Robot hand device

Abstract

To provide a robot hand device capable of executing gripping operation of a finger joint suitable for an object by using a new control element such as sliding resistance.SOLUTION: A bending drive means 51 that bends the phalanges a to e of the joint mechanism 50, and a rotation range adjustment means 52 that is provided at a rotation portion of the phalanges a to e and adjusts a rotation range of each of the phalanges a to e by the bending drive means 51 are provided, and the rotation range adjustment means 52 includes a variable load mechanism 53 that individually adjusts a rotation sliding resistance of the rotation portion of the phalanges a to e by voltage application.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a humanoid robot hand device that can bend the phalanges that make up the five fingers in stages according to the shape and condition (hard, soft, brittle, etc.) of an object. [Background technology]

[0002] A typical five-fingered robotic hand is often attached to a multi-jointed robotic arm and operated in an integrated environment so that it can perform the same movements as a human. In such a robot hand, the phalanges must be bent appropriately depending on the shape and condition (hard, soft, brittle, etc.) of the object to be grasped.

[0003] As this type of robot, the technologies described in Patent Documents 1 and 2 are disclosed. The robot hand shown in Patent Document 1 has fingers whose outer shape is formed by a group of wires in which multiple loop-shaped elastic wires are arranged at predetermined intervals, a motor (for example, a servo motor, a stepping motor, or a combination of a motor and a gear) for driving the joints, and a displacement sensor installed around the tip of the group of wires to detect the load when it comes into contact with an object. The control unit of this robot hand then controls the motor to perform a bending motion of the phalanx in response to the load around the tip of the wire group detected by the displacement sensor.

[0004] The robot hand shown in Patent Document 2 is equipped with elastic parts provided in the finger body parts where a gripping force acts when the fingers grip an object, and tactile sensors provided at each joint that detect the reaction force when the joint is bent. In this robot hand, the joints of the fingers are bent in sequence by energizing the motors for each joint in the fingers in sequence, starting from the base of the finger. In this case, this robot hand bends the fingers in order, starting from the joints at the base, to grasp the object by enveloping it, thereby preventing strong localized stimuli from being applied to the object and enabling a soft and reliable grasping action. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-160022 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-001359 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, in the robot hands shown in Patent Documents 1 and 2, the phalanges / joints are bent by controlling the drive of a motor, but it is difficult to perform detailed control of the order in which the phalanges / joints move and the degree of bending, etc., and there is a problem in that it is not possible to perform a gripping operation appropriate for the object.

[0007] This invention has been made in consideration of the above-mentioned circumstances, and provides a robot hand device that is capable of performing a grasping operation of the phalanges appropriate for an object by using a new control element called sliding resistance. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention proposes the following means. A robot hand device according to a first aspect of the present invention has a plurality of rotatably connected phalanges, each of which constitutes a finger part, and is equipped with a joint mechanism in which the finger parts are rotatably connected to a hand main body, bending drive means for bending the phalanges of the joint mechanism, and rotation range adjustment means provided at rotation points of the phalanges for adjusting the rotation range of each of the phalanges caused by the bending drive means, wherein the rotation range adjustment means comprises a variable load mechanism that adjusts the rotational sliding resistance of the rotation points of the phalanges individually by applying a voltage.

[0009] A second aspect of the present invention provides a joint operation method for a robot hand device having a joint mechanism in which a plurality of rotatably connected phalanges constitute individual finger parts, and in which the finger parts are also rotatably connected to a hand main body, the method comprising: a bending drive step for bending the phalanges of the joint mechanism; and a rotation range adjustment step for adjusting the rotation range of each of the phalanges by the bending drive step, the rotation range adjustment step comprising a resistance variable step for individually adjusting the rotational sliding resistance of each rotation point of the phalanges by applying a voltage. [Effects of the Invention]

