CN100450732C - Under drive mechanical finger device of connecting rod - Google Patents

Abstract

A connection rod type under-driven finger unit for manipulator is composed of the first and second finger segments and an under-driven joint between said two finger segments. Said under-driven joint consisting of joint axle, active slide block, connecting-rod unit, and torsional spring. Said connecting-rod unit comprises the drive rod and the driven rod.

Description

Connecting rod underactuated mechanical finger device

technical field

The invention belongs to the technical field of anthropomorphic robots, and in particular relates to a structural design of a shape-adaptive underactuated mechanical finger device.

Background technique

Similar to humans, most functions of anthropomorphic robots are realized through hand manipulation, so the hand structure is an important part of anthropomorphic robots, and its design is one of the key technologies of anthropomorphic robots. In order to increase the anthropomorphism of the hand, more joint degrees of freedom should be designed for the hand. However, in order to reduce the control difficulty of the anthropomorphic robot hand, as well as reduce the volume and weight of the hand, it is necessary to reduce the number of drivers. Certain contradictions, in addition, in order to better grasp the object, it is also necessary for the finger to have a certain degree of adaptability when grasping the object. The design of link underactuated mechanical finger device can better achieve the three goals of more joint degrees of freedom, less number of drives, and strong adaptability when grasping objects of different shapes and sizes.

An existing adaptive underactuated mechanical finger device, such as the Chinese invention patent CN 1365875A, contains the first finger segment, the second finger segment and an underactuated joint, and the underactuated joint contains an active plate, an underactuated joint shaft and a multi-stage gear Acceleration agency. The external force causes the active plate to rotate around the underactuated joint axis, and the second finger segment is rotated substantially by the multi-stage gear speed-up mechanism to fasten the object.

The weak point of this device is: this device adopts multistage gear transmission, is a gear box at the joint, and volume is larger; One end of the finger is much thicker than the other end, which is quite different from the human hand; although the device is basically feasible to imitate the thumb, it is not suitable for imitating other fingers except the thumb, and if multiple devices are connected to form index finger and middle finger , ring finger and little finger, the appearance will be too different from the human hand.

An existing adaptive underactuated mechanical finger device, such as the Chinese invention patent CN 1410223A, includes a first finger segment, an underactuated joint and a second finger segment, and the underactuated joint contains an active slider, a joint shaft and a rack and pinion mechanism . External force drives the active slider to slide on the first finger segment, and at the same time, the rack fixed on the active slider moves in the first finger segment, driving the gear meshed with the rack to rotate around the joint axis to realize the rotation of the second finger segment and fasten the object.

The weak point of this device is: this device adopts rack and pinion drive, and device is more complicated, and the quality of palm is bigger, and energy consumption is higher. In order to achieve a good under-actuation effect, that is, to achieve a large angle of rotation of the second finger segment, the gear used must have a small radius, which is difficult to process and high in cost. Moreover, the rack and pinion mechanism needs good lubrication and sealing, and the use cost is relatively high.

Contents of the invention

The object of the present invention is to propose a connecting rod underactuated mechanical finger device in order to overcome the shortcomings of the prior art. The mechanical finger device has the characteristics of small size, light weight, easy processing and maintenance, etc., thereby further reducing processing difficulty and maintenance cost, and making the shape of the mechanical finger more similar to that of a human hand.

The present invention adopts the following technical scheme: an underactuated mechanical finger device of a connecting rod, comprising a first finger section, a second finger section and an underactuated joint arranged between them, and the underactuated joint includes an active slider, The joint shaft and the torsion spring sleeved on the joint shaft, the joint shaft is installed on the first finger segment, the second finger segment is sleeved on the joint shaft, one end of the torsion spring is connected to the first The finger segment is fixedly connected, and the other end of the torsion spring is fixedly connected with the second finger segment. It is characterized in that: the under-actuated joint also includes a linkage mechanism, and the linkage mechanism is composed of a driving rod and a driven rod. One end of the rod is hinged to the first finger segment, the other end is hinged to the driven rod, and the other end of the driven rod is hinged to the second finger segment. The axis of the hinge point is parallel to the axis of the joint shaft; the active slider is embedded in the In a finger segment, and in contact with the active rod.

