A composite displacement robot finger device and robot hand device

Abstract

The present invention provides a compound displacement robot finger device and a robot hand device for grasping a workpiece. The compound displacement robot finger device includes: a base; a first finger joint, the first finger joint being rotatably connected to the base; a second finger joint, the second finger joint being rotatably connected to the first finger joint; a third finger joint, the third finger joint being rotatably connected to the second finger joint; a first drive rod, the first drive rod being rotatably connected to the base; a first transmission rod, the first transmission rod being rotatably connected to the first drive rod; a second transmission rod, a third transmission rod, and a second drive rod; a first limiting rod limiting the motion trajectory of the second transmission rod; and a second limiting rod limiting the motion trajectory of the connection point between the first finger joint and the second finger joint. The compound displacement robot finger device and the robot hand device of the present invention can more conveniently clamp a workpiece.

Description

Technical Field

[0001] The present invention relates to the field of robot technology, and in particular to a compound displacement robot finger device and a robot hand device. Background Art

[0002] In robotics research, robotic hands, as important end-effectors, have received considerable attention. Existing robotic hands possess numerous degrees of freedom and can be combined with sensing to accomplish various grasping tasks. The human hand's numerous joints, dexterity, and diverse grasping patterns make designing robotic hands that mimic the human hand challenging. Fully actuated fingers, where all joints are driven by motors, present significant challenges in real-time sensing and control, are costly, and hinder widespread application. Prior art underactuated fingers include coupled grasping fingers, parallel gripping fingers, and adaptive envelope gripping fingers. Parallel gripping (also known as flat gripping) fingers maintain their original position relative to the base during movement—the end segments only move in translation. This mode is suitable for parallel gripping of objects on work surfaces. Coupled fingers, with multiple joints rotating simultaneously in a forward direction, rotate their segments simultaneously in a specific ratio during movement. These coupled fingers offer more dexterity and faster grasping speeds, making them suitable for grasping objects on desktops with their end segments. Whether it is a flat clamping finger or a coupled finger, when enveloping and grasping an object, it cannot adapt to objects of different shapes and sizes, and the grasping is not stable enough. When the adaptive enveloping grasping finger is in motion, when the proximal joint rotates, the distal joint does not rotate. After the proximal finger segment contacts the object first and is blocked, the distal finger segment will further rotate automatically to adapt to the different shapes and sizes of the object, achieving a relatively good enveloping grasping effect. Before contacting the object, when the proximal finger segment of the adaptive finger bends, the other finger segments do not rotate relative to the proximal finger segment, and the finger appears stiff in the middle of the grasping process. In addition, the finger does not have a good end-holding function. Since flat clamping fingers, coupled fingers, and adaptive fingers all show limitations in movement, a new composite finger is needed that can use fewer drive mechanisms to make the gathering more flexible and have a better clamping effect. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a compound displacement robot finger device that can clamp a workpiece more flexibly.

[0004] The present invention also provides a robot hand device.

[0005] According to the first aspect of the present invention, a compound displacement robot finger device and a robot hand device are used to grasp a workpiece. The compound displacement robot finger device includes: a base; a first finger joint, the first finger joint is rotatably connected to the base, and the first finger joint is used to clamp the workpiece; a second finger joint, the second finger joint is rotatably connected to the first finger joint, and the second finger joint is used to clamp the workpiece; a third finger joint, the third finger joint is rotatably connected to the second finger joint, and the third finger joint is used to clamp the workpiece; a first driving rod, the first driving rod is rotatably connected to the base; a first driving mechanism, the first driving mechanism is used to drive the first driving rod to rotate; a first transmission rod, the first transmission rod is rotatably connected to the first driving rod; a second transmission rod, one end of the second transmission rod is rotatably connected to the first transmission rod, and the other end of the second transmission rod is rotatably connected to the rotation connection between the first finger joint and the second finger joint; a third transmission rod, One end is connected to the third finger joint, and the other end of the third transmission rod is connected to the rotation connection of the first transmission rod and the second transmission rod; a second driving rod, the second driving rod is rotatably connected to the base; a second driving mechanism, the second driving mechanism is used to drive the second driving rod to rotate; a first limiting rod, one end of the first limiting rod is rotatably connected to the second driving rod, and the other end of the first limiting rod is rotatably connected to the second transmission rod to limit the movement trajectory of the second transmission rod; a second limiting rod, one end of the second limiting rod is rotatably connected to the base, and the other end of the second limiting rod is rotatably connected to the second finger joint to limit the movement trajectory of the connection point of the first finger joint and the second finger joint; the rotation axes of the first finger joint, the second finger joint, the third finger joint, the first driving rod, the second driving rod, the first transmission rod, the second transmission rod, the third transmission rod, the first limiting rod and the second limiting rod are parallel to each other when they rotate.