[0010] According to the present invention, by providing a dedicated variable load mechanism that individually adjusts the rotational sliding resistance of the rotation points of the phalanx, it becomes possible to perform fine grasping operations of the phalanx that are suitable for the shape and condition (hard, soft, brittle, etc.) of the object. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are diagrams showing the minimum configuration of a robot hand device according to the present invention, in which (A) is a schematic diagram of the overall configuration, and (B) is a diagram showing a variable load mechanism. [Figure 2] FIG. 2 is a schematic configuration diagram showing finger parts of the robot hand device according to the embodiment. [Figure 3] FIG. 2 is a diagram showing an internal configuration of a finger part. [Figure 4]4A and 4B are diagrams showing an example of the operation of the variable load mechanism indicated by the symbol IV in FIG. 3, where (A) shows a state in which no voltage is applied to the coil, and (B) shows a state in which a voltage is applied to the coil. [Figure 5] 1A to 1D are diagrams showing a first example of a continuous operation of the robot hand device according to the embodiment. [Figure 6] 10(A) to 10(C) are diagrams showing a second example of a continuous operation of the robot hand device according to the embodiment. [Figure 7] 10(A) to 10(D) are diagrams showing a third example of a continuous operation of the robot hand device according to the embodiment. [Figure 8] FIG. 10 is a diagram illustrating a first modified example of the embodiment. [Figure 9] FIG. 10 is a diagram illustrating a second modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] The minimum configuration of a robot hand device 100 according to the present invention will be described with reference to FIGS. As shown in FIG. 1(A), this robot hand device 100 mainly comprises a joint mechanism 50, a bending drive means 51, and a rotation range adjustment means 52. The joint mechanism 50 has a plurality of phalanges a to c and phalanges d and e rotatably connected via phalange rotation axes (m1, m2, and m3), and these phalanges a to c and phalanges d and e constitute a plurality of finger parts 1 to 5 (five in the drawing, but this can be changed as appropriate). In addition, in this joint mechanism 50, these five finger parts 1 to 5 are rotatably connected to the hand main body 6 via rotation support shafts (n1, n2, n3).

[0013] The bending drive means 51 is for bending the phalanges a to e of the joint mechanism 50 from a reference position, and is composed of, for example, a motor, wires, and the like.

[0014] The rotation range adjustment means 52 is provided at the rotation points of the joint mechanism 50 for the fingers a to e, and adjusts the rotation range of each of the fingers a to e by the bending drive means 51, and varies the rotation resistance at each rotation point of the fingers a to e by adjusting the voltage, etc. Specifically, the rotation range adjusting means 52 is made up of a variable load mechanism 53 that adjusts the rotational sliding resistance of the rotational parts of the phalanges a to e individually by applying a voltage as shown in FIG. 1(B).

[0015] The robot hand device 100 according to the present invention described above is configured such that, in addition to the bending drive means 51 that bends the phalanges a to e of the joint mechanism 50, a variable load mechanism 53 is provided at the rotation points of the phalanges a to e to individually adjust the rotational sliding resistance of the rotation points of the phalanges a to e by applying a voltage, thereby adjusting the rotation range of each of the phalanges a to e. That is, in the robot hand device 100 of the present invention, by providing a dedicated variable load mechanism 53 that individually adjusts the rotational sliding resistance of the rotation points of the fingers a to e, it becomes possible to perform fine grasping operations of the fingers a to e that are suitable for the shape and condition (hard, soft, brittle, etc.) of the object.

[0016] (Embodiment) A robot hand device 101 according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, the robot hand device 101 has as its main components a joint mechanism 20, a bending drive means 21, and a rotation range adjustment means 22, and is installed at the tip of a multi-jointed robot arm (not shown).

[0017] The joint mechanism 20 has a plurality of phalanges A to C rotatably connected via phalange rotation axes (M1, M2), and these plurality of phalanges A to C constitute, for example, five finger parts 11. In addition, in this joint mechanism 20, the finger part 11 is rotatably connected to the hand main body 16 via a rotation support shaft N1.

[0018] In the finger part 11, the phalangeal rotation axis M1 corresponds to the "first joint," the phalangeal rotation axis M2 corresponds to the "second joint," and the rotation support axis N1 corresponds to the "third joint." Specifically, in the joint mechanism 20 of the finger part 11, the phalanges rotation axes M1, M2 and the rotation support axis N1 of the three phalanges A to C are arranged in a positional relationship that is parallel or nearly parallel to one another, and are provided so as to be able to rotate freely from the reference position O in the initial state shown in FIG. 2 on the palm side in the plus (+) direction (arrow P1 direction) or on the back side in the minus (-) direction (arrow R1 direction).

[0019] The bending drive means 21 drives the phalanges A to C of the joint mechanism 20 to palmarly flex toward the flat side, which is in the positive direction (arrow P1 direction) from the reference position O, or to dorsiflex toward the back side, which is in the negative direction (arrow R1 direction) from the reference position O, and is composed of, for example, a wire 30. The wires 30 are provided for each finger part 11, and two wires are connected to the phalanges A located at the tip of each finger part 11. In addition, the wire 30 of each finger part 11 is positioned slightly offset toward the palm side / back side from the rotation center of the phalangeal rotation axis (M1, M2) and the rotation support axis (N1) in order to apply a bending force to each finger part 11. The wires 30 of the finger parts 11 are pulled or pulled by actuators 41 installed at any part of the structure that constitutes the hand, wrist, or arm.

