JP3170903B2 - Robot hand - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a space robot arm or the like, which grips an object, performs minute positioning of the object, attaches and detaches the object to a predetermined place, and is attached to various devices. The present invention relates to a multifunctional robot hand that performs various operations such as performing a predetermined operation by operating a lever or a switch with a single robot hand.

[0002]

2. Description of the Related Art FIG.
It is an explanatory view showing a general situation in which the robot hand shown in Vol. 2, PP12 to 19 is used.
Denotes a robot hand, and 43 denotes a robot arm for positioning the robot hand 44 at a work position. Also,
FIG. 22 shows, for example, the Robotics Society of Japan, Vol. 7, No. 5, P1
FIG. 16 is a configuration diagram showing the conventional robot hand shown in FIG. 16, in which 2 is an actuator, 7 is a finger, 39 is a drive mechanism for transmitting the power of the actuator 2 to the finger 7,
0 indicates two types of movement of the finger 7 generated by the power of the actuator 2. FIG. 23 shows, for example, the Robotics Society of Japan, Vol. FIG. 8 is a configuration diagram showing another conventional robot hand shown in FIGS.
1 is a hand body, 7 is a finger, 5 is a joint provided in the middle of the finger,
Reference numeral 42 denotes a wire rope (not shown) for transmitting the power of the actuator to the joint 5 of the finger 7, and reference numeral 41 denotes a flexible tube through which the wire rope passes.

Next, the operation will be described. Usually, FIG.
As shown in FIG.
Work attached to the tip of 3. In the configuration of FIG. 22, the robot hand is attached to the tip of the robot arm as in the configuration shown in FIG. 21, and starts operation of the robot hand after moving to the position of the object to be gripped by controlling the robot arm. Then, first, actuator 2
Is driven, the power is converted into the opening and closing movement of the finger 7 by the transmission mechanism 39, and the finger 7 closes to grip the object. Also,
When the position of the robot hand 44 is deviated from the position of the object, or when giving a motion to the grasped object, the actuator 2 is driven to rotate the finger 7.

In the configuration shown in FIG. 23, similarly to the configuration shown in FIG. 21, the robot hand is attached to the tip of the robot arm, and controls the robot arm to move to an object position to be gripped. Next, when an actuator (not shown) is driven, the power of the actuator is changed to a driving wire rope 4 passing through a power transmission coil 41.
2 to the joint 5. Thereby, the joint 5 rotates and the finger 7 bends to grasp the object. Also,
The position and orientation of the object are changed by controlling the angles of the plurality of joints 5 in a coordinated manner while holding the object.

[0005]

Since the conventional robot hand is configured as described above, in the conventional example shown in FIG. 21, when the object is gripped, the object can only be rotated around one axis. It is impossible to perform minute positioning, which is important when inserting an object into a hole. For this reason, minute positioning is performed using an arm to which a robot hand is attached, but the arm is originally intended for rough positioning, and in order to perform accurate positioning simultaneously with rough positioning, the structure of the arm is required. In addition, there is a problem that the control device becomes complicated and the price increases.

In addition, since the motion that can be generated by the robot hand alone is limited, it is not possible to sufficiently absorb the impact force generated by an unexpected collision, and to sufficiently check that no collision occurs during operation. After that, there is a problem that the operation speed must be reduced so as not to be damaged even if a collision occurs.

Further, since only two fingers are opened and closed, there is a problem that the holding property of the gripped object is poor, and the position and posture of the gripped object with respect to the hand body are easily changed by an external force.

Further, in the conventional example shown in FIG. 22, it is possible to hold the object with the robot hand alone and to give an operation with six degrees of freedom. However, since there are many degrees of freedom, the structure becomes very complicated, and the control becomes difficult. Also in the device, there is a problem that a computer having a high calculation capability is required to control the degree of freedom, and the operation time is long.

The present invention has been made in order to solve the above-mentioned problems, and has a simple structure, but can finely position a gripped object, and can generate the same when a large gripping force is required. It is another object of the present invention to provide a robot hand which can reduce the impact force without releasing a grasped object even if an unexpected collision occurs, thereby preventing damage to the robot hand and a device to which the robot hand is attached.

It is another object of the present invention to provide a robot hand capable of smoothly performing a movement for fine positioning of an object when the object is gripped by surrounding the object with a plurality of links.

Further, even if weak force to grip an object body, for example, to a strong axial force to the rod-shaped object having a flange at each end, a robot hand that can pull out or push easily another device object The purpose is to gain.

