JP7549874B2 - Grasping device, robot arm and flying object using multi-fingered hand with iris mechanism - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. (1) Published in the proceedings of the Robotics and Mechatronics Symposium 2020 on May 27, 2020. (2) Published as a poster presentation at the Robotics and Mechatronics Symposium 2020 on May 29, 2020.

The present invention relates to a gripping device for gripping an object, and a robot arm and an aircraft equipped with the same.

Conventionally, a gripping device is known in which three or more movable members arranged around a gripping central axis move toward the gripping central axis by the driving force of a drive source, and the movable members grip the outer surface of the object to be gripped. For example, Patent Document 1 discloses a gripping device in which six flat movable blades (movable members) arranged adjacent to each other around the gripping central axis are arranged so that their plate surfaces form the same plane, and the adjacent surfaces (end surfaces) between adjacent movable blades slide against each other to move toward the gripping central axis. This gripping device grips the periphery of the object to be gripped arranged near the gripping central axis from all directions with the end surfaces of each movable blade (opposing parts facing the gripped part). Therefore, when the end surfaces (opposing parts) of the six movable blades abut against the outer surface of the object to be gripped, there is no escape route for the object to be gripped, and the object to be gripped is properly gripped.

JP 2020-040178 A

However, there are many objects that conventional gripping devices are not good at gripping. For example, if the object has a special outer surface shape, such as a cone shape that tapers toward the gripping central axis, or if the object is low in height, conventional gripping devices have difficulty gripping it properly.

In order to solve the above-mentioned problems, the present invention provides a gripping device in which three or more movable members arranged around a gripping central axis move each of the movable members toward the gripping central axis by the driving force of a driving source, thereby gripping the outer surface of an object to be gripped with the three or more movable members, wherein the opposing portions of the movable members facing the outer surface of the object to be gripped are approximately parallel to the gripping central axis and are elongated along the gripping central axis.
In this gripping device, three or more movable members arranged around a gripping central axis move toward the gripping central axis to grip the outer surface of the object to be gripped. Therefore, the object to be gripped can be gripped from its periphery, and when the opposing parts of the three or more movable members come into contact with the outer surface of the object to be gripped, the object can be gripped.
Here, in conventional gripping devices, the movable member was a flat member (movable blade), so if the object to be gripped had, for example, a special outer surface shape or was low in height, it could be difficult to grip properly, and there were many objects that were difficult to grip.
To explain this with a specific example, when gripping a low-height object, in a conventional gripping device, the holding member that holds the movable blade so that it can move protrudes outward from the plate surface of the movable blade. Therefore, when attempting to grip a low-height object placed on a placement surface, the holding member interferes with the placement surface, and the end surface (opposing portion) of the movable blade cannot face the object, making it impossible to grip the object.
In contrast, in the gripping device of the present invention, the opposing portion of the movable member that faces the outer surface of the object to be gripped is substantially parallel to the gripping central axis and is elongated along the gripping central axis. Due to this elongated shape, the long-dimension tip portion of the opposing portion can be configured to protrude outward in the gripping central axis direction further than other components including the holding member of the movable member. Therefore, when attempting to grip a low-height object to be gripped that is placed on a placement surface, the other components do not interfere with the placement surface, and the tip portion of the opposing portion of the movable member can be made to face the object to be gripped appropriately.

In addition, the present invention is characterized in that, in the gripping device, the three or more movable members move away from the gripping central axis, thereby gripping the inner surface of the object to be gripped by the three or more movable members.
In this gripping device, the three or more movable members can be moved away from the gripping central axis to grip the inner surface of the object to be gripped by these movable members. For example, by inserting the long opposing parts of the three or more movable members through the opening of a hole provided in the object to be gripped and moving the three or more movable members away from the gripping central axis, the opposing parts of the movable members can be brought into contact with the inner surface of the object to be gripped, thereby holding (gripping) the object to be gripped. Therefore, as long as the object to be gripped has an inner surface that can be gripped by the three or more movable members, the object to be gripped can be gripped regardless of the shape of the outer surface of the object to be gripped.

