Pocket-shaped actuator system, gripping device using the same, robot hand and method for using a robot hand

Abstract

Gripping device, with a gripping mechanism comprising a plurality of gripping elements (122, 123), wherein the gripping mechanism is configured to grip a workpiece by moving at least one of the gripping elements (122, 123); and a variety of pocket-shaped actuator systems with: a pocket-shaped actuator (1A, 1B; 11A-11D) with an airtight pocket element (2A, 2B; 12A-12D) made of a flexible film material and flowable particles (3A, 3B; 13A-13D) filled into the pocket element (2A, 2B; 12A-12D); a pocket element communication line (4A, 4B; 14A-14D) configured to communicate with an interior of the pocket element (2A, 2B; 12A-12D) of the pocket-shaped actuator (1A, 1B; 11A-11D); a negative pressure source communication line (5A, 5B; 15A-15D) configured to communicate with a negative pressure source (LP) that has a lower air pressure than the ambient air; a pressure source communication line (6A, 6B; 16A-16D) configured to communicate with a pressure source (HP) that has a higher air pressure than the ambient air; a switching mechanism (7A, 7B; 17A-17D) configured to perform switching between communication destinations of the pocket element (2A, 2B; 12A-12D) of the pocket-shaped actuator (1A, 1B; 11A-11D), such that the interior of the pocket element (2A, 2B; 12A-12D) communicates with the ambient air, the negative pressure source communication line (5A, 5B; 15A-15D), and the positive pressure source communication line (6A, 6B; 16A-16D) via the pocket element communication line (4A, 4B; 14A-14D); and a switching control section (8, 18) configured to control the switching between the communication destinations by the switching mechanism (7A, 7B; 17A-17D); wherein the gripping elements (122, 123) comprise respective contact gripping sections (126, 127) which are configured to grip the workpiece by contacting the workpiece; wherein at least one of the gripping elements (122, 123) is configured such that the contact gripping section (126, 127) and a base-end contact section (128, 129) are formed by respective pocket-shaped actuators of the pocket-shaped actuator systems, wherein the base-end contact section (128, 129) is arranged closer to a base end of the at least one of the gripping elements (122, 123) than the contact gripping section (126, 127), wherein the base-end contact section (128, 129) is configured such that it rests against the workpiece from the base end of the at least one of the gripping elements (122, 123).

Description

BACKGROUND OF THE INVENTION Technical field

[0001] The present invention relates to a pocket-shaped actuator system configured to actuate a pocket-shaped actuator, a gripping device utilizing the pocket-shaped actuator system, a robot hand containing the gripping device, and a method for using the robot hand. State of the art

[0002] A pocket-shaped actuator, a gripping device configured to grip a workpiece using the pocket-shaped actuator, and a method for gripping a workpiece using the gripping device are known (see JP 2011-230260A, JP 2014-8583A). For example, a pocket-shaped actuator (a contact section 6) is provided in JP 2011-230260A in each of the clamping sections 4b, 5b in the clamps 4, 5, wherein the clamping sections 4b, 5b are configured to clamp a workpiece 50, such that the pocket-shaped actuator serves as a contact section 6 that rests against the workpiece 50. The pocket-shaped actuator contains an inner packing 11 made of an elastic material and particles 12 that are filled into the inner packing 11.The pocket-shaped actuator (the attachment section 6) pressurizes the interior of the inner packing 11 and solidifies the particles 12, while the particles 12 are held in a specific shape, so that the attachment section 6 has a shape that conforms to the workpiece 50. The workpiece 50 is then clamped and held over the attachment sections 6 by the clamping sections 4b, 5b of the clamps 4, 5 (see summary, paragraphs

[0057] to

[0074] ). Fig. 15, Fig. 17 in JP 2011 - 230 260 A).

[0003] As such, the pocket-shaped actuators (the plant sections 6) hold the workpiece 50 by appropriately utilizing a state in which the interior of the inner packing 11 is set to atmospheric pressure, so that the particles 12 are fluid, and a state in which the interior of the inner packing 11 is depressurized, so that the particles 12 are solidified while the particles 12 are held in a certain shape.

[0004] Further state of the art is also known from JP 2013 - 86 185 A, DE 10 2009 038 275 A1, US 2012 / 0 253 516 A1, US 2016 / 0 114 485 A1 and JP 2003 - 305 678 A. SUMMARY OF THE INVENTION

[0005] In addition to a case in which the pocket-shaped actuators are used in such a way that, after deformation of the pocket-shaped actuators according to the shape of the workpiece to be gripped, the respective interior of the inner packaging is depressurized so that the pocket-shaped actuators are solidified, there is, however, a case in which the workpiece is elastically pressed by the use of the pocket-shaped actuators or the workpiece is to be moved by the use of the pocket-shaped actuators.

[0006] The present invention is carried out with regard to such a problem, and the object of the present invention is to provide a pocket-shaped actuator system that can achieve three states of a pocket-shaped actuator, namely an "elastically deformable state," a "soft and slightly inelastically deformable state," and a "hard and non-deformable state." Furthermore, the present invention is intended to provide a gripping device using the pocket-shaped actuator system, a robotic hand including the gripping device, and a use of the robotic hand.

[0007] (1) One aspect of the present invention for solving the above-mentioned problem is a gripping device according to claim 1 with a pocket-shaped actuator.

[0008] In the pocket-shaped actuator system, the interior of the pocket element filled with particles can communicate with the ambient air, the negative pressure source communication line, and the positive pressure source communication line via the pocket element communication line.

[0009] In a case where the interior of the pocket element communicates with the ambient air via the pocket element communication line, the pocket element will be slightly deformed when a workpiece rests against the pocket-shaped actuator (the pocket element) and a force is exerted on the pocket-shaped actuator (the pocket element), causing the particles filled into the pocket element to flow. This can slightly deform the entire pocket-shaped actuator.

[0010] Meanwhile, in a case where the interior of the pocket element communicates with the vacuum source communication line via the pocket element communication line, the vacuum source depressurizes the interior of the pocket element, causing the pocket element to be compressed by atmospheric pressure outside of it. This compresses the particles inside the pocket element, forcing them into close contact and making them difficult to flow. Consequently, the pocket-shaped actuator is not easily deformed.

[0011] Meanwhile, in a case where the interior of the pocket element communicates with the overpressure source communication line via the pocket element communication line, the pocket element is pressurized from within by the overpressure source communicating with the overpressure source communication line, causing the pocket element to inflate like a balloon. The workpiece or similar object to which the pocket element rests can then be elastically compressed, or the workpiece or similar object to which the pocket element rests can be moved by a contact force from the pocket-shaped actuator (the pocket element). Alternatively, the workpiece can be gripped elastically.

[0012] This means that, from this perspective, the pocket-shaped actuator system is a system that can achieve three states of the pocket-shaped actuator, i.e., an "elastically deformable state (at the time of communication with the overpressure source communication line)," a "soft and slightly inelastically deformable state (at the time of communication with the ambient air)," and a "hard and non-deformable state (at the time of communication with the underpressure source communication line)."

[0013] The pocket-shaped actuator system can be used in various ways, but for example, it can be used in the following manner. That is, in a state where the interior of the pocket element communicates with the ambient air, the pocket-shaped actuator, when brought into contact with the workpiece or similar object, can be easily deformed to conform to the shape of the workpiece or similar object against which the pocket-shaped actuator rests.

[0014] Considering this, in a state where the interior of the pocket element temporarily communicates with the ambient air, the pocket-shaped actuator is brought into contact with the workpiece or the like, so that the pocket-shaped actuator has a shape along the workpiece or the like. Furthermore, in a case where the switching mechanism is controlled such that the interior of the pocket element communicates with the vacuum source communication line in order to become depressurized, the pocket-shaped actuator retains the shape along the form of the workpiece or the like against which the pocket-shaped actuator rests, and the pocket-shaped actuator enters a non-deformable state. Accordingly, for example,In a gripping device to which the pocket-shaped actuator system is attached, it is possible to grip the workpiece or similar object by using the pocket-shaped actuator, which is deformed to follow the shape of the workpiece or similar object.

[0015] Furthermore, in a state where the interior of the pocket element is temporarily exposed to the ambient air, the pocket-shaped actuator is brought into contact with the workpiece or similar object, so that the pocket-shaped actuator conforms to the shape of the workpiece or similar object. The switching mechanism is then controlled so that the interior of the pocket element communicates with the overpressure source communication line in order to be pressurized. In this case, the workpiece or similar object to which the pocket-shaped actuator rests can be elastically pressed by the pocket-shaped actuator. Alternatively, the workpiece or similar object to which the pocket-shaped actuator rests can be moved by being elastically pressed by the pocket-shaped actuator. Accordingly, for example,The gripping device to which the pocket-shaped actuator is attached can grasp the workpiece or the like while the workpiece or the like is elastically pressed, and the gripping device can move the workpiece or the like to which the pocket-shaped actuator rests by pressing on the workpiece or the like.

[0016] Examples of a film material that exhibits flexibility and forms the airtight pocket element in the pocket-shaped actuator include, for example, elastic and airtight rubber materials such as natural rubber and synthetic rubber, e.g., styrene-butadiene rubber, nitrile rubber, fluororubber, and silicone rubber; films made of synthetic resin such as polyethylene, polypropylene, polyamide, polyimide, and polytetrafluoroethylene; composite materials made of a synthetic resin film and a metal film such as aluminum foil; etc.

[0017] Furthermore, examples of the free-flowing particles that are filled into the pocket element can include sand, salt particles, sugar particles, aluminum oxide particles, ceramic particles such as silicon dioxide particles, glass particles, synthetic resin particles (pellets), foaming resin particles such as styrene foam particles, metal particles such as iron particles, aluminum particles and copper particles, and mixtures thereof.

