JP7014497B2 - Gripping system - Google Patents

Description

The present invention relates to a gripping system.

A hand mechanism that is attached to a robot arm or the like and grips an object with a plurality of fingers has been developed. For example, Patent Document 1 discloses a robot device including a hand mechanism having a plurality of finger portions (multi-finger hand portion) and a robot arm to which the hand mechanism is attached to the tip.

Japanese Patent No. 550138

Picking robots often repeat the same movements at high frequency. When the object is repeatedly gripped in the same gripping mode, the load may be concentrated on some parts of the hand mechanism. Some parts that are heavily loaded in this way may have a shorter life than other parts. Then, the life of some parts is shortened, which may shorten the life of the hand mechanism as a whole.

The present invention has been made in view of various circumstances as described above, and an object thereof is to extend the life of the hand mechanism.

One aspect of the present invention is a gripping system for gripping an object by a hand mechanism having a plurality of finger portions, and the hand mechanism grips the object a predetermined number of times or more in the same gripping mode. Is a gripping system including a control device for gripping the object by changing the gripping mode of the hand mechanism to a gripping mode different from the same gripping mode.

According to the present invention, the life of the hand mechanism can be extended.

It is a figure which shows the schematic structure of the robot arm which concerns on embodiment. It is a perspective view of the hand mechanism which concerns on embodiment. It is a top view of the hand mechanism which concerns on embodiment. It is a side view of the finger part of the hand mechanism which concerns on embodiment. It is a figure which looked at the tip end side of the finger part of the hand mechanism which concerns on embodiment from the direction of the arrow A of FIG. It is a figure which shows the internal structure of the part near the connection part of the finger part in the base part, and the internal structure of the base end part and the 2nd joint part in a finger part of the hand mechanism which concerns on embodiment. It is a figure which shows the movable range of the 2nd joint part in the finger part of the hand mechanism which concerns on embodiment. It is a figure which shows the internal structure of the 1st joint part and the 2nd finger link part in the finger part of the hand mechanism which concerns on embodiment. It is a figure which shows the movable range of the 1st joint part in the finger part of the hand mechanism which concerns on embodiment. It is a figure which shows the arrangement of the pressure sensitive sensor on the tip end side of the 1st finger link part of the finger part of the hand mechanism which concerns on embodiment. It is a block diagram which shows each functional part included in the control apparatus which concerns on embodiment. It is a figure which shows the direct grip performed by the hand mechanism which concerns on embodiment. It is a figure when the arrangement of the finger part which concerns on an embodiment is seen from the upper side of an object. It is a figure when the arrangement of the finger part which concerns on an embodiment is seen from the upper side of an object. It is a figure when the arrangement of the finger part which concerns on an embodiment is seen from the upper side of an object. It is a figure when the arrangement of the finger part which concerns on an embodiment is seen from the upper side of an object. It is a figure when the arrangement of the finger part which concerns on an embodiment is seen from the upper side of an object. It is a flowchart of the gripping control executed by the hand system which concerns on embodiment. It is the first figure for demonstrating the tilting grip performed by the hand mechanism which concerns on embodiment. It is a 2nd figure for demonstrating the tilting grip performed by the hand mechanism which concerns on embodiment. It is a 3rd figure for demonstrating the tilting grip performed by the hand mechanism which concerns on embodiment. It is a 4th figure for demonstrating the tilting grip performed by the hand mechanism which concerns on embodiment. It is a 5th figure for demonstrating the tilting grip performed by the hand mechanism which concerns on embodiment. It is a flowchart of the gripping control executed by the hand system which concerns on embodiment. It is the first figure for demonstrating the shift grip performed by the hand mechanism which concerns on embodiment. It is a 2nd figure for demonstrating the shift grip performed by the hand mechanism which concerns on embodiment. It is the first figure which showed the state before and after changing the gripping mode by changing the angle of the 1st joint part and the 2nd joint part of the finger part which concerns on embodiment. It is a 2nd figure which showed the state before and after changing the gripping mode by changing the angle of the 1st joint part and the 2nd joint part of the finger part which concerns on embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to those alone.

The gripping system according to the present invention is a gripping system for gripping an object by a hand mechanism having a plurality of finger portions, and when the hand mechanism grips the object a predetermined number of times or more in the same gripping mode. Changes the gripping mode of the hand mechanism to a gripping mode different from the same gripping mode to grip the object.

According to the above configuration, it is possible to suppress the concentration of the load on the specific finger portion due to the specific finger portion repeating the same operation, so that the life of the entire gripping system can be extended.

<Embodiment>
Here, a case where the gripping system according to the present invention is applied to a robot arm will be described. The gripping system is a system for gripping an object to be gripped by using the hand mechanism 2 provided at the tip of the robot arm 1. FIG. 1 is a diagram showing a schematic configuration of a robot arm 1 according to the present embodiment. The robot arm 1 includes a hand mechanism 2, an arm mechanism 3, and a pedestal portion 4. A hand mechanism 2 is attached to one end of the arm mechanism 3. Further, the other end of the arm mechanism 3 is attached to the pedestal portion 4. The hand mechanism 2 includes a base portion 20 connected to the arm mechanism 3 and four finger portions 21 provided on the base portion 20. The detailed configuration of the hand mechanism 2 will be described later.

<Arm mechanism>
The arm mechanism 3 includes a first arm link portion 31, a second arm link portion 32, a third arm link portion 33, a fourth arm link portion 34, a fifth arm link portion 35, and a connecting member 36. Then, the base portion 20 of the hand mechanism 2 is connected to the first joint portion 30a formed on one end side of the first arm link portion 31 of the arm mechanism 3. The first joint portion 30a is provided with a motor (not shown) for rotating the hand mechanism 2 around the axis of the first arm link portion 31 with respect to the first arm link portion 31. The other end side of the first arm link portion 31 is connected to one end side of the second arm link portion 32 by the second joint portion 30b. The first arm link portion 31 and the second arm link portion 32 are connected so that their central axes intersect vertically. Then, in the second joint portion 30b, a motor for rotating the first arm link portion 31 with respect to the second arm link portion 32 around the axis of the second arm link portion 32 around the other end side. (Not shown) is provided. Next, the other end side of the second arm link portion 32 is connected to one end side of the third arm link portion 33 by the third joint portion 30c, and the third joint portion 30c is connected to the third arm link portion 33 with respect to the third arm link portion 33. A motor (not shown) for relatively rotating the second arm link portion 32 is provided.

Similarly, the other end side of the third arm link portion 33 is connected to one end side of the fourth arm link portion 34 by the fourth joint portion 30d, and the other end side of the fourth arm link portion 34 is the fifth joint. The portion 30e is connected to the fifth arm link portion 35. The fourth joint portion 30d is provided with a motor (not shown) for rotating the third arm link portion 33 relative to the fourth arm link portion 34. Further, the fifth joint portion 30e is provided with a motor (not shown) for rotating the fourth arm link portion 34 relative to the fifth arm link portion 35. Further, the fifth arm link portion 35 is connected to the connecting member 36 vertically arranged from the pedestal portion 4 by the sixth joint portion 30f. The fifth arm link portion 35 and the connecting member 36 are connected so that their central axes are coaxial with each other. The sixth joint portion 30f is provided with a motor (not shown) for rotating the fifth arm link portion 35 around the axis of the fifth arm link portion 35 and the connecting member 36. By configuring the arm mechanism 3 in this way, the arm mechanism 3 can be a mechanism having 6 degrees of freedom.

