binding hand that encircles and grasps and lifts a soft and fragile object such as fragile seafood with a single thread, it is difficult to grasp and lift the object, so it is necessary to grasp and lift the object in a container, which is time-consuming. [Means for solving the problem]

[0005] The present invention has been made in consideration of the above circumstances, and its means include two clamping frames that are reciprocated by a drive source in a direction in which they approach each other, and a clamping frame fixed to the clamping frames so as to be expandable and contractible in a direction perpendicular to the direction in which the clamping frame moves away from the other, Sandwich An expandable clamping member that clamps and holds an object placed on the placement surface when the holding frames move toward each other, and a clamping mechanism that is provided at the lower end of the clamping frame in the same direction as the expandable clamping member. The width is wide so that the area in contact with the bottom surface of the fragile object is large. A thin ribbon-shaped scooping member and a reaction force buffering member that buffers the impact when the clamping frame touches the ground; The thin strip-shaped scooping member is Sandwich The robot hand for gripping fragile objects is characterized in that when the holding frame moves close to the object, it slides between the bottom surface of the fragile object and the placement surface, scoops it up, and supports the fragile object from below. The clamping frame is a gate-shaped frame having a main frame fixed to the driving source and a pair of support columns fixed downward on both sides of the main frame. Furthermore, the telescopic clamping member is A main frame fixed to the drive source, and a pair of support columns fixed downward on both sides of the main frame. The elastic member is a plurality of elastic thread-like members having both ends fixed therebetween. Furthermore, the telescopic clamping member is A main frame fixed to the drive source, and a pair of support columns fixed downward on both sides of the main frame. The point is that it is an elastic planar member fixed on both sides between the two. Furthermore, the reaction force buffer member is A main frame fixed to the drive source and a pair of The support pillar is an elastic body that urges the support pillar downward relative to the base frame. Moreover, the reaction force buffer member is A main frame fixed to the drive source and a pair of It is a leaf spring whose both ends are fixed to the lower part of the support pillar. Furthermore, the leaf spring also serves as the thin ribbon-like scooping member. Furthermore, the present invention is a robot using the robot hand for gripping a fragile object. Effect of the Invention

[0006] According to the robot hand for gripping fragile objects of the present invention configured as described above, when gripping and moving a gripping object such as soft and fragile food such as fragile seafood, the gripping object lands on the placement surface so that it is located between the two clamping frames from the state of moving through the air, and the reaction force buffer member prevents damage to the clamping frames and other equipment at the time of landing even if there is an unevenness in the control of the descent speed of the robot arm. After landing, the two clamping frames approach each other by the drive source to grip the gripping object located between them, and as both telescopic clamping members approach each other, the telescopic clamping members press the softer parts of the gripping object rather than the harder parts, so that the entire gripping object can be wrapped around.

[0007] At the same time, the thin ribbon-shaped scooping members slip between the underside of the object to be grasped and the placement surface from both sides, so that when the robot arm rises to lift the object to be grasped, not only the sides and top of the object to be grasped are surrounded by the expandable clamping members, but the bottom surface is also lifted at the same time, so that even objects that are prone to losing their shape can be moved easily.

[0008] In addition, when the telescopic clamping member is a plurality of telescopic thread-like members, many gaps are formed, so that it can be suitably used for objects with protrusions, irregular shapes, or hard objects to be clamped. When the telescopic clamping member is a telescopic planar member, it is suitable for objects to be clamped that are more fragile, small, have a smooth outer shape, or are slippery. A mixture of telescopic thread-like members and telescopic planar members may be used. When the shock absorbing member is an elastic body that urges the support column downward relative to the base frame, the entire clamping frame body can be uniformly cushioned, so that the life of the device can be extended. When the shock absorbing member is a leaf spring, it can be used in combination with a thin strip-shaped scooping member, so that the entire device can be simplified.

