Robot Hand and Manipulator

Abstract

This robot hand comprises: a palm portion; a first finger extending from the palm portion to a distal side, and having a finger pad surface facing the central axis of the palm portion; and a second finger extending from the palm portion to the distal side, and having a finger pad surface facing the finger pad surface of the first finger with the central axis of the palm portion therebetween. The palm portion has a proximal joint that connects the second finger to the palm portion so as to be pivotally movable about a first axis. The first finger does not have freedom in bending and stretching directions, and the second finger comprises a proximal phalanx portion close to the palm portion, a distal phalanx portion on the distal side relative to the proximal phalanx portion, and a middle phalanx portion between the proximal phalanx portion and the distal phalanx portion. Furthermore, the second finger comprises a middle joint that connects the middle phalanx portion to the proximal phalanx portion so as to be bendable and stretchable about a second axis, and a distal joint that connects the distal phalanx portion to the middle phalanx portion so as to be bendable and stretchable about a third axis.

Description

Technical Field

[0001] The present disclosure relates to a robot hand and a manipulator.

Background Art

[0002] Robot hands equipped with parallel grippers and manipulators equipped with parallel grippers as end effectors are already known (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] According to a parallel gripper, the contact with an object often becomes line contact or point contact. Therefore, with a parallel gripper, the shape of the object that can be stably gripped is limited. For stable gripping of objects with various shapes, it is desirable to be able to control the position of the contact portion of the robot hand with respect to the object and the posture and angle of the robot hand itself or its fingers when approaching the object. However, there is a problem that it is necessary to increase the degrees of freedom of motion of the robot hand, which leads to an increase in the size of the robot hand, as well as a complication of the structure and an increase in weight.

[0005] It is desirable to provide a robot hand and a manipulator that can achieve both ensuring gripping stability and suppressing an increase in size.

[0006] The robotic hand according to an embodiment of the present disclosure includes a palm portion, a first finger that extends distally from the palm portion and has a finger pad surface facing the central axis of the palm portion, and a second finger that extends distally from the palm portion and has a finger pad surface facing the finger pad surface of the first finger with the central axis of the palm portion interposed therebetween. In this embodiment, the palm portion has a proximal joint that rotatably connects the second finger to the palm portion about a first axis. The first finger has no degree of freedom in the bending and extending directions, and the second finger includes a proximal phalanx close to the palm portion, a distal phalanx provided more distally than the proximal phalanx, and a middle phalanx provided between the proximal phalanx and the distal phalanx. Further, the second finger includes an intermediate joint that bendably and extendably connects the middle phalanx to the proximal phalanx about a second axis, and a distal joint that bendably and extendably connects the distal phalanx to the middle phalanx about a third axis.

[0007] The manipulator according to an embodiment of the present disclosure includes an operating arm having a proximal end portion and a distal end portion and extending axially from the proximal end portion toward the distal end portion, and a robotic hand connected to the distal end portion of the operating arm. The robotic hand includes a palm portion, a first finger that extends distally from the palm portion and has a finger pad surface facing the central axis of the palm portion, and a second finger that extends distally from the palm portion and has a finger pad surface facing the finger pad surface of the first finger with the central axis of the palm portion interposed therebetween. In this embodiment, the palm portion has a proximal joint that rotatably connects the second finger to the palm portion about a first axis. The first finger has no degree of freedom in the bending and extending directions, and the second finger includes a proximal phalanx close to the palm portion, a distal phalanx provided more distally than the proximal phalanx, and a middle phalanx provided between the proximal phalanx and the distal phalanx. Further, the second finger includes an intermediate joint that bendably and extendably connects the middle phalanx to the proximal phalanx about a second axis, and a distal joint that bendably and extendably connects the distal phalanx to the middle phalanx about a third axis.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below are specific examples of the present disclosure, and the technology according to the present disclosure is not limited to the following specific aspects. Also, the same applies to the arrangement, dimensions of each component, and dimensional ratios between components according to the present disclosure, and it is not limited to the examples shown in each figure.

[0010] The description will be made in the following order. 1. First Embodiment 1.1. Configuration of the Robot Hand 1.1.1. Overall Configuration 1.1.2. Configuration of the Control System 1.2. Basic Operations of the Robot Hand 1.3. Explanation by Flowchart 1.4. Various Operations of the Robot Hand 1.4.1. First Operation Mode (Parallel Orbit Gripping Mode on the Same Plane) 1.4.2. Second Operation Mode (Multi-Point Contact Gripping Mode) 1.4.3. Third Operation Mode 1.5. Function and Effect 1.6. Explanation of Modification Examples 1.6.1. First Modification Example 1.6.2. Second Modification Example 2. Second Embodiment 3. Summary

[0011] <1. First Embodiment> [1.1. Structure of the Robot Hand] (1.1.1. Overall Structure) FIG. 1 is a perspective view showing the appearance of a robot hand H according to a first embodiment of the present disclosure.

[0012] FIG. 2 is an explanatory view showing the dimensions of each part of the robot hand H according to the present embodiment. FIG. 2(a) shows the state of the second finger 3 being slightly bent, Robot hand looking at H from a direction perpendicular to the frontal plane including the central axis Ax0 of the palm part 1. FIG. 2(b) shows the state of the robot hand H with the second finger 3 extended, looking from a direction perpendicular to the frontal plane (upper part) and a direction perpendicular to the horizontal plane (lower part).

[0013] The robot hand H is attached to the distal end of the operating arm A and constitutes the effector of the manipulator. In the present embodiment, the manipulator has a serial configuration and includes the operating arm A and the robot hand H. The operating arm A has a proximal end and a distal end, and has a shape that is long in the axial direction from the proximal end toward the distal end. The proximal end of the operating arm A can be attached to any robot body. The robot hand H is connected to the distal end of the operating arm A. In the present embodiment, the robot hand H includes a wrist portion 5, and can rotate about an axis parallel or perpendicular to the longitudinal axis of the operating arm A by the articulation of this wrist portion 5. In the following description, the side that is away from the proximal end of the operating arm A toward the fingertip of the robot hand H is defined as the distal side, and conversely, the side that approaches the proximal end of the operating arm A from the fingertip of the robot hand H is defined as the proximal side.

[0014] The robot hand H is roughly divided into a palm portion 1, a first finger 2, and a second finger 3.

[0015] The palm portion 1 is a pedestal portion that supports the fingers of the robot hand H, that is, the first finger 2 and the second finger 3 described below, and defines the shortest separation distance between the base of the first finger 2 and the base of the second finger 3. In the present embodiment, the shortest separation distance refers to the distance formed between the base of the first finger 2 and the base of the second finger 3 in a state where the second finger 3 is extended parallel to the central axis Ax0 of the palm portion 1 (Fig. 2(b)). The palm portion 1 is connected to the wrist portion 5 on the proximal side, and has a surface (hereinafter referred to as the "distal surface") 11 that faces the fingertip on the distal side.

[0016] The first finger 2 extends distally from the palm portion 1 and has a finger pad surface 21 that faces the central axis Ax0 of the palm portion 1. In the present embodiment, the central axis Ax0 of the palm portion 1 coincides with the longitudinal axis of the operating arm A and passes through the distal surface 11.