<Hand mechanism>
Next, the configuration of the hand mechanism 2 will be described with reference to FIGS. 2 to 10. FIG. 2 is a perspective view of the hand mechanism 2. FIG. 3 is a top view of the hand mechanism 2. Further, as shown in FIGS. 2 and 3, in the hand mechanism 2, the four finger portions 21 on the base portion 20 are centered on the axis in the longitudinal direction of the hand mechanism 2 (the direction perpendicular to the paper surface in FIG. 3). They are arranged at equal intervals (that is, 90 deg intervals) on the circumference of the circle. Further, all four finger portions 21 have the same structure and the same length. However, the operation of each finger portion 21 is controlled independently.

4 to 10 are views for explaining the configuration of the finger portion 21 of the hand mechanism 2 and the driving mechanism thereof. FIG. 4 is a side view of the finger portion 21. Note that FIG. 4 shows the base portion 20 in a transparent state, and also shows the internal structure of a part of the finger portion 21 located inside the base portion 20. Further, FIG. 5 is a view of the tip end side of the finger portion 21 as viewed from the direction of arrow A in FIG.

The finger portion 21 has a first finger link portion 211, a second finger link portion 212, and a base end portion 213. Then, the base end portion 213 of the finger portion 21 is connected to the base portion 20. Here, as shown by an arrow in FIG. 3, the base end portion 213 is rotatably connected to the base portion 20 about the axis in the longitudinal direction of the finger portion 21 (the direction perpendicular to the paper surface in FIG. 3). There is. Further, in the finger portion 21, one end of the second finger link portion 212 is connected to the base end portion 213. A second joint portion 23 is formed at the connection portion between the second finger link portion 212 and the proximal end portion 213.

Then, the drive mechanism of the proximal end portion 213 and the drive mechanism of the second joint portion 23 will be described with reference to FIG. FIG. 6 is a diagram showing an internal structure of a portion of the base portion 20 near the connection portion of the finger portion 21 and an internal structure of the base end portion 213 and the second joint portion 23 of the finger portion 21. As shown in FIG. 6, inside the base portion 20, the gear 65 connected to the rotating shaft of the base end portion 213, which rotates the entire finger portion 21, and the rotating shaft of the third motor 53 are connected to the inside. A gear 66 is provided. Then, the gear 65 and the gear 66 are in mesh with each other. With such a configuration, when the third motor 53 rotates, the rotational force thereof is transmitted to the rotating shaft of the base end portion 213 via the two gears 65 and 66. That is, the entire finger portion 21 can be rotationally driven by the third motor 53.

Further, inside the second joint portion 23, a worm wheel 63 and a worm 64 meshed with the worm wheel 63 are provided. Then, the worm wheel 63 is connected to the rotation axis of the second finger link portion 212 in the second joint portion 23. Further, the worm 64 is connected to the rotation shaft of the second motor 52 provided inside the base portion 20. With such a configuration, when the second motor 52 is rotationally driven, the rotational force is transmitted to the rotation axis of the second finger link portion 212 by the worm 64 and the worm wheel 63, and the second finger link portion 212 is the base end portion. It will be rotationally driven relative to 213. At this time, the driving force of the second motor 52 and the driving force of the third motor 53 are configured to be independently transmitted to the operating target. FIG. 7 is a diagram showing a movable range of the second joint portion 23 in the finger portion 21 realized by the driving force of the second motor 52. As shown in FIG. 7, the second joint portion 23 is formed so as to be flexible and extendable.

Next, in the finger portion 21, one end of the first finger link portion 211 is connected to the other end of the second finger link portion 212. The first joint portion 22 is formed at the connection portion between the first finger link portion 211 and the second finger link portion 212. The drive mechanism of the first joint portion 22 will be described with reference to FIG. FIG. 8 is a diagram showing the internal structure of the first joint portion 22 and the second finger link portion 212 in the finger portion 21. Inside the first joint portion 22, two bevel gears 61 and 62 that are fitted to each other are provided. Then, one bevel gear 61 is connected to the rotation shaft of the first finger link portion 211 in the first joint portion 22. Further, the other bevel gear 62 is connected to the rotating shaft of the first motor 51 provided inside the second finger link portion 212. With such a configuration, when the first motor 51 is rotationally driven, the rotational force is transmitted to the rotating shaft of the first finger link portion 211 by the two bevel gears 61 and 62, and the first finger link portion 211 is the second. It will be rotationally driven relative to the finger link portion 212. FIG. 9 is a diagram showing a movable range of the first joint portion 22 in the finger portion 21 realized by the driving force of the first motor 51. As shown in FIG. 9, the first joint portion 22 is formed so as to be flexible and extendable.

Further, as shown in FIGS. 2 and 4, in the present embodiment, in the finger portion 21, the finger portion 21 is based on the first joint portion 22 rather than the first finger link portion 211 on the tip end side of the first joint portion 22. The second finger link portion 212 on the portion 20 side (base end portion 213 side) is longer.

Further, as shown in FIGS. 2, 4, 5, and 10, in the present embodiment, the pressure sensor 70 is provided on the tip end side of the first finger link portion 211 of the finger portion 21. The pressure-sensitive sensor 70 is a sensor that detects an external force (pressure) acting on the tip end side of the first finger link portion 211. Further, as shown in FIG. 4, the pressure sensor 70 is provided on both sides of the wall surface 215 on the bending direction side and the wall surface 216 on the extension direction side of the first joint portion 22 on the tip end side of the first finger link portion 211. ing. Here, in the present embodiment, the wall surface 215 on the bending direction side of the first joint portion 22 on the tip end side of the first finger link portion 211 is formed in a curved surface shape. Therefore, as shown in FIG. 10, a plurality of pressure-sensitive sensors 70 are installed side by side along the curved surface shape on the wall surface 215 on the bending direction side of the first joint portion 22 on the tip end side of the first finger link portion 211. You may.

<Pedestal part>
Next, the configuration of the arm control device 42, which is the control device of the robot arm 1 arranged inside the pedestal portion 4, and the hand control device 43, which is the control device of the hand mechanism 2, will be described with reference to FIG. FIG. 11 is a block diagram showing each functional unit included in the arm control device 42 and the hand control device 43. The arm control device 42 includes each driver that generates a drive signal for driving each motor mounted on the arm mechanism 3 of the robot arm 1, and a drive signal from each driver is supplied to each corresponding motor. It is configured as follows. The arm control device 42 is a computer having an arithmetic processing unit and a memory, and has an arm control unit 420 and a motor state quantity acquisition unit 421 as functional units. Each functional unit is formed by executing a predetermined control program in the arm control device 42.