[0006] The compound displacement robot finger device according to the first embodiment of the present invention has at least the following beneficial effects: by setting the first driving rod and the second driving rod to drive in different directions, and by using the first limiting rod and the second limiting rod to limit the movement direction of the structure, the compound displacement robot finger device can clamp the workpiece more flexibly in more ways.

[0007] According to some embodiments of the present invention, the first driving mechanism includes a first driving motor, a transmission screw, a first torsion spring and a first transmission assembly. The rotating shaft of the first driving motor is fixedly connected to the transmission screw to drive the transmission screw to rotate. The transmission screw drives the first torsion spring to rotate. The rotation of the first torsion spring drives the first transmission assembly. The first transmission assembly drives the first driving rod to rotate.

[0008] According to some embodiments of the present invention, the connection point between the first finger joint and the base is point A, the connection point between the first finger joint and the second finger joint is point B, the second driving rod is rotatably connected to the base at point A, the connection point between the second driving rod and the first limiting rod is point F, and the connection point between the first limiting rod and the second transmission rod is point G. When the second driving mechanism drives the second driving rod to rotate to the first side of the line segment AB, the line segment AB is parallel to the line segment FG, and the line segment AF is parallel to the line segment BG.

[0009] According to some embodiments of the present invention, the second driving mechanism includes a second driving motor, a first limit block, a second transmission assembly and a second torsion spring, the transmission shaft of the second driving motor drives the second torsion spring to rotate, the second torsion spring drives the second transmission assembly, the second transmission assembly drives the second driving rod to rotate, and the first limit block is arranged on the first side of the line segment AB and is used to limit the rotation angle of the second driving rod.

[0010] According to some embodiments of the present invention, the second driving mechanism further includes a second limit block, which is used to limit the rotation angle of the second driving rod. The second limit block is arranged on the second side of the line segment AB. When the second driving mechanism drives the second driving rod to rotate to the second side of the line segment AB, the line segment AB intersects with the line segment GF.

[0011] According to some embodiments of the present invention, the first transmission rod, the second transmission rod and the third transmission rod are all rotatably connected at point H, the second transmission rod and the first finger joint are rotatably connected at point B, the H point is on the extension line of the line segment BG, the connection point between the second finger joint and the third finger joint is point C, the connection point between the third transmission rod and the third finger joint is point I, the line segment BH is parallel to the line segment CI, and the line segment HI is parallel to the line segment BC.

[0012] According to some embodiments of the present invention, the connection point between the second limiting rod and the base is point D, the connection point between the second limiting rod and the second finger joint is point E, and the length relationship between line segment AD, line segment DE, line segment BE, line segment BC, line segment EC and line segment AB satisfies: AD:DE:BE:BC:CE:AB=68:51:49:68:110:100.

[0013] According to some embodiments of the present invention, a knuckle pad is provided on a side of the first knuckle, the second knuckle, and the third knuckle close to the workpiece, and the knuckle pad is used to abut against the workpiece.

