A direct-drive finger structure

Abstract

The present invention relates to the field of manipulator technology, and in particular to a direct-drive finger structure, including a finger assembly, and a first driver, a second driver, and a third driver including a planetary roller screw pair; the finger assembly includes a U-shaped universal joint, a bending transmission mechanism, and two sets of side-swing transmission mechanisms located on both sides of the bending transmission mechanism. In view of the technical problem that the existing mechanical finger structure has flexibility defects, the present invention designs a finger assembly composed of a bending transmission mechanism and two sets of side-swing transmission mechanisms, the input power of the finger assembly is realized by direct drive of three actuators, and the finger assembly can simulate the flexible bending and swinging of human fingers.

Description

Technical Field

[0001] The present invention relates to the technical field of manipulators, and in particular to a direct-drive finger structure. Background Art

[0002] Some traditional robot end effectors (i.e. manipulators) have design limitations on their palm and finger structures, resulting in a single overall grasping method and lack of flexibility.

[0003] For example, for an anthropomorphic manipulator, its flexibility is mainly restricted by the finger structure, that is, the gripping method or movement method of the manipulator is inevitably restricted by the layout of the finger structure. At present, most finger structures can only imitate the bending of human fingers, but cannot imitate the shaking of fingers, resulting in the inability to further improve the overall flexibility of the manipulator. Summary of the invention

[0004] In response to the technical problem that existing mechanical finger structures have flexibility defects, the present invention provides a direct-drive finger structure, which designs a finger assembly composed of a bending transmission mechanism and two sets of side-swing transmission mechanisms. The input power of the finger assembly is directly driven by three actuators. The finger assembly can simulate the flexible bending and swinging of human fingers.

[0005] The technical solution provided by the present invention is: a direct-drive finger structure, including a finger assembly, and a first driver, a second driver and a third driver including a planetary roller screw pair; the second driver and the third driver are located on the same side of the first driver and are arranged in parallel; a housing is fixedly provided on one side of the first driver, the second driver and the third driver, the planetary roller screw pair includes rollers, nuts and screws meshed in sequence, the nuts constitute the output ends of the first driver, the second driver and the third driver, and the housing is used to limit the rotation of the nuts; the nuts of the first driver, the second driver and the third driver are respectively fixedly provided with The first connecting tooling, the second connecting tooling and the third connecting tooling are all inclined and extended toward the side of the centripetal bend of the finger assembly; the finger assembly includes a U-shaped universal joint, a bending transmission mechanism and two sets of side-swing transmission mechanisms located on both sides of the bending transmission mechanism, the U-shaped universal joint includes a rotating shaft fixed in the middle, and a first hinge part and a second hinge part located on both sides of the opening, and the U-shaped universal joint is rotatably connected to the shell through the rotating shaft; the bending transmission mechanism includes a first connecting rod, a second connecting rod, a side-swing connecting rod, a third connecting rod, a fourth connecting rod and a fingertip seat; the fourth connecting rod is provided with a coupling connection part , the fingertip seat is provided with a first connection part, a second connection part and a third connection part arranged in a triangle; the side-swing transmission mechanism includes a first sub-connecting rod, a second sub-connecting rod and a third sub-connecting rod; one end of the first connecting rod is connected to the first connecting tooling through a joint bearing, the other end of the first connecting rod is universally connected with the side-swing connecting rod through the second connecting rod, one end of the third connecting rod is hinged to the side-swing connecting rod, the other end of the third connecting rod is hinged to the fourth connecting rod, and the fourth connecting rod is hinged to the first connection part; the first sub-connecting rods of the two groups of the side-swing transmission mechanisms are respectively connected to the second connecting tooling and the third connecting tooling through joint bearings A pin rod is arranged between the first secondary connecting rods on both sides, the first secondary connecting rod and the second secondary connecting rod are connected to the pin rod through a joint bearing, and the side swing connecting rod is hinged to the middle part of the pin rod; the second secondary connecting rod includes a support rod and a coupling rod, one end of the support rod at two places is hinged to the pin rod, and the first hinge part and the second hinge part are respectively hinged to the other end of the support rod at two places; the coupling rod includes a first transmission connection part and a second transmission connection part, the first transmission connection part is hinged to the third secondary connecting rod, the second transmission connection part is hinged to the coupling connection part, and the second connection part and the third connection part are respectively hinged to the third secondary connecting rods at two places.The first driver, the second driver and the third driver all include a housing, in which a motor and the planetary roller screw pair are arranged; the planetary roller screw pair also includes a retaining frame, which is located between the nut and the screw, and the two ends of the roller are rotatably connected to the retaining frame respectively; the motor includes a stator and a rotor, the stator is arranged on the outside of the rotor and fixedly connected to the housing, and the screw is fixedly connected to the rotor; a tension and pressure sensor is arranged on the end of the housing away from the nut, a rotary encoder is arranged between the screw and the housing, a linear displacement sensor is arranged between the nut and the inner wall of the shell, a control unit is arranged in the housing, and the motor, the linear displacement sensor, the rotary encoder and the tension and pressure sensor are all electrically connected to the control unit.

