JP7679566B2 - Robot hand and drone equipped with same - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act Seibu Construction Co., Ltd. and Tokyo University of Science, a school corporation, submitted to the Architectural Institute of Japan a paper on the robot hand and the drone equipped with the robot hand invented by Hiroyuki Miyauchi, Manabu Kanematsu, Ken Koto, Kentaro Futamura, Katsusaburo Kawamae and Ryo Kitamura, March 31, 2023 to April 4, 2023.

The present invention relates to a robotic hand and a drone equipped with the same.

Drones have become popular worldwide in recent years, driven by advances in technology such as smartphones and the Internet. A drone is an unmanned aircraft that can fly remotely or automatically, and is also known as a multicopter.

Drones can be used to transport cargo, take aerial photographs, and inspect areas that are difficult to do manually, such as the exterior walls of high-rise buildings, using pre-installed cameras and inspection equipment.

In particular, for transporting luggage, a drone equipped with a robot hand has been proposed, as shown in Patent Document 1.
This robot hand (end effector) is provided at the tip of a link mechanism that constitutes a robot arm, and is mechanically constructed from parts having rigidity, including the robot arm.

Patent No. 6371959

Incidentally, when a drone equipped with a robotic arm such as that described in Patent Document 1 is used not only for transporting luggage as described above but also for inspecting exterior walls, it is expected that the robotic hand will be tethered to a mooring object such as a handrail in order to stabilize the drone's flying position.

However, with the robot hand described above, there was a problem in that there was a risk of damaging the object being moored during mooring, making it difficult to actively use it for inspecting exterior walls, etc.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a robot hand device and a drone equipped with the same that improves convenience without damaging the object to be moored during mooring.

To solve the above problems, the present invention provides a robot hand device that is attached to a drone,
A robot hand body simulating a human hand and a finger opening/closing means for opening and closing each finger of the robot hand body,
At least the outer circumferential surface of the robot hand body is made of a flexible material.

According to the present invention, the outer peripheral surface of the robot hand body is formed from a flexible material, so that when an operator anchors the robot hand body to an object to be anchored, the operator can stabilize the flight position of the drone without damaging the object to be anchored.

In a preferred embodiment of the present invention, the entire robot hand body is made of a soft material.

With this configuration, even if the robot hand body is strongly tethered to the tethering object, there is no risk of damaging the tethering object, and the drone's flight position can be made more stable.

In a preferred embodiment of the present invention, the finger opening and closing means is configured to be capable of performing opening and closing operations independently for each finger.

This configuration allows the operator to not only moor the robot hand body to the mooring object, but also to stably hold a specified inspection device, luggage, etc. according to its shape, improving the convenience of this robot hand device.

In a preferred embodiment of the present invention, the finger opening/closing means includes a rope member having one end fixed to the tip end side of each of the fingers and the other end extending to the base end side of each of the fingers, and a pulling means for pulling each of the rope members toward the base end side of each of the fingers,
The fingers are biased in the open direction by the elastic force of the soft material, and are configured to transition to a closed state when the rope members are pulled by the pulling means.

This configuration makes it possible to open and close each finger with a simple structure without introducing complex components into the robot hand itself, which contributes to weight reduction and reduced risk of failure.

In a preferred embodiment of the present invention, the traction means includes a bobbin around which each of the rope members is wound, and a rotation means for rotating the bobbin in a direction in which each of the rope members is wound, and the rotation means is a motor that can be remotely driven and controlled.

This configuration makes it possible to easily perform tasks such as mooring to mooring targets on higher floors, required inspection work, and transporting luggage to higher floors while maintaining a simple configuration, improving the convenience of this robot hand device.

In a preferred embodiment of the present invention, the robot hand includes an arm portion having multiple joints extending from the base end of the robot hand body, and the base end of the arm portion is attached to the top surface of the drone.

This configuration prevents the arm from interfering with the drone's propellers while increasing the range of motion of the robot hand body, improving the convenience of this robot hand device in a variety of usage situations.

The present invention also relates to a drone equipped with the robot hand device described above.

The present invention provides a robot hand device and a drone equipped therewith that are convenient and do not damage the object being moored during mooring.