[0017] The second finger 3 extends distally from the palm portion 1 and has fingertip surfaces 31a, 31b that face the fingertip surface 21 of the first finger 2 with the central axis Ax0 of the palm portion 1 therebetween. The fingertip surface 21 of the first finger 2 and the fingertip surfaces 31a, 31b of the second finger 3 serve as contact surfaces with respect to an object (hereinafter referred to as “target object”) to be grasped by the robot hand H. That is, when grasping, the robot hand H contacts the target object with these fingertip surfaces 21, 31a, 31b and applies a grasping force thereto. In the present embodiment, the first finger 2 has a fingertip surface 21 over the entire length from the fingertip portion to the base portion. On the other hand, the second finger 3 has a fingertip surface 31a at the distal phalanx portion l3 and a fingertip surface 31b at the middle phalanx portion l2.

[0018] The robot hand H has four degrees of freedom that contribute to the grasping of the target object, in addition to the degrees of freedom provided by the wrist portion 5.

[0019] The robot hand H includes a proximal joint j1 that rotatably connects the second finger 3 to the palm portion 1 about a first axis (which may be referred to as the first pitch axis) Ax1 with respect to the palm portion 1. The second finger 3 includes a proximal phalanx portion (which may be referred to as the first or proximal link) l1 close to the palm portion 1, a distal phalanx portion (which may be referred to as the third or distal link) l3 provided more distally than the proximal phalanx portion l1, and a middle phalanx portion (which may be referred to as the second or middle link) l2 provided between the proximal phalanx portion l1 and the distal phalanx portion l3, and also includes two joints j2, j3. One is an intermediate joint j2 that bends and extends the middle phalanx portion l2 with respect to the proximal phalanx portion l1 about a second axis (which may be referred to as the second pitch axis) Ax2, and the other is a distal joint j3 that bends and extends the distal phalanx portion l3 with respect to the middle phalanx portion l2 about a third axis (which may be referred to as the third pitch axis) Ax3. In the present embodiment, the first, second, and third axes Ax1, Ax2, A3 are parallel to each other, and the first axis Ax1 and the central axis Ax0 of the palm portion 1 are in a three-dimensional intersecting positional relationship with each other.

[0020] On the other hand, the first finger 2 has no degrees of freedom in the bending and stretching directions, and can pivot about a fourth axis (which may be called the yaw axis y with respect to the pitch axis p) Ax4 that coincides with or is parallel to the central axis Ax0 of the palm part 1 with respect to the palm part 1. The fourth axis Ax4 is in a position where it intersects the first axis Ax1 three-dimensionally, and in the present embodiment, it coincides with the central axis Ax0 of the palm part 1. The first finger 2 can be made rigid in the bending and stretching directions and have a configuration with no degrees of freedom, for example, by forming the entire finger from the fingertip to the base with a single link member.

[0021] Thus, the robotic hand H has the following four degrees of freedom that contribute to grasping an object. The first is one degree of freedom (degree of freedom in the pivoting direction about the fourth axis Ax4) imparted to the first finger 3 by the palm part 1, the second is one degree of freedom (degree of freedom in the rotational direction about the first axis Ax1) imparted to the second finger 3 by the proximal joint j1 of the palm part 1, and the third and fourth are two degrees of freedom (degrees of freedom in the bending and stretching directions about the second axis Ax2 and the third axis Ax3) that the second finger 3 itself has at the intermediate joint j2 and the distal joint j3.

[0022] In the present embodiment, the first finger 2 has a narrower finger width than the second finger 3, and as shown in Fig. 2(b), particularly when comparing the fingertip part of the first finger 2 and the distal phalanx part l3 of the second finger 3, the fingertip part (finger width D1) of the first finger 2 is narrower than the distal phalanx part l3 (finger width D2) of the second finger 3.

[0023] Furthermore, as shown in the upper parts of FIGS. 2(a) and 2(b), the first finger 2 has a shape in which the fingertip surface 21 gradually moves away from the central axis Ax0 of the palm part 1 as it approaches the tip from the base. That is, the fingertip surface 21 of the first finger 2 forms a concave shape with an increasing depth in a direction away from the central axis Ax0 of the palm part 1, with the straight line connecting the base and the tip as the horizontal reference. In a cross-section by a horizontal plane, the shape outlined by the edge of the fingertip surface 21 of the first finger 2 may be planar or curved. And, as shown in FIG. 2(a), the first finger 2 has an initial opening angle α which is the angle formed between the straight line connecting the base and the tip of the fingertip surface 21 and a reference line parallel to the central axis Ax0 of the palm part 1. The initial opening angle α is preferably in the range of 10 degrees to 60 degrees, and in this embodiment, it is 30 degrees. By having the first finger 2 with the initial opening angle α, it becomes easier to adjust the angle of the fingertip surface 21 of the first finger 2 with respect to the object during gripping.

[0024] In this embodiment, in addition to the above, as degrees of freedom provided by the wrist part 5, the following two degrees of freedom are set. One degree of freedom in the rotational direction about the central axis of the palm part 1 (i.e., the yaw axis y), and one degree of freedom in the rocking direction about an axis parallel to the first axis Ax1 (i.e., the pitch axis p). Thereby, the robot hand H can apply torsion to the operating arm A by the wrist part 5, or rock the entire robot hand H starting from the wrist part 5. Instead of or in addition to the degree of freedom about the pitch axis p, it is also possible to provide a degree of freedom in the rocking direction about a roll axis r perpendicular to the central axis Ax0 of the palm part 1.

[0025] The robot hand H is provided with actuators in the number corresponding to the degrees of freedom at the wrist portion 5, and is also provided with actuators at each of the palm portion 1 (including the proximal joint j1), the intermediate joint j2 and the distal joint j3 of the second finger 3. In the present embodiment, the proximal joint j1 has a larger diameter than either the intermediate joint j2 or the distal joint j3, and as the actuator incorporated in the proximal joint j1, it is possible to employ an actuator with a larger output than those incorporated in the intermediate joint j2 and the distal joint j3. For example, an electric motor can be exemplified as an applicable actuator, and an electric motor capable of outputting higher torque than the other intermediate joint j2 and distal joint j3 can be employed for the proximal joint j1.

[0026] In the present embodiment, a control unit 101 configured as an electronic control device is provided, and by controlling the operation of the actuator by the control unit 101, it is possible to control the posture and operation of the robot hand H when gripping an object. The control system including the control unit 101 will be described in more detail later.

[0027] FIG. 3 is a diagram showing the dimensions of each part of the robot hand H according to the present embodiment while changing the posture of the second finger 3. FIG. 3(a) shows a state where the proximal joint j1 is at the intermediate opening degree, the intermediate joint j2 is extended, and the distal joint j3 is bent. FIG. 3(b) shows a state where the proximal joint j1 is at the maximum opening degree, the angle formed by the proximal phalanx l1 of the second finger 3 with respect to the first finger 2 is maximally widened, the intermediate joint j2 is bent, and the distal joint j3 is extended. FIG. 3(c) shows a state where the proximal joint j1 is at the minimum opening degree, the angle formed by the proximal phalanx l1 of the second finger 3 with respect to the first finger 2 is minimized, and both the intermediate joint j2 and the distal joint j3 are extended. In FIGS. 3(a) and 3(b), the fingertip of the first finger 2 and the distal phalanx l3 of the second finger 3 are on the same plane. In FIG. 3(c), the straight line connecting the base and the tip of the finger pad surface 21 of the first finger 2 forms an angle equal to the initial opening angle α with the straight line parallel to the finger pad surfaces 31a and 31b of the middle phalanx l2 and the distal phalanx l3 of the second finger 3. In the present embodiment, when the tip of the fingertip of the first finger 2 and the tip of the distal phalanx l3 of the second finger 3 are on the same plane, it is considered that "the fingertip of the first finger 2 and the distal phalanx l3 of the second finger 3 are on the same plane". As a reference part for determining whether they are on the same plane, it is also possible to adopt the part that first contacts the object during gripping instead of the tip of the fingertip or the distal phalanx l3. With reference to FIG. 3, the configuration of the robot hand H will be further described.

