JP2013086186A - Holding device and robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding device and a robot capable of surely holding an object in a stable state.SOLUTION: The holding device 1 includes a pair of claws 10a, 10b which are brought into contact with the object 50 in at least three portions, and a pair of fingers 30a, 30b which support each of the pair of claws 10a, 10b and impart a holding force to the object 50 via the claws 10a and 10b. The holding device 1 intermittently imparts the holding force before holding the object 50.

Description

  The present invention relates to a gripping device and a robot.

  2. Description of the Related Art A gripping device that grips a columnar object or the like with a pair of claws is known (see, for example, Patent Document 1). In the gripping device (robot hand) described in Patent Document 1, the claw portion has a V-shaped valley-shaped cross section, and the object is on the inclined surface of the valley-shaped portion to which the sheet-like elastic body is fixed. Grasping the object in contact with

JP-A-5-253880

  However, in the gripping device of Patent Document 1 described above, when the object is gripped, for example, if the position of the object with respect to the nail portion is shifted, the force is evenly applied to each inclined surface of the V-shaped valley portion. Since it is not added, the elastic body deforms locally at the part in contact with the object, and the object cannot be gripped in a stable state, and the object cannot be gripped or dropped while carrying the object. There was a problem that there was a case. Further, since the object cannot be gripped in a stable state, there is a problem that if the gripping force is increased, the elastic body may be deteriorated or damaged, and the object may be deformed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A gripping device according to this application example supports a pair of claw portions that are in contact with an object at at least three locations, and each of the pair of claw portions, and is attached to the object via the claw portions. A pair of fingers for applying a gripping force, wherein the gripping force is intermittently applied before gripping the object.

  According to this configuration, the gripping device intermittently applies a gripping force to the object before gripping the object. That is, the application and release of the gripping force with respect to the object is repeated a plurality of times. For this reason, when the position where the object comes into contact with the nail when the gripping force is first applied is deviated from the appropriate position, the object is released from the nail by once releasing the gripping force. When the gripping force is applied again, the position where the object comes into contact with the claw portion can be brought close to the appropriate position. As a result, the object can be gripped in a stable state by bringing the position where the object contacts the claw portion close to an appropriate position, and thus it is possible to prevent the object from being missed or dropped while being transported. Can do.

  Application Example 2 In the gripping device according to the application example described above, it is preferable that an elastic body is provided at a position where the claw portion is in contact with the object.

  According to this configuration, the elastic body is provided at a position in contact with the object of the claw portion. For this reason, since a frictional force is provided between the object and the elastic body, the object can be gripped more reliably. In addition, since the elastic body is elastically deformed according to the gripping force, it is possible to prevent deformation and breakage of the object. Even when the elastic body is locally deformed at the position where the object is in contact with the claw portion, the application and release of the gripping force are repeated a plurality of times, so that the local deformation of the elastic body is returned to the original state. be able to.

  Application Example 3 In the gripping device according to the application example, it is preferable that the elastic body is a pressure sensor.

  According to this configuration, the pressure sensor is provided at a position in contact with the object of the claw portion. For this reason, it is possible to detect whether or not the object is held at an appropriate position based on the pressure detected by the pressure sensor at each position where the object contacts the claw portion. Thereby, it is possible to grasp the object in a more stable state by confirming that the object is in contact with the claw portion at an appropriate position and grasping the object.

  Application Example 4 In the gripping device according to the application example described above, it is preferable that a plurality of the pressure sensors are provided for each position in contact with the object.

  According to this configuration, the plurality of pressure sensors are provided for each position where the nail portion contacts the object. For this reason, it is possible to detect the pressure distribution and the direction in which the force component acts around each position where the object is in contact with the claw portion. As a result, the object can be gripped in a more stable state closer to the appropriate position.

  Application Example 5 It is preferable that the gripping device according to the application example further includes an elastic body that covers the pressure sensor.

  According to this configuration, since the elastic body covers the pressure sensor, the pressure sensor can be protected from dirt and damage.

  Application Example 6 In the gripping device according to the application example described above, it is preferable to include a vibrating unit that vibrates the claw when the gripping force is applied intermittently.

  According to this configuration, since the claw portion is vibrated when the gripping force is intermittently applied, the object can be more easily moved closer to the proper position and gripped. As a result, the object can be moved to an appropriate position in a shorter time, and deterioration and damage of the elastic body and the pressure sensor can be suppressed.