[0006] Optionally, the angle formed by the first connecting tool and the horizontal end face of the nut is recorded as a1; the angle formed by the second connecting tool and the horizontal end face of the nut is equal to the angle formed by the third connecting tool and the horizontal end face of the nut and is recorded as a2; wherein the values ​​of a1 and a2 are 35°-45°.

[0007] Optionally, the second link and the side swing link are hinged to form a first rotation pair R1, the third link and the side swing link are hinged to form a second rotation pair R2, and the side swing link and the pin rod are hinged to form a third rotation pair R3; the lines connecting the rotation centers of the first rotation pair R1, the second rotation pair R2 and the third rotation pair R3 form line segments d1, line segments d2 and line segments d3, and the line segments d1, d2 and d3 form an obtuse triangle; wherein the angle formed by the line connecting the first rotation pair R1 and the second rotation pair R2 and the line connecting the second rotation pair R2 and the third rotation pair R3 is 110°-120°.

[0008] Optionally, the third connecting rod is hinged with the fourth connecting rod to form a fourth rotation pair R4, the fourth connecting rod is hinged with the first connecting part to form a fifth rotation pair R5, and the second transmission connecting part is hinged with the coupling connecting part to form a sixth rotation pair R6; the rotation centers of the fourth rotation pair R4, the fifth rotation pair R5 and the sixth rotation pair R6 are connected in pairs to form line segments d4, line segments d5 and line segments d6, and the line segments d4, d5 and d6 form an obtuse triangle; wherein, the fourth rotation pair R4 and The angle formed by the line connecting the fifth rotation pair R5 and the line connecting the fifth rotation pair R5 and the sixth rotation pair R6 is 10°-20°, the angle formed by the line connecting the fourth rotation pair R4 and the sixth rotation pair R6 and the line connecting the fifth rotation pair R5 and the sixth rotation pair R6 is 50°-55°, and the angle formed by the line connecting the fourth rotation pair R4 and the sixth rotation pair R6 and the line connecting the fourth rotation pair R4 and the fifth rotation pair R5 is 110°-120°.

[0009] Optionally, a center line connecting the first transmission connection portion and the second transmission connection portion on the coupling rod is perpendicular to an extension direction of a main body of the coupling rod.

[0010] Optionally, the angle between the support rod and the coupling rod in the second secondary connecting rod is 45°.

[0011] Optionally, an arc-shaped curved structure is provided at a position of the third secondary connecting rod close to the first transmission connection portion, and a bending direction of the arc-shaped curved structure is consistent with a bending direction of the finger assembly.

[0012] Optionally, the rotary encoder includes a reading unit and a magnetic pole, a magnet sheath is fixedly provided at one end of the lead screw, the magnetic pole is fixedly provided on the magnet sheath, the magnetic pole is arranged opposite to the reading unit, and the reading unit is electrically connected to the control unit.

[0013] Optionally, a bearing is provided between the lead screw and the housing.

[0014] Beneficial Effects

[0015] The technical solution provided by the present invention has the following beneficial effects compared with the prior art: in view of the technical problem that the existing mechanical finger structure has flexibility defects, the present invention designs a finger assembly composed of a bending transmission mechanism and two sets of side-swing transmission mechanisms, and the input power of the finger assembly is directly driven by three actuators. The finger assembly can simulate the flexible bending and swinging of human fingers.

[0016] Furthermore, the direct-drive finger structure of the present invention has high flexibility while ensuring good rigidity and stability. The bending transmission mechanism and the two sets of side-swing transmission mechanisms are directly driven by three actuators respectively, which ensures a strong load-bearing capacity. When applied to a manipulator, the manipulator can have strong grasping flexibility and grasping stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is one of the structural schematic diagrams of a direct-drive finger structure proposed in an embodiment of the present invention.

[0018] Figure 2 This is a second structural schematic diagram of a direct-drive finger structure proposed in an embodiment of the present invention.

[0019] Figure 3 This is a third structural schematic diagram of a direct-drive finger structure proposed in an embodiment of the present invention.

[0020] Figure 4 This is a fourth structural schematic diagram of a direct-drive finger structure proposed in an embodiment of the present invention.

[0021] Figure 5 This is the fifth structural schematic diagram of a direct-drive finger structure proposed in an embodiment of the present invention.