[0014] According to some embodiments of the present invention, a normal direction of a surface of the knuckle pad on the third knuckle that contacts the workpiece is parallel to the line segment CI.

[0015] A robot hand device according to an embodiment of the second aspect of the present invention includes the compound displacement robot finger device according to any one of the above embodiments.

[0016] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0018] Figure 1 A schematic diagram of the internal structure of a compound displacement robot finger device according to an embodiment of the present invention;

[0019] Figure 2 This is a front structural diagram of a compound displacement robot finger device according to one embodiment of the present invention;

[0020] Figure 3 A schematic side structural diagram of a compound position-shifting robot finger device according to an embodiment of the present invention;

[0021] Figure 4 A schematic cross-sectional view of a finger device of a compound displacement robot according to an embodiment of the present invention;

[0022] Figure 5 Schematic diagram of the point C translation principle in one embodiment of the present invention;

[0023] Figure 6 Schematic diagram of the principle of switching of the second driving rod between the first limit block and the second limit block in one embodiment of the present invention;

[0024] Figure 7 A schematic structural diagram of a second driving rod switching between a first limit block and a second limit block in one embodiment of the present invention;

[0025] Figure 8 Schematic diagram of the principle of translation of the third finger joint in one embodiment of the present invention;

[0026] Figure 9 This is a schematic structural diagram of the translation of the third finger joint in one embodiment of the present invention;

[0027] Figure 10 A schematic diagram of the principle of adaptive grasping of a straight flat clamp in one embodiment of the present invention;

[0028] Figure 11A schematic diagram of coupling clamping in one embodiment of the present invention;

[0029] Figure 12 A schematic diagram of the principle of coupled clamping and adaptive grasping in one embodiment of the present invention;

[0030] Figure 13 This is a schematic diagram of the structure of a compound displacement robot finger device clamping a workpiece in one embodiment of the present invention.

[0031] Reference numerals:

[0032] 11. First finger joint; 12. Second finger joint; 13. Third finger joint; 21. First limiting rod; 22. Second limiting rod; 31. First transmission rod; 32. Second transmission rod; 33. Third transmission rod; 41. First drive rod; 42. Second drive rod; 5. First drive mechanism; 51. First drive motor; 52. Drive screw; 53. First torsion spring; 54. First transmission assembly; 6. Second drive mechanism; 61. Second drive motor; 62. First limit block; 63. Second transmission assembly; 64. Second torsion spring; 65. Second limit block; 7. Workpiece; 8. Base. DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of the present invention, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 4 , a compound displacement robot finger device and a robot hand device according to a first embodiment of the present invention are used to grasp a workpiece 7. The compound displacement robot finger device includes: a base 8, a first finger joint 11, a second finger joint 12, a third finger joint 13, a first driving rod 41, a first driving mechanism 5, a first transmission rod 31, a second transmission rod 32, a third transmission rod 33, a second driving rod 42, a second driving mechanism 6, a first limiting rod 21 and a second limiting rod 22. The first finger joint 11 is rotatably connected to the base 8, and the first finger joint 11 is used to clamp the workpiece 7; the second finger joint 12 is rotatably connected to the first finger joint 11, and the second finger joint 12 is used to clamp the workpiece 7; the third finger joint 13 is rotatably connected to the second finger joint 12, and the third finger joint 13 is used to clamp the workpiece 7; the first driving rod 41 is rotatably connected to the base 8; the first driving mechanism 5 is used to drive the first driving rod 41 to rotate; the first transmission rod 31 is rotatably connected to the first driving rod 41; one end of the second transmission rod 32 is rotatably connected to the first transmission rod 31, and the other end of the second transmission rod 32 is rotatably connected to the first transmission rod 31 The end is rotatably connected to the rotation connection of the first finger joint 11 and the second finger joint 12; one end of the third transmission rod 33 is connected to the third finger joint 13, and the other end of the third transmission rod 33 is connected to the rotation connection of the first transmission rod 31 and the second transmission rod 32; the second driving rod 42 is rotatably connected to the base 8; the second driving mechanism 6 is used to drive the second driving rod 42 to rotate; one end of the first limiting rod 21 is rotatably connected to the second driving rod 42, and the other end of the first limiting rod 21 is rotatably connected to the second transmission rod 32 to limit the movement trajectory of the second transmission rod 32; one end of the second limiting rod 22 is rotatably connected to the base 8, and the other end of the second limiting rod 22 is rotatably connected to the second finger joint 12 to limit the movement trajectory of the connection point between the first finger joint 11 and the second finger joint 12; the rotation axes of the first finger joint 11, the second finger joint 12, the third finger joint 13, the first driving rod 41, the second driving rod 42, the first transmission rod 31, the second transmission rod 32, the third transmission rod 33, the first limiting rod 21 and the second limiting rod 22 are parallel to each other when they rotate.