  Application Example 7 In the gripping device according to the application example described above, it is preferable that the vibrating portion includes a vibrating body as the vibrating portion.

  According to this configuration, since the vibrating body is provided in the claw portion, the claw portion can be vibrated with a simple configuration and a small output. Moreover, the load applied to portions other than the claw portion due to vibration can be reduced.

  Application Example 8 A robot according to this application example includes the gripping device described above.

  According to this configuration, since the above-described gripping device is provided, it is possible to provide a robot that can grip and reliably carry an object in a stable state.

The figure which shows schematic structure of the holding | gripping apparatus which concerns on 1st Embodiment. The figure explaining the holding | grip method of the holding | gripping apparatus which concerns on 1st Embodiment. The figure explaining the holding | grip method of the holding | gripping apparatus which concerns on 1st Embodiment. The figure which shows schematic structure of the holding | gripping apparatus which concerns on 2nd Embodiment. The figure which shows schematic structure of the holding | gripping apparatus which concerns on 3rd Embodiment. The schematic diagram which shows schematic structure of an example of the robot which concerns on 4th Embodiment. The figure which shows the structure of the holding | grip apparatus of a modification.

  Hereinafter, a gripping device and a robot according to an embodiment of the present invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced in size so that the part to be described can be recognized, and there are cases in which the ratios, angles, etc. of the dimensions of each component are different.

(First embodiment)
<Gripping device>
First, the gripping device according to the first embodiment will be described. FIG. 1 is a diagram illustrating a schematic configuration of a gripping device according to the first embodiment. Specifically, FIG. 1A is a perspective view of the gripping device, FIG. 1B is a view of the gripping device as viewed from above, and FIGS. 1C and 1D are pressure sensors included in the gripping device. FIG.

  The gripping device 1 according to the present embodiment is a device that grips an object having a columnar shape or the like. For example, the gripping device 1 is attached to a robot or the like to grip an object and carry it from a feeding place to a predetermined place. It is used.

  As shown in FIGS. 1A and 1B, the gripping device 1 includes a base 40, a pair of finger portions 30a and 30b attached to the base portion 40, and a pair connected to the pair of finger portions 30a and 30b. Claw portions 10a and 10b. Further, the claw portions 10a and 10b are provided with an elastic body 12 and a pressure sensor 20. The object 50 has, for example, a substantially cylindrical shape.

  In the state where the gripping device 1 is installed, for example, the finger portions 30a and 30b are assumed to extend along the horizontal direction, and the extending direction of the finger portions 30a and 30b is assumed to be the X direction. Moreover, the target object 50 gripped by the gripping device 1 is assumed to extend along the vertical direction, and the extension direction of the target object 50 is defined as the Z direction. Gravity Mg acts from the top to the bottom in the Z direction. A direction orthogonal to the X direction and the Z direction is taken as a Y direction. Below, it demonstrates with reference to this XYZ rectangular coordinate system.

  The finger portions 30a and 30b are made of, for example, a plate-like member made of metal, and are disposed to face each other in the Y direction. The finger portions 30a and 30b are attached to the base portion 40 so as to be movable along the Y direction. The claw portion 10a is connected to the opposite side of the finger portion 30a to the base portion 40, and the claw portion 10b is connected to the opposite side of the finger portion 30b to the base portion 40. As the finger portions 30a and 30b move in the Y direction, the interval between the finger portions 30a and 30b in the Y direction changes. By narrowing the interval between the finger portions 30a and 30b, the object 50 is sandwiched between the nail portions 10a and 10b, and a gripping force along the Y direction is applied to the object 50 from the nail portions 10a and 10b. The

  The claw portions 10a and 10b are made of, for example, a plate-like member made of a metal and have a V-shape when viewed from the Z direction. Each of the claw portions 10a and 10b has two surfaces 11 having different inclination angles with respect to the surfaces constituted by the X direction and the Z direction on the sides facing each other. The two surfaces 11 of the claw portion 10a are referred to as a surface 11a and a surface 11b in order from the finger portion 30a side, and the two surfaces 11 of the claw portion 10b are referred to as a surface 11c and a surface 11d in order from the finger portion 30b side. However, when these surfaces are collectively referred to, the surface 11 is simply referred to.