The arm control unit 420 is provided in each of the joint portions 30a, 30b, 30c, 30d, 30e of the arm mechanism 3 based on the object information acquired by the object information acquisition unit 430 described later, which is possessed by the hand control device 43. By controlling the motor, the arm mechanism 3 is moved, thereby moving the hand mechanism 2 to a predetermined grippable position suitable for gripping the object. Further, the motors provided in the joint portions 30a, 30b, 30c, 30d, and 30e of the arm mechanism 3 have an encoder that detects a state amount (rotational position, rotation speed, etc. of the rotation axis of the motor) related to each rotation state. (Not shown) is provided. Then, the state amount of each motor detected by the encoder of each motor is input to the motor state amount acquisition unit 421 of the arm control device 42. Then, the arm control unit 420 servo-controls each motor so that, for example, the hand mechanism 2 moves to the above-mentioned predetermined grippable position based on the state amount of each motor input to the motor state amount acquisition unit 421. do.

Next, the hand control device 43 includes each driver that generates a drive signal for driving each motor mounted on the hand mechanism 2, so that the drive signal from each driver is supplied to each corresponding motor. It is composed of. The hand control device 43 is a computer having an arithmetic processing unit and a memory, and has an object information acquisition unit 430, a motor state quantity acquisition unit 431, a sensor information acquisition unit 432, a direct grip control unit 433, and a determination unit 434 as functional units. It has a change unit 435, a first operation control unit 436, and a second operation control unit 437. Each functional unit is formed by executing a predetermined control program in the hand control device 43.

The hand control device 43 is configured to control the hand mechanism 2 moved to a predetermined grippable position based on the object information acquired by the object information acquisition unit 430. The object information acquisition unit 430 acquires object information, which is information about an object to be grasped by the hand mechanism 2. Here, the object information includes information on the shape, dimensions, and position of the object, and environmental information around the object (information on objects other than the object existing around the object, for example. , Information on the shape of the container in which the object is housed and the arrangement of the objects in the container). The object information acquisition unit 430 may acquire the object information input by the user. Further, when a visual sensor for capturing an image including an object is provided, the object information acquisition unit 430 may acquire the object information from the image captured by the visual sensor.

Further, the direct grip control unit 433 is a functional unit that causes the hand mechanism 2 to perform direct grip, which is one of the gripping forms of the object. Direct gripping means that at least two fingers of the finger portion 21 of the hand mechanism 2 are held as they are, that is, without changing the position or posture of the object placed before gripping. It is a form of gripping performed by bringing the object into contact with the object and sandwiching the object.

Next, the determination unit 434 is a functional unit that determines whether or not the arrangement state of the object to be gripped is the above-mentioned state in which direct gripping is possible. The determination unit 434 includes information on the shape and position of the object included in the object information acquired by the object information acquisition unit 430, and the relative positional relationship between the obstacle and the object around the object. It is determined whether or not the object can be directly gripped according to the environmental information. Further, the determination unit 434 is a functional unit that determines whether or not the object can be gripped in a form different from the direct grip when the arrangement state of the object to be gripped is a state in which the object to be gripped cannot be directly gripped. But also. The gripping form in this case is a gripping form realized by the first motion control unit 436 and the second motion control unit 437, which will be described later. Details of these will be described later. Further, the first motion control unit 436 and the second motion control unit 437 are functional units that cause the hand mechanism 2 to perform a gripping motion different from the direct gripping. Following the first operation executed by the first operation control unit 436, the second operation is executed by the second operation control unit. The details of the first operation and the second operation will also be described later. The changing unit 435 is a functional unit that changes the gripping mode of the object. The gripping mode indicates a mode of operation of the hand mechanism 2 when the hand mechanism 2 grips an object, a mode of arrangement of each finger portion 21, and a mode of an angle of each joint portion of each finger portion 21. That is, if at least one of the operation of the hand mechanism 2, the arrangement of each finger portion 21, and the angle of each joint portion of each finger portion 21 is different, it can be said that the gripping mode is different. It should be noted that changing the gripping mode of the hand mechanism 2 includes operating the finger portion 21 that was not operating and stopping the finger portion 21 that was operating.

Then, in the hand control device 43, the first motor 51, which drives each finger portion 21 of the hand mechanism 2 for gripping the object, whether it is the above-mentioned direct grip or a grip having a form different from the direct grip, is the first. The two motors 52 and the third motor 53 are controlled based on the object information. Each of the first motor 51, each second motor 52, and each third motor 53 of the hand mechanism 2 has an encoder (rotational position, rotation speed, etc. of the rotation axis of the motor) that detects the state amount related to each rotation state. (Not shown) is provided. Then, the state quantities of the motors 51, 52, 53 detected by the encoders of the motors 51, 52, 53 are input to the motor state quantity acquisition unit 431. Then, the hand control device 43 servo-controls each motor 52, 52, 53 in each finger portion 21 based on the state quantity of each motor 51, 52, 53 input to the motor state quantity acquisition unit 431 to control the object. Grip.

Further, in the hand control device 43, the detection value of the pressure sensitive sensor 70 provided on the tip end side of each finger portion 21 of the hand mechanism 2 is input to the sensor information acquisition unit 432. Then, the hand control device 43 can detect the contact of the finger portion 21 with the object based on the detection value of the pressure sensitive sensor 70 of each finger portion 21 acquired by the sensor information acquisition unit 432, and the detection signal is used. It is also possible to control each of the motors 51, 52, 53 in each finger portion 21 based on this.

<Direct grip control>
The details of the direct grip by the hand mechanism 2 will be described with reference to FIG. The object 10 shown in FIG. 12 is placed alone on the floor surface and has a rectangular parallelepiped shape. Then, as shown in FIG. 12, it is assumed that the end surface 10a of the object 10 and the end surface 10b facing the end surface 10a are both exposed to such an extent that the finger portion 21 of the hand mechanism 2 can come into contact with the end surface 10a. In the present application, when the four finger portions 21 of the hand mechanism 2 and the first finger link portion 211 constituting the finger portion 21 are distinguished and identified for each finger portion, the reference numbers "21" and "211" are used. "A" to "D", which are subscripts for identification, shall be added to "", and if it is not necessary to distinguish and identify, the description of the subscript may be omitted. Further, the subscripts "A" to "D" are assigned to each finger portion in the clockwise order in the state of the arrangement of the finger portions 21 shown in FIG. Here, in the object 10, since the end face 10a and the end face 10b are exposed, the object 10 is viewed from the paired direction indicated by the white arrow in the drawing by the finger portion 21A and the finger portion 21C of the hand mechanism 2. It can be pinched and gripped. At this time, since the object 10 can be gripped without changing the posture or position of the object 10, the gripping form shown in FIG. 12 is directly gripped.