[0009] A robot equipped with a robot arm equipped with such a robot hand for gripping fragile objects can be effectively used to alleviate labor shortages in food factories with large production volumes, such as lunch boxes. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an overall perspective view of an embodiment of a robot hand for gripping a fragile object; [Diagram 2] FIG. 13 is an overall perspective view of another embodiment of a robot hand for gripping a fragile object; [Diagram 3] FIG. 2 is an explanatory overall perspective view of the embodiment of FIG. 1 in a state in which a fragile object is sandwiched; [Figure 4] FIG. 13 is an explanatory overall perspective view of another embodiment in a state where a fragile object is sandwiched; [Diagram 5] FIG. 13 is an overall perspective view of another embodiment of a robot hand for gripping a fragile object attached to a moving body; [Figure 6] A perspective view of the scooping member with shock absorbing members attached to both ends [Figure 7] FIG. 7 is a bottom perspective view of another embodiment of the robot hand for gripping a fragile object to which the cushioning member of FIG. 6 is attached. [Figure 8] A vertical cross-sectional view of a fragile object being clamped [Figure 9] Bottom view of the fragile object in Figure 8 being pinched [Figure 10]Schematic diagram of the robot arm [Figure 11] FIG. 2 is a view of the embodiment of FIG. 1 as seen obliquely from below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As can be clearly seen in Figure 1, the robot hand 1 for gripping fragile objects of this invention has two clamping frames 4 that are moved toward and away from each other by a moving body 21 driven by the drive source 2 at a position below a main body 3 that has a built-in pneumatic actuator, which is a drive source 2 that drives left and right by sucking and discharging air pressure, and are provided with these clamping frames 4. An extendable clamping member 5 is fixed to the clamping frame 4 in a direction perpendicular to the approaching and retracting direction in which the clamping frame 4 moves linearly. The extendable clamping member 5 is fixed to the lower end 431 of the clamping frame 4. Sandwich A thin ribbon-shaped scooping member 6 is fixed in the same direction as the tension direction of the holding member 5, and further, the clamping frame 4 is provided with a reaction force buffer member 7 to cushion the impact when the clamping frame 4 lands. When the main body 3 is connected to a robot arm C as shown in Fig. 10, the clamping frame 4 can be moved up and down by controlling the up and down movement of the robot arm C via a control device (not shown). However, a lifting device (not shown) may be provided inside the main body 3 so that the clamping frame 4 can be moved up and down together with the robot arm C or independently.

[0012] The driving source 2 is not particularly limited and may be driven by electricity, magnetism, or the like other than a pneumatic actuator. The driving of the driving source 2 is controlled by a control device based on information sensed by a sensor device (not shown) such as the position of the fragile object A on the placement surface B and the state of the object being pinched by the pinching frame 4, and is controlled to stop, drive left and right, i.e., in the direction of approaching or moving away from each other, and drive up and down, such as lowering or raising. These driving mechanisms are housed inside the main body 3, but as they use known technology, their description will be omitted.

[0013] The clamping frame 4 is connected to the driving source 2 and moves while being guided by a rail 8 provided below the main body 3 so as to move toward and away from each other in a linear direction. The movable body 21 is provided with a connecting member 41 connected and fixed to the connecting member 41, a main frame 42 fixed at the upper middle part to the connecting member 41 and suspended so that its longitudinal direction is perpendicular to the moving direction of the movable body 21, and a support pillar 43 which passes through both ends of the main frame 42 and is supported so as to be movable up and down. The movable body 21 and the connecting member 41 are detachably fixed by screws 9. In addition, a coil spring 71 is fitted onto the support pillar 43 as an impact buffer member 7 for absorbing an impact when a lower end 431 of the support pillar 41 abuts against a placement surface B of the fragile object A. The upper end of this coil spring 71 abuts against the underside of the backbone frame 42, and the lower end abuts against the upper end of the mounting portion 431 of the support pillar 43 which fixes the telescopic clamping member 5. As a result, the support pillar 43 is constantly biased downward relative to the backbone frame 42, and a locking screw 433 which serves as a stopper for locking the support pillar 43 in a predetermined position is screwed into a position above the backbone frame 42 so that it can move up and down by rotating.

[0014] The stretching Sandwich In the embodiment shown in FIG. 1, the support member 5 is composed of a set of elastic thread-like members 51, both ends of which are engaged with a pair of support columns 43 that pass through both ends of the main frame 42 and are supported so as to be movable up and down. The way in which the thread-like members 51 are engaged with the support columns 43 is not particularly limited, but a single long thread-like member 51 may be wound around the mounting parts 432 of the pair of support columns 43 in sequence so that the thread-like member 51 is stretched in the vertical direction. The thread-like members 51 may be stretched by fixing both ends of each thread in the vertical direction inside the pair of mounting parts 432. The vertical interval between the thread-like members 51 is not particularly limited, and may be determined depending on the type of the fragile object A. The vertical interval is determined depending on the type of the fragile object A, as well as the thickness and tensile strength of the thread-like members 51 and the degree of softness or hardness of the surface. Furthermore, the thread-like members 51 located in the center of the attachment part 432, which has a high proportion of contact with and clamping against the fragile object A, may be made of a material that stretches easily, while the thread-like members 51 located above or below may be made of a material that does not stretch easily, so that the physical properties of the thread-like members 51 vary depending on the attachment position. Silicone threads are preferably used as the thread-like members 51.