[0018] Furthermore, the pocket-shaped actuator can be configured so that the pocket element is brought into direct contact with the workpiece, but the pocket-shaped actuator can also be configured so that an outside of the pocket element is covered with an outer pocket element that serves as an outer shell, similar to JP 2011 - 230 260 A and so on.

[0019] The vacuum source should have a mechanism that can reduce the pressure inside the pocket element of the pocket-shaped actuator via the vacuum source communication line, so that the pressure inside the pocket element becomes lower than the outside air (atmospheric pressure). The vacuum source could be, for example, a vacuum pump or a vacuum tank connected to a vacuum pump.

[0020] The overpressure source should have a mechanism capable of pressurizing the interior of the pocket element of the pocket-shaped actuator via the overpressure communication line, so that the pressure inside the pocket element becomes higher than that of the ambient air (atmospheric pressure). Examples of overpressure sources include a compressor, a compressor with an overpressure gas reserve tank, an overpressure gas reserve tank connected to a compressor, a factory air line, an overpressure gas cylinder such as a compressed air cylinder or a nitrogen gas cylinder, etc. Depending on the atmospheric pressure of the gas in the overpressure source, a pressure regulating element such as a pressure regulator (a pressure control device) may be provided in the overpressure source communication line.Furthermore, the switching mechanism is configured to control the pocket element communication line, allowing it to communicate with the negative pressure source communication line, the positive pressure source communication line, and the ambient air. The switching mechanism can, for example, be an electromagnetic four-way switching valve connected to the negative pressure source communication line, the positive pressure source communication line, the ambient air, and the pocket element communication line. Alternatively, the switching mechanism can utilize a variety of electromagnetic switching valves to control the pocket element communication line, enabling it to communicate with the negative pressure source communication line, the positive pressure source communication line, and the ambient air.

[0021] In the gripping device, at least one of the gripping elements of the gripping mechanism comprises the contact gripping section and the base-end contact section, each formed by the pocket-shaped actuator of the pocket-shaped actuator system. As described above, the pocket-shaped actuator system can achieve the three states of the pocket-shaped actuator, i.e., the "elastically deformable state (at the time of communication with the positive pressure source communication line)," the "soft and slightly inelastically deformable state (at the time of communication with the outside air)," and the "hard and non-deformable state (at the time of communication with the negative pressure source communication line)."

[0022] For this reason, the gripping device can bring the contact gripping section formed by the pocket-shaped actuator into contact with the workpiece to be gripped, in a contact state selected from three states: the "elastically deformable contact state," the "soft and slightly inelastically deformable contact state," and the "hard and non-deformable contact state." This can further increase the degrees of freedom of the workpiece's gripping state through the contact gripping sections of the gripping elements and achieve a more suitable gripping of the workpiece.

[0023] Furthermore, in the gripping device, at least one of the gripping elements includes, in addition to the contact gripping section formed by the pocket-shaped actuator, the base-end contact section, which is formed by the pocket-shaped actuator and is arranged closer to the base end than the contact gripping section. The base-end contact section is configured such that it rests against the workpiece from the base end of the gripping element. For this reason, it is possible to further increase the degrees of freedom of the workpiece's gripping state and achieve a more suitable gripping of the workpiece by bringing the base-end contact section (the pocket-shaped actuator) into any one of the three states.

[0024] Furthermore, in the gripping device, the base-end contact section contained in at least one of the gripping elements rests against the workpiece from the base end of the gripping element. Accordingly, in a state in which the interior of the pocket element of the pocket-shaped actuator, which forms the base-end contact section, is caused to communicate with the ambient air, the base-end contact section (the pocket-shaped actuator) is brought into contact with the workpiece or the like, so that the base-end contact section (the pocket-shaped actuator) has a shape along the workpiece or the like.The switching mechanism is then controlled so that the interior of the pocket element communicates with the overpressure source communication line, so that it is pressurized, causing the pocket element to inflate, and in this state the base end-side attachment section can be caused to elastically press the workpiece to which the base end-side attachment section rests or to move the workpiece by pressing.

[0025] (2) The gripping device described in (1) can be configured such that the number of pocket-shaped actuator systems provided in the gripping device is twice as many or more than the number of gripping elements and that corresponding contact gripping sections and corresponding base-end contact sections of the gripping elements are formed by corresponding pocket-shaped actuators of the pocket-shaped actuator systems.

[0026] In the gripping device, all gripping elements contain corresponding contact gripping sections and corresponding base-end contact sections, each formed by the pocket-shaped actuator.

[0027] For this reason, the gripping device uses the contact gripping sections formed by the pocket-shaped actuator and the contact sections formed by the base-end actuator for the workpiece to be gripped, so that it is possible to further increase the degree of freedom of the gripping state of the workpiece and to achieve a more suitable gripping of the workpiece.

[0028] (3) Another aspect of the present invention is a robot hand comprising a body of the robot hand; the gripping mechanism of the gripping device described in (1) or (2), wherein the gripping mechanism is arranged in a distal end section of the body of the robot hand; and a force sensor configured to detect an external force applied to the gripping elements of the gripping mechanism.

[0029] The robot hand also contains the force sensor. Accordingly, when a predetermined process is performed on the workpiece, such that the workpiece is gripped by the gripping mechanism and moved by the robot hand, any external force exerted on the workpiece by the gripping elements can be detected by the force sensor via the gripping device. Therefore, the process can be stopped if an unusual external force is exerted on the workpiece due to an unsuitable gripping position. In this way, an anomaly in the process affecting the workpiece can be detected.

[0030] Furthermore, in the robot hand, the gripping section of the gripping element within the gripping mechanism is formed by the pocket-shaped actuator. Accordingly, it is possible to perform a flexible process on the workpiece by correctly utilizing the three contact states mentioned above. In addition, at least one of the gripping elements in the robot hand contains the base-end contact section, which is formed by the pocket-shaped actuator. Therefore, it is possible to perform another flexible process on the workpiece by correctly utilizing the three contact states mentioned above for the base-end contact section. This further flexible process could, for example, involve rotating the workpiece or similar operations.

[0031] (4) The robot hand described in (3) can be configured such that the force sensor is a six-axis force sensor located between the body of the robot hand and the gripping mechanism.

[0032] The robot hand also incorporates a six-axis force sensor. Accordingly, when a predetermined process is performed on the workpiece, it is possible to detect any external force exerted on the workpiece gripped by the robot hand by dissecting the external force across six axes. Therefore, even if an unusual external force is detected midway through the process due to an unsuitable gripping position, it is possible to better understand the external force and take more appropriate action.

[0033] (5) Another aspect of the present invention is a use of the robot hand as described in (3) or (4). The use comprises: a gripping step of grasping the workpiece by the contact gripping sections of the gripping elements of the gripping mechanism; an insertion step of inserting the gripped workpiece into an insertion hole of an insertion target workpiece; and a release step of releasing the workpiece inserted into the insertion hole from gripping by the gripping elements. The insertion step comprises: a movement step of moving the gripping mechanism grasping the workpiece towards the insertion hole of the insertion target workpiece along a hole axis of the insertion hole, while an external force exerted on the gripping mechanism via the workpiece is detected by the force sensor;a monitoring step for an unusual external force, in which the motion step monitors whether an unusual external force becomes greater than a predetermined threshold for an unusual external force, wherein the unusual external force acts along a direction different from the direction of an external force in the feed direction, and wherein the external force in the feed direction acts along a direction opposite to the feed direction of the gripping mechanism; a motion stop step to temporarily stop the motion in the motion step if the unusual external force becomes greater than the threshold for the unusual external force;a posture change step for changing the posture of the workpiece such that, after the motion has been stopped in the motion stop step, the pocket element of at least one of the pocket-shaped actuators forming the contact gripping sections or the base-end contact sections in contact with the workpiece is inflated by causing the interior of the pocket element to communicate with the overpressure source communication line via the pocket element communication line, so that when the motion is restarted in the feed direction, the magnitude of any unusual external force exerted on the gripping elements via the workpiece after the restart is smaller than the magnitude of the unusual external force before the stop; a re-gripping step for the gripping elements to re-grip the workpiece;and a restart step to restart the movement in the feed direction, whereby the movement is temporarily stopped.

[0034] Even when using the robot hand, and even in cases where an unusual external force is exerted on the workpiece midway through the process due to an unsuitable gripping position or similar issue, changing the gripping position allows the workpiece to be inserted appropriately into the entry hole of the target workpiece. This reduces the likelihood of the workpiece failing to enter the entry hole.

[0035] (6) Furthermore, in the uses described in (5), at least one of the pocket elements forming the contact sections can be inflated during the step of changing position, so that the workpiece is moved towards the distal end sides of the gripping elements provided with the base end contact sections.

[0036] When using the robot hand, during the posture change step, the pocket-shaped actuator forming the base-end contact section inflates, moving the workpiece to a distal end of the gripper equipped with the base-end contact section. This allows the workpiece posture to be changed more easily in some cases, resulting in a smaller magnitude of the abnormal external force after restart than the magnitude of the abnormal external force before contact. With such a configuration, the workpiece can be adequately inserted into the insertion hole of the target workpiece over a wider range, further reducing the likelihood of workpiece insertion failure.