  The claw portions 10a and 10b are arranged so that the surface 11a and the surface 11b and the surface 11c and the surface 11d face each other. In the claw portions 10a and 10b, the boundary between the surface 11a and the surface 11b is a V-shaped valley 15a, and the boundary between the surface 11c and the surface 11d is a V-shaped valley 15b. The distance between the claw portions 10a and 10b in the Y direction is the largest at the positions of the valley portions 15a and 15b. The gripping device 1 holds the object 50 with the object 50 sandwiched between the surface 11a and the surface 11b side of the claw portion 10a and the surface 11c and the surface 11d side of the claw portion 10b.

  An elastic body 12 and a pressure sensor 20 are provided on each surface 11 of the claw portions 10a and 10b. The elastic bodies 12 and the pressure sensors 20 are respectively associated with the surfaces 11a, 11b, 11c and 11d on which the elastic bodies 12 and the pressure sensors 20 are arranged, and the elastic bodies 12a, 12b, 12c and 12d and the pressure sensors 20a, 20b, 20c and 20d To do. However, when these are generically referred to, they are simply referred to as the elastic body 12 and the pressure sensor 20.

  The elastic body 12 is a part in contact with the object 50, and prevents the object 50 from being damaged such as scratches and more reliably holds the object 50. The elastic body 12 is, for example, a sheet having a thickness of about 0.1 mm to 1 mm, and is provided on each surface 11 so as to cover the pressure sensor 20. The surface of the elastic body 12 is substantially parallel to each surface 11 of the claw portions 10a and 10b.

  The elastic body 12 is made of a material having a friction coefficient larger than that of the claw portions 10a and 10b and causing elastic deformation by an external pressure, for example, a silicone resin. Thereby, a contact area with the target object 50 can be enlarged, and a relative positional shift with the target object 50 can be suppressed. In addition, by covering the pressure sensor 20 with the elastic body 12, the pressure sensor 20 can be protected from dirt and damage.

  The pressure sensor 20 is provided to detect a position in contact with the object 50 in the claw portions 10a and 10b. As shown in FIGS. 1C and 1D, the pressure sensor 20 includes a substrate 21, a first electrode 22, an intermediate layer 23, and a second electrode 24 that are sequentially formed on the substrate 21. . 1C is a plan view viewed from the normal direction of the surface of the pressure sensor 20 (second electrode 24), and FIG. 1D is a cross-sectional view of the pressure sensor 20. FIG.

  The pressure sensor 20 is a sensor having an elastic pressure-sensitive material. For example, a general-purpose pressure sensor sheet having a substrate 21 made of a flexible resin material can be used. For example, a total of 16 first electrodes 22 are arranged in 4 rows and 4 columns. The surface of each pressure sensor 20 (second electrode 24) is substantially parallel to each surface 11 of the claw portions 10a and 10b on which the pressure sensors 20 (second electrodes 24) are arranged. The intermediate layer 23 is made of, for example, a pressure-sensitive conductive rubber such as a pressure-sensitive conductive elastomer.

  When a pressure in the thickness direction, that is, an external pressure from the normal direction is applied to the surface of the pressure sensor 20 (second electrode 24), the pressure sensor 20 is compared with a case where there is no external pressure, compared with the first electrode 22. Since the distance between the first electrode 24 and the second electrode 24 becomes smaller, the resistance value becomes smaller. The pressure sensor 20 detects a force acting on the object 50 by the gripping force of the gripping device 1 as an external pressure based on such a change in resistance value.

  If the pressure sensor 20 is a sensor having an elastic pressure-sensitive material, the pressure sensor 20 is a capacitance type pressure sensor that uses a dielectric material for the intermediate layer 23 to detect an external pressure by a change in capacitance value. Also good. In addition, the material, size, thickness, and the like of each component of the gripping device 1 are appropriately set according to the size, weight, shape, material, and the like of the object 50.

  FIG. 1B shows a position where the gripping device 1 grips the object 50 in the most stable state. Hereinafter, this position is referred to as a stable gripping position as an appropriate position. When the cross section in the X direction and the Y direction of the object 50 is circular, the center of the cross section (circular shape) of the object 50 connects the valleys 15a and 15b of the claw portions 10a and 10b when viewed from the Z direction. A position that substantially coincides with the center of the line parallel to the direction is the stable gripping position.

