JP2023165035A - Driving mechanism of robot hand having multiple fingers and robot hand - Google Patents

Abstract

To provide a driving mechanism which enables fingers of a robot hand to grip an object highly accurately and stably regardless of the shape of the object.SOLUTION: There is provided a driving mechanism enabling, by driving power of one actuator, fingers of a robot hand to grip an article, the robot hand comprising a first finger arranged at a center of one end side of a palm, and a second finger and a third finger spaced apart from each other on the other end side of the palm. A driving power transmission device of the drive mechanism comprises: a first differential device and a second differential device. The first differential device includes: a first finger-side shaft configured to transmit the driving power to the first finger and arranged on one end side of a driving-side case to which the driving power of the actuator is transmitted; and a side shaft arranged on the other end side of the driving-side case. The second differential device includes: a second finger-side shaft configured to transmit the driving force to the second finger and arranged on one end side of a driven-side case to which the driving power transmitted to the side shaft is transmitted; and a third finger-side shaft configured to transmit the driving force to the third finger and arranged on the other end side of the driven-side case.SELECTED DRAWING: Figure 37

Description

The present invention relates to a drive mechanism for a robot hand having a plurality of fingers, and a robot hand equipped with the drive mechanism.

2. Description of the Related Art A robot hand that operates a plurality of fingers using one actuator as a drive source is known (for example, see Patent Document 1). In the robot hand described in Patent Document 1, two four-bar link mechanisms are constructed with a plurality of links including the proximal, middle, and distal fingers, and one actuator drives the plurality of fingers, and each In a finger, the proximal, middle, and distal segments can be rotated around three joints.

JP2019-063886A

The robot hand as shown in Patent Document 1 adopts a configuration in which the three joints of the finger are driven by two four-bar link mechanisms consisting of seven links, so that the base joint of the finger can be driven by a single finger. , the middle segment and the terminal segment can each independently move relatively freely according to the shape of the object. As a result, if the object has a uniform thickness, it can be reliably gripped with one actuator.

However, the robot hand cannot accurately position the robot hand with respect to the object, or when the object has a different diameter and the shape is uneven, such as when the thickness of the object changes greatly in the axial direction. Under certain circumstances, when moving multiple fingers, the proximal, middle, and distal phalanges of all fingers cannot move relatively independently according to the shape of the object, so it is difficult to accurately move the object. Unable to grasp well. Under these circumstances, there is a need for a drive mechanism and a robot hand that can grasp an object with high precision and stability, regardless of the shape of the object.

A drive mechanism according to one aspect of the present invention is a drive mechanism for the fingers of a robot hand that has three fingers and grips an article by transmitting the driving force of one actuator. The three fingers are arranged at the center of one end of the palm surface of the main body of the robot hand, and the first finger is spaced apart from the other end of the palm surface. The driving force transmission device includes a driving side case to which the driving force of the actuator is transmitted, and a driving force transmission device provided at one end side of the driving side case, and transmitting the driving force to the first finger. a first differential device including a first finger-side shaft that transmits the driving force and a side shaft provided on the other end side of the driving-side case; a driven-side case to which the driving force transmitted to the side shaft is transmitted; A second finger side shaft provided at one end of the driven case and transmitting the driving force to the second finger; and a third finger side provided at the other end of the driven case and transmitting the driving force to the third finger. and a second differential device including a shaft.

A robot hand according to one aspect of the present invention includes the above drive mechanism, three joint angle sensors that are associated with each of the three fingers and detect joint angles of a plurality of joints in each finger, and an output shaft of an actuator. Based on the motor shaft sensor that detects the input rotation angle corresponding to the rotation angle of and a control unit that determines whether the drive mechanism is operating normally, the control unit detecting a value detected by the motor shaft sensor and a value detected by the joint angle sensor associated with the first finger. Based on the rotation angle of the side shaft obtained from the rotation angle of the drive side case and the rotation angle of the first finger side shaft, first rotation angle data indicating the rotation angle of the driven side case is obtained, and The rotation angle of the second finger side shaft obtained from the detection value by the joint angle sensor associated with the third finger, and the rotation angle of the third finger side shaft obtained from the detection value of the joint angle sensor associated with the third finger. is used to obtain second rotation angle data indicating the rotation angle of the driven side case, and based on the first rotation angle data and second rotation angle data, it is determined whether the drive mechanism is operating normally. It is.

Further, a drive mechanism according to one aspect of the present invention is a finger drive mechanism of a robot hand that has three fingers and grips an article by transmitting the driving force of one actuator. It includes a differential device that distributes the transmitted driving force, and has a driving force transmission device that connects the actuator and each finger, and the three fingers are arranged at the center of one end side of the palm surface of the main body of the robot hand. The differential device includes a first finger, a second finger, and a third finger, which are spaced apart from each other on the other end of the palm surface. A second finger side shaft provided at one end side and transmitting the driving force to the second finger; a third finger side shaft provided at the other end side of the case and transmitting the driving force to the third finger; A first torsion spring fixed to the case and having the other end fixed to the second finger side shaft; and a second torsion spring having one end fixed to the case and the other end fixed to the third finger side shaft. It is something.

According to the drive mechanism according to the present invention, the driving force transmitted from the actuator is distributed to the three fingers via the differential device, so that the object can be driven with high precision and stability regardless of the shape of the object. It can be held. According to the robot hand equipped with the drive mechanism, even objects with different diameters can be accurately and stably gripped.

FIG. 1 is a perspective view of a robot hand 1 based on Embodiment 1 of the present invention. FIG. 2 is a perspective view of the robot hand 1 seen from the opposite direction to FIG. FIG. 3 is a front view showing the posture before gripping the workpiece W1 (object W1). FIG. 4 is a front view showing a posture in which the fingers 2A are in contact with the object W1 when gripping the work W1 (object W1). FIG. 5 is a front view showing a posture in which the workpiece W1 (object W1) is gripped. FIG. 6 is a front view showing the posture in which the workpiece W1 (object W1) is gripped, and the gripping posture is different from that in FIG. FIG. 7 is a front view showing a posture in which the workpiece W1 (object W1) is gripped, and the gripping posture is different from that in FIGS. 5 and 6. FIG. 8 is a perspective view of the robot hand 1 based on the second embodiment of the present invention. FIG. 9 is a perspective view from the fingertip side showing the drive mechanism for the finger 2 in the robot hand 1 shown in FIG. FIG. 10 is a perspective view from the fingertips showing the drive mechanism. FIG. 11 is a rear view from the fingertips showing the drive mechanism. FIG. 12 is a link configuration diagram modeling and explaining link elements in the drive mechanism. FIG. 13 is a perspective view showing the structure of the proximal segment 111. FIG. 14 is a perspective view showing the structure of the middle section 121. FIG. 15 is a perspective view showing the structure of the distal segment 131. FIG. 16(a) is a perspective view showing the structure of the drive link 114, and FIG. 16(b) is a perspective view showing the structure of the drive link 114 seen from the opposite side from FIG. 16(a). FIG. 17 is a perspective view showing the structure of the base relay link 113. FIG. 18 is a perspective view showing the structure of the intermediate link plate 120. FIG. 19 is a perspective view showing the structure of the distal relay link 123. FIG. 20 is a side view showing the posture of the fingers before gripping the object. FIG. 21 is a side view showing the posture when fingers grip a thin object. FIG. 22 is a perspective view showing the posture when fingers grip a cylindrical workpiece W2 (object W2). FIG. 23 is a side view showing a state immediately before the fingers grip the cylindrical workpiece W2 (object W2). FIG. 24 is a side view showing the posture when the middle joint 121 contacts the cylindrical workpiece W2 (target object W2) from the state shown in FIG. FIG. 25 is a side view showing the posture when the fingertip 139 contacts the cylindrical work W2 (object W2) and gripping is completed from the state shown in FIG. 24. FIG. 26 is a perspective view showing the posture when fingers grip a conical workpiece W3 (object W3). FIG. 27 is a side view showing the posture when fingers grip a conical workpiece W3 (object W3). FIG. 28 is a side view of the posture when fingers grip a conical workpiece W3 (object W3) when viewed from the opposite direction to FIG. 27. FIG. 29 is a side view of the side view shown in FIG. 28, in which only the object is drawn in cross section at the part where the finger (2B) on the near side and the workpiece W3 (object W3) come into contact. FIG. 30 is a side view of the side view shown in FIG. 28, in which only the object is drawn in cross section at the part where the central finger (2A) and the workpiece W3 (object W3) are in contact. FIG. 31 is a side view of the side view shown in FIG. 28, in which only the object is drawn in cross section at the part where the finger at the back (2C) and the workpiece W3 (object W3) are in contact. FIG. 32 is a perspective view of the drive mechanism for the finger 2 in the robot hand 1 according to the third embodiment of the present invention, viewed from the fingertip side. FIG. 33 is a perspective view of the drive mechanism viewed from the fingertips. FIG. 34 is a rear view of the drive mechanism viewed from the fingertips. FIG. 35 is a perspective view of the drive mechanism for the finger 2 in the robot hand 1 according to the fourth embodiment of the present invention, viewed from the fingertip side. FIG. 36 is a perspective view of the drive mechanism viewed from the fingertips. FIG. 37 is a rear view of the drive mechanism viewed from the fingertips. FIG. 38 is a perspective view showing the posture when fingers grip a workpiece W4 (target object W4) having a different diameter shape. FIG. 39 is a side view showing the posture when fingers grip a workpiece W4 (object W4) having a different diameter shape. FIG. 40 is a side view of the posture when the fingers grip a workpiece W4 (object W4) having a different diameter when viewed from the opposite direction to FIG. 39. FIG. 41 is a side view of the side view shown in FIG. 40, in which only the object is drawn in cross section at the part where the finger (2B) on the near side and the workpiece W4 (object W4) come into contact. FIG. 42 is a side view of the side view shown in FIG. 40, in which only the object is drawn in cross section at the part where the central finger (2A) and the workpiece W4 (object W4) are in contact. FIG. 43 is a side view of the side view shown in FIG. 40, in which only the object is drawn in cross section at the part where the finger at the back (2C) and the workpiece W4 (object W4) are in contact. FIG. 44 shows a robot hand 1 according to Embodiment 1 of the present invention in which a linear motion device with a self-locking mechanism [e.g. a trapezoidal screw] is replaced with a linear motion device without a self-locking mechanism [e.g. a ball screw]. FIG. 3 is a front view showing a posture in which a workpiece W1 (object W1) is gripped by a robot hand. Figure 45 shows a state in which the gripping position of the object has changed due to the differential operation of the differential device with the actuator in the servo lock state (in a situation where the motor output shaft does not rotate) in that hand (the hand in Figure 44). It is a front view. FIG. 46 is a perspective view showing the type and shape of the object. FIG. 46(a) shows a cylindrical shape, FIG. 46(b) shows a conical shape, and FIG. 46(c) shows an example of an object having different diameters.

Embodiments of the present invention will be described in detail below with reference to the drawings.
[Example 1]
FIG. 1 is an overall view of a robot hand 1 according to a first embodiment of the present invention as seen diagonally from above, and FIG. 2 is an overall view of the robot hand 1 as seen from the opposite direction to FIG. 3 to 7 are front views showing the operation when gripping the workpiece W1 (object W1).
In FIGS. 1 and 2, the robot hand 1 is connected to the robot main body (not shown) via a base frame 5 so as to drive two fingers 2 (2A, 2B) to perform work such as gripping a work object. is attached to. Note that this robot hand 1 is mounted on, for example, a humanoid robot, an arm-type robot, or the like, and cooperates with other robots to realize various tasks smoothly.

The two fingers 2 (2A, 2B) are configured to function by moving opposing surfaces corresponding to finger pads toward or away from each other by transmitting the driving force of one actuator.

The actuator 11, such as an electric motor, outputs driving force by driving and rotating a transmission shaft 31 via a transmission device 11T that includes a built-in planetary gear and has functions such as deceleration. The actuator 11 is fixed to the base frame 5.
A drive gear 31G is fixed to the distal end of the transmission shaft 31 so as to coaxially rotate therewith. Note that if deceleration or the like is not required, the drive gear 31G may be fixed directly to the tip of the output shaft of the actuator 11 without using the transmission device 11T so as to rotate coaxially therewith.
Drive gear 31G meshes with driven gear 33G, which serves as a ring gear in differential device 41, so that the driving force of actuator 11 is transmitted to differential case 42.

The differential device 41 includes a differential case 42, a pinion gear (not shown) disposed inside the differential case 42, side gears (also not shown), and side shafts 51, 61. Further, the differential device 41 is supported on the base frame 5 so as to be immovable in the axial direction and freely rotatable.
The side shaft 51 is integrally formed with or fixed to a side gear (not shown), and the side shaft 61 is fixed to another side gear (not shown) such that they cannot rotate relative to each other.
The rotation axes of the side shaft 51 and the side shaft 61 are arranged to be coaxial, and although they are immovable in the axial direction of the rotation axes with respect to the differential case 42 and the base frame 5, they are rotatable around the rotation axes. It is pivoted on.

Further, as shown in FIGS. 1 and 2, the driven gear 33G is immovable relative to the differential case 42 so that its rotation axis is coaxial with the rotation axis of the side shaft 51 and the rotation axis of the side shaft 61. Fixed.
With this configuration, the output of the actuator 11 is transmitted to the differential case 42 via the transmission shaft 31, the drive gear 31G, and the driven gear 33G.
In the first embodiment, a transmission mechanism using the drive gear 31G and the driven gear 33G is used to transmit the output of the actuator 11 to the differential case 42, but other transmission mechanisms may be used. For example, a driving pulley is fixed to the tip of the transmission shaft 31 so as to coaxially rotate therewith, and a driven pulley is fixed to the differential case 42 so as to be coaxial with the rotation axis of the side shaft 51 and the rotation axis of the side shaft 61 so that it cannot rotate relative to the differential case 42. A transmission mechanism may be used in which the output of the actuator 11 is transmitted to the differential case 42 by fixing the actuator 11 to the differential case 42 and wrapping a transmission belt around both the drive pulley and the driven pulley.

By meshing a pinion gear (not shown) disposed inside the differential case 42 with a side gear (not shown), the side shaft 51 (first side gear) and the side shaft 61 (another side gear) are connected to the differential case 42. Differential motion occurs between the two.
The differential device 41 of the first embodiment is constituted by a general differential device that uses a pinion gear (not shown) and a bevel gear as a side gear (not shown). In addition, as long as differential motion is generated between the side shaft 51 and the side shaft 61, for example, the pinion gear and the side gear as proposed by the inventors in Japanese Patent Application No. 2019-182275, A differential device using gears whose movements are constrained relative to each other by dimensional curves may also be used.

Here, as shown in FIG. 1, a drive pulley 61P is fixed to the tip of the side shaft 61 so as to rotate together on the same axis, and similarly, as shown in FIG. A drive pulley 51P is fixed to the drive pulley 51P so as to rotate together on the same axis.
The transmission devices 21A and 21B that transmit the driving force from the drive pulleys 51P and 61P to the fingers 2A and 2B are coaxially fixed to the side shafts 51 and 61 that output the driving force via the differential device 41. The drive pulleys 51P, 61P, transmission belts 52, 62, driven pulleys 53P, 63P, screw shafts 22A, 22B, and screw nuts 23A, 23B are coaxially fixed to these pulleys. The screw shafts 22A and 22B are the finger-side output shafts of the differential device 41, which allows driving force to be transmitted from the input side to the output shaft via the screw shaft 22. It forms a self-locking mechanism that prevents external forces and load forces from being transmitted to the input shaft.
That is, in the self-locking transmission device 21 shown in FIGS. 1 to 7, the screw nut 23 is rotated along the linear guide 24 by rotating the screw shaft 22, which is the input shaft, in both forward and reverse directions. Although it is possible to generate linear motion in both the forward and reverse directions, the screw nut 23 does not move even if an external force or load force is applied that would cause the screw nut 23 to move in a straight line in both the forward and reverse directions. The screw shaft 22 also cannot be rotated. In addition, in Example 1, a trapezoidal screw is used for the screw shaft 22.

A driven pulley 53P is fixed to the tip of the screw shaft 22A so as to rotate together on the same axis, and by wrapping the transmission belt 52 around both the drive pulley 51P and the driven pulley 53P, the output of the actuator 11 is transferred to the screw shaft. 22A, and is configured to generate a linear motion of the finger 2A integral with the screw nut 23A.
Similarly, a driven pulley 63P is fixed to the tip of the screw shaft 22B so as to rotate together on the same axis, and by wrapping the transmission belt 62 around both the driving pulley 61P and the driven pulley 63P, the output of the actuator 110 is is transmitted to the screw shaft 22B to generate linear motion of the finger 2B integral with the screw nut 23B.
Note that the screw shaft 22A and the screw shaft 23B are configured with opposite threads.
With this configuration, in the no-load state, the side shaft 51 and the side shaft 61 are rotationally driven while maintaining their relative positional relationship with the differential case 42, and the rotational movement of the actuator 11 is caused by the movement of the fingers 2A and 2B. Generated as an opening and closing motion.