Further, an object of the present invention to provide a robot hand that can stably grip the different objects of of the atmosphere.

Further, to increase the stability of the function of the robot hand to grip the object, a robot hand and an object thereof is to make given the smooth motion to the object.

[0014]

A robot hand according to the present invention comprises a plurality of fingers having a plurality of links connected by joints. Each joint generates a rotational force around a rotation axis. A spring is attached. The finger is attached to the actuator via a drive shaft and driven, and a first link is rotatably attached to a center portion of the first link by a rotary joint. The second link is arranged on the gripping object side. That is, a link that branches into two or more links from the middle of the finger is used, and a link that is close to another finger in the branch (second link)
Attached a spring so as to rotate around a joint provided on a link (first link) far from the other finger.

The side of the second link that grips the object is an arcuate curved surface, and the object is brought into contact with the curved surface to grip the object.

Further, when the object is sandwiched and gripped by changing the thickness of each finger, the position of the end of the finger in the direction along the object is equal on both sides of the object.

Also , the three fingers are mounted so as to rotate about parallel axes, and are provided close to each other with an interval that allows them to slip through each other when the three fingers are rotated, and are positioned inside. The tip of the finger to be used is made thinner, the other two fingers are made thicker, and the portion of the gripping surface close to the middle finger is chamfered.

Further, by increasing the friction coefficient of the other fingers and the surface facing the tip portion of the farthest link from Ha command body,
Conversely, the coefficient of friction in the region of each finger facing the other finger other than the above region is reduced .

[0019]

In the robot hand the present invention, when controlling the actuator to grip the object and close the fingers, contact fingers and the object. When the finger is further closed, the finger receives force from the object, and the joint in the middle of the finger opens. Since a spring is attached to the joint so as to generate a rotational force acting in the direction in which the finger closes, a force for gripping the object is generated by the spring, and as the joint opens, the gripping force by the spring increases. Since the gripping force is generated in this manner, by changing the posture of the finger with respect to the hand main body by the actuator, even if the gripping force is not particularly controlled, the stable gripping force is maintained by the spring force. The position of the object can be moved. In addition, when an object collides with another device while gripping the object and an impact force is applied, or when a finger collides with another device and an impact force is applied when moving the robot hand to a work position, By adjusting the opening angle of the finger with the actuator according to the impact force, it is possible to generate a motion that absorbs the impact force on the object while giving the grip force to the object, and damage the robot arm and other devices. Can be prevented. Further, when the second link rotates to the same position as the first link, the first link directly contacts the object and directly applies the power of the actuator to the object as the gripping force, so that a large gripping force can be easily obtained. Can occur.

In the second link, the surface for gripping the object is an arc or a curved surface close to a circular arc, so that the object is gripped by surrounding four or more links, and the angle of the link is controlled by an actuator. When an object is pushed in a direction away from the hand body, the difference between the direction of the force applied to the object and the direction in which the object is desired to move is reduced, and the movement can be given smoothly.

Further, each finger, for example if the gripping across the object having a flange from the left and right vertical portions to the flange, by the equal the thickness of a finger in the right and left of the object, on both sides of the object The finger is simultaneously in contact with the flange so that an equal force is applied, so that an axial force can be stably applied to the object.

In addition , since the fingers are partially chamfered by changing the thickness of the tips while maintaining the state in which they can pass each other when rotated, when the object is gripped so as to be sandwiched between the tips of the fingers, the size of the object is reduced. The contact position between the thick finger and the object changes even when the object changes, thereby realizing a situation where the three fingers and the object are stably in contact with each other. In addition, when the object is gripped so that the object is sandwiched between the three fingers, even small objects can be gripped without any problem because their fingertips can pass through each other.

Further, the coefficient of friction at the tip of the finger is increased .
If the object is held between the tip of the finger, the object and the finger come into contact with each other at the part with a high coefficient of friction, and even if an external force is applied to the object, the positional relationship between the object and the finger is not easily broken and stable gripping so it is obtained. Also, when an object is gripped by surrounding it with four or more links, the gripping is originally stable because the object is gripped so as to surround the object. By suppressing the frictional force, when the angle of the finger is changed by the actuator, slipping easily occurs between the object and the finger, so that the object can be given a smooth motion .