The present invention also provides a gripping device in which three or more movable members arranged around a gripping central axis are moved away from the gripping central axis by the driving force of a drive source, thereby gripping the inner surface of an object to be gripped with three or more movable members, and the opposing portion of the movable member facing the inner surface of the object to be gripped is approximately parallel to the gripping central axis and is elongated along the gripping central axis.
In this gripping device, the three or more movable members can be moved away from the gripping central axis to grip the inner surface of the object to be gripped by these movable members. For example, by inserting the long opposing parts of the three or more movable members through the opening of a hole provided in the object to be gripped and moving the three or more movable members away from the gripping central axis, the opposing parts of the movable members can be brought into contact with the inner surface of the object to be gripped, thereby holding (gripping) the object to be gripped. Therefore, as long as the object to be gripped has an inner surface that can be gripped by the three or more movable members, the object to be gripped can be gripped regardless of the shape of the outer surface of the object to be gripped.
In addition, in the gripping device, the opposing portion of the movable member that faces the outer surface of the object to be gripped is approximately parallel to the gripping central axis and is long along the gripping central axis. Therefore, even if the inner surface shape of the object to be gripped has a cone shape that tapers toward the gripping central axis, the opposing portion of the movable member comes into contact with the outermost periphery (edge) of the cone shape first and can grip the object to be gripped without sliding on the outermost periphery (edge).
Furthermore, even when gripping a low-height object to be grasped, for example, since the opposing portion of the movable member in this gripping device is long, the long-length end portion of the opposing portion can be configured to protrude outward in the gripping central axis direction further than other components including the holding member of the movable member. Therefore, when attempting to grip a low-height object to be grasped placed on the placement surface, the other components do not interfere with the placement surface, and the end portion of the opposing portion of the movable member can be made to face the inner surface of the object to be grasped, allowing it to be properly gripped.

In the gripping device according to the present invention, the three or more movable members move while being spaced apart from one another in the circumferential direction of the gripping central axis.
In this gripping device, even if the wall (outer surface or inner surface) of the object to be gripped facing the opposing portion of the movable member has a special shape, such as an asymmetric shape or an irregular shape, the object can be properly gripped by the opposing portion of the movable member. For example, in the case of an object to be gripped having a special shape with a protruding portion on the wall, in a conventional gripping device with no gap between the movable members, one of the movable members abuts against the protruding portion, and many of the other movable members are unable to abut against the wall of the object to be gripped. In contrast, with this gripping device, the protruding portion can enter the gap between the movable members, so that more movable members can abut against the object to be gripped, and the object to be gripped can be gripped more appropriately.
In addition, according to the present gripping device, as the movable members approach the gripping central axis, the distance between them decreases and the gap between the movable members narrows, so that it is possible to grip the object to be gripped in the gap between the movable members. As a result, even if an object to be gripped that is long in a direction perpendicular to the gripping central axis is positioned away from the gripping central axis, it is possible to grip the object to be gripped in the gap between the two movable members.

The present invention is also characterized in that the gripping device has a holding member that holds the three or more movable members so that they can move, and the three or more movable members are capable of moving to a position farther from the gripping center axis than the holding member.
In this gripping device, the three or more movable members can be moved to a position farther from the gripping central axis than the holding member, so that an object to be gripped can be gripped that has dimensions larger than the holding member in a plane perpendicular to the gripping central axis.

In the gripping device according to the present invention, the opposing portion is made of an elastic material.
In this gripping device, since the facing portion is elastically deformable, even if the object to be gripped is fragile, the object can be gripped while dispersing the contact pressure appropriately by elastic deformation. Furthermore, when gripping an object to be gripped on a placement surface, the placement surface and the facing portion are unlikely to be damaged even if the facing portion collides with the placement surface. Moreover, since the object to be gripped on the placement surface can be gripped with the facing portion elastically deformed along the placement surface, a low object to be gripped placed on the placement surface can be more appropriately gripped.

In the gripping device according to the present invention, the three or more movable members are moved by a driving force of one of the driving sources.
This gripping device can be made lighter and smaller than a configuration in which three or more movable members are moved by a plurality of drive sources.

In the gripping device according to the present invention, the drive source is disposed at a position through which the gripping central axis passes.
In a gripping device in which three or more movable members arranged around a gripping central axis are moved toward or away from the gripping central axis, the center of the gripping device roughly coincides with the gripping central axis, and therefore, if the center of gravity of the gripping device is positioned near the gripping central axis, a gripping device with good weight balance can be obtained.
However, in conventional gripping devices, it is necessary to secure a space for passing the object through the gripping central axis so that the flat movable blade can grip the side of a relatively long object. Therefore, in conventional gripping devices, it is necessary to place a relatively heavy drive source at a position away from the gripping central axis, and as a result, the center of gravity of the gripping device is significantly away from the gripping central axis, resulting in poor weight balance.
In contrast, as described above, in the present gripping device, since the opposing portion of the movable member is long, it is possible to grip the side of a relatively long object to be gripped with the opposing portion of the tip side of the movable member without inserting the end of the relatively long object to be gripped all the way to the base end of the movable member (the end held by the holding member). Therefore, as in the present gripping device, it is possible to arrange the drive source at a position through which the gripping central axis passes. And, by being able to arrange the relatively heavy drive source at a position through which the gripping central axis passes, a configuration with less imbalance in weight balance can be realized.