The object grasping operation by the hand 1 of the first embodiment will be described using FIGS. 3 to 5. FIG.
Note that these figures are front views showing the postures before and after gripping the object W1.
FIG. 3 is a front view showing the posture before gripping the object W1, and shows a no-load state. When the actuator 11 is driven in the state shown in FIG. 3, the side shaft 51 and the side shaft 61 are rotated while maintaining the relative positional relationship with the differential case 42, and as described above, the fingers 2A and 2B open and close. is generated.
FIG. 4 is a front view showing a state in which the actuator 11 is driven so that the fingers 2A and 2B move to close from the state shown in FIG. 3, and the finger 2A is in contact with the object W1. In the state shown in FIG. 4, when the actuator 11 is further driven so that the fingers 2A and 2B are closed, the rotational movement of the side shaft 51 stops, and the side shaft 61 rotates twice as much as the rotational movement of the differential case 42. Performs rotational motion at high speed. That is, the linear motion (closing motion) of the finger 2A is not generated, and only the linear motion (closing motion) of the finger 2B is generated.
FIG. 5 is a front view showing a state in which the finger 2B comes into contact with the object W1 from a state in which no linear motion (closing motion) of the finger 2A is generated and only a linear motion (closing motion) of the finger 2B is generated. be. Thereby, grasping of the object W1 by the hand 1 is realized.

As can be seen from the behavior shown in FIGS. 3 to 5, even if the object W1 is not located at the center of the fingers 2A and 2B before grasping, or if the object W1 is a different-diameter object with an uneven shape, Even in this case, the differential device 41 generates a differential movement in the side shafts 51 and 61, the fingers on the contact side stop, and the fingers on the non-contact side rapidly approach the object, resulting in a reliable gripping operation. It turns out that it is possible to achieve this.
In general, when a robot grasps the position of an object by visual recognition (e.g. recognition using a camera) or environmental recognition (recognition using radar etc.), there are errors in these recognitions and it is difficult to grasp the object stably. It can sometimes have an impact. Even in such a case, the robot hand 1 of the first embodiment can realize stable gripping without being affected by the recognized position error of the object.

When the object W1 is gripped by the robot hand 1 and transported at high speed (the work is rapidly decelerated at the target position), an inertial force acts on the object W1 when it stops, and this inertia The force becomes an external force to the robot hand 1. In addition, even when grasping an object with an indefinite center of gravity (for example, an object containing liquid and air in a container whose center of gravity changes as the liquid moves) or a moving object (for example, an animal), it is possible to An external force generated by movement of the center of gravity of the object itself acts on the robot hand 1.
In the first embodiment, by providing the transmission device 21 with a self-locking mechanism on the output side (the side where the finger 2 is located) of the differential device 41, the robot hand 1 is subjected to an external force (for example, as indicated by the arrow in FIG. 5). Even if an external force (external force) acts on the side shafts 51, 61, no differential movement occurs, and reliable gripping is achieved between the fingers 2A and 2B.

Here, a case where the transmission device 21 with a self-locking mechanism is not provided will be described.
44 and 45 show a target object W1 when the transmission device 21 with a self-locking mechanism of Embodiment 1 is replaced with linear motion devices 221A and 221B (for example, a drive device using a ball screw) without a self-locking mechanism. It shows a grasping posture.
FIG. 44 shows a posture in which the object W1 is gripped.

In FIG. 44, when an external force is applied to the robot hand 1 in the direction of arrow A, the side shaft 51 and A differential movement occurs at 61, and as shown in FIG. 45, the position and orientation of the gripped object W1 change while being gripped.
On the other hand, if the transmission device 21 with a self-locking mechanism is used, for example, the robot arm can move the object W1 at high speed in the direction of arrow A while gripping it, instantly stop it at the target position, and move the object W1 in the direction of arrow A. Even when a large inertial force acts on the object W1, the self-locking transmission device 21 can prevent the position and posture of the object W1 from changing.

As described above, in the first embodiment of the present invention, the driving force of one actuator 11 is distributed to the side shafts 51 and 61 by the differential device 41, and the self-locking transmission devices 21A and 21B are driven. By adopting this, it is possible to not only realize stable gripping without being affected by the recognition position error of the object, but also to realize stable gripping even against external forces acting on the robot hand 1.
In addition, as shown in FIG. 5, the robot hand 1 can perform optimal tasks such as grasping by controlling the control unit 1C to acquire the linear movement position of the fingers 2 (finger 2A and finger 2B) and realizing drive according to the object. It is designed to do this. In this embodiment, a case will be described in which a control unit 1C is installed in the robot hand 1 to centrally control the operation, but the invention is not limited to this, and for example, the robot body on which the robot hand 1 is installed. It may also be applied to a form where the system is centrally controlled.

The control unit 1C of the robot hand 1 is composed of a central processing element, a so-called CPU (Central Processing Unit), which executes a control program stored in a memory 1M. The control unit 1C controls, for example, the forward and reverse drive of the actuator 11 based on various parameters preset in the memory 1M and various sensor information obtained from an angle sensor, which will be described later. With the work W1 as the work target, work such as gripping is performed under optimal conditions.
Specifically, the control unit 1C of the robot hand 1 is connected to an encoder 11E that detects the rotation angle of the drive output shaft of the actuator 11. The control unit 1C detects the rotation angle of the differential case 42, which is also the input rotation angle of the differential device 41, based on the detection information of the encoder 11E. The rotation angle of the differential case 42 can be detected based on the rotation angle of the drive output shaft of the actuator 11 detected by the encoder 11E, the reduction ratio of the transmission device 11T, and the reduction ratio of the drive gear 31G and the driven gear 33G. good.

Further, a reading magnet 53rm, which is one component of the rotation sensor element, is fixed to the outer surface of one side of the screw shaft 22A so as to rotate together on the same axis. In addition, the reading head 53rh, which is the other component of the rotation sensor element, is installed on a member that rotatably supports the screw shaft 22A, is located around the reading magnet 53rm, and is connected to the control unit 1C. has been done.
The control unit 1C adjusts the lead of the screw shaft 22A (the distance that the nut 23 moves along the linear guide 24 with one rotation of the screw shaft 22) based on the relative rotation information of the reading magnet 53rm detected by the reading head 53rh. Based on this, the position (translational position) of the finger 2A is directly detected and acquired.
In this embodiment, a case where the finger-side output sensor detects the rotation angle of the screw shaft 22A to obtain the position of the finger 2A will be described as an example; however, the present invention is not limited to this, and for example, a differential device may be used. A reading magnet 53rm', which is one component of the rotation sensor element, is fixed to the outer surface of one side of the side shaft 51, which is the output shaft of the rotation sensor element, so as to rotate together on the same axis. A certain reading head 53rh' is installed on a member that rotatably supports its side shaft 51 and is positioned around the reading magnet 53rm', detects the rotation angle of the side shaft 51, and collects the detected rotation information. Based on the reduction ratio of the driving pulley 51P, driven pulley 53P, and transmission belt 52, and the lead of the screw shaft 22A (the distance that the nut 23 moves along the linear guide 24 with one rotation of the screw shaft 22), the finger It may be applied to a form in which the position (translational position) of 2A is directly detected and acquired. Further, a reading magnet 53rm'', which is one component of the position sensor element, is integrally fixed to the nut 23A, and the reading head 53rh'', which is the other component of the position sensor element, is made to be freely translatable through the nut 23A. It is installed on the supporting member and is located around the translational movement of the reading magnet 53rm'', detects the position (translational position) of the nut 23A, and determines the position of the finger 2A based on the detected position (translational position). It may also be applied to a form in which (translational position) is directly detected and acquired.

Similarly, a reading magnet 63rm, which is one component of the rotation sensor element, is fixed to the outer surface of one side of the screw shaft 22B so as to rotate together on the same axis. In addition, the reading head 63rh, which is the other component of the rotation sensor element, is installed on a member that rotatably supports the screw shaft 22B, is located around the reading magnet 63rm, and is connected to the control unit 1C. has been done. The control unit 1C directly detects and acquires the position (translational position) of the finger 2B based on the lead of the screw shaft 22B based on the relative rotation information of the reading magnet 63rm detected by the reading head 63rh.
In this embodiment, a case where the finger side output sensor detects the rotation angle of the screw shaft 22B to obtain the position of the finger 2B will be described as an example; however, the present invention is not limited to this, and for example, a differential device may be used. A reading magnet 63rm', which is one component of the rotation sensor element, is fixed to the outer surface of one side of the side shaft 61, which is the output shaft of the rotation sensor element, so as to rotate integrally on the same axis. A certain reading head 63rh' is installed on a member that rotatably supports its side shaft 61 and is positioned around the reading magnet 63rm', detects the rotation angle of the side shaft 61, and collects the detected rotation information. Based on the reduction ratio of the driving pulley 61P, driven pulley 63P, and transmission belt 62, and the lead of the screw shaft 22B (the distance that the nut 23 moves along the linear guide 24 with one rotation of the screw shaft 22), the finger The present invention may be applied to a form in which the position (translational position) of 2B is directly detected and acquired. Further, a reading magnet 63rm'', which is one component of the position sensor element, is integrally fixed to the nut 23B, and the reading head 63rh'', which is the other component of the position sensor element, is made to be freely translatable through the nut 23B. It is installed on the supporting member and is located around the translational movement of the reading magnet 63rm", detects the position (translational position) of the nut 23B, and determines the position of the finger 2B based on the detected position (translational position). It may also be applied to a form in which (translational position) is directly detected and acquired.

In addition, the control unit 1C determines the gripping status of the workpiece based on the detected and acquired positions of the fingers 2A and 2B.
Specifically, if the position of the finger 2A and the position of the finger 2B do not change even though the actuator 11 is driven by a command from the control unit 1C, it is determined that there is a "possibility of grasping the object". Deciding. Grip the workpiece W by comparing and referencing the gripping object information (shape of the workpiece W, assumed positional distance between the fingers 2A and fingers 2B when the workpiece W is gripped as expected) and the acquired information set in advance in the memory 1M. judging the situation.

The work W1 shown in FIGS. 5 to 7 is the same object, and has a rectangular cross section when viewed from the front of the robot hand 1 (the viewpoint direction in which FIGS. 5 to 7 are illustrated). 5 shows the workpiece W1 being gripped in the short side direction, FIG. 6 shows the workpiece W1 being gripped in the long side direction, and FIG. 7 shows the workpiece W1 being gripped in the long side direction. The diagram shows gripping in a diagonal direction (of a rectangular cross section).
When the workpiece W1 is to be gripped in the short side direction according to a command from the control unit 1C, the assumed positional interval between the fingers 2A and 2B when the workpiece W1 is gripped in the short side direction is stored in the memory 1M. I'll keep it. Then, the positional interval between the fingers 2A and 2B calculated from the detected and acquired position of the finger 2A and the position of the finger 2B is compared with the assumed positional interval set in advance in the memory 1M, and if the comparison results match, then FIG. As shown in , the control unit 1C determines that the workpiece W1 is being gripped in the short side direction.
If the comparison results do not match, the control unit 1C determines that the workpiece W1 is not gripped in the short side direction (the gripping situation shown in FIG. 5, such as the gripping situation shown in FIGS. 6 and 7, is not the same), and performs the gripping operation. Start over.

Further, the control unit 1C controls the drive mechanism of the robot hand 1 based on the detection information of the encoder 11E, the relative rotation information of the reading magnet 53rm detected by the reading head 53rh, and the relative rotation information of the reading magnet 63rm detected by the reading head 63rh. We are verifying the system.
That is, as described above, the control unit 1C detects the rotation angle of the differential case 42, which is also the input rotation angle of the differential device 41, based on the detection information of the encoder 11E.
Further, the control unit 1C detects the rotation angle of the side shaft 51 based on the relative rotation information of the reading magnet 53rm detected by the reading head 53rh, and based on the reduction ratio of the driving pulley 51P, the driven pulley 53P, and the transmission belt 52. get.
In addition, the control unit 1C controls the rotation angle of the side shaft 61 based on the relative rotation information of the reading magnet 63rm detected by the reading head 63rh and the reduction ratio of the drive pulley 61P, driven pulley 63P, and transmission belt 62. Get detected.

If the detected rotation angle of the side shaft 51, the rotation angle of the side shaft 61, and the rotation angle of the differential case 42 satisfy the following formula (1) based on the allowable error (sensor resolution and sensor detection accuracy error), control is performed. The unit 1C determines that the drive mechanism system of the robot hand 1 is operating normally.
(Rotation angle of side shaft 51 + rotation angle of side shaft 61) ÷ 2
=Rotation angle of differential case 42...(1)

However, play in the transmission device 11T, drive gear 31G, driven gear 33G, and differential device 41, tooth skipping due to gear tooth wear, belt elongation and out-of-step of the belt transmission mechanism by the drive pulley 51P, transmission belt 52, and driven pulley 53P, If belt elongation or synchronization of the belt transmission mechanism consisting of the drive pulley 61P, transmission belt 62, and driven pulley 63P occurs, or if the rotation angle sensor (11E, 53rh, 53rm, 63rh, 63rm) becomes loose or malfunctions, it may become difficult to grasp the object. Regardless of the presence or absence state, the above formula (1) will no longer be satisfied.
In such a case, the control unit 1C determines that the drive mechanism system of the robot hand 1 is not operating normally.
In addition, if the self-locking transmission device 21 becomes loose or the nut 23 and the finger 2 become loose, a known object whose dimensional information (geometrical relationship) is known in advance cannot be gripped as expected. Even in this case, the positional interval between the fingers 2A and 2B calculated from the detected and acquired positions of the finger 2A and the finger 2B does not match the assumed positional interval preset in the memory 1M.
Even in such a case, the control unit 1C determines that the drive mechanism system of the robot hand 1 is not operating normally.

[Example 2]
8 to 31 are diagrams showing a robot hand 1 based on a second embodiment of the present invention. When compared with Example 1, the difference is in the transmission device with a self-locking mechanism and the presence or absence of joints provided in each finger.
Specifically, in the first embodiment, a transmission device 21 with a self-locking mechanism is used, which is composed of a screw shaft 22 and a screw nut 23, but in the second embodiment, it is composed of a cylindrical worm 26 and a worm wheel 27. A transmission device 25 with a self-locking mechanism is used.
Further, the fingers 2 (2A, 2B) of Example 1 have no joints, but the fingers 2 (2A, 2B, 2C) of Example 2 have a metacarpophalangeal joint 112, a proximal interphalangeal joint 122, The fingers have joints such as the distal interphalangeal joint 132, and in addition, the fingers 2 (2A, 2B, 2C) of Example 2 operate multiple joints with one driving force source, and each finger is It is composed of an underdrive mechanism that allows the constituent nodes to fit along the outer surface of the workpiece W.

In FIGS. 8 to 11, the robot hand 1 is connected to a robot (not shown) via the wrist 109 so that the three fingers 2 (2A, 2B, 2C) are respectively driven to perform work such as gripping a work object. It is attached to the main body side. Note that this robot hand 1 is mounted on, for example, a humanoid robot, an arm-type robot, or the like, and cooperates with other robots to smoothly perform various tasks.
The robot hand 1 has fingers 2 arranged at three locations on a palm surface 106 of a palm (robot hand main body) 105 attached to a wrist 109 to grip a work object, etc., and one end side of the palm surface 106. Fingers 2B and 2C are arranged at both ends of 106a, and finger 2A is arranged at the center of the opposite end 106b. These fingers 2A to 2C grip the work object by relatively rotating the proximal joint 111, middle joint 121, and distal joint 131 in a direction in which they approach between the end sides 106a and 106b of the palm surface 106. It is laid out so that you can

The three fingers 2 (2A, 2B, 2C) are driven by power generated from one actuator 11, and all have the same structure. Furthermore, the three fingers 2 (2A, 2B, 2C) include a metacarpophalangeal joint 112, a proximal interphalangeal joint 122, and a distal interphalangeal joint 132, and the driving force from one actuator is applied to each of the three fingers 2 (2A, 2B, 2C). The configuration is such that the movement of each finger is generated by transmitting the signal to the finger drive link 114. Since each finger has the same structure, the same reference numerals are used for the parts that make up the fingers unless otherwise specified. In addition, if it is necessary to clearly indicate which finger part it is, whether it is a part of finger 2A, a part of finger 2B, or a part of finger 2C, use the code *A or *B and *C are given. For example, the drive link 114 of finger 2A is written as drive link 114A.

The finger 2 has one end side of the base phalanx 111 connected and supported in a relatively rotatable manner to a metacarpophalangeal joint 112 arranged on the palm surface 106 side of the palm 105 (which may be on the same surface, inside or outside), The other end side of the proximal segment 111 and one end side of the middle segment 121 are connected and supported to the proximal interphalangeal joint 122 so as to be relatively rotatable, and the other end side of the middle segment 121 and one end side of the distal segment 131 are connected and supported to be relatively rotatable. The distal interphalangeal joint 132 is relatively rotatably connected and supported, and the other end side of the distal interphalangeal joint 131 functions as a fingertip 139 to be described later.
This finger 2 includes a proximal four-bar link mechanism 103 that includes the proximal segment 111 as a link, and a distal four-bar link mechanism 104 that includes the middle segment 121 and the distal segment 131 as links (see FIG. 12). It is constructed to function by relatively rotating each of the base joint 111, middle joint 121, and distal joint 131 by transmitting the driving force of the two actuators 11.

