Grippers and robots

Abstract

To realizes various gripping postures in a gripper, thereby expanding a grippable range.SOLUTION: A gripper is provided which has a plurality of claws 54R and 54, and each claw is opened and closed by a drive link provided between each claw and a body section 51, respectively. In the gripper, a claw joint section 53R for rotating each claw around a shaft parallel to an opening / closing operation direction with respect to each driving link is provided between each claw and each driving link.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a gripper or a robot equipped with a gripper. [Background technology]

[0002] In recent years, attempts have been made to introduce robots into logistics sites, etc. In such sites, robots are required to perform tasks such as grasping an object, moving it, and then placing it again (e.g., palletizing work).

[0003] Various end effectors or hands can be used to realize gripping by a robot. For example, there is a gripper that performs gripping by opening and closing multiple claws (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-001281 Summary of the Invention [Problem to be solved by the invention]

[0005] When gripping an object using a gripper, it is common to reach out with the jaws held horizontally to the object. Therefore, when reaching out to an object using a conventional gripper such as that shown in Patent Document 1, it was necessary to make the entire gripper, including the jaws, parallel to the object.

[0006] However, if the gripping posture of the gripper is limited in this way, there is a risk that the range in which the object can be gripped may be limited.

[0007] The present invention has been made in view of the above-mentioned technical background, and has an object to realize a variety of gripping postures in a gripper, thereby expanding the possible gripping range. [Means for solving the problem]

[0008] The above-mentioned technical problems can be solved by a gripper or robot having the following configuration.

[0009] In other words, the gripper of the present invention is a gripper having a plurality of claws, which are opened and closed by drive links respectively provided between each of the claws and a main body, and between each of the claws and each of the drive links, a claw joint portion is provided which rotates each of the claws around an axis parallel to the opening and closing direction relative to each of the drive links.

[0010] With this configuration, in addition to the opening and closing movement of the claws, the claws can be rotated relative to the drive link. This allows the gripper to achieve a variety of gripping positions, thereby expanding the possible gripping range. The drive link is a driven link interposed between the main body and the claws, and includes components such as an output link and a claw connector.

[0011] In each of the claw joint portions, the claws may be driven independently of each other.

[0012] With this configuration, it is possible to have only some of the claws act on the object to be grasped, and various actions can be realized, such as pushing an object placed on the side.

[0013] The drive links may be driven independently of each other.

[0014] With this configuration, the gripping center position of the gripper can be freely changed depending on the position of the object to be gripped.

[0015] The number of the claws may be two, and the claws may open and close in a state parallel to each other.

[0016] With this configuration, gripping can be performed by opening and closing a pair of parallel claws. This allows for gripping with a minimal configuration. In addition, the number of parts can be reduced, leading to cost savings.

[0017] Each of the drive links may be driven by a linear motion mechanism.

[0018] With this configuration, the opening and closing operation of the claw can be achieved with a simple configuration.

[0019] Each of the linear motion mechanisms may include either a ball screw or a slide screw, and a linear guide.

[0020] With this configuration, the drive link can be driven by a highly reliable linear motion mechanism.

[0021] A detection means for detecting a force or moment acting on each of the claws may be further provided between each of the claws and each of the drive links.

[0022] With this configuration, the force or moment acting on each jaw near the gripping position can be directly detected.

[0023] The device may further include an external force calculation unit that calculates the external force acting in the opening and closing directions of each claw.

[0024] According to this configuration, it is possible to detect external forces acting in the opening and closing directions of each claw, thereby improving the accuracy of gripping control by the claws.

[0025] The gripping device may further include a closing drive unit that drives any of the claws to perform a closing operation, a contact detection unit that detects whether the claws performing the closing operation have come into contact with the object to be grasped, an operation stop unit that stops the operation of the claws when it is detected that the claws have come into contact with the object to be grasped, a repetitive execution processing unit that repeatedly executes a series of processes by the closing drive unit, the contact detection unit, and the operation stop unit until all of the claws have stopped, and a gripping control unit that controls each of the claws to apply a target gripping force to the object to be grasped when all of the claws have stopped operating.

[0026] With this configuration, the advantage of being able to independently drive the claws can be utilized to perform gripping control according to the position of the object to be gripped.

[0027] Each of the claws may extend so that its end face on the floor side is closer to the floor side than to the surface of the housing of the main body.

[0028] With this configuration, the floor-side end face of each claw extends closer to the floor than the surface of the housing of the main body, so even when the gripper is used near the floor, the housing of the main body does not come into direct contact with the floor, thereby protecting the housing of the main body.

[0029] Each of the claws may be provided with a gripping member that rotates relative to the claw about an axis parallel to the direction of the opening and closing movement.

[0030] With this configuration, gripping can be performed with a higher degree of freedom.

[0031] Each of the claws may be provided with a gripping member which pivots relative to the claw about an axis perpendicular to the longitudinal axis of the claw. With this configuration, gripping can be performed with a higher degree of freedom.