[0038] When the workpiece 7 is clamped in a straight line, the first driving rod 41 is driven by the first driving mechanism 5, and the second driving rod 42 is driven to rotate by the second driving mechanism 6. The first driving rod 41 drives the first transmission rod 31 to rotate, and the second driving rod 42 drives the first limiting rod 21 to move. At this time, the second transmission rod 32 is driven by the first transmission rod 31 and the first limiting rod 21, so that the second transmission rod 32 drives the first finger joint 11, and drives the second finger joint 12 through the first finger joint 11. At the same time, the trajectory of the second finger joint 12 is restricted by the second limiting rod 22, and the third finger joint 13 is restricted by the third transmission rod 33, so that the third finger joint 13 can move along an approximately straight line trajectory, thereby performing straight line clamping.

[0039] Reference Figure 5 Specifically, the connection point between the first finger joint 11 and the base 8 is point A, the connection point between the first finger joint 11 and the second finger joint 12 is point B, the second drive rod 42 is rotationally connected to the base 8 at point A, the connection point between the second drive rod 42 and the first limiting rod 21 is point F, and the connection point between the first limiting rod 21 and the second transmission rod 32 is point G. When the second drive mechanism 6 drives the second drive rod 42 to rotate to the first side of line segment AB, line segment AB is parallel to line segment FG, and line segment AF is parallel to line segment BG. The first transmission rod 31, the second transmission rod 32, and the third transmission rod 33 are all rotationally connected at point H. The second transmission rod 32 and the first finger joint 11 are rotationally connected at point B. Point H is on the extension line of line segment BG. The connection point between the second finger joint 12 and the third finger joint 13 is point C. The connection point between the third transmission rod 33 and the third finger joint 13 is point I. Line segment BH is parallel to line segment CI, and line segment HI is parallel to line segment BC. Line segments AB, FG, AF, and BG are arranged into a parallelogram. The angle of the second drive rod 42 limited by the second drive mechanism 6 is the angle of the second transmission rod 32. Maintaining the angle of the second drive rod 42 constant also maintains the angle of the second transmission rod 32. By arranging line segments BH, CI, HI, and BC into a parallelogram, line segment CI on the third phalanx 13 remains parallel to line segment BG, i.e., line segment AF. Thus, the rotation angle of the first phalanx 11 can be controlled by controlling the angle of the second drive rod 42. By driving the first drive rod 41 to rotate, the third phalanx 13 is driven by the first transmission rod 31 and the third transmission rod 33, and the third phalanx 13 is constrained by the second limiting rod 22, the first phalanx 11, and the second phalanx 12, so that the third phalanx 13 moves approximately linearly at a fixed angle.