[0022] Figure 6 This is a schematic diagram of the structure of the first driver, the second driver or the third driver proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0024] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the invention. It should also be noted that, for the convenience of description, only the parts related to the invention are shown in the accompanying drawings. The words "first", "second", etc. described in the present invention are set for the convenience of describing the technical solution of the present invention, and have no specific limiting effect. They are all general references and do not constitute a limiting effect on the technical solution of the present invention. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be a connection between the insides of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. Multiple technical solutions in the same embodiment, and multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions without contradictions or conflicts, all of which are within the scope of protection required by the present invention.

[0025] Combined with Figure 1-6 This embodiment proposes a direct-drive finger structure, including a finger assembly 1, and a first driver 21, a second driver 22, and a third driver 23 including a planetary roller screw pair. The second driver 22 and the third driver 23 are located on the same side of the first driver 21 and arranged side by side, so that the first driver 21, the second driver 22, and the third driver 23 form a triangle arrangement. Among them, the planetary roller screw pair can be a differential planetary roller screw pair or a circulating planetary roller screw pair.

[0026] A housing 3 is fixedly provided on one side of the first driver 21, the second driver 22 and the third driver 23. The planetary roller screw pair includes rollers 200, nuts 201 and screws 202 that are meshed in sequence. The nut 201 constitutes the output end of the first driver 21, the second driver 22 and the third driver 23. The housing 3 is used to limit the rotation of the nut 201, thereby ensuring that the nut 201 can make a linear motion along the extension direction of the screw 202.

[0027] The first connecting fixture 41, the second connecting fixture 42 and the third connecting fixture 43 are fixedly arranged on the nuts 201 of the first driver 21, the second driver 22 and the third driver 23, respectively, and the first connecting fixture 41, the second connecting fixture 42 and the third connecting fixture 43 are all inclined and extended to the side of the centripetal bending of the finger assembly 1. It can be understood that the purpose of the first connecting fixture 41, the second connecting fixture 42 and the third connecting fixture 43 being inclined to one side is that when the nut 201 moves linearly along the extension direction of the lead screw 202, the lead screw 202 will penetrate the nut 201, so as to avoid interference between the lead screw 202 and the first connecting fixture 41, the second connecting fixture 42, the third connecting fixture 43 or other structures.

[0028] The finger assembly 1 includes a U-shaped universal joint 5, a bending transmission mechanism and two sets of side-swing transmission mechanisms located on both sides of the bending transmission mechanism. Among them, the U-shaped universal joint 5 includes a rotating shaft 50 fixed in the middle, and a first hinge part and a second hinge part located on both sides of the opening, and the U-shaped universal joint 5 is rotatably connected to the housing 3 through the rotating shaft 50. The bending transmission mechanism includes a first connecting rod 111, a second connecting rod 112, a side-swing connecting rod 110, a third connecting rod 113, a fourth connecting rod 114 and a fingertip seat 115; a coupling connecting part is provided on the fourth connecting rod 114, and a first connecting part, a second connecting part and a third connecting part arranged in a triangle are provided on the fingertip seat 115. The side-swing transmission mechanism includes a first secondary connecting rod 121, a second secondary connecting rod 122 and a third secondary connecting rod 123.

[0029] One end of the first link 111 is connected to the first connecting fixture 41 through a joint bearing, the other end of the first link 111 is connected to the side swing link 110 through the second link 112 to form a universal connection, one end of the third link 113 is hinged to the side swing link 110, the other end of the third link 113 is hinged to the fourth link 114, and the fourth link 114 is hinged to the first connecting portion. The first link 111 is connected to the side swing link 110 through the second link 112 to form a universal connection, which means that the axis of the rotation center formed by the first link 111 and the second link 112 is perpendicular to the axis of the rotation center formed by the second link 112 and the side swing link 110.

[0030] The first auxiliary connecting rods 121 of the two sets of side-swing transmission mechanisms are movably connected to the second connecting fixtures 42 and the third connecting fixtures 43 respectively through joint bearings. A pin rod 130 is arranged between the first auxiliary connecting rods 121 on both sides. The first auxiliary connecting rod 121 and the second auxiliary connecting rod 122 are connected to the pin rod 130 through joint bearings. The side-swing connecting rod 110 is hinged to the middle part of the pin rod 130.

[0031] The second secondary connecting rod 122 includes a support rod 1221 and a coupling rod 1222, one end of the two support rods 1221 is hinged to the pin rod 130, and the first hinge part and the second hinge part are respectively hinged to the other end of the two support rods 1221; the coupling rod 1222 includes a first transmission connection part and a second transmission connection part, the first transmission connection part is hinged to the third secondary connecting rod 123, the second transmission connection part is hinged to the coupling connection part, and the second connection part and the third connection part are respectively hinged to the two third secondary connecting rods 123. In this paragraph, the meanings of "two support rods 1221" and "two third secondary connecting rods 123" are "two support rods 1221 in the two groups of side-swing transmission mechanisms on both sides of the bending transmission mechanism" and "two third secondary connecting rods 123 in the two groups of side-swing transmission mechanisms on both sides of the bending transmission mechanism".