The present invention is also characterized in that, in the gripping device, the three or more movable members move by rotating around each of the rotation axes arranged around the gripping central axis so as to be approximately parallel to the gripping central axis.
According to this gripping device, the movement of each movable member (movement toward or away from the gripping central axis) can be achieved with a simple configuration.

In addition, the present invention is characterized in that, in the gripping device, the movable member comprises a long gripping member along the gripping central axis and a support member supporting one end side of the gripping member, and the gripping member moves by moving the support member using the driving force of the driving source.
In the gripping device, the other end (tip side) of the gripping member can be a free end, so the gripped part can be gripped by the opposing part at the tip side of the gripping member. This makes it possible to grip the gripped object without the other component getting in the way, compared to a configuration in which the tip side of the gripping member is connected to another component.

The present invention is also characterized in that the holding device has two support members that sandwich and support a drive transmission member that transmits a driving force from the drive source to the three or more movable members in the axial direction of the holding central axis, and one of the two support members is a holding member on the opposite side to the side supporting the drive transmission member and holds the three or more movable members so that they can move.
In conventional gripping devices, the movable member is a flat plate-like member (movable blade), and the movable blade is supported by being sandwiched between two support members in the axial direction of the gripping central axis together with a drive transmission member (gear or pulley) that transmits the driving force from a drive source. In this configuration, for example, when changing the size of the drive transmission member to change the transmission ratio of the drive speed (gear ratio, etc.), it is necessary to change the size of the movable member and the support member in accordance with this change.
In the present invention, only the drive transmission member is sandwiched between the two support members, and the movable member is not sandwiched between them. By adopting a configuration in which the movable member is held outside the two support members in this manner, even if the size of the drive transmission member is changed to change the transmission ratio of the drive speed, it is not necessary to change the size of the movable member or the support members accordingly.

The present invention also provides a robot arm equipped with a gripping device for gripping an object to be gripped, characterized in that the gripping device described above is used as the gripping device.
With this robot arm, it is possible to reduce the types of objects that the robot arm is not good at grasping, thereby providing a robot arm with greater versatility.

The present invention also provides an aircraft equipped with a gripping device for gripping an object to be gripped, characterized in that the gripping device is the gripping device described above.
With this flying object, it is possible to reduce the types of objects that are difficult to grasp, thereby providing a flying object with greater versatility.

The present invention can reduce the number of objects that are difficult to grasp, and provide a highly versatile grasping device.

FIG. 1 is an explanatory diagram showing an overview of a part assembly system according to a first embodiment. FIG. 2 is an external perspective view of a robot arm in the part assembly system, as viewed obliquely from above. FIG. 2 is a perspective view for explaining an iris multi-fingered robot hand used as an end effector of the robot arm. FIG. 4 is a perspective view of the iris multi-fingered robot hand, seen from an angle different from that of FIG. 3 . 13A to 13E are explanatory diagrams of the iris multi-fingered robot hand as viewed from the second holding member side, for illustrating the grasping operation of the iris multi-fingered robot hand. 4A to 4C are explanatory diagrams showing the configuration of the gripping members of the finger members in the Iris multi-fingered robot hand. FIG. 11 is an explanatory diagram showing an example of using the Iris multi-fingered robot hand to grasp an object having a small dimension in a direction perpendicular to the central axis of grasping. FIG. 13 is an explanatory diagram showing an example of using the Iris multi-fingered robot hand to grasp an object having a cone shape whose outer surface tapers toward the central axis of the grasp. FIG. 11 is an explanatory diagram showing an example of using the Iris multi-fingered robot hand to grasp an object whose length in the direction parallel to the central axis of grasping is very short. FIG. 11 is an explanatory diagram showing an example of using the Iris multi-fingered robot hand to grasp an object having dimensions larger than a holding member in a virtual plane perpendicular to the central axis of grasping. 13A and 13B are explanatory diagrams showing an example of using the Iris multi-fingered robot hand to grasp a long object in a direction perpendicular to the central axis of the grasp. FIG. FIG. 13 is an explanatory diagram showing an example in which the Iris multi-fingered robot hand is used to abut the gripping members of the six finger members against the inner surface of a hole in an object to be gripped, thereby holding (grasping) the object. FIG. 11 is a schematic diagram showing a drone according to a second embodiment.

[Embodiment 1]
Hereinafter, an embodiment in which a gripping device according to the present invention is applied as an end effector of a robot arm (hereinafter, this embodiment will be referred to as "Embodiment 1") will be described.
In this embodiment, a robot arm is used to pick up a part from a transport case in which the part is loaded in an assembly factory where parts are assembled, and the part is placed in a predetermined position on a part transport conveyor in an assembly line. However, the gripping device according to the present invention, which is applied to such a robot arm, is merely an example, and may be applied to a robot arm used in another system, or may be used as a gripping device other than a robot arm.