[0040] Specifically, the connection point between the second limiting rod 22 and the base 8 is point D, and the connection point between the second limiting rod 22 and the second finger joint 12 is point E. The length relationship between line segments AD, DE, BE, BC, EC, and AB satisfies the following: AD:DE:BE:BC:CE:AB = 68:51:49:68:110:100. The transmission structure formed by the second limiting rod 22, the second finger joint 12, and the first finger joint 11 causes the connection point C between the second finger joint 12 and the third finger joint 13 to move approximately linearly.

[0041] In summary, the transmission structure formed by the second limiting rod 22, the second finger joint 12, and the first finger joint 11 restricts the motion trajectory of point C to a nearly straight line. The second driving rod 42 then controls the rotation angle of the third finger joint 13 via two parallelograms: the parallelogram formed by line segments BH, CI, HI, and BC, and the parallelogram formed by line segments AB, FG, AF, and BG. This allows the first driving rod 41, after being driven by the first transmission rod 31, the second transmission rod 32, and the third transmission rod 33, to clamp the third finger joint 13 along an approximately straight line.

[0042] Reference Figure 8 and Figure 9 In the process of linear flat clamping, the third finger joint 13 is used to clamp the workpiece 7. If the first finger joint 11 or the second finger joint 12 touches the workpiece 7 first, it will automatically switch to linear flat clamping adaptive grasping. Taking the first finger joint 11 as an example of linear contact with the workpiece 7, when the workpiece 7 blocks the first finger joint 11 from rotating, the first drive rod 41 cannot drive the first transmission rod 31 to rotate, that is, the first drive rod 41 is fixed. At this time, the second drive rod 42 is rotated so that the first drive rod 41 can continue to rotate, so that the first transmission rod 31 and the second transmission rod 32 can continue to rotate, that is, point H rotates with point B as the center of the circle. After the first finger joint 11 is fixed, due to the action of the second limiting rod 22, point C is fixed. At this time, the third finger joint 13 rotates with point C as the center of the circle until the third finger joint 13 clamps the workpiece 7.

[0043] Furthermore, the second drive mechanism 6 includes a second drive motor 61, a first limit block 62, a second transmission assembly 63, and a second torsion spring 64. The drive shaft of the second drive motor 61 drives the second torsion spring 64 to rotate, the second torsion spring 64 drives the second transmission assembly 63, and the second transmission assembly 63 drives the second drive rod 42 to rotate. The first limit block 62 is arranged on the first side of the line segment AB and is used to limit the rotation angle of the second drive rod 42. When the workpiece 7 is clamped flat, that is, when the second drive rod 42 needs to remain stationary, the second drive motor 61 drives the torsion spring, and the torsion spring presses the second drive rod 42 against the first limit block 62. When the first knuckle 11 is fixed against the workpiece 7, the first drive rod 41 continues to rotate, causing the second drive rod 42 to squeeze the second torsion spring 64, causing the second drive rod 42 to rotate.

[0044] Reference Figure 6 and Figure 7 The second driving mechanism 6 also includes a second limit block 65, which is used to limit the rotation angle of the second driving rod 42. The second limit block 65 is set on the second side of the line segment AB. When the second driving mechanism 6 drives the second driving rod 42 to rotate to the second side of the line segment AB, the line segment AB intersects with the line segment GF.

[0045] When the workpiece 7 needs to be coupled and clamped, the second driving mechanism 6 drives the second driving rod 42 to rotate to the second side of the line segment AB so that it abuts against the second stopper 65, causing the line segment AB to intersect the line segment GF. At this time, the parallelogram formed by the line segments AB, FG, AF, and BG is broken.

[0046] Reference Figure 10 、 Figure 11 、 Figure 12 and Figure 13 When the first drive rod 41 rotates to drive the first transmission rod 31, the first limiting rod 21 and the first finger joint 11 constrain the second transmission rod 32. As the first finger joint 11 rotates, the second transmission rod 32 also rotates at a certain angle relative to the first finger joint 11. At this time, the second finger joint 12 rotates at a certain angle under the constraint of the second limiting rod 22. Simultaneously, the parallelogram formed by line segments BH, CI, HI, and BC causes line segment CI to rotate at a certain angle, thereby rotating the third finger joint 13. At this point, the first finger joint 11, the second finger joint 12, and the third finger joint 13 all clamp the workpiece 7 at a certain proportional rotation angle.

