JP5648353B2 - Robot hand and robot - Google Patents

Description

  The present invention relates to a technique for gripping an object by driving a robot hand.

Due to recent advances in robot technology, many industrial robots have been used in industrial product manufacturing sites. For example, in an assembly line for industrial products, multiple industrial robots are installed along the line, and the robot automatically assembles various parts to the product being manufactured that flows on the line. Improvement is widely done. Or when transporting parts assembled by such robots to the line side,
It is also widely performed to improve production efficiency as a whole factory by conveying parts using a robot.

As described above, industrial robots used in assembly lines and the like basically have only two types of movements: an operation of grasping an object and an operation of releasing the grasped object. Since there are various shapes and sizes, it is not easy to grasp and release these objects in the same way. Therefore, it is usual to prepare a plurality of types (robot hands) where the robot grips the object in accordance with the shape and size of the object, and use different robot hands suitable for the object. Note that a robot hand that performs a simple operation of simply grabbing and releasing an object in this way is sometimes called a “gripper-type robot hand (or simply a gripper)”.

However, when using multiple types of robot hands, it is necessary to change the robot hand each time the shape or size of the object changes. During that time, the assembly line must be stopped, which reduces production efficiency. End up. Therefore, in order to be able to handle objects of different shapes and sizes with the same robot hand, a robot hand having a plurality of fingers imitating a human hand has been developed (Patent Document 1). ). In this robot hand, a plurality of fingers are erected from a member corresponding to the palm, and each finger is provided with a plurality of joints. The members between the joints of each finger (sometimes called links)
A sensor for detecting a contact state with the object is provided. In the following, such a robot hand is referred to as an “articulated finger type robot hand”. In the proposed multi-joint finger type robot hand, the joint is moved so that the link of each finger contacts the target evenly while detecting the contact state with the target with a plurality of sensors provided on each finger. As a result, even objects having different shapes and sizes can be appropriately gripped.

JP 2009-166152 A

However, since the proposed multi-joint finger type robot hand has to control the movement of a plurality of joints provided for each finger based on information from a plurality of sensors provided for each finger, There is a problem that the control of the entire robot including the robot hand becomes very complicated. In addition, since the plurality of joints operate in parallel, the amount of processing for controlling the operation increases, and it is difficult to operate quickly. Furthermore, since a plurality of joints operate at the same time, a large amount of power is required at one time. As a result, there is a problem that a large capacity power source is required.

The present invention has been made in order to solve at least a part of the above-described problems of the prior art, and is an articulated finger type without impairing the feature that various objects can be appropriately gripped. It is an object of the present invention to provide a technique capable of operating a robot including a robot hand with simple control.

In order to solve at least a part of the problems described above, the robot driving apparatus of the present invention employs the following configuration. That is,
Driving a robot having a plurality of fingers provided opposite to each other, at least one finger having a plurality of joints, and performing an operation of gripping an object using the plurality of fingers A device,
By moving the plurality of joints in accordance with the object to be gripped, the shape of the finger portion having the plurality of joints is transformed into a gripping shape that is the shape when the object is gripped. Finger shape deforming means,
And a gripping operation means for gripping the object using the plurality of finger portions while maintaining the grip shape.

The robot driving method of the present invention corresponding to the robot driving device described above is
Driving a robot having a plurality of fingers provided opposite to each other, at least one finger having a plurality of joints, and performing an operation of gripping an object using the plurality of fingers A method,
By moving the plurality of joints in accordance with the object to be gripped, the shape of the finger portion having the plurality of joints is transformed into a gripping shape that is the shape when the object is gripped. A first step of
A second gripping the object using the plurality of fingers while holding the grip shape.
The gist is to provide a process.

In such a robot driving apparatus or driving method according to the present invention, prior to gripping a target object using a plurality of opposing finger portions, the shape of the finger portion having a plurality of joints is measured. Deforms to a gripping shape according to the object. Here, the grip shape is the shape of the finger when gripping an object. Therefore, the grip shape is different depending on the object to be gripped.
And the operation | movement which hold | grips a target object is performed using the several finger part provided facing, holding the shape of a finger part in a holding | grip shape.

By so doing, the shape of the finger part is deformed into a gripping shape corresponding to the object, so that the object can be appropriately gripped. In addition, since the object is held while the finger part is held in the holding shape, the object can be held by simple control as in the case of a robot having a so-called gripper type robot hand. Furthermore, even when the object to be grasped is changed, the shape of the finger portion only needs to be changed to a grasping shape corresponding to the new object, so that it is possible to respond flexibly and quickly. Of course, an appropriate gripping shape must be set in advance according to the object to be gripped, but since the robot often knows the shape of the object to be gripped, The object can be appropriately gripped by driving the robot in the manner described above. In particular, in the case of a robot used at a manufacturing site, since the shape of the object to be grasped is determined in advance, it is possible to appropriately grasp all the objects by driving by the method described above.

Further, in the robot driving apparatus or driving method of the present invention described above, the following may be performed. First, when deforming the finger part into a gripping shape prior to gripping the object,
The finger part on the tip side of one joint determined according to the object from the plurality of joints is deformed into a gripping shape. And you may make it hold | grip a target object with a several finger part by moving one joint defined according to the target object.

When the object to be grasped is small, there is a case where it is possible to appropriately grasp by grasping using a part on the tip side of the finger portion. Therefore, in such a case, after deforming the finger part on the distal end side relative to one joint determined according to the object into a gripping shape, by moving the one joint to grasp the object, Even a small object can be gripped appropriately.