FIG. 1 is an explanatory diagram showing an overview of a part assembly system according to the first embodiment.
In the part assembly system 1 of the present embodiment 1, the parts in the transport case 50 placed at the part removal position 2a are placed at a predetermined position on the transport conveyor 45 of the part assembly system by the robot arm 10, and the parts transported by the transport conveyor 45 are used for assembly in a subsequent assembly process. The empty transport case 50 is moved to the case recovery position 2b.

FIG. 2 is an external perspective view of the robot arm 10 as seen obliquely from above.
The robot arm 10 has a base portion 11, a lifting portion 12 supported so as to be able to rise and fall relative to the base portion 11, a first arm portion 13 supported so as to be rotatable around a first rotation axis 13a relative to the lifting portion 12, a second arm portion 14 supported so as to be rotatable around a second rotation axis 14a relative to the first arm portion 13, and a hand portion 15 supported so as to be rotatable around a third rotation axis 15a relative to the second arm portion 14.

The lifting unit 12 is attached to the slide rail of the base 11 so that it can be raised and lowered, and is configured to be able to move up and down along the slide rail of the base 11 in the direction indicated by arrow A in the figure by the driving force of the lifting motor 12b. The base end of the first arm 13 is attached to the lifting unit 12 so that it can rotate 360° in the direction indicated by arrow B in the figure around a first rotation axis 13a, which is a vertical axis that passes through the center of the base 11. The base end of the second arm 14 is attached to the tip end of the first arm 13 so that it can rotate 360° in the direction indicated by arrow C in the figure around a second rotation axis 14a, which is a vertical axis that passes through the tip end of the first arm 13.

The base end of the hand 15 is attached to the tip end of the second arm 14 so that it can rotate 360° in the direction indicated by the arrow D in the figure around a third rotation axis 15a, which is a vertical axis passing through the tip end of the second arm 14. Various types of end effectors can be attached and detached to the hand 15, and in this embodiment 1, an Iris multi-fingered robot hand 20 is attached.

FIG. 3 is a perspective view for explaining the iris multi-fingered robot hand 20 used as an end effector of the robot arm 10.
FIG. 4 is a perspective view of the iris multi-fingered robot hand 20 of the first embodiment, seen from an angle different from that of FIG.
5(a) to (e) are explanatory diagrams of the iris multi-fingered robot hand 20 viewed from the tip side of the finger members, for explaining the gripping operation of the iris multi-fingered robot hand 20 of this embodiment 1.
In addition, in order to show the internal configuration of the iris multi-fingered robot hand 20, a first holding member 22, which will be described later, is depicted as being transparent in Figures 3 and 4.

The Iris multi-fingered robot hand 20 of this embodiment 1 has six finger members 21A, 21B, 21C, 21D, 21E, and 21F as multiple movable members arranged around the gripping central axis O. All of the finger members 21A to 21F of this embodiment 1 have the same configuration. It is also possible to use a combination of movable members of different configurations. The number of finger members can be set arbitrarily to three or more, but is preferably five or more.

In the iris multi-fingered robot hand 20 of this embodiment 1, two disk-shaped holding members 22, 23 are arranged facing each other with a predetermined distance between them. The iris multi-fingered robot hand 20 is attached to the hand end portion 15 of the robot arm 10 via the first holding member 22 of the two holding members 22, 23.

As shown in Figs. 3 and 4, one drive motor 26 is attached as a drive source to the motor fixing portion 22a on the first holding member 22 in this embodiment 1. The drive motor 26 is capable of rotating forward and reverse, and may be, for example, a servo motor. The drive motor 26 is disposed at a position through which the gripping central axis O passes. In this way, by disposing the relatively heavy drive motor 26 at a position through which the gripping central axis O passes, the center of gravity of the Iris multi-fingered robot hand 20 is located near the gripping central axis O, and a configuration with less imbalance in weight balance is realized.

In addition, in this embodiment 1, the motor shaft 26a of the drive motor 26 is arranged so as to be located on the gripping central axis O. Therefore, the drive transmission mechanism for transmitting the drive force from one drive motor 26 to the six finger members 21A, 21B, 21C, 21D, 21E, and 21F arranged around the gripping central axis O can be configured to be point symmetrical with respect to the motor shaft 26a, making it easy to reduce the number of parts, standardize parts, and simplify the configuration.

The motor shaft 26a of the drive motor 26 arranged on the first holding member 22 is rotatably supported by the first holding member 22 and the second holding member 23. A motor gear 26b constituting a drive transmission mechanism is fixed to the motor shaft 26a in the portion between the first holding member 22 and the second holding member 23.