[0047] During the coupled clamping process, if the first knuckle 11 or the second knuckle 12 first touches the workpiece 7, it automatically switches to coupled clamping adaptive gripping. Taking the first knuckle 11 as an example, when the first knuckle 11 is abutted and fixed on the workpiece 7, the first drive rod 41 cannot be used to drive the first transmission rod 31 to rotate, that is, the first drive rod 41 is fixed. At this time, the second drive rod 42 is rotated, so that the first drive rod 41 can continue to rotate, so that the first transmission rod 31 and the second transmission rod 32 can continue to rotate, that is, point H rotates with point B as the center of the circle, and at this time drives the second knuckle 12 and the third knuckle 13 to rotate until the first knuckle 11, the second knuckle 12 and the third knuckle 13 all abut on the workpiece 7.

[0048] Furthermore, the first drive mechanism 5 includes a first drive motor 51, a drive screw 52, ​​a first torsion spring 53, and a first transmission assembly 54. The rotation shaft of the first drive motor 51 is fixedly connected to the drive screw 52 to drive the drive screw 52 to rotate. The drive screw 52 drives the first torsion spring 53 to rotate. The rotation of the first torsion spring 53 drives the first transmission assembly 54. The first transmission assembly 54 drives the first drive rod 41 to rotate. When the first finger joint 11 is fixed against the workpiece 7, the first drive rod 41 continues to rotate, causing the second drive rod 42 to squeeze the second torsion spring 64, causing the second drive rod 42 to rotate, thereby continuing to drive the second finger joint 12 and the third finger joint 13 to rotate.

[0049] According to some embodiments of the present invention, knuckle pads are provided on the side of the first knuckle 11, the second knuckle 12, and the third knuckle 13 close to the workpiece 7, and the knuckle pads are used to abut against the workpiece 7. The knuckle pads can more firmly clamp the workpiece 7, and by setting the angles of the knuckle pads, the first knuckle 11, the second knuckle 12, and the third knuckle 13 can clamp the workpiece 7 at a more appropriate angle.

[0050] According to some embodiments of the present invention, the normal of the surface where the knuckle pad on the third knuckle 13 contacts the workpiece 7 is parallel to the line segment CI. In this case, the second drive rod 42 can better control the contact angle between the third knuckle 13 and the workpiece 7. That is, when the second drive rod 42 is in the horizontal direction and contacts the first limit block 62, the contact direction between the third knuckle 13 and the workpiece 7 is horizontal. That is, when the second drive rod 42 is on the first side of the line segment AB, the direction of the second drive rod 42 is the contact direction between the third knuckle 13 and the workpiece 7.

[0051] A robot hand device according to an embodiment of the second aspect of the present invention includes the compound displacement robot finger device of any one of the above embodiments.