[0028] The dimensions shown in FIG. 3 are as follows. L1 is the length in the direction along the fingertip surface of the proximal phalanx l1 from the center of the proximal joint j1 to the center of the intermediate joint j2. L2 is the length in the direction along the fingertip surface 31b of the middle phalanx l2 from the center of the intermediate joint j2 to the center of the distal joint j3. L3 is the length in the direction along the fingertip surface 31a of the distal phalanx l3 from the center of the distal joint j3 to the tip of the second finger 3, that is, the tip of the distal phalanx l3 of the second finger 3. L4 is the length of the first finger 2, which is defined in a direction parallel to the central axis Ax0 (FIG. 2(b)) of the palm portion 1. L5 is the distance formed between the center of the distal joint j3 and the tip of the first finger 2, that is, the tip of the fingertip portion of the first finger 2, with both the intermediate joint j2 and the distal joint j3 of the second finger 3 extended, and is an index of the width of the distal surface 11 of the palm portion 1. L6 is the distance formed between the tip of the first finger 2 and the tip of the second finger 3 in the state shown in FIG. 3(a), and corresponds to the maximum lateral dimension of the object that can be grasped by the first operation mode (parallel track grasping mode on the same plane) described later. L7 is the height from the tip of the first finger 2 to the palm portion 1 or its distal surface 11, and corresponds to the maximum height dimension of the object that can be grasped by the first operation mode. L8 is the diameter of the distal joint j3, and L9 is the diameter of the wrist portion. Here, among the dimensions L3, L7, and L8, the relationship shown in the following formula (1) holds as a condition for enabling the operation by the first operation mode. In the present embodiment, the proximal joint j1 is included in the palm portion 1, and thereby, the distal surface 11 of the palm portion 1 extends from a portion adjacent to the base of the first finger 2 to a part of the side surface of the proximal joint j1. In the present embodiment, the lengths L1, L2, and L3 of the respective phalanges l1, l2, and l3 are equal to each other (the following formula (2)). Further, in the present embodiment, the distal phalanx l3 of the second finger 3 has a tapered shape in which the thickness decreases toward the distal side. L3 + L8 / 2 ≦ L7 …(1) L1 = L2 = L3 …(2)

[0029] (1.1.2) Configuration of the control system FIG. 4 is a schematic diagram schematically showing the configuration of the control system S of the robot hand H according to the present embodiment.

[0030] The control system S is roughly divided into a control unit 101 (Fig. 1), various sensors 201 to 204, and various actuators ACT. As described above, the actuator ACT includes an electric motor provided in a movable part such as a joint of the robot hand H.

[0031] The sensors 201 to 204 are installed at different parts of the robot hand H and are used to grasp the positional relationship between the robot hand H and the object or to detect the contact of the robot hand H with the object.

[0032] The sensor 201 is provided on the palm part 1 and can detect the position of the object with respect to the palm part 1 or detect the contact of the object with the distal surface 11 of the palm part 1. Examples of sensors applicable to the sensor 201 include a tactile sensor and a proximity sensor, and it can also be replaced with a vision sensor or a camera.

[0033] The sensor 202 is provided on the first finger 2 and detects the contact of the object with the finger pad surface 21 of the first finger 2. Examples of sensors applicable to the sensor 202 include a tactile sensor and a proximity sensor.

[0034] The sensor 203 is provided on the middle phalanx l2 of the second finger 3 and detects the contact of the object with the finger pad surface 31b of the middle phalanx l2. Examples of sensors applicable to the sensor 203 include a tactile sensor and a proximity sensor.

[0035] The sensor 204 is provided on the distal phalanx l3 of the second finger 3 and detects the contact of the object with the finger pad surface 31a of the distal phalanx l3. Examples of sensors applicable to the sensor 204 include a tactile sensor and a proximity sensor.

[0036] In this embodiment, the sensor 204 provided in the distal phalanx portion l3 has a higher resolution than the sensor provided in the middle phalanx portion l2, while having a lower load range. This is due to the difference in the use of the sensor output when gripping an object. In the first operation mode (parallel orbit gripping mode on the same plane), which will be described later, a relatively small and light object is targeted for gripping, and the gripping force of the robot hand H is controlled using the high-resolution sensor 204 provided in the distal phalanx portion l3. On the other hand, in the second operation mode (multi-point contact gripping mode), a relatively large and heavy object is targeted for gripping, and the gripping force of the robot hand H is controlled using the high-load range sensor 203 provided in the middle phalanx portion l2. Thus, in this embodiment, depending on the size and shape of the object, etc., the sensor used for controlling the gripping force is switched between the sensors 203 and 204.

[0037] In addition to the middle phalanx portion l2 and the distal phalanx portion l3 of the second finger 3, it is also possible to install a sensor in the proximal phalanx portion l1 and use it for controlling the actuator ACT when gripping an object.

[0038] The control unit 101 is configured, as an example, as a microcomputer including a central processing unit (CPU) equipped with a processor, etc., various storage devices such as a ROM and a RAM, and an input / output interface, etc. It inputs the detection signals from the sensors 201 to 204, and based on the input sensor signals, executes calculations according to the commands of a predetermined program. Then, the command signal obtained as a result of the calculation is output to the drive unit of the actuator ACT.

[0039] In this embodiment, the control unit 101 discriminates an object and selects an operation mode between a first operation mode, i.e., a parallel track gripping mode on the same plane, and a second operation mode, i.e., a multi-point contact gripping mode, according to the discriminated object. Then, the control unit 101 controls the operation of the robot hand H when gripping the object according to the selected operation mode. Here, the second operation mode is selected when gripping a relatively large object, and is characterized as an operation mode in which the contact areas of the fingertip surfaces 21, 31a, and 31b of the first finger 2 and the second fingers 3 with respect to the object are wider than those in the first operation mode. In this embodiment, the switching of the contact area is achieved by varying the parts of the palm part 1, the first finger 2, and the second fingers 3 that come into contact with the object during gripping. Generally speaking, the control unit 101 includes an object discrimination unit 111, an operation mode selection unit 121, and a hand control unit 131.

[0040] The object discrimination unit 111 discriminates an object. In this embodiment, the discrimination of the object includes the discrimination of the size, shape, material, etc. of the object. The discrimination of the object can be achieved by creating a list of these pieces of information regarding the object in advance and storing it in the control unit 101, or by installing a camera capable of photographing the object and discriminating the type or attributes of the object based on the image data obtained by this camera.

[0041] The operation mode selection unit 121 selects an operation mode between the first operation mode and the second operation mode according to the object discriminated by the object discrimination unit 111.

[0042] Specifically, the operation mode selection unit 121 compares the dimension of the object with a preset reference dimension, and selects the first operation mode when the dimension of the object is smaller than the reference dimension. On the other hand, the operation mode selection unit 121 selects the second operation mode when the dimension of the object is larger than the reference dimension. As described above, the second operation mode is an operation mode in which the contact areas of the fingertip surfaces 21, 31a, and 31b of the robot hand H with respect to the object are wider than those in the first operation mode.