As will be described later, the proximal four-bar link mechanism 103 and the distal four-bar link mechanism 104 are each arranged so that the four links form a trapezoid that approximates a triangle, and the individual links rotate relative to each other. freely connected.
In the proximal four-bar link mechanism 103, a proximal relay link 113 is arranged on the side opposite to the proximal joint 111, and the proximal joint 111 and the finger base (palm surface 106) side of the proximal relay link 113 are connected by a drive link 114. At the same time, the fingertip 139 side is connected by the base intermediate link 115. The proximal phalanx 111 is rotatably connected on the fingertip side by the end of the drive link 114 and the metacarpophalangeal joint 112, and on the fingertip 139 side is rotatably connected by the end of the proximal intermediate link 115 and the proximal interphalangeal joint 122. freely connected. The base relay link 113 is rotatably connected to the end of the drive link 114 and the first connecting shaft 116 on the fingertip side, and rotatably connected to the end of the base intermediate link 115 and the second connecting shaft 117 on the fingertip 139 side. is connected to.

In the distal four-bar link mechanism 104, a distal relay link 123 is arranged on the opposite side to the middle joint 121, and the finger base sides of the middle joint 121 and the distal relay link 123 are connected by a distal intermediate link 125. , the fingertip 139 side is connected by the distal joint 131. The middle phalanx 121 is rotatably connected on the fingertip side by the end of the distal intermediate link 125 and the proximal interphalangeal joint 122, and on the fingertip 139 side is rotatably connected by the end of the distal phalanx 131 and the distal interphalangeal joint 132. freely connected. The distal relay link 123 has a fingertip side rotatably connected to the end of the distal intermediate link 125 and the third connecting shaft 126, and a fingertip 139 side rotatably connected to the end of the distal link 131 and the fourth connecting shaft 127. connected.

The proximal intermediate link 115 and the distal intermediate link 125 share a proximal interphalangeal joint 122 located at the top of one of the intermediate link plates 120 (see FIG. 18) that are formed in a generally triangular plate shape. The ends of the base joint 111 and the middle joint 121 are rotatably connected by using a second connecting shaft 117 and a third connecting shaft located at the other two tops of the triangle of the intermediate link plate 120. The end portions of the proximal relay link 113 and the distal relay link 123 are rotatably connected to the base relay link 126 to function.
That is, the intermediate link plate 120 fixes the relative positional relationship of the proximal interphalangeal joint 122 and the second and third connecting shafts 117 and 126, and the proximal intermediate link 115 and While maintaining the relative posture of the distal intermediate link 125, the connected state is maintained such that the distal intermediate link 125 can rotate freely around its proximal interphalangeal joint 122. Therefore, the intermediate link plate 120 includes a link that rotates around the proximal interphalangeal joint 122 while maintaining the relative positional relationship between the second and third connecting shafts 117 and 126. Therefore, the base relay link 113, the base intermediate link 115, the distal intermediate link 125, and the distal intermediate link 123, which are rotatably connected to the second and third connecting shafts 117 and 126, are interlocked. to transmit the motion to.

The distal joint 131 rotatably connects the fingertip 139 side of the middle joint 121 and the distal relay link 123 while maintaining the distance between the distal interphalangeal joint 132 on both ends and the fourth connecting shaft 127, and By making the fingertip 139, which is shaped to be spaced apart from the distal interphalangeal joint 132 in the extension direction of the middle phalanx 121, relatively rotatable while the relative positional relationship with respect to the fourth connecting shaft 127 is also fixed, the fingertip 139 can be rotated. It is designed to function as a fingertip. That is, the distal interphalangeal joint 132, the fourth connecting shaft 127, and the fingertip 139 are configured to be rotatable while the relative positional relationship of the three locations is fixed.

As shown in the model diagram of the links constituting the drive mechanism for finger 2 (see Figure 12), in the proximal four-bar linkage mechanism 103, the proximal joint 111, which is part of the length of the finger 2, and the proximal The relay link 113 is formed to have the same length, and the proximal intermediate link 115 is formed to be about 1/3 shorter than the drive link 114, which has a thickness near the metacarpophalangeal joint 112 of the finger 2. has been done. Similarly, in the distal four-bar link mechanism 104, the middle segment 121, which is part of the length of finger 2, and the distal relay link 123 are formed to have the same length, and the proximal phalanx of finger 2 is The distal joint 131 is formed to be shorter than half of the distal intermediate link 125, which has a thickness near the joint 122, and is about ⅓ as short as the distal intermediate link 125.

Therefore, when the finger 2 is stretched as much as possible, in the base four-bar link mechanism 103, the base relay link 113 and the base intermediate link 115 are in a posture that continues as linearly as possible, A second connecting shaft 117 that rotatably connects the proximal relay link 113 and the proximal intermediate link 115 is a line segment between the proximal interphalangeal joint 122 and the first connecting shaft 116 on both ends thereof. By approaching L1 (first virtual link 119, which will be described later) on the outside, it is manufactured so as to form a shape that roughly approximates a triangle as a whole. In the distal four-section link mechanism 104, the distal relay link 123 and the distal section 131 are in a continuous posture as straight as possible, and the distal relay link 123 and the distal section 131 are rotatably connected. The four connecting shafts 127 approach the line segment L2 (second virtual link 129 described later) between the third connecting shaft 126 on both ends thereof and the distal interphalangeal joint 132 on the outside, so that the overall shape is approximately It is manufactured to form a shape that approximates a triangle.

With this configuration, in the proximal four-bar linkage mechanism 103, when no load is applied to the proximal joint 111 etc. to limit movement, the relative connection posture (link It is possible to rotate around the metacarpophalangeal joint 112 while maintaining its shape (shape). This proximal four-bar linkage mechanism 103, for example, when the proximal joint 111 hits a work object and is subjected to a limiting load that stops the movement, the metacarpophalangeal joint 112 is connected to the proximal joint 111 to be stopped. The proximal intermediate link 115 (distal intermediate link 125) connects the proximal interphalangeal joint 122 to allow the proximal relay link 113 to move toward the fingertip 139 in conjunction with the drive link 114 that rotates around the Rotate around the center. In this base four-bar link mechanism 103, the base intermediate link 115 is formed to be shorter than half of the drive link 114, so that the distal intermediate link 125 on the fingertip 139 side of the base relay link 113 can be rotated greatly. The range of rotation at the proximal interphalangeal joint 122 can be increased. In this embodiment, the base intermediate link 115 is made to have a dimension that is less than half the size of the drive link 114, but if the drive link 114 is longer than the base intermediate link 115, the above function can be achieved. Needless to say.

At this time, in the distal four-bar link mechanism 104, similarly to the proximal four-bar link mechanism 103, if no load is applied to the middle phalanx 121 or the like to limit movement, the proximal interphalangeal joint 122 is moved. It is possible to rotate around the proximal interphalangeal joint 122 while maintaining the connected posture (link shape) relative to the proximal intermediate link 115 that rotates around the base intermediate link 115 and the integral distal intermediate link 125. This distal four-bar linkage mechanism 104 is connected to the proximal interphalangeal joint relative to the middle phalanx 121 to be stopped when a limiting load is applied to stop the movement, such as when the middle phalanx 121 hits a work object. The distal phalanx 131 rotates about the distal interphalangeal joint 132 in conjunction with the distal intermediate link 125 rotating about the distal interphalangeal joint 122 to allow the distal relay link 123 to move toward the fingertip 139.

Also in this distal four-bar link mechanism 104, the distal link 131 is formed to be shorter than half of the distal intermediate link 125, so the distal link 131 on the fingertip 139 side of the distal relay link 123 can be rotated greatly. The range of rotation at the distal interphalangeal joint 132 can be increased. In this embodiment, the end link 131 is made to have a size less than half of the end intermediate link 125, but it goes without saying that if the end intermediate link 125 is longer than the end link 131, the above-mentioned function can be achieved.
Thereby, the distal phalanx 131 can rotate the fingertips 139 whose relative positional relationship (posture) is fixed around the distal interphalangeal joint 132 and abut against the work target, and the proximal phalanx 111 and The workpiece can be gripped together with the middle section 121.

Specifically, as shown in FIG. 13, the base joint 111 is configured by forming shaft holes 111a and 111b at both ends of a pair of base joint plates 111P that are connected and fixed by an intermediate frame 111F. . As shown in FIG. 14, the middle section 121 is constructed by having support shafts 121S1 and 121S2 fixed to both ends of a pair of middle section plates 121P that are connected and fixed by an intermediate frame 121F, respectively, so as to function as shafts. There is. As shown in FIG. 15, the distal segment 131 has a shaft hole 131a formed at one end side of a pair of distal segment plates 131P that are connected and fixed by a fingertip frame 131F, and one end side is coupled and fixed to the fingertip frame 131F. A shaft hole 131b is formed at the other end of the support plate 131S.

Further, as shown in FIG. 16, the drive link 114 is configured by forming shaft holes 114a and 114b at both ends of a drive link plate 114P, respectively. As shown in FIG. 17, the base relay link 113 is configured by forming shaft holes 113a and 113b at both ends of a pair of base relay link plates 113P that are connected and fixed by an intermediate frame 113F. As shown in FIG. 18, the base intermediate link 115 and the distal intermediate link 125 are configured by forming shaft holes 120a, 120b, and 120c at the triangular tops of the intermediate link plate 120, respectively. . As shown in FIG. 19, the distal relay link 123 is configured by forming shaft holes 123a and 123b at both ends of a pair of distal relay link plates 123P that are connected and fixed by an intermediate frame 123F.

Specifically, one end side of the pair of proximal plates 111P is rotatably supported by a connecting shaft 114S, which is a finger-side output shaft of a differential device 41, which will be described later, inserted into a shaft hole 111a (see FIG. 16). ). As a result, one end side of the proximal joint 111 is connected to the metacarpophalangeal joint 112 (the shaft hole 111a and the connecting shaft 114S) so as to be relatively rotatable.
Furthermore, a connecting shaft 114S, which will be described later, is inserted into a shaft hole 114a and fixed at one end of the pair of driving link plates 114P. As a result, one end of the drive link 114 is connected to the metacarpophalangeal joint 112 (the shaft hole 114a and the connection shaft 114S) so as to rotate together.

As shown in FIG. 14, one end of the pair of middle segment plates 121P is formed with a narrow distance between them so as to be located between the other end of the proximal segment plate 111P, and the support shaft 121S1 is fixed between them. Both ends of the support shaft 121S1 protrude from the outer surface of one end. The other end side of the pair of proximal joint plates 111P is rotatably supported by fitting both ends of the support shaft 121S1 of the middle joint plate 121P into the shaft hole 111b. Similar to the base plate 111P, the top of one end of the intermediate link plate 120 is rotatably supported by a support shaft 121S1 of the intermediate link plate 121P inserted into the shaft hole 120a. As a result, the other end side of the proximal phalanx 111, one end side of the middle phalanx 121, and one end side of the proximal intermediate link 115 and the distal intermediate link 125 are connected to the proximal interphalangeal joint 122 (shaft holes 111b, 120a and They are relatively rotatably connected by a support shaft 121S1).

Further, the other end side of the pair of middle segment plates 121P is formed at a distance equal to that of the proximal segment plate 111P so that one end side of the terminal segment plate 131P is located between them, and the support shaft 121S2 is fixed between them. There is. One end side of the pair of end joint plates 131P is rotatably supported by a support shaft 121S2 of the middle joint plate 121P inserted into the shaft hole 131a. Thereby, the other end side of the middle segment 121 and one end side of the distal segment 131 are connected to each other through the distal interphalangeal joint 132 (the shaft hole 131a and the support shaft 121S2) so as to be relatively rotatable.

Shaft holes 113a and 113b formed at both ends of the base relay link plate 113P shown in FIG. 17, shaft holes 114b formed at the other end of the drive link plate 114P shown in FIG. 16, and an intermediate link plate shown in FIG. Connecting shafts 116S and 117S (see FIG. 17) of the first connecting shaft 116 and the second connecting shaft 117 are inserted into the shaft hole 120b formed at the base side top of the shaft hole 120, respectively, and are connected to the shaft hole 120b so as to be relatively rotatable. . As a result, the first connecting shaft 116 and the second connecting shaft 117 (shaft holes 113a, 113b and They are relatively rotatably connected by connecting shafts 116S, 117S).

Shaft holes 123a and 123b formed at both ends of the distal relay link plate 123P shown in FIG. 19, a shaft hole 120c formed at the distal top of the intermediate link plate 120 shown in FIG. 18, and a support plate 131S shown in FIG. Connecting shafts 126S and 127S (see FIG. 19) of the third connecting shaft 126 and the fourth connecting shaft 127 are respectively inserted into the shaft hole 131b and are connected to each other so as to be relatively rotatable. As a result, both ends of the distal relay link 123, the other end of the distal intermediate link 125, and the other end of the distal link 131 are connected to the third connecting shaft 126 and the fourth connecting shaft 127 (shaft holes 123a, 123b and connecting The shafts 126S, 127S) are connected for relative rotation.

By the way, the fingertip frame 131F located between the pair of distal phalanx plates 131P shown in FIG. 139 to function suitably. One end of the support plate 131S that is separated from the other end where the shaft hole 131b is formed is fixed to one side of the fingertip frame 131F with screws. Thereby, the distal link 131 is connected to be relatively rotatable around one or both of the shaft holes 131a and 131b on both ends, and functions as one of the links forming the distal four-bar link mechanism 104.

As shown in FIG. 10, the proximal interphalangeal joint 122 and the distal interphalangeal joint 132 include a proximal phalanx plate 111P and a middle phalanx plate 121P, and a middle phalanx plate 121P and a distal phalanx plate 131P. So-called torsion springs (elastic members) 141 and 142, which apply elastic force so as to extend approximately linearly, are positioned around each of the support shafts 121S1 and 121S2 (see FIG. 14). has been done. The torsion springs 141 and 142 are stretched when, for example, the middle segment plate 121P rotates with respect to the proximal segment plate 111P, and the distal segment plate 131P with respect to the middle segment plate 121P rotates in a direction from an unloaded state toward each other. It is installed so as to provide an elastic force that biases it in the direction of returning to the posture.

Furthermore, as shown in FIGS. 13 to 15, abutment surfaces 111t1, 121t1, 121t2, and 131t2 are arranged around these torsion springs 141 and 142, respectively, to function as stoppers to limit excessive rotation. . As shown in FIG. 13, the abutment surface 111t1 is formed on one side in the reverse rotation direction of the longitudinal end face away from the shaft hole 111b of the proximal plate 111P, and one side in the rotation direction is formed in a circular shape to prevent rotation. However, since it is located on the opposite rotation direction side and is formed into a square shape, it abuts against the opposite side and functions to limit reverse rotation. As shown in FIG. 14, the abutting surface 121t2 is formed on an opposing surface facing the abutting surface 111t1 of the proximal segment plate 111P near the shaft hole 121a of the middle segment plate 121P, and abuts against the abutting surface 111t1. functions to limit its reverse rotation. Similarly, as shown in FIG. 14, the abutment surface 121t1 is formed on one side in the reverse rotation direction of the longitudinal end surface remote from the shaft hole 121b of the middle section plate 121P, and one side in the rotation direction is circular. While it is formed to allow rotation, it is located in the opposite rotation direction and is formed in a rectangular shape so that it abuts against the opposing side and functions to limit reverse rotation. As shown in FIG. 15, the abutment surface 131t2 is formed on an opposing surface facing the abutment surface 121t1 of the middle section plate 121P near the shaft hole 131a of the end section plate 131P, and abuts against the abutment surface 121t1. It functions to limit its reverse rotation.

The abutment surfaces 111t1, 121t2 and the abutment surfaces 121t1, 131t2 move from the state in which the proximal phalanx plate 111P, the middle phalanx plate 121P, and the middle phalanx plate 131P approach each other to the proximal interphalangeal joint 122 and the distal interphalangeal joint 122. They are formed so that they rotate about the joint 132 in a direction returning to the stretched position by the elastic force of the torsion springs 141 and 142, and when they try to further rotate from the stretched position, they collide with each other. As a result, the proximal phalanx plate 111P, the middle phalanx plate 121P, and the middle phalanx plate 131P are prevented from rotating too much from the stretched posture, so that they can be maintained in the state where they have returned to the stretched posture, and the finger 2 can be maintained in the stretched posture. Warping can be reliably prevented. That is, the torsion springs 141, 142 and the abutting surfaces 111t1, 121t1, 121t2, 131t2 constitute posture maintaining means.

Note that the shapes of the abutment surfaces 111t1, 121t1, 121t2, and 131t2 are not limited to the shapes shown in FIGS. 13 to 15 employed in the second embodiment.
That is, in the second embodiment, the abutting surface 111t1 is provided in a planar shape near the proximal interphalangeal joint 122 of the proximal phalanx 111, and the abutting surface 121t2 is provided in a planar shape near the proximal interphalangeal joint 122 of the middle phalanx 121. It is set up in The planar abutment surface 111t1 and the planar abutment surface 121t2 are formed so as to abut against each other when the proximal section 111 and the middle section 121 are about to further rotate from the stretched posture. By having a planar shape that abuts against each other, the stoppers are configured and installed as a stopper that has enough strength to receive a large force.