The technical feature of the present invention is that: the joint shaft is composed of a left joint half shaft and a right joint half shaft, and the left joint half shaft and the right joint half shaft are coaxially installed on the first finger segment.

Another technical feature of the present invention is that: the structural parameters of each part of the underactuated joint conform to the following relationship:

Let the length of the active rod be L ₁ , the length of the driven rod be L ₂ , the distance between the axis of the hinge point of the driven rod and the second finger section to the axis of the joint axis be L ₃ , and the contact line between the active slider and the active rod to the active rod The vertical distance between one end and the axis of the hinge point of the first finger segment is h, then: L ₁ : h=1.5-2.5:1; L ₂ : h=3-5:1; L ₃ :h=0.6-1.2:1.

The first finger section of the present invention is composed of the first finger section skeleton, the back panel and the active slider baffle, and the three are fixedly connected together. The active slider is composed of a slider body and a slider surface cover fixed on the surface of the slider body, and the slider surface cover is made of industrial rubber material.

Compared with the prior art, the present invention has the following advantages and outstanding effects: the device utilizes the transmission of the link mechanism to realize the rotation of the second finger section, and the short movement distance of the active slider can bring Rotation of the second finger at a large angle. The device is only driven by two connecting rods, the active rod and the driven rod. The number of connecting rods is small, the structure is simple and reliable, the volume and quality of the device are reduced, and only low control system requirements are required, so that the mechanical finger device has Small size, light weight, easy processing and maintenance, etc., so that the shape of the mechanical finger can be more similar to the human finger, further reducing the processing difficulty and maintenance cost. The device can be used as a finger or a part of a robot anthropomorphic hand, and can also be connected in series to form a finger with high shape adaptability and high underactuation. The human hand is used to achieve the effect of high degree of freedom and high adaptability of the robot anthropomorphic hand.

Description of drawings

Fig. 1 is a front view of an embodiment of the link underactuated mechanical finger device provided by the present invention.

Fig. 2 is a right side view of Fig. 1 .

Fig. 3 is a sectional view along line A-A of Fig. 1 .

Fig. 4 is a front view of the embodiment without the slider surface cover 11.

Fig. 5 is a schematic diagram of the installation of the active slider in this embodiment.

Fig. 6 is an exploded view of this embodiment.

Fig. 7 is an exploded view when the joint axis is designed to consist of a left joint semi-axis and a right joint semi-axis.

Fig. 8 is a side sectional view of the second segment of the finger in this embodiment after rotation.

9 , 10 , 11 , and 12 are schematic diagrams of objects grasped by the fingers of this embodiment in which the first finger segment is fixed on the palm.

13 , 14 , 15 , and 16 are schematic diagrams of objects grasped by the fingers of this embodiment after the first finger segment is connected to the active joint.

Fig. 17 is a front view of an underactuated two-joint finger to which this embodiment is applied.

Fig. 18 is a right side view of an underactuated two-joint finger to which this embodiment is applied.

Fig. 19 is a schematic diagram of the underactuated double-joint finger applying this embodiment grasping a large-sized object under the rotation of two underactuated joints, and the root finger segment is connected with the active joint.

Fig. 20 is a front view of the robot anthropomorphic multi-fingered hand to which this embodiment is applied.

In Figures 1 to 20:

1. First finger segment, 2. Second finger segment, 3. Underactuated joint,

4. Active slider, 5. Link mechanism, 6. First finger skeleton,

7. Back panel, 8. Active slider bezel,

9. Back panel groove, 10. Slider body, 11. Slider surface cover,

12. Boss, 13. Rivet the boss to the skeleton of the first finger segment,

14. Active lever, 15. Driven lever,

16. The root hinge shaft used to hinge the boss 12 and the active rod 14,

17. An intermediate hinge shaft for hinged driving rod 14 and driven rod 15,

18. The end hinge shaft for hinged driven rod 15 and second finger section 2,

19. Joint axis, 19(a). Left joint semi-axis, 19(b). Right joint semi-axis,

20. Torsion spring, 21. The active slider chute on both sides of the first finger segment skeleton 6,

22. The slider body protrusions on both sides of the slider body 10,

23. Root finger segment, 24. Middle finger segment, 25. End finger segment,

26. Root Active Slider, 27. Middle Active Slider, 28. Middle Underactuated Joint,

29. Terminal underactuated joint, 30. Palm, 31. Thumb,

32. Index finger, 33. Middle finger, 34. Ring finger,

35. Little finger, 36. Thumb root joint,

37. The underactuated joint at the end of the thumb, 38. The base joint of the index finger,

39. Underactuated joint in the middle of the index finger, 40. Underactuated joint at the end of the index finger,

41. Middle finger root joint, 42. Middle finger middle underactuated joint,

43. The underactuated joint at the end of the middle finger, 44. The root joint of the ring finger,

45. Middle underactuated joint of the ring finger, 46. Underactuated joint at the end of the ring finger,

47. Little finger root joint, 48. Little finger middle underactuated joint,

49. Underactuated joint at the end of the little finger.

Detailed ways

The content of the specific structure and working principle of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

An embodiment of a link underactuated mechanical finger device designed by the present invention is shown in Figures 1 and 2 for its appearance and shown in Figures 3, 4, 5, 6 and 7 for its principles. The device comprises a first finger section 1, a second finger section 2 and an underactuated joint 3 arranged between the two. The underactuated joint 3 includes an active slider 4, a joint shaft 19, a link mechanism 5 and a sleeve. A torsion spring 20 is arranged on the joint shaft. The joint shaft is installed on the first finger segment, and the second finger segment is sleeved on the joint shaft; one end of the torsion spring is fixedly connected to the first finger segment, and the other end of the torsion spring is connected to the second finger segment. Finger section is fixedly connected; Described link mechanism is made up of active rod 14 and driven rod 15, and one end of active rod is hinged with first finger segment, and the other end is hinged with driven rod; The other end of driven rod is hinged with second finger. The segment is hinged, and the axis of the hinge point is parallel to the axis of the joint shaft; the active slider is embedded in the first finger segment and is in contact with the active rod.

The joint shaft 19 has two design schemes: the first one is designed as a whole shaft, the exploded view of this design is shown in Figure 6; in order to avoid the movement interference between the driven rod and the joint shaft during motion, the In the two schemes, the joint shaft is designed to be composed of the left joint semi-axis 19a and the right joint semi-axis 19b, and the left joint semi-axis and the right joint semi-axis are coaxially installed on the first finger segment. The exploded view of this design is shown in Figure 7 shown.

In order to better realize the underactuated function of the large-angle rotation of the second finger segment caused by the sliding of the small displacement of the active slider, the structural parameters of each part of the underactuated joint of the connecting rod underactuated mechanical finger device need to satisfy the following relationship: Let the length of the active rod be L ₁ , the length of the driven rod be L ₂ , the distance between the axis of the hinge point of the driven rod and the second finger segment to the axis of the joint axis be L ₃ , and the contact line between the active slider ÷ and the active rod to the active The vertical distance between one end of the rod and the axis of the hinge point of the first finger segment is h, then: L ₁ : h=1.5～2.5:1; L ₂ : h=3～5:1; L ₃ :h=0.6～1.2:1 .

The first finger section is composed of the first finger section skeleton 6, the back panel 7 and the active slider baffle 8, and the three are fixedly connected together. In order to embed the active slider into the first finger segment, an active slider chute 21 is opened on the first finger segment skeleton, and the active slider baffle covers the active slider chute to prevent active The slider is disengaged from the first finger segment.

In order to facilitate the hinge connection of the active lever on the first finger section, in this embodiment, a boss 12 is riveted with a rivet 13 on the skeleton of the first finger section, and one end of the active lever uses a root hinge shaft 16 and the boss. table hinged.

The other end of the active rod is hinged with one end of the driven rod with the middle hinge shaft 17, and the other end of the driven rod is hinged with the second finger segment with the terminal hinge shaft 18.

Described active slider is made up of slider body 10 and slider surface cover 11, and slider surface cover adopts the industrial rubber material that has suitable elasticity. In this way, when grasping an object, a soft finger-surface contact will be formed between the surface of the finger and the object. On the one hand, the degree of constraint of the finger on the object is increased, and on the other hand, the friction force can be increased, thereby increasing the stability of the grasped object. There are slider body protrusions 22 on both sides of the slider body, and the slider body protrusions are embedded in the active slider chute on the first finger frame to play the role of positioning and guiding, so as to ensure the movement direction of the active slider is along the direction of the active slider chute.