FIG. 1 is a perspective view showing a drone according to an embodiment of the present invention. 1A and 1B are enlarged views partially showing the configuration of a robot hand device according to an embodiment of the present invention, in which FIG. 5A to 5C are side views showing an operation mode of the arm portion according to the embodiment of the present invention. 5A to 5C are side views showing an operation mode of the arm portion according to the embodiment of the present invention. FIG. 2 is a bottom view showing the robot hand body and the finger opening/closing means according to the embodiment of the present invention. 1A to 1C are bottom views showing an operation mode of the robot hand main body according to the embodiment of the present invention. FIG. 1 is a diagram showing a usage mode of a drone according to an embodiment of the present invention. FIG. 1 is a diagram showing a usage mode of a drone according to an embodiment of the present invention. FIG. 1 is a diagram showing a usage mode of a drone according to an embodiment of the present invention. FIG. 1 is a diagram showing a usage mode of a drone according to an embodiment of the present invention. 13A to 13C are diagrams illustrating a modified example of the robot hand body according to the embodiment of the present invention.

Hereinafter, a robot hand device and a drone equipped with the same according to an embodiment of the present invention will be described with reference to Figures 1 to 11.
It should be noted that the embodiment described below is merely an example of the present invention, and the present invention is not limited to the embodiment described below.
In these figures, reference numeral 1 denotes a robot hand device W according to this embodiment, and reference numeral A denotes a drone equipped with the robot hand device.

<Configuration>
The configurations of the robot hand device W and the drone A will be described below with reference to Figures 1 to 6.
For ease of explanation, the direction indicated by the arrow in FIG. 1 will be referred to as the tip side or forward, and the opposite direction will be referred to as the base side or rear.

As shown in FIG. 1, the robot hand device W is attached to the drone A and includes a pair of robot hand bodies 1 that mimic human hands, finger opening/closing means 2 that causes each of the fingers f1 to f5 of each robot hand body 1 to perform an opening/closing operation, and an arm portion 3 that extends from the base end of the robot hand body 1 and has multiple joints (joints j1 to j6, a first motor m1, and a second motor m2).

In this embodiment, the drone A has a configuration similar to that of drones that are generally available, and includes a drone body A1 with a built-in battery, arms A2 extending in all four directions from the drone body A1, propellers A3 attached to each arm A2, and a pair of legs A4 protruding downward from the drone body A1.

A control means P is provided on the top surface of the drone body A1 to control the rotation of the propeller A3 as well as the operation of the finger opening/closing means 2 and the arm section 3, but this may be incorporated inside the drone A.

Each robot hand body 1 is entirely made of a soft material, and each of the fingers f1 to f5 is biased in a direction toward an open state by the elastic force of the soft material.
Although each robot hand body 1 is entirely made of silicone, the present invention is not limited to this, as long as the fingers f1 to f5 are made of a soft material that allows opening and closing movements.
A more specific configuration of each robot hand body 1 will be described later with reference to FIGS.

A pair of finger opening/closing means 2 is provided corresponding to each robot hand body 1 .
In this embodiment, each finger opening/closing means 2 has a housing 21 that is inverted T-shaped when viewed from the front, and a first arm 31 (described later) is inserted into an insertion hole provided in the upper part of the housing 21. As a result, each finger opening/closing means 2 is fixed so as to be suspended from the tip side of the first arm 31.
A more specific configuration of each finger opening/closing means 2 will be described later with reference to FIG.

A pair of arm units 3 are provided corresponding to each robot hand body 1 .
Each arm portion 3 has a first arm portion 31 extending in the vertical direction, a second arm portion 32 extending in the front-to-rear direction, a base portion 33 for supporting the base end of the first arm portion 31 on the top surface of the drone main body A1, and a wrist portion 34 provided at the tip of the second arm portion 32.
Furthermore, each arm portion 3 has a first cylinder S<b>1 that controls the movement of the first arm portion 31 , and a second cylinder S<b>2 that controls the movement of the second arm portion 32 .
A more specific configuration of each arm portion 3 will be described later with reference to the schematic diagram of FIG.

FIG. 2( a ) is a side view of the tip end side and surrounding area of the second arm portion 32 , with the side wall of the housing 21 of the finger opening/closing means 2 omitted.
As shown in FIG. 2 , the rope member 22 enters the inside from the opening at the tip of the second arm portion 32 , is pulled out to the outside via a through hole (not shown), and is pulled into the inside of the finger opening and closing means 2 .
In addition, the conductive wire C is pulled out to the outside through a through hole (not shown) on the back surface of the finger opening/closing means 2, and pulled into the inside of the second arm portion 32 through a through hole (not shown) in the second arm portion 32.