[0024]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG.
Is a configuration diagram of the robot hand according to the first embodiment , FIG. 2 is an explanatory diagram showing a state in which the robot hand grips an object by pinching the tip of a finger, and FIG. 3 is a diagram illustrating the robot hand surrounding the object with six links. Explanatory diagram showing a state where it is grasped,
FIGS. 4 and 5 show the results obtained by computer simulation in which the robot hand grips an object with the tip of a finger and gives motion to the object. FIG. 4 and FIG. 5 show a plane viewed from a direction perpendicular to the rotation axis of the finger. The explanatory diagrams shown in FIGS. 6 and 7 show the results obtained by computer simulation of how the robot hand grips the object with six links and gives motion to the object. It is explanatory drawing which showed the plane seen from the direction.

In FIG. 1, 1 is a hand body, 2 is an actuator fixed to the hand body to give a motion to a finger,
3 is a link driven by the actuator, 4 is a drive shaft for transmitting the movement of the actuator 2 to the link 3, 5 is a joint, 6 is another link connected to the link 3 by the joint 5, 7 is a link 3 and a joint 5 And a finger composed of a link 6, a compression spring 8 for applying a rotational torque to the link 6, 9
Is a stopper that limits the joint 5 from closing too much. 2 and 3, reference numeral 10 denotes an object to be gripped,
The other components that are the same as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description thereof will be omitted. 4, 5, 6, and 7, 11, 14, 17, and 20 indicate directions of motion given to the link 3 in order to operate an actuator (not shown) to give motion to an object.
Reference numerals 12, 15, 18, and 21 denote directions in which the joint 5 rotates with the movement of the link 3 and the link 6 moves as a result.
Reference numerals 3, 16, 19, and 22 denote the motions imparted to the object by the motions of the links 3 and 6, and the same components as those shown in FIG. The description of the operation will be omitted. Here, the suffix A of each numerical value indicates a state before applying motion to the object, and the suffix B of each numerical value indicates a state after applying motion to the object.

Next, the operation will be described. First, a case where the object 10 is gripped so as to sandwich the object 10 at the tip of the link 6 as shown in FIG. 2 will be described. First, the link 3 is opened by operating the actuator 2. At this time, the link 6 is also opened at the same time. Thereafter, similarly to the conventional example, the robot hand to which the robot hand is attached is controlled to move the robot hand to the object position. After the movement, when the link 3 is closed by operating the actuator 2, the link 6 is also closed while the joint 5 is fixed at first. However, the link 6 comes into contact with the object 10, and the link 6 exerts a force from the object 10. Then, it starts to rotate around joint 5. Hand body 1 by robot arm
The link 3 is further closed while the position is adjusted, and in FIG. 2, the gripping is completed when the gripping force generated by the spring 8 held inside the link 3 reaches a predetermined magnitude.

Next, as shown in FIG. 3, a case where the object is gripped so as to surround the object with four links will be described. Until the link 3 is moved to the work position, the actuator 2 is operated and the link 3 is closed, and the link 6 starts to rotate by receiving a force from the object 10, the tip of the link 6 holds the object 10 so as to sandwich it. Is the same. When the link 3 is further closed while the position of the hand main body 1 is adjusted by the robot arm, the object 10 comes into contact with the link 3 and the link 6 simultaneously. Since there are three fingers, the link and the object 10 are in contact at a total of six places. Further, when the link 3 is closed and in FIG. 3 the gripping force generated by the spring 8 set inside the link 3 reaches a predetermined magnitude, the gripping is completed.

Next, a method of moving the object 10 in the direction of the arrow 13 while holding the object 10 between the links 6 as shown in FIG. 4 will be described. In the initial state, the force generated by the spring 8 in the link 3 and the force received by the link 6 from the object 10 are in a stable state in the figure. From this state, the left and right links 3 are rotated in the direction of the arrow 11 by operating an actuator (not shown). This movement of the link 3 causes the link 6 to move away from the object 10, but in the figure, the joint 5 is closed by the force generated by the spring 8 held inside the link 3, and the link 6 moves in the direction of the arrow 12. It rotates, and is stabilized in a state where the force generated by the spring 8 and the force received by the link 6 from the object 10 are balanced again. As a result of the continuous movement of the link 3 and the link 6, the gripped object 10 moves in the direction of the arrow 13. When the link 3 is rotated in the direction opposite to the arrow 11 by the actuator 2, the link 6 rotates in the direction opposite to the arrow 12 with the movement of the link 3, and as a result, the object 10 is moved in the direction opposite to the arrow 13. Exercise. However, during the movement shown here, the angle formed between the tip of the link 6 and the surface of the object 10 slightly changes, but is absorbed by a method such as performing processing to change the unevenness at the tip of the link 6.