[0037] It should be noted that the movement of the workpiece towards the distal end of the gripping element includes a case in which the workpiece is moved translationally towards the distal end of the gripping element, a case in which the workpiece is moved rotationally such that a part of the workpiece against which the base-end contact section rests is moved towards the distal end of the gripping element, and a case that includes both the translational movement and the rotational movement. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying figures, in which similar numerals denote similar elements and wherein: Fig. Figure 1 refers to embodiments 1 and 2 and is an illustrative view showing a robot hand with a distal end section equipped with a clamping mechanism of a clamping device using a pocket-shaped actuator system; Fig. Figure 2 refers to embodiment 1 and is an illustrative view of the clamping device using the pocket-shaped actuator system; Fig. 3 refers to embodiment 1 and is an explanatory view showing a state prior to the insertion of a first connecting piece gripped by the clamping device into an insertion hole along the axis of a second connecting piece; Fig. Figure 4 refers to embodiment 1 and is an illustrative view showing a state after the insertion of the first connecting piece gripped by the clamping device into the insertion hole of the second connecting piece; Fig. 5 refers to embodiment 1 and is a flowchart showing the sequence of a process for the robot hand in which the first connector is gripped by the clamping device and the first connector is inserted into the insertion hole of the second connector; Fig. Figure 6 relates to embodiment 1 and is an illustrative view showing a state in which the first connecting piece, which is gripped by the clamping device, is inserted into the insertion hole of the second connecting piece in a state in which the axis of the clamping mechanism has an offset angle to the axis of the second connecting piece and the movement of the first connecting piece is stopped due to the detection of an unusual external force; Fig. 7 refers to embodiment 1 and is an explanatory view showing a state in which the first connecting piece gripped by the clamping device is pressed and moved by a contact gripping section communicating with an overpressure; Fig. Figure 8 refers to embodiment 1 and is an illustrative view showing a state in which the first connecting piece that has been moved is again gripped by the clamping device and the insertion of the first connecting piece into the insertion hole of the second connecting piece is resumed; Fig. Figure 9 refers to embodiment 2 and is an illustrative view of the clamping device using the pocket-shaped actuator system; Fig. Figure 10 refers to embodiment 2 and is an explanatory view showing a state prior to the insertion of the first connecting piece gripped by the clamping device into the insertion hole along the axis of the second connecting piece; Fig. Figure 11 refers to embodiment 2 and is an illustrative view showing a state after the insertion of the first connecting piece gripped by the clamping device into the insertion hole of the second connecting piece; Fig. Figure 12 is a flowchart showing the sequence of a process for the robot hand according to embodiment 2, in which the first connecting piece is gripped by the clamping device and the first connecting piece is inserted into the insertion opening of the second connecting piece; Fig. Figure 13 relates to embodiment 2 and is an illustrative view showing a state in which the first connecting piece, which is gripped by the clamping device, is inserted into the insertion hole of the second connecting piece in a state in which the axis of the clamping mechanism has an offset angle to the axis of the second connecting piece and the movement of the first connecting piece is stopped due to the detection of an unusual external force; Fig. Figure 14 relates to embodiment 2 and is an illustrative view showing a state in which the first connecting piece gripped by the clamping device is pressed and moved by the contact gripping section communicating with an overpressure; and Fig. Figure 15 refers to embodiment 2 and is an illustrative view showing a state in which the first moving connecting piece is again gripped by the clamping device and the insertion of the first connecting piece into the insertion opening of the second connecting piece is resumed. DETAILED DESCRIPTION OF THE EXECUTION FORMS Execution form 1

[0039] With reference to the Fig. In sections 1 to 8 below, the first embodiment of the present invention is described. Fig. Figure 1 shows a robot hand 30 according to embodiment 1, and Fig. Figure 2 shows a configuration of a clamping device 20 using the pocket-shaped actuator systems 0A, 0B.

[0040] As in Fig. As shown in Figure 1, the robot hand 30 of embodiment 1 includes a clamping mechanism 20S of the clamping device 20. The clamping mechanism 20S is located in a distal end section 31S (the left side in Fig. 1) A force sensor 40 is provided for a robot hand body 31. Among them, the robot hand body 31 is a so-called articulated robot, and the position and movement of each part of the robot hand body 31 is controlled by a robot hand control unit 32. Meanwhile, the clamping mechanism 20S of the clamping device 20 is an electric gripper configured to grip a workpiece (e.g., a first connecting piece C1) as described later.

[0041] As in Fig. As shown in Figure 2, the clamping mechanism 20S of the clamping device 20 consists of a clamping body section 21 and a pair of gripping elements 22, 23 extending from the clamping body section 21. The gripping elements 22, 23 are configured to be slidably movable within the clamping body section 21, and the operations for gripping and releasing a workpiece are controlled by a clamping body control section 20C. It should be noted that, as indicated by arrows in Figure 2, the clamping mechanism 20S of the clamping device 20 consists of a clamping body section 21 and a clamping body section 21. The gripping elements 22, 23 are configured to be slidably movable within the clamping body section 21, and the operations for gripping and releasing a workpiece are controlled by a clamping body control section 20C. Fig. As specified in Figure 2, among the movements of the gripping elements 22, 23, the directions in which the gripping elements 22, 23 approach each other are designated as gripping sides 20A and the directions in which the gripping elements 22, 23 are separated from each other are designated as release sides 20B. That is, when the gripping elements 22, 23 are moved towards the gripping sides 20A, the clamping mechanism 20S can grip a workpiece, and when the gripping elements 22, 23 are moved towards the release sides 20B, the clamping mechanism 20S can release the workpiece.

[0042] The force sensor 40 is a six-axis force sensor that can detect translational forces in three directions X, Y, and Z, which are translational directions, and moments in three directions Rx, Ry, and Rz, which are rotational directions about the respective axes. In embodiment 1, as shown in Fig. As shown in Figure 2, the clamping mechanism 20S is attached to the six-axis force sensor 40 such that one sliding direction of the gripping elements 22, 23 is in the X direction and another direction is along an axis 20X of the clamping mechanism 20S in the Z direction. Note that a direction perpendicular to the X and Z directions is the Y direction, a direction rotating about the Z direction (a Z-axis, the axis 20X of the clamping mechanism 20S) is the Rz direction, a direction rotating about the X direction (an X-axis) is the Rx direction, and a direction rotating about the Y direction (a Y-axis) is the Ry direction. Sensor output information from the force sensor 40 is input into the clamping element control section 20C.

[0043] For this reason, the force sensor 40 can detect an unusual external force if, when the gripping elements 22, 23 grasp a workpiece (e.g., the first connecting piece C1) and perform a predetermined operation, the gripped workpiece, the gripping elements 22, 23, or the clamping body section 21 are in contact with other elements and an unusual external force is exerted on the workpiece, the gripping elements 22, 23, or the clamping body section 21. Accordingly, if the force sensor 40 detects an unusual external force, a fault correction can be performed on the workpiece, such as stopping the movement of the workpiece by the robot hand body 31. Furthermore, the force sensor 40 is a six-axis force sensor, and therefore, at the time a predetermined process is performed on a workpiece, the force sensor 40 can detect an external force acting on the workpiece or similar.The force exerted on a gripping mechanism can be identified more precisely by dissecting the external force onto the respective axes.

[0044] The clamping device 20 is described with reference to Fig. 2 described in more detail. The gripping elements 22, 23 of the clamping mechanism 20S consist of the respective clamping jaw elements 24, 25 and the respective contact gripping sections 26, 27. The clamping jaw elements 24, 25 are made of metal and have an L-shaped cross-section. The clamping jaw elements 24, 25 are arranged opposite each other. The contact gripping sections 26, 27 are provided in the clamping jaw elements 24, 25. The clamping jaw elements 24, 25 contain corresponding base sections 24A, 25A, which are partially supported by the clamping body section 21, and corresponding clamping jaw sections 24B, 25B, which extend from the base sections 24A, 25A along the axis 20X. The contact gripping sections 26, 27 are arranged on the respective inner surfaces of the clamping jaw sections 24B, 25B.For this reason, in a case where a workpiece is gripped by the gripping elements 22, 23 of the clamping mechanism 20S, the workpiece is gripped in such a way that the workpiece rests against the contact gripping sections 26, 27.

[0045] The gripping sections 26, 27 are pocket-shaped actuators 1A, 1B within the pocket-shaped actuator systems 0A, 0B. The pocket-shaped actuators 1A, 1B (the gripping sections 26, 27) consist of the corresponding pocket elements 2A, 2B and the corresponding particles 3A, 3B. The pocket elements 2A, 2B are soft, easily deformable, and airtight. The particles 3A, 3B are free-flowing and filled into the pocket elements 2A, 2B. In embodiment 1, the pocket elements 2A, 2B are made of nitrile rubber (NBR), and the particles 3A, 3B are made of aluminum oxide particles. The pocket-shaped actuators 1A, 1B are operated by an actuator control unit 9, which is connected to a negative pressure source LP and a positive pressure source HP.

[0046] More precisely, the interior of each pocket element 2A, 2B of the pocket-shaped actuators 1A, 1B is connected to the respective switching mechanisms 7A, 7B via the respective pocket element communication lines 4A, 4B. The switching mechanisms 7A, 7B are connected to the ambient air AT, to the negative pressure source LP via corresponding negative pressure source communication lines 5A, 5B, and to the positive pressure source HP via corresponding positive pressure source communication lines 6A, 6B. Based on control by a switching control section 8, the interior of the pocket elements 2A, 2B can be switched to the ambient air AT, the negative pressure source, or the positive pressure source HP via corresponding pocket element communication lines 4A, 4B. The switching control section 8 is connected to the clamping element control section 20C.The switching control section 8 performs drive controls on the robot hand body 31, on the clamping body section 21 and on the pocket-shaped actuators 1A, 1B through cooperation of the robot hand operating device 32, the clamping body control section 20C and the switching control section 8, so that the clamping body section 21 can grip a workpiece appropriately and perform a predetermined operation.

[0047] In a case where the respective interiors of the pocket elements 2A, 2B of the pocket-shaped actuators 1A, 1B communicate with the ambient air AT via the pocket element communication lines 4A, 4B, the interior of the pocket elements 2A, 2B is also equal to the external air pressure (atmospheric pressure), so that the particles 3A, 3B filled into the pocket elements 2A, 2B can flow easily. Accordingly, when the workpiece rests against the pocket-shaped actuators 1A, 1B (the pocket elements 2A, 2B) and a force is exerted on the pocket-shaped actuators 1A, 1B (the pocket elements 2A, 2B), the pocket elements 2A, 2B are slightly deformed, so that the particles 3A, 3B filled into the pocket elements 2A, 2B can flow. This means that the pocket elements 2A, 2B (the pocket-shaped actuators 1A, 1B) transition into a soft and slightly inelastic deformable state.

