Hand structure

Abstract

To provide a hand structure capable of controlling a dynamic object.SOLUTION: A hand 10 according to an embodiment of the present disclosure includes a base portion 11, a finger joint portion 12 provided at the base portion 11, a finger portion 13 swingable about the finger joint portion 12, and a shock absorber 14 coupled between the base portion 11 and the finger portion 13 to relieve rotational torque generated in the finger portion 13 in response to a swing of the finger portion 13 due to collision of a dynamic object. The plurality of finger portions 13 are provided for one base portion 11, and the shock absorber 14 is connected between at least one of the finger portions 13 and the base portion 11.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a hand structure.

Background Art

[0002] In recent years, research and development of robot hands that imitate the human hand have been carried out. For example, Patent Document 1 discloses a robot hand having a hand part and an arm part. The hand part corresponds to the part corresponding to the part from the human wrist forward. The arm part has a drive part composed of a plurality of motors and generates a driving force for driving each movable part of the hand part. In this robot hand, a wrist arrangement pulley group arranged coaxially and an arm part pulley group arranged coaxially are engaged with each other by gears or the like, and the driving force generated by the drive part is transmitted to each movable part of the hand part.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is conceivable to control a dynamic object using the fingers, hand, and arm of a robot hand. However, since the robot hand has a rigid structure, it may be destroyed by a collision with a dynamic object. In addition, the dynamic object may bounce back at the moment of colliding with the robot hand, making it difficult to control the object with the robot hand. On the other hand, if the robot hand is composed of a flexible material such as an elastic body, it becomes difficult to apply a force to the object or control it.

[0005] The present disclosure has been made in view of such problems, and an object thereof is to provide a hand structure capable of controlling a dynamic object.

Means for Solving the Problems

[0006] A hand structure according to one aspect of the present disclosure includes a base portion, a finger joint portion provided on the base portion, a finger portion swingable about the finger joint portion, and a buffer connected between the base portion and the finger portion to relieve the rotational torque generated in the finger portion in response to the swing of the finger portion due to the collision of a dynamic object.

Advantages of the Invention

[0007] According to the present disclosure, a hand structure capable of controlling a dynamic object can be provided.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are appropriately omitted and simplified. Also, in each drawing, the same elements are denoted by the same reference numerals, and redundant explanations are omitted as necessary.

[0010] The embodiment relates to a hand structure applied to a robot hand (hereinafter simply referred to as "hand"). In the following description, the "hand" means a part corresponding to a human hand, which is attached to the tip of the arm of a humanoid robot. Also, the "finger" of the hand means a part corresponding to a human finger, and the "palm" of the hand means a part corresponding to a human palm.

[0011] FIG. 1 is a diagram showing a schematic configuration of a hand 10 to which the hand structure according to the embodiment is applied. The hand 10 is applied to, for example, a humanoid robot capable of receiving, gripping, or hitting back a dynamic ball W1. Such a humanoid robot can perform an operation such as a basketball dribble of receiving a ball W1 flying toward the palm of the hand 10 with the hand 10 and hitting it out. Note that this humanoid robot is not limited to the ball W1 and can receive other moving objects.

[0012] As shown in FIG. 1, the hand 10 mainly includes a base 11, a finger joint part 12, a finger part 13, a shock absorber 14, and a wrist part 15. In the example shown in FIG. 1, as the finger part 13, five fingers, namely, a thumb 13a, an index finger 13b, a middle finger 13c, a ring finger 13d, and a little finger 13e, are provided. When it is not necessary to distinguish these fingers, they are collectively referred to as the finger part 13. FIG. 2 is an enlarged view of a part of the hand 10 in FIG. 1. FIG. 2 is a view of the ring finger 13d in FIG. 1 seen from the side.

[0013] The base 11 is a part corresponding to the "palm". Note that, unlike a human palm including a plurality of metacarpal bones, in the example shown in FIG. 1, the base 11 is composed of one member. However, the configuration of the base 11 is not limited to this and may include members corresponding to a plurality of metacarpal bones.