[0032] A chuck hand may be attached to each of the jaws.

[0033] With this configuration, gripping can be performed with a higher degree of freedom.

[0034] From another aspect, the present invention is a robot. That is, the robot according to the present invention includes a gripper having a plurality of claws, each of which is opened and closed by a drive link provided between each of the claws and a main body, and each of which is provided with a claw joint between each of the claws and each of the drive links for rotating each of the claws relative to each of the drive links about an axis parallel to the opening and closing direction of the gripper, a movement mechanism, and a plurality of drive joints arranged between the gripper and the movement mechanism.

[0035] With this configuration, the gripper can achieve a variety of gripping positions, thereby expanding the possible gripping range. Furthermore, as the gripper moves, the gripper position can be freely controlled by the multiple drive joints. Therefore, various objects can be gripped flexibly and precisely. The drive link is a driven link interposed between the main body and the claws, and includes components such as an output link and a claw connector.

[0036] The movement mechanism may be an omnidirectional moving carriage.

[0037] With this configuration, the gripper can be moved freely.

[0038] The omnidirectional moving carriage may be driven by omni-wheels.

[0039] According to this configuration, the gripper can be freely moved using the omni-wheel.

[0040] The drive joint may include a first joint that rotates the gripper about a first axis that extends in a vertical direction.

[0041] According to this configuration, the gripper itself can be rotated around the vertical axis by the first joint portion, so that gripping by the gripper can be performed more easily.

[0042] The claws and the first joints may be controlled in a coordinated manner by solving inverse kinematics.

[0043] With this configuration, the movements of the claw and the joint are linked, so that gripping can be performed with the gripper position optimized.

[0044] In each of the claw joint portions, the claws may be driven independently of each other.

[0045] With this configuration, it is possible to have only some of the claws act on the object to be grasped, and various actions can be realized, such as pushing an object placed on the side.

[0046] The drive links may be driven independently of each other.

[0047] With this configuration, the gripping center position of the gripper can be freely changed depending on the position of the object to be gripped.

[0048] The number of the claws may be two, and the claws may open and close in a state parallel to each other.

[0049] With this configuration, gripping can be performed by opening and closing a pair of parallel claws. This allows for gripping with a minimal configuration. In addition, the number of parts can be reduced, leading to cost savings.

[0050] Each of the drive links may be driven by a linear motion mechanism.

[0051] With this configuration, the opening and closing operation of the claw can be achieved with a simple configuration.

[0052] Each of the linear motion mechanisms may include either a ball screw or a slide screw, and a linear guide.

[0053] With this configuration, the drive link can be driven by a highly reliable linear motion mechanism.

[0054] A detection means for detecting a force or moment acting on each of the claws may be further provided between each of the claws and each of the drive links.

[0055] With this configuration, the force or moment acting on each jaw near the gripping position can be directly detected.

[0056] The device may further include an external force calculation unit that calculates the external force acting in the opening and closing directions of each claw.

[0057] According to this configuration, it is possible to detect external forces acting in the opening and closing directions of each claw, thereby improving the accuracy of gripping control by the claws.

[0058] The external force calculation unit may calculate the external force on the claw from a force or moment applied to each of the drive joints.

[0059] With this configuration, the force or moment acting on the claw can be calculated without attaching a sensor or the like to the claw itself, so the gripper configuration can be simplified.

[0060] The gripping device may further include a closing drive unit that drives any of the claws to perform a closing operation, a contact detection unit that detects whether the claws performing the closing operation have come into contact with the object to be grasped, an operation stop unit that stops the operation of the claws when it is detected that the claws have come into contact with the object to be grasped, a repetitive execution processing unit that repeatedly executes a series of processes by the closing drive unit, the contact detection unit, and the operation stop unit until all of the claws have stopped, and a gripping control unit that controls each of the claws to apply a target gripping force to the object to be grasped when all of the claws have stopped operating.

[0061] With this configuration, the advantage of being able to independently drive the claws can be utilized to perform gripping control according to the position of the object to be gripped.

[0062] Each of the claws may extend so that its end face on the floor side is closer to the floor side than to the surface of the housing of the main body.

[0063] With this configuration, the floor-side end face of each claw extends closer to the floor than the surface of the housing of the main body, so even when the gripper is used near the floor, the housing of the main body does not come into direct contact with the floor, thereby protecting the housing of the main body.