In FIG. 2(a), the cord member 22 and the conductor C that are pulled out to the outside or pulled into the finger opening/closing means 2 are shown by thin solid lines and dashed lines, respectively.

As shown particularly in FIG. 2(b), the wrist portion 34 is composed of a first motor m1 provided at the tip of the second arm portion 32, and a second motor m2 connected to the motor shaft of the first motor m1 via a bracket b.
The rotation axis direction of the first motor m1 is along the left-right direction, and the rotation axis direction of the second motor m2 is along the direction in which the first arm 31 extends, so that wrist bending and rotation movements can be performed for each robot hand body 1.

In Figure 2 (b), the cylindrical housing h that contains the second motor m2 and the base end of the robot hand main body 1 is shown by a dotted line, and the rope member 22 pulled out from the base end of the robot hand main body 1 is shown by a thin solid line.
Further, the motor shaft of the second motor m2 is contained within the base end side of each robot hand body 1.

The configuration and operation of the arm unit 3 will be described below with reference to FIGS.
In addition, in Figures 3 and 4, the arm portion 3 is illustrated diagrammatically, with the first arm portion 31, the second arm portion 32, and the piston rods S11 and S21 being shown by solid lines, the joint portions j1 to j6 and the first motor m1 being shown by white circles, the cylinder tubes S12 and S22 being shown by white rectangles, and the bracket t being shown by a rectangle with diagonal hatching.
3 and 4, the finger opening/closing means 2 is omitted.

As shown in FIG. 3A, the first arm 31 and the second arm 32 have their distal and proximal ends connected by a joint j1, and are configured to be rotatable relative to each other about the joint j1 as an axis.
In addition, the first arm portion 31 and the second arm portion 32 are both hollow, and a cord member 22 and a conductor C, which will be described later, are inserted therethrough.
Furthermore, the conductor C is pulled out from inside the first arm 31 to inside the drone body A1 and connected to the control means P.

The base portion 33 is connected to the base end of the first arm portion 31 by the joint portion j2, so that the first arm portion 31 can rotate around the joint portion j2.

For the first cylinder S1, the tip of the piston rod S11 is connected to a joint j3 provided on the first arm 31, and the base end of the cylinder tube S12 is connected to a joint j4 provided on the top surface of the drone body A1.

For the second cylinder S2, the tip of the piston rod S21 is connected to a joint j5 provided on the second arm 32, and the base end of the cylinder tube S22 is connected to a joint j6 provided on the first arm 31.

The joints j3, j5, and j6 protrude from the outer peripheral surface of a cylindrical bracket t fixed to the first arm portion 31 or the second arm portion 32.
In addition, the joints j1 to j6 all have their rotation axes extending in the left-right direction and are configured to be substantially parallel to one another.

An operator can slide the piston rod S11 of the first cylinder S1 to place the arm portion 3 in the state shown in FIG. 3(a) to FIG. 3(b), for example.
In other words, the operator can move the robot hand body 1 mainly along the forward/backward direction by changing the angle between the top surface of the drone body A1 and the first arm 31.

An operator can slide the piston rod S21 of the second cylinder S2 to place the arm portion 3 in the state shown in Figs. 3(a) to 3(c), for example.
That is, the operator can move the robot hand body 1 mainly in the vertical direction by changing the angle between the first arm portion 31 and the second arm portion 32.

By driving the first motor ml, the arm unit 3 can be put into the state shown in, for example, FIG. 4(a) to FIG. 4(b).
That is, the operator can perform a wrist bending operation on the robot hand body 1.

By driving the second motor m2, the arm unit 3 can be put into the states shown in Figs. 4(a) to 4(c), for example.
That is, the operator can perform a wrist rotation operation on the robot hand main body 1.

The sliding motion of the piston rods S11, S21 and the driving of the first motor m1 and the second motor m2 can be controlled via a control means P using a remote controller (not shown).
Also, while FIG. 4C shows an example in which the image is rotated 90 degrees so that the palm of the hand is visible, it is of course also possible to rotate the image 90 degrees so that the back of the hand is visible.