Next, a method of moving the object 10 in the direction of the arrow 16 while holding the object 10 between the links 6 as shown in FIG. 5 will be described. Object 10 in the initial state
Are balanced in the same manner as in the case where is moved in the direction of arrow 13, and the state is stable. When the left and right links 3 are rotated in the direction of arrow 14 by operating an actuator not shown in the figure, the left link 6
Tries to move away from the object 10, and the link 6 on the right side of the object 10 tries to push the object 10. As a result,
The object 10 moves in the direction of the arrow 16, and the left and right links 6 rotate slightly around the joint 5, and in the figure, the force generated by the spring 8 set inside the link 3 and the object 10
The force received by the link 6 is balanced and stabilized. By performing these operations continuously, a continuous movement in the direction of arrow 16 is realized. When the link 3 is rotated in the direction opposite to the arrow 14 by the actuator 2, the link 6 rotates in the direction opposite to the arrow 15 with the movement of the link 3, and the object 10 also moves in the direction opposite to the arrow 16. I do. However, during the movement shown here, the angle formed between the tip of the link 6 and the surface of the object 10 slightly changes, but is absorbed by a method such as performing processing to change the unevenness at the tip of the link 6.

Next, as shown in FIG. 6, while holding the object 10 so as to be surrounded by four links, the object 10 is
A method for moving the object in the direction of is shown. In the initial state, the forces are balanced and stable as in the case described above. When an actuator (not shown) is operated to rotate the left and right links 3 in the direction of arrow 17, the links 3 push the object 10, and the left and right links 3 similarly move the object 1
To press 0, the object 10 moves in the direction of arrow 19. At this time, since the force of the object 10 pushing the link 6 increases, the joint 5 rotates so that the force generated by the spring 8 held in the link 3 and the force of the object 10 pushing the link 6 are balanced in the figure. The link 6 rotates as indicated by the arrow 18. By continuously performing this movement, the movement of the object 10 in the direction of the arrow 19 is realized. When the link 3 is rotated in the direction opposite to the arrow 17 by the actuator, the link 6 rotates in the direction opposite to the arrow 18 with the movement of the link 3 and the object 10 moves in the direction opposite to the arrow 19. I do.

Next, as shown in FIG. 7, while holding the object 10 so as to be surrounded by four links, the object 10 is
A method for moving the object in the direction of is shown. In the initial state, the forces are balanced and stable as in the case described above. When an actuator (not shown) is operated to rotate the left and right links 3 in the direction of arrow 20, the left link 3 pushes the object 10 against the object 10 in FIG. Tries to move away from the object 10.
As a result, the object 10 moves in the direction of the arrow 22. At this time,
The left and right links 6 rotate as shown by the arrow 21 so that the force received from the object 10 and the force of the spring 8 held in the link 3 in the figure are balanced. By continuously performing this movement, the movement of the object 10 in the direction of the arrow 22 is realized. Also, the link 3 is moved by the actuator to
When the link 6 rotates in the opposite direction, the link 6 rotates in the direction opposite to the arrow 21 with the movement of the link 3 and the object 1
0 moves in the direction opposite to arrow 22.

In the description of FIG. 4, FIG. 5, FIG. 6, and FIG. 7, the method of realizing the movement in the directions of the respective arrows is shown, but the movement of FIG. 4 and FIG. 5, and FIG. By the combination, the movement of the finger 7 in an arbitrary direction in a plane perpendicular to the drive shaft 4 can be realized. Further, since the motion shown here is given to the object 10, if the external force applied to the object 10 is detected and the object 10 is controlled to move in a direction in which the external force is reduced, the impact of the robot hand alone can be obtained. It can have a power absorption function. In the above-described embodiment, the case where the three fingers rotate around two axes to perform minute positioning in the plane has been described. However, the three fingers rotate around three different axes. With this configuration, minute positioning of a three-dimensional object is possible. Further, in the above-described embodiment, an example using a coil spring has been described. However, in addition to using the coil spring for tension, similar effects can be obtained by using other springs such as a spiral spring or a leaf spring singly or in combination. Can be. Further, by adding a damper to give a damping effect to the joint, the operation can be further stabilized. Further, in the above embodiment, only the part that opens and closes three fingers with two actuators is a robot hand. However, an actuator is added to rotate or translate the entire structure shown here collectively. A mechanism can be added, and the whole can be regarded as one robot hand.