[0043] The reference dimension is, for example, the maximum value that the distance between each of these end portions can take in a state where the fingertip portion of the first finger 2 and the distal phalanx portion l3 of the second finger 3 are on the same plane perpendicular to the central axis Ax0 of the palm portion 1. The reference dimension in this case is given as the dimension indicated by reference numeral L6 in FIG. 3(a).

[0044] Alternatively, the reference dimension may be a distance defined in a direction parallel to the central axis Ax0 of the palm portion 1 between the tip of the first finger 2 and the distal surface 11 of the palm portion 1. The reference dimension in this case is given as the dimension indicated by reference numeral L7 in FIGS. 3(a) and (b).

[0045] In the present embodiment, the operation mode selection unit 121 selects the first operation mode when the lateral width dimension of the object is smaller than the first reference dimension L6 and the height dimension of the object is smaller than the second reference dimension L7, and selects the second operation mode when the lateral width dimension of the object is larger than the first reference dimension L6 or, otherwise, the height dimension of the object is larger than the second reference dimension L7.

[0046] The hand control unit 131 controls the operation of the robot hand H when gripping the object according to the operation mode selected by the operation mode selection unit 121.

[0047] [1.2. Basic Operations of the Robot Hand] As described above, the first operation mode and the second operation mode are distinguished in terms of the contact area formed between the object and the robot hand H during gripping. The first operation mode is characterized as an operation mode with a relatively small contact area, and the second operation mode is characterized as an operation mode with a relatively large contact area. Further, in the present embodiment, the magnitude of the gripping force exerted by the robot hand H on the object is made different between the first operation mode and the second operation mode, and accordingly, the positions and characteristics of the sensors 203 and 204 used for controlling the gripping force, that is, the resolution and load range of the sensors are switched.

[0048] FIG. 8 shows an example of the operation of the robot hand H when gripping a cylindrical or spherical object T11 in the first operation mode. Taking FIG. 8 as an example, in the first operation mode, the robot hand H is appropriately positioned with respect to the object T11. Specifically, after arranging the fingertip portion of the first finger 2 and the distal phalanx portion l3 of the second finger 3 approximately at the height of the center of gravity of the object T11, the fingertip portion of the first finger 2 is brought closer to the object, and its fingertip surface 21 is brought into contact with the side surface at the height of the center of gravity of the object. In the first operation mode, this contact by the first finger 2 is the first contact of the robot hand H with the object. At the time of this contact, the distal surface 11 of the palm portion 1 is not in contact with the object, and there is a space between the object and the palm portion 1. Then, the distal phalanx portion l3 of the second finger 3 is brought closer to the object T11, and its fingertip surface 31a is brought into contact with the side surface of the object that is opposite to the side surface in contact with the fingertip surface 21 of the fingertip portion of the first finger 2. Here, in the first operation mode, when bringing the distal phalanx portion l3 of the second finger 3 closer to the object T11, the distal joint j3 is appropriately actuated so that the distal phalanx portion l3 of the second finger 3 moves while maintaining its tip on the same plane P. In other words, in the first operation mode, while bringing the distal phalanx portion l3 of the second finger 3 closer to the object T11, its tip and the tip of the fingertip portion of the first finger 2 are always on the same plane P. After the fingertip surface 31a of the distal phalanx portion l3 of the second finger 3 is brought into contact with the object, a gripping force by the robot hand H is applied to the object to grip the object.

[0049] FIG. 15 shows an example of the operation of the robot hand H when gripping cylindrical or spherical objects (especially those with a large diameter or weight) T71 and T72 in the second operation mode. Taking FIG. 15 as an example, in the second operation mode, the robot hand H is brought close to the objects T71 and T72, and the distal surface 11 of the palm part 1 is brought into contact with the objects T71 and T72. In the second operation mode, this contact by the palm part 1 is the first contact of the robot hand H with the objects T71 and T72. Then, the tip part of the first finger 2 is brought close to the objects T71 and T72, and its finger belly surface 21 is brought into contact with the side surface generally at the height of the center of gravity of the objects T71 and T72. After the contact by the first finger 2, the second finger 3 is brought close to the objects T71 and T72, and the finger belly surface 31b of the middle phalanx l2 and the finger belly surface 31a of the distal phalanx l3 are brought into contact with the side surfaces of the objects T71 and T72 in this order. Here, in the second operation mode, not only the tip part of the first finger 2 and the distal phalanx l3 of the second finger 3, but also the palm part 1 and the middle phalanx l2 of the second finger 3 are involved in gripping or forming the gripping force of the objects T71 and T72, so that multi-point contact with the objects T71 and T72 is realized and the contact area is increased. After the finger belly surfaces 31a and 31b of the middle phalanx l2 and the distal phalanx l3 of the second finger 3 are brought into contact with the objects T71 and T72, a gripping force by the robot hand H is applied to the objects to grip the objects.

[0050] The above is the basic operation performed by the robot hand H when gripping an object. In this embodiment, in addition to the above, the following two are adopted as derivative modes classified into the first operation mode or the second operation mode.

[0051] One is a derivative mode when gripping an object whose side surface has an inclination or is in a tapered shape, and is classified into the first operation mode. Specifically, prior to bringing the finger belly surface 31a of the distal phalanx l3 of the second finger 3 into contact with the object, the first finger 2 is rotated about the fourth axis Ax4, and the orientation of the finger belly surface 21 of the first finger 2 is brought close to the orientation of the side surface of the object to align the inclination of the finger belly surface 21 with the inclination of the side surface of the object. FIG. 13 shows an example of this derivative mode, showing the operation of the robot hand H when gripping a high inclined surface object T51 in the first operation mode.

[0052] The other is a derivative mode when gripping an object with a narrow width W or a low height H but a large moment load (such as a handle of a frying pan or a long rod at the tip), and is classified into the second operation mode. Specifically, after bringing the distal surface 11 of the palm part 1 into contact with the object and further bringing the fingertip surface 21 of the first finger 2 into contact, the proximal joint j1 is rotated and the intermediate joint j2 and the distal joint j3 are bent. In this way, the second finger 3 is closed to surround the object with the second finger 3 and apply a gripping force. This is a gripping form generally known as a form closure. FIG. 18 shows the operation of the robot hand H when gripping a cylindrical object (especially one with a large moment load) T101 as an example of this derivative mode.

[0053] [1.3. Explanation by flowchart] FIG. 5 is a flowchart showing the overall flow of the gripping operation performed by the robot hand H according to the first embodiment of the present disclosure. FIG. 6 is a flowchart showing the specific content of the gripping operation when the first operation mode (parallel track gripping mode on the same plane) according to the present embodiment is selected, and FIG. 7 is a flowchart showing the specific content of the gripping operation when the second operation mode (multi-point contact gripping mode) according to the present embodiment is selected. FIG. 5 to 7 The operations shown in FIG. are controlled by the control unit 101 and are executed every time an object (target object) to be gripped is specified.

[0054] In S101, the object 101 is recognized.

[0055] In S102, the dimensions of the object 101 are acquired. In the present embodiment, the width dimension W of the part of the object where the gripping force by the robot hand H acts and the height dimension H of the object are acquired.

[0056] In S103, it is determined whether the load applied from the object during gripping is within the range of the standard load. If the load is within the range of the standard load, the process proceeds to S104; if not, the process proceeds to S107. The standard load can be defined as the weight of the object or the moment load applied from the object to the robot hand H.