By combining the above-mentioned operations, the operator can shape the arm unit 3 and the robot hand main body 1 into the desired configuration.

The configurations of the robot hand body 1 and the finger opening/closing means 2 will be described in detail below with reference to FIGS.
5, finger opening/closing means 2 is shown with the bottom surface of housing 21 removed, showing its internal structure.

As shown in FIG. 5, multiple notches n are formed on the palm side of the robot hand body 1, and inside the robot hand body 1, a main passage portion p1 and a sub-passage portion p2 corresponding to each rope member 22 described later are formed.

More specifically, the cuts n are made up of joint cuts n1 corresponding to the joints of each finger f1 to f5, the ball of the foot cuts n2 formed at the boundary between the area corresponding to the ball of the foot and other areas, and base cuts n3 formed across the base of each finger f1 to f5.

The main passage portions p1 are generally cylindrical tube-shaped bodies, and are provided adjacent to each other in the left-right direction inside the palm.
In addition, the open end of the main passage portion p1 through which the rope member 22 pulling the thumb portion f1 is inserted is exposed from the thenar notch n2, and the open ends of the main passage portion p1 through which the rope members 22 pulling the other finger portions f2 to f5 are inserted are exposed from the base notch n3.

The sub-passage portion p2 is a generally cylindrical tube-shaped body that is smaller in diameter and shorter than the main passage portion p1. Multiple sub-passage portions p2 are provided inside each of the fingers f1 to f5, and their open ends are exposed from the joint cut n1, the ball cut n2, and the base cut n3.

As shown in FIG. 5, the finger opening/closing means 2 has, as an internal configuration of the housing 21, a rope member 22 having one end fixed to the tip side of each of the finger portions f1 to f5 and the other end extending to the base end side of each of the finger portions f1 to f5, a plurality of pulling means 23 for pulling each of the rope members 22 to the base end side of each of the finger portions f1 to f5, and a substrate 24.

More specifically, the cord member 22 is a string that is inserted from the tip of each of the fingers f1 to f5 into the sub-passage portion p2 and the main passage portion p1, and is pulled out into the interior of the cylindrical housing h and then pulled into the interior of the housing 21.
Further, each rope member 22 is exposed to the outside at the notch n.
Furthermore, the housing 21 is provided with a pair of small rollers r corresponding to each of the traction means 23, and each rope member 22 is pulled into the inside of the housing 21 in a manner such that it is clamped by each of the small rollers r.

The traction means 23 includes a plurality of bobbins 23a around which the rope members 22 are wound, and a rotation means 23b that rotates each bobbin 23a in a direction in which each rope member 22 is wound.
That is, one bobbin 23a and one rotating means 23b constitute a unit for winding one rope member 22, and five such units are arranged in the left-right direction.
Each of the rotating means 23b is a motor whose driving can be controlled remotely.

The substrate 24 is provided on the inner peripheral surface of the housing 21, and is electrically connected to the conductors c extending from each of the rotating means 23b.
In addition, the conductor C extending from the substrate 24 passes through the inside of the second arm portion 32 and the first arm portion 31 and is electrically connected to the control means P inside the drone main body A1.

The robot hand body 1 having the above-mentioned configuration operates, for example, as shown in FIG. 6 by the finger opening/closing means 2 having the above-mentioned configuration.
That is, for example, by driving the rotating means 23b corresponding to the rope members 22 of the thumb portion f1, the ring finger portion f4, and the little finger portion f5 and winding them up, the finger portions f1, f4, and f5 are bent (closed) by the joint notches n1 in substantially the same manner as in an actual human hand, and the robot hand main body 1 assumes a so-called scissors-like state as shown in FIG. 6(a).
Also, for example, by bending each of the fingers f1 to f5 by the finger opening/closing means 2 in the same manner as described above, the robot hand body 1 can assume a so-called fist-like configuration as shown in FIG. 6(b).
In addition, since each of the fingers f1 to f5 can be opened and closed independently, the operator can arbitrarily select which fingers to close and which fingers to open.

<Usage>
Hereinafter, the manner of use of the drone A equipped with the robot hand device W will be described with reference to Figures 7 to 10.

As shown in FIG. 7, the worker can use the robot hand device W to moor the drone A to the balcony railing k1, which is the mooring target K.