[0048] Meanwhile, when the interior of the pocket elements 2A, 2B communicates with the vacuum source communication lines 5A, 5B via the pocket element communication lines 4A and 4B, respectively, the interior of the pocket elements 2A, 2B is depressurized by the vacuum source LP, which communicates with the vacuum source communication lines 5A, 5B. This causes the pocket elements 2A, 2B to be compressed by the atmospheric pressure outside the pocket elements 2A, 2B. As a result, the particles 3A, 3B contained within the pocket elements 2A, 2B are compressed, causing them to come into close contact and become difficult to flow. Consequently, the pocket elements 2A, 2B (the pocket-shaped actuators 1A, 1B) enter a rigid and non-deformable state.

[0049] Meanwhile, when the interior of the pocket elements 2A, 2B communicates with the overpressure source communication lines 6A, 6B via the pocket element communication lines 4A and 4B respectively, the pocket elements 2A, 2B are pressurized from the inside by the overpressure source HP, which communicates with the overpressure source communication lines 6A, 6B, causing the pocket elements 2A, 2B to inflate like a balloon. This allows the pocket elements 2A, 2B to be brought into an elastically deformable state. This allows, for example, the workpiece or similar adjacent to the pocket elements 2A, 2B (the pocket-shaped actuators 1A, 1B) to be elastically pressed, or the workpiece or similar against which the pocket elements 2A, 2B (the pocket-shaped actuators 1A, 1B) are in contact can be moved by the contact forces of the pocket elements 2A, 2B (the pocket-shaped actuators 1A, 1B). Alternatively, the workpiece can be gripped elastically.

[0050] As such, the pocket-shaped actuator systems 0A, 0B of embodiment 1 can bring the pocket-shaped actuators 1A, 1B into three states, i.e., the "elastically deformable state," the "soft and slightly inelastically deformable state," and the "hard and non-deformable state." It should be noted that in the present embodiment, the negative pressure source LP, which is connected to the negative pressure source communication lines 5A, 5B, is formed by a vacuum reserve tank VT and a vacuum pump VP connected thereto. Furthermore, the positive pressure source HP, connected to the positive pressure source communication lines 6A, 6B, consists of a positive pressure reserve tank HT and a compressor CP connected thereto. However, the vacuum pump VP can be connected directly to the negative pressure source communication lines 5A, 5B. The compressor CP can also be connected directly to the positive pressure source communication lines 6A, 6B.It should be noted that using the vacuum reserve tank VT or the positive pressure reserve tank HT offers the advantage of limiting pressure fluctuations. Alternatively, a positive pressure gas cylinder, such as a nitrogen gas cylinder, can be used instead of the compressor CP.

[0051] Furthermore, in the clamping device 20 of embodiment 1, the contact gripping sections 26, 27 of the clamping mechanism 20S are formed by the pocket-shaped actuators 1A, 1B of the pocket-shaped actuator systems 0A, 0B, so that the contact gripping sections 26, 27 can reach the three states mentioned above. For this reason, in the clamping device 20, the contact gripping sections 26, 27 can be brought into contact with the first connecting piece C1 to be gripped by selecting one of the three states mentioned above, thereby increasing the degree of freedom of a gripping state of the first connecting piece C1 and gripping the first connecting piece C1 more appropriately. In addition, in embodiment 1, the contact gripping sections 26, 27 are both the pocket-shaped actuators 1A, 1B and can select any of the three states mentioned above.This further increases the degree of freedom of the gripping state of the first connecting piece C1 by the gripping elements 22, 23 and achieves a more suitable gripping of the first connecting piece C1.

[0052] Next, a workpiece process is described in which the robot hand 30, including the clamping device 20, is used with reference to a process of gripping the first connecting piece C1 as a workpiece by the clamping mechanism 20S of the robot hand 30 and inserting the first connecting piece C1 into an insertion hole C2H of a second connecting piece C2 of an object OJ as the insertion target workpiece (see the Fig. 3, Fig. 4 and Fig. 5) It should be noted that the object OJ is the target workpiece for introduction and that the second connecting piece C2 is positioned at a predetermined location.

[0053] First, in a gripping step S1, a section C1G of the first connector C1 is gripped by the gripping elements 22, 23 of the clamping mechanism 20S. More precisely, the gripping elements 22, 23 are moved to the release sides 20B (outer sides) (step S11), and the interior of the attachment gripping sections 26, 27 (the pocket elements 2A, 2B) is opened to the ambient air AT (step S12). Simultaneously, the clamping mechanism 20S is moved into a gripping position for the first connector C1 (step S13). More precisely, the clamping mechanism 20S is moved by the robot hand body 31, and the clamping mechanism 20S is positioned so that the section C1G of the first connector C1 is placed between two gripping elements 22, 23.In this state, the two gripping elements 22, 23 are moved to the gripping sides 20A (inner sides), and the section C1G of the first connecting piece C1 to be gripped is clamped between the system gripping sections 26, 27 until the gripping elements 22, 23 can no longer move (step S14). It should be noted that at this point, the interior of the system gripping sections 26, 27 is exposed to the ambient air AT, causing the system gripping sections 26, 27 to deform slightly into shapes along the contour of the section C1G of the first connecting piece C1 to which the system gripping sections 26, 27 abut. This is because the particles 3A, 3B filled into the pocket elements 2A, 2B flow easily.

[0054] Subsequently, a vacuum is drawn into the gripping sections 26, 27 (step S15). More precisely, the respective communication destinations of the pocket element communication lines 4A, 4B are switched by the switching mechanisms 7A, 7B, so that the pocket element communication lines 4A, 4B communicate with the vacuum source communication lines 5A, 5B, and the respective interiors of the pocket elements 2A, 2B are depressurized by the vacuum source LP. This brings the gripping sections 26, 27 into a hard and non-deformable state, while the shapes of the gripping sections 26, 27 generally follow the shape of the section C1G to be gripped in the first connecting piece C1, against which the gripping sections 26, 27 rest. Thus, the clamping mechanism 20S can grip the section C1G to be gripped in the first connecting piece C1 accordingly. It should be noted that the Fig. 3, Fig. 4 show a case in which the first connecting piece C1 is gripped in a state in which an axis C1X of the first connecting piece C1 lies along the axis 20X of the clamping mechanism 20S.

[0055] The clamping mechanism 20S is then moved by the robot hand body 31 to a predetermined position near the second connection C2 (one movement step S2).

[0056] In a subsequent insertion step S3, an insertion section C1S of the first connector C1 is inserted into the insertion hole C2H of the second connector C2 (a movement step S2). More precisely, the robot hand body 31 is moved so that the clamping mechanism 20S is moved along one direction (a feed direction PH) along the axis 20X, as indicated by a black arrow in Fig. 3 specified. At this point, while the axis 20X of the clamping mechanism 20S is held along a hole axis C2X of the second connector C2, the insertion section C1S of the first connector C1 is gradually brought close to the second connector C2 and inserted into the insertion hole C2H of the second connector C2 (a movement step S31, see Fig. 4) It should be noted that in embodiment 1 the feed direction PH, indicated by the black arrow in Fig. The line 3 shown runs along the Z-direction described above. Furthermore, the... Fig. 3, Fig. 4 a case in which the axis 20X of the clamping mechanism 20S lies along the axis C1X of the first connecting piece C1, so that the axis C1X also lies along the bore axis C2X.

[0057] When the first connector C1 is inserted, the force sensor 40 detects an external force HF exerted on the first connector C1. The process then returns to motion step S31 and the insertion of the first connector C1 continues if an external force (an external force in the feed direction) rfz in the feed direction PH (the Z-direction) detected by the force sensor 40 is less than a predetermined threshold for external forces in the feed direction THz (rfz < THz, Yes in step S33).

[0058] Meanwhile, if the external force rfz in the feed direction reaches a magnitude equal to or greater than the threshold value THz for the external force in the feed direction (rfz ≥ THz, No in step S33), it is assumed that the external force rfz in the feed direction has increased because the first connector C1 is being inserted into the blind end of the insertion hole C2H of the second connector C2. In light of this, the process proceeds to a release step S4. Here, the movement of the robot hand body 31 is stopped, and the gripping elements 22, 23 of the clamping mechanism 20S are moved to the release sides 20B, thus releasing the first connector C1 from the clamping mechanism 20S. This completes the insertion of the first connector C1 into the second connector C2.

[0059] At the time of inserting the first connecting piece C1 into the second connecting piece C2, it is preferable that, as in the Fig. 3, Fig. Figure 4 shows a state in which the axis C1X of the first connector C1, gripped by the clamping mechanism 20S, lies along the axis 20X of the clamping mechanism 20S, and the axis C1X of the first connector C1 lies along the hole axis C2X of the second connector C2. The clamping mechanism 20S is moved along the feed direction PH (the Z-direction) indicated by the black arrow, and the first connector C1 is inserted into the second connector C2. However, when the first connector C1 is gripped by the clamping mechanism 20S, it is not always possible to grip the first connector C1 in such a way that the axis C1X of the first connector C1 lies along the axis 20X of the clamping mechanism 20S, as shown in Figure 4. Fig. Figure 3 shows that in some cases the first connector C1 can be gripped in such a way that it deviates from a predetermined position, or it can be gripped in a state where the axis C1X is inclined. Furthermore, in some cases the second connector C2 can be positioned in such a way that it deviates from a predetermined position, or it can be brought into a state where the hole axis C2X is inclined.