[0057] In S104, it is determined whether the lateral dimension W of the object is less than or equal to the first reference dimension L6. If the lateral dimension W is less than or equal to the first reference dimension L6, the process proceeds to S105; if it exceeds the first reference dimension L6, the process proceeds to S107.

[0058] In S105, it is determined whether the height dimension H of the object is less than or equal to the second reference dimension L7. If the height dimension H is less than or equal to the second reference dimension L7, the process proceeds to S106; if it exceeds the second reference dimension L7, the process proceeds to S107.

[0059] In S106, the first operation mode is selected as the operation mode of the robot hand H.

[0060] In S107, the second operation mode is selected as the operation mode of the robot hand H.

[0061] When the first operation mode is selected, Figure 6 the process moves to the flowchart shown in, and the object is gripped in the first operation mode.

[0062] In S201, the angle of the fingertip of the first finger 2 is adjusted so that the fingertip of the first finger 2 is generally aligned with the height of the center of gravity of the object and the finger contact surface 21 of the first finger 2 is generally parallel to the side surface of the object. This adjustment is mainly possible by the movement of the wrist part 5.

[0063] In S202, the fingertip of the first finger 2 is brought closer to the object, and the finger contact surface 21 is brought into contact with the side surface at the height of the center of gravity of the object.

[0064] In S203, the angle of the side surface of the object on the side opposite to the side surface in contact with the finger contact surface 21 of the fingertip of the first finger 2 is measured.

[0065] In S204, the angle of the distal phalanx l3 of the second finger 3 is adjusted to approach the measured angle. This adjustment is achieved by appropriately operating the proximal joint j1, the intermediate joint j2, and the distal joint j3. Then, while moving the distal phalanx l3 to maintain the adjusted angle of the distal phalanx l3, the distal phalanx l3 of the second finger 3 is brought closer to the object. Here, if necessary, the first finger 2 can be relatively rotated about the fourth axis Ax4 to assist the operation of maintaining the angle of the distal phalanx l3.

[0066] In S205, the fingertip surface 31a of the distal phalanx l3 of the second finger 3 is brought into contact with the opposite side surface of the object.

[0067] In S206, a gripping force by the robot hand H is applied to the object to complete the gripping.

[0068] When the second operation mode is selected, Figure 7 the process proceeds to the flowchart shown in, and the object is gripped in the second operation mode.

[0069] In S301, the second finger 3 is rotated outward about the first axis Ax1 by the operation of the proximal joint l1, and the opening formed between the first finger 2 and the second finger 3 is widened to an extent that can receive the object to be gripped.

[0070] In S302, the robot hand H is brought closer to the object, and the distal surface 11 of the palm part 1 is brought into contact with the object.

[0071] In the subsequent S202 and later, the same operations as S202 to S206 in the first operation mode are performed. That is, the fingertip of the first finger 2 is brought close to the object, and its finger ventral surface 21 is brought into contact with the side surface at the height of the center of gravity of the object (S202). The angle of the side surface of the object on the side opposite to the side surface in contact with the finger ventral surface 21 of the fingertip of the first finger 2 is measured (S203). The angle of the distal phalanx l3 of the second finger 3 is adjusted to approach the measured angle, and while maintaining the adjusted angle of the distal phalanx l3, the distal phalanx l3 of the second finger 3 is brought close to the object (S204). The finger ventral surface 31a is brought into contact with the opposite side surface of the object (S205). Further, a gripping force against the object is formed (S206) to complete the gripping.

[0072] [1.4. Various operations of the robotic hand] Specific gripping of an object by the first operation mode and the second operation mode is exemplified below.

[0073] (1.4.1. First operation mode (parallel track gripping mode on the same plane)) FIG. 8 shows an example of the operation in the first operation mode when gripping a cylindrical or spherical object T11. The finger ventral surface 21 of the fingertip of the first finger 2 is brought into contact with the side surface near the height of the center of gravity of the object, the distal phalanx l3 of the second finger 3 is brought close to the object T11 along the track on the same plane P, and its finger ventral surface 31a is brought into contact with the side surface opposite to the finger ventral surface 21.

[0074] FIG. 9 shows examples of the operation in the first operation mode when gripping (a) a prismatic object T21, (b) a small object T22 with a small side dimension, and (c) a thin object T23 with a small thickness. The operation of the robotic hand H in this case is the same as that shown in FIG. 8. However, particularly when gripping the small object T22 and the thin object T23 shown in FIGS. 9(b) and (c), it is possible to keep the state of the wrist 5 fixed, and the manipulation load of the entire manipulator including the operation arm A can be kept low.

[0075] Figure 10 shows an example of the operation in the first operation mode when gripping an inclined surface object (for example, a triangular prism or a square pyramid with a low height) T31 having an inclination on the side surface and an object (for example, a cup-like object) T32 having a tapered side surface. The operation of the robot hand H in this case is characterized in that the rotational angle imparted by the distal joint j3 is large when the distal joint l3 of the third finger 3 approaches the objects T31 and T32.

[0076] Figure 11 shows an example of the operation in the first operation mode when gripping, as a shell-shaped object, (a) a cylindrical object T41, (b) a deep dish-shaped object T42, and (c) a bowl-shaped object T43 having a tapered shape on the side surface. Figure 12 shows an example of the operation in the first operation mode when gripping, as another shell-shaped object, a shallow (i.e., not deep) dish-shaped object T44. In the present embodiment, the shell shape refers to a shape formed by thinly shaping a cylinder, an inverted cone, a truncated inverted cone, a hemisphere, etc., and for example, the shapes of a cup, various dishes of different sizes, a small bowl, and a bowl correspond to this. With respect to the objects T41, T42, T43, and T44 having a shell shape, the finger pad surface 21 of the fingertip portion of the first finger 2 is brought into contact with the inner surface of the shell near the upper edge at an adjusted angle, and the finger pad surface 31a of the distal joint l3 of the second finger 3 is brought into contact with the outer surface of the shell near the height of the center of gravity of the object, so as to Edge grip by pinching the object.

[0077] Figure 13 shows an example of the operation in the first operation mode when gripping a high inclined surface object (for example, a triangular prism in which two sides of the bottom surface are longer than the other side or a high square pyramid) T51. The robot hand H is laid down and approached from the side with respect to the object T51. By the relative rotation about the fourth axis Ax4 of the first finger 2, the angle of the fingertip portion of the first finger 2 is adjusted, and after the finger pad surface 21 is brought into contact with the side surface of the object T51, the distal joint l3 of the second finger 3 is brought close to the opposite side surface near the height of the center of gravity of the object T51 while maintaining the angle of the distal joint l3 adjusted by the operation of the distal joint j3, and the finger pad surface 31a is brought into contact therewith.

[0078] Figure 14 shows an example of the operation in the first operation mode when gripping a thin object T61 with a small thickness. The operation of the robot hand H in this case is the same as that shown in Figure 13. When gripping, the robot hand H is laid down and approached from the side to the object T61. In the operation after the fingertip ventral surface 21 of the first finger 2 contacts the side surface of the object, when the distal phalanx l3 of the second finger 3 approaches the side surface on the opposite side of the object T61, it is characterized in that the side surface or side edge of the fingertip of the first finger 2 and the side surface or side edge of the distal phalanx l3 of the second finger 3 maintain the same-plane trajectory.