That is, the worker flies drone A while opening each of the fingers f1 to f5, and brings the palm of each robot hand body 1 into contact with the handrail k1.
Then, the operator closes each of the fingers f1 to f5 using the finger opening/closing means 2, and causes each robot hand body 1 to grasp the handrail k1.

Here, drone A can be equipped with a specified inspection device (not shown) such as an infrared camera in the area shown in the dotted circular frame in Figure 7 (a), and in the state shown in Figure 7, a worker can inspect the exterior wall using this inspection device.
At this time, the worker can adjust the position (angle and distance relative to the exterior wall) of drone A and the inspection device by operating the arm unit 3.

Note that Figure 7(a) is a side view of drone A when it is moored to handrail k1, and Figure 7(b) is a perspective view of the robot hand device W, with drone A omitted from Figure 7(a), showing only each robot hand body 1.

As shown in FIG. 8, the worker can use the robot hand device W to moor the drone A to the balustrade k2 of the balcony, which is the mooring target K.

That is, the worker flies drone A while opening each of the fingers f1 to f5, and brings the palm of each robot hand main body 1 into contact with the handrail k2.
Then, the operator closes each of the fingers f1 to f5 using the finger opening/closing means 2, and causes each robot hand body 1 to grip the handrail k2.
In this case, the wrists 34 of the robot hand bodies 1 are moved from the state shown in FIG. 1 so that the palms of the hands face each other.

In this case, too, it is similar to the case shown in Figure 7 in that a specified inspection device is provided and the positions of the drone A and the inspection device can be adjusted by the arm unit 3.
Note that Figure 8(a) is a side view of the drone A when it is moored to the handrail k2, and Figure 8(b) is an oblique view of the robot hand device W, with the drone A omitted from Figure 8(a), showing only each robot hand body 1.

As shown in FIG. 9, a worker can have one of the robot hand bodies 1 hold a predetermined work tool Z1 (in this embodiment, an electric drill).
In this case, if a trigger is provided on the handle of the work tool Z1, the worker can further pull each of the rope members 22, for example, with respect to the index finger portion f2 and the middle finger portion f3, thereby strongly bending each of the finger portions f2 and f3 toward the palm, thereby performing the trigger pressing operation.

As shown in FIG. 10, an operator can make each robot hand body 1 hold a load Z2 packed in a packing material of a predetermined shape.
In this case, the worker adjusts the angle and relative position of each robot hand body 1 and the bending degree of each finger portion f1 to f5 so as to stably hold the load Z2 in accordance with the shape of the load Z2.

＜Effects＞
According to this embodiment, the entire robot hand body 1 is formed from a soft material, so that even if the robot hand body 1 is tightly moored to the mooring object K, there is no risk of damaging the mooring object K, and the flight position of the drone A can be made more stable.

In addition, the finger opening and closing means 2 allows the operator to not only moor the robot hand main body 1 to the mooring object K, but also to stably hold a specified work tool Z1, luggage Z2, etc. according to their shape, improving the convenience of the robot hand device W.

Furthermore, the elasticity of the soft material causes each of the fingers f1 to f5 to be biased in the direction of the open state, and the rope member 22 is pulled by the pulling means 23 to transition to the closed state. This allows the fingers f1 to f5 to be opened and closed with a simple configuration without introducing a complex configuration into the robot hand body 1, which contributes to weight reduction and reduced risk of failure.

In addition, since the towing means 23 includes a bobbin 23a and a rotating means 23b, which is a motor that can be driven and controlled remotely, it is possible to easily perform tasks such as mooring to a mooring object K on a higher floor, performing specified inspection work, and transporting luggage Z2 to a higher floor while maintaining a simple configuration, thereby improving the convenience of the robot hand device W.

In addition, the arm portion 3 increases the range of motion of the robot hand main body 1 while preventing interference with the propeller A3, thereby improving the convenience of the robot hand device W in various usage modes.
<Example of change>

The shapes and dimensions of each component shown in the above embodiment are merely examples and can be modified based on design requirements, etc.

For example, each of the fingers f1 to f5 may have the configuration shown in Fig. 11. Fig. 11 is a cross-sectional view of any one of the fingers f1 to f5.
That is, in FIG. 11, the inside of each of the fingers f1 to f5 is hollow, and the main passage portion p1 extends to the base end of each of the fingers f1 to f5, so that the hollow portion communicates with the main passage portion p1.
Each of the finger portions f1 to f5 includes a flexible thin plate-like body v (for example, a plastic writing pad shaped in an elongated shape) on the palm side over substantially the entire length of the finger portion.