[0060] In a case where the positions or the like of the first connecting piece C1 and the second connecting piece C2 are not suitable as such, even if the first connecting piece C1 is to be inserted into the second connecting piece C2 by the robot hand body 31 in insertion step S3 by adjusting the clamping mechanism 20S along a predetermined locus or in a predetermined position, the first connecting piece C1 may in some cases not be suitable for insertion into the blind end of the insertion hole C2H.In such cases, a condition often arises in which the insertion section C1S of the first connector C1 is partially placed inside the insertion hole C2H of the second connector C2H, but a distal end circumferential section C1SE of the insertion section C1S of the first connector C1 abuts an inner circumferential surface C2HI of the insertion hole C2H of the second connector C2, so that the first connector C1 is stuck in the insertion hole C2H of the second connector C2 (see . Fig. 6).

[0061] Furthermore, it is noted in this case that the force sensor 40 detects unusual external forces in directions (X-direction and Y-direction) perpendicular to the feed direction PH (Z-direction), as well as the external force (the external force rf in the feed direction) in the feed direction PH (Z-direction), since the external force rf is exerted on the first connecting piece C1, and so on. It should be noted that, for the sake of simplicity, in the present embodiment only one unusual external force rfx in the X-direction (sliding direction of the gripping elements 22, 23) is considered as unusual external forces in the directions (X-direction and Y-direction) perpendicular to the feed direction PH (Z-direction).

[0062] Furthermore, in the present embodiment, the pocket-shaped actuators 1A, 1B are used for the gripping sections 26, 27 of the gripping elements 22, 23. In this context, the inventors have conceived the following situation. That is, even if the first connecting piece C1 cannot be inserted sufficiently to the blind end of the insertion opening C2H of the second connecting piece C2 in the middle of the insertion step S3 as described above, the insertion of the first connecting piece C1 into the second connecting piece C2 can continue if the position of the first connecting piece C1 can be changed after gripping by the clamping mechanism 20S and the insertion into the insertion step S3 is resumed after the change in position.Furthermore, by repeating the change of position and restarting the insertion one or more times, the insertion of the first connecting piece C1 into the second connecting piece C2 can be finally completed.

[0063] In light of this, the present embodiment provides unusual external force monitoring in step S32 during the movement of the first connecting piece C1 in movement step S31. In the unusual external force monitoring step S32, it is checked whether the magnitude |rfx| of the unusual external force rfx detected by the force sensor 40 is less than an unusual external force threshold THx. If the magnitude |rfx| of the unusual external force rfx is less than the threshold THx (|rfx| < THx), the process continues in step S33 as described above. Meanwhile, if the unusual external force monitoring step S32 is negative, the process continues.In a case where the magnitude |rfx| of the unusual external force rfx is equal to or greater than the threshold THx of the unusual external force (|rfx| ≥ THx), the process continues with a motion stop step S34, and the movement of the first connector C1 in the feed direction PH is temporarily stopped. Then, in a position change step S35, the position of the first connector C1 is changed using the insertion gripping sections 26, 27 (the pocket-shaped actuators 1A, 1B). Next, in a re-gripping step S36, the first connector C1 is gripped again by the gripping elements 22, 23. Finally, in a restart step S37, the temporarily stopped motion step S31 is resumed, so that the insertion of the first connector C1 continues. This completes the insertion of the first connector C1 into the second connector C2.

[0064] It should be noted that the following section describes details of step S32 for monitoring unusual external forces, the motion stop step S34, the posture change step S35, the re-gripping step S36, and the restart step S37. In an insertion operation, in a case where the postures of the first connector C1 and the second connector C2 are appropriate, as described in the Fig. 3, Fig. As shown in Figure 4, i.e., in an insertion operation where the first connector C1 is gripped such that the axis 20X of the clamping mechanism 20S lies along the axis C1X of the first connector C1, and the clamping mechanism 20S is advanced in the feed direction PH (the Z-direction) such that the axes 20X, C1X lie along the hole axis C2X of the second connector C2, it is difficult to describe the operations from steps S32 to S37.

[0065] In view of this, by imitating a case in which a gripping position of the first connecting piece C1 by the clamping mechanism 20S is not suitable, or a case in which a placement position of the second connecting piece C2 is not suitable, such a case is separately defined in the insertion step S3, while a part of the insertion section C1S of the first connecting piece C1 is securely placed in the insertion hole C2H of the second connecting piece C2, the distal end circumferential section C1SE of the insertion section C1S of the first connecting piece C1 rests against the inner circumferential surface C2HI of the insertion hole C2H of the second connecting piece C2, so that the first connecting piece C1 is inserted into the insertion hole C2H of the second connecting piece C2.This means that the first connecting piece C1 is gripped such that the axis 20X of the clamping mechanism 20S lies along the axis C1X of the first connecting piece C1, and the first connecting piece C1 is intentionally inserted diagonally into the entry hole C2H of the second connecting piece C2. That is, the clamping mechanism 20S is moved in the feed direction PH (Z-direction) such that the axis 20X of the clamping mechanism 20S diagonally intersects the bore axis C2X of the second connecting piece C2 at an offset angle θ1 (see figure). Fig. 6) A method for changing the gripping position of the first connector C1 by the clamping mechanism 20S in the insertion step S3 and for inserting the first connector C1 into the second connector C2 in such a case is described below. It should be noted that in this case, too, the gripping step S1, the movement step S2, and the release step S4 are the same, which is why their description is omitted in the following description.

[0066] As described above, in gripping step S1 the first connecting piece C1 is gripped such that the axis 20X of the clamping mechanism 20S lies along the axis C1X of the first connecting piece C1, and then the clamping mechanism 20S is moved to a position near the second connecting piece C2 (the movement step S2, see Fig. 5) Subsequently, in movement step S31, the clamping mechanism 20S is advanced in the feed direction PH indicated by the black arrow during the insertion step S3. This places a part (a lower left corner in Fig. 6) of the distal end circumference C1SE of the first connector C1 on the inner circumferential surface C2HI of the insertion hole C2H of the second connector C2. This causes the first connector C1 to receive the external force rf as a reaction force from the inner circumferential surface C2HI of the insertion hole C2H, as shown in Fig. Figure 6 shows that the external force rf is also transmitted to the clamping mechanism 20S, the force sensor 40 and the robot hand body 31.

[0067] The external force rf is subdivided into the external force rfz in the feed direction PH (the Z-direction) and the unusual external force rfx (an unusual external force rfxb before stopping) in the sliding direction (the X-direction) of the gripping elements 22, 23, wherein the sliding direction (the X-direction) is perpendicular to the feed direction (the Z-direction), as shown in Fig. Figure 6 is shown. Then, in the monitoring step S32 of the unusual external force, it is determined whether the magnitude |rfx| of the unusual external force rfx is less than the threshold THx of the unusual external force (|rfx| < THx). If yes, i.e., if the unusual external force rfx is small, the process proceeds to the previously described step S33, and the subsequent processes are executed. Meanwhile, if no, i.e., if the magnitude |rfx| of the unusual external force is equal to or greater than the threshold THx (|rfx| <THx) der ungewöhnlichen äußeren Kraft ist, fährt der Prozess mit dem Bewegungsanhalteschritt S34 fort, und die Bewegung des ersten Verbindungsstücks C1 durch den Roboterhandkörper 31 in Vorschubrichtung PH wird vorübergehend angehalten.

[0068] Subsequently, in posture change step S35, the inner side of the attachment gripping section (the attachment gripping section 27 on the lower side) is formed from the attachment gripping sections 26, 27 (the pocket-shaped actuators 1A, 1B). Fig. 7) on one side where the unusual external force rfx is applied, it is released to the ambient air AT. That is, the switching mechanism 7B is switched by the switching control element 8 so that the interior of the pocket-shaped actuator 1B communicates with the ambient air AT (step S351). This brings the system gripping section 27 (the pocket-shaped actuator 1B) into a soft and slightly inelastic deformable state.

[0069] Meanwhile, the interior of the attachment gripping section (the attachment gripping section 26 on the upper side in Fig. 7) on a side opposite the side on which the unusual external force rfx is applied, connected to the overpressure source HP. That is, the switching mechanism 7A is switched by the switching control element 8 so that the interior of the pocket-shaped actuator 1A communicates with the overpressure source communication line in order to communicate with the overpressure reserve tank HT (step S352). This causes the plant gripping section 26 (the pocket-shaped actuator 1A) to inflate like a balloon and be brought into the elastically deformable state, and as in Fig. As shown in Figure 7, the first connecting piece C1 is pressed by a compressive force F, indicated by a black arrow. As a result, the first connecting piece C1 moves from a position indicated by a line with alternating long dashes and two short dashes to a position indicated by a solid line, and the clamping section 27 (the pocket-shaped actuator 1B) deforms. It should be noted that, due to the movement of the first connecting piece C1, its axis C1X does not lie along the axis 20X of the clamping mechanism 20S.

[0070] The process then proceeds to the next gripping step, S36. Here, the two gripping elements 22 and 23 are moved back to the gripping sides 20A (the inner sides), and the section C1G of the first connecting piece C1 to be gripped is clamped between the connecting sections 26 and 27 until the gripping elements 22 and 23 can no longer move (step S361). Furthermore, the switching mechanisms 7A and 7B are activated by the switching control element 8 so that the system gripping sections 26 and 27 (the pocket-shaped actuators 1A and 1B) communicate again with the vacuum source communication lines 5A and 5B, respectively, and thus communicate with a vacuum reserve tank LT (of the vacuum source LP) (step S362). In this way, the first connecting piece C1 is gripped again by the gripping elements 22 and 23 when its position changes.