[0064] From another aspect, the present invention is a robot. That is, the robot according to the present invention includes a gripper having two claws, drive links provided between each of the claws and a main body unit by linear motion mechanisms, respectively, to open and close the claws in a state parallel to each other, and claw joint units are provided between each of the claws and each of the drive links to rotate each of the claws relative to each of the drive links about axes parallel to the opening and closing movement direction, and the claws are driven independently of each other at each of the claw joint units, and the drive links are driven independently of each other, and the gripper includes a movement mechanism unit that moves on a floor surface, and a first joint unit that moves the moving mechanism unit. The gripper has a first link connected to a mechanism and rotatable about a first axis extending vertically relative to the moving mechanism, a second link connected to the first link via a second joint and rotatable about a second axis perpendicular to the first axis relative to the first link, and a third link connected to the second link via a third joint and sliding on an axis parallel to the second link relative to the second link, and the gripper is connected to the third link via a fourth joint and rotatable about a fourth axis parallel to the second axis relative to the third link.

[0065] With this configuration, in addition to the opening and closing movement of the claws, it is possible to realize rotation of the claws relative to the drive link. This allows the gripper to realize a variety of gripping postures, thereby expanding the possible gripping range. Furthermore, by independently driving the claws, it is possible to realize a variety of movements and freely change the gripping center position of the gripper. Furthermore, it is possible to simplify the structure. Furthermore, as the gripper moves, the gripper position can be freely controlled by multiple drive joints. Therefore, it is possible to flexibly and accurately grip various objects. The drive link is a driven link interposed between the main body and the claws, and includes components such as an output link and a claw connecting portion. [Effects of the Invention]

[0066] According to the present invention, a variety of gripping positions can be realized in the gripper, thereby expanding the possible gripping range. [Brief explanation of the drawings]

[0067] [Figure 1] FIG. 1 is a perspective view of the robot. [Figure 2] FIG. 2 is a perspective view of a gripper provided in the robot. [Figure 3] FIG. 3 is a functional block diagram of the robot. [Figure 4] FIG. 4 is an explanatory diagram regarding the independent driving of the output links. [Figure 5] FIG. 5 is an explanatory diagram regarding the change of the gripping position. [Figure 6] FIG. 6 is an explanatory diagram regarding the independent driving of the claw bending joints. [Figure 7] FIG. 7 is an explanatory diagram (part 1) regarding the advantages of providing a claw bending joint portion. [Figure 8] FIG. 8 is an explanatory diagram (part 2) regarding the advantages of providing a claw bending joint portion. [Figure 9] FIG. 9 is an explanatory diagram (part 3) regarding the advantages of providing a claw bending joint portion. [Figure 10] FIG. 10 is an explanatory diagram (part 1) regarding the protection of the housing using a claw shape. [Figure 11] FIG. 11 is an explanatory diagram (part 2) regarding the protection of the housing using a claw shape. [Figure 12] FIG. 12 is an explanatory diagram showing a process of gripping an object using a gripper. [Figure 13] FIG. 13 is an explanatory diagram showing the initial state of gripping. [Figure 14] FIG. 14 is an explanatory diagram showing the grasping preparation state. [Figure 15] FIG. 15 is a perspective view of a robot according to a first modified example. [Figure 16] FIG. 16 is a perspective view of a robot according to a second modified example. [Figure 17] FIG. 17 is a perspective view of a robot according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0068] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0069] (1. First embodiment) As a first embodiment, an example will be described in which the present invention is applied to a robot 100 equipped with a gripper 150. In this embodiment, a device that grips an object by reducing the distance between multiple members is called a gripper, but it may also be called by other names such as an end effector or a hand.

[0070] (1.1 Robot and Gripper Configuration) The configurations of the robot 100 and the gripper 150 will be described with reference to Figures 1 and 2. Figure 1 is a perspective view of the robot 100, and Figure 2 is a perspective view of the gripper 150 provided in the robot 100.

[0071] As is clear from Figure 1, the robot 100 of this embodiment is composed of a cart unit 11, which is a moving mechanism for moving on the floor surface, a multi-joint arm unit (21, 31, 41, 42) with the top surface of the cart unit 11 as its base end, and a gripper 150 attached to the tip of the multi-joint arm unit.

[0072] 1 may be referred to as "up," the vertically upward direction as "up," the vertically downward direction as "down," the surface on which the gripper 150 is provided as the front, and the opposite side as the back. Furthermore, with the back as your back, the right side may be referred to as "right," the left side as "left," and both the left and right sides may be referred to as "sides."

[0073] The cart unit 11 has a roughly cylindrical housing that tapers slightly upward, with a flat surface on the top surface of the housing. Four omni-wheels 12 are provided on the bottom side of the interior of the housing of the cart unit 11. The omni-wheels 12 are wheels that enable movement in all directions by combining the rotation of the wheels and the rotation of a barrel on the circumference. These omni-wheels 12 allow the cart unit 11 to move freely in all directions.

[0074] Although this embodiment employs an omni-wheel as the omnidirectional movement mechanism, the present invention is not limited to this configuration. Therefore, other wheels that enable omnidirectional movement, such as Mecanum wheels, may be employed. The movement mechanism is not limited to an omnidirectional movement mechanism. Therefore, other movement mechanisms with limited movement directions may be employed. Furthermore, the movement mechanism may be any mechanism that can move the articulated arm unit and the gripper 150. Therefore, for example, the movement mechanism is not limited to one that moves on the floor surface, and may be a movement mechanism suspended from the ceiling, a flying movement mechanism, or the like.