Also, a plurality of fingers provided on the robot are erected from the base member, and among the plurality of fingers, a finger having at least a plurality of joints is attached to the base member by the joint. When the robot is driven, it may be driven as follows. First, prior to gripping an object, the entire finger portion provided with a plurality of joints is deformed into a gripping shape. Thereafter, the object may be grasped by moving the joint attached to the base member by the finger portion deformed to the grasping shape.

Since the reaction force from the target is applied to the finger when gripping the target, the joint that moves when gripping the target needs to generate a larger torque than the joint that simply holds the grip shape,
As a result, the size of the joint also increases and it is easy to win. And it is easier to provide a joint with a large size in the part where the finger part is attached to the base member, rather than providing it in the middle of the finger part.
Therefore, if a grip shape is formed by the entire finger part provided with a plurality of joints, and the finger part moves the joint attached to the base member to grip the object, a large torque is generated to firmly hold the object. And can be gripped.

Moreover, when driving a robot provided with a plurality of finger portions provided with a plurality of joints, it may be driven by the following method. First, prior to gripping an object, a plurality of finger portions provided with a plurality of joints are deformed into a gripping shape determined for each finger portion. Here, the plurality of finger portions provided with the plurality of joints may be provided so as to face each other, or may be provided side by side so as to face the other finger portions. Then, it is good also as holding a target object, keeping each finger part in a holding shape.

In this way, it can be deformed into different grip shapes for each finger part and grip the object,
Even if the shape of the object becomes complicated, it is possible to hold it appropriately.

The above-described robot drive device or drive method of the present invention can also be grasped in the form of a robot. The robot of the present invention grasped in this manner is
A robot having a plurality of fingers provided opposite to each other, at least one finger having a plurality of joints, and a robot that grips an object using the plurality of fingers.
By moving the plurality of joints in accordance with the object to be gripped, the shape of the finger portion having the plurality of joints is transformed into a gripping shape that is the shape when the object is gripped. Finger shape deforming means for causing;
A gripping operation means for gripping the object by the plurality of finger portions by bringing the plurality of finger portions provided facing each other while holding the grip shape. To do.

According to the robot of the present invention having such a configuration, prior to gripping an object using a plurality of fingers, the shape of a finger having a plurality of joints is changed to a grip shape corresponding to the object. Transforms into Thereafter, the object can be gripped by using the plurality of fingers by bringing the plurality of fingers provided facing each other while holding the shape of the fingers in the grip shape.

In such a robot, simply performing control for deforming the finger part into a gripping shape and control for gripping the target object while holding the gripping shape, the object can be simply Can be gripped by control. Further, even when the object to be gripped is changed, it is possible to flexibly and quickly cope with the change of the object only by changing the shape of the finger part to a gripping shape corresponding to the object.

It is explanatory drawing which shows the structure of the robot hand part mounted in the robot. It is explanatory drawing which showed the rough structure of the robot carrying the robot hand of a present Example. It is explanatory drawing which shows a mode that a big target object is hold | gripped with the drive method of the robot of a present Example. It is explanatory drawing which shows a mode that a small target object is hold | gripped with the drive method of the robot of a present Example. It is a flowchart which shows the holding | grip movement control process performed at the time of the drive of a robot. It is explanatory drawing which shows the grip shape data memorize | stored according to the target object. It is explanatory drawing which illustrated a mode that grip operation | movement and releasing operation | movement are performed changing a grip shape according to a target object. It is the time chart which showed a mode that each joint of a robot hand was driven when the drive method of a present Example was applied. It is the time chart which showed a mode that each joint was driven when the drive method of a general robot hand was applied. It is explanatory drawing which showed a mode that a small target object was hold | gripped using the drive method of a 1st modification. It is explanatory drawing which showed a mode that the target object was hold | gripped using the drive method of a 2nd modification. It is explanatory drawing which showed the drive method of the robot of the 3rd modification which hold | grips a target object using the robot hand provided with the finger part comprised from several links, and the fixed finger part which does not have a movable part. . It is explanatory drawing which illustrated the robot hand part of the robot of the 4th modification provided with several finger parts facing each other. It is explanatory drawing which illustrated the other aspect of the robot hand part of the robot of a 4th modification.

Hereinafter, in order to clarify the contents of the present invention described above, examples will be described in the following order.
A. Device configuration:
B. Grasping operation of the object of the present embodiment:
C. Control processing of the gripping operation of the present embodiment:
D. Variations:
D-1. First modification:
D-2. Second modification:
D-3. Third modification:
D-4. Fourth modification:

A. Device configuration :
FIG. 1 is an explanatory diagram showing a configuration of a robot hand 10 mounted on the robot of this embodiment. As shown in the drawing, the robot hand 10 of the present embodiment includes a palm portion 100 that is a substantially rectangular plate-shaped member, two finger portions 110 that are erected so as to face each other, and the like. It is configured. Each finger part 110 is configured by connecting a plurality of links by connecting a short bar-like member (referred to as a link in this specification) to another link by a joint. In the example shown in FIG. 1, three links are connected to form one finger 110. In the following, these links are connected to the first link 11 from the side closer to the palm 100.
2 and the second link 114 and the third link 116. The palm 100 and the first link 112 are connected by a first joint 112a, the first link 112 and the second link 114 are connected by a second joint 114a, and the second link 114 and the third link 116 are connected.
Are connected by a third joint 116a.

In the robot hand 10 illustrated in FIG. 1, the finger portions 110 facing each other have the same structure. For this reason, in order to avoid complication of illustration, only the one finger part 110 is displayed with the links and joints numbered. However, the fingers 110 facing each other are not necessarily limited to having the same structure. For example, the number of links and joints may differ between the fingers 110 provided facing each other,
The link size may be different. Further, the finger parts 110 standing from the palm part 100 are not necessarily provided with the same number of finger parts 110 facing each other. For example, one finger part is opposed to the two finger parts 110. 110 may be provided.