As shown in FIG. 12, in order to grip the object 10, it is necessary to sandwich the object 10 with at least two finger portions 21. When the hand mechanism 2 has four finger portions 21 as shown in FIG. 2, a plurality of combinations can be considered for the two finger portions 21 that grip the object 10. If the object 10 is repeatedly gripped using the same two finger portions 21, a load is repeatedly applied to a movable portion such as a motor or a gear for operating the two finger portions 21. Therefore, the two finger portions 21 used for gripping the object 10 deteriorate faster than the remaining two finger portions 21 that do not grip the object 10. If the deterioration of the specific finger portion 21 is accelerated in this way, the life of the entire system may be shortened.

FIG. 13 is a view when the arrangement of the finger portions 21 when gripping the object 10 by using two finger portions 21 out of the four finger portions 21 is viewed from above the object 10. As an embodiment in which the object 10 is supported by using two finger portions 21, an embodiment in which opposite finger portions 21 are used (FIGS. 13 (a) to 13 (b)) and an embodiment in which adjacent finger portions 21 are used (FIG. 13). (C)-(f)) can be considered. When the object 10 is gripped using the two finger portions 21, the two finger portions 21 used for gripping the object 10 are compared with the two finger portions 21 not used for gripping the object 10. The load on the device increases. In the direct gripping, the object 10 may be gripped by at least two finger portions 21, but the object 10 may be more stable by bringing more finger portions 21 into contact with the object 10 as described below. May be gripped.

14 and 15 are views of the arrangement of the finger portions 21 when gripping the object 10 using three finger portions 21 out of the four finger portions 21 when viewed from above the object 10. be. As an embodiment in which the object is supported by using the three finger portions 21, two finger portions 21 are arranged on the end surface 10a of the object 10, and one finger portion 21 is arranged on the end surface 10b facing the end surface 10a. Can be considered. In FIG. 14, two adjacent finger portions 21 are arranged on the end surface 10a of the object 10, and one finger portion 21 of the remaining two finger portions 21 is arranged on the end surface 10b facing the end surface 10a. The case is shown. In the gripping mode shown in FIGS. 14 (a) and 14 (c), the finger portions 21 used are the same, but the load applied to the finger portions 21 may differ due to the different arrangement of the finger portions 21. Further, in FIG. 15, two finger portions 21 facing each other are arranged on the end surface 10a of the object 10, and one finger portion 21 of the remaining two finger portions 21 is arranged on the end surface 10b facing the end surface 10a. Is shown. When the object 10 is gripped using the three fingers, the three fingers used for gripping the object 10 are more than the load applied to the one finger 21 not used for gripping the object 10. The load applied to the unit 21 becomes large.

Further, FIGS. 16 and 17 are views when the arrangement of the finger portions 21 when gripping the object 10 by using all four finger portions 21 is viewed from above the object 10. FIG. 16A shows a case where the finger portion 21A and the finger portion 21B are arranged on the end surface 10a of the object 10, and the remaining finger portion 21C and the finger portion 21D are arranged on the end surface 10b facing the end surface 10a. FIG. 16B shows a case where the finger portion 21A and the finger portion 21D are arranged on the end surface 10a of the object 10, and the remaining finger portion 21B and the finger portion 21C are arranged on the end surface 10b facing the end surface 10a. In the gripping modes shown in FIGS. 16A and 16B, the finger portions 21 used are the same, but the load applied to the finger portions 21 may differ due to the different arrangement of the finger portions 21. Further, FIG. 17 shows a case where one finger portion 21 is arranged on each of the four end faces of the object 10. As shown in FIG. 17, when there is a difference between the width (horizontal length in FIG. 17) and the depth (vertical length in FIG. 17) of the object 10, when the object 10 is gripped. Finger part 21A and finger part 21C, and finger part 21B
And, due to the difference in operation with the finger portion 21D, the load may be different between the finger portion 21A and the finger portion 21C and the finger portion 21B and the finger portion 21D.

Therefore, when the number of times the object 10 is continuously gripped in the same gripping mode becomes a predetermined number of times or more, the changing unit 435 changes the gripping mode and grips the object 10. For example, when gripping the object 10 using two fingers, the combination of the two fingers 21 that grips the object 10 is changed every time the object 10 is gripped by the same finger 21 a predetermined number of times. By doing so, the arrangement of the finger portion 21 with respect to the object 10 is changed. As a result, it is possible to prevent the load applied to the specific finger portion 21 from becoming large. The predetermined number of times referred to here is preset as the number of times that the life of the hand mechanism 2 can be extended. Although the predetermined number of times may be set to one, the motor is driven by the hand mechanism 2 or the arm mechanism 3 when the gripping mode is switched, so that a load is applied to the motor, the gears, and the members supporting them. Therefore, the predetermined number of times may be set in consideration of the load when switching the gripping mode.

The changing unit 435 selects a combination of finger portions 21 capable of gripping the object 10 based on the object information acquired by the object information acquisition unit 430. Further, the changing unit 435 directly instructs the gripping control unit 433 to grip the object 10 with the combination of the selected finger units 21. Then, every time the number of times the object 10 is continuously gripped in the same gripping mode reaches a predetermined number of times, the changing unit 435 reselects the combination of the finger portions 21 so as to change the combination of the finger portions 21. The changing unit 435 directly instructs the gripping control unit 433 to grip the object 10 with the combination of the finger portions 21 selected again. In this way, the changing unit 435 changes the combination of the finger portions 21 each time the number of times the object 10 is continuously gripped in the same gripping mode reaches a predetermined number of times. As a result, the gripping mode of the hand mechanism 2 can be changed to a different gripping mode, so that it is possible to prevent an excessive load from being applied to the specific finger portion 21.

Here, based on FIG. 18, the gripping control of the object 10 by the gripping system using the hand mechanism 2 mounted on the robot arm 1 will be described. FIG. 18 is a flowchart showing a flow of grip control when directly gripping. This gripping control is realized by executing a predetermined control program in the arm control device 42 and the hand control device 43. The gripping control related to the direct gripping is executed when the determination unit 434 determines that the object 10 can be directly gripped.

In S101, the changing unit 435 determines whether or not the number of times of gripping in the same embodiment is continuously equal to or more than a predetermined number of times. The changing unit 435 counts the number of grips in the same mode, and the number of grips is compared with a preset predetermined number. If an affirmative determination is made in S101, the process proceeds to S102, and if a negative determination is made, the process proceeds to S103.

In S102, the gripping mode is changed. In S102, the changing unit 435 newly selects the combination of the finger portions 21 and directly instructs the gripping control unit 433 to grip the object 10 using the newly selected finger portion 21. , The gripping mode is changed. The combination of the finger portions 21 that grip the object 10 may be selected according to the order stored in the memory in advance, or may be randomly selected. Further, when the finger portion 21 that grips the object 10 and the finger portion 21 that does not grip the object 10 exist, at least a part of the finger portion 21 that grips the object 10 and the object 10 are used. The finger portion 21 that is not gripped may be replaced.

In S103, the gripping mode is maintained. In this case, if the changing unit 435 does not directly instruct the gripping control unit 433, the program may be programmed so that the previous gripping mode is maintained, or the changing unit 435 has the same gripping mode as the previous time. By directly instructing the gripping control unit 433 to be, the program may be programmed so that the previous gripping mode is maintained.

When the processing of S102 or S103 is completed, the process proceeds to S104. Then, in S104, direct gripping by the hand mechanism 2 is carried out. After the processing of S104, this control ends. In this way, since the gripping mode is changed every time the same gripping mode is continuously performed a predetermined number of times when the direct gripping is performed, it is possible to suppress the concentration of the load on the specific finger portion 21, so that the gripping system as a whole can be used. The life can be extended. Further, since the finger portions 21 are arranged on the base portion 20 at equal angular intervals and all the finger portions 21 have the same structure and the same length, the hand mechanism 2 is provided with respect to the first arm link portion 31. The arrangement of the finger portion 21 with respect to the object 10 can be changed by rotating the arm link portion 31 around the axis. Therefore, the gripping mode can be easily changed.

<Tilt grip control>
When the object 10 is arranged in a state where it cannot be directly gripped, the object 10 is gripped in a form different from the direct grip. The gripping form in this case is a gripping form realized by the first motion control unit 436 and the second motion control unit 437. For example, when an obstacle (for example, a container for accommodating an object) is located around the object 10, it is difficult to arrange the two finger portions 21 on the opposite end faces of the object 10. In some cases. Even in such a case, the finger portion 21 of the hand mechanism 2 comes into contact with the object 10 and acts on the object 10 to tilt and tilt the object 10 so that the object 10 can be gripped. In some cases. This tilting operation is an operation for exposing the end face to the extent that the finger portion 21 of the hand mechanism 2 can come into contact with the facing end face, and is the first operation executed by the first movement control unit 436. Corresponds to. In the present application, the gripping operation performed after the tilting operation of the object 10 is referred to as tilting gripping. This tilt grip corresponds to the second motion executed by the second motion control unit 437.

The determination unit 434 provides information on the shape and position of the object 10 included in the object information acquired by the object information acquisition unit 430, and the relative positional relationship between the obstacle and the object around the object 10. It is determined whether or not the object 10 can be tilted and gripped according to the environmental information such as.

Tilt grip will be described with reference to FIGS. 19 and 20. The object 10 is in contact with a non-object 10'which is an object having the same shape as the object 10 but is not an object to be grasped. The surface of the surface of the object 10 that is exposed so that the finger portion 21 of the hand mechanism 2 can be contacted is defined as the contactable surface. Further, the surface of the object 10 that is not exposed so that the finger portion 21 of the hand mechanism 2 can be contacted at the time of determination by the determination unit 434, but is an object that can be used for gripping by the finger portion 21 of the hand mechanism 2. The surface of the object 10 is an unexposed surface.

The first motion control unit 436 brings the first finger link portion 211A of the finger portion 21A into contact with the contactable surface 101 which is the upper surface of the object 10. At this time, the other finger portions 21B to 21D are not in contact with the object 10. Then, while maintaining the contact state between the finger portion 21A and the contactable surface 101, the first motion control unit 436 drives and controls the finger portion 21A and exerts a force on the object 10 to pull the object 10 toward the front side. Let me. Therefore, as shown in FIG. 20, the object 10 is tilted so that the upper portion thereof approaches the floor surface side with a part of the bottom surface in contact with the floor surface as the center.

Then, as a result of this tilting operation, the unexposed surface 102, which is the back surface of the object 10 that was in contact with the non-object 10'in the arranged state before gripping, is exposed, and the non-exposed surface 102 and the non-object 10 are exposed. A space is formed between it and. The space becomes larger as the object 10 is tilted. Then, the size of the space is set so that the finger portion 21B and the finger portion 21D different from the finger portion 21A of the hand mechanism 2 can enter the space formed between the non-exposed surface 102 and the non-object 10'. If it can be secured, the tilting operation (first operation) by the first operation control unit 436 is stopped. Such a space sufficient for the finger portion 21B and the finger portion 21D to enter is hereinafter referred to as an entry space.

When the tilting motion by the first motion control unit 436 is stopped, the state in which the finger portion 21A is in contact with the contactable surface 101 is maintained. Therefore, the non-exposed surface 102 is sufficiently exposed, and an entry space is secured between the object 10 in the tilted state and the adjacent non-object 10'. After that, the gripping operation (second operation) of the object 10 is performed. This gripping motion is a gripping mode in which the posture of the object 10 before the gripping control is started is changed by the tilting motion, and is a tilting grip different from the direct grip shown in FIG.

Tilt gripping will be specifically described with reference to FIGS. 21A to 21C. It should be noted that FIGS. 21A to 21C show the same state in which the hand mechanism 2 grips the object 10 by tilting grip from different viewpoints. 21A is a view from the direction in which the unexposed surface 102 of the object 10 can be seen, FIG. 21B is a view of the object 10 from the side, and FIG. 21C is a direction in which the front surface 103 of the object can be seen. It is a figure from.

In the tilted grip, the first finger link portion 211B of the finger portion 21B and the first finger link portion 211D of the finger portion 21D enter the approach space formed between the object 10 and the adjacent non-object 10'. The two-finger link portion is brought into contact with the unexposed surface 102, and the first finger link portion 211C of the finger portion 21C is brought into contact with the front surface 103 of the object 10. That is, in the tilted grip, the fingers other than the finger portion 21A of the hand mechanism 2 used to support the tilted object 10 from the front and back in the tilted state are used, and the object 10 is tilted. Stable grip is realized. Alternatively, the unexposed surface 102 may be brought into contact with the first finger link portion of one finger portion 21, and the front surface 103 may be brought into contact with the first finger link portion of the remaining two finger portions 21. .. Alternatively, the unexposed surface 102 is brought into contact with the first finger link portion of one finger portion 21, and the front surface 103 is brought into contact with the first finger portion 21 of one of the remaining two finger portions 21. The finger link portion may be brought into contact with the finger link portion.

Further, in order to grip the object more stably in the tilted grip, as shown in FIG. 21B, the first link of the finger portion 21 on the non-exposed surface 102 side when the object 10 is viewed from the side. It is preferable that the finger portion and the first link finger portion of the finger portion 21 on the front surface 103 side are substantially opposed to each other. Further, as shown in FIGS. 21A to 21C, when tilting and gripping with three fingers, the action points of one finger 21C are two when viewed from the unexposed surface 102 or the front surface 103. It is preferable that each finger portion 21 comes into contact with the object so as to be located between the respective points of action of the finger portions 21B and the finger portions 21D.

When the object 10 is tilted and gripped, the hand mechanism 2 can move the object 10 to a desired position while gripping the object 10. As a result, the tilt grip control is completed.

In this way, in the tilt grip control, even if the object 10 is arranged in a state where it cannot be directly gripped, the finger portion 21A of the hand mechanism 2 is brought into contact with the contactable surface 101 to change the posture of the object 10. Then, the remaining finger portions 21B to 21D realize the tilted grip of the object 10.

Then, in the case of tilting gripping, the gripping mode is changed every time the tilted gripping is continuously performed a predetermined number of times in the same gripping mode. At that time, at least one of the first operation and the second operation is changed. When the finger portion 21 involved in the second movement is changed, the arrangement of the finger portion 21 at the time of tilting grip is changed. For example, when the gripping mode of the object 10 after the tilting motion is shown in FIG. 13 (a), the finger portion 21B or the finger portion 21D is used for the first motion, and the finger portion is used for the second motion. 21A and finger 21C are used. In this case, when the gripping mode is changed, the finger portion 21 used for the first operation may be alternately changed between the finger portion 21B and the finger portion 21D. At this time, the finger portion 21A and the finger portion 21D used for the second operation do not have to be changed. Further, when changing the gripping mode, the finger portion 21 used for the first movement is used for the second movement, and one of the finger portions 21 used for the second movement is used for the first movement or is not moved. You may. Further, when changing the gripping mode, the finger portion 21 used for the first motion and the second motion may be randomly changed.

Further, when the gripping mode of the object 10 after the tilting motion is in the state shown in FIG. 14 or 15, the finger portion 21 used for the first motion is used for the second motion when the gripping mode is changed. Therefore, one finger portion 21 of the finger portions 21 used for the second motion may be used for the first motion. At this time, the arrangement of the finger portion 21 used for the second operation may be changed. Further, when changing the gripping mode, the finger portion 21 used for the first operation may not be changed, but only the arrangement of the finger portion 21 used for the second operation may be changed. Further, when changing the gripping mode, the finger portion 21 used for the first motion and the second motion may be randomly changed.

Such a change in the gripping mode is performed so that the load applied to the specific finger portion 21 does not become excessively large. For example, the finger portions 21 used for the first operation and the second operation may be changed in the order stored in the memory in advance, or may be changed at random. FIG. 22 is a flowchart showing a flow of grip control when tilt gripping is performed. This gripping control is realized by executing a predetermined control program in the arm control device 42 and the hand control device 43. The gripping control related to the tilted grip is executed when the determination unit 434 determines that the object 10 cannot be directly gripped and can be tilted and gripped.

In S201, the changing unit 435 determines whether or not the number of times of gripping in the same embodiment is continuously equal to or more than a predetermined number of times. The changing unit 435 counts the number of grips in the same mode, and the number of grips is compared with a preset predetermined number. If an affirmative determination is made in S201, the process proceeds to S202, and if a negative determination is made, the process proceeds to S203.

In S202, the gripping mode is changed. In S202, the changing unit 435 newly selects the combination of the finger portions 21 in the first motion and the second motion, and the first motion control is performed so that the object 10 is gripped by using the newly selected finger portion 21. By instructing the unit 436 and the second operation control unit 437, the gripping mode is changed. The gripping mode may be changed according to a predetermined order, or may be changed at random. Further, when changing the gripping mode, the number of finger portions 21 used for gripping the object 10 may be changed. Further, the gripping mode may be changed by changing the tilting direction of the object 10 in the first operation. If there is a finger portion 21 that grips the object 10 and a finger portion 21 that does not grip the object 10, at least a part of the finger portion 21 that grips the object 10 and the finger portion 21 that does not grip the object 10 are not gripped. The finger portion 21 may be replaced. In this case, the object 10 may be tilted by the finger portion 21 that does not grip the object 10.

In S203, the gripping mode is maintained. In this case, if the change unit 435 does not instruct the first operation control unit 436 and the second operation control unit 437, the program may be programmed so that the previous gripping mode is maintained. By instructing the first motion control unit 436 and the second motion control unit 437 so that the unit 435 has the same gripping mode as the previous time, the program may be programmed so that the previous gripping mode is maintained. ..

When the processing of S202 or S203 is completed, the process proceeds to S204. Then, in S204, the first operation is performed by the first operation control unit 436, then in S205, the second operation is performed by the second operation control unit 437, and then this flowchart ends. In this way, when the tilted grip is performed, the gripping mode is changed every time the same gripping mode is continuously performed a predetermined number of times, so that it is possible to suppress the concentration of the load on the specific finger portion 21, and thus the gripping system as a whole. The life can be extended.

When both direct gripping and tilted gripping can be adopted as the gripping mode of the object 10, the changing unit 435 changes the gripping mode from direct gripping to tilted gripping when changing the gripping mode. Alternatively, the tilted grip may be changed to a direct grip. In this way, by changing the gripping form between direct gripping and tilted gripping, the movements of the finger portion 21 that grips the object 10 and the finger portion 21 change, so that the load is concentrated on the specific finger portion 21. Can be suppressed. Whether or not both direct gripping and tilting gripping are possible is determined by the determination unit 434 based on the object information. Then, every time the same gripping mode is continuously performed a predetermined number of times, the changing unit 435 changes the gripping mode from direct gripping to tilted gripping or from tilted gripping to direct gripping. At this time, the change of the gripping mode in the direct grip and the change of the gripping mode in the tilted grip may be combined. For example, the gripping mode of the direct grip may be changed a plurality of times and then changed to the tilted grip, and the gripping mode of the tilted grip may be changed a plurality of times and then changed to the direct grip. Further, for example, every time the same gripping mode is continuously performed a predetermined number of times, the gripping mode may be randomly selected from direct gripping and tilted gripping.

<Shift grip control>
When the object 10 is arranged in a state where it cannot be directly gripped, it is conceivable to perform the staggered grip described below. The shift grip will be described with reference to FIGS. 23 and 24. In both figures, the hand mechanism 2 has two fingers, a finger portion 21A and a finger portion 21B, but a finger portion may be further provided. These fingers have the same configuration as described above, but as shown in FIG. 3, when the hand mechanism 2 is viewed from above, each finger 21 is a length of the hand mechanism 2. They are arranged at equal angular intervals (that is, 180 deg intervals) on the circumference centered on the axis of direction. In FIGS. 23 and 24, the object 10 having a rectangular parallelepiped shape is arranged on the floor surface, but the non-object 10'is placed so as to be in contact with the side of the object 10. Further, since there is an obstacle (not shown) on the side of the object 10 (front and back side in the figure), it is assumed that the object 10 cannot be moved in that direction. In such a case, it is determined that the object 10 cannot be directly gripped by the determination by the determination unit 434. The determination is made based on the object information acquired by the object information acquisition unit 430.

When the determination unit 434 determines that the object 10 cannot be directly gripped, a shift grip different from the direct grip is performed. The shift gripping is a form of gripping performed after the object 10 is made into a grippable state by shifting the object 10 while pressing it against an object different from the object and changing the position of the object 10. That is, the staggered grip is a form of grip performed when the object 10 cannot be directly gripped like the tilt grip, and the difference from the tilt grip is that the tilt grip changes the posture of the object 10. While a grippable state is formed, the staggered grip forms a grippable state by changing the position of the object 10. Even in the shift grip, the shift grip is realized by executing the first motion by the first motion control unit 436 and the second motion by the second motion control unit 437 using the contactable surface and the non-exposed surface. Will be done.

First, of the surface of the object 10 exposed so that the finger portion 21 of the hand mechanism 2 can be contacted, the object 10 is moved up (moved in the direction of the white arrow in FIG. 23). Therefore, as a surface that enables the operation of pressing the object 10 against the non-object 10', the side surface of the object 10 opposite to the contact surface with the non-object 10'is selected as the contactable surface 101. ..

Further, when the object 10 is moved up in this way, it is the side surface of the object 10 that comes into contact with the non-object 10', and is not exposed so that the finger portion 21 can be touched before the object 10 is moved up. The sides will be exposed so that they can be touched. Then, the finger portion 21 is brought into contact with the exposed side surface, and the object 10 can be gripped by the finger portion in contact with the contactable surface 101 as shown in FIG. 24. Therefore, the unexposed side surface of the object 10 is selected as the unexposed surface 102. At this time, the exposed surface that is paired with the non-exposed surface and enables the object 10 to be shifted and gripped is the side surface (contactable surface 101) of the object 10.

By specifying the contactable surface 101 and the non-exposed surface 102 in this way, as the first operation, the first finger link portion 211A of the finger portion 21A comes into contact with the contactable surface 101, and the object 10 is not targeted. The object 10 is moved up in the direction of the white arrow in FIG. 23 while being pressed against the object 10'. As a result, the position of the object 10 rises, and the unexposed surface 102 is exposed so that the first finger link portion 211B of the finger portion 21B can come into contact with the non-exposed surface 102. In FIG. 24, the portion of the non-exposed surface 102 exposed by the shifting operation is referred to by “1020”. It should be noted that the non-object 10'may be pressed by the finger portion 21B so as not to move while the shifting operation is being performed. Then, the shifted state of the object 10 is maintained. Next, as a second operation, the first finger link portion 211B of the finger portion 21B is brought into contact with the exposed portion 1020 of the unexposed surface 102 of the object 10 in the displaced state. Then, together with the first finger link portion 211A of the finger portion 21A that is already in contact with the contactable surface 101, the first finger link portion 211B sandwiches and grips the object 10. In this way, it is possible to realize the gripping of the object 10 without being affected by the situation in which the object 10 is arranged as much as possible. Therefore, it is possible to grip the object extremely efficiently and move the object after gripping.

It should be noted that the shift gripping is not only a gripping mode accompanied by an operation of shifting the gripping object upward as shown in FIGS. 23 and 24 described above, but also an operation of shifting the gripping object sideways (lateral direction of the gripping object). Also includes a gripping form accompanied by. For example, in an arrangement in which a plurality of objects are stacked so that they cannot be directly gripped, if the exposed surface of the uppermost gripping object is substantially parallel to the bottom surface of the storage container, the gripping object is used. Shift grip may be realized by shifting to the side and bringing the fingers of the hand mechanism into contact with the pair of side surfaces of the gripping object exposed by the shifting operation.

The determination unit 434 provides information on the shape and position of the object 10 included in the object information acquired by the object information acquisition unit 430, and the relative positional relationship between the obstacle and the object around the object 10. It is determined whether or not the object 10 can be shifted and gripped according to the environmental information such as.

Then, in the case of performing the shift grip, the grip mode is changed every time the shift grip is continuously performed a predetermined number of times in the same grip mode. At that time, at least one of the first operation and the second operation is changed. For example, in FIGS. 23 and 24, the finger portion 21 that contacts the contactable surface 101 in the first operation and the finger portion 21 that contacts the exposed portion 1020 of the unexposed surface 102 in the second operation are continuously displaced and gripped. And replace it every time it is done a predetermined number of times. Here, since the finger portion 21 that contacts the contactable surface 101 in the first operation and the finger portion 21 that contacts the exposed portion 1020 of the non-exposed surface 102 in the second operation, the applied load is also different. Therefore, if the staggered grip in the same gripping mode is continued, an excessive load may be applied to the specific finger portion 21. On the other hand, the load can be dispersed by changing the arrangement of the finger portions 21 with respect to the object 10 every time the shift grip is continuously performed a predetermined number of times.

Further, in the case of having four finger portions 21 as shown in FIG. 3, when the gripping mode of the object 10 at the time of shifting gripping is in the state shown in FIG. 13, each time the shifting gripping is continuously performed a predetermined number of times, The finger portion 21 that comes into contact with the object 10 in the first movement (hereinafter, also referred to as the finger portion 21 according to the first movement), and the finger portion 21 that first contacts the object 10 in the second movement (hereinafter, the second movement). (Also referred to as finger portion 21) according to the above, at least one of them is changed. The changing unit 435 selects a combination of the finger unit 21 related to the first operation and the finger unit 21 related to the second operation based on the object information acquired by the object information acquisition unit 430. Further, the changing unit 435 directly instructs the gripping control unit 433 to grip the object 10 with the combination of the selected finger units 21. and,
The changing unit 435 reselects the combination of the finger portions 21 so that the combination of the finger portions 21 is changed each time the number of times the object 10 is continuously gripped in the same gripping mode reaches a predetermined number of times. The changing unit 435 directly instructs the gripping control unit 433 to grip the object 10 with the combination of the finger portions 21 selected again. In this way, every time the number of times the object 10 is continuously gripped in the same gripping mode reaches a predetermined number of times, the changing unit 435 changes the combination of the finger portion 21 related to the first movement and the finger portion 21 related to the second movement. change. As a result, it is possible to prevent a load from being applied to the specific finger portion 21.

Further, in the case of having four finger portions 21 as shown in FIG. 3, a gripping mode in which two finger portions 21 according to the first operation and one finger portion 21 according to the second operation can be considered. In addition, there is a gripping mode in which the number of finger portions 21 related to the first movement is one and the number of finger portions 21 related to the second movement is two, and the number of finger portions 21 related to the first movement is two and the second movement is performed. A gripping mode in which the number of finger portions 21 according to the above is two is also conceivable. Even in these cases, at least one of the first operation and the second operation is changed every time the shift grip is continuously performed a predetermined number of times. As a result, it is possible to prevent a load from being applied to the specific finger portion 21.

Such a change in the gripping mode is performed so that the load applied to the specific finger portion 21 does not become excessively large. For example, the finger portion 21 related to the first movement and the finger portion 21 related to the second movement may be changed in the order stored in the memory in advance, or may be changed randomly. The gripping control at this time can be performed in the same manner as the gripping control shown in FIG. At that time, in S202, the changing unit 435 newly selects a combination of the finger portion 21 related to the first movement and the finger portion 21 related to the second movement, and the object is used by using the newly selected finger portion 21. By instructing the first motion control unit 436 and the second motion control unit 437 to grip the 10, the gripping mode is changed.

In this way, since the gripping mode is changed every time the same gripping mode is continuously performed a predetermined number of times when the staggered grip is performed, it is possible to suppress the concentration of the load on the specific finger portion 21, and thus the gripping system as a whole. The life can be extended.