[0075] A first link 21 is connected to the top surface of the carriage unit 11 via a first joint unit (J1). The first joint unit (J1) rotates the first link 21 relative to the carriage unit 11 around a first axis extending in the vertical direction. The first joint unit (J1) is a drive joint that is driven by an actuator (not shown).

[0076] An upper portion of the first link 21 is connected to a second link 31 via a second joint portion (J2). The second joint portion (J2) rotates the second link 31 relative to the first link 21 around a second axis, which is a horizontal axis perpendicular to the first axis. The second joint portion (J2) is a drive joint driven by an actuator (not shown).

[0077] The second link 31 has a J-shape, and a linear guide is provided on its straight portion. The third link 41 slides on this linear guide (third axis) to form a third joint (J3). In the posture shown in the figure, the third axis is a vertical axis.

[0078] The third link 41 has a hollow, substantially rectangular parallelepiped shape with an opening on the bottom surface. The third joint portion (J3) is a drive joint that is driven by an actuator (not shown).

[0079] A fourth link 42 is fixed to the upper front side of the third link 41. The gripper 150 is connected to the front end of the fourth link 42 via a fourth joint (J4). The fourth joint (J4) rotates the gripper 150 relative to the fourth link 42 around a fourth axis, which is a horizontal axis parallel to the second axis. The fourth joint (J4) is a drive joint that is driven by an actuator (not shown).

[0080] 1 and 2 (particularly FIG. 2), the gripper 150 is made up of a gripper main body 51 rotatably connected at its base end to the fourth link 42 via a fourth joint (J4), output links 52L, 52R extending laterally from the gripper main body 51 and moving linearly, claw connecting portions 53L, 53R attached to the tip ends of the output links 52L, 52R, and claws 54L, 54R connected to the insides of the claw connecting portions 53L, 53R. Note that the symbol L represents the left side configuration of the gripper 150, and R represents the right side configuration.

[0081] The gripper main body 51 is rotatably connected to the fourth link 42 via the fourth joint (J4), and its housing holds therein a linear motion mechanism that drives the output links 52L and 52R, its actuator, etc.

[0082] In this embodiment, the linear motion mechanism is composed of a ball screw and a linear guide. The output links 52L and 52R, which are linearly moved by the linear motion mechanism, protrude parallel to each other from openings provided above and below on the left and right side surfaces of the front side of the gripper body 51.

[0083] The output link 52R extending from the right side is driven to move linearly and constitutes a fifth joint (J5). Similarly, the output link 52L extending from the left side is driven to move linearly and constitutes a sixth joint (J6). By driving these output links 52L, 52R, opening and closing operations are realized while maintaining the claws 54L, 54R parallel to each other.

[0084] The linear motion mechanism is not limited to the one described above, and other mechanisms may be used. For example, other components such as a slide screw may be used instead of the ball screw.

[0085] Claw connecting parts 53L, 53R are attached to the tips of the output links 52L, 52R, and extend toward the front, perpendicular to the output links 52L, 52R. Inside the claw connecting parts 53L, 53R, actuators (not shown) are arranged to rotate the claws 54L, 54R attached to the inner surface thereof.

[0086] The claws 54L and 54R have a generally oval shape, but as will be described later, the claws 54L and 54R have a gently curved shape near the connection portions with the claw connection portions 53L and 53R.

[0087] The base end of the left claw 54L is rotatably connected to the inner surface of the claw connecting portion 53L and driven to form a seventh joint portion (J7). Similarly, the base end of the right claw 54R is rotatably connected to the inner surface of the claw connecting portion 53R and driven to form an eighth joint portion (J8). Hereinafter, for convenience, the seventh joint portion and the eighth joint portion may be referred to as claw bending joint portions (J7, J8), respectively.

[0088] The rotational movement of the claws 54L, 54R may be expressed as swinging. The term "claw" refers to a part of the gripper 150 that pinches and grips an object. Therefore, it may be expressed by other terms such as a pinching body, a pinching piece, a gripping body, or a gripping piece. There are no limitations on the size or shape, and the claws are not limited to small pieces.

[0089] In this embodiment, the first to eighth joints (J1 to J8) and the wheels of the carriage unit 11 are each equipped with various detection means. More specifically, the joints (J1, J2, J4, J7, J8) and the wheels of the carriage unit 11 are each equipped with an angle sensor (not shown), and the linearly moving joints (J3, J5, J6) are each equipped with a position sensor. Furthermore, the first to fourth joints (J1 to J4) are each equipped with a force sensor. Based on the detection values ​​from these sensors, the control unit 115 (described later) can calculate or estimate the posture of the robot 100 and the forces and moments applied to various parts of the robot 100.

