Holding piece

Abstract

A grip according to the present disclosure is provided with: a finger part (110); a rotating fingertip (120) which is provided at the tip of the finger part (110) and which is in direct contact with a target; a rotation motor (130) that serves as a rotation power generator for the rotating fingertip (120); and a finger expansion / contraction motor (140) serving as a power generator for moving the rotating fingertip (120) in the direction in which the finger (110) expands / contracts, the rotating fingertip (120) pressing / rotating the target as a pre-gripping preparation operation.

Description

Technical Field

[0001] The disclosed technology relates to a grip. Background Art

[0002] A gripper is a type of end effector installed at the end of a robot's arm. As its name suggests, a gripper is an end effector that is used to grip an object. The object gripped by the gripper is sometimes referred to as a target. Hereinafter, the gripped object will be referred to as a "target" in this specification.

[0003] Patent document 1 discloses a cable installation device and a robot for cable installation work. The cable installation device of Patent document 1 is a gripper. The gripper of Patent document 1 uses a suction cup to absorb a target cable placed on a workbench (sample table), slightly lifts it from the workbench and makes it easy to grip, and then grips it by clamping it with two fingers that move in parallel, more specifically, by two rotating bodies (gripping rollers) respectively provided at the ends of the two fingers.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2022 / 091246 Summary of the invention

[0007] Problems to be solved by the invention

[0008] When applying robot technology to "automation of cable installation work", it is best not to cause a cable grip failure. A cable grip failure may occur, for example, when the action of gripping the cable is started in a position and posture that is not easy to grip the cable (hereinafter referred to as "position and posture").

[0009] The problem of controlling a robot to a position and posture that is easy to hold a cable generally comes down to solving the problem of inverse kinematics. In the case of a human, it is possible to simply bring one's fingertips to the target position and posture without realizing it, but this is not easy for a robot. The program that controls the robot must solve the inverse kinematics of controlling the robot's end effector from the current position and posture to the target position and posture, and must also confirm that the robot will not interfere with other objects when controlling the robot's end effector to the target position and posture.

[0010] However, if one carefully observes the operation of people using chopsticks to grasp and pick up beans, before picking up the beans, they sometimes use chopsticks to slightly move the beans to a place where they are easy to hold, or slightly change the orientation to make it easier to grasp. Here, the action of changing the target to a position and posture that is easy to hold before grasping is called "pre-grasping preparatory action".

[0011] If the gripper installed at the end of the robot arm can perform the pre-grasping preparation action well, it is not necessary to solve the above-mentioned inverse kinematics or to perform interference checking. The purpose of the disclosed technology is to provide a gripper suitable for the pre-grasping preparation action. If the pre-grasping preparation action can be performed, it is not necessary to solve the inverse kinematics or to perform interference checking, and it is possible to transfer to the action of grasping the target.

[0012] Means for solving problems

[0013] The gripping device of the disclosed technology comprises: a finger; a rotating fingertip, which is arranged at the end of the finger and is in direct contact with the target; a rotation motor, which serves as a rotational power generator for the rotating fingertip; and a finger extension and retraction motor, which serves as a power generator for moving the rotating fingertip in the direction of finger extension and retraction, and the rotating fingertip performs a pressing and rotating action on the target as a preparatory action before gripping.

[0014] Effects of the Invention

[0015] Since the gripper of the disclosed technology has the above-mentioned structure, it is possible to perform preparatory actions before gripping, and it is possible to transfer to the action of grasping the target without solving inverse kinematics or performing interference checks. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is one of the external views showing the structure of the gripper 100 according to the first embodiment.

[0017] Figure 2 This is a second external view showing the structure of the gripper 100 according to the first embodiment.

[0018] Figure 3 This is an enlarged view showing a part of the structure of the gripper 100 according to the first embodiment.

[0019] Figure 4 This is a flowchart showing the control flow of the gripper 100 according to the first embodiment.

[0020] Figure 5 ( Figure 5 A and Figure 5 B) is an explanatory diagram showing a control example of the gripper 100 according to the first embodiment.

[0021] Figure 6 ( Figure 6 A. Figure 6 B and Figure 6 C) is one of the explanatory diagrams showing the “pressing and rotating action” which is a technical feature of the gripper 100 of the disclosed technology.

[0022] Figure 7This is the second explanatory diagram showing the “pressing and rotating action” which is a technical feature of the grip 100 of the disclosed technology.

[0023] Figure 8 This is one of the explanatory diagrams showing an example of the operation of the gripper 100 according to the second embodiment.