[0032] It can be imagined that when the direct-drive finger structure of this embodiment is used to form a robot, a covering that imitates the shape of the finger can be set on the outside of the finger assembly 1. The covering can be made of a specific material, such as silicone or other soft materials, to provide the finger assembly 1 with the friction required for grasping.

[0033] Based on the above structural design, the operation of a direct-drive finger structure of this embodiment can be divided into bending and swinging (lateral swinging).

[0034] The principle of the bending action of the direct-drive finger structure is as follows: the first driver 21 is started, and the nut 201 on the first driver 21 moves linearly along the extension direction of the lead screw 202, and the side swing link 110 is driven to rotate around the pin 130 through the first link 111 and the second link 112. While the side swing link 110 rotates, the third link 113 undergoes a compound motion of translation and rotation, and drives the fourth link 114 to move. At this time, the fourth link 114 will rotate with the second transmission connection as the rotation center, thereby driving the fingertip seat 115 to rotate. During the above movement process, the third secondary link 123 will undergo a compound motion of translation and rotation. It is precisely because the third secondary link 123 is connected to the second secondary link 122 and the fingertip seat 115 that a reverse force is provided (or it can be considered to provide a corresponding constraint), thereby ensuring the synchronous bending of the third link 113, the fourth link 114 and the fingertip seat 115.

[0035] As for the swinging action of the direct-drive finger structure, the principle is as follows: when the direct-drive finger structure is in any bending process, the second driver 22 or the third driver 23 can be started to realize the swinging of the direct-drive finger structure. Taking the case where only the second driver 22 is started as an example, the nut 201 on the second driver 22 moves linearly along the extension direction of the lead screw 202. Due to the setting of the joint bearing, the movement of the first sub-connecting rod 121 will drive the pin 130 to swing. It should be noted that the swinging of the pin 130 means that, relative to the horizontal state maintained by the pin 130 at the beginning, the two ends of the pin 130 present a high and low state during the swinging. When only the second driver 22 is started, the swinging of the pin 130 is a swinging that occurs with the end of the pin 130 away from the second driver 22 as the center. At this time, the support rod 1221 will be driven to move, and the U-shaped universal joint 5 will rotate around the rotating shaft 50 at the same time. The side swing link 110 will also tilt to one side with the swing of the pin rod 130, driving the third link 113, the fourth link 114 and the fingertip seat 115 connected thereto to tilt. The first link 111 and the second link 112 will also move relative to each other through the universal structure therebetween. The coupling rod 1222 will tilt with the support rod 1221, and will further drive the third sub-link 123 to pull the fourth link 114 and the fingertip seat 115 to tilt, thereby realizing the swinging action of the direct-drive finger structure.

[0036] It should be noted that the activation of the second driver 22 or the third driver 23 only affects the swing direction or swing amplitude of the direct-drive finger structure, and the driving principles of the two for the side-swing transmission mechanism are consistent. Generally, only one of the second driver 22 and the third driver 23 is activated. When the second driver 22 and the third driver 23 are activated at the same time, there are the following two situations:

[0037] When the nuts 201 on the second driver 22 and the third driver 23 move in opposite directions, combined with the aforementioned swinging motion principle, it can be seen that this will mainly affect the swinging motion of the pin 130, causing the height change at both ends of the pin 130 to intensify, that is, the speed or amplitude of the swinging motion can be intensified to a certain extent.

[0038] When the nuts 201 on the second driver 22 and the third driver 23 move in the same direction, it is generally applied to the bending action of the direct-drive finger structure. At this time, the first driver 21 must be started, and at this time, the second driver 22 and the third driver 23 generally move synchronously. The synchronous movement of the nuts 201 on the second driver 22 and the third driver 23 will drive the pin 130 to translate while maintaining a horizontal state (that is, the two ends of the pin 130 are not in a state of one high and one low during the movement), so that the side swing link 110 rotates relative to the pin 130. It can be understood that the rotation of the side swing link 110 relative to the pin 130 can actually be understood as the hinge part of the side swing link 110 and the pin 130, and the hinge part of the side swing link 110 and the second link 112. The relative height of these two hinge parts changes, so as long as the relative height of these two hinge parts is changed, the bending of the finger structure can be achieved.