[0090] For example, based on various detection values, it is possible to calculate the forces acting in three axial directions (x, y, z) at the tips of the claws 54L and 54R (see the arrows at the tips of the claws 54L and 54R in Figure 2). The z direction represents the direction of opening / closing movement, the direction of grasping movement, or the pushing direction, and the x and y directions represent the direction of contact with the environment.

[0091] In this embodiment, a configuration in which a force sensor is provided at each of the first to fourth joints (J1 to J4) has been described, but the present invention is not limited to such a configuration. Therefore, a sensor that serves as a means for detecting force or moment may be provided at the base of each of the claws 54L, 54R.

[0092] 3 is a functional block diagram of the robot 100. As is clear from the diagram, the robot 100 includes a microcomputer 110 therein, which is connected to actuators and sensors provided at each joint (J1 to J8) and the movable carriage.

[0093] In the figure, the first to eighth joints (J1 to J8) and the moving carriage unit represent various actuators and sensors provided in each joint or carriage unit 11.

[0094] The microcomputer 110 includes a storage unit 111, a communication unit 112, an I / O unit 113, and a control unit 115. The storage unit 111 is a storage device such as a ROM, RAM, hard disk, or flash memory, and stores various data and programs, which will be described later. The communication unit 112 is a communication unit that transmits and receives data to and from the outside, and communicates with external devices and systems. The I / O unit 113 performs input and output with external devices.

[0095] The control unit 115 is a control device such as a CPU, and performs processing by reading and executing various programs stored in the storage unit 111. For example, it issues operation commands to actuators provided in each joint or the moving cart unit, and performs calculation processing of the posture, etc. based on detection information from sensors provided in each joint or the moving cart unit.

[0096] In the figure, a power supply device such as a battery is omitted.

[0097] Furthermore, the functional blocks of the robot 100 are not limited to the configuration according to this embodiment, and may be configured as a system by executing some of the functions in an external information processing device or the like.

[0098] (Independent drive of the claws for opening and closing operations) In this embodiment, the output links 52L and 52R are not interlocked but are driven independently, so that the gripping position or the gripping center position can be changed when performing a gripping operation.

[0099] 4 is an explanatory diagram regarding the independent driving of the output links 52L, 52R. In the drawing, the right output link 52R extends relatively long, and the left output link 52L extends relatively short.

[0100] 5 is an explanatory diagram regarding changing the gripping position. As is clear from the figure, in the robot 100 in which the output links 52L and 52R are driven independently, the center position of the object 80 being gripped by the robot 100 is shifted to the side of the center plane that divides the robot 100 into left and right halves, or in the example shown in the figure, to the right as viewed from the robot 100.

[0101] With this configuration, the claws 54L, 54R attached to the output links 52L, 52R are also driven independently during opening and closing operations, so that the gripping position of the gripper 150 can be freely changed depending on the position of the object to be gripped.

[0102] According to such a configuration, it is possible to absorb positional deviations of the object to be grasped by changing the gripping position of the gripper 150, thereby realizing more efficient and stable gripping.

[0103] (Independent drive of claw bending joints) In this embodiment, claw bending joints (seventh and eighth joints (J7, J8)) are provided at the bases of the claws 54L, 54R, respectively, and these are driven independently.

[0104] 6 is an explanatory diagram regarding the independent driving of the claw bending joints (J7, J8). In the figure, the right claw 54R is bent by rotating slightly downward, and the left claw 54L is bent by rotating slightly upward.

[0105] With this configuration, in addition to the opening and closing movement of the claws 54L, 54R, it is possible to realize the bending movement of the claws 54L, 54R relative to the output links 52L, 52R or the claw connecting portions 53L, 53R.

[0106] 7 is an explanatory diagram (part 1) of the advantages of providing the claw bending joints (J7, J8). Note that in this diagram, the robot 100 is depicted as a schematic configuration for the purpose of explanation.

[0107] From the figure, it can be seen that without the claw bending joints (J7, J8), the reach range is a relatively limited spatial area (S1 in Figure (A)), but by providing the claw bending joints (J7, J8), the reachable spatial area is expanded (S2 in Figure (B)). In other words, it can be seen that the gripper 150 can achieve a variety of gripping postures, thereby expanding the possible gripping range.

[0108] 8 is an explanatory diagram (part 2) of another advantage of providing the claw bending joints (J7, J8). Note that in this diagram, the robot 100 is also depicted as a schematic configuration for the purpose of explanation.

[0109] 8(A), if the claw bending joints (J7, J8) were not present, it would be desirable to grip the object 80 with the claws 54L, 54R parallel to the object, and therefore the fourth joint would need to be bent at approximately 90 degrees. In this case, the distance from the center of the base end of the first link 21 to the object 80 is L1.