The torsion spring 20 is sleeved on the joint shaft, one end is fixedly connected to the first finger segment, and the other end is fixedly connected to the second finger segment. Its function is: keep the second finger upright in the natural state; when the object is released, bring the second finger back to the natural position, drive the linkage mechanism to return to the initial position, and push back the active slider in the first finger natural location.

The working principle of the present embodiment is described as follows:

(1) If the first finger segment 1 of the present embodiment is fixed on the palm of the robot anthropomorphic hand, the working principle of the present embodiment, as shown in Figures 9, 10, 11, and 12, is described as follows:

When the robot anthropomorphic hand does not touch the object, the fingers are in a free state. At this time, the torque of the torsion spring 20 prevents the second finger section 2 from rotating, and the fingers remain straight.

When the robot anthropomorphic hand grabs the object, the other fingers rotate and press the object, the object squeezes the active slider 4, and the active slider moves a certain displacement d in the first finger segment 1 along the direction perpendicular to the surface of the finger, and at the same time presses the active rod 14 Rotate in the first finger section with the root hinge shaft 16 as the axial direction, drive the driven rod 15 to move, and then drive the second finger section 2 to rotate around the joint axis 19 at a large angle α until the second finger section touches the object, thus The robotic anthropomorphic hand will have automatic adaptation to the size and shape of objects. After the finger grabs the object in this embodiment, the position change of the link mechanism is shown in FIG. 8 . In order to prevent the link mechanism from moving and interfering with the back panel 7 when the second finger segment rotates, a back panel groove 9 is provided on the back panel.

Set the vertical distance from the contact line between the active slider 4 and the active rod 14 to the axis of one end of the active rod and the hinge point of the first finger section as h. In this embodiment, h is relatively small, so a small displacement d of the active slider can make the active rod rotate through a larger angle, thereby driving the driven rod 15 and the second finger segment 2 to move, and finally realizing the second finger segment Turn through a larger angle α. This makes the second finger section rotate as if it is driven by a driver such as a motor, and can fast hold objects, realizing the purpose that the finger itself can have multiple joint degrees of freedom without using a driver.

When the robot anthropomorphic hand releases the object, the other fingers leave the object under the rotation of the motor, and the object no longer presses the active slider 4, and the torsion spring 20 will drive the second finger section 2 to turn back to the initial position around the joint axis 19, driving the chain The rod mechanism 5 returns to the natural state, and then presses the active slider 4 back to the initial position. Since the outer side of the active slider chute 21 is covered with the active slider baffle plate 8, the active slider can be prevented from breaking away from the first finger section.

(2) If the root of the first finger section 1 of this embodiment is socketed on an active joint driven by a driver, the working principle of this embodiment, as shown in Figures 13, 14, 15, and 16, is described as follows:

When the robot anthropomorphic hand grabs an object, the active joint covered with the first finger segment 1 rotates under the action of the driving torque M, so that the entire underactuated finger rotates around the active joint at the root until the active slider 4 touches the object. Under the action of other fingers, it cannot leave. Therefore, when the active joint continues to rotate, the active slider 4 is blocked by the object and moves to the first finger segment along the direction perpendicular to the finger surface. The subsequent grabbing process is similar to (1). .

The underactuated two-joint finger applying the embodiment of the present invention is shown in Figs. 17 and 18 .

The underactuated double-joint finger applying the embodiment of the present invention is composed of a base phalanx 23 , a middle phalanx 24 , an end phalanx 25 , a middle underactuated joint 28 and an end underactuated joint 29 .