[0020] The rotation range adjusting means 22 is provided at the rotation points of the phalanges A to C and adjusts the rotation range of each of the phalanges A to C by the bending drive means 21, and varies the rotation resistance at each rotation point of the phalanges A to C by adjusting the voltage, etc. Specifically, the rotation range adjusting means 22 is made up of a variable load mechanism 24 that adjusts the rotational sliding resistance of the rotational parts of the phalanges A to C individually by applying a voltage.

[0021] Furthermore, in this variable load mechanism 24, the rotation resistance at each rotation point of the phalanges A to C is made variable by adjusting the voltage or the like, thereby changing the sliding load and controlling the order in which each joint moves. The variable load mechanism 24 of the rotation range adjustment means 22 is provided on the phalangeal rotation axis M1, which is the "first joint," the phalangeal rotation axis M2, which is the "second joint," and the rotation support axis N1, which is the "third joint," of the finger part 11.

[0022] A specific configuration of the variable load mechanism 24 will be described with reference to FIGS. 3 and 4 show an example of a variable load mechanism 24 located between the phalanges A and B of the finger part 11. 4(A), the variable load mechanism 24 is an electromagnetic brake having a shaft 25 serving as a phalanx rotation axis M1 that rotatably connects phalanx A and phalanx B, a coil 26 fixed to the shaft 25 via a coil holder 26A, a rod 27 made of a magnetic material that is affected by a magnetic field generated by energizing the coil 26, and an outer ring 28 to which the rod 27 is fixed. Note that energization of the coil 26 is controlled by turning a switch 29 on and off.

[0023] In these configurations, the shaft 25 and the coil 26 are fixed to the phalanx A side, and the rod 27 and the outer ring 28 are installed so as to be movable in the axial direction relative to the shaft 25. In addition, a bearing (not shown) is installed between the shaft 25 and the phalanx B. In such a variable load mechanism 24, when electricity is applied to the coil 26 as shown in FIG. 4(B), the rod 27 moves left and right along the shaft 25, and the outer ring 28 integral with the rod 27 comes into contact with and slides against the phalanx B (the contact and sliding point is indicated by the symbol 28A in FIG. 4(B)). This allows the variable load mechanism 24 to apply a sliding load to the relative rotation of the phalanges A and B.

[0024] As a result, the rotation range adjustment means 22 selectively energizes the coils 26 of the variable load mechanisms 24 provided on the phalange rotation axes M1, M2 and the phalange support axis N1 of the phalanges A to C, respectively, thereby enabling free operation to rotate / stop the rotation of the rotational portions of the phalanges A to C. At this time, by adjusting the magnitude of the current / voltage supplied to each coil 26 in the variable load mechanism 24, it is possible to freely adjust not only whether or not the phalanges A to C rotate, but also the amount of rotation, i.e., the rotation angle.

[0025] In addition, a contact sensor 31 is provided on the surface of the finger part 11 as shown in FIGS. The contact sensors 31 detect whether an object is being grasped or not, and are installed on both the palm side and the back side of the finger parts 11 (only one side is shown in the figure). These contact sensors 31 are arranged on an elastic sheet 42 (see FIG. 2) that covers the finger parts 11.

[0026] Next, the operation of the variable load mechanism 24 of the rotation range adjusting means 22 will be described with reference to FIGS. As shown in Figures 4(A) and 4(B), when a voltage is applied to the variable load mechanism 24 of the phalanges A to C on which a sliding load is to be generated, the magnetic force generated in the coil 26 draws the rod 27, which is a magnetic body, into the coil 26, causing the outer ring 28 to come into contact with the phalanges A to C (phalange B in this example), generating a rotational load between the shaft 25, which serves as the rotation axis, and the phalanges A to C.

[0027] Thereafter, when the wire 30 is pulled, the phalanges A to C begin to bend. At this time, the phalanges A to C with a lighter load start to move faster and rotate more widely, while the phalanges A to C with a heavier load begin to rotate only after the phalanges A to C with a lighter load have completely bent. That is, the rotation range adjustment means 22 maximizes the load of the variable load mechanism 24 and locks the targeted phalanges A to C, thereby realizing control to bend the phalanges A to C individually without causing them to move in the same way.

[0028] 5(A) to 5(D) show examples of movements for grasping a relatively small object with the phalanges A to C of the finger part 11. First, in the variable load mechanism 24 of the rotation range adjustment means 22, the sliding load is set so that "first phalanx A (phalanx rotation axis M1) < second phalanx B (phalanx rotation axis M2) < third phalanx C (phalanx support axis N1)", and then the wire 30 on the specified side is pulled by the actuator 41 of the bending drive means 21 (see Figure 2).