[0039] For the first connecting fixture 41, the second connecting fixture 42 and the third connecting fixture 43 in this embodiment, the purpose of the inclined design has been described above, which is to avoid interference. It is conceivable that the inclination angles of the first connecting fixture 41, the second connecting fixture 42 and the third connecting fixture 43 will affect the length of the overall direct-drive finger structure, or other appearance features. Further, in a preferred embodiment, the angle formed by the first connecting fixture 41 and the horizontal end surface of the nut 201 is recorded as a1; the angle formed by the second connecting fixture 42 and the horizontal end surface of the nut 201 is equal to the angle formed by the third connecting fixture 43 and the horizontal end surface of the nut 201 and is recorded as a2; wherein the values ​​of a1 and a2 are 35°-45°. At this time, the inclination degree of the first connecting fixture 41, the second connecting fixture 42 and the third connecting fixture 43 is limited, which can not only ensure the stability and reliability of the transmission, but also make the direct-drive finger structure more compact as a whole, and can ensure that the appearance of the direct-drive finger structure is more beautiful and harmonious.

[0040] In other embodiments, the second link 112 is hinged with the side swing link 110 to form a first rotation pair R1, the third link 113 is hinged with the side swing link 110 to form a second rotation pair R2, and the side swing link 110 is hinged with the pin 130 to form a third rotation pair R3. The lines connecting the rotation centers of the first rotation pair R1, the second rotation pair R2 and the third rotation pair R3 form line segments d1, line segments d2 and line segments d3, and the line segments d1, line segments d2 and line segments d3 form an obtuse triangle. Among them, the angle formed by the line connecting the first rotation pair R1 and the second rotation pair R2 and the line connecting the second rotation pair R2 and the third rotation pair R3 is 110°-120°. In this embodiment, the side swing link 110 is improved and designed, and its structure can be equivalent to an obtuse triangle. This obtuse triangle and its angle design help the bending transmission mechanism solve the dead point problem, thereby avoiding the bending transmission mechanism from getting stuck during the stroke, making the movement of the bending transmission mechanism smoother.

[0041] And, in another embodiment, the third connecting rod 113 and the fourth connecting rod 114 are hinged to form a fourth rotation pair R4, the fourth connecting rod 114 and the first connecting part are hinged to form a fifth rotation pair R5, and the second transmission connecting part and the coupling connecting part are hinged to form a sixth rotation pair R6. The rotation centers of the fourth rotation pair R4, the fifth rotation pair R5 and the sixth rotation pair R6 are connected in pairs to form line segments d4, line segments d5 and line segments d6, and line segments d4, line segments d5 and line segments d6 form an obtuse triangle. Among them, the angle formed by the line connecting the fourth rotation pair R4 and the fifth rotation pair R5 and the line connecting the fifth rotation pair R5 and the sixth rotation pair R6 is 10°-20°, the angle formed by the line connecting the fourth rotation pair R4 and the sixth rotation pair R6 and the line connecting the fifth rotation pair R5 and the sixth rotation pair R6 is 50°-55°, and the angle formed by the line connecting the fourth rotation pair R4 and the sixth rotation pair R6 and the line connecting the fourth rotation pair R4 and the fifth rotation pair R5 is 110°-120°. This embodiment improves the design of the fourth connecting rod 114, and its structure can be equivalent to an obtuse triangle. This obtuse triangle and its angle design also help the bending transmission mechanism solve the dead point problem, thereby avoiding the bending transmission mechanism from getting stuck during the stroke, making the movement of the bending transmission mechanism smoother.

[0042] Similar to the above two embodiments, there are other embodiments to solve the dead point problem of the bending transmission mechanism or to ensure that the bending transmission mechanism moves more stably and smoothly. For example, the center line of the first transmission connection part and the second transmission connection part on the coupling rod 1222 can be designed to be perpendicular to the extension direction of the main part of the coupling rod 1222. The angle between the support rod 1221 and the coupling rod 1222 can also be designed to be 45°.

[0043] In addition, in another embodiment, the third secondary connecting rod 123 is provided with an arc-shaped bending structure near the first transmission connection portion, and the bending direction of the arc-shaped bending structure is consistent with the bending direction of the finger assembly 1. This structural design is also to ensure that the third secondary connecting rod 123 is prevented from getting stuck when cooperating with the bending transmission mechanism.

[0044] Combined with the above description, it can be seen that the direct-drive finger structure of this embodiment is actually an integrated connecting rod drive mechanism, which can realize the coordinated movement of multiple joints while maintaining the compactness of the structure and the efficient transmission of power. The direct-drive finger structure is composed of a finger assembly 1 including a bending transmission mechanism and a side-swing transmission mechanism, a first driver 21, a second driver 22 and a third driver 23, forming a modular design so that each part can be replaced or upgraded independently. Overall, compared with the existing finger structure, the direct-drive finger structure has a higher degree of freedom, which enables it to perform complex and delicate operations, especially when it is used in a manipulator, it can make the manipulator have better flexibility and precision, and can ensure a certain load capacity.