The principle of applying the underactuated double-joint finger of the embodiment of the present invention to grasp an object by rotating two underactuated joints is shown in FIG. 19 . When the robot anthropomorphic hand grabs an object, the object presses the root active slider 26 under the action of other fingers (if the root finger segment 23 of the underactuated two-joint finger is sleeved on an active joint, the underactuated two-joint finger Under the active rotation of the root active joint, the object is pressed, and the object is hindered by other fingers and cannot leave, so it reacts on the root active slider 26). At this time, the root active slider moves in the root finger section along the direction perpendicular to the finger surface. Make the middle finger section 24, the end underactuated joint 29, and the end finger section 25 rotate quickly around the middle underactuated joint 28, as if there is a driver such as a motor actively driving the middle underactuated joint until the middle active slider 27 touches the object. The middle active slider is hindered by the object and no longer moves. At this time, the object continues to press the root active slider 26, causing the middle finger section 24, the end underactuated joint 28, and the end finger section 25 to continue to rotate rapidly around the middle underactuated joint. The middle finger segment (rotating) moves relative to the middle active slider (not moving), driving the end finger segment to rotate around the end underactuated joint quickly, as if the end underactuated joint is actively driven by a driver such as a motor, until the end finger segment touches object. The underactuated double joint finger has automatic adaptability to objects of different shapes and sizes.

The robot anthropomorphic multi-fingered hand applied in this embodiment is shown in FIG. 20 .

The robot anthropomorphic multi-fingered hand applying this embodiment includes palm 30, thumb 31, index finger 32, middle finger 33, ring finger 34, little finger 35, thumb root joint 36, thumb terminal underactuated joint 37, index finger root joint 38, index finger middle underactuated joint Joint 39, index finger end underactuated joint 40, middle finger base joint 41, middle finger underactuated joint 42, middle finger end underactuated joint 43, ring finger base joint 44, ring finger middle underactuated joint 45, ring finger end underactuated joint 46, little finger base joint 47, underactuated joint 48 in the middle of the little finger, and underactuated joint 49 at the end of the little finger.

Wherein, the thumb 31 uses a single structure of this embodiment, and the index finger 32, middle finger 33, ring finger 34, and little finger 35 each use two structures of this embodiment. The root joints of each finger are active joints driven by motors. The middle joints and end joints of each finger are underactuated joints without drivers, that is, the structure of this embodiment is applied.

Claims (6)

1. A connecting rod underactuated mechanical finger device, comprising a first finger section (1), a second finger section (2) and an underactuated joint (3) arranged between the two, and the underactuated joint contains The active slider (4), the joint shaft (19) and the torsion spring (20) sleeved on the joint shaft, the joint shaft is installed on the first finger segment, and the second finger segment is sleeved on the joint On the shaft, one end of the torsion spring is fixedly connected to the first finger segment, and the other end of the torsion spring is fixedly connected to the second finger segment, and it is characterized in that: the underactuated joint also includes a link mechanism (5), Described link mechanism is made up of driving rod (14) and driven rod (15), and one end of driving rod is hinged with the first finger segment, and the other end is hinged with driven rod; the other end of driven rod is connected with the second finger segment Hinged, the axis of the hinge point is parallel to the axis of the joint shaft; the active slider is embedded in the first finger segment and is in contact with the active rod. 2. The connecting rod underactuated mechanical finger device according to claim 1, characterized in that: the joint axis (19) is composed of a left joint semi-axis (19a) and a right joint semi-axis (19b), and the The left joint semi-axis and the right joint semi-axis are coaxially installed on the first finger segment. 3. The connecting rod underactuated mechanical finger device according to claim 1 or 2, wherein the structural parameters of each part of the underactuated joint conform to the following relationship: Let the length of the active rod be L ₁ , the length of the driven rod be L ₂ , the distance between the axis of the hinge point of the driven rod and the second finger section to the axis of the joint axis be L ₃ , and the contact line between the active slider and the active rod to the active rod The vertical distance between one end and the axis of the hinge point of the first finger segment is h, then: L ₁ : h=1.5-2.5:1; L ₂ : h=3-5:1; L ₃ :h=0.6-1.2:1. 4. The connecting rod underactuated mechanical finger device according to claim 1, characterized in that: the first finger section is composed of the first finger section skeleton (6), the back panel (7) and the active slider baffle plate ( 8) Composition, the three are fixed together. 5. The connecting rod underactuated mechanical finger device according to claim 1, characterized in that: the active slider consists of a slider body (10) and a slider surface cover (11) fixed on the surface of the slider body ), the slider surface cover adopts industrial rubber material. 6. A high and under-actuated mechanical finger device adopting a device as claimed in claim 1, characterized in that: the high and under-actuated mechanical finger device comprises more than two finger segments, and is provided between every adjacent two finger segments The underactuated joint.

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