[0079] (1.4.2. Second operation mode (multi-point contact gripping mode)) Figure 15 shows an example of the operation in the second operation mode when gripping a cylindrical or spherical object (especially one with a large diameter or weight) T71, T72. The fingers of the robot hand H are opened by the operation of the proximal joint j1 and approached to the objects T71, T72, and the distal surface 11 of the palm part 1 is brought into contact. Then, the fingertip ventral surface 21 of the first finger 2 is brought into contact with the side surfaces of the objects T71, T72, and the second finger 3 is brought into contact with the side surfaces on the opposite sides of the objects T71, T72 in the order of the ventral surface 31b of the middle phalanx l2 and the ventral surface 31a of the distal phalanx l3. At this time, it is more suitable to bring the fingertip ventral surface 21 of the first finger 2 and the ventral surface 31a of the distal phalanx l3 of the second finger 3 into contact closer to the height of the center of gravity of the objects T71, T72.

[0080] Figure 16 shows an example of the operation in the second operation mode when gripping a prismatic object (for example, a cuboid or cube with a particularly large height or thickness) T81. Figure 17 shows an example of the operation in the second operation mode when gripping an inclined surface object (for example, a triangular prism with two sides being particularly long compared to the other side or a quadrangular pyramid with a particularly large height) T91. The operation of the robot hand H in this case is the same as that shown in Figure 15.

[0081] FIG. 18 shows an example of the operation in the second operation mode when gripping an object T101 having a cylindrical or elongated shape (for example, a handle of a frying pan, etc., particularly one with a large moment load). The distal surface 11 of the palm portion 1 is brought into contact with the object T101, and further, after the fingertip surface 21 of the first finger 2 (in this case, the fingertip surface near the base of the first finger 2 is brought into contact), the proximal joint j1 is rotated, and the intermediate joint j2 and the distal joint j3 are bent so that the second finger 3 closes to surround the object T101.

[0082] FIG. 19 shows an example of the operation in the second operation mode when gripping an object T111 whose side surface is tapered. The operation of the robot hand H in this case is based on a different operation mode but is approximated to that shown in FIG. 13. The robot hand H is laid down and approached from the side with the angle of the fingertip of the first finger 2 adjusted by the operation of the wrist portion 5 with respect to the object T111. Then, after the distal surface 11 of the palm portion 1 is brought into contact with the object T111, the fingertip surface 21 of the first finger 2 is brought into contact with the side surface of the object T111, and further, by relatively rotating the first finger 2 about the fourth axis Ax4, the angle of the distal phalanx l3 of the second finger 3 is adjusted to match the inclination of the side surface of the object T111, and while maintaining the adjusted angle of the distal phalanx l3 with respect to the opposite side surface of the object T111, it is brought closer and the fingertip surface 31a is brought into contact.

[0083] (1.4.3. Third operation mode) In addition to the above, in this embodiment, a third operation mode is adopted in which the first finger 2 is spread in a plane perpendicular to the central axis Ax0 of the palm portion 1.

[0084] FIG. 20 shows an example of the state of the robot hand H in the third operation mode in which the first finger 2 is opened wide, for example, to the maximum opening width at which the angle formed by the direction in which the fingertip surface 21 of the first finger 2 faces and the directions in which the fingertip surfaces 31a, 31b of the second finger 3 face exceeds 90 degrees. By the third operation mode, the palm portion 1 can be opened wide, enabling it to correspond to applications using the entire fingertip surfaces 31a, 31b of the second finger 3.

[0085] FIG. 21 shows an example of utilization of gripping in the third operation mode. By arranging a pair of robot hands H symmetrically with respect to each other in a mirror image, it becomes possible to perform gripping with both hands using both arms, and it is possible to take an approach of supporting the object T121 on a wide plane or holding it by sandwiching it from both sides.

[0086] [1.5. Operational effects] In the case of a typical parallel gripper as an effector provided in a manipulator such as a robot arm, since the contact with the object often becomes line contact or point contact, the shape of the object that can be stably gripped is limited. For stable gripping of objects with various shapes, it is desirable to be able to control the position of the contact portion of the robot hand with respect to the object and the angle of the robot hand or its fingers when approaching the object. However, it is necessary to increase the degrees of freedom of motion of the robot hand, and there is a problem of causing an increase in the size of the robot hand, further, a complication of the structure and an increase in weight. And, the increase in the size of the robot hand induces a problem that the applicable uses are limited because it causes an increase in the load on the arm that supports the robot hand.

[0087] Here, by configuring the robot hand to have multiple degrees of freedom and multiple fingers, it is possible to ensure gripping stability. However, in a multi-degree-of-freedom multi-finger hand, it is impossible to avoid an increase in size and a complication of the structure, and in many of its examples, since a mechanism for interlocking the DIP joint and the PIP joint is adopted, it is difficult to ensure sufficient operability. The same applies to a underactuated hand driven by tendons, and it is difficult to sufficiently cope with the adjustment of the relative angles between the fingers.

[0088] On the other hand, according to the present embodiment, by changing the relative positions and angles of the finger ventral surfaces 21, 31a, and 31b of the first finger 2 and the second finger 3 according to the size and shape of the object, etc., the contact area of the robot hand H required for gripping the object can be ensured, and the gripping stability of the robot hand H can be ensured. Here, in the present embodiment, two fingers 2 and 3 are provided. One of the first fingers 2 has no degrees of freedom in the bending and extending directions, and the other second finger 3 has, in addition to the degree of freedom in the rotational direction at the joint (proximal joint j1) of the base portion, two joints (intermediate joint j2, distal joint j 3) By adopting a configuration having degrees of freedom in the bending and extending directions, the degrees of freedom given to the fingers can be minimized, and an increase in the number of parts can be suppressed. Thus, according to the present embodiment, it is possible to achieve both ensuring gripping stability and suppressing an increase in size accompanying an increase in degrees of freedom.

[0089] Since the first finger 2 has no degrees of freedom in the bending and extending directions, high-load manipulation of a heavy object becomes possible. For example, manipulations such as pushing, pulling, rotating, crushing, hitting, rubbing, supporting, and hooking and moving the object are possible. Furthermore, since there is no rattling of the joint due to backlash, highly accurate operation by the first finger 2 becomes possible. And by reducing the degrees of freedom, joints can be eliminated, making it easy to perform treatments such as waterproofing and dustproofing.

[0090] Since the finger width of the first finger 2, particularly the finger width of the fingertip portion of the first finger 2, is narrow, manipulation of a fine object becomes possible. For example, it becomes easy to perform operations such as inserting the fingertip portion into a narrow depression or recess (hooking on a handle and pulling the target part), or pressing the narrow surface with the fingertip (locally pressing the object). Furthermore, for an object having a shell shape, while applying the finger ventral surface 21 of the first finger 2 to the inner surface of the shell, applying the finger ventral surface 31a of the second finger, particularly its distal phalanx portion l3, to the outer surface of the shell, Edge pinching the object to ensure the contact area with both the inner surface and the outer surface of the shell, and providing stable gripping.

[0091] On the other hand, since the finger width of the second finger 3 is wide, a mounting space for an actuator that drives the joint of the second finger 3 is secured (in other words, a large actuator is mounted to increase the gripping force), and it becomes easy to mount a sensor on the second finger 3. For example, it is possible to mount a plurality of sensors on each of the link portions between the joints, that is, the proximal phalanx l1, the middle phalanx l2, and the distal phalanx l3.