  In the stable gripping position, the object 50 is in contact with the four portions of the elastic bodies 12a, 12b, 12c, and 12d, and the gripping force by the claw portions 10a and 10b is substantially uniform from each of the elastic bodies 12a, 12b, 12c, and 12d. Has been granted. Therefore, at the stable gripping position, the pressure sensors 20a, 20b, 20c, and 20d detect pressures having substantially the same value. If the object 50 is gripped at a position deviating from the stable gripping position, there is a high possibility that the object 50 will be missed or the object 50 will fall while being carried.

  Next, a gripping method of the gripping device according to the first embodiment will be described with reference to FIGS. 2 and 3 are diagrams for explaining a gripping method of the gripping device according to the first embodiment. In addition, in FIG. 3, illustration of the finger part 30a and the nail | claw part 10a is abbreviate | omitted among a pair of finger part 30a, 30b and a pair of nail | claw part 10a, 10b.

  FIG. 2A shows a state before the object 50 is grasped by the grasping device 1. As shown in FIG. 2 (a), when gripping the object 50 with the gripping device 1, the target object 50 is not necessarily in the stable gripping position indicated by the two-dot chain line with respect to the gripping device 1, but rather is a solid line. In many cases, the position is out of the stable gripping position. FIG. 2A shows an example in which the object 50 is deviated from the stable gripping position to the −X side.

  FIG. 2B shows a state where the object 50 is gripped by the gripping device 1 from the state of FIG. When a gripping force is applied from the state of FIG. 2A, the object 50 comes off to the −X side from the stable gripping position, so that the object 50 is in contact with the elastic body 12 b and the elastic body 12 d. It does not contact the body 12a and the elastic body 12c.

  At this time, since the surface 11b and the surface 11d on which the elastic body 12b and the elastic body 12d are provided are inclined surfaces, the force of the Y direction component and the force of the X direction component act on the object 50 as the gripping force. To do. Therefore, as the gripping force is applied, a force for moving the object 50 in the + X direction acts as shown by a black thick arrow in FIG.

  However, when the object 50 tries to move from the state shown in FIG. 2 (a), the elastic body 12b and the elastic body 12d are elastically deformed so as to be extended in the + X direction at the A portion and in the + X direction at the B portion. Is compressed. As the elastic body 12b and the elastic body 12d are locally deformed in this way, the contact area between the elastic body 12b and the elastic body 12d and the object 50 is increased, and the frictional force is increased. As a result, the object 50 stops moving at a position slightly moved from the state of FIG. 2A and cannot move to the stable gripping position.

  If the object 50 is gripped and lifted by the gripping device 1 in this state, the object 50 may be missed or may be dropped while the object 50 is being carried. possible. Further, if an attempt is made to increase the gripping force for the purpose of preventing dropping or the like, the elastic body 12 is deteriorated or broken, the object 50 is deformed, and the output of the gripping device 1 must be increased. Become. Therefore, when gripping the object 50 with the gripping device 1, it is desirable to grip the object 50 at the stable gripping position.

  Therefore, the gripping device 1 according to the present embodiment is characterized in that a gripping force is intermittently applied before gripping the object 50 (before gripping and performing the next operation). That is, the gripping device 1 repeats the application and release of the gripping force to the object 50 a plurality of times before gripping the object 50.

  More specifically, in the gripping device 1, after the gripping force is once applied from the state of FIG. 2 (a) to the state of FIG. 2 (b), the gripping force is applied as shown in FIG. 3 (a). To release. Thereby, the nail | claw part 10b (elastic body 12d) and the claw part 10a (elastic body 12b) which are not illustrated leave | separate from the target object 50, and the target object 50 is open | released. Further, the elastic body 12b and the elastic body 12d return from the elastically deformed state to the original state.

  Subsequently, as shown in FIG. 3B, a gripping force is again applied to the object 50. Thereby, as shown by the thick black arrow, the force which moves the target object 50 to + X direction acts. The elastic body 12b and the elastic body 12d are elastically deformed, but the degree of deformation is smaller than that in the state of FIG. The object 50 moves from the state shown in FIG.

  Subsequently, as shown in FIG. 3C, the gripping force is released again. As a result, the object 50 is opened again, and the elastic body 12b and the elastic body 12d return from the elastically deformed state to the original state. And as shown in FIG.3 (d), by giving a gripping force with respect to the target object 50 further, the target object 50 moves to the stable gripping position side from the state of FIG.3 (c).