[0045] Furthermore, when the direct-drive finger structure of this embodiment is used to form a robot that simulates a human hand, that is, the thumb, index finger, middle finger, ring finger and little finger of the robot all adopt the direct-drive finger structure of this embodiment, and the arrangement of each finger is basically the same as that of a human hand, the robot can have a high flexibility of 15 degrees of freedom.

[0046] The design of this manipulator can more accurately simulate the complex movements of the human hand. For example, when grasping irregular objects, each finger can achieve synergy through different degrees of freedom and can coordinate adjustments during the grasping process. For example, when grasping a special-shaped object, the fingers can bend and twist at different angles, and follow the adjustment of the object's posture during the grasping process to adjust the posture of each finger to adapt to the contour of the special-shaped object. Traditional manipulators with low degrees of freedom are difficult to achieve such delicate operations.

[0047] In addition, the 15-DOF manipulator has higher operating accuracy. In some delicate operation scenarios, such as the assembly of electronic components, the 15-DOF manipulator can provide sufficient movement changes to cope with electronic components of different shapes and sizes, accurately grasp tiny parts, and can stably transfer parts to subsequent process operations such as parts welding. In short, the 15-DOF manipulator has strong adaptability in grasping objects. The independent degrees of freedom of each finger can be adjusted to achieve flexible adjustment of the manipulator as a whole, so as to perform grasping actions with appropriate strength and posture.

[0048] Combined with Figure 6, a direct-drive finger structure of this embodiment can be improved as follows compared with the technical solution of embodiment 1: the first driver 21, the second driver 22 and the third driver 23 all include a housing 203, and a motor and a planetary roller screw pair are arranged in the housing 203. The planetary roller screw pair also includes a retaining frame 204, and the retaining frame 204 is located between the nut 201 and the screw 202, and the two ends of the roller 200 are respectively rotatably connected to the retaining frame 204. The setting of the retaining frame 204 in this embodiment can be used to ensure the stability of the setting of the roller 200, and can ensure that the planetary roller screw pair moves efficiently, accurately and stably.

[0049] The motor includes a stator 205 and a rotor 206. The stator 205 is arranged outside the rotor 206 and fixedly connected to the housing 203. The lead screw 202 is fixedly connected to the rotor 206. A tension and pressure sensor is arranged at one end of the housing 203 away from the nut 201. A rotary encoder is arranged between the lead screw 202 and the housing 203. A linear displacement sensor is arranged between the nut 201 and the inner wall of the housing 3. A control unit is arranged in the housing 203. The motor, the linear displacement sensor, the rotary encoder and the tension and pressure sensor are all electrically connected to the control unit.

[0050] For the planetary roller screw pair of this embodiment, threads are processed inside the nut 201, and threads are processed on the screw 202. Combined with the structural form described above, its main working principle is: the control unit controls the motor to drive the screw 202 in the planetary roller screw pair to rotate, and the nut 201 in the planetary roller screw pair converts the rotational motion of the screw 202 into linear motion, driving the nut 201 to translate, thereby realizing the output of linear motion.

[0051] The movement of the lead screw 202 is controlled by a motor, and the motor is controlled by a control unit. The rotary encoder on the control unit can output the number of rotations of the lead screw 202 to the control unit, the linear displacement sensor can output the linear movement of the nut 201 to the control unit, and the tension and pressure sensor can output the tension and pressure received to the control unit. Among them, the rotary encoder and the linear displacement sensor are jointly arranged on the planetary roller screw pair, so synchronous operation is achieved, and both the rotary encoder and the linear displacement sensor can adopt an absolute value control method.

[0052] Therefore, the control unit can control the movement of the nut 201 in combination with the input information of the rotary encoder, the linear displacement sensor and the tension and pressure sensor, and further control the movement of the direct-drive finger structure.

[0053] In this embodiment, the motor is preferably a frameless torque motor. The stator 205 of the motor can drive the rotor 206 of the motor to drive the lead screw 202 to rotate, thereby driving the nut 201 to perform linear motion. That is, the motor rotor 206 is directly fixed on the lead screw 202, and is directly connected to the lead screw 202, effectively avoiding the gear reduction mechanism in the middle, effectively improving the integration of the structural layout, and reducing costs.