Similarly, a planar abutting surface 121t1 is provided near the distal interphalangeal joint 132 of the middle phalanx 121, and a planar abutting surface 131t2 is provided near the distal interphalangeal joint 132 of the distal phalanx 131. The planar abutment surface 121t1 and the planar abutment surface 131t2 are formed so as to abut against each other when the middle section 121 and the distal section 131 try to further rotate from the stretched posture. By having a planar shape that abuts against each other, the stoppers are configured and installed as a stopper that has enough strength to receive a large force.
Thereby, the finger 2 can stand by in a posture in which the proximal phalanx plate 111P, the middle phalanx plate 121P, and the distal phalanx plate 131P extend substantially linearly when there is no load as shown in FIGS. 8 to 10, for example.

Furthermore, in FIGS. 8 to 10, a pair of proximal phalanx plates 111P in the metacarpophalangeal joint 112 of the finger 2 disposed in the palmar surface 106 of the palm 105 are connected to a shaft hole 114S on one end side, respectively. is inserted and supported so as to be relatively rotatable. On the other hand, the drive link plate 114P at the metacarpophalangeal joint 112 is rotatably supported by a connecting shaft 114S positioned between the proximal plates 111P and inserted into the shaft hole 114a at one end. At the same time, they each receive the driving force of the actuator 11 and are driven by being rotated in forward and reverse directions around the connecting shaft 114S (shaft hole 114a).

As shown in FIGS. 8 to 10 and 16, the drive link plate 114P of the finger 2 has a worm wheel 27 fixed to the outer circumferential side with the shaft hole 114a on one end side as the axis, and A connecting shaft 114S is fixed so as to be relatively unrotatable.
On the other hand, the actuator 11 outputs driving force by rotationally driving the transmission shaft 31 via a transmission device 11T that has a built-in planetary gear and has functions such as deceleration. A drive pulley 31P is fixed to the tip of the drive pulley 31 so as to rotate together on the same axis.

The cylindrical worm 26 that engages with the worm wheel 27 of the drive link plate 114P of the finger 2A is fixed to the axis of the cylindrical worm 26 so as to coaxially rotate together with a transmission shaft 157. A pulley 33P is fixed so as to coaxially rotate together. The transmission belt 32 is wound around both the driving pulley 31P and the driven pulley 33P, and transmits the output of the actuator 11 to the transmission shaft 157.

As a result, at the metacarpophalangeal joint 112A of the finger 2A, the driving force of the actuator 11 is transmitted at a reduced speed through the cylindrical worm 26A and the worm wheel 27A, and the drive link plate 114PA is rotated forward and backward. As shown in FIGS. 9 to 11 and 16, the drive link plate 114PA of the finger 2A has a worm wheel 27A fixed to the outer circumferential side with the shaft hole 114aA at one end as the axis, so that the driving force of the actuator 11 is At the same time, a connecting shaft 114SA is inserted into the shaft hole 114aA and fixed so as not to be relatively rotatable. In this embodiment, as will be described later, in order to detect the rotation angle of the drive link plate 114P, the connection shaft 114S is fixed so as not to rotate relative to the drive link plate 114P. If this is not necessary, it may be supported so that it can rotate relative to each other.

As shown in FIGS. 9 to 11 and 16, the drive link plate 114PB of the finger 2B has a worm wheel 27B fixed to the outer circumferential side with the shaft hole 114aB at one end as the axis, similarly to the finger 2A. The driving force of the actuator 11 is transmitted to the fingers 2A, 2C through a different path, and a connecting shaft 114SB, which is separate from the fingers 2A, 2C, is inserted into the shaft hole 114aB and fixed so as not to be relatively rotatable. Note that, similarly to the finger 2A, in this embodiment, in order to detect the rotation angle of the drive link plate 114P as described later, the connecting shaft 114S is fixed so as not to rotate relative to the drive link plate 114P. If it is not necessary to detect the rotation angle of 114P, it may be supported so as to be relatively rotatable.

Specifically, the path through which the driving force of the actuator 11 is transmitted to the transmission shaft 157 is the same as that for the finger 2A, but the driving force transmitted to the transmission shaft 157 is transmitted to the finger 2B. The routes are different.
That is, the drive gear 34G is fixed to the axial center of the transmission shaft 157 so as to coaxially rotate therewith.
Drive gear 34G meshes with driven gear 36G, which serves as a ring gear constituting differential device 41, so that the driving force of actuator 11 is transmitted to differential case 42.

The differential device 41 includes a differential case 42, a pinion gear (not shown) disposed inside the differential case 42, side gears (also not shown), and side shafts 51, 61. Further, the differential device 41 is fixed and free in the axial direction within the palm 105 with respect to the not-illustrated frame of the robot hand 1 so that it is driven and rotated when the driving force of the actuator 11 is transmitted. Rotatably supported.
The side shaft 51 is integrally formed with or fixed to a side gear (not shown), and the side shaft 61 is fixed to another side gear (not shown) such that they cannot rotate relative to each other.
The rotation axes of the side shaft 51 and the side shaft 61 are arranged to be coaxial, and are immovable in the axial direction of the rotation axes with respect to the differential case 42 and the frame (not shown) of the robot hand 1. , is rotatably supported around a rotation axis.

Further, as shown in FIGS. 10 and 11, the driven gear 36G is immovable relative to the differential case 42 so that its rotation axis is coaxial with the rotation axis of the side shaft 51 and the rotation axis of the side shaft 61. Fixed.
With this configuration, the output of the actuator 11 is transmitted to the differential case 42 via the drive pulley 31P, transmission belt 32, driven pulley 33P, transmission shaft 157, drive gear 34G, and driven gear 36G. There is.
In this embodiment, a transmission mechanism using a driving gear 34G and a driven gear 36G is used to transmit the output of the actuator 11 to the differential case 42, but other transmission mechanisms may be used.
For example, a driving pulley is fixed to the axial center of the transmission shaft 157 so as to coaxially rotate therewith, and a driven pulley is attached to the differential case 42 so as to be coaxial with the rotation axis of the side shaft 51 and the rotation axis of the side shaft 61. A transmission mechanism may be used in which the output of the actuator 11 is transmitted to the differential case 42 by fixing the actuator 11 so as not to be relatively rotatable and wrapping a transmission belt around both the drive pulley and the driven pulley.

By meshing a pinion gear (not shown) disposed inside the differential case 42 with a side gear (not shown), the side shaft 51 (first side gear) and the side shaft 61 (another side gear) are connected to the differential case 42. Differential motion occurs between the two.
In the differential device 41 of the present embodiment, a pinion gear (not shown) and a side gear (not shown) have their mutual movements restrained by a three-dimensional curve, for example, as proposed in Japanese Patent Application No. 2019-182275, as described above. It consists of a differential device using gears. In addition, if the differential device generates differential motion between the side shaft 51 and the side shaft 61, as shown in the first embodiment, a general method using bevel gears for the pinion gear (not shown) and the side gear (not shown) is possible. A standard differential device may also be used.

A driving pulley 51P is fixed to the tip of the side shaft 51 so as to coaxially rotate therewith, and a transmission belt 52 is wound thereon together with a driven pulley 53P. The driven pulley 53P is fixed to the axis of the driven pulley 53P so that the transmission shaft 177 coaxially rotates therewith. A cylindrical worm 26B is fixed to the opposite end of the transmission shaft 177 so as to coaxially rotate therewith. This cylindrical worm 26B is engaged with a worm wheel 27B of a drive link plate 114PB, in which a connecting shaft 114SB is inserted into a shaft hole 114aB on one end side, so that the cylindrical worm 26B can be rotated in forward and reverse directions.

As a result, in the metacarpophalangeal joint 112B of the finger 2B, the driving force of the same actuator 11 is transmitted to the transmission shaft 157, and the transmitted driving force is transmitted to the side shaft 51 of the differential device 41. The transmitted driving force is transmitted to the transmission shaft 177 via a belt transmission mechanism consisting of a driving pulley 51P, a transmission belt 52, and a driven pulley 53P, and is further transmitted to reduce speed via a cylindrical worm 26B and a worm wheel 27B. As a result, the drive link plate 114PB is rotated forward and backward. That is, regarding the drive of the finger 2B, the transmission shafts 31, 157, 177, the cylindrical worm 26B, the worm wheel 27B, the driving pulleys 31P, 51P, the driven pulleys 33P, 53P, the transmission belts 32, 52, the driving gear 34G, the driven gear 36G , the differential device 41, and the side shaft 51 constitute a driving force transmission device that transmits the driving force of the actuator 11.

As shown in FIGS. 9 to 11 and 16, the drive link plate 114PC of the finger 2C has a worm wheel 27C fixed to the outer circumferential side with the shaft hole 114aC at one end as the axis, similarly to the fingers 2A and 2B. The driving force of the actuator 11 is transmitted through a path separate from that of the fingers 2A and 2B, and a connecting shaft 114SC, which is separate from the fingers 2A and 2B, is inserted into the shaft hole 114aC and fixed so as not to rotate relative to each other. There is. Note that, similarly to the fingers 2A and 2B, in this embodiment, in order to detect the rotation angle of the drive link plate 114P as described later, the connecting shaft 114S is fixed so as not to rotate relative to the drive link plate 114P. If it is not necessary to detect the rotation angle of the link plate 114P, the link plate 114P may be supported so as to be relatively rotatable.

Specifically, the path through which the driving force of the actuator 11 is transmitted to the differential device 41 (driven gear 36G, differential case 42) is the same as that for the finger 2B. However, the route by which the driving force transmitted to the differential device 41 (driven gear 36G, differential case 42) is transmitted to the finger 2C is different.
A driving pulley 61P is fixed to the tip of the side shaft 61 so as to rotate together on the same axis, and a transmission belt 62 is wound around the driving pulley 61P together with a driven pulley 63P. A transmission shaft 187 is fixed to the axis of the driven pulley 63P so as to coaxially rotate therewith, and a cylindrical worm 26C is fixed to the opposite end of the transmission shaft 187 so as to coaxially rotate together with the driven pulley 63P. ing. This cylindrical worm 26C is engaged with a worm wheel 27C of a drive link plate 114PC, in which a connecting shaft 114SC is inserted into a shaft hole 114aC on one end side, so that the cylindrical worm 26C is rotated forward and backward.

As a result, the driving force of the same actuator 11 is transmitted to the differential device 41 (driven gear 36G, differential case 42) at the metacarpophalangeal joint 112C of the finger 2C. The transmitted driving force is transmitted to the side shaft 61 of the differential device 41, and the transmitted driving force is transmitted to the transmission shaft 187 via a belt transmission mechanism consisting of a driving pulley 61P, a transmission belt 62, and a driven pulley 63P. The drive link plate 114PC is rotated in the forward and reverse directions by being transmitted with a deceleration through the cylindrical worm 26C and the worm wheel 27C. That is, regarding the drive of finger 2C, transmission shafts 31, 157, 187, cylindrical worm 26C, worm wheel 27C, drive pulleys 31P, 61P, driven pulleys 33P, 63P, transmission belts 32, 62, drive gear 34G, driven gear 36G , the differential device 41, and the side shaft 61 constitute a driving force transmission device that transmits the driving force of the actuator 11.

Then, in the robot hand 1, the control unit 1C obtains the relative bending states of the proximal joint 111, middle joint 121, and distal joint 131 of the fingers 2A to 2C, and realizes a drive according to the object to optimally grasp the object. It is set to work. In this embodiment, a case will be described in which a control unit 1C is installed in the robot hand 1 to centrally control the operation, but the invention is not limited to this, and for example, the robot body on which the robot hand 1 is installed. It goes without saying that the present invention may also be applied to a form where the system is centrally controlled.

The control unit 1C of the robot hand 1 is composed of a central processing element, a so-called CPU (Central Processing Unit), which executes a control program stored in a memory 1M. The control unit 1C controls, for example, the forward and reverse drive of the actuator 11 based on various parameters preset in the memory 1M and various sensor information obtained from an angle sensor, which will be described later. A cylindrical workpiece W1 as shown in FIGS. 22 and 23 is used as a workpiece, and gripping and other work is performed under optimal conditions.

The control unit 1C of the robot hand 1 directly detects and acquires the operating status of the metacarpophalangeal joint 112 and the proximal interphalangeal joint 122 using sensor elements, which will be described later. is calculated and acquired using the acquired sensor information and dimensional information (geometric relationships) of each part stored in the memory 1M.
Specifically, as shown in the lower part of FIG. 16, a reading magnet 114rm, which is one component of the rotation sensor element, is embedded in one end of the connection shaft 114S. As shown in FIGS. 9 and 10, the reading head 114rh, which is the other component of the rotation sensor element, is a member on the palm 105 side that rotatably supports the connecting shaft 114S and functions as the metacarpophalangeal joint 112. It is installed around the reading magnet 114rm, and is connected to the control unit 1C. The control unit 1C directly detects the relative rotation angle 112α of the drive link plate 114P from the reference position R on the palm 105 side in the link model of the finger 2 shown in FIG. 12 from the relative rotation of the reading magnet 114rm detected by the reading head 114rh. get. In FIG. 11, the sensor wire connected to the control section 1C (the sensor wire between the control section 1C and the reading head 114rh) is shown by a dashed line.
In this embodiment, as a finger-side output sensor, the drive link plate 114P from the reference position R on the palm 105 side in the link model of the finger 2 shown in FIG. 12 is determined from the relative rotation of the reading magnet 114rm detected by the reading head 114rh. An example will be described in which the relative rotation angle 112α of the rotation sensor element is directly detected and obtained, but the invention is not limited to this. The reading head, which is the other component of the rotation sensor element, is installed on a member that rotatably supports the transmission shafts 157, 177, and 187. The rotation angle of the transmission shafts 157, 177, 187 is detected, and based on the detected rotation information, the reduction ratio by the self-locking transmission device 25 (25A, 25B, 25C) is determined. , the relative rotation angle 112α may be detected and acquired. Also, instead of detecting the rotation angle of the transmission shaft (177, 187), the rotation angle of the side shaft (51, 61) of the differential device 41 is detected, and based on the detected rotation information, the drive pulley (51P, 61P) ), transmission belts (52, 62), and driven pulleys (53P, 63P), as well as the reduction ratio of the self-locking transmission device 25 (25A, 25B, 25C), The present invention may be applied to a form in which the relative rotation angle 112α is detected and acquired.

In addition, as shown in FIG. 13, on one end side of the proximal plate 111P, a rotation sensor is installed on the outer surface of one side of a shaft hole 111a in which a connecting shaft 114S that rotates integrally with the drive link plate 114P is inserted and supported relatively rotatably. A reading magnet 111rm, which is one component of the element, is embedded and protrudes like a protrusion.
As shown in FIGS. 9 and 10, the reading head 111rh, which is the other component of the rotation sensor element, is a member on the palm 105 side that rotatably supports the connecting shaft 114S and functions as the metacarpophalangeal joint 112. It is located around the reading magnet 111rm, and is connected to the control unit 1C. The control unit 1C directly detects the relative rotation angle 112β of the proximal plate 111P from the reference position R on the palm 105 side in the link model of the finger 2 shown in FIG. 12 from the relative rotation of the reading magnet 111rm detected by the reading head 111rh. get. In FIG. 11, a sensor wire connected to the control section 1C (a sensor wire between the control section 1C and the reading head 111rh) is also shown by a dashed line.

Furthermore, as shown in FIG. 14, one end of the support shaft 121S1 protrudes from the outer surface of one end of the middle plate 121P, and a reading magnet 121rm, which is one component of the rotation sensor element, is embedded. There is. As shown in FIGS. 9 and 10, the reading head 121rh, which is the other component of the rotation sensor element, has one end of its support shaft 121S1 rotatably fitted into the shaft hole at the other end of the proximal plate 111P. 111b, and is connected to the control unit 1C. The control unit 1C directly obtains the relative rotation angle 122α of the middle segment plate 121P with respect to the proximal segment plate 111P from the relative rotation of the reading magnet 121rm detected by the reading head 121rh. In FIG. 11, the sensor wire connected to the control section 1C (the sensor wire between the control section 1C and the reading head 121rh) is also illustrated by a dashed line.

In this way, as shown in FIG. 12, the control unit 1C of the robot hand 1 moves the drive link plate 114P from the reference position R at the finger 2 based on the rotation information of the reading magnet 114rm detected by the reading head 114rh. The rotation angle 112α around the metacarpophalangeal joint 112 (axis holes 111a, 114a) is directly acquired, and the rotation angle 112α of the proximal phalanx plate 111P at the finger 2 is obtained based on the rotation information of the reading magnet 111rm detected by the reading head 111rh. The rotation angle 112β around the metacarpophalangeal joint 112 from the reference position R is directly acquired, and the rotation angle of the middle phalanx plate 121P relative to the proximal phalanx plate 111P is further determined based on the rotation information of the reading magnet 121rm detected by the reading head 121rh. The rotation angle 122α around the proximal interphalangeal joint 122 (axis holes 111b, 121a) is directly acquired.