Each joint 112a, 114a, 116a incorporates an actuator (not shown) so that each joint 112a, 114a, 116a can be moved individually. For example, since the first joint 112a connects the palm part 100 and the first link 112, the first link 112 stands up with respect to the palm part 100 by driving an actuator built in the first joint 112a. The angle to be set can be changed. Second
Since the joint 114a connects the first link 112 and the second link 114, the second joint 1
The angle of the second link 114 with respect to the first link 112 can be changed by driving an actuator built in 14a. Similarly, the angle of the third link 116 with respect to the second link 114 can be changed by driving an actuator built in the third joint 116a.

In addition, the operation of the actuator built in each joint 112a, 114a, 116a is
It is controlled by the control unit 12 described later. Further, a pressure sensor 110 s is provided on the surface of the side of the plurality of links constituting the finger part 110 that is in contact with the object to be grasped (the side facing the other finger part 110). In the example shown in FIG. 1, a pressure sensor 110 s is provided on the surface of the second link 114. The link for providing the pressure sensor 110s is not necessarily the second link 114, and may be provided on another link. The output of the pressure sensor 110s is input to the control unit 12.

FIG. 2 shows a rough configuration of the robot 1 equipped with the robot hand 10 of the present embodiment. As shown in the figure, the robot body section 16 is provided with one robot arm 14 on each of the left and right sides, and the robot hand 10 of this embodiment is attached to the tip of the robot arm 14. In addition, a control unit 12 that controls the driving operation of the robot hand 10 and the robot arm 14 or the operation of the entire robot 1 is mounted inside the main body unit 16. The control unit 12 corresponds to the drive device of the present invention. The control unit 12 is configured such that a ROM and a RAM are connected to each other by a bus so that data can be exchanged with each other around a CPU. In FIG. 2, it is assumed that the control unit 12 is built in the main body 16 of the robot 1, but the control unit 12 is not necessarily built in the main body 16 and is installed separately from the robot 1. You may do it.

In general, in a robot hand (multi-joint finger type robot hand) provided with a plurality of joints on one finger as shown in FIG. 1, the shape of the finger can be changed by moving the plurality of joints. Even if the size and shape of the object to be grasped are changed, it is possible to appropriately grasp the object by appropriately operating the respective joints. However, on the other hand, the control target increases as the number of joints increases, so that the control for gripping the target object becomes complicated. Therefore, in the present embodiment, it is possible to effectively take advantage of the fact that a large number of joints are provided on the finger portion, and it is possible to appropriately grasp objects having different sizes and shapes, but the control for grasping becomes complicated. In order to avoid this, the object is held by the following method.

B. Grasping operation of the object in this embodiment:
FIG. 3 is an explanatory diagram showing a state in which a large object Wa is gripped using a driving method of a robot equipped with the robot hand 10 of the present embodiment. FIG. 3A shows a state before the gripping operation is started. In the state shown in the figure, no electric power is supplied to the actuator built in the joint of the finger part 110, and therefore, the two finger parts 110 of the robot hand 10 are in a state of hanging down due to gravity.

When gripping the object Wa below the robot hand 10 from this state, first, the shape of the finger part 110 is deformed by moving the joints 112a, 114a, 116a of the finger part 110. The shape for deforming the finger part 110 at this time is determined in advance according to the object Wa to be grasped, and in particular, the shape of the finger part 110 itself (the first link 1).
12, the shape formed by the second link 114 and the third link 116) is the finger 1
10 is set to a shape when the object Wa is gripped (hereinafter referred to as a gripping shape). FIG. 3B shows a state in which the two finger portions 110 are deformed into a grip shape corresponding to the object Wa.

Subsequently, the angles of the joints 112a, 114a, and 116a are maintained (thus, the finger portion 11
The robot hand 10 is moved closer to the object Wa by moving the robot arm 14 while keeping the shape of 0 in the gripping shape. Then, as shown in FIG. 3C, when the robot hand 10 is brought close to an appropriate position with respect to the object Wa, the first joint at the base of the finger part 110 is maintained with the finger part 110 kept in a gripping shape. Rotate only 112a. As a result, FIG.
As shown in d), the object Wa can be gripped by the two fingers 110.

According to such a gripping operation, as shown in FIG.
After deforming the shape of the finger part 110 according to the above, the object Wa can be gripped by moving only the first joint 112a at the base of the finger part 110. The operation of moving the first joint 112a to grip the object Wa is similar to the operation of a simple robot hand called a gripper gripping the object, and can be realized with extremely simple control. .

FIG. 4 is an explanatory view showing a state in which a small object Wb is gripped by using a driving method of a robot equipped with the robot hand 10 of the present embodiment. Similar to FIG. 3 described above, FIG.
FIG. 4B shows a state before entering the gripping operation, and FIG. 4B shows a state where the shape of the finger part 110 is changed to the gripping shape. FIG. 4C shows a state in which the robot hand 10 is brought close to the object Wb while the finger 110 is held in a gripping shape, and FIG.
) Shows a state where the object Wb is held.

As apparent from a comparison between FIG. 3D and FIG. 4D, if the size (or shape) of the object to be grasped is different, the shape of the finger 110 when the object is grasped. The (grip shape) is also different. For example, if a large object Wa is grasped, the object Wa can be appropriately grasped by deforming the finger part 110 into a shape that is held by all the links. On the other hand (see FIG. 3D), in the case of a small object Wb, by deforming the finger 110 into a shape sandwiched between the second link 114 and the third link 116, the object Wb. Can be properly gripped (see FIG. 4D).