  In this way, by repeatedly applying and releasing the gripping force, the object 50 approaches the stable gripping position shown in FIG. 1B and comes into contact with the four locations of the elastic bodies 12a, 12b, 12c, and 12d. Become. At this time, based on the pressure values detected by the pressure sensors 20a, 20b, 20c, and 20d, whether or not the object 50 is in the stable gripping position, or how close the object 50 is to the stable gripping position. Can be detected. After the object 50 moves to the stable gripping position (or its allowable range), the gripping device 1 performs the following operations such as gripping the object 50 and lifting it up.

  For example, the intermittent application of the gripping force may be performed for a predetermined time (number of times) set in advance so that the object 50 moves to the stable gripping position (or its allowable range). Then, after intermittently applying the gripping force for a predetermined time (number of times), the pressure values (or mutual differences) detected by the pressure sensors 20a, 20b, 20c, and 20d are within a predetermined range. If not, the gripping force may be intermittently applied again. Further, intermittent application of the gripping force may be performed until the pressure values (or mutual differences) detected by the pressure sensors 20a, 20b, 20c, and 20d are within a predetermined range.

  Note that operations of the gripping device 1 such as intermittent application of gripping force, detection of pressure by the pressure sensor 20, and processing according to the detected pressure value are performed based on control of a control unit (not shown). When the gripping device 1 is attached to the robot, the control unit may be provided in the robot.

  Here, when the object 50 is a member having a protruding portion or a stepped portion such as a gear, the protruding portion or the like bites into the elastic body 12 and locally deforms, and the gripping force is reduced to 1 as usual. It is not easy to grip at a stable gripping position with a gripping method that applies only once. In the gripping device 1 of the present embodiment, by repeatedly applying and releasing the gripping force a plurality of times, even if the elastic body 12 is locally deformed, it can be restored to its original shape. Even with such a member, the object 50 can be easily held close to the stable holding position.

  As described above, according to the configuration of the gripping device 1 according to the first embodiment, the object 50 is moved to the claw portions 10a and 10b (elastic body) by repeatedly applying and releasing the gripping force to the object 50 a plurality of times. 12) can be brought close to the stable gripping position. Thereby, since the target object 50 can be gripped in a stable state, it is possible to prevent the target object 50 from being missed and to prevent the target object 50 from falling and to perform a reliable gripping operation.

  Further, according to the configuration of the gripping device 1 according to the first embodiment, since the gripping force can be stably held without excessively increasing the gripping force on the object 50, the elastic body 12 is deteriorated or damaged, and the target The deformation of the object 50 can be suppressed.

(Second Embodiment)
<Gripping device>
Next, a gripping device according to a second embodiment will be described. The gripping device according to the second embodiment is different from the first embodiment in that a plurality of pressure sensors are provided on each surface of the claw portion, but the other configurations are substantially the same. Constituent elements common to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 4 is a diagram illustrating a schematic configuration of a gripping device according to the second embodiment. Specifically, FIG. 4A is a view of the gripping device from above, and FIG. 4B is a side view of the gripping device.

  As shown to Fig.4 (a), the holding | grip apparatus 2 which concerns on 2nd Embodiment is provided with the base 40, a pair of finger part 30a, 30b, and a pair of nail | claw part 10a, 10b, and the nail | claw part 10a. , 10b, 16 pressure sensors 60 are provided on each of the surfaces 11 (11a, 11b, 11c, 11d). As shown in FIG. 4B, the sixteen pressure sensors 60 are arranged in a matrix in four rows and four columns in two directions parallel to each surface 11 and perpendicular to each other, for example, in the vertical direction (Z direction) and the horizontal direction. Has been placed.

  The pressure sensor 60 according to the second embodiment has the same configuration as the pressure sensor 20 of the first embodiment, but in addition to detecting a force from the normal direction of the surface of the pressure sensor 60. Thus, it is possible to detect a force in the direction of sliding parallel to the surface of the pressure sensor 60 (slip force component) and rotational torque.

  Since the gripping device 2 includes 16 pressure sensors 60 on each surface 11 of the claw portions 10a and 10b, the gripping device 2 has 16 different positions in the vertical and horizontal directions of each surface 11 respectively. The force (pressure) acting on the object 50 can be detected by the gripping force. Therefore, since the gripping device 2 can detect the pressure distribution at 16 locations in each surface 11, the object 50 has the claws 10a and 10b (elastic body 12) compared to the gripping device 1 of the first embodiment. It is possible to detect in more detail the position in contact with.