[0071] Furthermore, in restart step S37, the temporarily paused movement step S31 is resumed and the insertion of the first connecting piece C1 continues (see Fig. 8) As described above, an external force rfa, an external force rfza in the feed direction, and an unusual external force rfxa can be eliminated after restarting (rfa = rfza = rfxa = 0), or the unusual external force rfxa can be reduced compared to the unusual external force rfxb before stopping (rfxa < rfxb) because the position of the first connector C1 is changed. Then, steps S31 to S33 are repeated as described above. After a negative determination (No) (rfz ≥ THz) in step S33, the movement of the robot hand body 31 is stopped, and the grippers 22, 23 are moved to the release sides 20B, so that the first connector C1 is released from the clamping mechanism 20S (release step S4). This completes the insertion of the first connector C1 into the second connector C2.It should be noted that if the result is again negative (No) (|rfx| ≥ THx) in step S32 during the repetition of steps S31 to S33, steps S34 to S37 will be repeated, so that the insertion will be restarted.

[0072] In general, if the offset angle θ1 is sufficiently small (e.g., if θ1 = 0 to 7.5 degrees), the distal end circumference C1SE of the first connector C1 does not contact the inner circumferential surface C2HI of the insertion hole C2H of the second connector C2. Therefore, the magnitude of the unusual external force rfxa after restarting is smaller than the threshold THx of the unusual external force (|rfxa| < THx). Even if the distal end circumference C1SE of the first connector C1 does contact the inner circumferential surface C2HI of the insertion hole C2H of the second connector C2, the magnitude of the unusual external force rfxa after restarting is smaller than the threshold THx of the unusual external force (|rfxa| < THx). Accordingly, the insertion of the first connecting piece C1 continues in step S31 without temporarily stopping the insertion in step S34.This completes the insertion of the first connecting piece C1 into the second connecting piece C2.

[0073] Meanwhile, in a case where the offset angle θ1 is large up to a certain degree (e.g. in a case of θ1 = 7.5 to 18 degrees), if the position of the first connecting piece C1 is changed one to three times (steps S34 to S37 are performed one to three times), the insertion of the first connecting piece C1 can be continued in step S31 so that the insertion of the first connecting piece C1 into the second connecting piece C2 can be completed.

[0074] It should be noted that in a case where the offset angle θ1 is too large (e.g. θ1 ≥ 18 degrees), even if the position of the first connector C1 is repeatedly changed in steps S34 to S37, the insertion of the first connector C1 into the second connector C2 may not be completed.

[0075] It is assumed that a range of the offset angle θ1 (e.g. θ1 = 7.5 to 18 degrees) that can achieve the completion of the insertion of the first connector C1 into the second connector C2 by repeatedly changing the position (steps S34 to S37) varies depending on the shapes of the first connector C1 and the insertion hole C2H of the second connector C2, the size of a gap between the first connector C1 and the insertion hole C2H, the materials of the connectors, etc.

[0076] Further, as in the Fig. 3, Fig. Figure 4 shows that in a case where the offset angle θ1 formed between the hole axis C2X of the second connector C2 and the axis 20X of the clamping mechanism 20S satisfies θ1 = 0, it is assumed that a permissible range of gripping position of the first connector C1 by the clamping mechanism 20S and a permissible range of placement position of the second connector C2 also depend on the shapes of the first connector C1 and the insertion hole C2H of the second connector C2, the size of the gap between the first connector C1 and the insertion hole C2H, the materials of the connector, etc.The permissible range of the gripping position of the first connector C1 by the clamping mechanism 20S and the permissible range of the placement position of the second connector C2 are ranges which can achieve the completion of the insertion of the first connector C1 into the second connector C2 by repeatedly changing the position (steps S34 to S37).

[0077] In any case, however, when using the robot hand 30, even if an unusual external force is exerted on the workpiece in the middle of the process due to an unsuitable gripping position of the first connector C1 (the workpiece) or similar, the first connector C1 can be inserted into the insertion hole C2H of the second connector C2 (the target workpiece) in a suitable manner by changing the gripping position of the first connector C1 (a position change step S35A). This reduces the likelihood that the first connector C1 cannot be inserted into the insertion hole C2H. Design 2

[0078] Next, embodiment 2 will be described with reference to Fig. 1 and the Fig. 9 to 15 are described. It should be noted that the following mainly describes a part that differs from embodiment 1, and a description of a similar part is omitted or simplified. Furthermore, a similar part has the same reference numeral. In a robot hand 130 according to embodiment 2, the robot hand body 31, the robot hand controller 32, and the force sensor 40 have the same configurations as in the robot hand 30 of embodiment 1 (see the Fig. 1, Fig. 2) Furthermore, in a clamping device 120 of embodiment 2, the clamping body section 21 of a clamping mechanism 120S and the clamping jaw elements 24, 25 of the gripping elements 122, 123 are also the same as the clamping body section 21 of the clamping mechanism 20S of the clamping device 20 and the clamping jaw elements 24, 25 of the gripping elements 22, 23 in embodiment 1. Furthermore, similar to embodiment 1, as indicated by arrows in Fig. 9 indicated, directions in which the gripping elements 122, 123 are close together are referred to as gripping sides 120A when a workpiece is gripped, and directions in which the gripping elements 122, 123 are spaced apart from each other are referred to as release sides 120B when the gripped workpiece is released.

[0079] It should be noted that in embodiment 1 the gripping elements 22, 23 each contain a contact gripping section 26, 27 as a pocket-shaped actuator 1A, 1B.

[0080] On the other hand, in the robot hand 130 of embodiment 2, the gripping elements 122, 123 of the clamping body section 121 each contain a contact gripping section 126, 127 and a base-end contact section 128, 129, as in Fig. 9 shown. That is, the gripping elements 122, 123 contain respective contact gripping sections 126, 127, which are configured such that they bear against a workpiece (e.g. the first connecting piece C1) and grip the workpiece in a gripping state, wherein the contact gripping sections 126, 127 are provided on the inner sides of the clamping jaw sections 24B, 25B of the clamping jaw elements 24, 25. In addition, the gripping elements 122, 123 each include base-end contact sections 128, 129, which are configured such that they abut the workpiece from the base end sides BE of the gripping elements 122, 123, wherein the base-end contact sections 128, 129 are provided on distal end sides TE of the base sections 24A, 25A, so that the base-end contact sections 128, 129 are arranged closer to the base end sides BE than the contact gripping sections 126, 127.

[0081] The gripping sections 126, 127 and the base-end sections 128, 129 are pocket-shaped actuators 11A to 11D in pocket-shaped actuator systems 10A to 10D. Similar to the pocket-shaped actuators 1A, 1B in embodiment 1, the pocket-shaped actuators 11A to 11D consist of the corresponding pocket elements 12A to 12D and the corresponding particles 13A to 13D. The pocket elements 12A to 12D are soft, easily deformable, and airtight. The particles 13A to 13D are free-flowing and filled into the pocket elements 12A to 12D. Also in embodiment 2, the pocket elements 12A to 12D are made of nitrile rubber and the particles 13A to 13D are made of aluminum oxide particles. Furthermore, the pocket-shaped actuators 11A to 11D are operated by an actuator control device 19, which is connected to the vacuum source LP and the pressure source HP.

[0082] More precisely, the interior of each pocket element 12A to 12D of the pocket-shaped actuators 11A to 11D is connected to the respective switching mechanisms 17A to 17D via the pocket element communication lines 14A to 14D. The switching mechanisms 17A to 17D are connected to the ambient air AT, to the negative pressure source LP via corresponding negative pressure source communication lines 15A to 15D, and to the positive pressure source HP via corresponding positive pressure source communication lines 16A to 16D. Based on control by a switching control element 18, the interior of the pocket elements 12A to 12D can be switched to the ambient air AT, the negative pressure source LP, or the positive pressure source HP via corresponding pocket element communication lines 14A to 14D. The switching control element 18 is connected to the clamping element control section 20C.The switching control element 18 performs drive controls for the robot hand body 131, the clamping body section 121 and the pocket-shaped actuators 11A to 11D through cooperation of the robot hand control unit 32, the clamping body control section 20C and the switching control element 8, so that the clamping body section 121 can grip a workpiece appropriately and perform a predetermined operation.

[0083] It should be noted that the pocket-shaped actuators 11A to 11D can be brought into three states, i.e., the "elastically deformable state", the "soft and slightly inelastically deformable state", and the "hard and non-deformable state", by switching the air pressures within the pocket elements 12A to 12D. This corresponds to the pocket-shaped actuators 1A, 1B in embodiment 1, and therefore their descriptions are omitted.

[0084] In the pocket-shaped actuator systems 10A to 10D in embodiment 2, the pocket-shaped actuators 11A to 11D can each be brought into three states, i.e. into the “elastically deformable state”, into the “soft and slightly inelastically deformable state” and into the “hard and non-deformable state”.

[0085] Furthermore, in the clamping device 120 in embodiment 2, the contact gripping sections 126, 127 and the base-end contact sections 128, 129 of the clamping mechanism 120S are formed by the pocket-shaped actuators 11A to 11D in the pocket-shaped actuator systems 10A to 10D, so that the contact gripping sections 126, 127 and the base-end contact sections 128, 129 can reach the three states mentioned above. For this reason, in the clamping device 120, the contact gripping sections 126, 127 can also be brought into contact with the first connecting piece C1 to be gripped by selecting one of the three states mentioned above, thereby making it possible to increase the degree of freedom of a gripping state of the first connecting piece C1 and to grip the first connecting piece C1 more appropriately.Furthermore, the base end-side plant sections 128, 129 are brought into any one of the three states, making it possible to further increase the degree of freedom of a gripping state of the first connecting piece C1 and to achieve a more suitable gripping of the first connecting piece C1.

[0086] Furthermore, the gripping sections 126, 127 and the base-end gripping sections 128, 129 are formed by the pocket-shaped actuators 11A to 11D and can select any of the three states mentioned above. This further increases the degree of freedom of the gripping state of the first connecting piece C1 by the gripping elements 122, 123 and achieves a more suitable gripping of the first connecting piece C1.