On the other hand, the control unit 1C calculates and obtains the rotation angle 132γ of the distal interphalangeal joint 132 (shaft holes 121b, 131a) of the distal phalanx plate 131P relative to the middle phalanx plate 121P.
Specifically, first, the control unit 1C changes the rotation angle 112α of the drive link plate 114P from the reference position R to the rotation angle 112β of the proximal phalanx plate 111P from the reference position R around the metacarpophalangeal joint 112. By subtracting from , the rotation angle 112γ between the proximal plate 111P and the drive link plate 114P is calculated and obtained.

Next, the control unit 1C calculates the calculated rotation angle 112γ between the base joint plate 111P and the driving link plate 114P (hereinafter, the word plate may be omitted) and the link length of the base joint 111 (default). The length of the first virtual link 119 (the line segment L1 between the shaft holes 111b and 114b) is determined from the distance between the shaft holes 111a and 111b of the proximal plate 111P (hereinafter the same is omitted) and the link length of the drive link 114. Calculate and obtain.
Next, the control unit 1C calculates the proximity between the first virtual link 119 and the base joint 111 based on the calculated length of the first virtual link 119, the link length of the base joint 111, and the link length of the driving link 114. A rotation angle 122β around the interphalangeal joint 122 is calculated and obtained.

Next, similarly, the control unit 1C calculates the first virtual link 119 from the calculated length of the first virtual link 119, the link length of the base relay link 113, and the link length of the base intermediate link 115 in the intermediate link board 120. A rotation angle 122γ around the proximal interphalangeal joint 122 between the virtual link 119 and the proximal intermediate link 115 is calculated and obtained.
The control unit 1C calculates a calculated rotation angle 122β between the first virtual link 119 and the base joint 111, a calculated rotation angle 122γ between the first virtual link 119 and the base intermediate link 115, and the intermediate link plate 120. A fixed angle 122δ around the proximal interphalangeal joint 122 between the proximal intermediate link 115 and the distal intermediate link 125 of From the detected rotation angle 122α, a rotation angle 122ε around the proximal interphalangeal joint 122 between the intermediate link 121 and the distal intermediate link 125 is calculated and obtained.

Next, the control unit 1C calculates the rotation angle 122ε between the intermediate link 121 and the distal intermediate link 125, the link length of the intermediate link 121, and the link length of the distal intermediate link 125 on the intermediate link board 120. 2. The length of the virtual link 129 (line segment L2 between the shaft holes 120c and 121b) is calculated and obtained.
The control unit 1C calculates the second virtual link 129 and the middle link 121 based on the calculated length of the second virtual link 129, the link length of the middle link 121, and the link length of the distal intermediate link 125 on the intermediate link board 120. A rotation angle 132α around the distal interphalangeal joint 132 (shaft holes 121b, 131a) between the two is calculated and obtained.

Next, the control unit 1C similarly calculates the distance between the second virtual link 129 and the end link 131 from the calculated length of the second virtual link 129, the link length of the end relay link 123, and the link length of the end link 131. A rotation angle 132β around the distal interphalangeal joint 132 is calculated and obtained.

Next, the control unit 1C calculates the calculated rotation angle 132α between the second virtual link 129 and the middle joint 121, the calculated rotation angle 132β between the second virtual link 129 and the distal joint 131, and the shaft hole of the distal joint plate 131P. Between the distal link 131 that functions as a link from 131a to the shaft hole 131b on the other end side of the support plate 131S, and the fingertip link from the shaft hole 131a of the distal segment plate 131P to the tip 139e of the fingertip 139 on the other end side of the fingertip frame 131F. The rotation angle 132γ at the distal interphalangeal joint 132 between the fingertip link and the extension line 121E of the middle segment 121 (the middle segment plate 121P) is calculated and obtained from the fixed angle 133α around the shaft hole 131a.

In this way, the control unit 1C of the robot hand 1 controls the rotation angle 112α of the drive link 114 and the rotation angle of the proximal joint 111 and the middle joint 121 from the reading magnets 111rm, 114rm, 121rm and the reading heads 111rh, 114rh, 121rh. In addition to directly detecting and acquiring the rotation angles 112β and 122α (the joint angles of the metacarpophalangeal joint 112 and the proximal interphalangeal joint 122), the proximal four-bar linkage mechanism 103 can be detected without particularly installing a sensor element. The rotation angle 132γ of the fingertip 139 integrated with the distal phalanx 131 is calculated as the joint angle of the distal interphalangeal joint 132 using geometric information such as dimensions and angles of the components of the distal four-bar link mechanism 104. can be obtained. That is, in the robot hand 1, the number of sensor elements installed can be reduced to reduce costs, and the installation space can be reduced to achieve miniaturization.

The control unit 1C of the robot hand 1 executes the control program in the memory 1M and controls the forward and reverse drive of the actuator 11 based on various setting parameters and various sensor information, thereby performing various tasks under optimal conditions. Execute.
By the way, when the finger 2 is under no load when there is no workpiece W to be worked on, as shown in FIGS. 8 to 10 and FIG. The middle segment 121 is biased by the elastic force of torsion springs 141 and 142. Therefore, the proximal joint 111, the middle joint 121, and the distal joint 131 are placed in a posture in which they extend substantially linearly, and the shapes of the proximal four-bar link mechanism 103 and the distal four-bar link mechanism 104 are maintained.

Furthermore, in this robot hand 1, no load is applied to any of the proximal joint 111, the middle joint 121, and the distal joint 131, and the fingertips 139 of each finger 2A to 2C are located on the virtual vertical plane 106V (near the center of the palm surface 106). 21) and face each other at alternately adjacent positions across the virtual vertical plane 106V, the finger pad 139s of the fingertip 139 is set to be in full contact with the virtual vertical plane 106V. ing.
As a result, the robot hand 1 is configured such that the actuator 11 is driven forward and backward, and the drive link 114 is driven and rotated around the metacarpophalangeal joint 112 according to the engagement position between the worm wheel 27 and the cylindrical worm 26. Fingers 2A to 2C function. This robot hand 1 starts from a position in which the fingertips 139 of the fingers 2A to 2C are widely separated from each other, and when the fingertips 139 are moved in a direction toward each other, the proximal joint 111, the middle joint 121, and the distal joint 131 are The hand interphalangeal joint 112, the proximal interphalangeal joint 122, and the distal interphalangeal joint 132 can be appropriately bent to perform tasks such as grasping the workpiece W to be worked on.

Hereinafter, according to a second embodiment, operations when gripping workpieces W2 of various shapes will be described.
For example, when gripping a cylindrical workpiece W2 (see FIG. 46(a)), the fingers 2 operate as shown in FIGS. 22 to 25.
First, by driving the robot hand 1 while holding the work W2 to be worked on so that it is located near the center between the edges 106a and 106b of the palm surface 106, the fingers 2A to 2C are moved as shown in FIG. You will have to grasp it as a whole. In this case, while the fingers 2A to 2C are in the unloaded state shown in FIG. 20, the proximal joint 111, the middle joint 121, and the distal joint 131 are in a linearly stretched posture in the direction in which the fingertips 139 approach each other, as described above. Rotation will start as it is. Then, the fingers 2A to 2C sequentially abut the proximal joint 111, the middle joint 121, and the fingertip 139 of the distal joint 131 against the workpiece W2 located near the center of the palm surface 106, and further rotation is restricted. This will allow you to grasp it.

Note that this workpiece W2 has a cylindrical shape and the fingers 2A to 2C simultaneously move in the same way to perform the gripping operation, so the operation of the finger 2A will be explained below using the drawings.
First, the fingers 2A of the robot hand 1 move from the no-load standby state shown in FIG. 114 rotates around the metacarpophalangeal joint 112, as shown in FIG. 23, the proximal joint 111 abuts the workpiece W2 and further rotation is restricted. As it is, the finger 2A is rotated further around the metacarpophalangeal joint 112 with its drive link 114, thereby deforming the proximal four-bar linkage mechanism 103, and as shown in FIG. 24, the proximal relay link. 113 is slid toward the fingertip 139, and the intermediate link plate 120 (base intermediate link 115 and distal intermediate link 125) and intermediate link 121 resist the elastic force of the torsion spring 141 and rotate the proximal interphalangeal joint 122. rotated around the center. Then, while maintaining the shape of the distal four-bar link mechanism 104, the middle segment 121 of the finger 2A hits the workpiece W2, and further rotation is restricted. At this time, after the intermediate link plate 120 (base intermediate link 115 and distal intermediate link 125) and the intermediate link 121 are rotated to the limit around the proximal interphalangeal joint 122, the intermediate link plate 121 is rotated to the workpiece W2. As will be described later, the distal link 131 starts relative rotation against the elastic force of the torsion spring 142 along with the slide of the distal relay link 123, even before the distal link 131 hits the torsion spring 142.

In this robot hand 1, even after the middle joint 121 hits the workpiece W2, the drive link 114 and the middle link plate 120 rotate around the metacarpophalangeal joint 112 and the proximal interphalangeal joint 122. As shown in FIG. 25, as the rotation of the middle link 121 is restricted, the distal relay link 123 is slid toward the fingertip 139. Thereafter, the distal phalanx 131 of the finger 2A is rotated around the distal interphalangeal joint 132 against the elastic force of the torsion spring 142, and the distal four-bar link mechanism 104 is deformed, while the fingertip 139 By being rotated around the distal interphalangeal joint 132, the finger pad 139s of the fingertip 139 is brought into contact with the workpiece W2, and further rotation is restricted and the grasping state is maintained. Ru.

In this way, in the robot hand 1 equipped with the fingers 2A to 2C of this embodiment, the driving force of one actuator 11 moves the proximal joint 111, the middle joint 121, and the distal joint 131 into the cylindrical shape of the workpiece W2 to be worked. The workpiece W2 (cylindrical object) can be gripped in an optimal state by making the fingertips 139 of the distal joint 131 fit along the outer surface of the workpiece W2.

For example, returning to FIG. 21, when the workpiece W to be worked on is sheet-like, the workpiece W is moved so as to match the virtual vertical plane 106V near the center between the edges 106a and 106b of the palm surface 106. By holding the robot hand 1 and driving the robot hand 1, the fingers 2A to 2C move from the proximal joint 111 to the middle in the direction in which the fingertips 139 approach each other, as described above, while maintaining the unloaded posture of the fingers shown in FIG. The joint 121 and the distal joint 131 are rotated while maintaining the straight extended posture. Then, the fingers 2A to 2C are brought into a state in which the pads 139s of the fingertips 139 are in full contact with the sheet-like workpiece W located on the virtual vertical plane 106V, and further rotation is restricted and gripped. is maintained. That is, the robot hand 1 can grip the sheet-like workpiece W by sandwiching it between the fingertips 139 of the fingers 2.

Further, for example, when the workpiece W3 to be worked on grasps a conical object (see FIG. 46(b)), the fingers 2 operate as shown in FIGS. 26 to 31.
First, by driving the robot hand 1 while holding the workpiece W3 to be worked on near the center between the edges 106a and 106b of the palm surface 106, the fingers 2A to 2C are moved as shown in FIG. You will have to grasp it as a whole. In this case, while the fingers 2A to 2C are in the unloaded state shown in FIG. 20, the proximal joint 111, the middle joint 121, and the distal joint 131 are in a linearly stretched posture in the direction in which the fingertips 139 approach each other, as described above. Rotation will start as it is. Then, the fingers 2A to 2C touch the workpiece W3 located near the center of the palm surface 106 in different postures (the joint angle of the metacarpophalangeal joint 112 of each finger 2, the joint angle of the proximal interphalangeal joint 122, (with different joint angles of the distal interphalangeal joints 132), the proximal phalanx 111, the middle phalanx 121, and the fingertip 139 of the distal phalanx 131 of each finger 2 sequentially butt against each other, and further rotation is restricted. This means that you can grasp it by using

Note that this workpiece W3 has a conical shape, and the fingers 2A to 2C move in different postures to grasp it. The operating principle of rotating the end joint 131 sequentially according to the shape and fitting the fingertip 139 of the end joint 131 along the outer surface of the workpiece W is different from that for the workpiece W2 (cylindrical object, see FIG. 46(a)). Since there is no such thing, the explanation will be omitted.

In the second embodiment of the present invention, as described above, the drive force of the actuator 11 is transmitted to the drive link 114 (drive link plate 114P) through different routes through the fingers 2A, 2B, and 2C. There is. In addition, since the differential device 41 is interposed in the drive transmission path between the fingers 2B and 2C, the rotation angle [112α] of the drive link 114 (drive link plate 114P) that drives each finger is different, and the work can be performed. It is configured to be executable. Therefore, as shown by broken lines in FIGS. 27 to 31, the driving links (114A, 114B, 114C) of each finger take different postures, and the fingers 2A to 2C operate in different postures to grip the workpiece W3. be able to.

This will be explained in more detail with reference to FIGS. 26 to 31, which show the postures of the conical workpiece W3 (object W3) in a gripped state.
FIG. 26 is a perspective view thereof, and FIG. 27 is a side view thereof. FIG. 28 is a side view showing the gripping state of the conical workpiece W3 (object W3) as seen from the opposite direction to FIG. 27. FIG. 29 to 31 are side views in which only the object is drawn in cross section at the part where the front finger (2B) and the workpiece W3 (object W3) touch in the side view shown in FIG. 28, and the center finger (2A) and This is a side view in which only the cross section of the object is drawn at the part where the workpiece W3 (object W3) contacts, and a side view in which only the cross section of the object is drawn at the part where the back finger (2C) and the workpiece W3 (object W3) are in contact. .

In FIG. 29, the proximal joint 111B of the front finger (2B) contacts the conical workpiece W3 (object W3), the following middle joint 121B contacts the conical workpiece W3 (object W3), and the following fingertip 139B is a side view showing the posture when the conical workpiece W3 (target object W3) is brought into contact with the conical workpiece W3 and gripping is completed. FIG. As shown in FIG. 29, the finger (2B) in the front has its proximal joint 111B, middle joint 121B, and distal joint 131B (fingertip 139B) along the outer surface of the thick diameter part near one end of the workpiece W3. As a result, the workpiece W3 (cone-shaped object, see FIG. 46(b)) can be gripped in an optimal state.

Further, in FIG. 30, the proximal joint 111A of the central finger (2A) contacts the conical workpiece W3 (object W3), and the following middle joint 121A contacts the conical workpiece W3 (object W3), FIG. 13 is a side view showing a posture when a subsequent fingertip 139A contacts a conical workpiece W3 (object W3) and gripping is completed. As shown in FIG. 30, also in the middle finger (2A), its proximal joint 111A, middle joint 121A, and terminal joint 131A (fingertip 139A) fit into the outer surface of the medium-thick part near the middle of the workpiece W3. The workpiece W3 (cone-shaped object, see FIG. 46(b)) can be gripped in an optimal state by aligning the workpiece W3 in the same manner as shown in FIG.

In addition, FIG. 31 shows that the proximal joint 111C of the back finger (2C) contacts the conical workpiece W3 (object W3), and the following middle joint 121C contacts the conical workpiece W3 (object W3). , is a side view showing the posture when the subsequent fingertip 139C comes into contact with the conical workpiece W3 (object W3) and gripping is completed. As shown in the figure, the back finger (2C) is also made to fit its proximal joint 111C, middle joint 121C, and terminal joint 131C (fingertip 139C) along the outer surface of the narrow diameter part near the other end of the workpiece W3. , the workpiece W3 (cone-shaped object, see FIG. 46(b)) can be gripped in an optimal state.

In this way, in the robot hand 1 equipped with the fingers 2A to 2C of this embodiment, the driving force of one actuator 11 is transmitted to each finger 2, and the drive force is transmitted to the drive transmission path between the fingers 2B and 2C. By interposing the differential device 41, the proximal joint 111, the middle joint 121, and the distal joint 131 of each finger can be shaped into the shape of the workpiece W3 to be worked with which each finger comes into contact, even for a workpiece W having a conical shape. The workpiece W3 (cone-shaped object, see FIG. 46(b)) can be rotated sequentially according to the direction of the workpiece W3 (cone-shaped object, see FIG. 46(b)) by making the fingertip 139 of the distal phalanx 131 of each finger fit along the outer surface of the workpiece W3. It can be held in any condition.

Note that when the actuator 11 is driven to release the gripped workpiece W, the nodes move away from the workpiece in the opposite order to the order in which the nodes fit into the outer surface of the workpiece W when gripped. Specifically, first the fingertip 139 (distal joint 131) separates from the workpiece W, then the middle joint 121 separates from the workpiece W, finally the base joint 111 separates from the workpiece W, and then the base joint 111, the middle joint 121, and the terminal joint Rotation is started while maintaining the linear stretching posture of 131.