  Therefore, for example, the pressure detected by each pressure sensor 60 of the claw portions 10a and 10b when the object 50 is gripped at the stable gripping position on the basis of the position of the center of gravity of the object 50 in a state where no external force is applied. The distribution is stored in advance. Then, by comparing the pressure distribution detected by each pressure sensor 60 when a gripping force is applied to the object 50 with the pressure distribution stored in advance, it is detected how close the current gripping position is to the stable gripping position. be able to. Thereby, even when the gravity center position of the target object 50 is biased, the target object 50 can be gripped in a stable state.

  Incidentally, when the object 50 is gripped, even if the position where the object 50 is in contact with the claws 10a and 10b is the stable gripping position, the sliding force due to an external force such as gravity Mg is applied to the object 50, for example. When the rotational torque is applied, the object 50 may move away from the stable gripping position. If it does so, there exists a possibility that the target object 50 may be missed or the target object 50 may be dropped.

  On the other hand, since the gripping device 2 can detect a sliding force and a rotational torque parallel to the surface of the pressure sensor 60, when gripping the target object 50, the target object 50 can be detected from a stable gripping position. It is possible to detect that a moving force is working. Accordingly, in the gripping device 2, for example, when the target object 50 is about to fall, a gripping force for gripping the target object 50 is increased, or the posture of the target object 50 is changed and gripped again. And the object 50 can be gripped in a more stable state.

  Thus, according to the structure of the holding | gripping apparatus 2 which concerns on 2nd Embodiment, the 16 pressure sensors 60 are provided in each surface 11 of claw part 10a, 10b, and the pressure in 16 places in each surface 11 is provided. Therefore, the object 50 can be set in more detail as compared with the gripping device 1 of the first embodiment, and the object 50 can be set even when the center of gravity of the object 50 is biased. Whether or not 50 is in the stable gripping position can be detected more accurately.

  Moreover, according to the structure of the holding | gripping apparatus 2 which concerns on 2nd Embodiment, the sliding force and rotational torque parallel to the surface of the pressure sensor 60 are detected, and it moves to the direction which remove | deviates from the stable holding position with respect to the target object 50. Since it is possible to detect that a force is applied, the object 50 can be gripped in a more stable state. As a result, in the gripping device 2 according to the second embodiment, it is possible to more effectively prevent the object 50 from being missed and to drop the object 50 more effectively, thereby reliably gripping. .

(Third embodiment)
<Gripping device>
Next, a gripping device according to a third embodiment will be described. The gripping device according to the third embodiment is different from the above embodiment in that the gripping device includes a vibrating unit that vibrates the claw when intermittently applying the gripping force. The configuration is almost the same. Constituent elements common to the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 5 is a diagram illustrating a schematic configuration of a gripping device according to the third embodiment. FIG. 5A is a diagram illustrating an example of a gripping device including a vibrating portion at a base portion, and FIG. 5B is a diagram illustrating an example of a gripping device including a vibrating portion at a claw portion.

  The gripping device 3 according to the third embodiment shown in FIG. 5A includes a base 40, a pair of finger portions 30a and 30b, and a pair of claw portions 10a and 10b. It has. In the gripping device 3, the gripping force is intermittently applied before gripping the object 50 as in the gripping devices 1 and 2 of the above embodiment, but the vibration unit 70 grips the gripping force when the gripping force is intermittently applied. The entire apparatus 3 is vibrated at a predetermined frequency. Thereby, the nail | claw parts 10a and 10b which hold | grip the target object 50 vibrate. In addition, when attaching the holding | gripping apparatus 3 to a robot, it is good also as a structure provided with a vibration part in the robot side.

  In the gripping device 3, when the gripping force is intermittently applied to the object 50, vibration is applied to the claw portions 10 a and 10 b, so that the gripping force with respect to the object 50 is changed and elastic according to the vibration. The contact state between the body 12 and the object 50 changes. Therefore, compared with the case where vibration is not added to the claw portions 10a and 10b, the object 50 is easily moved from the position deviated from the stable gripping position to the stable gripping position.

  Thereby, the local deformation | transformation of the elastic body 12 can be decreased and the movement to the stable holding position of the target object 50 can be performed in a short time. In addition, since local deformation of the elastic body 12 and local deformation of the pressure sensors 20 and 60 associated therewith can be reduced, deterioration and damage of the elastic body 12 and the pressure sensors 20 and 60 can be suppressed.