[0087] For this reason, the force sensor 40 can detect an unusual external force if, at the time the gripping elements 122, 123 grasp a workpiece (e.g., the first connecting piece C1) and perform a predetermined operation, the gripped workpiece, the gripping elements 122, 123, or the clamping body section 121 are in contact with other elements and an unusual external force is exerted on the gripped workpiece, the gripping elements 122, 123, or the clamping body section 121. Accordingly, if the force sensor 40 detects the unusual external force, a fault correction can be performed on the workpiece, so that, for example, the movement of the workpiece by the robot hand body 131 is stopped. Furthermore, the force sensor 40 is a six-axis force sensor, and therefore, if a predetermined process is carried out on a workpiece, the force sensor 40 can detect an external force acting on the workpiece or similar.The force exerted on the gripping mechanism can be identified more precisely by dissecting the external force onto the respective axes.

[0088] Next, a workpiece process using the robot hand 130 is described, with reference to a process of gripping the first connecting piece C1 as a workpiece by the clamping mechanism 120S of the robot hand 130 and inserting the first connecting piece C1 into the insertion hole C2H of the second connecting piece C2 of the object OJ as the insertion target workpiece, similar to embodiment 1 (see the Fig. 10 to 12). It should be noted that the object as the introduction target workpiece and the second connecting piece C2 thereof are arranged at a predetermined position.

[0089] First, in a gripping step S1A, the section C1G of the first connecting piece C1 to be gripped is grasped by the gripping elements 122, 123 of the clamping mechanism 120S. The gripping step S1A is generally similar to the gripping step S1 in embodiment 1 (steps S11 to S15, see Figure 1). Fig. 5) Gripping step S1A differs from gripping step S1 in that, instead of step S12, the respective inner surfaces of the system gripping sections 126, 127 and the base-end system sections 128, 129 (the pocket elements 12A to 12D) communicate with the ambient air AT (step S12A), and instead of step S15, vacuum pulling is carried out in the system gripping sections 126, 127 and the base-end system sections 128, 129 (the pocket elements 12A to 12D) (step S15A). This allows the clamping mechanism 120S to grip the section C1G of the first connecting piece C1 accordingly. It should be noted that, similar to the Fig. 3, Fig. 4 in embodiment 1, which Fig. 10, Fig. 11 show a case in which the first connecting piece C1 is gripped in a state in which the axis C1X of the first connecting piece C1 lies along an axis 120X of the clamping mechanism 120S.

[0090] Then, similar to embodiment 1, the clamping mechanism 120S is moved by the robot hand body 131 into a predetermined position near the second connecting piece C2 (the movement step S2).

[0091] In a subsequent insertion step S3A, the insertion section C1S of the first connector C1 is inserted into the insertion hole C2H of the second connector C2 in a process similar to embodiment 1. More precisely, the robot hand body 131 is moved such that the clamping mechanism 120S is moved in the feed direction PH along the axis 120X, as indicated by a black arrow in Fig. 10. At this point, while the axis 120X of the clamping mechanism 120S is held along the hole axis C2X of the second connector C2, the insertion section C1S of the first connector C1 is gradually brought close to the second connector C2 and inserted into the insertion hole C2H of the second connector C2 (the movement step S31, see Fig. 11). In embodiment 2, the feed direction PH is also along the Z-direction. Furthermore, the Fig. 10, Fig. 11 a case in which the axis 120X of the clamping mechanism 120S lies along the axis C1X of the first connecting piece C1, so that the axis C1X also lies along the bore axis C2X.

[0092] When the insertion section C1S of the first connector C1 is inserted into the insertion hole C2H of the second connector C2 (No in step S33), the process proceeds to release step S4, similar to embodiment 1. Here, the movement of the robot hand body 131 is stopped, and the first connector C1 is released from the clamping mechanism 120S. This completes the insertion of the first connector C1 into the second connector C2.

[0093] It should be noted that the insertion step S3A in embodiment 2 differs from the insertion step S3 in embodiment 1 by the posture change step S35A and a renewed gripping step S36A, while the other part of the insertion step S3A in embodiment 2 is similar to the insertion step S3 in embodiment 1. It is difficult to compare these steps in the Fig. 10, Fig. to describe the 11 states shown. Considering this, similar to the description using the Fig. In embodiment 2, by simulating a case in which the gripping position of the first connecting piece C1 by the clamping mechanism 120S is not suitable, or a case in which the placement position of the second connecting piece C2 is not suitable, the clamping mechanism 120S is moved in the feed direction PH (Z-direction) such that the axis 120X of the clamping mechanism 120S diagonally aligns with the hole axis C2X of the second connecting piece C2 at an offset angle θ2 (see Fig. 6) with regard to the Fig. 13 to 15 intersects. The following describes a process in which the gripping position of the first connector C1 is changed by the clamping mechanism 120S, and in such a case, the first connector C1 is inserted into the second connector C2 in the insertion step S3A. It should be noted that in this case, too, the gripping step S1A, the movement step S2, and the release step S4 are the same, which is why their description is omitted in the following description.

[0094] As described above, in gripping step S1A the first connector C1 is gripped such that the axis 120X of the clamping mechanism 120S lies along the axis C1X of the first connector C1, and then the clamping mechanism 120S is moved to a position near the second connector C2 (the movement step S2, see Fig. 12). Subsequently, in movement step S31, the clamping mechanism 120S is advanced in the feed direction PH during the insertion step S3A. This places a section (a lower left corner in Fig. 13) of the distal end circumferential section C1SE of the first connecting piece C1 to the inner circumferential surface C2HI of the insertion hole C2H of the second connecting piece C2. This results in the first connecting piece C1 receiving the external force rf as a reaction force from the inner circumferential surface C2HI of the insertion hole C2H as shown in Fig. Figure 13 shows that the external force rf is also transmitted to the clamping mechanism 120S, the force sensor 40 and the robot hand body 131.

[0095] Subsequently, in monitoring step S32 for unusual external force, similar to embodiment 1, it is determined whether the magnitude |rfx| of the unusual external force rfx (the unusual external force rfxb before stopping) is less than the threshold THx of the unusual external force (|rfx| < THx) or not. If the unusual external force rfx is small (Yes), the process continues with step S33 described above, and the subsequent processes are executed. Meanwhile, if the magnitude |rfx| of the unusual external force is equal to or greater than the threshold THx (|rfx| ≥ THx) (No), the process continues with the motion stop step, and the movement of the first connecting piece C1 by the robot hand body 131 in the feed direction PH is temporarily stopped.

[0096] In the subsequent posture change step S35A, unlike in embodiment 1, a calculation is performed on the basis of a direction, a magnitude or similar of the unusual external force rfx to determine which of a vacuum, the ambient air and the overpressure the respective interior of the system gripping sections 126, 127 and the base end system sections 128, 129 (the pocket-shaped actuators 11A to 11D) are to be connected to (step S353A).

[0097] Subsequently, the interior of the gripping section or the base-end gripping section (the gripping section 127 on the lower side in) described in step S353A is Fig. 14) released to the ambient air AT. That is, the switching mechanism 17B is switched by the switching control element 18 so that the interior of the pocket-shaped actuator 11B communicates with the ambient air AT (step S351A). This brings the system gripping section 127 (the pocket-shaped actuator 11B) into a soft and slightly inelastic deformable state.

[0098] Furthermore, the interior of the gripping section or the base-end gripping section (the gripping section 126 on the top and the base-end gripping section 129 on the bottom) is described in Fig. 14), which is designated in step S353A, is connected to the overpressure source HP. That is, the switching mechanisms 17A, 17D are switched by the switching control element 18 so that the interior of the pocket-shaped actuator 11A, 11D communicates with the overpressure source communication lines 16A, 16D and thus with the overpressure reserve tank HT (step S352A). The interior of the remaining plant gripping section or the remaining base-end plant section (the base-end plant section 128 on the top side in Fig. 14) remains connected to the vacuum source LP without switching the switching mechanism 17C, i.e., remains connected to the vacuum, so that the remaining attachment gripping section or the remaining base-end attachment section is held in a hard and non-deformable state. In this process, the attachment gripping section 126 and the base-end attachment section 129 (the pocket-shaped actuators 11A, 11D) are inflated like a balloon and brought into an elastically deformable state, and the first connecting piece C1 is pressed by pressure forces F1, F2 so that it rotates clockwise, as shown in Fig. Figure 14 shows that the first connecting piece C1 moves from a position indicated by a line with alternating long and two short lines to a position indicated by a continuous line, and the contact gripping section 127 (the pocket-shaped actuator 11B) deforms. It should be noted that even during the movement of the first connecting piece C1, the axis C1X of the first connecting piece C1 does not lie along the axis 120X of the clamping mechanism 120S.

[0099] Similar to embodiment 1, two gripping elements 122, 123 are again moved to the gripping sides 120A (the inner sides), and the section C1G of the first connecting piece C1 to be gripped is clamped between the system gripping sections 26, 27 until the gripping elements 22, 23 can no longer move (step S361). Furthermore, the switching mechanisms 17A, 17B, 17D are switched by the switching control element 18 so that the system gripping sections 126, 127 and the base-end system sections 128, 129 (the pocket-shaped actuators 11A to 11D) communicate with the vacuum source communication lines 15A to 15D or with the vacuum reserve tank LT (of the vacuum source LP) (step S362A). In this way, the first connecting piece C1 is gripped again by the gripping elements 122, 123 when the position changes.