[0014] Referring to FIG. 2, the base 11 is a substantially plate-shaped member with parallel upper and lower surfaces. The upper surface of the base 11 corresponds to the back of a human hand, and the lower surface corresponds to the palm of a human hand. The base 11 is provided with a lower protruding portion 11a protruding from its lower surface and an upper protruding portion 11b protruding from its upper surface. Here, in FIG. 2, XYZ coordinates are applied, where the left-right direction is the X direction, the up-down direction is the Y direction, and the direction perpendicular to the paper surface is the Z direction. The upper and lower surfaces of the base 11 are parallel to the XZ plane. The lower protruding portion 11a extends in the -Y direction from the end of the base 11. The upper protruding portion 11b extends in the +Y direction from a position closer to the center than the position where the lower protruding portion 11a of the base 11 is provided.

[0015] Five lower protruding portions 11a are provided at a predetermined interval at the end of the base 11. A finger portion 13 is swingably connected to each of the lower protruding portions 11a via a finger joint portion 12. The finger joint portion 12 corresponds to the middle phalanx and proximal phalanx joint connecting the metacarpal bone and proximal phalanx in the palm of a human hand. The finger joint portion 12 is, for example, a hinge joint. The finger portion 13 pivots with respect to the base 11 about a hinge axis. Let the rotation center of this finger portion 13 be C1. Note that the finger joint portion 12 is not limited to a hinge joint that rotates about a single hinge axis. For example, the finger joint portion 12 may be a ball / socket joint having more degrees of freedom than a hinge joint.

[0016] Unlike a human finger composed of a plurality of phalanges such as the finger portion 13, the distal phalanx, the middle phalanx, and the proximal phalanx, in the example shown in FIG. 1, each finger portion 13 consists of one member. However, the configuration of the finger portion 13 is not limited to this, and it may include members corresponding to a plurality of phalanges.

[0017] The shock absorber 14 relaxes the rotational torque generated in the finger portion 13 in response to the swinging of the finger portion 13 due to the collision of the ball W1 with the finger portion 13. As the shock absorber 14, a shock absorber, a gas spring, a rotary damper, a spring, etc. can be used. Hereinafter, an example in which a shock absorber that absorbs shock by the reciprocating movement of a rod in a cylinder filled with hydraulic oil is used as the shock absorber 14 will be described.

[0018] The shock absorber 14 is connected between at least one of the plurality of finger portions 13 and the base portion 11. In the example shown in FIG. 1, shock absorbers 14 are respectively connected between the index finger 13b and the ring finger 13d and the base portion 11. On the other hand, the shock absorber 14 is not connected to the thumb 13a, the middle finger 13c, and the little finger 13e.

[0019] Specifically, upper protrusions 11b are respectively provided at positions on the upper surface of the base portion 11 corresponding to the index finger 13b and the ring finger 13d. One end of the shock absorber 14 is respectively connected to the upper protrusion 11b. The other end of the shock absorber 14 is respectively connected in the vicinity of the end portion where the shock absorber 14 is connected to the knuckle portion 12 of the index finger 13b and the ring finger 13d. Note that the stroke end of the reciprocating rod of the shock absorber 14 may be on either the finger portion 13 side or the base portion 11 side.

[0020] Here, referring to FIG. 2, the ring finger 13d will be described as a representative. As shown in FIG. 2, let the connection portion between one end of the shock absorber 14 and the upper protrusion 11b be C2, and the connection portion between the other end of the shock absorber 14 and the ring finger 13d be C3. The connection portion C3 is at a position separated from the rotation center C1 of the finger portion 13 by a distance L1 in the -X direction and a distance L2 in the +Y direction. The hand 10 according to the embodiment has a link mechanism including the shock absorber 14 and the rotation center C1 that rotatably connects the ring finger 13d and the base portion 11.