[0054] The preferred configuration of the rotary encoder is as follows: the rotary encoder includes a reading unit 207 and a magnetic pole 208, a magnet sheath 209 is fixedly disposed at one end of the lead screw 202, the magnetic pole 208 is fixedly disposed on the magnet sheath 209, the magnetic pole 208 is disposed opposite to the reading unit 207, and the reading unit 207 is electrically connected to the control unit. Thus, the magnetic pole 208 is directly fixed to the end of the lead screw 202, and the rotation data of the lead screw 202 can be accurately read.

[0055] In summary, the first driver 21, the second driver 22 and the third driver 23 adopted in this embodiment, by using a planetary roller screw pair, effectively shorten the lead and improve the load-bearing capacity while making the internal transmission structure more compact and improving the energy density; and adopting a design of direct connection between the motor and the screw 202, effectively improving the integration of the structural layout and reducing the cost.

[0056] Combining Examples 1 and 2, it can be seen that a direct-drive finger structure of this embodiment, through the design of the U-shaped universal joint 5, the bending transmission mechanism and the two sets of side-swing transmission mechanisms on both sides of the bending transmission mechanism, makes the finger assembly 1 part have high flexibility, that is, it can achieve bending and lateral swinging, and at the same time, this structural design ensures that the finger structure has good rigidity and stability. In addition, in the direct-drive finger structure, the first driver 21, the second driver 22 and the third driver 23 respectively form a direct-drive design with the bending transmission mechanism and the two sets of side-swing transmission mechanisms on both sides of the bending transmission mechanism, ensuring a strong load-bearing capacity. When applied to a manipulator, it can have strong grasping flexibility and grasping stability.

[0057] The above is a schematic description of the present invention and its implementation methods, which is not restrictive. The drawings show only one implementation method of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and creatively designs a structure and an embodiment similar to the technical solution without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A direct-drive finger structure, characterized in that: The invention comprises a finger assembly (1), and a first driver (21), a second driver (22), and a third driver (23) each including a planetary roller screw pair; the second driver (22) and the third driver (23) are located on the same side of the first driver (21) and are arranged in parallel; a housing (3) is fixedly provided on one side of the first driver (21), the second driver (22), and the third driver (23); the planetary roller screw pair comprises a roller (200), a nut (201), and a screw (202) that are meshed in sequence; the nut (201) constitutes an output end of the first driver (21), the second driver (22), and the third driver (23); and the housing (3) is used to limit the rotation of the nut (201); A first connecting fixture (41), a second connecting fixture (42) and a third connecting fixture (43) are fixedly mounted on the nuts (201) of the first driver (21), the second driver (22) and the third driver (23), respectively, and the first connecting fixture (41), the second connecting fixture (42) and the third connecting fixture (43) all extend obliquely toward a side of the finger assembly (1) that is bent centripetally; The finger assembly (1) comprises a U-shaped universal joint (5), a bending transmission mechanism, and two sets of side swing transmission mechanisms located on both sides of the bending transmission mechanism, the U-shaped universal joint (5) comprises a rotating shaft (50) fixed in the middle, and a first hinge part and a second hinge part located on both sides of an opening, and the U-shaped universal joint (5) is rotatably connected to the housing (3) via the rotating shaft (50); The bending transmission mechanism comprises a first connecting rod (111), a second connecting rod (112), a side swing connecting rod (110), a third connecting rod (113), a fourth connecting rod (114) and a fingertip seat (115); the fourth connecting rod (114) is provided with a coupling connecting portion, and the fingertip seat (115) is provided with a first connecting portion, a second connecting portion and a third connecting portion arranged in a triangle; The side-sway transmission mechanism comprises a first secondary connecting rod (121), a second secondary connecting rod (122) and a third secondary connecting rod (123); One end of the first connecting rod (111) is connected to the first connecting tool (41) via a joint bearing, the other end of the first connecting rod (111) is universally connected to the side swing connecting rod (110) via the second connecting rod (112), one end of the third connecting rod (113) is hinged to the side swing connecting rod (110), the other end of the third connecting rod (113) is hinged to the fourth connecting rod (114), and the fourth connecting rod (114) is hinged to the first connecting portion; The first auxiliary connecting rods (121) of the two sets of the side-swing transmission mechanisms are respectively movably connected to the second connecting fixture (42) and the third connecting fixture (43) via joint bearings; a pin rod (130) is provided between the first auxiliary connecting rods (121) on both sides; the first auxiliary connecting rod (121) and the second auxiliary connecting rod (122) are connected to the pin rod (130) via joint bearings; and the side-swing connecting rod (110) is hinged to the middle of the pin rod (130); The second secondary connecting rod (122) comprises a support rod (1221) and a coupling rod (1222), one end of the two support rods (1221) is hinged to the pin rod (130), and the first hinged portion and the second hinged portion are respectively hinged to the other ends of the two support rods (1221); the coupling rod (1222) comprises a first transmission connection portion and a second transmission connection portion, the first transmission connection portion is hinged to the third secondary connecting rod (123), the second transmission connection portion is hinged to the coupling connection portion, and the second connection portion and the third connection portion are respectively hinged to the two third secondary connecting rods (123); The first driver (21), the second driver (22) and the third driver (23) all comprise a housing (203), wherein a motor and the planetary roller screw pair are arranged in the housing (203); The planetary roller screw pair further comprises a retaining frame (204), wherein the retaining frame (204) is located between the nut (201) and the screw (202), and both ends of the roller (200) are respectively rotatably connected to the retaining frame (204); The motor comprises a stator (205) and a rotor (206), the stator (205) being arranged outside the rotor (206) and fixedly connected to the housing (203), and the lead screw (202) being fixedly connected to the rotor (206); A tension and pressure sensor is provided on one end of the housing (203) away from the nut (201); a rotary encoder is provided between the lead screw (202) and the housing (203); a linear displacement sensor is provided between the nut (201) and the inner wall of the housing (3); a control unit is provided in the housing (203); and the motor, the linear displacement sensor, the rotary encoder and the tension and pressure sensor are all electrically connected to the control unit.