[0092] By making the first finger 2 rotatable about the fourth axis Ax4 parallel to the central axis Ax0 of the palm part 1, the relative angles of the finger abdominal surfaces 21, 31a, 31b of the first finger 2 and the second finger 3 are changed within a plane perpendicular to the central axis Ax0 of the palm part 1, and it becomes possible to grip an object having an inclined surface or a tapered shape by matching the angle or orientation of the finger abdomen. Furthermore, during gripping, it is possible to adjust the positional relationship between the first finger 2 and the second finger 3 according to the dimensions of the object, thereby optimizing the gripping force. By rotating the first finger 2 about the fourth axis Ax4, bringing the first finger 2 and the second finger 3 closer to each other, and reducing the volume of the space occupied by the entire robot hand H, it is possible to reduce the storage space and cope with applications in narrow spaces.

[0093] By spreading the first finger 2 within a plane perpendicular to the central axis Ax0 of the palm part 1, it becomes possible to naturally perform an interaction involving contact, such as shaking hands with a person, and to cope with applications in a state where the palm part 1 is widely opened (for example, an operation such as wiping a table). And by arranging a pair of robot hands H in such an operation mode in a mirror-symmetric manner with respect to each other, it becomes possible to perform gripping with both hands using both arms, and to take an approach of supporting an object with a large plane or holding it sandwiched from both sides. In that case, it is possible to avoid the first finger 2 from getting in the way.

[0094] The wrist part 5 makes it possible to adjust the angle when the finger abdominal surface 21 of the first finger 2 contacts the object, and it becomes possible to realize higher gripping stability.

[0095] [Explanation of Modification Example 1.6] (1.6.1. First Modification Example) FIG. 22 is a perspective view showing a first modification example of the robot hand H according to the first embodiment of the present disclosure.

[0096] In the first modification example, a gripping assist unit U for assisting in gripping an object is installed on each joint portion l1, l2, l3 of the second finger 3. As an example of what can be applied to the gripping assist unit U, a variable adhesion unit or a variable friction unit whose adhesive force or frictional force can be adjusted can be exemplified. As the gripping assist unit U, it is also possible to employ a variable suction unit that applies a suction force to the object and can adjust this suction force.

[0097] (1.6.2. Second Modification Example) FIG. 23 is a perspective view showing a second modification example of the robot hand H according to the first embodiment of the present disclosure.

[0098] In the second modification example, a brake mechanism B configured to be able to fix the relative positional relationship of the base joint portion l1, the middle joint portion l2, and the distal joint portion l3 is installed on the robot hand H. As an applicable brake mechanism B, a wire-driven brake mechanism can be exemplified. The brake mechanism can assist the gripping force by the actuator and form a gripping force by the mechanical limit of the brake mechanism that does not depend on the output of the actuator.

[0099] Instead of or in addition to the brake mechanism, it is also possible to provide a biasing mechanism that can bias the proximal joint j1, the intermediate joint j2, and the distal joint j3 in the bending or extending direction of the second finger 3. By the biasing mechanism, when the robot hand H stops, by bending the second finger 3 so as to fold the finger, it is possible to reduce the volume of the space occupied by the entire robot hand H and reduce the storage space.

[0100] <2. Second Embodiment> FIG. 24 is a perspective view showing the appearance of the robot hand H' according to the second embodiment of the present disclosure.

[0101] In this embodiment, the relationship between the finger widths of the first finger 2 and the second finger 3 provided on the robot hand H' is the reverse of that in the previous first embodiment. Thus, the robot hand H' can also be configured to have a first finger 2 with a wide finger width (especially the finger width at the tip) and a second finger 3 with a finger width (especially the finger width at the distal phalanx) narrower than that of the first finger 2. The fact that the first finger 2 has no degrees of freedom in the bending and extending directions and the second finger 3 has three degrees of freedom due to the proximal, intermediate, and distal joints j1, j2, and j3 is the same as in the previous first embodiment.

[0102] <3. Summary> As described above, the embodiments in the present disclosure have been described in detail with reference to the drawings. According to the embodiments in the present disclosure, it is possible to achieve both ensuring gripping stability and suppressing enlargement.

[0103] The technology of the present disclosure is not limited to the above specific aspects, and various modifications are possible, and combinations of modification examples are also possible.

[0104] Furthermore, not all of the configurations and operations described in each embodiment are essential as the configurations and operations of the present disclosure. For example, among the components in each embodiment, components not described in the independent claims indicating the highest-level concept of the present disclosure should be understood as optional components.

[0105] The terms used throughout this specification and the appended claims should be interpreted as "non-limiting" terms. For example, the terms "including" or "comprised of" should be interpreted as not being limited to the aspects described as being included, and the term "having" should be interpreted as not being limited to the aspects described as having.

[0106] The terms used in this specification are for convenience of explanation only and are not intended to limit the configuration, operation, etc. For example, terms such as "right", "left", "upper", and "lower" merely indicate directions on the drawing to be referred to. Furthermore, terms such as "inner" and "outer" indicate the direction toward the center of the element of interest and the direction away from the center of the element of interest, respectively. The same applies to terms similar to or having the same meaning as these terms.

[0107] The technology of the present disclosure may have the following configuration. According to the technology of the present disclosure having the following configuration, it is possible to achieve both ensuring gripping stability and suppressing enlargement. The effects achieved by the technology of the present disclosure are not necessarily limited to this, and may be any of the effects described in this specification.