[0110] 8(B), when the claw bending joints (J7, J8) are provided, the claw bending joints (J7, J8) can be bent 90 degrees to make the claws 54L, 54R parallel to the object 80. In this case, the distance from the center of the base end of the first link 21 to the object 80 is L2.

[0111] At this time, the distance from the center of the base end to the object 80 is L1>L2. Therefore, by providing the claw bending joints (J7, J8), the moment at the base end of the articulated arm can be reduced. This makes it possible to prevent the robot 100 from tipping over when gripping an object, or from being damaged by the load.

[0112] FIG. 9 is an explanatory diagram (part 3) regarding another advantage of providing the claw bending joints (J7, J8). In this figure, two rectangular parallelepiped objects 81 and 82 are stacked vertically. In addition, although not shown, three or more objects are stacked in the depth direction. In this state, consider placing a new object 83 on top of object 82, aligning them.

[0113] In this case, with the gripper 150 according to this embodiment, first, the target object 83 can be placed on the target object 82 by shifting it slightly to the left, leaving a distance large enough for the right claw 54R to enter. Then, the right claw 54R can be rotated upward and retracted, and finally, the left claw 54L can be used to push the target object 83 horizontally from the left side.

[0114] With this configuration, it is possible to have only some of the claws act on the object to be grasped, enabling a variety of actions to be performed, such as pushing an object from the side. This allows tasks such as spreading out objects to be performed.

[0115] (nail shape) In this embodiment, the central axes of the claws 54L and 54R in the longitudinal direction are bent near the seventh or eighth joint portion.

[0116] FIG. 10 is an explanatory diagram (part 1) of the protection of a housing using a claw shape. As is clear from the figure, the longitudinal central axes of the claws 54L and 54R are bent toward the center of the connection with the claw connecting portions 53L and 53R near the claw bending joint portions (J7 and J8). In the example of the figure, the lowest end of the outer diameter line representing the eighth joint portion is located above the bottom surface of the left claw 54L by a distance d. In other words, the bottom surfaces of the claws 54L and 54R extend below (toward the floor surface) the surface of the housing of the main body (claw connecting portions 53L and 53R and gripper main body 51).

[0117] 11 is an explanatory diagram (part 2) of the protection of the housing using the claw shape. In the robot 100 in the posture shown in the figure with the second joint portion (J2) greatly bent, the claw 54L is disposed approximately parallel to the floor surface, but is bent toward the center of the connection portion with the claw connectors 53L and 53R near the claw bending joint portions (J7, J8). Therefore, the housing of the claw connector 53L does not come into contact with the floor surface.

[0118] According to this configuration, the floor-side end faces of the claws 54L, 54R extend closer to the floor than the surface of the housing of the main body (53L, 53R, or 51), so even if the gripper 150 is used near the floor, the housing of the main body does not come into direct contact with the floor, thereby protecting the housing of the main body (53L, 53R, or 51).

[0119] (1.2 Grip operation by gripper) Next, the gripping control operation by the gripper 150 or the robot 100 will be described.

[0120] 12 is an explanatory diagram showing a process of gripping an object 85 using the gripper 150 according to this embodiment. The figure is a plan view of the gripper 150. Please note that in the figure, the gripper 150 is simply illustrated as a gripper main body 51 and two claws (an output link 52, a claw connecting portion 53, and a claw 54).

[0121] As is clear from the figure, in the initial state, an object 85 is placed between the two jaws of the gripper 150 with its side parallel to the jaws (see the leftmost diagram). When the gripping process begins, the right jaw first moves inward until a reaction force from the object 85 is detected. If a reaction force is detected, the right jaw stops moving (see the second diagram from the left). Next, the left jaw moves inward until a reaction force from the object 85 is detected. If a reaction force is detected, the left jaw stops moving (see the second diagram from the right). In this state, the two jaws are in contact with the object 85. Finally, both jaws are controlled to generate stress until the target gripping force is reached (see the rightmost diagram).

[0122] With this configuration, it is possible to change the gripping position according to the position of the object by taking advantage of the fact that the claws can be opened and closed independently.

[0123] 12, the object 85 is placed with its side parallel to the claws. However, the robot 100 according to this embodiment can handle cases where the object to be grasped is placed at an angle to the contact surface with the claws.

[0124] 13 is an explanatory diagram showing the initial state of gripping when an object 86 is placed diagonally between the claws. Note that this figure is a plan view, and the robot 100 is shown in a schematic configuration. In this figure, the circle drawn below the gripper main body 51 indicates the multi-joint arm, and its center point represents the rotation center axis of the first joint unit (J1).

[0125] In the state shown in the figure, if both claws are moved inward to grip, there is a risk that the gripping will fail or that the gripping will not be in the desired manner. Therefore, in this embodiment, gripping is performed by utilizing the rotation of the first joint portion (J1).

[0126] FIG. 14 is an explanatory diagram showing a state in which the robot 100 is ready to grasp an object 86 placed diagonally between the claws. As is clear from the figure, in preparation for grasping the object 86, the first joint (J1) is rotated to make the robot 100 face the object 86. At this time, simultaneously with the rotation of the first joint, the claws are controlled in an interlocking manner to move to the right in the figure so as not to come into contact with the object 86. Thereafter, grasping is performed according to the process shown in FIG. 13. At this time, the interlocking of the claws and the first joint is achieved by solving inverse kinematics.

[0127] With this configuration, the first joint unit and the claw are controlled in conjunction with each other, so that the robot can be prepared to grasp without moving the carriage unit 11, the position of which is generally difficult to control accurately. This allows the robot to prepare to grasp with high precision.

[0128] (2. Variations) The present invention can be implemented in various modifications.

[0129] In the above-described embodiment, the claws 54L and 54R are tip members, but the present invention is not limited to such a configuration. Therefore, other members may be attached to the claws 54L and 54R.

[0130] 15 is a perspective view of a robot 200 according to a first modified example equipped with an additional gripping member. As is clear from the figure, the tips of the claws 54L and 54R of the robot 200 are provided with flat, plate-shaped second claws 55L and 55R that rotate or swing around axes parallel to the rotation central axes of the claw bending joints (J7 and J8).

[0131] This configuration also allows for flexible gripping.

[0132] 16 is a perspective view of a robot 300 according to a second modified example that includes an additional gripping member. As is clear from the figure, a short, thin plate-like gripping member 56R is provided at the tip of the right claw 54R and rotates or swings about an axis (J11) that is perpendicular to the rotation center axis of the claw bending joint (J7) and extends in the short side direction of the claw 54R, and a short, thin plate-like gripping member 56L is provided at the tip of the left claw 54L and rotates or swings about an axis (J12) in the longitudinal direction of the claw 54L and is perpendicular to the rotation center axis of the claw bending joint (J8).

[0133] With this configuration, two thin plate-like gripping members can be used to grasp an object by embracing or encircling it. Also, one gripping member can be used to pull the object toward you, while the other gripping member can support the bottom of the object.

[0134] 17 is a perspective view of a robot 400 according to a third modified example equipped with additional gripping members. As is clear from the figure, the tips of the jaws 54L, 54R of the robot 100 are provided with chuck hands 57L, 57R that rotate around axes parallel to the longitudinal axes of the jaws 54L, 54R.

[0135] With this configuration, it is possible to freely grasp an object.

[0136] In the above-described embodiment, the robot has a bilaterally symmetrical configuration, but the present invention is not limited to such a configuration. Therefore, an asymmetrical configuration may be adopted by making one claw 54 or output link 52 relatively long and the other relatively short.

[0137] In the above-described embodiment, the gripper 150 has been illustrated as having a minimum configuration of two claws, but the present invention is not limited to such a configuration. Therefore, for example, the number of claws may be three or more. Even in such a case, the gripping position can be changed depending on the object.

[0138] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Furthermore, the above embodiments can be combined as appropriate within the scope of not causing any contradiction. [Industrial Applicability]

[0139] The present invention can be used, for example, in industries that manufacture industrial robots. [Explanation of symbols]

[0140] 11 Bogie section 12 Omniwheel 21 Link 1 31 Second Link 41 Third Link 42 4th Link 51 Gripper body 52 output links 53 Claw connection part 54 Nails 55 Gripping member 56 Gripping member 57 Chuck Hand 100 robots 150 Gripper 200 Robot (first variant) 300 Robot (Second Variant) 400 Robot (Third Variant)

Claims

1. A gripper having a plurality of claws, each of which is opened and closed by a drive link provided between each of the claws and a main body, a closing drive unit that drives any one of the claws to perform a closing operation; a contact detection unit that detects whether the claws in the closing operation have come into contact with an object to be grasped; an operation stopping unit that stops operation of the claws when it is detected that the claws have come into contact with the object to be grasped; a repeat execution processing unit that repeatedly executes a series of processes by the closing drive unit, the contact detection unit, and the operation stopping unit until all of the claws have stopped; a gripping control unit that controls each of the claws to apply a target gripping force to the object to be gripped when all of the claws have stopped operating; a pawl joint portion is provided between each of the pawls and each of the drive links, the pawl joint portion causing each of the pawls to rotate about an axis parallel to the opening / closing direction relative to each of the drive links.

2. The gripper of claim 1 , wherein at each of the claw joints, the claws are driven independently of one another.

3. 3. The gripper of claim 1, wherein each of the drive links is driven independently of the others.

4. The gripper according to any one of claims 1 to 3, wherein the gripper has two claws, and the claws open and close while being parallel to each other.

5. The gripper according to any one of claims 1 to 4, wherein each of the drive links is driven by a linear motion mechanism.

6. The gripper according to claim 5 , wherein each of the linear motion mechanisms includes one of a ball screw or a slide screw and a linear guide.

7. The gripper according to any one of claims 1 to 6, further comprising a detection means between each of the claws and each of the drive links for detecting a force or moment acting on each of the claws.

8. The gripper according to any one of claims 1 to 6, further comprising an external force calculation unit that calculates an external force acting in the opening and closing directions of each of the claws.

9. The gripper according to any one of claims 1 to 8, wherein the end face of each of the claws on the floor side extends closer to the floor side than to the surface of the housing of the main body.

10. The gripper according to any one of claims 1 to 9, wherein each of the claws is provided with a gripping member that rotates relative to the claw about an axis parallel to the opening / closing direction.

11. A gripper according to any preceding claim, wherein each claw is provided with a gripping member that pivots relative to each claw about an axis perpendicular to the longitudinal axis of each claw.

12. The gripper according to any one of claims 1 to 9, wherein a chuck hand is attached to each of the jaws.

13. a gripper having a plurality of claws, each of which is opened and closed by a drive link provided between each of the claws and a main body, and a claw joint portion provided between each of the claws and each of the drive links for rotating each of the claws relative to each of the drive links about an axis parallel to the opening and closing direction; a moving mechanism; a plurality of drive joints disposed between the gripper and the movement mechanism; Equipped with The gripper further comprises: a closing drive unit that drives any one of the claws to perform a closing operation; a contact detection unit that detects whether the claws in the closing operation have come into contact with an object to be grasped; an operation stopping unit that stops operation of the claws when it is detected that the claws have come into contact with the object to be grasped; a repeat execution processing unit that repeatedly executes a series of processes by the closing drive unit, the contact detection unit, and the operation stopping unit until all of the claws have stopped; a gripping control unit that controls each of the claws to apply a target gripping force to the object to be gripped when all of the claws have stopped operating.

14. The robot according to claim 13 , wherein the movement mechanism is an omnidirectional moving carriage.

15. The robot of claim 14 , wherein the omnidirectional carriage is driven by omni-wheels.

16. The robot according to any one of claims 13 to 15, wherein the drive joint portion includes a first joint portion that rotates the gripper around a first axis that extends in a vertical direction.

17. The robot according to claim 16 , wherein the claws and the first joints are controlled to move together by solving inverse kinematics.

18. The robot according to any one of claims 13 to 17, wherein the claws of each claw joint portion are driven independently of each other.

19. The robot according to any one of claims 13 to 18, wherein each of the drive links is driven independently of the others.

20. The robot according to any one of claims 13 to 19, wherein the robot has two claws, and the claws open and close while being parallel to each other.

21. The robot according to any one of claims 13 to 20, wherein each of the drive links is driven by a linear motion mechanism.

22. 22. The robot according to claim 21, wherein each of the linear motion mechanisms includes one of a ball screw or a slide screw and a linear guide.

23. The robot according to any one of claims 13 to 22, further comprising a detection means between each of the claws and each of the drive links for detecting a force or moment acting on each of the claws.

24. The robot according to any one of claims 13 to 22, further comprising an external force calculation unit that calculates an external force acting in the opening and closing directions of each claw.

25. The robot according to claim 24 , wherein the external force calculation unit calculates the external force on the claw from a force or moment applied to each of the drive joints.

26. The robot according to any one of claims 13 to 25, wherein the end face of each of the claws facing the floor extends closer to the floor than to the surface of the housing of the main body.

27. a gripper having two claws, wherein drive links provided between each of the claws and a main body are driven by linear motion mechanisms to open and close the claws in a state parallel to each other, and a claw joint portion is provided between each of the claws and each of the drive links to rotate each of the claws relative to each of the drive links about an axis parallel to the opening and closing direction of the claws, and the claws are driven independently of each other at each of the claw joint portions, and the drive links are driven independently of each other; a movement mechanism that moves on a floor surface; a first link connected to the movement mechanism via a first joint and configured to rotate about a first axis extending in a vertical direction relative to the movement mechanism; a second link connected to the first link via a second joint and rotatable relative to the first link about a second axis perpendicular to the first axis; a third link connected to the second link via a third joint and sliding relative to the second link on an axis parallel to the second link; the gripper is connected to the third link via a fourth joint and rotates relative to the third link about a fourth axis parallel to the second axis; The gripper further comprises: a closing drive unit that drives any one of the claws to perform a closing operation; a contact detection unit that detects whether the claws in the closing operation have come into contact with an object to be grasped; an operation stopping unit that stops operation of the claws when it is detected that the claws have come into contact with the object to be grasped; a repeat execution processing unit that repeatedly executes a series of processes by the closing drive unit, the contact detection unit, and the operation stopping unit until all of the claws have stopped; a gripping control unit that controls each of the claws to apply a target gripping force to the object to be gripped when all of the claws have stopped operating.

Images