In addition, three idler gears 25 constituting a drive transmission mechanism are arranged in the space between the first holding member 22 and the second holding member 23 so as to mesh with the motor gear 26b. The three idler gears 25 are arranged point symmetrically with respect to the motor shaft 26a, and the shaft 25a of each idler gear 25 is rotatably supported by the first holding member 22 and the second holding member 23.

In addition, six drive gears 24A-24F constituting a drive transmission mechanism are arranged in the space between the first holding member 22 and the second holding member 23 so that two of them mesh with each of the idler gears 25. The six drive gears 24A-24F are also arranged point symmetrically about the motor shaft 26a, and the shafts 24a of the drive gears 24A-24F are also rotatably supported by the first holding member 22 and the second holding member 23.

In the first embodiment, the drive transmission mechanism is configured using gears, but the present invention is not limited to this and may be configured in other ways, such as using a belt.
In addition, in this embodiment 1, the six finger members 21A to 21F are moved by driving force from one driving source, but the six finger members 21A to 21F may be moved by driving forces from two or more driving sources.

Each shaft 24a of the six drive gears 24A to 24F extends from the outer surface of the second holding member 23, and six finger members 21A to 21F are attached to the extending portions. Specifically, the six finger members 21A to 21F are composed of a long gripping member 21a along the gripping central axis O, and a support blade 21b, which is a support member that supports one end of the gripping member 21a.

The support blade 21b is a long, flat member, and is arranged so that its plate surface is parallel to the outer surface of the second holding member 23. The shaft 24a of the drive gears 24A to 24F is fixed to one end of the support blade 21b, and the gripping member 21a is attached to the other end of the support blade 21b. As a result, when the drive gears 24A to 24F are driven to rotate, the support blade 21b rotates around the shaft 24a centered on the one end, and in conjunction with this rotation, the gripping member 21a fixed to the other end of the support blade 21b rotates and moves around the shaft 24a.

The gripping member 21a of each finger member 21A to 21F is a long rod-shaped member that is supported by the support blade 21b so that its longitudinal direction is approximately parallel to the gripping central axis O. In this embodiment, the side portion of the gripping member 21a becomes a facing portion that faces the outer side or inner side of the object to be gripped. Therefore, the facing portions (side portions of the gripping member 21a) of the finger members 21A to 21F in this embodiment are approximately parallel to the gripping central axis O and are long along the gripping central axis.

FIG. 6 is an explanatory diagram showing the configuration of the gripping members 21a of the finger members 21A to 21F in the first embodiment.
The gripping member 21a of the present embodiment 1 is composed of one or more core materials 21c having high rigidity extending in the longitudinal direction, and an elastic material 21d molded to cover the periphery of the core material. The core material 21c is preferably made of a metal such as aluminum, and the core material 21c of the gripping member 21a is connected to and supported by the support blade 21b. The elastic material 21d is formed of a rubber material such as silicone rubber, and the material is appropriately selected. The elasticity of the elastic material 21d of the gripping member 21a can be adjusted not only by adjusting the material, but also by providing a notch or an internal space.

Further, the shape of the gripping member 21a in the first embodiment is a quadrangular prism with a trapezoidal bottom as shown in FIGS. 5(a) to 5(e), but the shape can be determined appropriately.
In particular, in the present embodiment 1, the six finger members 21A to 21F rotate around the respective shafts 24a as described above, thereby moving the gripping members 21a closer to or farther away from the gripping central axis O. Therefore, the shapes of the gripping members 21a are determined so that they do not interfere with (contact with) each other during the movement.

The shape of the gripping members 21a in this embodiment 1 is determined so that the side surfaces (facing parts) of the gripping members 21a come into contact with each other when they are closest to the gripping central axis O, as shown in FIG. 5(e). If the configuration creates a gap, it is not possible to grip an object to be gripped that has dimensions smaller than the gap. In contrast, if the configuration is such that the side surfaces (facing parts) of the gripping members 21a come into contact with each other when they are closest to the gripping central axis O, as in this embodiment 1, and no gaps are created, it is possible to grip even an object to be gripped T1 that has a small dimension in the direction perpendicular to the gripping central axis O, as shown in FIG. 7.

Next, the movements of the six finger members 21A to 21F will be described in more detail with reference to FIGS.
In the first embodiment, when the drive motor 26 is driven, the driving force is transmitted to the six finger members 21A to 21F via the motor gear 26b, the idler gear 25, and the drive gears 24A to 24F. As a result, the support blades 21b of the six finger members 21A to 21F rotate around the shafts 24a of the drive gears 24A to 24F, and the gripping members 21a attached to the other ends of the support blades 21b rotate around the shafts 24a.