[0029] As a result, the first phalanx A bends first and finishes bending, then the second phalanx B starts to bend slowly, followed by the third phalanx C. At this time, when the bending state of phalanxes A and B reaches an angle where the object can be pinched between phalanxes A and B, the sliding load on the third phalanx C is reduced to control the degree of bending. As a result, the robot hand device 101 can pinch a relatively small object by bending the five finger parts 11.

[0030] 6(A) to 6(C) show examples of movements for grasping a thin object such as paper or a card with the phalanges A to C of the finger part 11. First, in the variable load mechanism 24 of the rotation range adjustment means 22, the sliding load is set so that "first phalanx A (phalanx rotation axis M1) = second phalanx B (phalanx rotation axis M2) > third phalanx C (phalanx support axis N1)", and then the wire 30 on the specified side is pulled by the actuator 41 of the bending drive means 21 (see Figure 2). As a result, the third phalanx C bends first and then finishes bending, after which the first phalanx A and the second phalanx B slowly begin to bend. This allows the robot hand device 101 to pinch thin objects such as paper or cards by bending the five finger parts 11.

[0031] FIG. 7 shows an example of the movements of the phalanges A to C of the finger part 11 using the detection signals of the contact sensor 31. In the variable load mechanism 24 of the rotation range adjustment means 22, when the contact sensor 31 detects that the object to be grasped S1 has been pinched or pinched, the operation of the actuator 41 is gradually stopped, thereby enabling the object to be grasped without being crushed.

[0032] For example, in the variable load mechanism 24 of the rotation range adjusting means 22, when grasping a fragile object S1 such as an egg, first the sliding resistance of only the third phalanx C (phalanx support axis N1) is reduced to allow it to move. Thereafter, when the variable load mechanism 24 detects that the contact sensor 31 of the third phalanx C has come into contact with the object S1, it maximizes the sliding resistance of the third phalanx C to stop its movement, as shown in Figures 7(A) to (B), and reduces the sliding resistance of the second phalanx B (phalanx rotation axis M2) to allow the second phalanx B to move. Thereafter, when the variable load mechanism 24 detects that the contact sensor 31 of the second phalanx B has come into contact with the object S1, it maximizes the sliding resistance of the second phalanx B to stop its movement, as shown in Figures 7(B) to (C), and reduces the sliding resistance of the first phalanx A (phalanx rotation axis M1) to allow the first phalanx A to move.

[0033] Thereafter, when the contact sensor 31 of the first phalanx A detects that it has come into contact with the object S1, the variable load mechanism 24 stops pulling the wire 30 as shown in FIGS. 7(C) and 7(D). Furthermore, by providing the contact sensors 31 on both the palm side and the back side of the robot hand device 101, it becomes possible to freely grip a fragile object S1 by bending the phalanges A to C of the finger parts 11 to either the palm side or the back side.

[0034] According to the robot hand device 101 of this embodiment described above, in addition to the bending drive means 21 that bends the fingers A to C of the joint mechanism 20, a variable load mechanism 24 is provided at the rotation points of the fingers A to C to individually adjust the rotational sliding resistance of the rotation points of the fingers A to C by applying a voltage, thereby adjusting the rotation range of each of the fingers A to C. That is, in the robot hand device 101 of this embodiment, by providing a dedicated variable load mechanism 24 that individually adjusts the rotational sliding resistance of the rotation points of the fingers A to C, it becomes possible to perform fine grasping operations of the fingers A to C that are suitable for the shape and condition (hard, soft, brittle, etc.) of the object.

[0035] (Variation 1) In the variable load mechanism 24 of the above embodiment, the outer ring 28 is slid over the phalanges A to C (phalange B in the example of FIG. 4) to restrict the relative rotation of the phalanges A to C. However, this is not limited to this. As shown in FIG. 8, the coil 26, rod 27, and outer ring 28 may not be used, and instead, a shape memory shaft 32 made of a shape memory alloy may be used to restrict the relative rotation of the phalanges A to C.

[0036] This shape memory shaft 32 is provided in place of the shaft 25 shown in Figure 4, and by applying a voltage to both sides of it to change its shape, it generates rotational sliding resistance in the adjacent phalanges A to C. In addition, FIG. 8 shows an example in which a shape memory shaft 32 is used for the shafts of the phalangeal rotation axes M1 and M2, and the phalangeal rotation axis M1 to which no voltage is applied and no deformation occurs is shown by a "solid line," and the phalangeal rotation axis M2 to which voltage is applied and deformation occurs is shown by a "dashed line."