[0052] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Claims

1. A compound displacement robot finger device, characterized in that: For grasping workpieces, the compound position-shifting robot finger device comprises: base; a first finger joint, the first finger joint being rotatably connected to the base and being used for clamping the workpiece; a second finger joint, the second finger joint being rotatably connected to the first finger joint, and the second finger joint being used for clamping the workpiece; a third finger joint, the third finger joint being rotatably connected to the second finger joint, and the third finger joint being used for clamping the workpiece; a first driving rod, the first driving rod being rotatably connected to the base; a first driving mechanism, the first driving mechanism being used to drive the first driving rod to rotate; a first transmission rod, the first transmission rod being rotatably connected to the first driving rod; a second transmission rod, one end of the second transmission rod being rotatably connected to the first transmission rod, and the other end of the second transmission rod being rotatably connected to a rotatable connection between the first and second finger joints; a third transmission rod, one end of the third transmission rod being connected to the third finger joint, and the other end of the third transmission rod being connected to the rotation connection between the first transmission rod and the second transmission rod; a second driving rod, the second driving rod being rotatably connected to the base; a second driving mechanism, the second driving mechanism being used to drive the second driving rod to rotate; a first limiting rod, one end of which is rotatably connected to the second driving rod, and the other end of which is rotatably connected to the second transmission rod, so as to limit the motion trajectory of the second transmission rod; a second limiting rod, one end of which is rotatably connected to the base, and the other end of which is rotatably connected to the second finger joint, so as to limit the motion trajectory of the connection point between the first finger joint and the second finger joint; The rotation axes of the first finger joint, the second finger joint, the third finger joint, the first driving rod, the second driving rod, the first transmission rod, the second transmission rod, the third transmission rod, the first limiting rod and the second limiting rod are parallel to each other when they rotate; The first driving mechanism includes a first driving motor, a transmission screw, a first torsion spring and a first transmission assembly. The rotating shaft of the first driving motor is fixedly connected to the transmission screw to drive the transmission screw to rotate. The transmission screw drives the first torsion spring to rotate. The rotation of the first torsion spring drives the first transmission assembly. The first transmission assembly drives the first driving rod to rotate. The connection point between the first finger joint and the base is point A, and the connection point between the first finger joint and the second finger joint is point B. The second driving mechanism includes a second driving motor, a first limit block, a second transmission assembly and a second torsion spring. The transmission shaft of the second driving motor drives the second torsion spring to rotate, the second torsion spring drives the second transmission assembly, and the second transmission assembly drives the second driving rod to rotate. The first limit block is arranged on the first side of the line segment AB and is used to limit the rotation angle of the second driving rod.

2. A compound displacement robot finger device according to claim 1, characterized in that: The second driving rod is rotatably connected to the base at point A, the connection point between the second driving rod and the first limiting rod is point F, and the connection point between the first limiting rod and the second transmission rod is point G. When the second driving mechanism drives the second driving rod to rotate to the first side of line segment AB, line segment AB is parallel to line segment FG, and line segment AF is parallel to line segment BG.

3. The compound displacement robot finger device according to claim 1, characterized in that: The second driving mechanism also includes a second limit block, which is used to limit the rotation angle of the second driving rod. The second limit block is set on the second side of the line segment AB. When the second driving mechanism drives the second driving rod to rotate to the second side of the line segment AB, the line segment AB intersects with the line segment GF.

4. The compound displacement robot finger device according to claim 2, characterized in that: The first transmission rod, the second transmission rod and the third transmission rod are all rotatably connected at point H, the second transmission rod and the first finger joint are rotatably connected at point B, point H is on the extension line of line segment BG, the connection point between the second finger joint and the third finger joint is point C, the connection point between the third transmission rod and the third finger joint is point I, line segment BH is parallel to line segment CI, and line segment HI is parallel to line segment BC.

5. The compound displacement robot finger device according to claim 4, characterized in that: The connection point between the second limiting rod and the base is point D, the connection point between the second limiting rod and the second finger joint is point E, and the length relationship between line segment AD, line segment DE, line segment BE, line segment BC, line segment EC and line segment AB satisfies: AD:DE:BE:BC:CE:AB=68:51:49:68:110:

100.

6. The compound displacement robot finger device according to claim 1, characterized in that: A knuckle pad is provided on a side of the first knuckle, the second knuckle and the third knuckle close to the workpiece, and the knuckle pad is used to abut against the workpiece.

7. The compound displacement robot finger device according to claim 4, characterized in that: The normal direction of the surface of the knuckle pad on the third knuckle that contacts the workpiece is parallel to the line segment CI.

8. A robotic hand device, characterized in that The composite displacement robot finger device comprises the compound displacement robot finger device according to any one of claims 1 to 7.

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