[0021] The ball W1 flies from the palm side of the hand 10. In the example of FIG. 1, the ball W1 is received by the index finger 13b and the ring finger 13d provided with the shock absorber 14. The ball W1 collides with the bellies of the index finger 13b and the ring finger 13d. As a result, a rotational torque about the rotation center C1 is generated in the index finger 13b and the ring finger 13d. The shock absorber 14 can absorb the impact applied in the axial direction according to the rotational torque by the reciprocating movement of the rod in the cylinder filled with hydraulic oil. Thereby, it is possible to prevent the dynamic ball W1 from bouncing back at the moment of colliding with the finger portion 13, and it becomes possible to receive the ball W1 with the hand 10.

[0022] Let the intersection angle between the straight line in the X direction passing through the connection part C3 and the straight line passing through the connection parts C2 and C3, that is, the extending direction of the shock absorber 14, be θ. The torque T applied to the rotation center C1 by the resistance force F exerted by the shock absorber 14 on the finger part 13 is calculated by the following formula. T = F (L1 × sin θ + L2 × cos θ) If the positions of the rotation center C1 and the connection parts C2 and C3 are such that T in the above formula does not become zero, the shock absorption effect by the shock absorber 14 can be exerted even if θ = 0° or θ = 90°.

[0023] After receiving the dynamic ball W1, the hand 10 can grip the ball W1 using the thumb 13a, middle finger 13c, and little finger 13e where the shock absorber 14 is not provided. When the humanoid robot is equipped with the left and right hands 10, it is also possible to sandwich and grip the ball W1 with both hands 10.

[0024] The wrist part 15 connects the hand 10 and a robot arm (not shown). The wrist part 15 is provided with a drive part such as a motor (not shown). The output shaft of the drive part is connected to a wrist joint provided on the wrist part 15, and generates a rotational driving force of the hand 10 around the wrist joint.

[0025] This drive part applies acceleration to the hand 10 in a state where the finger joint part 12 is rigid, and hits the ball W1. As an example, the drive part can apply acceleration to the hand 10 so that the shock absorber 14 reaches the maximum displacement that it can take. Specifically, the drive part applies acceleration to the hand 10 so that the rod of the shock absorber moves to the stroke end and stops. When the shock absorber 14 reaches the maximum displacement, the index finger 13b and the ring finger 13d can be regarded as rigid bodies. In this way, by applying a force to the ball W1 using the index finger 13b and the ring finger 13d that have become rigid bodies, a force can be applied to the ball W1 in an appropriate direction. Also, as another example, the hand 10 may be provided with a mechanism that can lock the finger joint part 12 at an arbitrary position. The finger joint part 12 may be locked to make the finger joint part 12 in a rigid state, and the drive part may apply acceleration to the hand 10.

[0026] In addition, it is preferable that a buffer material 16 is provided on the ventral surface of the finger portion 13 that contacts the ball W1. The buffer material 16 increases the frictional force and forms a state in which the ball W1 is more stably stationary. The buffer material 16 is not particularly limited, but a rubber sheet or a synthetic resin material can be used. Examples of the synthetic resin include polyethylene, polypropylene, polystyrene, polyurethane, and the like.

[0027] Here, referring to FIGS. 3 to 5, the hitting operation of the ball W1 by the hand 10 will be described. FIG. 3 shows a state in which the dynamic ball W1 is in contact with the index finger 13b and the ring finger 13d. The ball W1 flying from the -Y direction in FIG. 3 contacts the buffer material 16 provided on the ventral surfaces of the index finger 13b and the ring finger 13d. At this time, a force in the +Y direction is applied to the index finger 13b and the ring finger 13d. As a result, the index finger 13b and the ring finger 13d swing in the +Y direction about the rotation center C1.

[0028] FIG. 4 shows a state in which the impact of the ball W1 on the index finger 13b and the ring finger 13d is absorbed by the shock absorber 14. Forces are applied to the shock absorbers 14 respectively connected to the index finger 13b and the ring finger 13d that swing in the +Y direction about the rotation center C1 in the direction in which the shock absorbers 14 extend, that is, along the straight line passing through the connection portions C2 and C3. Due to this force, the rod moves toward the stroke end in the cylinder filled with the hydraulic oil. Thereby, the rotational torque generated in the finger portion in response to the swing of the finger portion due to the collision of the dynamic ball W1 can be alleviated.