  The frequency of vibration by the vibration unit 70 is, for example, about 0.1 Hz to 100 Hz. The frequency may be constant anywhere within this range, or may vary within this range. When vibration with a frequency higher than this is added, the elastic body 12 absorbs vibration and the effect is reduced. The direction of vibration by the vibration unit 70 is, for example, the Y direction. Note that the amplitude of vibration by the vibration unit 70 is appropriately set according to the thickness, elastic modulus, and the like of the elastic body 12.

  The gripping device 4 according to the third embodiment shown in FIG. 5B includes a base 40, a pair of finger portions 30a and 30b, and a pair of nail portions 10a and 10b. Respectively, the vibration parts 70a and 70b are provided. As the vibration units 70a and 70b, for example, a vibrator motor used in a mobile phone or a vibrator made of piezoelectric ceramics or the like can be used. The frequency of vibration by the vibration units 70a and 70b is, for example, about 0.1 Hz to 100 Hz.

  In the gripping device 4, the same effects as those of the gripping device 3 described above can be obtained with a simple configuration. Further, in the gripping device 4, the claw portions 10a and 10b that grip the object 50 are directly vibrated by the vibration portions 70a and 70b, so that the claw portions 10a and 10b are vibrated with a smaller output than the gripping device 3 described above. In addition, the load applied to portions other than the claw portions 10a and 10b due to vibration can be reduced. In addition, when the gripping device 4 is attached to the robot, the load on the robot side due to vibration can be suppressed as compared with the configuration in which the robot side includes a vibration unit, so that it is possible to reduce the output of the robot and to suppress deterioration in reliability. it can.

  Thus, according to the configuration of the gripping devices 3 and 4 according to the third embodiment, when the gripping force is intermittently applied to the object 50 by the vibrating portions 70, 70a, and 70b, the claw portions 10a and 10b. Therefore, the object 50 can be moved to the stable gripping position in a shorter time, and deterioration and damage of the elastic body 12 and the pressure sensors 20 and 60 can be suppressed.

  In addition, when a gripping force is intermittently applied to the object 50 without first adding vibration and the object 50 does not move to the stable gripping position, vibrations by the vibration units 70, 70 a, and 70 b are applied. In addition, a configuration may be adopted in which a gripping force is intermittently applied to the object 50 again.

(Fourth embodiment)
<Robot>
Next, a schematic configuration of an example of a robot including any of the gripping devices of the above embodiment will be described. FIG. 6 is a schematic diagram illustrating a schematic configuration of an example of a robot according to the fourth embodiment.

  As shown in FIG. 6, the robot 100 according to the fourth embodiment includes a base 400, a pair of arms 200, a pair of arms 300, and the above-described gripping devices 1, 2, 3, 4 as a pair of robot hands. One of them. A pair of arms 300 are installed on both sides of the base 400, and each arm 300 and each arm 200 are connected by an indirect portion. Any one of the above-described gripping devices 1, 2, 3, and 4 is attached to the tip of each arm 200.

  According to the robot 100 according to the fourth embodiment, since any one of the above-described gripping devices 1, 2, 3, and 4 is provided, the object 50 is gripped in a stable state and carried to a predetermined place. Can do. Accordingly, since it is possible to prevent the object 50 from being missed or dropped during the transportation of the object 50, it is possible to provide the robot 100 that can reliably perform the work and reduce the work time. Note that the configuration of the robot 100 is not limited to the above-described configuration, and for example, can be configured to have various configurations such as a one-arm robot.

  The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied within the scope of the present invention. A modification will be described below.

(Modification 1)
In the gripping devices 1, 2, 3, and 4 of the above-described embodiments, the elastic bodies 12 are provided on the surfaces 11a, 11b, 11c, and 11d of the claw portions 10a and 10b. However, the present invention is not limited to such a configuration. For example, as in the gripping device 5 shown in FIG. 7A, the elastic body 14 may cover the entire claw portions 10 a and 10 b together with the pressure sensor 20. With such a configuration, since the surfaces of the claw portions 10a and 10b are not exposed, it is possible to prevent the object 50 from being damaged by contact of the corner portions of the claw portions 10a and 10b. Moreover, when the nail | claw parts 10a and 10b contact other equipment etc., the impact which nail | claw parts 10a and 10b receive can be relieved.