[0015] In addition, the stretch Sandwich 2, the support member 5 may be a flexible sheet member 52 having both lateral ends fixed to the attachment portion 432. Examples of the flexible sheet member 52 include a thin synthetic resin sheet, a synthetic resin film, a net-like member in which fibers are woven lengthwise, widthwise, or diagonally, a nonwoven fabric, and a cloth.

[0016] The thin strip-shaped scooping member 6 is shown in all of Figs. 1 to 11, but as is particularly shown in Figs. 4, 8 and 9, Sandwich This is a useful member for scooping up fragile object A by sliding against the frictional force generated between the bottom surface of fragile object A and the placement surface B such as the conveyor surface of said fragile object A when the support frames 4 move toward each other. A thin ribbon-shaped member made of hard synthetic resin is preferably used, but it may also be a thin metal plate such as stainless steel. And both ends of the member are Sandwich It is fixed to the lower surface of a pair of support columns 43, which are also the lower ends 431 of the frame 4, and when it descends, the entire surface comes into contact with the placement surface B. The wider the width of the scooping member 6, the larger the area of ​​contact with the bottom surface of the fragile object A, making it easier to scoop it up. However, if it is not possible to increase the width of the lower ends 431 of the support columns 43 to match, it is possible to provide an attachment piece 61 protruding inward and make one of the longitudinal edges of the scooping member 6 protrude inward to face each other, as shown in Figure 2. Both the front and back surfaces of the scooping member 6 slide against the placement surface B and the bottom surface of the fragile object A, so it is preferable to form them into slippery surfaces. It is also desirable to mold it so that its thickness is as thin as possible, so that the above-mentioned hard synthetic resin plate and thin metal plate strip are preferably used as materials that meet such conditions.

[0017] In the embodiment of the shock absorbing member 7 shown in FIG. 1, an example in which a coil spring 71 is used has been described, but FIG. 5 shows another embodiment in which a leaf spring 72 that can also be used as the scooping member 6 is used instead of this coil spring 71. In this other embodiment, as can be clearly seen in the figure, both end portions 721 of the scooping member 6 made of a metal such as stainless steel and fixed to the lower end 431 of the support column 43 by welding or the like are curved 180 degrees to provide a spring mechanism. As a result, when the main body 3 descends, Sandwich The impact when the lower end 431 of the support frame 4 hits the placement surface B can be absorbed and mitigated by the cushioning effect of the curved portion of the leaf spring 72, and in terms of preventing adverse effects on the devices housed in the main body 3, the same impact cushioning effect as the impact cushioning material 7 using the coil spring 71 can be obtained. In addition, since it is a thin metal strip or plate, it can be used as the scooping member 6. In the case of this scooping member 6, the support columns 43 at both ends of the main frame 42 are fixed since they do not need to move up and down. In this embodiment, the cushioning effect is obtained by curving both ends of the thin metal strip scooping member 6, but the central portion of the scooping member 6 may also be curved downward, in which case after the cushioning effect, Sandwich It is necessary to constantly apply a constant downward pressure to the holding frame 5 so as to keep it in a flat, straight line so that the scooping members 6 can easily enter between the bottom surface of the fragile object A and the placement surface B. In the case of such leaf springs 72, there is no need to structure the support columns 43 so that they can move up and down relative to the main frame 42, which has the advantage of simplifying the structure of the device itself.

[0018] FIG. 6 shows yet another embodiment in which leaf springs 73 are used at both ends of the scooping member 6. As shown in the figure, this embodiment is an example in which leaf springs 73 are interposed between the two lower ends 431 of the support column 43 and both ends of the scooping member 6 to form the shock absorbing member 7. The leaf springs 73 may be made of the same elastic material as the scooping member 6 and bent at both ends, or may be made as separate parts and interposed between the lower ends 431 and the upper surfaces of both ends of the scooping member 6 by connecting them with fasteners or the like. In this embodiment, the leaf springs 73 can cushion the collision when the lower ends of the support columns 43 are placed on the placement surface B, so that the transmission of shock to other equipment is mitigated. Note that the leaf springs 73 in this embodiment may be replaced by other elastic bodies such as coil springs.

[0019] The fragile object gripping robot hand 1 configured as above is characterized in that it pinches the fragile object A from both sides and slides the scooping member 6 under the bottom surface, so the configuration has been explained. However, when actually using the robot hand for arranging ingredients, etc., the fragile object A gripped in this way must be moved to a predetermined position, so it must be moved upward, rotated, and horizontally. Figure 10 As shown in FIG. 1, this operation is performed by the operation of the robot arm C to which the fragile object gripping robot hand 1 is attached, so its explanation is omitted.

[0020] The operation of the robot hand 1 for gripping fragile objects of this invention, configured as described above, will be described below for the case where a fragile object A is placed on a placement surface B, such as the surface of a moving conveyor or the top surface of a tray placed on a table, and the object is grasped and placed in a designated position in a lunch box. In the case of a conveyor, the object is constantly being transported, so the robot arm C is controlled to follow the movement of the object, and placement surface B is, in effect, stationary.

[0021] As shown in FIG. 10, when a robot hand 1 for grasping a fragile object attached to the tip of a robot arm C detects, by a sensor device (not shown), that a fragile object A is present at a predetermined position on a placement surface B, a pair of sensors are operated based on the position information. SandwichExpanding and contracting the body 4 Sandwich The fragile object A is moved so that it fits between the support members 5 with a small gap between them. At this time, the sensor device simultaneously measures the length and width of the fragile object A in a plan view and calculates the two Sandwich The spacing between the frame members 4 and the contact position of the scooping member 6 on the placement surface B are calculated, and based on this information, the robot arm C operates by controlling the movement of the main body 3. The vertical movement of the main body 3 may be performed by providing a lifting device on the main body 3 instead of the robot arm C. Sandwich The shock generated when the lower end 431 of the support frame 4 comes into contact with the surface is absorbed by the shock absorbing member 7 and is not transmitted to the main body 3, thereby ensuring the safety of the entire device.

[0022] Next, the moving body 21 of the driving source 2 is actuated, Sandwich When the frame members 4 move in the direction toward each other, they expand and contract. Sandwich The holding members 5 sandwich the fragile object A from both sides. At the same time, the scooping members 6 slide between the bottom surface of the fragile object A and the placement surface B from both sides. Sandwich The support member 5 not only contacts the side surface of the fragile object A, but also, as shown in FIG. Sandwich As the support bodies 4 approach each other, they come into contact with the upper and lower outer peripheries and enclose the entire object, thereby supporting the fragile object A from below and preventing it from falling or losing its shape during transportation. Sandwich As the holders 4 approach each other, the scooping members 6 also enter between both sides of the bottom surface of the fragile object A and the placement surface B, as shown in Figs. Sandwich The movement of the frame members 4 in the direction in which they approach each other is as follows: Sandwich The moving body 21 is controlled to automatically stop when the contact pressure against the weak object A reaches a certain level or more even before the opposing surfaces of the support body 4 come into contact with each other.

[0023] As mentioned above SandwichWhen the sensor detects that the frame 4 has wrapped the entire outer periphery of the fragile object A, the robot arm C lifts up, or if the main body 3 has a lifting device, it is lifted by this, and the fragile object A leaves the placement surface B and is transported to a specified location by the robot arm C and placed there. For example, the fragile object A may be an omelette, which is carried to a specified location in a box of side dishes in a lunch box where many are lined up. Once the placement is complete, a pair of arms are lifted up, in the opposite direction to the above. Sandwich The frame members 4 move in directions away from each other and are stretched and contracted from the fragile object A. Sandwich After the holding member 5 and the scooping member 6 are separated, the empty object is lifted up and moved to a position to hold the next fragile object A. By repeating such operations in sequence, the operations of holding, moving and placing the fragile object A are repeated, and the work that has conventionally been performed manually by an operator can be performed by the robot.

[0024] Depending on various factors such as the hardness and softness of the entire fragile object A, its characteristics such as its external shape and size, and the condition of its outer surface, Sandwich Strength, size, and expansion of the frame 4 Sandwich When the thickness, attachment interval, stretching strength, thickness, material, etc. of the thread-like member 51 of the support member 5 are changed, the moving body 21 and Sandwich The connecting member 41 of the holding frame 4 can be freely replaced by removing the screw 9 that connects and fixes it, so the range of applications is wide. In addition, to state another effect of the present invention, the scooping member 6 can scoop up the fragile object A, so it is possible to hold the fragile object A, which was difficult to hold only from the side. In addition, the thread or film can hold the fragile object A by wrapping it around it in order to maintain its flexibility. Furthermore, it is possible to hold the fragile object A by surrounding it from all sides. In addition, since a relatively thin or narrow material such as a thread, a thin plate, or a thin film is used, it is possible to hold the object even if the gap between the fragile objects A is small, and it is possible to use it in a narrow place, so the range of applications is expanded. In addition, since it has a mechanism for reducing the impact at the time of collision by the impact buffer member 7, there is no problem with contact when the placement surface B of the fragile object A and the lower end 431 of the main frame 42 come into contact with each other.