[0029] As described above, in the hand 10 of the embodiment, from the time when the dynamic ball W1 first contacts the index finger 13b and the ring finger 13d until the ball W1 becomes stationary, there is a time during which the ball W1 remains in contact with the index finger 13b and the ring finger 13d. During this time, the ball W1 can be controlled.

[0030] When the ball W1 is in a stationary state, the hand 10 applies a force to the ball W1 in the direction opposite to the flying direction. Fig. 5 shows a state in which the hand 10 is rotationally driven around the wrist joint to hit the ball. First, the driving unit applies acceleration to the hand 10, moves the rod to the stroke end and stops it. Then, the driving unit can further drive the hand 10 in a state where the shock absorber 14 can be regarded as a rigid body, apply a force to the ball W1, and hit it.

[0031] By the operations shown in Figs. 3 to 5, after receiving the dynamic ball W1, the hand 10 can hit the ball W1 back. By repeating this operation, the humanoid robot equipped with the hand 10 can perform operations such as dribbling a basketball.

[0032] In the above description, the operation of hitting the ball W1 is performed with the index finger 13b and the ring finger 13d, but it is not limited to this. For example, after bringing the dynamic ball W1 to a stationary state, a force may be applied to the ball W1 by the other thumb 13a, middle finger 13c, and little finger 13e to hit the ball W1.

[0033] Note that after bringing the dynamic ball W1 to a stationary state by the operations shown in Figs. 3 and 4, the ball W1 may be gripped by the thumb 13a, middle finger 13c, and little finger 13e where the shock absorber 14 is not provided. Note that the thumb 13a, middle finger 13c, and little finger 13e can be transitioned to a state of gripping the ball W1 by a driving unit (not shown). When gripping the ball W1, the cushioning material 16 provided on the ventral side of the thumb 13a, middle finger 13c, and little finger 13e comes into contact with the ball W1. Thereby, it becomes possible to stably grip the ball W1.

[0034] The present disclosure is not limited to the above-described embodiments and can be appropriately modified without departing from the spirit thereof. In the above-described embodiments, the shock absorber 14 is connected to the index finger 13b and the ring finger 13d, but it is not limited thereto. The shock absorber 14 may be provided on any finger portion. Further, the shock absorber 14 only needs to be provided on at least one finger portion, and the number of shock absorbers 14 is not limited. In the above-described embodiments, the hand structure is applied to a humanoid robot, but it may also be applied to an industrial robot or the like.

Explanation of Signs

[0035] 10 Hand 11 Base 12 Finger Joint Portion 13 Finger Portion 14 Shock Absorber 15 Wrist 16 Cushioning Material 11a Lower Protrusion 11b Upper Protrusion 13a Thumb 13b Index Finger 13c Middle Finger 13d Ring Finger 13e Little Finger W1 Ball

Claims

1. a base, a finger joint portion provided on the base, a finger portion swingable about the finger joint portion, a shock absorber connected between the base and the finger portion, for alleviating the rotational torque generated in the finger portion in response to the swing of the finger portion due to the collision of a dynamic object, a wrist joint portion connected to the base, a driving portion for driving the base about the wrist joint portion, and having after the object contacting the finger portion comes to a stationary state, the driving portion applies an acceleration to the base in a state where the finger joint portion becomes rigid, to eject the object, a hand structure.

2. The finger joint portion is made rigid by applying an acceleration to the base so as to achieve the maximum displacement that the shock absorber can obtain, or by locking the finger joint portion at an arbitrary position, The hand structure according to Claim 1.

3. a plurality of the finger portions are provided for one base, the shock absorber is connected between at least one of the plurality of finger portions and the base, The hand structure according to Claim 1.

4. further comprising a driving portion for driving the finger portion with respect to the base, the plurality of finger portions include a finger portion to which the shock absorber is connected and a finger portion to which the shock absorber is not connected, the driving portion drives the finger portion to which the shock absorber is not connected to grip the object, The hand structure according to Claim 3.

5. further comprising a cushioning material provided on the ventral side of the finger portion, The hand structure according to Claim 1.

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