[0100] Then, similar to embodiment 1, in restart step S37 the temporarily stopped movement step S31 is resumed and the insertion of the first connecting piece C1 is continued (see Fig. 15) Since the position of the first connecting piece C1 is changed as already mentioned, in embodiment 2 the external force rfa, the external force rfza in the feed direction and the unusual external force rfxa can also be eliminated after restarting (rfa = rfza = rfxa = 0) or the unusual external force rfxa can be reduced compared to the unusual external force rfxb before stopping (rfxa < rfxb) (it should be noted that Fig. (15 shows the case rfxa = 0). Then steps S31 to S33 are repeated. After a negative determination (No) (rfz ≥ THz) in step S33, the movement of the robot hand body 131 is stopped and the gripping elements 122, 123 are moved to the release sides 120B, so that the first connector C1 is released from the clamping mechanism 120S (release step S4). This completes the insertion of the first connector C1 into the second connector C2.

[0101] It should be noted that if the result is again negative (No) (|rfx| ≥ THx) in step S32 during the repetition of steps S31 to S33, steps S34 to S37 will be repeated, so that the insertion will be restarted.

[0102] In contrast to a case where the gripping elements 22, 23 are only provided with the contact gripping sections 26, 27, as in the robot hand 30 in embodiment 1, in a case where the gripping elements 122, 123 are provided with corresponding contact gripping sections 126, 127 and corresponding base-end contact sections 128, 129, as in the robot hand 130 in embodiment 2, the first connecting piece C1 (the workpiece) can be brought into a more suitable position. For this reason, a range of the offset angle θ2, which allows for the completion of the insertion of the first connecting piece C1 into the second connecting piece C2 by repeatedly changing the position (steps S34 to S37, see Figure 1), can be adjusted. Fig. 12) can be made wider than the range of the offset angle θ1 in embodiment 1 (e.g. θ2 = 7.5 to 28 degrees).

[0103] It should be noted that, similar to embodiment 1, it is assumed that this area also depends on the shapes of the first connecting piece C1 and the insertion hole C2H of the second connecting piece C2, the size of the gap between the first connecting piece C1 and the insertion hole C2H, the materials of the connecting pieces, etc.

[0104] Further, as in the Fig. 10, Fig. Figure 11 shows that in a case where the offset angle θ2 formed between the hole axis C2X of the second connector C2 and the axis 120X of the clamping mechanism 120S satisfies θ2 = 0, it is assumed that a permissible range of gripping position of the first connector C1 by the clamping mechanism 120S and a permissible range of placement position of the second connector C2 also depend on the shapes of the first connector C1 and the insertion hole C2H of the second connector C2, the size of the gap between the first connector C1 and the insertion hole C2H, the materials of the connectors, etc.The permissible range of the gripping position of the first connector C1 by the clamping mechanism 120S and the permissible range of the placement position of the second connector C2 are ranges which can achieve the completion of the insertion of the first connector C1 into the second connector C2 by repeatedly changing the position (steps S34 to S37, see . Fig. 12).

[0105] However, even if an unusual external force is exerted on the workpiece in the middle of the process due to an inappropriate gripping position of the first connector C1 (the workpiece) or similar, the first connector C1 can still be inserted into the insertion hole C2H of the second connector C2 (the target workpiece) in a suitable manner by changing the gripping position of the first connector C1 (position change step S35A). This reduces the likelihood that the first connector C1 cannot be inserted into the insertion hole C2H.

[0106] Furthermore, when using the robot hand 130 in embodiment 2, in the posture change step S35A, the pocket-shaped actuator 11C, which forms the base-end contact section 128, or the pocket-shaped actuator 11D, which forms the base-end contact section 129, is inflated so that the first connecting piece C1 (the workpiece) can be moved to the distal end faces TE of the gripping elements 122, 123 equipped with the pocket-shaped actuators 11C, 11D. This allows the posture of the first connecting piece C1 to be changed such that the magnitude |rfx| of the unusual external force after restart is smaller than the magnitude of the unusual external force before stopping.With such a configuration, the first connecting piece C1 can be inserted into the insertion hole C2H of the second connecting piece C2 (the insertion target workpiece) in a wider range, further reducing the case where the first connecting piece C1 cannot be inserted into the insertion hole C2H.

[0107] The above description describes the present invention based on embodiments 1 and 2. However, the present invention is not limited to embodiments 1 and 2 and can be modified and applied accordingly without departing from the core of the present invention.

[0108] Embodiments 1 and 2, for example, deal with an instance in which two clamping jaw-shaped gripping elements 22, 23, 122, 123 are provided in the clamping mechanism (the gripping device) 20S, 120S to grip a workpiece (e.g., the first connecting piece C1). However, three or more gripping elements can be provided in the gripping device to grip the workpiece.

[0109] Furthermore, the embodiments represent an example in which the contact gripping sections of a plurality of gripping elements (two in embodiments 1, 2) provided in the gripping device are all formed by the pocket-shaped actuators. However, a gripping device can be used in which none of the contact gripping sections of the gripping elements are formed by the pocket-shaped actuator.

Claims

[1] Gripping device, with a gripping mechanism comprising a plurality of gripping elements (122, 123), wherein the gripping mechanism is configured to grip a workpiece by moving at least one of the gripping elements (122, 123); and a variety of pocket-shaped actuator systems with: a pocket-shaped actuator (1A, 1B; 11A-11D) with an airtight pocket element (2A, 2B; 12A-12D) made of a flexible film material and flowable particles (3A, 3B; 13A-13D) filled into the pocket element (2A, 2B; 12A-12D); a pocket element communication line (4A, 4B; 14A-14D) configured to communicate with an interior of the pocket element (2A, 2B; 12A-12D) of the pocket-shaped actuator (1A, 1B; 11A-11D); a negative pressure source communication line (5A, 5B; 15A-15D) configured to communicate with a negative pressure source (LP) that has a lower air pressure than the ambient air; a pressure source communication line (6A, 6B; 16A-16D) configured to communicate with a pressure source (HP) that has a higher air pressure than the ambient air; a switching mechanism (7A, 7B; 17A-17D) configured to perform switching between communication destinations of the pocket element (2A, 2B; 12A-12D) of the pocket-shaped actuator (1A, 1B; 11A-11D), such that the interior of the pocket element (2A, 2B; 12A-12D) communicates with the ambient air, the negative pressure source communication line (5A, 5B; 15A-15D), and the positive pressure source communication line (6A, 6B; 16A-16D) via the pocket element communication line (4A, 4B; 14A-14D); and a switching control section (8, 18) configured to control the switching between the communication destinations by the switching mechanism (7A, 7B; 17A-17D); wherein the gripping elements (122, 123) comprise respective contact gripping sections (126, 127) which are configured to grip the workpiece by contacting the workpiece; wherein at least one of the gripping elements (122, 123) is configured such that the contact gripping section (126, 127) and a base-end contact section (128, 129) are formed by respective pocket-shaped actuators of the pocket-shaped actuator systems, wherein the base-end contact section (128, 129) is arranged closer to a base end of the at least one of the gripping elements (122, 123) than the contact gripping section (126, 127), wherein the base-end contact section (128, 129) is configured such that it rests against the workpiece from the base end of the at least one of the gripping elements (122, 123). [2] Gripping device according to claim 1, wherein the number of pocket-shaped actuator systems provided in the gripping device is twice as many or more than the number of gripping elements (122, 123); and The respective gripping sections (126, 127) and the respective base-end gripping sections (128, 129) of the gripping elements (122, 123) are formed by the respective pocket-shaped actuators of the pocket-shaped actuator systems. [3] Robot hand, with a robot hand body (131); the gripping mechanism of the gripping device according to claim 1 or 2, wherein the gripping mechanism is arranged in a distal end section of the robot hand body (131); and a force sensor (40) configured to detect an external force applied to the gripping elements (122, 123) of the gripping mechanism. [4] Robot hand according to claim 3, wherein the force sensor (40) is a six-axis force sensor arranged between the body (131) of the robot hand and the gripping mechanism. [5] Method for using the robot hand according to claim 3 or 4, comprising: a gripping step to grip the workpiece by the contact gripping sections (126, 127) of the gripping elements (122, 123) of the gripping mechanism; an insertion step for inserting the gripped workpiece into an insertion hole of an insertion target workpiece; and a release step to release the workpiece inserted into the insertion hole from being gripped by the gripping elements (122, 123), wherein the insertion step comprises: a movement step to move the gripping mechanism, which grips the workpiece, in the direction of the insertion hole of the insertion target workpiece along a hole axis of the insertion hole, while an external force exerted on the gripping mechanism via the workpiece is detected by the force sensor (40), a monitoring step for monitoring an unusual external force, wherein in the motion step it is monitored whether an unusual external force becomes greater than a predetermined unusual external force threshold, wherein the unusual external force lies along a direction that differs from a direction of an external force in the feed direction, wherein the external force in the feed direction lies along a direction that is opposite to a feed direction of the gripping mechanism, A motion-stopping step for temporarily halting a movement within a movement step when the unusual external force becomes greater than the unusual external force threshold. a posture change step for changing the posture of the workpiece, such that, after the motion has been stopped in the motion stop step, the pocket element (12A-12D) of at least one of the pocket-shaped actuators forming the contact gripping sections (126, 127) or the base-end contact sections (128, 129) bearing against the workpiece is inflated by causing the interior of the pocket element (12A-12D) to communicate with the overpressure source communication line (16A-16D) via the pocket element communication line (14A-14D), so that when the motion is restarted in the feed direction, the magnitude of an unusual external force exerted on the gripping elements via the workpiece after the restart is smaller than the magnitude of the unusual external force before the stop. a renewed gripping step to grip the workpiece again by the gripping elements (122, 123), and a restart step in which the movement in the feed direction is resumed, with the movement being temporarily stopped. [6] Method for use according to claim 5, wherein in the position change step at least one of the pocket elements (12C, 12D) forming the base end contact sections (128, 129) is inflated so that the workpiece is moved towards the distal end sides of the gripping elements (122, 123) which are provided with the base end contact sections (128, 129).

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