As a result, each of the fingers f1 to f5 changes from the contracted state shown in FIG. 11(a) to the state shown in FIG. 11(b) by injecting air into the hollow portion through the main passage portion p1.
In other words, the side on which the thin plate-like body v is not provided is more susceptible to expansion due to air pressure than the side on which the thin plate-like body v is provided, and the tip surfaces of each of the finger portions f1 to f5 also expand, so that each of the finger portions f1 to f5 curves in an arch shape toward the side on which the thin plate-like body v is not provided.
As air flows further into the hollow portion from the state shown in FIG. 11(b), each finger portion f1 to f5 further curves in an arch shape, passes through the approximately L-shape shown in FIG. 11(c), and then curves into the approximately hook shape shown in FIG. 11(d) (reach- ing the closed state).

In this modification, air injection means such as an air compressor connected to the main passage portion p1 for injecting air into the hollow portion serves as the finger opening/closing means 2.
In addition, the air injection means can be configured, for example, as a small object loaded onto drone A or placed on the ground.
This allows the air injection operation for each of the fingers f1 to f5 to be controlled automatically (remotely) or manually.

In addition, the entire robot hand body 1 does not necessarily need to be made of a flexible material such as silicone. For example, the outer periphery of a mechanical robot hand constructed using a link mechanism or the like may be covered with a member made of a flexible material such as cloth to prevent damage to the object to be anchored K.

The range of motion of the entire arm unit 3 may be further expanded by, for example, configuring the top surface of the drone body A1 as a platform that can rotate 360 degrees, or providing a configuration at the connection portion between the first arm unit 31 and the second arm unit 32 that allows the second arm unit 32 to rotate 360 degrees.

A drone W robot hand device 1 robot hand body 2 finger opening/closing means 3 arm K mooring object Z1 work tool Z2 baggage

Claims (7)

The robot hand device is a drone in which a pair of robot hand devices are attached along the left-right direction ,
A drone having a built-in battery, a plurality of arms extending from the drone body, and a propeller attached to each of the arms;
The robot hand device includes a robot hand body simulating a human hand, a finger opening/closing means for causing each finger of the robot hand body to perform an opening/closing motion, and an arm extending from a base end of the robot hand body and having a plurality of joints formed therein;
the arm portion has a first arm portion extending in a vertical direction, a second arm portion extending in a front-rear direction, and a wrist portion provided at a tip of the second arm portion and connected to the robot hand body,
The robot hand body is entirely made of a soft material having elasticity ,
The drone is positioned forward of the front propeller by the second arm and the wrist. A robot hand device provided on the drone according to claim 1,
2. The robot hand device according to claim 1, wherein the finger opening and closing means is configured to be able to perform opening and closing operations independently for each of the fingers. the finger opening/closing means includes a rope member having one end fixed to the tip end side of each of the fingers and the other end extending to the base end side of each of the fingers, and a pulling means for pulling each of the rope members toward the base end side of each of the fingers,
3. The robot hand device according to claim 2, wherein each of the fingers is biased in a direction toward an open state by an elastic force of a soft material, and is configured to transition to a closed state by pulling each of the rope members by the pulling means. The pulling means includes a bobbin around which each of the rope members is wound, and a rotating means for rotating the bobbin in a direction in which each of the rope members is wound,
4. The robot hand device according to claim 3, wherein the rotation means is a motor whose driving can be controlled remotely. the finger opening/closing means has a housing in which the bobbin around which each of the rope members is wound and the rotating means are stored, and the rope members are pulled out to the outside,
The robot hand device according to claim 4 , wherein the housing is provided on the second arm. A robot hand device provided on the drone according to claim 1,
Each finger has a cavity therein,
The finger opening and closing means causes each of the fingers to perform opening and closing operations by expanding and contracting each of the fingers through the inflow and outflow of air into the cavity. A robot hand device provided on the drone according to claim 1,
A robot hand device, wherein the robot hand body is configured so that the palm can be rotated via the wrist portion around an axis corresponding to a direction in which the second arm portion extends.