When gripping a workpiece W3 (cone-shaped object, see FIG. 46(b)) or the like, and releasing the workpiece W gripped by the fingers 2A to 2C in different postures, the postures of the fingers 2A to 2C in the linear stretching posture are Sometimes it works without matching. For example, even though the finger 2B in the linearly stretched posture is far from the finger 2A in the linearly stretched posture, the finger 2C in the linearly stretched posture is close to the finger 2A in the linearly stretched posture. It can be a posture. Even in such a case, by driving the actuator 11 in a direction in which the fingers 2A and 2B (2C) move away from each other (the fingers open), a configuration is adopted in which the postures of the fingers 2 in the linearly stretched posture are aligned. There is.

Specifically, as shown in FIG. 16, the drive link 114 is provided with an abutment surface 114t1 that functions as a stopper to limit excessive rotation. This abutment surface 114t1 is formed in a substantially square shape on the outside of the proximal four-bar link mechanism 103 on the side that is slightly separated from the shaft hole 114a (axis of the metacarpophalangeal joint 112) of the drive link plate 114P, so that it faces It functions to limit reverse rotation by hitting the side. Further, as shown in FIGS. 8, 22, and 26, the abutment surface 106t1 is an abutment surface of the drive link plate 114P on the surface of the palm 106 that is slightly separated from the axis of the metacarpophalangeal joint 112. It is formed on the opposing surface facing 114t1, and functions to abut against the abutting surface 114t1 and limit its reverse rotation.

If the abutting surface 114t1B of the finger 2B and the abutting surface 106t1B abut before the abutting surface 114t1C of the finger 2C and the abutting surface 106t1C, the rotation of the side shaft 51 of the differential gear 41 Movement stops. Since the rotational movement of the side shaft 51 is stopped, the driving of the finger 2B is also stopped. Further, since the rotational movement of the side shaft 51 has stopped, the side shaft 61 rotates at twice the speed of the rotational movement of the differential case 42, and the abutment surface 114t1C of the finger 2C and the abutment surface 106t1C When it hits, the drive of the finger 2C also stops.
Simultaneously with this stop, the abutment surface 114t1A of the finger 2A and the abutment surface 106t1A also come into contact, and the drive of the finger 2A also stops.

On the contrary, if the abutting surface 114t1C of the finger 2C and the abutting surface 106t1C occur before the abutting surface 114t1B of the finger 2B and the abutting surface 106t1B, the side of the differential gear 41 The rotational movement of the shaft 61 stops. Since the rotational movement of the side shaft 61 is stopped, the driving of the finger 2C is also stopped. Further, since the rotational movement of the side shaft 61 has stopped, the side shaft 51 rotates at twice the speed of the rotational movement of the differential case 42, and the abutment surface 114t1B of the finger 2B and the abutment surface 106t1B When it hits, the drive of the finger 2B also stops.
Simultaneously with this stop, the abutment surface 114t1A of the finger 2A and the abutment surface 106t1A also come into contact, and the drive of the finger 2A also stops.
With such a configuration, even when releasing the workpiece W and gripping it again, the fingers 2 can resume gripping from a linearly stretched posture as shown in FIG. 20.

In the robot hand 1 of the second embodiment, as shown in FIGS. 9 to 11, the driving force of one actuator 11 is applied to drive links 114 (114A, 114B, 114C) that drive fingers 2 (2A, 2B, 2C). The cylindrical worm 26 (26A, 26B, 26C) and the worm wheel 27 (27A, 27B, 27C) are used in the path for transmitting the drive force to the point (26A, 26B, 26C). The cylindrical worm 26 (26A, 26B, 26C) and the worm wheel 27 (27A, 27B, 27C) constitute a transmission device 25 (25A, 25B, 25C) with a self-locking mechanism. As explained in the self-locking transmission device 21 (21A, 21B) of the first embodiment, this self-locking transmission device can transmit driving force from the input side to the output shaft, but external forces acting on the output shaft It has a function that prevents load force from being transmitted to the input shaft.
In the second embodiment, a transmission device 25 with a self-locking mechanism is used, which is composed of a cylindrical worm 26 and a worm wheel 27, but it is different from the transmission device 25 with a self-locking mechanism, which is composed of a screw shaft 22 and a screw nut 23, which are used in the first embodiment. A configuration in which the transmission device 21 with a self-locking mechanism is used in the second embodiment may also be used.

When the object W (W2, W3) is gripped by the robot hand 1 and the object W is conveyed at high speed (a task in which the object W is suddenly decelerated at the target position), there is an inertial force on the object W when it stops. This inertial force acts as an external force on the robot hand 1. In addition, even when grasping an object with an indefinite center of gravity position (for example, an object containing liquid and air in a container whose center of gravity changes as the liquid moves) or a moving object (for example, an animal), the center of gravity An external force due to the positional movement acts on the robot hand 1.
In the second embodiment, since the self-locking transmission devices 25B and 25C are provided on the output side (the side where the finger 2 is located) of the differential device 41, even if an external force is applied to the robot hand 1, the side shaft will not move. No differential movement occurs between the fingers 51 and 61, and reliable gripping is achieved with the fingers 2B and 2C. Further, by providing the transmission device 25A with a self-locking mechanism, even if an external force is applied to the robot hand 1, a reliable grip can be achieved with the fingers 2A.

In addition, as explained in FIG. 11, the control unit 1C of the robot hand 1 moves the drive link plate 114P from the reference position R at the finger 2 based on the rotation information of the reading magnet 114rm detected by the reading head 114rh. Based on the rotation angle 112α around the hand interphalangeal joint 112 (shaft holes 111a, 114a) and the rotation information of the reading magnet 111rm detected by the reading head 111rh, the metacarpal finger of the proximal phalanx plate 111P is rotated from the reference position R of the finger 2. Based on the rotation angle 112β around the interphalangeal joint 112 and the rotation information of the reading magnet 121rm detected by the reading head 121rh, the proximal interphalangeal joint 122 (shaft holes 111b, 121a) of the middle phalangeal plate 121P with respect to the proximal phalangeal plate 111P is determined. ) is directly acquired, and the rotation angle 132γ around the distal interphalangeal joint 132 (shaft holes 121b, 131a) of the distal phalanx plate 131P relative to the middle phalanx plate 121P is calculated and acquired.
Further, the control unit 1C uses the acquired rotation angle information and geometric information such as the dimensions and angles of the constituent elements of the proximal four-bar link mechanism 103 and the distal four-bar link mechanism 104, The posture of finger 2 (2A, 2B, 2C) is acquired.
In addition, the control unit 1C determines the gripping status of the workpiece based on the detected and acquired posture of each finger 2 (2A, 2B, 2C).

Specifically, if the posture of each finger 2 (2A, 2B, 2C) does not change even though the actuator 11 is driven by a command from the control unit 1C, "possibility of grasping the object" is detected. It has been determined that "Yes." The grasping status of the workpiece W is determined by comparing and referencing the grasped object information (the shape of the workpiece W, the assumed posture of the fingers 2 when the workpiece W is grasped as expected) set in advance in the memory 1M and the obtained information. ing.
For example, when a command from the control unit 1C is used to grasp a workpiece W3 (a cone-shaped object), each finger 2 (2A, 2A, 2B, 2C) are stored. Then, the detected and acquired posture of each finger 2 (2A, 2B, 2C) is compared with the assumed posture preset in the memory 1M, and if the comparison results match, the control section 1C controls the workpiece W3 (cone-shaped object). ) (is being held in the situation shown in FIG. 26).
If the comparison results do not match, the control unit 1C determines that the workpiece W3 (cone-shaped object) is not gripped (the gripping situation shown in FIG. 22 is not the gripping situation shown in FIG. 26), and stops the gripping operation. Start over.

In addition, the control unit 1C of the robot hand 1 of the second embodiment is connected to an encoder 11E that detects the rotation angle of the drive output shaft of the actuator 11, as shown in FIG. The drive link plates 114P (114PA, 114PB, 114PC) are obtained based on the information of the encoder 11E and the rotation information of the reading magnets 114rm (114rmA, 114rmB, 114rmC) detected by the reading heads 114rh (114rhA, 114rhB, 114rhC). The system verification of the drive mechanism of the robot hand 1 is performed based on the information of the rotation angle 112α (112αA, 112αB, 112αC) around the metacarpophalangeal joints 112 (112A, 112B, 112C).

Specifically, the control unit 1C controls the reduction ratio of the transmission device 11T, the reduction ratio of the belt transmission mechanism composed of the drive pulley 31P, the transmission belt 32, and the driven pulley 33P, the drive gear 34G, and the drive gear 34G based on the information from the encoder 11E. The rotation angle of the differential case 42 is detected in consideration of the reduction ratio of the gear transmission mechanism constituted by the transmission gear 36G. For convenience of explanation, this detection angle is defined as 42r1.
The control unit 1C automatically controls the rotation angle 112αA of the drive link plate 114PA around the metacarpophalangeal joint 112A, which is acquired based on the rotation information of the reading magnet 114rmA detected by the reading head 114rhA of the finger 2A. The rotation angle of the differential case 42 is detected in consideration of the reduction ratio of the transmission device with lock mechanism 25A and the reduction ratio of the gear transmission mechanism composed of the drive gear 34G and the transmission gear 36G. For convenience of explanation, this detection angle is defined as 42r2.

The control unit 1C also controls the rotation angle 112αB of the drive link plate 114PB around the metacarpophalangeal joint 112B, which is obtained based on the rotation information of the reading magnet 114rmB detected by the reading head 114rhB of the finger 2B. The rotation angle of the side gear 51 is detected in consideration of the reduction ratio of the self-locking transmission device 25B and the reduction ratio of the belt transmission mechanism composed of the drive pulley 51P, the transmission belt 52, and the driven pulley 53P. For convenience of explanation, this detection angle is defined as 51r3.

Further, the control unit 1C controls the rotation angle 112αC of the drive link plate 114PC around the metacarpophalangeal joint 112C, which is acquired based on the rotation information of the reading magnet 114rmC detected by the reading head 114rhC of the finger 2C. The rotation angle of the side gear 61 is detected in consideration of the reduction ratio of the self-locking transmission device 25C and the reduction ratio of the belt transmission mechanism composed of the drive pulley 61P, the transmission belt 62, and the driven pulley 63P. For convenience of explanation, this detection angle is defined as 61r3.

Further, the control unit 1C calculates the average value as shown in equation (2) based on the detected rotation angle 51r3 of the side gear 51 and the detected rotation angle 61r3 of the side gear 61, and detects the rotation angle of the differential case 42. ing. For convenience of explanation, this detection angle is defined as 42r3.
Rotation angle 42r3 of differential case 42
=(Rotation angle of side shaft 51 + rotation angle of side shaft 61)÷2...(2)

The control unit 1C compares the values of the rotation angles (42r1, 42r2, 42r3) of the differential case 42 detected by the three methods, and if they are all equal based on the allowable error (sensor resolution and sensor detection accuracy error), the robot hand It is determined that the drive mechanism system of No. 1 is operating normally.
However, if the values of the rotation angles (42r1, 42r2, 42r3) of the differential case 42 detected by the three methods are compared and they are not equal even after considering the allowable error (sensor resolution and sensor detection accuracy error), the robot hand 1 It is determined that the drive mechanism system is not operating properly.

For example, if the value of 42r2 and the value of 42r3 are equal and only the value of 42r1 is different, it may be due to backlash in the transmission device 11T or tooth skipping due to gear tooth wear, or belt transmission by the drive pulley 31P, transmission belt 32, and driven pulley 33P. It is determined that the drive mechanism system of the robot hand 1 is not operating normally due to belt elongation or step-out of the mechanism, loosening of the rotation angle sensor (11E), or failure.
For example, if the values of 42r1 and 42r3 are the same and only the value of 42r2 is different, there may be looseness in the self-locking transmission device 25A, tooth skipping due to gear tooth wear, or installation of the rotation angle sensor (114rhA, 114rmA). It is determined that the drive mechanism system of the robot hand 1 is not operating normally due to loosening or failure.

On the other hand, if the value of 42r1 is equal to the value of 42r2 and only the value of 42r3 is different, the self-locking transmission devices 25B, 25C, the differential device 41, the gear consisting of the driving gear 34G and the driven gear 36G Play in the transmission device, play in gear tooth wear, tooth skipping due to gear friction wear, belt elongation or out of alignment in the belt transmission mechanism between the drive pulley 51P, transmission belt 52 and driven pulley 53P, drive pulley 61P, transmission belt 62 and driven pulley. If the drive mechanism system of the robot hand 1 is not operating normally due to belt elongation or loss of synchronization of the belt transmission mechanism due to 63P, or loosening or failure of the rotation angle sensor (114rhB, 114rmB, 114rhC, 114rmC), etc. to decide.

In addition, as explained in FIG. 11, the control unit 1C of the robot hand 1 moves the proximal plate 111P from the reference position R of the finger 2 based on the rotation information of the reading magnet 111rm detected by the reading head 111rh. The proximal interphalangeal joint 122 (shaft hole 111b, 121a) is directly acquired, and the rotation angle 132γ around the distal interphalangeal joint 132 (shaft holes 121b, 131a) of the distal phalanx plate 131P relative to the middle phalanx plate 121P is calculated and acquired. That is, the joint angles of the metacarpophalangeal joint 112, the proximal interphalangeal joint 122, and the distal interphalangeal joint 132 of the finger 2, which has a plurality of joints, are acquired.
Backlash in the proximal four-bar link mechanism 103 that constitutes the finger 2, play in the distal four-bar link mechanism 104, rotation angle sensor (111rhA, 111rmA, 121rhA, 121rmA, 111rhB, 111rmB, 121rhB, 121rmB, 111rhC, 111rmC, 121rhC , 121rmC) becomes loose or malfunctions, each finger 2( 2A, 2B, 2C) and the assumed posture preset in the memory 1M no longer match.
Even in such a case, the control unit 1C determines that the drive mechanism system of the robot hand 1 is not operating normally.

[Example 3]
32 to 34 are diagrams showing the robot hand 1 based on the third embodiment. The differential device 41' used is different from the second embodiment.
Specifically, the differential device 41' used in the third embodiment has torsion springs 46 and 47 added to the configuration of the differential device 41 in the second embodiment, and has the same structure as the differential device 41 in the second embodiment. It has restrictions on movement.
When the robot hand 1 of this embodiment 3 performs a work of grasping a workpiece W, the proximal joint 111, the middle joint 121, and the distal joint 131 of the finger 2 are sequentially rotated according to the shape of the workpiece W to be worked, and the distal joint The point that the gripping operation of the workpiece W up to the fingertips 139 of the workpiece 131 is adapted to the outer surface of the workpiece W, and the operation principle and operation behavior thereof are the same as those of the second embodiment, and therefore the description thereof will be omitted.

In the differential device 41' used in the third embodiment, the relative posture of the side shafts 51, 61 with respect to the differential case 42 is an initial posture (a posture when no load is applied to both side shafts 51, 61, which will be described later). ) is configured to be maintained.
Specifically, as shown in FIGS. 32 to 34, torsion springs 46 and 47 are installed around side shafts 51 and 61, respectively. Further, the torsion spring 46 has one end fixed to the differential case 42 and the other end fixed to the side shaft 51. Further, the torsion spring 47 has one end fixed to the differential case 42 and the other end fixed to the side shaft 61. That is, the torsion springs 46 and 47 are arranged so that the amount of torsion changes depending on the difference in relative motion between the differential case 42 and the side shafts 51 and 61.

Further, when no load is applied to both differential shafts 51 and 61, the torsion springs 46 and 47 are configured to maintain a posture (initial posture) in which the forces of each other to return to their natural states are balanced. .
With such a configuration, the differential device 41' of the third embodiment generates differential motion between the side shaft 51 and the side shaft 61, but limits the differential motion, and the differential case The relative postures of the side shafts 51 and 61 with respect to 42 are maintained at the initial posture.

By using the differential device 41' that limits the differential operation of the differential device 41, the behavior when releasing the workpiece W is partially different from the behavior in the second embodiment.
That is, as in the second embodiment, when the actuator 11 is driven to release the gripped workpiece W, the nodes move away from the workpiece contrary to the order in which the nodes fit into the outer surface of the workpiece W when gripped. Also, first the fingertip 139 (end joint 131) separates from the work W, then the middle joint 121 leaves the work W, finally the base joint 111 leaves the work W, and then the straight line between the base joint 111, the middle joint 121, and the end joint 131 The same is true for the fact that the rotation is started in the stretched position.
However, this embodiment differs from the second embodiment in the timing at which the fingers 2A, 2B, and 2C are all aligned in a linearly stretched posture.

In Embodiment 2, as described above, when the abutment surfaces 114t1 (114t1A, 114t1B, 114t1C) of each finger 2 (2A, 2B, 2C) and the abutment surfaces 106t1 (106t1A, 106t1B, 106t1C) all abut against each other. Then, the fingers 2A, 2B, and 2C are all aligned in a linearly stretched posture.
On the other hand, in Embodiment 3, by using the differential device 41' that limits the differential operation of the differential device 41, when the joints of all the fingers 2 are separated from the work W, the finger The fingers 2A, fingers 2B, and fingers 2C are all aligned in a straight, stretched posture. Even after they are aligned, if the actuator 11 is further driven so that the fingers 2 are opened, the rotation of the proximal joint 111, the middle joint 121, and the distal joint 131 continues in the linearly extended posture. The abutment surfaces 114t1 (114t1A, 114t1B, 114t1C) of each finger 2 (2A, 2B, 2C) and the abutment surface 106t1 (106t1A, 106t1B, 106t1C) occur simultaneously, and the abutment surfaces of the fingers 2 (2A, 2B, 2C) occur simultaneously. The drive also stops.