Embodiment 2 FIG. FIG. 8 shows a second embodiment of the present invention. FIG. 8 is a plan view showing the structure of the finger portion as viewed from a direction perpendicular to the actuator drive shaft 4. In the figure, 8A and 8B both denote compression springs for applying a rotational torque to the link 6, and the same components as those shown in FIG. Omitted.

Next, the operation will be described. In the figure,
The both ends of the spring 8A are fixed to the link 3 and the link 6, respectively. One end of the spring 8B is fixed to the link 6, but the other end is free. When the link 6 rotates around the joint 5 by a certain angle, one free end contacts the link 3 to apply a counterclockwise rotation torque to the link 6. Similar to the first embodiment, the object is grasped and exercised, but the gripping force is generated only by the spring 8A up to a certain rotation angle, and when the angle is exceeded, both the springs 8A and 8B generate the gripping force. Is different from the first embodiment. As a result, a wider gripping force than in the first embodiment can be generated. In the above embodiment, an example in which two compression springs are used has been described. However, in the same manner as in the first embodiment, a combination with another spring or a damper can be added. Also,
An actuator can be added.

Embodiment 3 FIG. FIG. 9 is a configuration diagram showing a third embodiment of the present invention.
In the figure, 23 is a leaf spring, 24 is an external force, 25 is an external force 2
4 indicates the direction in which the link 6 rotates. The other components that are the same as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description thereof will be omitted.

Next, the operation will be described. The operation of gripping a normal object and giving a motion to the object is realized by the spring 8 in the same manner as in the first embodiment. The difference from the first embodiment is a case where an external force acts on the link 6 in the direction of the arrow 24 when, for example, the robot arm is controlled to move the robot hand to the work position. In the first embodiment, the rotation of the link 6 in the direction of the arrow 25 around the joint 5 is prevented by the stopper 9. However, in the example shown here, the leaf spring 23 suppresses the rotation. As a result, the link 6 can rotate in the direction of 25, and the rotation can reduce the external force 24. Therefore, even if the detection of the external force 24 is delayed and the control of the actuator is slightly delayed, the robot hand and the robot arm can be prevented from being damaged. In the above-described embodiment, the case where the joint is supported by two springs has been described. However, similar effects can be obtained by combining other types of springs, such as using one spring for tension and compression. Can be obtained. Furthermore, by adding a damping characteristic to the joint by adding not only a spring but also a brake, a damper, and the like, it is possible to further stabilize the operation when the object is gripped.

Embodiment 4 FIG. FIGS. 10, 11 and 12 show a fourth embodiment of the present invention. FIG. 10 is a configuration diagram showing the configuration of the robot hand according to the fourth embodiment . FIGS. 11 and 12 are plan views viewed from a direction perpendicular to the actuator rotation axis for explaining a state in which an object is gripped. . In the figure, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted. The shape is almost the same as that of the first embodiment , except that the link 3 actively controlled by the actuator 2 does not end at the joint 5 but extends to almost the same position as the link 6. Link 3 corresponds to the first link, and link 6 corresponds to the second link.

Next, the operation will be described. The normal gripping state is the same as that of the first embodiment, and by using the link 3 and the link 6 together, it is possible to finely position the object while holding the object. The difference is in the method of generating a strong gripping force. First, FIG. 11 shows a case where the object 10 is gripped so as to be sandwiched between the links 6. When the object 10 is held between the links 6 and held, the actuator 2
Is controlled to close the link 3, the link 6 is gradually opened by receiving a force from the object 10, and at some point the positions of the link 3 and the link 6 become equal. When the link 6 is inside the link 3, the gripping force is obtained by the force generated by the spring 8 that rotates the joint 5. However, when the position of the link 3 is equal to that of the link 6, the gripping force is generated by the actuator 2. The torque is directly transmitted from the link 3 to the object 10 as a gripping force, and a strong gripping force is obtained.

Next, referring to FIG.
And a case where it is gripped so as to be surrounded by the link 6. Object 10
When the link 3 is closed by controlling the actuator 2 from a state where the link 3 is surrounded by the link 3 and the link 6, the link 6 is gradually opened by receiving a force from the object 10 and the link 3 is opened at a certain time. The positions of the links 6 become equal, and the object 10 comes into contact with the respective links 3 at two places. When the link 6 is inside the link 3, the gripping force is obtained by the force generated by the spring 8 that rotates the joint 5. However, the positions of the link 3 and the link 6 become equal, and the object 10 and the link 3 When you come in contact at two places,
The torque generated by the actuator 2 is directly transmitted from the link 3 to the object 10 as a gripping force, and a strong gripping force is obtained.