[0024] Fig. 9 This is the second explanatory diagram showing an example of the operation of the gripper 100 according to the second embodiment.

[0025] Fig.10 This is an explanatory diagram showing a structural example of simultaneously achieving the suction and rotation functions of the suction cup type rotating fingertip 120B constituting the gripper 100 according to the second embodiment. DETAILED DESCRIPTION

[0026] In order to make it easier for the robot arm to hold the target, it is also considered to work on the sample stage, such as vibrating the sample stage to keep the orientation of multiple targets consistent. The vibration of the sample stage is also an action to change the target to a position and posture that is easy to hold before holding it. Therefore, for a robot system including a sample stage, it can be said to be a broad pre-holding preparation action. This specification describes the technical features of the holding member 100 of the disclosed technology and clarifies the pre-holding preparation action performed by the holding member 100.

[0027] Implementation method 1.

[0028] Figure 1 FIG. 1 is one of the external views showing the structure of the gripper 100 according to Embodiment 1. Figure 1 As shown, the grip 100 of the first embodiment includes a finger portion 110 , a rotating fingertip 120 , a rotating motor 130 , a rotating gear group 132 , a finger extension motor 140 , a finger extension pinion 142 , and a finger extension rack 144 .

[0029] Figure 2 This is a second external view showing the structure of the gripper 100 according to the first embodiment. Figure 2 It is from Figure 1 The appearance of the handle 100 when viewed from different angles. Figure 1 Likewise, in Figure 2 4 , a finger portion 110 , a rotating fingertip 120 , a rotating motor 130 , a rotating gear group 132 , a finger extension motor 140 , a finger extension pinion 142 , and a finger extension rack 144 are shown.

[0030] <<Finger 110 Constituting Grip 100>>

[0031] The finger 110 constituting the grip 100 is, metaphorically speaking, a component equivalent to a human finger. In the technical field of robotics, a part equivalent to the finger 110 is sometimes referred to as a "claw". The finger 110 can be designed in size, shape, and material according to the purpose of use, specifically, according to the physical properties of the target. Figure 1 and Figure 2 Although two fingers 110 are shown in FIG. 1 , the disclosed technology is not limited thereto. The gripper 100 of the disclosed technology may also include three or more fingers 110 .

[0032] <<Rotating fingertip 120 constituting grip 100>>

[0033] The rotating fingertip 120 constituting the grip 100 is provided at the end of the finger 110 and is a component that directly contacts the target. The grip 100 of the disclosed technology is provided with a rotation motor 130 and a rotation gear group 132 to be described later, and can rotate the rotating fingertip 120 (see Figure 3 ). The rotational action of the rotating fingertip 120 can be used to send out the held cable Ca and to change the position and posture of the target as a preparatory action before holding. The action of sending out the held cable Ca is an action that envisions the process of engaging the cable Ca with the terminal (sometimes also referred to as a "connector engaging action"). In addition, in this specification, when it is said to be a specific name, that is, when it is emphasized that it is a proper noun, it is distinguished from a common noun by adding a symbol after the name, such as "cable Ca". In addition, in this specification, the cable Ca is specifically envisioned as a flexible flat cable.

[0034] The size and material of the rotating fingertip 120 can be designed according to the physical properties of the target. The rotating fingertip 120 can be made of silicon, for example.

[0035] <<Rotation motor 130 constituting gripper 100>>

[0036] The rotation motor 130 constituting the grip 100 is a component that serves as a rotational power generator for rotating the fingertip 120 . Figure 3 FIG. 1 is an enlarged view showing a part of the structure of the gripper 100 according to the first embodiment. Figure 3 2 shows a rotation motor 130 and a rotation gear train 132 to be described later. The rotating fingertip 120 is connected to the rotation motor 130 via the rotation gear train 132.

[0037] <<Rotation gear set 132 constituting the gripper 100>>

[0038] The rotating gear group 132 constituting the gripper 100 is a component composed of a plurality of gears. The rotating gear group 132 has a function of adjusting the torque and speed of rotating the rotating fingertip 120. The gear ratio of the rotating gear group 132 can be appropriately designed according to the characteristics of the rotating motor 130 and the physical properties of the target.