Similarly to the second embodiment, in the robot hand 1 of the third embodiment, the driving force of one actuator 11 is applied to drive links 114 (114A, 114B, 114C) that drive the fingers 2 (2A, 2B, 2C). Cylindrical worms 26 (26A, 26B, 26C) and worm wheels 27 (27A, 27B, 27C) are used for the transmission path. The cylindrical worm 26 (26A, 26B, 26C) and the worm wheel 27 (27A, 27B, 27C) constitute a transmission device 25 (25A, 25B, 25C) with a self-locking mechanism.
As described above, in the third embodiment, as in the second embodiment, the robot hand 1 Even if an external force is applied to the side shafts 51 and 61, no differential movement occurs in the side shafts 51 and 61, and a reliable grip is achieved with the fingers 2B and 2C. Further, by providing the transmission device 25A with a self-locking mechanism, even if an external force is applied to the robot hand 1, a reliable grip can be achieved with the fingers 2A.
Note that the determination of the gripping state of the workpiece W and the system verification of the drive mechanism in the third embodiment are also the same as in the second embodiment, and the description thereof will be omitted.

As described above, the drive mechanism of the third embodiment has three fingers (2A, 2B, 2C) and grips the article by transmitting the drive force of the actuator 11. The drive mechanism includes a differential device 41 that distributes the drive force transmitted from the actuator 11, and has a drive force transmission device that connects the actuator 11 and each finger. The three fingers are a first finger (2A) placed in the center on one end side of the palm surface (106) of the main body of the robot hand 1, and a second finger placed at a distance on the other end side of the palm surface. (2B) and the third finger (2C). The differential device 41 includes a case (differential case 42) to which the driving force of the actuator 11 is transmitted, and a second finger-side shaft (side shaft 51) that is provided at one end of the case and transmits the driving force to the second finger. and a third finger side shaft (side shaft 61) that is provided on the other end side of the case and transmits the driving force to the third finger. Furthermore, the differential device 41 includes a first torsion spring (46) having one end fixed to the case and the other end fixed to the second finger side shaft, and a first torsion spring (46) having one end fixed to the case and the other end fixed to the third finger side shaft. A second torsion spring (47) fixed to the shaft. Therefore, according to the drive mechanism of the third embodiment, the elastic force of the torsion springs on both sides acts on the differential movement between the second finger-side shaft and the third finger-side shaft, so that the robot hand 1 Three fingers can be moved according to the shape of the object. In other words, with only one actuator, it is possible to realize finger and joint movements suitable for the shape of objects with different diameters, and also to realize movement of fingers and joints suitable for the shape of objects with different diameters. Even if an external force is generated, it is possible to maintain stable gripping of the object without changing the gripping position.

[Example 4]
35 to 43 are diagrams showing a robot hand 1 based on Example 4 of the present invention. When comparing Example 4 and Example 2, the difference is that a plurality of differential devices are provided. In the second embodiment, one differential device, the differential device 41, is used, whereas in the fourth embodiment, two differential devices, the differential device 41 and the differential device 71, are used.
The differential device 41 and the differential device 71 used in the fourth embodiment and the differential device 41 used in the second embodiment have almost the same configuration, although there are differences in the lengths of the side shafts 51 and 61. The explanation regarding the differential devices 41 and 71 will be omitted.

Also, in the robot hand 1 of the fourth embodiment, when performing the work of gripping the workpiece W, the proximal joint 111, the middle joint 121, and the distal joint 131 of the finger 2 are sequentially rotated according to the shape of the workpiece W to be worked on. , the point that the gripping operation of the distal joint 131 up to the fingertip 139 is realized so that it fits the outer surface of the workpiece W, and the operation principle and operation behavior thereof are the same as in the second embodiment, and the explanation will be omitted.
As shown in FIGS. 35 to 37, the configuration of the fourth embodiment is such that a differential device 71 is interposed in a path through which the driving force of the actuator 11 is transmitted to the transmission shaft 157 and the differential device 41. .

Further, in the fourth embodiment, the number of differential devices employed is 2 (devices), which is one less than the number of fingers 2 driven by one actuator 11 (3).
By adopting such a configuration, the differential device 71 is interposed in the drive transmission path of the finger 2A, and the differential devices 41 and 71 are interposed in the drive transmission path of the fingers 2B and 2C, so that each finger The structure is such that work can be performed while rotating the rotation angle [112α] of the drive link 114 (drive link plate 114P) that drives the drive link 114 (drive link plate 114P) completely independently of the output rotation angle of the actuator 11.
That is, the rotation angle [112α] of the drive link 114 (drive link plate 114P) that drives each finger is uniquely determined as a function of the output rotation angle of the actuator 11 for all fingers 2 (2A, 2B, 2C). I try not to get caught.

The fourth embodiment will be described below, focusing on the differences compared to the drive transmission path of the second embodiment.
The actuator 11 outputs driving force by rotating a transmission shaft 31 via a transmission device 11T that includes a built-in planetary gear and has functions such as deceleration. A drive gear 31G is fixed so as to rotate together on the same axis. The driven gear 33G is rotatably supported inside the palm 105 so as to be disposed at a position where it meshes with the driving gear 31G and rotated by the driven gear.
The driven gear 33G is fixed so that the differential case 72 rotates coaxially with the differential case 72 so as to function as a ring gear that constitutes the differential device 71. Thereby, the driving force of the actuator 11 is transmitted to the differential case 72.

The differential device 71 includes a differential case 72, a pinion gear (not shown) disposed inside the differential case 72, side gears (also not shown), and side shafts 81, 91. Further, the differential device 71 is fixed and free in the axial direction inside the palm 105 with respect to the not-illustrated frame of the robot hand 1 so that it is driven and rotated when the driving force of the actuator 11 is transmitted. Rotatably supported.
A drive gear 81G is fixed to the tip of the side shaft 81 so as to rotate together on the same axis. The driven gear 83G is disposed at a position where it meshes with the driving gear 81G and is rotatably supported inside the palm 105 so as to be rotated by the driven gear, and the driven gear 83G is rotated integrally with the transmission shaft 157 coaxially with the driven gear 83G. It is fixed as follows.
A cylindrical worm 26A is fixed to the opposite end of the transmission shaft 157 so as to coaxially rotate therewith. This cylindrical worm 26A is engaged with a worm wheel 27A of a drive link plate 114PA, in which a connecting shaft 114SA is inserted into a shaft hole 114aA at one end, so that the cylindrical worm 26A is rotated forward and backward.

As a result, in the metacarpophalangeal joint 112A of the finger 2A, the driving force of the actuator 11 is transmitted to the gear transmission mechanism consisting of the driving gear 31G and the driven gear 33G, and the transmitted driving force is transmitted to the differential gear 71. The driving force is transmitted to the side shaft 81, and the transmitted driving force is transmitted to the transmission shaft 157 through a gear transmission mechanism consisting of a driving gear 81G and a driven gear 83G, and further through a cylindrical worm 26A and a worm wheel 27A. The deceleration is transmitted and the drive link plate 114PA is rotated in forward and reverse directions.
That is, regarding the drive of the finger 2A, the transmission shafts 31 and 157, the cylindrical worm 26A, the worm wheel 27A, the drive gears 31G and 81G, the driven gears 33G and 83G, the differential device 71, and the side shaft 81 receive the driving force of the actuator 11. It constitutes a driving force transmission device that transmits.

A drive gear 91G is fixed to the tip of the side shaft 91 so as to coaxially rotate therewith. The intermediate gear 92G is rotatably supported inside the palm 105 so as to be disposed at a position where it meshes with the drive gear 91G and the driven gear 93G, and to be rotated by the drive gear 91G and the driven gear 93G. A driven gear 93G that meshes with the intermediate gear 92 is rotatably supported inside the palm 105 so as to be rotated by the driving gear 91G. are fixed so that they rotate together on the same axis.
The drive transmission path from the side shafts 51, 61 of the differential device 41 to the drive links 114B, 114C (drive link plates 114PB, 114PC) that drive the fingers 2B, 2C is the same as in the second embodiment.

As a result, in the metacarpophalangeal joint 112B of the finger 2B, the driving force of the actuator 11 is transmitted to the gear transmission mechanism consisting of the driving gear 31G and the driven gear 33G, and the transmitted driving force is transmitted to the differential gear 71. The driving force is transmitted to the side shaft 91, and the transmitted driving force is transmitted to the side shaft 51 of the differential gear 41 via a gear transmission mechanism including a driving gear 91G, an intermediate gear 92G, and a driven gear 93G. The transmitted driving force is transmitted to the transmission shaft 177 via a belt transmission mechanism consisting of a drive pulley 51P, a transmission belt 52, and a driven pulley 53P, and is further decelerated and transmitted via a cylindrical worm 26B and a worm wheel 27B to drive. Link plate 114PB is rotated forward and backward.
That is, regarding the drive of the finger 2B, the transmission shafts 31, 177, the cylindrical worm 26B, the worm wheel 27B, the driving pulley 51P, the driven pulley 53P, the transmission belt 52, the driving gears 31G, 91G, the driven gears 33G, 93G, and the intermediate gear 92G. , the differential devices 41 and 71 and the side shafts 51 and 91 constitute a driving force transmission device that transmits the driving force of the actuator 11.

Further, in the metacarpophalangeal joint 112C of the finger 2C, the driving force of the actuator 11 is transmitted to a gear transmission mechanism consisting of a driving gear 31G and a driven gear 33G, and the transmitted driving force is transmitted to the side of the differential device 71. The driving force is transmitted to the shaft 91, and the transmitted driving force is transmitted to the side shaft 61 of the differential device 41 via a gear transmission mechanism consisting of a driving gear 91G, an intermediate gear 92G, and a driven gear 93G. The driving force is transmitted to the transmission shaft 187 via a belt transmission mechanism consisting of a drive pulley 61P, a transmission belt 62, and a driven pulley 63P, and is further decelerated and transmitted via a cylindrical worm 26C and a worm wheel 27C to a drive link. Plate 114PC is rotated forward and backward.
That is, regarding the drive of the finger 2C, the transmission shaft 31, 187, the cylindrical worm 26C, the worm wheel 27C, the driving pulley 61P, the driven pulley 63P, the transmission belt 62, the driving gears 31G, 91G, the driven gears 33G, 93G, and the intermediate gear 92G. , the differential devices 41 and 71 and the side shafts 61 and 91 constitute a driving force transmission device that transmits the driving force of the actuator 11.

Accordingly, in the fourth embodiment, the actuator 11 is driven in the forward and reverse directions, and the drive link 114 is driven around the metacarpophalangeal joint 112 according to the meshing position between the worm wheel 27 and the cylindrical worm 26. The fingers 2A to 2C function by being rotated. This robot hand 1 starts from a position in which the fingertips 139 of the fingers 2A to 2C are widely separated from each other, and when the fingertips 139 are moved in a direction toward each other, the proximal joint 111, the middle joint 121, and the distal joint 131 are The hand interphalangeal joint 112, the proximal interphalangeal joint 122, and the distal interphalangeal joint 132 can be appropriately bent to perform tasks such as grasping the workpiece W to be worked on.

Further, for example, when the fingers 2 grip an object whose workpiece W4 has a different diameter (see FIG. 46(c)), the fingers 2 operate as shown in FIGS. 38 to 43.
First, by driving the robot hand 1 while holding the workpiece W4 to be worked on near the center between the edges 106a and 106b of the palm surface 106, the fingers 2A to 2C are moved as shown in FIG. You will have to grasp it as a whole. In this case, while the fingers 2A to 2C are in the unloaded state shown in FIG. 20, the proximal joint 111, the middle joint 121, and the distal joint 131 are in a linearly stretched posture in the direction in which the fingertips 139 approach each other, as described above. Rotation will start as it is. Then, the fingers 2A to 2C touch the workpiece W4 located near the center of the palm surface 106 in different postures (the joint angle of the metacarpophalangeal joint 112 of each finger 2, the joint angle of the proximal interphalangeal joint 122, (with different joint angles of the distal interphalangeal joints 132), the proximal phalanx 111, the middle phalanx 121, and the fingertip 139 of the distal phalanx 131 of each finger 2 sequentially butt against each other, and further rotation is restricted. This means that you can grasp it by using
Note that this workpiece W4 has a different diameter shape and the fingers 2A to 2C operate in different postures to grasp it, but the proximal joint 111, middle joint 121, and distal joint 131 of the finger 2 are used as the workpiece W4 to be worked on. Regarding the operating principle of rotating the workpiece W2 (cylindrical object, see Fig. 46(a)) sequentially according to the shape of the workpiece W2 (cylindrical object), the workpiece W2 (cylindrical object) can be rotated sequentially according to the shape of the workpiece W2, so that the fingertip 139 of the distal joint 131 can fit along the outer surface of the workpiece W. ) and the workpiece W3 (cone-shaped object, see FIG. 46(b)), so the explanation will be omitted.

In the fourth embodiment of the present invention, as described above, the drive force of the actuator 11 is transmitted to the drive link 114 (drive link plate 114P) through different routes through the fingers 2A, 2B, and 2C. There is. Further, since a differential device 71 is interposed in the drive transmission path of the finger 2A, and differential devices 41 and 71 are interposed in the drive transmission path of the fingers 2B and 2C, the drive link 114 that drives each finger The structure is such that work can be performed while driving the rotation angle [112α] of the drive link plate 114P completely independently of the output rotation angle of the actuator 11. Therefore, as shown by broken lines in FIGS. 39 to 43, the driving links (114A, 114B, 114C) of each finger take different postures, and the fingers 2A to 2C operate in different postures to grip the workpiece W4. be able to.

This will be explained in more detail with reference to FIGS. 38 to 43, which are diagrams showing the postures of the gripped workpiece W4 (object W4) having a different diameter shape.
FIG. 38 is a perspective view thereof, FIG. 39 is a side view thereof, and FIG. 40 is a side view showing the posture of a workpiece W4 (target object W4) having a different diameter shape when viewed from the opposite direction to that in FIG. 39. .
In addition, FIGS. 41 to 43 are a side view in which only the object is drawn in cross section at the part where the front finger (2B) and the workpiece W4 (object W4) touch, and a side view of the center finger in the side view shown in FIG. (2A) A side view in which only the object is drawn in cross section at the part where it touches the workpiece W4 (object W4), a cross-section drawing in which only the object is drawn at the part where the finger in the back (2C) and the workpiece W4 (object W4) touch. FIG.

In FIG. 41, the proximal joint 111B of the front finger (2B) contacts a workpiece W4 (object W4) with a different diameter shape, and the following middle joint 121B contacts a workpiece W4 (object W4) with a different diameter shape, FIG. 13 is a side view showing a posture when the subsequent fingertip 139B comes into contact with a workpiece W4 (object W4) having a different diameter shape and gripping is completed.
As shown in FIG. 41, the finger (2B) at the front has its proximal joint 111B, middle joint 121B, and distal joint 131B (fingertip 139B) along the outer surface of the thick diameter part near one end of the workpiece W4. As a result, the workpiece W4 (object having a different diameter shape, see FIG. 46(c)) can be gripped in an optimal state.

Further, in FIG. 42, the proximal joint 111A of the central finger (2A) contacts the workpiece W4 (object W4) with a different diameter shape, and the following middle joint 121A contacts the workpiece W4 (object W4) with a different diameter shape. 139A is a side view showing the posture when the subsequent fingertip 139A comes into contact with a workpiece W4 (target object W4) having a different diameter shape and gripping is completed. FIG. As shown in FIG. 42, the center finger (2A) also has its proximal joint 111A, middle joint 121A, and terminal joint 131A (fingertip 139A) that fit into the outer surface of the constricted and narrowest part near the middle of the workpiece W4. The workpiece W4 (object having a different diameter shape, see FIG. 46(c)) can be gripped in an optimal state by making the workpiece W4 lie along the handlebar.

In addition, in FIG. 43, the proximal joint 111C of the back finger (2C) contacts the workpiece W4 (object W4) with a different diameter shape, and the following middle joint 121C contacts the workpiece W4 (object W4) with a different diameter shape. FIG. 13 is a side view showing the posture when the fingertips 139C that continue to contact and grip a workpiece W4 (target object W4) having a different diameter shape are completed. As shown in FIG. 43, for the finger at the back (2C), its base joint 111C, middle joint 121C, and end joint 131C (fingertip 139C) are arranged so that they fit into the outer surface of the narrow diameter part near the other end of the workpiece W4. The workpiece W4 (object having a different diameter shape, see FIG. 46(c)) can be gripped in an optimal state by making the workpiece W4 lie along the gripper.