2. A direct-drive finger structure according to claim 1, characterized in that: The angle formed by the first connecting fixture (41) and the horizontal end surface of the nut (201) is denoted as a1; the angle formed by the second connecting fixture (42) and the horizontal end surface of the nut (201) is equal to the angle formed by the third connecting fixture (43) and the horizontal end surface of the nut (201) and is denoted as a2; wherein the values ​​of a1 and a2 are 35°-45°.

3. A direct-drive finger structure according to claim 1, characterized in that: The second connecting rod (112) and the side swing connecting rod (110) are hingedly connected to form a first rotational pair R1, the third connecting rod (113) and the side swing connecting rod (110) are hingedly connected to form a second rotational pair R2, and the side swing connecting rod (110) and the pin rod (130) are hingedly connected to form a third rotational pair R3; Lines connecting the rotation centers of the first rotation pair R1, the second rotation pair R2 and the third rotation pair R3 form line segments d1, d2 and d3, and the line segments d1, d2 and d3 form an obtuse triangle; The angle formed by the line connecting the first rotation pair R1 and the second rotation pair R2 and the line connecting the second rotation pair R2 and the third rotation pair R3 is 110°-120°.

4. The direct-drive finger structure according to claim 1, characterized in that: The third connecting rod (113) and the fourth connecting rod (114) are hinged to form a fourth rotation pair R4, the fourth connecting rod (114) and the first connecting portion are hinged to form a fifth rotation pair R5, and the second transmission connecting portion and the coupling connecting portion are hinged to form a sixth rotation pair R6; Lines connecting the rotation centers of the fourth rotation pair R4, the fifth rotation pair R5 and the sixth rotation pair R6 form line segments d4, d5 and d6, and the line segments d4, d5 and d6 form an obtuse triangle; Among them, the angle formed by the line connecting the fourth rotation pair R4 and the fifth rotation pair R5 and the line connecting the fifth rotation pair R5 and the sixth rotation pair R6 is 10°-20°, the angle formed by the line connecting the fourth rotation pair R4 and the sixth rotation pair R6 and the line connecting the fifth rotation pair R5 and the sixth rotation pair R6 is 50°-55°, and the angle formed by the line connecting the fourth rotation pair R4 and the sixth rotation pair R6 and the line connecting the fourth rotation pair R4 and the fifth rotation pair R5 is 110°-120°.

5. The direct-drive finger structure according to claim 1, characterized in that: A center line connecting the first transmission connection part and the second transmission connection part on the coupling rod (1222) is perpendicular to the extension direction of the main body of the coupling rod (1222).

6. A direct-drive finger structure according to claim 1 or 5, characterized in that: The angle between the support rod (1221) and the coupling rod (1222) in the second secondary connecting rod (122) is 45°.

7. The direct-drive finger structure according to claim 1, characterized in that: An arc-shaped curved structure is provided at a position of the third secondary connecting rod (123) close to the first transmission connection portion, and the bending direction of the arc-shaped curved structure is consistent with the bending direction of the finger assembly (1).

8. The direct-drive finger structure according to claim 1, characterized in that: The rotary encoder comprises a reading unit (207) and a magnetic pole (208); a magnetic sleeve (209) is fixedly provided at one end of the lead screw (202); the magnetic pole (208) is fixedly provided on the magnetic sleeve (209); the magnetic pole (208) and the reading unit (207) are arranged opposite to each other; and the reading unit (207) is electrically connected to the control unit.

9. The direct-drive finger structure according to claim 1, characterized in that: A bearing (210) is provided between the lead screw (202) and the housing (203).

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