Embodiment 5 FIG. FIG. 13 shows a fifth embodiment of the present invention. In the figure, 26 is a drag acting on the object 10 from the link 3, 27
Indicates a frictional force acting on the object 10 from the link 3, 28 indicates a resultant force acting on the object 10 from the link 3 that combines the drag 26 and the frictional force 27, and 29 indicates a direction in which the object 10 moves by the resultant force 28. In other respects, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. Object 10
When moving in the direction of 9, the left and right links 3 are closed simultaneously and the object 10 is slid on the arc of the link 3. At this time, the tangential frictional force 27 and the normal surface drag 26 act on the object 10 from the link 3. Since the portion where the link 3 contacts the object 10 is formed in an arc shape, even when the link 3 is rotated, the angle formed by the tangent line between the link 3 and the object 10 with the movement direction 29 of the object 10 increases. Therefore, the component of the resultant force 28 acting on the object 10 in the movement direction 29 increases, and the movement of the object 10 is smoothly realized. In the above-described embodiment, the shape of the portion of the link 2 that is in contact with the object is a perfect arc. However, the shape does not have to be a perfect arc, and the same effect can be obtained with a convex surface having a large curvature.

Embodiment 6 FIG. FIG. 14 is a configuration diagram showing a sixth embodiment of the present invention. In the figure, reference numeral 30 denotes an object 1 when the object 10 is gripped.
Projections provided so that the thickness of the fingers is equal at both ends of 0, 3
Reference numeral 1 denotes a flange provided on the object 10 so that an axial force of the object 10 can be easily transmitted from the finger to the object 10,
In other respects, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. In FIG. 14, the number of fingers on the near side of the object 10 is one, whereas the number of fingers behind the object 10 is two. . Therefore, by attaching protrusions 30 having different heights to the link 3 on each side, the thickness of the fingers on both sides of the object 10 is made equal. As a result, when moving the object 10 in its axial direction, the object 10
Even if a slip occurs between the link 3 and the link 6, the protrusions 30 on both sides are simultaneously provided on the flange 31 provided on the object 10.
And an axial force can be applied to the object 10. In the above embodiment, the case where the projection is attached to a part of the finger is shown. However, the same effect can be obtained by changing the thickness of the finger itself so that the height of the finger is equal on both sides of the object. Can be obtained. In the above embodiment,
Although the projection is provided on the link 3, the same effect can be obtained by providing the projection on the link 6.

Embodiment 7 FIG. FIG. 15 shows a seventh embodiment of the present invention. In the figure, 32 is an actuator for changing the length of the spring,
Reference numeral 33 denotes an arm for transmitting the output of the actuator 32 to the position where the spring is mounted. In other respects, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. When a strong gripping force is not required, the actuator 32 is operated to move the power transmission arm 33 to the position shown in the drawing, and the spring grips the object in the state of 8C. On the other hand, when a strong gripping force is required, the actuator 32 is operated to grip the object with the spring at 8D. By doing so, the spring is 8C
As a result, the force generated by the spring increases, and a strong gripping force is obtained.

Embodiment 8 FIG . FIGS. 16, 17 (A), (B) and 18 show the present invention.
Example 8 is shown. FIG. 16 is an enlarged perspective view of the fingertip portion,
17 (A) and 17 (B) are cross-sectional views of a grip portion showing a state in which an object having a different thickness is gripped by the tip of a finger, and FIG. 18 is a diagram in which a small object is gripped in the middle of a finger. FIG. 4 is a plan view illustrating a state in which the finger has been viewed from a direction parallel to a rotation axis of a finger. In the figure, 7A and 7B indicate a finger with a thick tip, 7C indicates a finger with a thin tip, and other components that are the same as those shown in FIG. Omitted.

Next, the operation will be described. FIG. 17 (A)
Indicates a case where the thick object 10 is gripped, and the object 10 and the finger 7
A and 7B are in contact at a part of the chamfered surface away from the center. On the other hand, FIG.
Is shown, and the object 10 and the fingers 7A and 7B are in contact with each other at a portion near the center of the chamfered surface. If the processing of chamfering by changing the thickness of the fingertip is not performed, the finger and the object touch at the corners, but even if an object with a different thickness is gripped by such processing, the object Is in contact with the part of the finger that has been processed into a planar shape, so that the grip is stable. In the above-described embodiment, the case of chamfering is shown, but the same effect can be obtained even with arc-shaped processing having a small curvature.