To further explain the difference from Embodiment 2 with reference to FIG. 42, as is clear from a comparison with FIG. Even in a state in which the drive is stopped while the differential gear 71 is aligned with the differential gear 71, that is, in a state in which drive transmission to the differential gear 41 is stopped, the actuator 11 still transmits the drive force to the side shaft 81 of the differential gear 71. As a result, the central finger (2A) is driven, so that the middle part of the work W4 (different diameter object, Fig. 46) is thinner than the work W3 (conical object, see Fig. 46(b)). (c)), it is possible to make each joint of the central finger (2A) fit along the outer surface of the workpiece W.

In this way, in the robot hand 1 equipped with the fingers 2A to 2C of this embodiment, the driving force of one actuator 11 is transmitted to the fingers 2 (2A, 2B, 2C), and the driving force of the finger 2A is By interposing the differential device 71 in the transmission path and interposing the differential devices 41, 71 in the drive transmission path of the fingers 2B and 2C, the base of each finger can be easily applied even to workpieces W having different diameter shapes. The joints 111, middle joints 121, and terminal joints 131 can be sequentially rotated according to the shape of the workpiece W4 that each finger comes into contact with, so that the fingertips 139 of the terminal joints 131 of each finger fit into the outer surface of the workpiece W4. The workpiece W4 (object having a different diameter shape, see FIG. 46(c)) can be gripped in an optimal state by making the workpiece W4 lie along the handlebar.

That is, the drive mechanism of the fourth embodiment has three fingers (2A, 2B, 2C) and grips an article by transmitting the driving force of the actuator 11. It has a driving force transmission device that connects the The three fingers are a first finger (2A) placed in the center on one end side of the palm surface (106) of the main body of the robot hand, and a second finger placed at a distance on the other end side of the palm surface. (2B) and the third finger (2C). The driving force transmission device includes a driving side case (differential case 72) to which the driving force of the actuator 11 is transmitted, and a first finger side shaft (provided at one end side of the driving side case) that transmits the driving force to the first finger. a first differential device (71) including a side shaft (81), a side shaft (91) provided on the other end side of the driving side case, and a driven side case to which the driving force transmitted to the side shaft is transmitted. (differential case 42), a second finger side shaft (side shaft 51) provided on one end side of the driven side case and transmitting driving force to the second finger, and a second finger side shaft (side shaft 51) provided on the other end side of the driven side case. It has a second differential device (41) including a third finger side shaft (side shaft 61) that transmits driving force to the three fingers. Therefore, according to the drive mechanism of the fourth embodiment, the accuracy can be improved not only for conical objects as shown in FIG. 46(b) but also for objects having different diameters as shown in FIG. 46(c). It can be held well and stably. In other words, with only one actuator, it is possible to realize finger and joint movements suitable for the shape of objects with different diameters, and also to realize movement of fingers and joints suitable for the shape of objects with different diameters. Even if an external force is generated, it is possible to maintain stable gripping of the object without changing the gripping position.

Note that when the actuator 11 is driven to release the gripped workpiece W, the nodes move away from the workpiece in the opposite order to the order in which the nodes fit into the outer surface of the workpiece W when gripped, as in the second embodiment. Specifically, first the fingertip 139 (distal joint 131) separates from the workpiece W, then the middle joint 121 separates from the workpiece W, finally the base joint 111 separates from the workpiece W, and then the base joint 111, the middle joint 121, and the terminal joint Rotation is started while maintaining the linear stretching posture of 131.
Furthermore, when gripping a workpiece W4 (object having a different diameter shape, see FIG. 46(c)), etc., and releasing the workpiece W gripped by the fingers 2A to 2C in different postures, the fingers 2A to 2C are in a linear stretching posture. The postures of the robots may not match. For example, even though the finger 2B in the linearly stretched posture is far from the finger 2A in the linearly stretched posture, the finger 2C in the linearly stretched posture is close to the finger 2A in the linearly stretched posture. It can be a posture. Even in such a case, by driving the actuator 11 in a direction in which the fingers 2A, 2B, and 2C move away from each other (the fingers open), the postures of the fingers 2 in the linearly stretched posture are aligned.

The principle is realized by the abutment surface 114t1 of each finger abutting against the abutment surface 106t1, as in the second embodiment.
The drive force transmitted to the first finger that abuts the abutment surface 114t1 and the abutment surface 106t1 is stopped by a differential device interposed in the drive transmission path, and the drive is transmitted to the finger that abuts the second finger. As for power, the drive is stopped by a differential device interposed in the drive transmission path. When the abutment surface 114t1 of the last finger abuts against the abutment surface 106t1, the drive to that finger stops, and the drive by the actuator 11 stops.
With such a configuration, even when releasing the workpiece W and gripping it again, the fingers 2 can resume gripping from a linearly stretched posture as shown in FIG. 20.

Similarly to the second embodiment, in the robot hand 1 of the fourth embodiment, the driving force of one actuator 11 is applied to drive links 114 (114A, 114B, 114C) that drive the fingers 2 (2A, 2B, 2C). Cylindrical worms 26 (26A, 26B, 26C) and worm wheels 27 (27A, 27B, 27C) are used for the transmission path. The cylindrical worm 26 (26A, 26B, 26C) and the worm wheel 27 (27A, 27B, 27C) constitute a transmission device 25 (25A, 25B, 25C) with a self-locking mechanism.
In the fourth embodiment, the self-locking transmission device 25A is provided on the output side of the differential device 71 (the side where the finger 2 is located), and the self-locking transmission device 25A is provided on the output side of the differential device 41 (the side where the finger 2 is located). By providing the transmission devices 25B and 25C with lock mechanisms, even if an external force is applied to the robot hand 1, differential movement will not occur in the side shafts 81 and 91, and differential movement will not occur in the side shafts 51 and 61. No movement occurs, and a secure grip is achieved with the fingers 2A, 2B, and 2C.

The determination of the gripping status of the workpiece in the fourth embodiment is the same as that in the second embodiment, and the explanation thereof will be omitted.
Also in the fourth embodiment, as in the second embodiment, the control unit 1C of the robot hand 1 is connected to an encoder 11E that detects the rotation angle of the drive output shaft (not shown) of the actuator 11. The drive link plates 114P (114PA, 114PB, 114PC) are obtained based on the information of the encoder 11E and the rotation information of the reading magnets 114rm (114rmA, 114rmB, 114rmC) detected by the reading heads 114rh (114rhA, 114rhB, 114rhC). The system verification of the drive mechanism of the robot hand 1 is performed based on the information of the rotation angle 112α (112αA, 112αB, 112αC) around the metacarpophalangeal joints 112 (112A, 112B, 112C).

Specifically, the control unit 1C controls the rotation of the differential case 72 based on the information from the encoder 11E, taking into account the reduction ratio of the transmission device 11T and the reduction ratio of the gear transmission mechanism composed of the drive gear 31G and the driven gear 33G. Detecting corners. For convenience of explanation, this detection angle is defined as 72r4.
The control unit 1C also controls the rotation angle 112αA of the drive link plate 114A around the metacarpophalangeal joint 112A, which is acquired based on the rotation information of the reading magnet 114rmA detected by the reading head 114rhA of the finger 2A. The rotation angle of the side shaft 81 is detected in consideration of the reduction ratio of the self-locking transmission device 25A and the reduction ratio of the gear transmission mechanism composed of the drive gear 81G and the transmission gear 83G. For convenience of explanation, this detection angle is defined as 81r4.

The control unit 1C detects the rotation angle of the side shaft 91 using the following equation (3) based on the detected rotation angle (72r4) of the differential case 72 and the detected rotation angle (81r4) of the side shaft 81. For convenience of explanation, this detection angle is defined as 91r4.
Rotation angle of side shaft 91 = rotation angle of differential case 72 x 2
- Rotation angle of side shaft 81...(3)

Further, the control unit 1C detects the rotation angle of the differential case 42 based on the detected rotation angle (91r4) of the side shaft 91, taking into consideration the reduction ratio of the gear transmission mechanism composed of the drive gear 91G and the transmission gear 93G. are doing. For convenience of explanation, this detection angle is defined as 42r4.
The control unit 1C also controls the rotation angle 112αB of the drive link plate 114B around the metacarpophalangeal joint 112B, which is acquired based on the rotation information of the reading magnet 114rmB detected by the reading head 114rhB of the finger 2B. The rotation angle of the side gear 51 is detected in consideration of the reduction ratio of the self-locking transmission device 25B and the reduction ratio of the belt transmission mechanism composed of the drive pulley 51P, the transmission belt 52, and the driven pulley 53P. For convenience of explanation, this detection angle is defined as 51r5.

Further, the control unit 1C controls the rotation angle 112αC of the drive link plate 114C around the metacarpophalangeal joint 112C, which is acquired based on the rotation information of the reading magnet 114rmC detected by the reading head 114rhC of the finger 2C. The rotation angle of the side gear 61 is detected in consideration of the reduction ratio of the self-locking transmission device 25C and the reduction ratio of the belt transmission mechanism composed of the drive pulley 61P, the transmission belt 62, and the driven pulley 63P. For convenience of explanation, this detection angle is defined as 61r5.
Further, the control unit 1C calculates the average value based on the detected rotation angle 51r5 of the side gear 51 and the detected rotation angle 61r5 of the side gear 61 as shown in the following equation, and detects the rotation angle of the differential case 42. . As shown in equation (4), this detection angle is defined as 42r5 for convenience of explanation.
Rotation angle 42r5 of differential case 42
=(Rotation angle of side shaft 51 + rotation angle of side shaft 61)÷2
・・・・・・(4)

The control unit 1C compares the values of the rotation angles (42r4, 42r5) of the differential case 42 detected by the two methods, and if they are equal based on tolerance (sensor resolution and sensor detection accuracy error), drives the robot hand 1. Determine that the organization's system is operating normally.
On the other hand, when the values of the rotation angle (42r4, 42r5) of the differential case 42 detected by the two methods are compared, and if they are not equal even after considering the allowable error (sensor resolution and sensor detection accuracy error), the robot hand 1 is driven. It is determined that the organization's system is not operating properly.

Specifically, if the values of 42r4 and 42r5 are different, the transmission device 11T, the self-locking transmission device 25 (25A, 25B, 25C), the differential devices 41 and 71, or the drive gear 31G, a gear transmission device consisting of a driven gear 33G, a gear transmission device consisting of a driving gear 81G and a driven gear 83G, a gear transmission device consisting of a driving gear 91G, an intermediate gear 92G, and a driven gear 93G. , tooth skipping due to gear tooth wear, belt transmission mechanism consisting of drive pulley 51P, transmission belt 52 and driven pulley 53P, belt elongation and step-out of belt transmission mechanism consisting of drive pulley 61P, transmission belt 62 and driven pulley 63P, rotation angle sensor. (11E, 114rhA, 114rmA, 114rhB, 114rmB, 114rhC, 114rmC) has become loose or has malfunctioned, and it is determined that the drive mechanism system of the robot hand 1 is not operating normally.

In addition, similarly to the second embodiment, the control unit 1C of the robot hand 1 controls the metacarpophalangeal joint 112, the proximal interphalangeal joint 122, and the distal interphalangeal joint 132 of the finger 2, which has a plurality of joints. The joint angles of are obtained.
Backlash in the proximal four-bar link mechanism 103 that constitutes the finger 2, play in the distal four-bar link mechanism 104, rotation angle sensor (111rhA, 111rmA, 121rhA, 121rmA, 111rhB, 111rmB, 121rhB, 121rmB, 111rhC, 111rmC, 121rhC , 121rmC) becomes loose or malfunctions, each finger 2( 2A, 2B, 2C) and the assumed posture preset in the memory 1M no longer match.
Even in such a case, the control unit 1C determines that the drive mechanism system of the robot hand 1 is not operating normally.

In the above embodiments, a self-locking mechanism-equipped transmission device was used as a transmission device for transmitting the driving force from the actuator to the fingers. Alternatively, various mechanisms can be employed, such as one that detects an external force generated by a change in the center of gravity of the object to be gripped, and uses an electromagnetic actuator to suppress the opening and closing of the fingers.

1...Robot hand 1C...Control unit 1M...Memory 2, 2A, 2B, 2C...Finger 5...Base frame 11...Actuator 11E...Encoder 11T...Transmission device 21, 21A, 21B...Self Transmission device with lock mechanism 22, 22A, 22B...screw shaft [example: trapezoidal screw]
23, 23A, 23B...Screw nut 24, 24A, 24B...Linear guide 25, 25A, 25B, 25C...Transmission device with self-locking mechanism 26, 26A, 26B, 26C...Cylindrical worm 27, 27A, 27B, 27C... Worm wheel 31... Transmission shaft 31P... Drive pulley 32... Transmission belt 33P... Driven pulleys 31G, 34G... Drive gears 33G, 36G... Driven gears 41, 71... Differential devices 42, 72 ... Differential cases 46, 47 ... Torsion springs 51, 61, 81, 91 ... Side shaft 51P ... Drive pulley 52 ... Transmission belt 53P ... Driven pulleys 53rh, 63rh ... Reading head 61P ... Drive pulley 62 ...Transmission belt 63P ... Driven pulleys 81G, 91G ... Drive gears 83G, 93G ... Driven gear 92 ... Shaft 92G ... Intermediate gear

103... Proximal four-bar link mechanism 104... Distal four-bar link mechanism 105... Palm 106... Palm surface 106V... Virtual vertical plane 109... Wrist 110... Actuator 110E... Encoder 110T... Transmission device 111... Proximal joints 111rh, 121rh... Reading heads 111rm, 121rm... Reading magnets 111t1, 121t1, 121t2, 131t2... Abutment surface 112... Metacarpophalangeal joint 113... Base relay link 114... Drive link 114rh...reading head 114rm...reading magnet 115...base intermediate link
(116...first connection shaft)
(117...second connection shaft)
119, 129... Virtual link 120... Intermediate link plate 121... Middle joint 122... Proximal interphalangeal joint 123... Distal relay link 125... Distal intermediate link
(126...Third connection shaft)
(127...4th connection shaft)
131... Distal joint 132... Distal interphalangeal joint 139... Fingertips L1, L2... Line segments W1, W2, W3, W4... Work

221, 221A, 221B...Linear motion device (no self-locking mechanism)
222, 222A, 222B...screw shaft [example: ball screw]
223, 223A, 223B...Ball screw nut 224, 224A, 224B...Linear guide

Claims (3)

A finger drive mechanism of a robot hand that has three fingers and grips an article by transmitting the driving force of one actuator,
a driving force transmission device connecting the actuator and each finger,
The three fingers are
The robot hand is composed of a first finger placed in the center on one end side of the palm surface of the main body of the robot hand, and a second finger and a third finger placed at a distance from each other on the other end side of the palm surface,
The driving force transmission device includes:
a drive-side case to which the driving force of the actuator is transmitted; a first finger-side shaft provided at one end of the drive-side case and transmitting the driving force to the first finger; and the other end of the drive-side case. a first differential device including a side shaft provided in the
a driven side case to which the driving force transmitted to the side shaft is transmitted; a second finger side shaft provided on one end side of the driven side case and configured to transmit the driving force to the second finger; and the driven side case. A drive mechanism comprising: a second differential device including a third finger side shaft provided on the other end side and transmitting driving force to the third finger. A finger drive mechanism of a robot hand that has three fingers and grips an article by transmitting the driving force of one actuator,
A driving force transmission device including a differential device that distributes the driving force transmitted from the actuator, and a driving force transmission device connecting the actuator and each finger,
The three fingers are
The robot hand is composed of a first finger placed at the center of one end side of the palm surface of the main body of the robot hand, and a second finger and a third finger placed apart from each other on the other end side of the palm surface,
The differential device is
a case to which the driving force of the actuator is transmitted;
a second finger-side shaft provided at one end of the case and transmitting driving force to the second finger;
a third finger side shaft provided on the other end side of the case and transmitting driving force to the third finger;
a first torsion spring having one end fixed to the case and the other end fixed to the second finger-side shaft;
A drive mechanism including a second torsion spring having one end fixed to the case and the other end fixed to the third finger side shaft. The drive mechanism according to claim 1;
three joint angle sensors that are associated with each of the three fingers and detect joint angles of a plurality of joints in each finger;
a motor shaft sensor that detects an input rotation angle corresponding to the rotation angle of the output shaft of the actuator;
Whether or not the drive mechanism is operating normally based on the three joint angle sensors, the motor shaft sensor, dimensional information (geometric relationships) of each part, and the reduction ratio of the drive force transmission device. a control unit that determines the
The control unit includes:
Using the detection value by the motor shaft sensor and the detection value by the joint angle sensor associated with the first finger, the rotation angle of the drive-side case and the rotation angle of the first finger-side shaft is used. Determining first rotation angle data indicating the rotation angle of the driven side case based on the rotation angle of the side shaft,
the rotation angle of the second finger-side shaft obtained from the detection value by the joint angle sensor associated with the second finger; and the rotation angle obtained from the detection value by the joint angle sensor associated with the third finger. Using the rotation angle of the third finger side shaft, obtain second rotation angle data indicating the rotation angle of the driven side case,
The robot hand is configured to determine whether or not the drive mechanism is operating normally based on the first rotation angle data and the second rotation angle data.

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