In this embodiment 1, the drive motor 26 is driven in the reverse direction, so that each of the gripping members 21a of the six finger members 21A to 21F rotates around the shaft 24a in the clockwise direction in FIG. 5. As a result, the six finger members 21A to 21F move until each of the gripping members 21a is located at the farthest point from the gripping central axis O, as shown in FIG. 5(a).

When the drive motor 26 is driven in the forward direction with the six finger members 21A to 21F open in this manner, the gripping members 21a of the six finger members 21A to 21F rotate around the shaft 24a in the counterclockwise direction in FIG. 5. As a result, the six finger members 21A to 21F move so that the gripping members 21a approach the gripping central axis O, as shown in FIGS. 5(b) to (e). Then, finally, as shown in FIG. 5(e), the gripping members 21a of the six finger members 21A to 21F move to a position where one side of the gripping member 21a contacts each other on the gripping central axis O, and the six finger members 21A to 21F are completely closed.

When the robot arm 10 is to grasp a part in the carrying case 50, for example, as shown in FIG. 5(a), the Iris multi-fingered robot hand 20 with the six finger members 21A-21F open is moved to a position where it can grasp the part in the carrying case 50 by controlling the rotation of each axis of the robot arm 10. Then, the drive motor 26 is driven to move the six finger members 21A-21F so that their grasping members 21a approach the grasping central axis O. When moved in this manner, the side faces of the grasping members 21a of the six finger members 21A-21F come into contact with the side face of the part, and the part is grasped.

Now, for example, consider the case of grasping an object T2 as shown in FIG. 8, that is, an object T2 having a cone-shaped outer surface tapering toward the gripping central axis O. In a conventional grasping device (configured to grasp an object placed near the gripping central axis from all directions with the end faces of six movable blades), when the end faces of the movable blades come into contact with the cone-shaped outer surface of the object T2, the object T2 slides along the outer surface. Therefore, even if the cone-shaped outer surface of the object T2 continues to press against the end faces of the movable blades, the object T2 escapes in the direction of the gripping central axis O and cannot be grasped properly.

In contrast, in the Iris multi-fingered robot hand 20 of this embodiment 1, the side surfaces (facing portions) of the gripping members 21a of the six finger members 21A to 21F that face the outer surface of the object to be grasped T2 are approximately parallel to the gripping central axis O and are elongated along the gripping central axis O. Therefore, even if the outer surface shape of the object to be grasped T2 has a cone shape as shown in FIG. 8, the side surfaces (facing portions) of the gripping members 21a come into contact first with the outermost periphery (edge) of the cone shape, and the object to be grasped T2 can be properly grasped without sliding on the outermost periphery (edge).

9, for example, consider a case where a low-height object T3, i.e., an object T3 with a very short length in a direction parallel to the gripping central axis O, is gripped. In a conventional gripping device, for such an object T3, a holding member that holds the movable blade so as to be movable protrudes in the direction of the gripping central axis beyond the plate surface of the movable blade. Therefore, when an attempt is made to grip a low-height object T3 placed on a placement surface, the holding member interferes with the placement surface, and the end face (opposing portion) of the movable blade cannot be opposed to the outer surface of the object T3, and the object cannot be gripped.

In contrast, in the Iris multi-fingered robot hand 20 of the present embodiment 1, the side surfaces (facing portions) of the gripping members 21a of the six finger members 21A to 21F are elongated along the gripping central axis O. Due to such an elongated shape, the tip portions of the gripping members 21a in the elongated direction are configured to protrude further in the direction of the gripping central axis O than the other components including the holding members 22 and 23. Therefore, when attempting to grip a low-height object to be grasped T3 placed on a placement surface, the other components do not interfere with the placement surface, and the tip portions of the gripping members 21a of the six finger members 21A to 21F can be made to face the outer surface of the object to be grasped T3, and the object to be grasped T3 can be appropriately gripped.

In addition, as shown in FIG. 5(a), the Iris multi-fingered robot hand 20 of this embodiment 1 can move the six finger members 21A to 21F to a position farther away from the gripping central axis O than the holding members 22, 23 that hold them. Therefore, as shown in FIG. 10, it is possible to grip an object to be gripped T4 that has dimensions larger than the holding members 22, 23 in an imaginary plane perpendicular to the gripping central axis O.

In the Iris multi-fingered robot hand 20 of this embodiment 1, the six finger members 21A to 21F move closer to the gripping central axis O while being spaced apart from each other in the circumferential direction of the gripping central axis O. Therefore, as the six finger members 21A to 21F approach the gripping central axis O, the distance between them becomes smaller. As a result, for example, as shown in FIG. 11(a) and FIG. 11(b), it is possible to grasp a long object T5 to be grasped in a direction perpendicular to the gripping central axis O by sandwiching it between the gaps between the gripping members 21a of each finger member 21A to 21F. In particular, according to this embodiment 1, even if the long object T5 is located in a position that is off the gripping central axis O, it can be grasped by sandwiching it between the two finger members 21D and 21E as shown in FIG. 11(b).

In addition, as described above, the Iris multi-fingered robot hand 20 of this embodiment 1 can move the six finger members 21A to 21F so that each of the gripping members 21a of the six finger members 21A to 21F moves away from the gripping central axis O by driving the drive motor 26 in the reverse direction. As a result, for example, as shown in FIG. 12, by inserting the gripping members 21a of the six finger members 21A to 21F in a closed state through the opening of the hole Ta provided in the object to be grasped T6 and moving the six finger members 21A to 21F so that each of the gripping members 21a moves away from the gripping central axis O, the side surfaces (facing parts) of the gripping members 21a of the six finger members 21A to 21F can be abutted against the inner side of the hole Ta of the object to be grasped T6, and the object to be grasped T6 can be held (grasped).

In addition, in this embodiment 1, as described above, the side portion (opposing portion) of the gripping member 21a is formed of the elastic material 21d, so that the side portion (opposing portion) of the gripping member 21a can be elastically deformed. As a result, even if the object to be gripped is fragile, for example, the gripping force can be appropriately dispersed by elastic deformation while gripping the object. In addition, when gripping an object to be gripped on a placement surface, since the tip portion of the gripping member 21a is formed of the elastic material 21d, the placement surface and the gripping member 21a are unlikely to be damaged even if the tip portion collides with the placement surface. Moreover, since the tip portion of the gripping member 21a can grip the object to be gripped on the placement surface with elastic deformation along the placement surface, for example, a gripping object T3 having a low height on the placement surface as shown in FIG. 9 can be appropriately gripped.

In addition, in conventional gripping devices, the movable member is a flat plate-shaped member (movable blade), and the movable blade is sandwiched between two support members together with the drive transmission member (gear or pulley). In this case, for example, when changing the size of the drive transmission member to change the transmission ratio (gear ratio) of the drive speed, it is necessary to change the size of the movable blade and the support member accordingly.

In contrast, in the first embodiment, only the drive transmission mechanism as a drive transmission member is sandwiched between the two support members, the first holding member 22 and the second holding member 23, and the finger members 21A-21F as movable members are not sandwiched. By configuring the finger members 21A-21F to be held on the outside of the first holding member 22 and the second holding member 23 in this way, even if the size of the drive transmission member is changed to change the transmission ratio (gear ratio) of the drive speed, it is not necessary to change the size of the finger members 21A-21F or the holding members 22, 23 accordingly.

Furthermore, in conventional gripping devices, the movable member is a flat plate-shaped member (movable blade), and the adjacent surfaces (end surfaces) of adjacent movable blades slide against each other to move toward the gripping central axis. This configuration has the disadvantage that the driving load due to sliding is large, making it difficult to increase the operating speed. In contrast, the configuration of this embodiment 1 does not generate such driving load due to sliding, and therefore has the advantage that it is easy to increase the operating speed.

On the other hand, in this embodiment 1, the object to be grasped is grasped with the long finger members 21A to 21F, so the grasping force is easily lost due to bending of the finger members 21A to 21F, and the grasping force is likely to be weaker than in conventional grasping devices that grasp the object to be grasped with the end face (opposing part) of a flat member (movable blade). In this regard, it is possible to obtain the desired grasping force, for example, by adjusting the transmission ratio (gear ratio, etc.) of the drive transmission member.

As described above, the Iris multi-fingered robot hand 20 of this embodiment 1 can properly grasp objects of various shapes and sizes, including objects that were difficult to grasp with conventional grasping devices.

[Embodiment 2]
Next, we will explain another embodiment (hereinafter, this embodiment will be referred to as "embodiment 2") in which the gripping device of the present invention is applied as a gripping device of an aircraft equipped with a gripping device that grips an object to be gripped.
In the present embodiment 2, the Iris multi-fingered robot hand 20 of the above-described embodiment 1 is adopted as a gripping device mounted on a drone as an air vehicle. Therefore, a description of the Iris multi-fingered robot hand 20 will be omitted.

FIG. 13 is a schematic diagram showing a drone 100 according to the second embodiment.
The drone 100 of the second embodiment has a configuration in which the Iris multi-fingered robot hand 20 of the first embodiment described above is attached to the lower part of a known drone body 101. According to the drone 100 of the second embodiment, for example, in a flying state or a landed state, a transport object (object to be grasped) present below the drone body 101 can be grasped by the grasping members 21a of the six finger members 21A to 21F of the Iris multi-fingered robot hand 20. Then, by flying the drone 100 in a state where the transport object is grasped, the transport object can be transported to a destination.

As described in the above-mentioned embodiment 1, the Iris multi-fingered robot hand 20 used in the drone 100 of this embodiment 2 is capable of grasping a variety of objects that have been difficult to grasp properly with conventional grasping devices. Therefore, according to this embodiment 2, it is possible to realize a highly versatile transport drone with few restrictions on the objects to be transported.

The Iris multi-fingered robot hand 20 used in the drone 100 of this embodiment 2 has a simple structure and is lightweight because it can be driven by a single drive source (actuator). Therefore, it can be suitably used as a robot hand for the drone 100, for which lightweight is important. In particular, the Iris multi-fingered robot hand 20 of this embodiment 1 has little imbalance in weight balance as described above, so it can be mounted in the horizontal center position of the drone 100 body, and has the advantage of being less susceptible to changes in the center of gravity when grasping an object to be grasped.

Furthermore, in the drone 100 of this embodiment 2, by opening the six finger members 21A-21F of the Iris multi-fingered robot hand 20, the six finger members 21A-21F can function as landing legs of the drone 100. In this case, by closing the six finger members 21A-21F of the Iris multi-fingered robot hand 20, it is also possible to grasp an object to be grasped while keeping the drone 100 in a landing state.

1: Parts assembly system 10: Robot arm 11: Base 12: Lifting section 13: First arm 14: Second arm 15: Hand 20: Iris multi-fingered robot hand 21A to 21F: Finger member 21a: Gripping member 21b: Support blade 21c: Core material 21d: Elastic material 22: First holding member 23: Second holding member 24A to 24F: Drive gear 25: Idler gear 26: Drive motor 26a: Motor shaft 26b: Motor gear 45: Transport conveyor 50: Transport case 100: Drone 101: Drone body O: Grip central axis T1 to T6: Object to be gripped

Claims (13)

A gripping device in which three or more movable members arranged around a gripping central axis are moved toward the gripping central axis by a driving force of a driving source, thereby gripping an outer surface of a gripped object with the three or more movable members,
The opposing portion of the movable member opposing the outer surface of the object to be grasped is configured to be substantially parallel to the gripping central axis and to protrude in the direction of the gripping central axis,
A gripping device characterized in that the three or more movable members are shaped so that when they approach the gripping central axis closest to each other, the opposing portions of the movable members come into contact with each other and no gaps are created . The gripping device according to claim 1,
A gripping device characterized in that the three or more movable members grip the inner surface of the object to be gripped by moving away from the gripping central axis. The gripping device according to claim 1 or 2 ,
The three or more movable members are configured so that the tip end portions of the opposing parts in the direction of the central axis of gripping are positioned at the most distal ends of the movable members . The gripping device according to any one of claims 1 to 3,
A gripping device characterized in that the three or more movable members move while being spaced apart from each other in the circumferential direction of the gripping central axis. The gripping device according to any one of claims 1 to 4,
a holding member that holds the three or more movable members so as to enable the movements;
A gripping device characterized in that the three or more movable members are movable to a position farther from the gripping central axis than the holding member. The gripping device according to any one of claims 1 to 5,
A gripping device, wherein the opposing portion is made of an elastic material. The gripping device according to any one of claims 1 to 6,
A gripping device, characterized in that the three or more movable members are moved by a driving force of one of the driving sources. The gripping device according to any one of claims 1 to 7,
The gripping device is characterized in that the drive source is disposed at a position through which the gripping central axis passes. The gripping device according to any one of claims 1 to 8,
A gripping device characterized in that the three or more movable members perform the movement by rotating around respective rotation axes that are arranged around the gripping central axis so as to be approximately parallel to the gripping central axis. The gripping device according to any one of claims 1 to 9,
The movable member comprises a gripping member configured to protrude in the direction of the gripping central axis and a support member supporting one end side of the gripping member, and the gripping device is characterized in that the gripping member moves by moving the support member using the driving force of the driving source. The gripping device according to any one of claims 1 to 10,
a drive transmission member that transmits a drive force from the drive source to the three or more movable members, and two support members that sandwich and support the drive transmission member in an axial direction of the grip central axis;
A gripping device characterized in that one of the two support members is a holding member that holds the three or more movable members so that they can move, on the side opposite to the side that supports the drive transmission member. A robot arm equipped with a gripping device that grips an object to be gripped,
A robot arm using the gripping device according to any one of claims 1 to 11 as the gripping device. An aircraft equipped with a gripping device that grips an object to be gripped,
12. An aircraft using the gripping device according to claim 1 as the gripping device.

Images