Therefore, when gripping the small object Wb, first, when the gripping operation starts, the finger 1
The shape of 10 itself (the shape formed by the first link 112, the second link 114, and the third link 116) is deformed into a gripping shape corresponding to the object Wb (see FIG. 4B).
. Thereafter, the robot hand 10 is brought close to the object Wb while maintaining the grip shape (
3 (c)), the first joint 11 at the base of the finger 110 while keeping the finger 110 in a gripping shape.
The object Wb is gripped by rotating only 2a.

Even when gripping such a small object Wb, first, the shape of the finger part 110 is first deformed into a gripping shape corresponding to the object Wb, and thereafter, the first joint 112 at the base of the finger part 110 is used.
The object Wb can be gripped by moving only a. For this reason, the object Wb can be gripped by extremely simple control, like a simple robot hand called a so-called gripper.

Further, the shape of the finger part 110 itself is deformed in advance into a gripping shape corresponding to the object to be gripped. Moreover, since the finger part 110 is provided with many joints, it can be deformed into various grip shapes depending on the object. As a result, it is possible to appropriately hold a wide variety of objects having different sizes and shapes while being extremely simple control similar to that of the gripper. Hereinafter, the in-control processing for realizing such a gripping operation will be specifically described.

C. Control processing of gripping operation of this embodiment:
FIG. 5 is a flowchart showing a gripping motion control process executed to realize the gripping motion of the present embodiment. This process is a process performed by the CPU built in the control unit 12 executing a program stored in the ROM. When the gripping motion control process is started as shown in the drawing, first, information for specifying an object to be gripped is acquired (step S100). As described above with reference to FIGS. 3 and 4, in the gripping operation of the present embodiment, the finger 110 is deformed into a gripping shape corresponding to the target object to be gripped before actually gripping the target object. Therefore, the object to be grasped needs to be specified in advance. Therefore, when the gripping motion control process is started, first, information for specifying an object to be gripped from now is acquired.

Here, the information for specifying the object may be set by a human by operating the operation button of the control unit 12, or the IC chip or tag attached to the object or the identification code is controlled. It may be acquired by reading by the unit 12. Further, it may be acquired by reading an image of an object to be grasped from now. That is, the shape of an object that may be grasped is stored in advance in the ROM of the control unit 12, and an image of the object that is about to be grasped is read and matched with any of the objects stored in advance. The object may be specified by determining whether to do so. In many cases, the object to be gripped is determined in advance, and the direction in which the object is placed with respect to the robot hand 10 is also almost determined. Therefore, the object can be easily specified by such a method. it can.

When the information for specifying the object to be grasped is acquired, the grasping shape data of the finger part 110 corresponding to the object is read (step S102). The grip shape data is
It is stored in advance in the ROM of the control unit 12 in association with the object. FIG. 6 shows the control unit 12.
It is explanatory drawing which illustrated the grip shape data memorize | stored in. Here, the grip shape data is data indicating what angle should be set for each joint of the finger 110. FIG.
As shown in (a), the grip shape data is set for each object. Further, FIG. 6B shows the meaning of the angle set in the grip shape data. For example, the angle θ <b> 1 set for the first joint 112 a indicates an angle at which the first link 112 rises from the surface of the palm 100. Further, the angle θ <b> 2 set for the second joint 114 a indicates an angle at which the second link 114 is bent with respect to the first link 112. Furthermore, the angle θ3 set for the third joint 116a is the second link 11.
4 represents an angle at which the third link 116 is bent.

In step S102 of the gripping motion control process shown in FIG. 5, an object is identified based on the information acquired in step S100, and gripping shape data (respective joints 112a, 114a, 116a) set for the object. Are read from the ROM of the control unit 12. For example, if the object to be grasped is the object Wa, the first joint 112
The angle a is θ1a, the angle of the second joint 114a is θ2a, and the angle of the third joint 116a is θ3a.
Is read as grip shape data (see FIG. 6A).

Subsequently, the actuators built in each joint 112a, 114a, 116a are
By driving based on the grip shape data, the shape of the finger part 110 is transformed into a grip shape (step S104). As shown in FIG. 6A, in this embodiment, only one grip shape data is set according to the object. Therefore, all the finger parts 110 are deformed into the same gripping shape. However, gripping shape data may be set for each finger unit 110, and each finger unit 110 may be transformed into a different gripping shape. In this way, even when an object having a complicated shape is gripped, it can be gripped more appropriately.

When the shape of the finger part 110 is changed to the gripping shape in this way, thereafter, a gripping operation and a releasing operation set in advance are performed in the same manner as a simple robot hand called a gripper (step S106). That is, first, the robot hand 10 is moved to the target object, and then the base joint (first joint 112a) of the finger part 110 is moved to hold the target object with the two finger parts 110. At this time, the second joint 114a and the third joint 1
16a does not move, and therefore the shape of the finger 110 itself is kept in the grip shape. Further, the force for gripping the object is determined by the pressure sensor 110s provided on the second link 114 of the finger part 110.
Control based on the output of. Then, after moving the robot hand 10 to a predetermined position while holding the object, only the first joint 112a is moved (while the finger part 110 is maintained in the holding shape), and the finger part holding the object 110 is released. Thereafter, the robot hand 10 is moved to the original position.

Since the robot hand 10 cannot be left in a state where the object is held, the operation of releasing the held object is always performed after the operation of holding the object. . Therefore, in this specification, the operation of gripping the object and the operation of releasing the gripped object are collectively referred to as “grip release operation”.

When the grip release operation for one object is completed in this way, it is determined whether or not there is an object to be gripped (step S108). This determination can be made by various methods. For example, when the number of objects is known in advance, it can be determined based on whether or not the number of times of performing the grip release operation has reached the number of objects. Alternatively, an image of a position where an object to be grasped is placed and a determination is made based on whether the object exists at that position, or an IC chip is attached to the object, and the data of the IC chip is Judgment can also be made based on whether or not data can be read.

As a result, when it is determined that there is no object to be gripped (step S108: n
o) The gripping motion control process in FIG. On the other hand, when it is determined that there is an object to be gripped (step S108: yes), it is determined whether or not the object has the same shape as the object gripped last time (step S110). . This determination can also be made by various methods. For example, when the type, number, and order of objects to be grasped are predetermined as a schedule, the object to be grasped next has the same shape as the object grasped last time by referring to the schedule. It can be determined whether or not. Alternatively, the determination can be made by providing an IC chip, a tag, or the like on the object, and comparing the data read from the IC chip, the tag, etc. with the data of the object gripped last time. Furthermore, the image of the object may be read and the determination may be made based on the shape of the object.

As a result, when it is determined that the object to be gripped next has the same shape as the object gripped last time (step S110: yes), the predetermined shape is again maintained while keeping the shape of the finger 110 in the gripping shape. A grip release operation is performed (step S106). That is, the robot hand 10 is moved to the target, and only the base joint (first joint 112a) of the finger 110 is moved to grip the target. Then, after the robot hand 10 is moved to a predetermined position while holding the object, only the first joint 112a is moved to release the object being held, and then the robot hand 10 is returned to the original position again. Let Robot hand 1 after releasing the object
When returning 0 to the original position, the shape of the finger 110 may be maintained in the grip shape.

On the other hand, when it is determined that the object to be gripped next is not the same shape as the object gripped last time (step S110: no), the process returns to the top of the gripping motion control process, and the above-described series Execute the process. That is, the information for specifying the object to be grasped is acquired (
After reading new grip shape data according to the object (step S100) (step S100)
102), the finger part 110 is deformed according to the grip shape data (step S104).
As a result, the shape of the finger part 110 changes from a grip shape corresponding to the object gripped last time to a new grip shape. Thereafter, a predetermined grip release operation is performed while keeping the shape of the finger 110 in a new grip shape (step S106). In this grip release operation, as described above, the second joint 114a and the third joint 116a are not moved, but the first joint 112a (
Since only the joint at the base of the finger 110 is moved, the object can be grasped or released in exactly the same manner as a so-called gripper type robot hand.

When the grip release operation for the new object is thus completed, it is determined whether or not there is an object to be gripped (step S108), and the above-described series of processing is repeated until there is no object to be gripped. If it is determined that there is no object to be gripped (step S108: no), the gripping operation control process in FIG. 5 is terminated.

FIG. 7 is an explanatory diagram illustrating a state in which a grip release operation is performed on different objects by the above-described grip operation control process. When gripping a large object Wa, after the finger part 110 is deformed into the gripping shape shown in FIG. 7A, the operation of gripping or releasing the object Wa is repeated. Since the finger 110 is kept in the same gripping shape during the grip release operation, the grip release operation can be performed in the same manner as a so-called gripper type robot hand. Further, as long as the object to be grasped is the object Wa, there is no need to deform the finger part 110, so that in this respect as well, the grasping and releasing operation can be performed just like the gripper type robot hand.

On the other hand, when the object to be gripped is changed to a small object Wb, the finger 110 is deformed to the gripping shape shown in FIG. Also in this case, after the finger part 110 is deformed into the gripping shape, the finger part 1 is used unless the object to be gripped is changed.
There is no need to deform 10. For this reason, the gripping and releasing operation can be performed on the small target object Wb just like the gripper type robot hand.

As described above, according to the driving method of the robot on which the robot hand 10 of this embodiment is mounted, the shape of the finger part 110 is deformed in advance according to the object to be grasped, so that it looks as if it is a gripper type robot. The object can be gripped with simple control just like a robot equipped with a hand. Further, even when the object to be grasped is changed, the object can be grasped appropriately only by deforming the finger part 110 into a shape corresponding to the new object. As a result, although it is simple control like a robot equipped with a gripper type robot hand, it is possible to flexibly and quickly respond to a change of the object and appropriately hold the object.

Of course, in order to grip the object in this way, it is necessary to store grip shape data corresponding to the object in the memory (ROM or RAM) of the control unit 12 in advance. But,
Since the robot often knows in advance the shape of the object to be gripped, in most cases, grip shape data can be stored in advance. In addition, when the robot is used particularly at a manufacturing site, the objects to be grasped are determined in advance, and it is possible to obtain grasp shape data for these objects.

Furthermore, the driving method of the present embodiment described above is characterized in that the control operation and the drive operation of the robot equipped with the robot hand 10 are performed in a time-distributed manner. There is a big merit from the viewpoint of consumption. Hereinafter, this point will be described.

FIG. 8 is a time chart showing how the joints 112a, 114a, and 116a of the finger unit 110 are driven by the driving method of the robot equipped with the robot hand 10 of the present embodiment. In the upper part of the figure, the operating state of the robot hand portion (robot hand 10) is shown, and below the joints 112a, 114a, 116a provided on the finger 110.
The operating state of is shown. Also, in the margin below the figure, for reference, the robot hand 1
The correspondence relationship between the operation state of 0 and each state shown in FIG. 3 or FIG. 4 is shown.

As described above, in the driving method of the robot equipped with the robot hand 10 of the present embodiment, when gripping a new object, first, the shape of the finger part 110 is changed to a gripping shape corresponding to the object. Deform. Therefore, as shown in FIG. 8, the first joint 112a, the second joint 114a,
The third joint 116a is driven. As described above with reference to FIG. 5, since this operation only moves each joint to a predetermined angle, the control load of the control unit 12 is very small. In addition, since all of the first link 112, the second link 114, and the third link 116 are idling without receiving a reaction force from the object, power consumption is also small. In FIG. 8, the driving of each joint at the time of forming the gripping shape is indicated by a broken-line rectangle, which is a driving with less burden on both the control load and the power consumption. It represents that.

After the shape of the finger part 110 is changed to the gripping shape, the robot hand 10 is moved to the target object while keeping the finger part 110 in the gripping shape. During this time, each joint consumes only the power that maintains the current angle. Moreover, since neither joint is moved, the control load of the control part 12 is very small. In particular, as an actuator for moving each joint, if an actuator having a characteristic of maintaining the current state is employed unless operated, such as a so-called ultrasonic piezo motor, the finger 110 is maintained in a gripping shape. Therefore, it is possible to prevent generation of control load and power consumption.

When the robot hand 10 is moved to the target object, the first joint 112 is now moved.
The movement of gripping the object is started by driving a (the joint at the base of the finger part 110). At this stage, since the first link 112, the second link 114, and the third link 116 receive a reaction force from the object, a certain amount of power is consumed with the driving of the first joint 112a.
Further, the pressure sensor 1 provided on a part of the finger 110 (second link 114 in this embodiment).
While detecting the output of 10 s, the movement of the first joint 112a must be controlled so that the object is gripped with an appropriate force, so that a suitable control load is generated in the control unit 12 as well. On the other hand, since it is not necessary to move the second joint 114a or the third joint 116a even after the start of gripping, only the power for maintaining the current angle is consumed, and the control load on the control unit 12 is not applied.

That is, in the driving method of the robot equipped with the robot hand 10 of the present embodiment, the control load or power consumption of the control unit 12 increases because the robot hand 10 is moved to the target object and then actually This is the period after the start of gripping an object. However, since the finger part 110 has already been deformed into a gripping shape at a stage prior to the start of gripping of the object, the second joint 114a and the third joint 116a at the stage of actually starting gripping the object. There is no need to move. As a result, it is possible to suppress an increase in control load and power consumption in the control unit 12. Such a merit becomes more remarkable when compared with a driving method of a robot equipped with a conventional general articulated finger type robot hand.

FIG. 9 is a time chart showing the movement of each joint 112a, 114a, 116a when the object is gripped by the same driving method as that of a robot equipped with a conventional general articulated finger type robot hand. In the conventional general robot driving method, after the robot hand 10 is moved to the target, all the joints are moved to start gripping the target. At this time,
In the conventional general driving method, the movement of each joint is controlled so that the reaction forces received by all the links are almost equal while detecting the reaction forces received by each link from the object. For this reason, not only the number of joints to be controlled simultaneously increases, but also the movement of one joint affects the movement of other joints, so the control load of the control unit 12 becomes very large. As a result, it is difficult to quickly perform the gripping operation.

In addition, since all the joints must be driven in a state of receiving a reaction force from the object, the power consumption required for driving each joint also increases. As shown in FIG. 9, since all the joints must be moved simultaneously, the power consumption of the robot hand 10 as a whole becomes very large, and the power consumption of the robot as a whole is correspondingly increased. It gets bigger. On the other hand, in the driving method of the robot equipped with the robot hand 10 of the present embodiment shown in FIG. 8, at the stage where the control load and power consumption are the largest (the stage where the object is gripped), the first joint 112a is moved, and the second joint 114a and the third joint 116a are moved.
Therefore, the control load of the control unit 12 and power consumption are not concentrated. As a result, it is possible to quickly perform a gripping operation without being restricted in terms of control processing speed and power consumption. Also, a relatively small power source can be adopted as a power source for driving the entire robot including the robot hand 10.

As shown in FIG. 8, in the above-described embodiment, the robot hand 10 is moved to the target after the shape of the finger part 110 is changed to the gripping shape. But,
While the robot hand 10 is moved to the place of the object, the shape of the finger part 110 may be transformed into a gripping shape. As described above, the operation of deforming the finger part 110 into the gripping shape can be easily performed while moving the robot hand 10 because the control load and the power consumption are small. Therefore, the robot hand 10 can be quickly operated without increasing the control load and power consumption.

D. Modified example:
There are various modified examples of the driving method of the robot on which the robot hand 10 of this embodiment described above is mounted. Hereinafter, these modified examples will be briefly described.

D-1. First modification:
In the above-described embodiment, the grip shape is formed using all the links (the first link 112, the second link 114, and the third link 116) constituting the finger part 110, and the base joint (
It has been described that the object is gripped by moving the first joint 112a). However, the joint that moves when grasping the object is not necessarily the joint at the base of the finger 110 (the first joint 11).
It is not limited to 2a). In other words, a gripping shape may be formed by moving a joint provided in the middle of the finger part 110 to grip the object and using a link on the tip side of the joint.

FIG. 10 is an explanatory diagram showing how a small object Wb is gripped using the driving method of the first modification. As described above with reference to FIG. 4, the small object Wb is the second of the two finger portions 110.
It can be gripped by being sandwiched between the link 114 and the third link 116. there,
In forming the grip shape at the second link 114 and the third link 116, first, the shape of the finger part 110 is deformed into a shape as shown in FIG. Next, the robot hand 10 is moved to the place of the object Wb as shown in FIG. 10C while keeping the shape of the deformed finger part 110. In this state, the object Wb can be appropriately gripped by moving only the second joint 114a while maintaining the grip shape formed by the second link 114 and the third link 116.