(Modification 2)
In the gripping devices 1, 2, 3, and 4 of the above-described embodiment, the object 50 is gripped at four positions by the pair of claw portions 10a and 10b having a V-shape. It is not limited. For example, like the gripping device 6 shown in FIG. 7B, one of the pair of claws is provided with a plate-like claw 16a, and the object 50 is gripped at three positions between the other claw 10b. It is good also as a structure. Even if it is such a structure, the effect similar to the holding | grip apparatus of embodiment mentioned above can be acquired.

(Modification 3)
In the gripping devices 1, 2, 3, and 4 according to the above-described embodiments, the claws 10a and 10b are provided with the elastic body 12. However, the present invention is not limited to such a configuration. The structure which is not equipped with the elastic body 12 in the nail | claw parts 10a and 10b may be sufficient. Even if it is such a structure, if the pressure sensor 20 is a sensor which has a pressure-sensitive material of an elastic body, it can also serve as the elastic body 12. Moreover, also when the target object 50 is comprised with the material which has an elastic body, and the material which has a softness | flexibility, it is good also as a structure which is not equipped with the elastic body 12 in the holding | grip apparatus 1,2,3,4.

(Modification 4)
In the gripping devices 1, 2, 3, and 4 according to the above-described embodiments, the claw portions 10a and 10b are provided with the pressure sensors 20 and 60. However, the present invention is not limited to such a configuration. The claw portions 10a and 10b may not be provided with the pressure sensors 20 and 60. Even with such a configuration, it is possible to confirm whether or not the object 50 is in the stable gripping position by optical detection using a camera or the like or by visual observation.

(Modification 5)
In the gripping devices 1, 2, 3, and 4 according to the above-described embodiments, the pressure sensors 20 and 60 include a sensor having an elastic pressure-sensitive material. However, the present invention is not limited to such a configuration. If the gripping devices 1, 2, 3, and 4 are provided with the elastic body 12, the pressure sensors 20 and 60 may be pressure sensors that do not have an elastic pressure-sensitive material. As such pressure sensors 20 and 60, for example, a capacitance type pressure sensor using a fluid such as silicon oil or liquid crystal for the intermediate layer 23, a diaphragm gauge that converts pressure applied to the diaphragm into an electric signal, or the like. A pressure element or an element that detects a change in inductance can be used.

(Modification 6)
In the gripping devices 1, 2, 3, and 4 of the above-described embodiments, the first electrodes 22 of the pressure sensors 20 and 60 are arranged in a total of 16 in 4 rows and 4 columns. However, the present invention is limited to such a configuration. Not. The number of the first electrodes 22 may be other than 16, or may be arranged other than in a matrix form.

(Modification 7)
In the gripping device 2 of the second embodiment, 16 pressure sensors 60 are provided on each surface 11 of the claw portions 10a and 10b. However, the present invention is not limited to such a configuration. The number of pressure sensors 60 provided on each surface 11 of the claw portions 10a and 10b may be any number as long as it is three or more.

  1, 2, 3, 4, 5, 6 ... gripping device, 10a, 10b ... pair of claws, 12, 12a, 12b, 12c, 12d ... elastic body, 20, 20a, 20b, 20c, 20d, 60 ... pressure Sensors, 30a, 30b, a pair of fingers, 50, an object, 70, 70a, 70b, a vibration unit, 100, a robot.

Claims (8)

A pair of claws that contact the object in at least three locations;
A pair of finger parts for supporting each of the pair of claw parts and applying a gripping force to the object through the claw parts,
A gripping device that applies the gripping force intermittently before gripping the object. The gripping device according to claim 1,
A gripping device comprising an elastic body at a position in contact with the object of the claw portion. The gripping device according to claim 2,
The gripping device, wherein the elastic body is a pressure sensor. The gripping device according to claim 3,
A gripping device comprising a plurality of the pressure sensors for each position in contact with the object. The gripping device according to claim 3 or 4,
The gripping device further comprising an elastic body that covers the pressure sensor. The gripping device according to claim 1,
A gripping device comprising: a vibrating portion that vibrates the claw when intermittently applying the gripping force. The gripping device according to claim 6,
A gripping device comprising a vibrating body in the claw portion as the vibrating portion.   A robot comprising the gripping device according to any one of claims 1 to 7.

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