When both the shifted grip and the tilted grip can be adopted as the gripped form of the object 10, the changing unit 435 changes the gripped form from the shifted grip to the tilted grip when the gripping mode is changed. Alternatively, the tilted grip may be changed to the shifted grip. In this way, by changing the gripping form between the shifted grip and the tilted grip, the movements of the finger portion 21 that grips the object 10 and the finger portion 21 change, so that the load is concentrated on the specific finger portion 21. Can be suppressed. Whether or not both shift grip and tilt grip are possible is determined by the determination unit 434 based on the object information. Then, every time the same gripping mode is continuously performed a predetermined number of times, the changing unit 435 changes the gripping mode from a shifted grip to a tilted grip or from a tilted grip to a shifted grip. At this time, the change of the gripping mode in the shift grip and the change of the gripping mode in the tilted grip may be combined. For example, the gripping mode of the tilted grip may be changed a plurality of times and then changed to the tilted grip, and the gripping mode of the tilted grip may be changed a plurality of times and then changed to the tilted grip. Further, for example, the gripping mode may be randomly selected from the staggered gripping and the tilted gripping mode every time the same gripping mode is continuously used a predetermined number of times. It should be noted that the case where any of direct gripping, staggered gripping, and tilted gripping can be adopted as the gripping mode of the object 10 can be similarly considered.

<Other gripping modes>
The number of finger portions 21 of the hand mechanism 2 is not limited to the number of finger portions 21 in the above description regardless of the gripping mode of direct gripping, tilted gripping, or offset gripping. If the number of finger portions 21 is two or more, the finger portions 21 are arranged on the base portion 20 at equal angular intervals, and all the finger portions 21 have the same structure and the same length, the first arm link portion Since the arrangement of the finger portion 21 with respect to the object 10 can be changed only by rotating the hand mechanism 2 with respect to the 31 around the axis of the first arm link portion 31, it becomes easy to change the gripping mode. Further, the mode of gripping the object 10 is not limited to the mode described above. Further, even if the arrangement of the finger portions 21 with respect to the object 10 is the same, if the directions of the loads applied to the finger portions 21 are different, different gripping modes may be considered. Further, even if the arrangement of the finger portions 21 with respect to the object 10 is the same, if the movements of the finger portions 21 until the finger portions 21 are arranged are different, different gripping modes may be considered.

In the above description, the gripping mode is changed by changing the arrangement of the finger portion 21 that grips the object 10 or replacing the finger portion 21 that grips the object 10, but instead of this, FIG. 25 And as shown in FIG. 26, the gripping mode can also be changed by changing the angles of the first joint portion 22 and the second joint portion 23 of the finger portion 21 when gripping the object 10. Here, FIGS. 25 and 26 are views showing a state before and after changing the gripping mode by changing the angles of the first joint portion 22 and the second joint portion 23 of the finger portion 21. The hand mechanism 2 shown in both figures has the same structure as the hand mechanism 2 shown in FIGS. 23 and 24. The object 10 shown in FIGS. 25 and 26 is placed alone on the floor surface and has a rectangular parallelepiped shape, and the hand mechanism 2 directly grips the object 10. In FIGS. 25 and 26, the hand mechanism 2 has two fingers, a finger portion 21A and a finger portion 21B, but may further have a finger portion.

The hand mechanism 2 shown in FIGS. 25 and 26 grips the same object 10, but the angles of the first joint portion 22 and the second joint portion 23 of the finger portion 21 are different. That is, the angle at which the first joint portion 22 bends and the angle at which the second joint portion 23 extends are larger in the gripping mode shown in FIG. 25 than in the gripping mode shown in FIG. 26. In this way, the object 10 can be gripped even if the angles of the first joint portion 22 and the second joint portion 23 are changed. For example, when the number of times the object 10 is continuously gripped in the gripping mode shown in FIG. 25 becomes a predetermined number of times or more, the gripping mode shown in FIG. 26 is changed to grip the object 10. Similarly, when the number of times the object 10 is continuously gripped in the gripping mode shown in FIG. 26 becomes a predetermined number of times or more, the gripping mode shown in FIG. 25 is changed to grip the object 10. In this way, the angles of the first joint portion 22 and the second joint portion 23 of the finger portion 21 can be changed each time the object 10 is continuously gripped a predetermined number of times or more in the same gripping mode.

Even when the gripping mode is changed by changing the angles of the first joint portion 22 and the second joint portion 23, the gripping control shown in FIG. 18 can be applied. However, in S102, the changing portion 435 newly selects a combination of angles of the first joint portion 22 and the second joint portion 23. The gripping mode is changed by instructing the changing unit 435 directly to the gripping control unit 433 so that the object 10 is gripped at the angles of the newly selected first joint portion 22 and the second joint portion 23. To. The combination of the angles of the first joint portion 22 and the second joint portion 23 when gripping the object 10 is not limited to two as shown in FIGS. 25 and 26, and may be three or more. Further, the angles of the first joint portion 22 and the second joint portion 23 may be changed stepwise or steplessly. The combination of angles may be selected according to the order stored in the memory in advance, or may be randomly selected. Further, in the above description, the case of direct gripping has been described, but even in the case of tilted gripping, the gripping mode can be changed by changing the angle of each joint portion during the first movement or the second movement. can.

In this way, by changing the angles of the first joint portion 22 and the second joint portion 23 of the finger portion 21 every predetermined number of times to grip the object 10, the first joint portion 22 and the second joint portion 23 can be gripped. Since the direction of the applied force can be changed and the range of use of each gear can be changed, it is possible to suppress the concentration of the load on a specific portion of some members. Therefore, it is possible to prevent the life of some members from being excessively shortened, and thus it is possible to extend the life of the gripping system as a whole.

1 ... Robot arm, 2 ... Hand mechanism, 20 ... Base part, 21 ... Finger part, 43 ... Hand control device

Claims (6)

A gripping system that grips an object by a hand mechanism having multiple fingers.
When the hand mechanism grips the object more than a predetermined number of times in the same gripping mode, the control for gripping the object by changing the gripping mode of the hand mechanism to a gripping mode different from the same gripping mode. Equipped with equipment
When the control device includes a finger portion that grips the object and a finger portion that does not grip the object among the plurality of finger portions, the control device includes at least a part of the finger portion that grips the object. By replacing the finger portion that does not grip the object, the gripping mode of the object is changed.
Gripping system. The control device changes the gripping mode of the object by changing the arrangement of the plurality of fingers with respect to the object.
The gripping system according to claim 1 . A gripping system that grips an object by a hand mechanism having multiple fingers.
When the hand mechanism grips the object more than a predetermined number of times in the same gripping mode, the control for gripping the object by changing the gripping mode of the hand mechanism to a gripping mode different from the same gripping mode. Equipped with equipment
The plurality of fingers each have a joint and
The control device changes the gripping mode of the object by changing the angle of the joint portion in a state where the object is gripped.
Gripping system. The control device tilts the object with a finger portion that does not grip the object, and then grips the object.
The gripping system according to any one of claims 1 to 3 . Further provided with a base portion in which the plurality of finger portions are arranged at equal intervals in the circumferential direction.
The plurality of fingers all have the same structure.
The gripping system according to any one of claims 1 to 4 . All the lengths of the plurality of fingers are the same,
The gripping system according to claim 5 .

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