[0025] (Experimental Example) The experimental results when fragile object A was grasped using the fragile object grasping robot hand 1 of this invention are shown in Table 1. A circle indicates a case where the object was successfully grasped and moved to the designated position, a triangle indicates a case where the object was successfully grasped but the movement to the designated position was not completed due to, for example, the object dropping during the movement, and an X indicates a case where the object failed to be grasped. [Table 1] (Experimental Results) From Table 1, it can be seen that stable gripping by scooping is generally possible. It can be seen that the binding effect is high for relatively large objects such as hamburger steaks and fried chicken, allowing for stable gripping. It can also be seen that hamburger steaks and fried chicken are not smooth relative to placement surface B, making them easier to scoop, which has a positive effect on gripping. However, in the case of rolled omelets, it is thought that the cause of failure is that the scooping member does not penetrate under the bottom of the object, but instead pinches the side of the object. [Industrial Applicability]

[0026] This invention can be used in various fields where various fragile foods are handled, since it allows the robot to handle food and marine products, which are particularly thin and slippery. For example, it can be used in packing side dishes for lunch boxes, serving dishes in fragile containers such as china, etc. Furthermore, it can be used in packing glasswork, fruits, vegetables, and other agricultural products for transportation. Also available It can be used effectively. [Explanation of symbols]

[0027] 1. Robot hand for grasping fragile objects 2. Power Source 21 Mobile 3. Main unit 4 Sandwich Frame holder 41 Connecting material 42 Core Framework 43 Support pillar 431 Bottom end 432 Mounting part 433 Locking screw 5. Stretch Sandwich Supporting material 51 Thread-like member 52 Soft sheet material 6. Scooping material 7. Shock mitigation material 71 Coil spring 72 Leaf spring 721 Both ends 73 Leaf Spring 8 Rail 9 Screws A. Vulnerable object B Placement surface C Robot Arm

Claims

1. Two clamping frames that are reciprocated in mutually approaching and separating directions by a drive source; an expandable clamping member fixed to the clamping frame so as to be expandable in a direction perpendicular to the approaching and retracting direction, and configured to clamp and hold a fragile object placed on a placement surface when the clamping frames move closer to each other; A thin ribbon-shaped scooping member having a large width and provided at the lower end of the clamping frame in the same direction as the expandable clamping member so as to increase the area in contact with the bottom surface of the fragile object; A reaction force buffering member that buffers the impact when the clamping frame touches the ground; Equipped with A robot hand for gripping fragile objects, characterized in that the thin ribbon-shaped scooping member slides between the bottom surface of the fragile object and the placement surface when the clamping frame moves close to the object, scooping it up and supporting the fragile object from below.

2. 2. The robot hand for gripping fragile objects according to claim 1, characterized in that the clamping frame is a gate-type frame having a main frame fixed to the drive source and a pair of support pillars fixed downward on both sides of the main frame.

3. The robot hand for gripping fragile objects as described in claim 1, characterized in that the telescopic clamping member is a plurality of telescopic thread-like members whose both ends are fixed between a main frame fixed to the drive source and a pair of support pillars fixed downward on both sides of the main frame.

4. The robot hand for gripping fragile objects as described in claim 1, characterized in that the telescopic clamping member is an telescopic planar member fixed on both sides between a main frame fixed to the drive source and a pair of support pillars fixed downward on both sides of the main frame.

5. 2. A robot hand for gripping fragile objects as described in claim 1, characterized in that the reaction force buffering member is an elastic body that biases a main frame fixed to the drive source and a pair of support pillars fixed downward to both sides of the main frame downwardly against the main frame.

6. 2. The robot hand for gripping fragile objects according to claim 1, characterized in that the reaction force buffering member is a leaf spring having both ends fixed to the lower parts of a main frame fixed to the drive source and a pair of support pillars fixed downward on both sides of the main frame.

7. 7. The robot hand for gripping a fragile object according to claim 6, wherein the leaf spring also serves as the thin strip-shaped scooping member.

8. A robot using a robot hand for grasping fragile objects as defined in any one of claims 1 to 7.

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