[0108] (1) A palm part, a first finger extending distally from the palm part and having a finger pad surface facing the central axis of the palm part, and a second finger extending distally from the palm part and having a finger pad surface facing the finger pad surface of the first finger with the central axis interposed therebetween. The palm part has a proximal joint that rotatably connects the second finger to the palm part about a first axis. The first finger has no freedom of movement in the flexing and extending directions. The fingertip surface has a shape that moves away from the central axis of the palm as it approaches the fingertip from its base, and has an initial opening angle which is the angle formed between the straight line connecting the base and the tip of the fingertip surface and a reference line parallel to the central axis of the palm. The second finger includes a proximal phalanx close to the palm part, a distal phalanx provided more distally than the proximal phalanx, and a middle phalanx provided between the proximal phalanx and the distal phalanx. The middle phalanx is connected to the proximal phalanx so as to be bendable and extendable about a second axis, and the distal phalanx is connected to the middle phalanx so as to be bendable and extendable about a third axis. A robotic hand. (2) The robotic hand according to (1) above, wherein the first finger has a narrower finger width than the second finger. (3) The robotic hand according to (2) above, wherein the first finger has a narrower finger width at the fingertip part than the finger width of the distal phalanx of the second finger. (4) The initial opening angle is in the range of 10 degrees to 60 degrees, the above ( 1 ) robotic hand. ( 5) The first, second, and third axes are parallel to each other, from the above (1) to ( 4 ) any one of the robot hands. ( 6 ) The first axis is three-dimensionally intersecting with respect to the central axis of the palm part, from the above (1) to ( 5 ) any one of the robot hands. ( 7 ) The proximal joint is larger in diameter than the intermediate joint and the distal joint, from the above (1) to ( 6 ) any one of the robot hands. ( 8 ) The palm part Grip is provided with a sensor so as to be perceivable with respect to an object, from the above (1) to ( 7 ) any one of the robot hands. ( 9 ) The second finger has at least one of the distal phalanx part, the middle phalanx part, and the proximal phalanx part Grip provided with a sensor so as to be perceivable with respect to an object, from the above (1) to ( 8 ) any one of the robot hands. ( 10 ) The second finger is provided with the sensor in the distal phalanx part and the middle phalanx part, and the sensor provided in the distal phalanx part has a higher resolution than the sensor provided in the middle phalanx part, from the above ( 9 ) the robot hand. ( 11 ) The second finger is provided with the sensor in the distal phalanx part and the middle phalanx part, and the sensor provided in the middle phalanx part has a higher load range than the sensor provided in the distal phalanx part, from the above ( 9 ) or ( 10 ) the robot hand. ( 12 ) The first finger is further configured to be rotatable about a fourth axis that coincides with the central axis or is parallel to the central axis with respect to the palm part, from the above (1) to ( 11 ) any one of the robot hands. ( 13 ) The first axis and the fourth axis are three-dimensionally intersecting with each other, from the above ( 12 ) the robot hand. ( 14Further comprising a wrist portion connected to the proximal side of the palm portion and configured to be able to apply rotation about a fifth axis parallel or perpendicular to the central axis with respect to the palm portion, the robot hand according to any one of (1) above to ( 13 ). ( 15 ) The robot hand according to any one of (1) above to ( Proximal phalanx ), further comprising a braking mechanism configured to be able to fix the relative positional relationship of the Middle phalanx , the Distal phalanx . 14 ). ( 16 ) The robot hand according to any one of (1) above to ( 15 ), further comprising a biasing mechanism configured to bias the proximal joint, the intermediate joint, and the distal joint in the bending or extending direction of the second finger. ( 17 ) Having a proximal end portion and a distal end portion, an operating arm extending axially from the proximal end portion toward the distal end portion, and a robot hand connected to the distal end portion of the operating arm, the robot hand including a palm portion, a first finger extending distally from the palm portion and having a finger pad surface facing the central axis of the palm portion, and a second finger extending distally from the palm portion and having a finger pad surface facing the finger pad surface of the first finger with the central axis interposed therebetween, the palm portion having a proximal joint that rotatably connects the second finger to the palm portion about a first axis, the first finger having no degrees of freedom in the bending and extending directions, the second finger including a proximal phalanx portion closer to the palm portion, a distal phalanx portion provided more distally than the proximal phalanx portion, and a middle phalanx portion provided between the proximal phalanx portion and the distal phalanx portion, and further including an intermediate joint that bends and extends the middle phalanx portion relative to the proximal phalanx portion about a second axis, and a distal joint that bends and extends the distal phalanx portion relative to the middle phalanx portion about a third axis, a manipulator.

[0109] This application claims priority based on Japanese Patent Application No. 2020-112135 filed with the Japan Patent Office on June 29, 2020, and incorporates the entire contents of this application by reference.

[0110] Those skilled in the art will be able to conceive of various modifications, combinations, sub - combinations, and changes according to design requirements and other factors, and it is understood that they are included within the scope of the appended claims and their equivalents.

Claims

1. A palm part, a first finger extending distally from the palm part and having a fingertip surface facing the central axis of the palm part, a second finger extending distally from the palm part and having a fingertip surface facing the fingertip surface of the first finger with the central axis therebetween, comprising: the palm part has a proximal joint that rotatably connects the second finger to the palm part about a first axis, the first finger has no freedom of flexion and extension, and has a shape such that the fingertip surface moves away from the central axis of the palm part as it approaches the fingertip from its base, and has an initial opening angle which is the angle formed between the straight line connecting the base and the tip of the fingertip surface and a reference line parallel to the central axis of the palm part, the second finger comprises a proximal phalanx close to the palm part, a distal phalanx provided more distally than the proximal phalanx, and a middle phalanx provided between the proximal phalanx and the distal phalanx, and comprises an intermediate joint that connects the middle phalanx to the proximal phalanx so as to be bendable and extendable about a second axis, and a distal joint that connects the distal phalanx to the middle phalanx so as to be bendable and extendable about a third axis, a robotic hand.

2. the first finger has a narrower finger width than the second finger, the robotic hand according to Claim 1.

3. the first finger has a narrower finger width at the fingertip than the finger width of the distal phalanx of the second finger, the robotic hand according to Claim 2.

4. the initial opening angle is in the range of 10 degrees to 60 degrees, the robotic hand according to Claim 1.

5. the first, second, and third axes are parallel to each other, the robotic hand according to Claim 1.

6. the first axis intersects the central axis of the palm part three-dimensionally, the robotic hand according to Claim 1.

7. the proximal joint has a larger diameter than the intermediate joint and the distal joint, the robotic hand according to Claim 1.

8. the palm part is provided with a sensor that can be sensed with respect to an object to be grasped, the robotic hand according to Claim 1.

9. the second finger is provided with a sensor that can be sensed with respect to an object to be grasped on at least one of the distal phalanx, the middle phalanx, and the proximal phalanx, the robotic hand according to Claim 1.

10. the second finger is provided with the sensor on the distal phalanx and the middle phalanx, the sensor provided on the distal phalanx has a higher resolution than the sensor provided on the middle phalanx, the robotic hand according to Claim 9.

11. The second finger is provided with the sensor at the distal phalanx and the middle phalanx, The sensor provided at the middle phalanx has a higher load range than the sensor provided at the distal phalanx, The robotic hand according to claim 9.

12. The first finger is further configured to be rotatable about a fourth axis that coincides with or is parallel to the central axis with respect to the palm portion, The robotic hand according to claim 1.

13. The first axis and the fourth axis are three-dimensionally intersecting with each other, The robotic hand according to claim 12.

14. It further includes a wrist portion that is connected to the proximal side of the palm portion and is configured to be able to impart rotation about a fifth axis that is parallel or perpendicular to the central axis with respect to the palm portion, The robotic hand according to claim 1.

15. It includes a brake mechanism configured to be able to fix the relative positional relationship of the proximal phalanx, the middle phalanx, and the distal phalanx, The robotic hand according to claim 1.

16. It includes a biasing mechanism configured to bias the proximal joint, the intermediate joint, and the distal joint in the bending or extending direction of the second finger, The robotic hand according to claim 1.

17. An operating arm having a proximal end portion and a distal end portion and extending axially from the proximal end portion toward the distal end portion, A robotic hand connected to the distal end portion of the operating arm, Comprising, The robotic hand is, A palm portion, A first finger extending distally from the palm portion and having a finger pad surface facing the central axis of the palm portion, A second finger extending distally from the palm portion and having a finger pad surface facing the finger pad surface of the first finger across the central axis, Comprising, The palm portion has a proximal joint that rotatably connects the second finger to the palm portion about a first axis, The first finger has no degree of freedom in the bending and extending directions, and the finger pad surface has a shape that moves away from the central axis of the palm portion as it approaches the fingertip portion from its base portion, and has an initial opening angle that is an angle formed between a straight line connecting the base portion and the tip portion of the finger pad surface and a reference line parallel to the central axis of the palm portion, The second finger is, A proximal phalanx close to the palm portion, a distal phalanx provided more distally than the proximal phalanx, and a middle phalanx provided between the proximal phalanx and the distal phalanx, and is provided with, The middle phalanx is connected to the proximal phalanx through an intermediate joint that is bendable and extendable about a second axis, and the distal phalanx is connected to the middle phalanx through a distal joint that is bendable and extendable about a third axis. Manipulator.

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