[0039] <<Finger extension and retraction motor 140 constituting grip 100>>

[0040] The grip 100 of the disclosed technology can perform movements similar to the extension and retraction of fingers. The finger extension motor 140 constituting the grip 100, if expressed metaphorically, is a component of a power generator that moves the rotating fingertip 120 in the direction of finger extension and retraction. In reality, the finger 110 does not need to be extended or retracted, but in this specification, the direction similar to the extension and retraction of the finger is referred to as the "direction of extension and retraction of the finger 110". In reality, if the finger 110 is considered to include the rotating fingertip 120, the finger 110 as a whole is extended or retracted. Figure 1 and Figure 2 As shown, the finger extension motor 140 moves the rotating fingertip 120 , the rotation motor 130 , and the rotation gear group 132 in the direction in which the finger 110 is extended or retracted via a finger extension pinion 142 and a finger extension rack 144 described later.

[0041] <<Finger extension pinion 142 and finger extension rack 144 constituting gripper 100>>

[0042] The finger extension pinion 142 and the finger extension rack 144 constituting the grip 100 are mechanisms for converting the rotational force of the finger extension motor 140 into linear motion. As the names indicate, the finger extension pinion 142 is a pinion, and the finger extension rack 144 is a rack. The finger extension motor 140, the finger extension pinion 142, and the finger extension rack 144 realize the linear motion of the rotating fingertip 120, the rotation motor 130, and the rotation gear group 132.

[0043] Figure 4 1 is a flow chart showing the control flow of the gripper 100 according to the first embodiment. Figure 4 As shown, the control process of the holding member 100 includes pressing the cable Ca with the rotating fingertip 120 (ST1), image processing of the cable Ca (ST2), calculating the position and posture of the cable Ca (ST3), calculating the holding angle difference (Δθ) of the cable Ca (ST4), action processing of rotating the cable Ca (ST5), and action processing of holding the cable Ca (ST6).

[0044] The control of the handle 100 is not shown in the figure, but is implemented by a controller. Specifically, the controller is composed of a processing circuit. Figure 4 Each processing step (ST1 to ST6) of the flowchart shown represents a processing step of the controller.

[0045] The pressing (ST1) of the rotating fingertip 120 on the cable Ca can be controlled in a manner called "pressing control" or "pressing control". Pressing control is known in the technical field of motor control as a control that combines torque control and speed control, and is a control that can suppress the instantaneous speed increase that occurs when switching from the previous position control to the torque control.

[0046] The image processing (ST2) of the cable Ca is a processing step for controlling the gripper 100 based on the real-time image obtained by the camera. Although not shown in the figure, the disclosed technology can also control the gripper 100 using the camera image in this way. The method of controlling the robot by performing image processing on the image information obtained from the camera and feeding back the result is sometimes called image feedback control.

[0047] Calculating the position and posture of the cable Ca (ST3) is a processing step for calculating the position and posture of the cable Ca as information for image feedback control. The position and posture of the cable Ca, if expressed using the terminology of modern control theory, can be said to be the state of the control object observed by the controller. Strictly speaking, the direct control object of the controller is the grip 100, but the cable Ca gripped by the grip 100 can also be considered as an indirect control object.

[0048] Calculating the grip angle difference (Δθ) of the cable Ca ( ST4 ) is a processing step of calculating the grip angle difference (Δθ) of the cable Ca as information for image feedback control.

[0049] Figure 5 ( Figure 5 A and Figure 5 B) is an explanatory diagram showing a control example of the gripper 100 according to the first embodiment. Figure 5 A represents the camera image at the current moment, and captures the position and posture of the cable Ca at the current moment. Figure 5 B is a diagram showing the target position and posture of the cable Ca. Figure 5 In the example shown, Figure 5 As shown in B, the target position and posture of the cable Ca is a position and posture where the length direction of the cable Ca is consistent with the up-down direction of the camera image. Figure 5 As shown in A, the grip angle difference (Δθ) of the cable Ca is defined as the difference between the current state and the target state.

[0050] In the field of control, subtracting a target state from the current state as a new state variable is frequently performed. In particular, in the case of nonlinear systems, a process called "linearization near the equilibrium point" or "linearization near the equilibrium state" is a common method. In the linearization near the equilibrium state, the error obtained by subtracting the target state (equilibrium state) from the current state is also used as a new state variable.

[0051] In addition, the grip angle difference (Δθ) of the cable Ca does not represent the entire error obtained by subtracting the target state from the current state. For example, if the cable Ca is regarded as a rigid body with 6 degrees of freedom located in a three-dimensional space, it is considered that there are 5 states in addition to the grip angle (θ) that can be directly grasped from the camera image. In this specification, as the most dominant state variable, only the grip angle difference (Δθ) of the cable Ca is shown, and in fact, other state variables, such as state variables related to position and state variables related to other angles, are also used.