[0037] (Variation 2) Furthermore, in the variable load mechanism 24 of the above embodiment, the outer ring 28 is caused to slide over the phalanges A to C (phalange B in the example of FIG. 4) to restrict the relative rotation of the phalanges A to C. However, this is not limited to this. As shown in FIG. 9, instead of the coil 26, rod 27, and outer ring 28, a shape memory spring 33 made of a shape memory alloy may be used to restrict the relative rotation of the phalanges A to C.

[0038] This shape memory spring 33 changes its shape when a voltage is applied to both sides thereof, tightening the shaft 25 and generating rotational sliding resistance in the adjacent phalanges A to C.

[0039] The present invention can be generally applied to any object that performs bending and stretching movements. Furthermore, although this invention focuses on the "hand," when considering bending and stretching movements, this can be replaced with the elbow, knee, foot, etc., and can also be applied to machines that model the structure of the human body. Furthermore, prosthetic limbs and artificial limbs are medical devices that replicate the movements of various parts of the human body and act as second limbs. The technology of the present invention can also be applied to this field.

[0040] Although the embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0041] The present invention relates to a humanoid robot hand device and a robot hand operation method that can bend the phalanges that make up the five fingers in stages according to the shape and condition (hard, soft, brittle, etc.) of an object. [Explanation of symbols]

[0042] 1 finger part 2 finger parts 3 Finger parts 4 Finger parts 5 Finger parts 6 Hand body 11 Finger parts 16 Hand body 20 Joint Mechanism 21 Bending drive means 22 Rotation range adjustment means 24 Variable load mechanism 25 shaft 26 coils 27 Rod 28 outer ring 29 Switch 30 wire 31 Contact Sensor 32 Shape memory shaft 33 Shape memory spring 41 Actuator 42 Elastic Sheet 50 Joint Mechanism 51 Bending drive means 52 Rotation range adjustment means 53 Variable load mechanism a phalanx b phalanx c phalanx d phalanx e phalanx A phalanx B phalanx C phalanx m1 Phalangeal rotation axis m2 phalangeal rotation axis m3 Phalangeal rotation axis n1 Rotation support shaft n2 Rotation support shaft n3 Rotation support shaft M1 phalangeal rotation axis M2 Phalangeal rotation axis N1 Rotation support shaft P1 Flat side R1 Back side S1 Object 100 Robot hand device 101 Robot hand device

Claims

1. a joint mechanism having a plurality of phalanges rotatably connected to each other, each of which constitutes a finger part, and the finger parts are rotatably connected to the hand main body; a bending drive means for bending the phalanges of the joint mechanism; a rotation range adjusting means provided at a rotation point of the phalanges and configured to adjust the rotation range of each of the phalanges caused by the bending drive means; the rotation range adjusting means comprises a variable load mechanism that adjusts the rotational sliding resistance of each of the rotational points of the phalanx individually by applying a voltage; The variable load mechanism is a robot hand device characterized in that the rotation axis / support axis of the joint mechanism is constructed using a shape memory shaft, and rotational sliding resistance is generated by deforming the shape memory shaft when a voltage is applied.

2. a joint mechanism having a plurality of phalanges rotatably connected to each other, each of which constitutes a finger part, and the finger parts are rotatably connected to the hand main body; a bending drive means for bending the phalanges of the joint mechanism; a rotation range adjusting means provided at a rotation point of the phalanges and configured to adjust the rotation range of each of the phalanges caused by the bending drive means; the rotation range adjusting means comprises a variable load mechanism that adjusts the rotational sliding resistance of each of the rotational points of the phalanx individually by applying a voltage; The variable load mechanism has a shape memory spring that constrains the rotation point of the joint mechanism, and generates rotational sliding resistance by deforming the shape memory spring when a voltage is applied.

3. 3. The robot hand device according to claim 1, wherein the rotation range adjusting means adjusts the rotational sliding resistance of the variable load mechanism in sequence to bend the phalanx in stages.

4. The robot hand device according to any one of claims 1 to 3, characterized in that the bending drive means causes the phalanges of the joint mechanism to bend palmarly toward the flat side, which is a positive direction from a reference position, and dorsiflex toward the back side, which is a negative direction from the reference position.

5. 5. The robot hand device according to claim 1, wherein the bending drive means comprises a wire that pulls / relaxes the phalanges of the joint mechanism.

6. 6. The robot hand device according to claim 5, wherein the wire is connected to a first phalanx of the finger part.

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