FIG. 18 shows a situation where a small object is gripped. When the fingers 7A and 7C are closed due to the small size of the object 10, the tips of the fingers intersect. Can be gripped without any problems.

Embodiment 9 FIG. FIG. 19 shows a ninth embodiment of the present invention . In FIG. 19, reference numeral 34 denotes a region where the friction coefficient is increased, and reference numerals 35 and 36 denote regions where the friction coefficient is reduced. In other respects, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. As shown in the first embodiment, when the object is gripped so as to be sandwiched between the ends of the link 6, the object 10 and the link 6 are in contact with each other in the area 34 having a large friction coefficient even when an external force acts on the object 10. Does not slip off link 6. Also,
Similarly, as shown in the first embodiment, when the object 10 is gripped so as to be surrounded by the link 3 and the link 6, a slip occurs between the object 10 and the link 3 and the link 6 in order to give motion to the object 10. There must be. Since the object 10 comes into contact with the regions 35 and 36 where the friction coefficient between the link 6 and the link 3 is small, the object 10 can easily slip and give the object 10 a smooth motion.

Embodiment 10 FIG. FIG. 20 shows a tenth embodiment of the present invention. In the figure, reference numeral 37 denotes a gear attached to one end of the link 6, and 38 denotes a joint angle sensor which meshes with the gear 37 and detects a joint angle. In other respects, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. First, when the object is gripped by operating the actuator, the force received by the link 6 from the object is equal to the force generated by the spring 8. This rotation angle is detected by a joint angle sensor 38 via a gear 37. Since the mounting position of the spring is known in advance, the extension of the spring 8 can be calculated from the joint angle. Next, the force generated by the spring 8 is calculated from the rigidity of the spring. The direction of the spring 8 can also be calculated from the joint position data and the joint angle, and the torque generated by the spring 8 is obtained using this.

[0053]

As described above, according to the present invention, a plurality of fingers, a hand body for connecting the plurality of fingers to another device, and a posture of each finger with respect to the hand body. In the robot hand having an actuator for changing, the finger has a drive shaft to the actuator.
A first link mounted and driven via the first link;
The end of the link is rotatably connected to the center of the link by a rotary joint, and the second link is disposed closer to the gripping object than the first link. Since a spring is connected between the first link and the second link and attached so as to generate a rotational force, and a gripping force is generated by the spring or the actuator, a simple configuration is provided. Thus, the function of positioning the object and the function of reducing the impact force can be realized, and a robot hand capable of easily generating the force even when a large gripping force is required is obtained.

Further, since the side of the second link that grips the object is an arcuate curved surface, and the object is brought into contact with this curved surface and gripped, the movement for positioning the object can be performed smoothly, so that the cost can be reduced. There is an effect that a device that can realize a stable positioning operation can be obtained.

Further, since the thickness of each finger is changed so that the ends of the fingers in the direction along the object when gripping the object are equal on both sides of the object, a large gripping force is generated. Even if it is not possible, a large force is applied to the object and the object can be attached to and detached from the device, so that the device can be reduced in size and weight, and the actuator can be configured at a low cost because it requires only a small output actuator.

[0056] Further, in the robot hand attached to three fingers to rotate around parallel axes, 3
When the fingers are rotated, they are provided close to each other with an interval that can slip through each other, and the tip of the finger located inside is thinned,
The other two fingers have thicker tips and chamfered portions of the gripping surface near the above-mentioned fingers, so that the object has a wide range without complicating the structure. There is an effect that the user can operate the device by grasping it.

[0057] Also, by increasing the friction coefficient of the other fingers and the surface facing the tip portion of the farthest link from Ha command body,
Conversely, by reducing the coefficient of friction of the region of each finger opposite to the other finger except the region, without particularly complicating the structure, when gripping an object with the tip of the finger When the gripping is stabilized and the object is gripped by surrounding it with four or more links, there is an effect that the motion given to the object can be smoothed .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a robot hand according to a first embodiment of the present invention.

FIG. 2 is a perspective view illustrating an operation of the robot hand according to the first embodiment of the present invention.

FIG. 3 is a perspective view illustrating an operation of the robot hand according to the first embodiment of the present invention.

FIG. 4 is a plan view illustrating an operation of the robot hand according to the first embodiment of the present invention.

FIG. 5 is a plan view illustrating the operation of the robot hand according to the first embodiment of the present invention.