Even in the driving method of the first modified example, when the object Wb is actually gripped, the second joint 1
It is only necessary to move 14a, and other joints need only be held. For this reason, it is possible to grip an object with extremely simple control like a robot equipped with a so-called gripper type robot hand. Further, the control load and power consumption of the control unit 12 are not concentrated.

D-2. Second modification:
In the above-described embodiment or modification, it has been described that the finger part 110 is attached to the palm part 100 by a joint. Therefore, the finger part 110 can only move so as to swing in the front-rear direction around the attachment position with respect to the palm part 100. However, the present invention is not limited to the case where the finger unit 110 is attached to a position where the palm unit 100 is fixed, but to a robot equipped with a robot hand configured such that the attachment position of the finger unit 110 moves in the front-rear direction. A driving method can be applied.

FIG. 11 is an explanatory diagram showing a state in which the object Wa is gripped using the driving method of the second modified example. In the robot hand 20 shown in FIG. 11, two finger parts 110 are attached to the palm part 200, and the attachment positions of the respective finger parts 110 are movable in the front-rear direction. Even when the object Wa is gripped using such a robot hand 20, first, the shape of the finger part 110 is deformed into a gripping shape corresponding to the object Wa. And robot hand 2
After moving 0 to the place of the object Wa, the attachment position of each finger part 110 is advanced while keeping the grip shape. In FIG.11 (b), keeping the shape of the finger part 110 in a holding | grip shape,
The manner of advancing the mounting position is shown. In this way, as shown in FIG.
The object Wa can be gripped.

Also in the driving method of the second modified example, since the object Wa is grasped after the finger part 110 is deformed in advance to the grasping shape, when the object Wa is actually grasped, the attachment position of the finger part 110 is determined. Just move it. For this reason, it is possible to grip an object with extremely simple control like a robot equipped with a so-called gripper type robot hand. Also, the control unit 12
The control load and power consumption are not concentrated. In addition, the finger 11 depending on the object
By transforming 0 into an appropriate gripping shape, it is possible to respond flexibly and quickly even when the object to be gripped is changed.

D-3. Third modification:
In the above-described embodiment or modification, the finger portions 110 provided to face each other have been described as the finger portions 110 having the same shape. However, the opposing finger parts 110 do not necessarily have to have the same shape, and for example, the number and size of links may be different. Further, the one finger part may be a fixed finger part having no movable part. The driving method of the present invention can also be applied to a robot equipped with a robot hand having such a finger part.

FIG. 12 is an explanatory diagram showing a state in which an object is gripped using a robot provided with a finger part 310 composed of a plurality of links and a fixed finger part 320 having no movable part. FIG.
2 (a) shows a robot hand portion (robot hand 30) before the gripping operation is started. As shown, the finger 310 includes a first joint 312a and a second joint 3.
Four joints 14a, a third joint 316a, and a fourth joint 318a are provided. A fixed finger 320 is erected from the palm 300 at a position facing the finger 310.

Even when a target is gripped using a robot equipped with such a robot hand 30, first, the shape of the finger part 310 is changed to a gripping shape corresponding to the target. For example, if a large object Wa is gripped, it is deformed into a gripping shape as illustrated in FIG. On the other hand, if a small object Wb is to be gripped, it is deformed into a gripping shape as illustrated in FIG. Then, after moving the robot hand 30 to the target, the finger unit 310 is moved.
The finger part 310 and the finger part 320 are moved by moving only the joint (first joint 312a)
Grab the object in between. FIG. 12 (c) shows a state where a large object Wa is gripped, and FIG. 12 (e) shows a state where a small object Wb is gripped.

As described above, even when the finger parts provided opposite to each other have different shapes or different structures, various shapes of objects can be obtained by changing the shape of the finger parts into gripping shapes corresponding to the objects. It becomes possible to grip appropriately. In addition, since the operation of actually gripping the object is the same as that of a so-called gripper type robot hand, it can be realized by simple control.

D-4. Fourth modification:
In the above-described embodiment or modification, it has been described that one finger part 110 is provided to face each other. However, since the driving method of the present invention is characterized by light control load and low power consumption, a hand portion (robot hand) provided with a plurality of fingers facing each other is mounted. It can be said that it is particularly excellent as a robot driving method.

FIG. 13 is an explanatory view exemplifying a robot hand portion (robot hand 40) according to a fourth modified example in which a plurality of finger portions 110 are provided to face each other. In the illustrated hand portion (robot hand 40) of the fourth modified example, four finger portions 110 are provided in a horizontal line in the same direction so as to face these four finger portions 110. Similarly, four fingers 1
10 are provided in a horizontal row. The configuration of each finger unit 110 is the same as the configuration of the finger unit 110 of the present embodiment described above, and a description thereof will be omitted. In addition, here, it is assumed that four finger portions 110 are provided to face each other, but the finger portions 11 provided to face each other.
The number of 0 does not necessarily have to be the same. For example, four fingers 110 may be provided on one side and three fingers 110 may be provided on the opposite side.

The robot hand portion (robot hand 40) of the fourth modified example illustrated in FIG.
Since three joints are provided for each of the finger parts 110, if all of these joints are moved simultaneously to try to grip an object, the control load and power consumption become very large. However, if the driving method of the present invention is applied, such a robot hand 4
Even a robot equipped with 0 can be driven appropriately while suppressing control load and power consumption. Hereinafter, an operation of gripping an object using the robot hand 40 will be described with reference to FIG.

Even when an object is gripped using a robot equipped with the robot hand 40 of the fourth modification, first, the shape of the finger part 110 is deformed to a gripping shape corresponding to the object to be gripped ( (Refer FIG.3 (b)). Here, since the hand part (robot hand 40) of the robot of the fourth modified example is provided with a total of eight finger parts 110, individual grip shape data is stored for each of these finger parts 110. In addition, each finger part 110 can be transformed into an individual grip shape. Then, after moving the robot hand 40 to the place of the object (FIG. 3C)
(See FIG. 3D.) The object is gripped by moving the base joint (first joint 112a) of each finger 110 while keeping each finger 110 in a gripping shape (see FIG. 3D).

If the object is grasped by such a method, the operation of deforming the plurality of finger parts 110 into the grasping shape and the operation of grasping the object can be performed at different timings. For this reason, even if the number of the finger parts 110 increases (eight in the example shown in FIG. 13), the control load and power consumption do not concentrate. In addition, the operation of deforming each finger part 110 into a gripping shape is merely a simple control that moves each joint to a predetermined angle, so even if the number of joints increases, a large control load is required. Never become. Furthermore, since the finger part 110 does not receive the reaction force from a target object in that case, power consumption does not increase.
In addition, when actually grasping an object, it is not necessary to move other than the joints (first joints 112a) at the bases of the respective finger portions 110, so that the control load and power consumption can be suppressed accordingly. it can. As a result, even a robot equipped with a robot hand 40 having a large number of fingers 110 can appropriately hold various objects with little increase in control load and power consumption.

Further, in the robot hand 40 in which a plurality of finger portions 110 are provided so as to face each other as described above, even if the object is a complicated shape by deforming each finger portion 110 into an appropriate gripping shape. It becomes possible to grip appropriately. For example, as illustrated in FIG. 13, the gripping shape of each finger part 110 is set to the finger part 1 provided at the center of the finger part 110 provided at both ends.
If the gripping shape is set so that the object 10 grips a larger object, the spherical object can be appropriately gripped. Or, conversely, if the finger part 110 provided at both ends is set to a gripping shape that holds a larger object than the finger part 110 provided in the center, the drum-shaped object is properly gripped. It becomes possible.

Further, in the robot hand 40 provided with a plurality of finger portions 110 facing each other as described above, each finger portion 110 is not moved when gripping an object, but each finger portion 110 is moved. You may make it move collectively. That is, as illustrated in FIG.
A pair of large links (base links 511) serving as the bases of 10 are attached to the palm part 100 so as to face each other, and a plurality of finger parts 110 are provided on each base link 511.
You may make it attach.

In the robot hand 50 having such a configuration, the fingers 110 are deformed into a holding shape by moving each joint of the fingers 110 before holding the object, and then the object is actually held. In doing so, the joints of the finger portions 110 may not be moved, but only the base joints of the base links 511 may be moved to grip the object. In this way, it is not necessary to move each finger part 110 separately when gripping the object, so that control for gripping the object can be simplified.

Although the robot driving method of this embodiment has been described above, the present invention is not limited to all the embodiments and modifications described above, and can be implemented in various modes without departing from the scope of the invention. is there.

DESCRIPTION OF SYMBOLS 1 ... Robot, 10 ... Robot hand, 12 ... Control part,
14 ... Robot arm, 20 ... Robot hand, 30 ... Robot hand,
40 ... Robot hand, 50 ... Robot hand, 100 ... Palm part,
110 ... finger, 110s ... pressure sensor, 112 ... first link,
112a ... 1st joint, 114 ... 2nd link, 114a ... 2nd joint,
116 ... 3rd link, 116a ... 3rd joint, 200 ... Palm part,
300 ... Palm part, 310 ... Finger part, 312a ... First joint,
314a ... second joint, 316a ... third joint, 318a ... fourth joint,
320 ... finger part, 511 ... foundation link, Wa ... object,
Wb ... Object

Claims (10)

  A first finger portion having a plurality of joints and rotatable;
  A second finger,
  A base provided with the first finger and the second finger,
  Before grasping the object, a joint provided on the opposite side of the base from one of the plurality of joints is rotated based on an angle predetermined according to the shape of the object. A moving robot hand.   The robot hand according to claim 1,
  The first finger part is rotatably provided by a base joint that is a joint provided in the base part,
  A robot hand for gripping the object by rotating the joint of the first finger to the angle and rotating the base joint.   The robot hand according to claim 1 or 2,
  The second finger unit is a robot hand having a plurality of joints.   The robot hand according to claim 3,
  A robot hand that rotates the plurality of joints of the second finger unit based on an angle determined in advance according to the shape of an object.   The robot hand according to claim 1, wherein
  The first finger unit is a robot hand having a force detector.   Arm,
  A first finger portion having a plurality of joints and rotatable;
  A second finger,
  A base provided with the first finger and the second finger,
  The first finger has a plurality of joints;
  Before grasping the object, a joint provided on the opposite side of the base from one of the plurality of joints is rotated based on an angle predetermined according to the shape of the object. A moving robot.   The robot according to claim 6,
  The first finger part is rotatably provided by a base joint that is a joint provided in the base part,
  A robot that grips the object by rotating the joint of the first finger to the angle and rotating the base joint.   The robot according to claim 6 or 7, wherein
  The second finger unit is a robot having a plurality of joints.   The robot according to claim 8, wherein
  A robot that rotates the plurality of joints of the second finger portion based on an angle determined in advance according to the shape of the object.   The robot according to claim 6, wherein
  The first finger unit is a robot having a force detector.

Images