[0052] The operation process of rotating the cable Ca (ST5) is a process step of realizing the "pressing and rotating operation" of the gripper 100 of Embodiment 1 in accordance with the pressing (ST1) of the cable Ca by the rotating fingertip 120. The pressing and rotating operation is an example of the preparatory operation before gripping.

[0053] Figure 6 ( Figure 6 A. Figure 6 B and Figure 6 C) is one of the explanatory diagrams showing the “pressing and rotating action” which is a technical feature of the gripper 100 of the disclosed technology. Figure 6 A represents the state of the gripper 100 when the controller implements the pressing (ST1) of the rotating fingertip 120 on the cable Ca. Figure 6 As shown in A, the pressing action on the cable Ca can be performed by one rotating fingertip 120 selected from a plurality of fingers. Figure 6 B shows the state of the gripper 100 when the controller performs the operation process (ST5) of rotating the cable Ca. At this time, the rotating fingertip 120 rotates the cable Ca so that the grip angle difference (Δθ) becomes 0 (zero). Figure 6 C shows the state of the gripper 100 when the controller performs the operation process (ST6) of gripping the cable Ca described later.

[0054] Figure 7 This is the second illustration of the "pressing and rotating action" which is the technical feature of the grip 100 of the disclosed technology. As described above, the disclosed technology includes a finger extension motor 140, a finger extension pinion 142, and a finger extension rack 144, so that the rotating fingertip 120 can be moved in the direction of the finger 110 extension. Figure 1 and Figure 2 In the embodiment, the rotating fingertip 120 is located in a position retracted from the end of the fingertip, but as Figure 6 and Figure 7 As shown, when performing the "pressing and rotating action", the rotating fingertip 120 is located at the end of the fingertip.

[0055] In addition, Figure 6 and Figure 7 In the figure, a suction cup type rotating fingertip 120B according to the second embodiment is shown instead of the rotating fingertip 120 according to the first embodiment. The details of the suction cup type rotating fingertip 120B are clarified in the second embodiment.

[0056] The operation process (ST6) of holding the cable Ca is a process step for realizing the main functional operation of the holding member 100. Figure 6 In C, the finger 110 is shown to sandwich the so-called edge portion of the cable Ca, but the disclosed technology is not limited thereto. The gripper 100 of the disclosed technology may be controlled to sandwich the so-called upper and lower surfaces of the cable Ca as when a person holds a ticket.

[0057] As described above, since the gripper 100 of the first embodiment has the above-mentioned structure, the pressing and rotating operation as the preparatory operation before gripping can be realized, and the operation of grasping the target can be shifted to without solving inverse kinematics or performing interference check.

[0058] In addition, the holding piece 100 of the disclosed technology may also be provided with a mechanism for assisting in grasping the target, such as an electromagnet portion (not shown) or a suction cup (not shown). If the mechanism for assisting in grasping the target is based on a principle different from the principle of grasping the target by the holding piece 100, it is considered to be able to cope with a variety of targets. Having an electromagnet portion is effective when the target has the property of being adsorbed on a magnet. The holding principle of the electromagnet portion is magnetic force, which is different from the principle of grasping the target by the holding piece 100. The holding principle of the suction cup is the differential pressure between the atmospheric pressure and the pressure generated by sucking air, which is different from the principle of grasping the target by the holding piece 100.

[0059] The second embodiment shows a suction cup type rotating fingertip 120B having both the function of the rotating fingertip 120 and the function of the suction cup.

[0060] Implementation method 2.

[0061] The gripper 100 of Embodiment 2 is a modified example of the gripper 100 of the disclosed technology. In Embodiment 2, the same reference numerals as those used in Embodiment 1 are used except for cases specifically described. In Embodiment 2, descriptions overlapping with those in Embodiment 1 are omitted as appropriate.

[0062] The gripper 100 of the second embodiment has a unique feature in that it has a suction cup type rotating fingertip 120B. The suction cup type rotating fingertip 120B is a component that has both the function of a rotating body (gripping roller) and the function of a suction cup. Figure 6 as well as Figure 7 As shown, the suction cup type rotating fingertip 120B is connected to one end of an air hose 150 for conveying sucked air in order to realize the function as a suction cup. Although not shown, the other end of the air hose 150 is connected to an air pump.

[0063] exist Figure 6 as well as Figure 7 , a suction cup type rotating fingertip 120B is provided instead of the rotating fingertip 120, but the disclosed technology is not limited thereto. The gripper 100 of the disclosed technology may also include both the rotating fingertip 120 and the suction cup type rotating fingertip 120B.

[0064] Figure 8 FIG. 1 is one of the explanatory diagrams showing an example of the operation of the gripper 100 according to the second embodiment. Figure 8 As shown, the gripper 100 of the disclosed technology may also be provided with a suction cup type rotating fingertip 120B in addition to the rotating fingertip 120 at the end of the finger portion 110. In this case, the pressing and rotating action is performed by the suction cup type rotating fingertip 120B. In the case of the suction cup type rotating fingertip 120B being provided, the gripper 100 of the disclosed technology is provided with a vertical movement mechanism (not shown) and a rotation mechanism (not shown) of the suction cup type rotating fingertip 120B that are independent of the mechanism for driving the rotating fingertip 120.

[0065] like Figure 8 As shown, when the suction cup type rotating fingertip 120B is additionally provided, the suction cup type rotating fingertip 120B can be set at a position equidistant from the two rotating fingertips 120. By setting the suction cup type rotating fingertip 120B at such a position, the cable Ca whose position and posture are adjusted by the pressing and rotating action can be easily grasped by the two rotating fingertips 120.

[0066] In the case where the suction cup type rotating fingertip 120B is additionally provided, the gripper 100 of the disclosed technology may not fix the suction cup type rotating fingertip 120B but allow the suction cup type rotating fingertip 120B to have a degree of freedom.

[0067] Fig. 9 This is the second explanatory diagram showing an example of the operation of the gripper 100 according to the second embodiment. Fig. 9 The illustrated suction cup type rotating fingertip 120B can be driven in parallel with the direction connecting the two rotating fingertips 120. Fig. 9As shown in the right figure of FIG. 1 , the drivable range of the suction cup type rotating fingertip 120B may include positions equidistant from the two rotating fingertips 120. By setting the drivable range in this way, the cable Ca whose position and posture are adjusted by the pressing and rotating action can be easily grasped by the two rotating fingertips 120.

[0068] Fig.10 1 is an explanatory diagram showing a structural example of realizing both the suction and rotation functions of the suction cup type rotating fingertip 120B constituting the gripper 100 of the second embodiment. Fig.10 As shown, the gripper 100 of the second embodiment may include an air hose 150, a bearing 160, and a connection portion 170 in addition to the rotation motor 130 and the rotation gear set 132. The structure of the bearing 160 and the connection portion 170 allows the rotation force of the rotation motor 130 to be transmitted while suction is performed by the air hose 150 without air leakage.

[0069] As described above, since the gripper 100 of the second embodiment has the above-mentioned structure, it can realize the pressing and rotating action as the preparatory action before gripping, similarly to the gripper 100 of the first embodiment, and can shift to the action of grasping the target without solving inverse kinematics or performing interference check.

[0070] Industrial Applicability

[0071] The disclosed technology can be applied to, for example, a robot that realizes automation of cable installation work, and has industrial applicability.

[0072] Description of symbols

[0073] 100: gripper, 110: finger, 120: rotating fingertip, 120B: suction cup type rotating fingertip, 130: rotating motor, 132: rotating gear set, 140: finger extension motor, 142: finger extension pinion, 144: finger extension rack, 150: air hose, 160: bearing, 170: connecting part.

Claims

1. A gripping member, comprising: Finger; a rotating fingertip, which is disposed at the end of the finger and is in direct contact with the target; a rotation motor which becomes a rotation power generator of the rotating fingertip; and The finger extension motor is a power generator for moving the rotating fingertip in the direction of the finger extension. The rotating fingertip performs a pressing and rotating action on the target as a preparatory action before grasping.

2. The grip according to claim 1, wherein: The handle also has: a rotating gear set that adjusts the torque and speed of rotating the rotating fingertip; and The finger extension pinion and the finger extension rack convert the rotational force of the finger extension motor into a linear motion.

3. A gripping member, comprising: Finger; A suction cup type rotating fingertip, which is arranged at the end of the finger and directly contacts the target; A rotation motor, which becomes a rotation power generator of the suction cup type rotating fingertip; A rotating gear set, which adjusts the torque and speed of rotating the suction cup type rotating fingertip; an air hose that delivers the sucked air; and A bearing and a connecting part, which simultaneously realizes the suction and rotation functions of the suction cup type rotating fingertip, The suction cup type rotating fingertip performs a pressing and rotating action on the target as a preparatory action before gripping.

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