FIG. 6 is a plan view illustrating an operation of the robot hand according to the first embodiment of the present invention.

FIG. 7 is a plan view illustrating the operation of the robot hand according to the first embodiment of the present invention.

FIG. 8 is a plan view showing a robot hand according to Embodiment 2 of the present invention.

FIG. 9 is a perspective view showing a robot hand according to Embodiment 3 of the present invention.

FIG. 10 is a perspective view showing a robot hand according to Embodiment 4 of the present invention.

FIG. 11 is a plan view illustrating an operation of the robot hand according to the fourth embodiment of the present invention.

FIG. 12 is a plan view illustrating an operation of the robot hand according to the fourth embodiment of the present invention.

FIG. 13 is a plan view showing a robot hand according to Embodiment 5 of the present invention.

FIG. 14 is a perspective view showing a robot hand according to Embodiment 6 of the present invention.

FIG. 15 is a plan view showing a robot hand according to Embodiment 7 of the present invention.

FIG. 16 is a perspective view showing a robot hand according to Embodiment 8 of the present invention.

FIG. 17 is a sectional view illustrating an operation of the robot hand according to the eighth embodiment of the present invention.

FIG. 18 is a sectional view illustrating the operation of the robot hand according to the eighth embodiment of the present invention.

FIG. 19 is a perspective view showing a robot hand according to Embodiment 9 of the present invention.

FIG. 20 is a plan view showing a robot hand according to Embodiment 10 of the present invention.

FIG. 21 is a perspective view illustrating a usage form of a general robot hand.

FIG. 22 is a perspective view showing a conventional robot hand.

FIG. 23 is a perspective view showing a conventional robot hand.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Robot main body, 2 actuators, 3 links driven by an actuator, 4 axes for transmitting the driving force of an actuator to the link, 5 rotary joints, 6 passively rotating links, 7 entire fingers, 8 springs, 9 stoppers, 10 gripping Object, 11 Link 3 movement, 12 Link 6 movement, 13 Grasping object movement, 14 Link 3
Movement, 15 movement of link 6, 16 movement of grasped object, 17 movement of link 3, 18 movement of link 6, 1
9 movement of grasped object, 20 movement of link 3, 21 movement of link 6, 22 movement of grasped object, 23 leaf spring,
24 external force, 25 direction of rotation by external force, 26 surface drag, 27 frictional force, 28 resultant force, 29 direction of object movement, 30 protrusion attached to finger, 31 flange attached to object, 32 length of spring changed Actuator, 33 Arm for transmitting the power of the actuator to the mounting position of the spring, 34 Area for increasing the coefficient of friction, 35
Area to keep the coefficient of friction small, 36 area to keep the coefficient of friction small, 37 gears, 38 joint angle sensors,
39 drive mechanism, 40 finger movement, 41 flexible tube, 42
Wire rope, 43 robot arm, 44 robot hand.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-49-21391 (JP, A) JP-A-4-105,891 (JP, A) JP-A-63-251186 (JP, A) 120489 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B25J 15/08

Claims (5)

(57) [Claims] 1. A robot hand, comprising: a plurality of fingers; a hand body that couples the plurality of fingers to be attached to another device; and an actuator that changes an attitude of each finger with respect to the hand body. The finger is attached to the actuator via a drive shaft and driven, and a first link is rotatably connected to a center of the first link by a rotary joint at an end thereof, and is gripped by the first link. And a second link disposed on the object side, and connects a spring between the first link and the second link so as to generate a rotational force around the rotation axis of the rotary joint. And a gripping force generated by the spring or the actuator. 2. An arcuate side of the second link for gripping an object.
2. The robot hand according to claim 1, wherein the robot hand has a shape of a curved surface, and an object is brought into contact with the curved surface to grip the object . 3. It has three or more fingers, and each finger has a thickness.
Change the direction along the object when gripping the object
So that the positions of the ends of the fingers are equal on both sides of the object.
According to claim 1 or 2, wherein the robot hand, characterized in that the. 4. The method according to claim 1, wherein the plurality of fingers move around a parallel axis.
It consists of three fingers rotated by a tutor, and the three
When you rotate your fingers
Provided close to, and narrow the tip of the finger located inside,
The other two fingers have thicker tips and a gripping surface.
Be sure to chamfer the part near the finger above.
The robot hand according to claim 1, wherein: 5. The coefficient of friction of the surface of a finger facing another finger,
The tip should be large and the other parts small.
The robot hand according to claim 1, wherein: