Multi-degree-of-freedom fruit and vegetable picking end effector

Abstract

The invention relates to the technical field of agricultural picking machinery, in particular to a multi-degree-of-freedom fruit and vegetable picking end effector which mainly comprises a mechanical gripper and a multi-degree-of-freedom joint, a rigid knuckle set, a pulling device, a winding device and an adsorption structure are designed on a soft finger of the mechanical gripper, and the clamping force and stability of the end effector are improved; the multi-degree-of-freedom joint can drive pitching action, swing angle action and rotation action at the same time, the degree of freedom of the end effector is increased, the end effector can adapt to fruits in different growth postures through the multi-degree-of-freedom joint, and the pose adjusting precision of the end effector is improved.

Description

Technical Field

[0001] This invention relates to the field of agricultural harvesting machinery technology, and in particular to a multi-degree-of-freedom fruit and vegetable harvesting end effector. Background Technology

[0002] Finger-based structures, known as fin-effect fingers, are a type of highly compliant biomimetic flexible gripper that has been widely used in object grasping and manipulation. However, existing agricultural harvesting robots typically use fin-shaped soft fingers directly to grasp and harvest fruit, a design that suffers from insufficient gripping stability during fruit picking. Summary of the Invention

[0003] Based on the above problems, the purpose of this invention is to provide a multi-degree-of-freedom fruit and vegetable harvesting end effector. The invention adopts the following technical solution:

[0004] This invention provides a multi-degree-of-freedom fruit and vegetable harvesting end effector, including a robotic gripper. The robotic gripper includes a robotic gripper base. A large suction cup is provided in the middle of the top surface of the robotic gripper base. Multiple soft finger connecting seats are arranged around the robotic gripper base. The soft finger connecting seats are movably connected to the robotic gripper base through a connecting seat rotation position.

[0005] Each of the aforementioned soft finger connectors is provided with a fin-shaped soft finger, and a small suction cup is provided on the clamping surface of the fin-shaped soft finger;

[0006] Each of the fin-shaped soft fingers is provided with a rigid phalanx group consisting of multiple phalanges connected together, and the rigid phalanx group is driven by a pulling device.

[0007] Preferably, the rigid knuckle group is provided on both sides of the fin-shaped soft finger, and the distal ends of the rigid knuckle group on both sides are connected by a distal knuckle rod, which abuts against the back of the fin-shaped soft finger.

[0008] The rigid phalanx assembly includes a rigid distal phalanx, a rigid middle phalanx, and a rigid proximal phalanx; the distal end of the rigid distal phalanx is connected to the distal end of the rigid distal phalanx on the other side via the distal phalanx rod; the adjacent ends of the rigid distal phalanx and the rigid middle phalanx are rotatably connected via a first rotational position, which is located on the fin-shaped soft finger; the adjacent ends of the rigid middle phalanx and the rigid proximal phalanx are rotatably connected via a second rotational position, which is located on the fin-shaped soft finger; the proximal end of the rigid proximal phalanx is rotatably connected to the connecting seat rotational position.

[0009] Preferably, the pulling device includes a first guide slide, a second guide slide, a third guide slide, a fourth guide slide, and a flexible rope.

[0010] The first guide slide is disposed at the first rotation position; the second guide slide is disposed at the second rotation position; the third guide slide is disposed at the connecting seat rotation position; the fourth guide slide is located below the third guide slide and is disposed on the robot arm base;

[0011] One end of the flexible rope is connected to the distal finger joint rod, and the other end starts from the inside of the first guide member, bends and passes through the first guide member, the second guide member, the third guide member, and the fourth guide member in sequence, and then connects to the winding device.

[0012] Preferably, the first guide slide, the second guide slide, the third guide slide and the fourth guide slide are all guide pulleys, and the outer peripheral surface of the guide pulley is provided with a V-shaped limiting groove.

[0013] Preferably, the winding device includes a winding motor located below the robot arm base, the winding motor being mounted on the base plate, and the base plate being connected to the robot arm base;

[0014] The winding motor has a winding spindle on its drive shaft, and each of the flexible ropes is wound on the winding spindle.

[0015] Preferably, the large suction cup is mounted on an elastic buffer device, which includes a suction cup mounting base. An airbag is located at the center of the bottom of the suction cup mounting base. Multiple guide rods are arranged around the suction cup mounting base. The guide rods are slidably connected to the robot arm base, and a return spring is sleeved on the guide rod.

[0016] Preferably, a tension spring is provided at the lower part of the soft finger connector, one end of the tension spring is connected to the soft finger connector, and the other end is connected to the robot arm base.

[0017] Preferably, the robotic gripper is mounted on a multi-degree-of-freedom joint.

[0018] Preferably, the multi-degree-of-freedom joint includes a front end cap and a rear end cap, and a universal joint is provided between the front end cap and the rear end cap. One end of the universal joint is connected and fixed to the front end cap, and the other end is connected to the shaft of a rotary drive motor. The rotary drive motor is fixed on the rear end cap.

[0019] Two telescopic drive components are provided on one side of the universal joint, and two spring damping components are provided on the other side. The rear ends of the telescopic drive components and spring damping components are fixed to the rear end cover of the joint. The front ends of the telescopic drive components and spring damping components are provided with ball bearings, which roll in contact with the bottom surface of the front end cover of the joint.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0021] I. This invention, through the design of a rigid finger joint assembly, a pulling device, and a winding device, causes the entire soft finger to begin to retract inward. Subsequently, the soft finger deforms due to the pressure against the fruit surface. When the pulling force is further increased, the middle part of the soft finger also undergoes an inward bending deformation. When the pulling force reaches its maximum, the distal finger joint retracts inward, and the pressure bar of the distal finger joint begins to press down on the distal end of the soft finger. In this way, the surface of the soft finger completely adheres to the surface of the fruit, maximizing the coverage of the soft finger.

[0022] II. This invention utilizes an airbag suction cup installed at the center of the robotic arm base. After the fruit is stably held by the soft finger, the airbag is filled with gas, rapidly increasing its volume and lifting the suction cup fixing structure. Under the constraint of the guide holes in the robotic arm base, the suction cup fixing structure begins to move linearly towards the fruit until the suction cup is completely pressed against the fruit surface. At this point, a negative pressure is formed inside the suction cup, gripping the fruit surface. This further ensures a tighter fit between the fruit and the suction cup on the soft finger. The suction force of the suction cup also provides a greater gripping force on the fruit, which is beneficial for stable harvesting and improves the harvesting success rate.

[0023] Third, the multi-degree-of-freedom joints designed in this invention can be connected to robotic arms and manipulators at short distances, enabling the manipulator to perform pitching, swinging, and rotating movements under the operation of the multi-degree-of-freedom joints. All three degrees of freedom movements can be performed simultaneously without interference. The overall structure is compact and lightweight, achieving multiple movements in a small space. It adapts to the natural growth posture of the fruit, saves space for the robotic arm's movements, and reduces the energy consumption of the robotic arm. It is particularly suitable for precision harvesting operations in densely planted environments. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] Figure 1 This is a schematic diagram of the robotic gripper part in the multi-degree-of-freedom fruit and vegetable harvesting end effector of the present invention;

[0026] Figure 2 This is a schematic diagram of the rigid finger joint assembly of the robotic gripper part of the present invention;

[0027] Figure 3 This is a schematic diagram of the pulling device of the robotic gripper part of the present invention;

[0028] Figure 4 This is a schematic diagram of the winding device for the robotic gripper part of the present invention;

[0029] Figure 5 This is a schematic diagram of the gear engagement in the winding device of the present invention;

[0030] Figure 6This is a schematic diagram of the elastic buffer device of the present invention;

[0031] Figure 7 This is a schematic diagram of the assembly of the robotic gripper and multi-degree-of-freedom joints in the multi-degree-of-freedom fruit and vegetable harvesting end effector of the present invention.

[0032] Figure 8 This is a schematic diagram of the multi-degree-of-freedom joint in the multi-degree-of-freedom fruit and vegetable harvesting end effector of the present invention;

[0033] Figure 9 This is a schematic diagram of the specific structure of the telescopic drive component and the spring damping component of the present invention.

[0034] Explanation of reference numerals in the attached drawings: 1. Robotic arm base; 2. Large suction cup; 3. Soft finger connector; 4. Connecting seat rotation position; 5. Fin-shaped soft finger; 6. Small suction cup; 7. Rigid finger joint assembly; 701. Rigid distal finger joint; 702. Rigid middle finger joint; 703. Rigid proximal finger joint; 704. First rotation position; 705. Second rotation position; 8. Pulling device; 801. First guide slide; 802. Second guide slide; 803. Third guide slide; 804. Fourth guide slide; 805. Flexible rope; 9. Distal finger joint rod; 10. Winding device; 1001. Winding motor; 1002. Base plate; 10 03. Winding spindle; 11. Elastic buffer device; 1101. Suction cup fixing seat; 1102. Return spring; 1103. Airbag; 1104. Guide rod; 12. Tension spring; 13. Joint front end cover; 14. Joint rear end cover; 15. Universal joint; 16. Telescopic drive component; 1601. Joint drive motor; 1602. Lead screw; 1603. Flange seat; 1604. Guide rod; 1604; 1605. Guide sleeve; 17. Spring damping component; 1701. Damping rod; 1702. Damping rod shaft head; 1703. Damping spring; 18. Rotary drive motor; 19. Ball bearing. Detailed Implementation

[0035] To make the technical problems, technical solutions, and beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0036] like Figure 1As shown, this embodiment discloses a multi-degree-of-freedom fruit and vegetable harvesting end effector, including a robotic gripper. The robotic gripper includes a robotic base 1, with a large suction cup 2 located in the center of the top surface of the robotic base 1. Multiple connecting seat rotation positions 4 are arranged around the robotic base 1, and a soft finger connecting seat 3 is installed on each connecting seat rotation position 4. The soft finger connecting seat 3 is movably connected to the robotic base 1 through the connecting seat rotation position 4. Each soft finger connecting seat 3 is either converging towards or moving away from the center of the robotic base 1 around the connecting seat rotation position 4. The connecting seat rotation position 4 is composed of holes provided on the soft finger connecting seat 3 and holes provided on the robotic base 1. The soft finger connecting seat 3 and the holes on the robotic base 1 are connected by a pin, so that the soft finger connecting seat 3 is rotatably connected to the robotic base 1.

[0037] Each soft finger connector 3 is equipped with a fin-shaped soft finger 5. The fin-shaped soft finger 5 is a type of bionic flexible gripper with extremely strong flexibility, based on the fin effect structure. It has been widely used in the field of object grasping and manipulation. Three small suction cups 6 are provided on the gripping surface of the fin-shaped soft finger 5. The three small suction cups 6 are respectively arranged in the far, middle and near positions of the fin-shaped soft finger 5.

[0038] Each fin-shaped soft finger 5 is provided with a rigid finger joint group 7 consisting of multiple finger joints connected together. The rigid finger joint group 7 is driven by a pulling device 8. The pulling device 8 drives the rigid finger joint group 7 to move, thereby driving the fin-shaped soft finger 5 to grasp or release.

[0039] In this embodiment, rigid knuckle groups 7 are provided on both sides of the fin-shaped soft finger 5. The distal ends of the rigid knuckle groups 7 on both sides are connected by distal knuckle rods 9, and the distal knuckle rods 9 abut against the back of the fin-shaped soft finger 5.

[0040] like Figure 2 As shown, the rigid phalanx group 7 includes a rigid distal phalanx 701, a rigid middle phalanx 702, and a rigid proximal phalanx 703. The distal end of the rigid distal phalanx 701 is connected to the distal end of the other rigid distal phalanx 701 via a distal phalanx rod 9. The adjacent ends of the rigid distal phalanx 701 and the rigid middle phalanx 702 are rotatably connected via a first rotating position 704, which is mounted on the fin-shaped soft finger 5. The adjacent ends of the rigid middle phalanx 702 and the rigid proximal phalanx 703 are rotatably connected via a second rotating position 705, which is mounted on the fin-shaped soft finger 5. The proximal end of the rigid proximal phalanx 703 is rotatably connected to a connecting seat rotating position 4.

[0041] In this embodiment, the first rotation position 704 and the second rotation position 705 are both rotating shafts, which are fixed to the side of the fin-shaped soft finger 5, and the finger joint is rotatably connected to the corresponding rotating shaft.

[0042] Based on the structure of the rigid finger group 7 described above, such as Figure 3 As shown, the pulling device 8 includes a first guide slide 801, a second guide slide 802, a third guide slide 803, a fourth guide slide 804, and a flexible rope 805. The first guide slide 801 is rotatably mounted on a first rotating position 704; the second guide slide 802 is rotatably mounted on a second rotating position 705; the third guide slide 803 is rotatably mounted on a connecting seat rotating position 4; the fourth guide slide 804 is located below the third guide slide 803 and rotates on the robot arm base 1.

[0043] One end of the flexible rope 805 is connected to the distal finger joint rod 9, and the other end starts from the inside of the first guide slide 801, bends and passes around the first guide slide 801, the second guide slide 802, the third guide slide 803 and the fourth guide slide 804 in sequence, and then connects to the winding device 10.

[0044] The flexible rope component 805 can be made of steel wire rope. The first guide slide 801, the second guide slide 802, the third guide slide 803, and the fourth guide slide 804 are all guide pulleys, and V-shaped limiting grooves are provided on the outer circumferential surface of the guide pulleys. The flexible rope component 805 is located in the V-shaped limiting grooves.

[0045] The working principle of the robotic gripper of this invention is as follows:

[0046] The winding device 10 winds and tightens the flexible rope 805. The flexible rope 805 is then taut. Afterwards, due to the large pressure angle of the third guide member 803, the torque at the hinge point is greater than the torque at the rigid distal phalanx 701 and the rigid middle phalanx 702. Therefore, the rigid proximal phalanx 703 first drives the entire phalanx to retract inwards. Then, because the pressure angles of the rigid middle phalanx 702 and the rigid distal phalanx 701 are similar, the torques of the rigid middle phalanx 702 and the rigid distal phalanx 701 are not much different. After the proximal end of the fin-shaped soft finger 5 contacts the fruit surface, the resistance torque at the finger root hinge point cancels out the torque at the hinge point. When the resultant torque is greater than the torques of other phalanxes, the rigid middle phalanx 702 and the rigid proximal phalanx 703 begin to move. The rigid middle phalanx 702, because it winds from the outside of the finger, will rotate outwards, spreading the outer surface of the soft finger outwards. The rigid distal phalanx 701, because it winds from the inside, will rotate inwards, squeezing the distal part of the soft finger inwards. This achieves three-directional force deformation of the fin-shaped soft finger 5 under normal compression. Therefore, rotation begins first, with the proximal phalanx driving the entire fin-shaped soft finger 5 to rotate, and the fin-shaped soft finger 5 begins to contact the fruit and generate pressure. When the compression force at the base of the soft finger is greater, the other two fingers begin to move. The pressure angles of the rigid middle phalanx 702 and the rigid distal phalanx 701 are approximately the same, and the torque difference is not significant. The rigid middle phalanx 702 spreads the outer side of the middle part of the soft finger outwards, while the rigid distal phalanx 701 compresses the distal end of the soft finger. This rigid phalanx drive allows the soft finger to deform under single internal pressure, increasing the coverage area of ​​the soft finger without easily damaging its soft structure.

[0047] After the soft finger grips the fruit, the small suction cup 6 on the inside of the soft finger adheres to the surface of the fruit. Under the action of the elastic buffer device 11, the large suction cup 2 begins to lift up, and a negative pressure is formed inside the large suction cup 2, which firmly adheres to the surface of the fruit. Lifting up and squeezing the fruit makes it fit more tightly with the small suction cup 6 of the fin-shaped soft finger 5. The adsorption force of the large and small suction cups makes the picking pull greater.

[0048] like Figure 4 and 5 As shown, in this embodiment, the winding device 10 includes a winding motor 1001, which is located below the robot base 1. The winding motor 1001 is mounted and fixed on the base plate 1002, which is connected to the robot base 1. A winding spindle 1003 is mounted on the drive shaft of the winding motor 1001, and each flexible rope 805 is wound on the winding spindle 1003. The winding spindle 1003 is rotatably connected to the robot base 1.

[0049] like Figure 6 As shown, the large suction cup 2 is mounted on the elastic buffer device 11, which is fixed to the bottom of the robot base 1. The elastic buffer device 11 includes a suction cup fixing seat 1101, on which the large suction cup 2 is fixed. An airbag 1103 is located in the middle of the bottom of the suction cup fixing seat 1101. The airbag 1103 is connected to an inflation / deflation device. Both ends of the airbag 1103 are fixed to the suction cup fixing seat 1101 and the robot base 1, respectively. Multiple guide rods 1104 are arranged around the suction cup fixing seat 1101. One end of the guide rod 1104 is fixed to the suction cup fixing seat 1101, and the other end of the guide rod 1104 is slidably connected to the reserved guide hole on the robot base 1. Each guide rod 1104 is fitted with a return spring 1102. Both ends of the return spring 1102 are in contact with the robot base 1 and the suction cup fixing seat 1101, respectively.

[0050] like Figure 3 As shown, a tension spring 12 is provided at the lower part of the soft finger connecting seat 3. One end of the tension spring 12 is connected to the soft finger connecting seat 3, and the other end is connected to the robot arm base 1. When the winding device 10 releases the flexible rope 805, the flexible rope 805 stretches. Under the action of the tension spring 12, the fin-shaped soft finger 5 first begins to return to its original position and extend. Then, due to its own elasticity, the fin-shaped soft finger 5 also begins to extend to its initial state. Each fruit detaches from the suction cup, and the rigid finger joint also returns to its initial state, releasing the fruit and placing it into the fruit frame.

[0051] like Figures 7 to 9As shown, the robotic gripper is mounted on a multi-degree-of-freedom joint. The multi-degree-of-freedom joint includes a front joint cover 13 and a rear joint cover 14. The top surface of the front joint cover 13 is fixed to the base plate 1002. A universal joint 15 is provided between the front joint cover 13 and the rear joint cover 14. One end of the universal joint 15 is connected and fixed to the front joint cover 13, and the other end is connected to the shaft of a rotary drive motor 18. The rotary drive motor 18 is fixed to the rear joint cover 14.

[0052] Two telescopic drive members 16 are provided on one side of the universal joint 15, and two spring damping members 17 are provided on the other side. The telescopic drive members 16 and the spring damping members 17 on the opposite side are arranged correspondingly to each other. The rear ends of the telescopic drive members 16 and the spring damping members 17 are fixed to the rear end cover 14 of the joint. The front ends of the telescopic drive members 16 and the spring damping members 17 are provided with ball bearings 19. The ball bearings 19 are in a rolling contact with the bottom surface of the front end cover 13 of the joint.

[0053] The working principle of a multi-degree-of-freedom joint is as follows:

[0054] When the fruit is tilted upwards or downwards at a single angle, the telescopic drive 16 will advance or retract. The spring damper 17 aligned by the telescopic drive 16 will be popped out or pressed back, thereby causing the joint front cover 13 to rise or fall in one direction, making a picking tilting motion. At the same time, the rotary drive motor 18 drives the joint front cover 13 and the robotic gripper to rotate together through the universal joint 15.

[0055] Specifically, the telescopic drive component 16 includes a joint drive motor 1601, a lead screw 1602 is mounted on the output shaft of the joint drive motor 1601, the upper end of the lead screw 1602 is threadedly connected to the flange seat 1603, a ball bearing 19 is mounted on the top of the flange seat 1603, a guide rod 1604 is provided on one side of the flange seat 1603, the upper end of the guide rod 1604 is fixedly connected to the flange seat 1603, and the lower end is slidably connected to the guide sleeve 1605, which is fixed on the rear end cover 14 of the joint.

[0056] The spring damping component 17 includes a damping rod 1701 with telescopic function. A damping rod shaft head 1702 is fixed to the front end of the damping rod 1701. A ball bearing 19 is installed on the top of the damping rod shaft head 1702. A damping spring 1703 is sleeved on the damping rod 1701. The two ends of the damping spring 1703 abut against the damping rod shaft head 1702 and the base of the damping rod 1701, respectively.

[0057] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A multi-degree-of-freedom fruit and vegetable harvesting end effector, characterized in that, The device includes a robotic gripper, which includes a robotic gripper base (1). A large suction cup (2) is provided in the middle of the top surface of the robotic gripper base (1). Multiple soft finger connecting seats (3) are arranged around the robotic gripper base (1). The soft finger connecting seats (3) are movably connected to the robotic gripper base (1) through a connecting seat rotation position (4). Each of the soft finger connectors (3) is provided with a fin-shaped soft finger (5), and a small suction cup (6) is provided on the clamping surface of the fin-shaped soft finger (5). Each of the fin-shaped soft fingers (5) is provided with a rigid phalanx group (7) consisting of multiple phalanges connected together, the rigid phalanx group (7) being driven by a pulling device (8).

2. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 1, characterized in that: The rigid knuckle group (7) is provided on both sides of the fin-shaped soft finger (5). The distal ends of the rigid knuckle group (7) on both sides are connected by a distal knuckle rod (9). The distal knuckle rod (9) abuts against the back of the fin-shaped soft finger (5). The rigid phalanx assembly (7) includes a rigid distal phalanx (701), a rigid middle phalanx (702), and a rigid proximal phalanx (703). The distal end of the rigid distal phalanx (701) is connected to the distal end of the rigid distal phalanx (701) on the other side via the distal phalanx rod (9). The adjacent ends of the rigid distal phalanx (701) and the rigid middle phalanx (702) are rotatably connected via a first rotation position (704), which is located on the fin-shaped soft finger (5). The adjacent ends of the rigid middle phalanx (702) and the rigid proximal phalanx (703) are rotatably connected via a second rotation position (705), which is located on the fin-shaped soft finger (5). The proximal end of the rigid proximal phalanx (703) is rotatably connected to the connecting seat rotation position (4).

3. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 2, characterized in that: The pulling device (8) includes a first guide (801), a second guide (802), a third guide (803), a fourth guide (804), and a flexible rope (805). The first guide slide (801) is disposed on the first rotating position (704); the second guide slide (802) is disposed on the second rotating position (705); the third guide slide (803) is disposed on the connecting seat rotating position (4); the fourth guide slide (804) is located below the third guide slide (803) and is disposed on the robot arm base (1); One end of the flexible rope (805) is connected to the distal finger joint rod (9), and the other end starts from the inside of the first guide (801), bends and passes around the first guide (801), the second guide (802), the third guide (803), and the fourth guide (804) in sequence before being connected to the winding device (10).

4. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 3, characterized in that: The first guide slide (801), the second guide slide (802), the third guide slide (803) and the fourth guide slide (804) are all guide pulleys, and a V-shaped limiting groove is provided on the outer circumferential surface of the guide pulley.

5. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 3, characterized in that: The winding device (10) includes a winding motor (1001), which is located below the robot base (1). The winding motor (1001) is mounted on the base plate (1002), which is connected to the robot base (1). The winding motor (1001) has a winding spindle (1003) on its drive shaft, and each of the flexible ropes (805) is wound on the winding spindle (1003).

6. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 1, characterized in that: The large suction cup (2) is mounted on the elastic buffer device (11); the elastic buffer device (11) includes a suction cup fixing seat (1101), an airbag (1103) is provided at the middle position of the bottom of the suction cup fixing seat (1101), and a plurality of guide rods (1104) are arranged around the suction cup fixing seat (1101). The guide rods (1104) are slidably connected to the robot arm base (1), and a return spring (1102) is sleeved on the guide rods (1104).

7. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 1, characterized in that: A tension spring (12) is provided at the lower part of the soft finger connector (3). One end of the tension spring (12) is connected to the soft finger connector (3), and the other end is connected to the robot arm base (1).

8. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 1, characterized in that: The robotic gripper is mounted on a multi-degree-of-freedom joint.

9. The multi-degree-of-freedom fruit and vegetable harvesting end effector according to claim 8, characterized in that: The multi-degree-of-freedom joint includes a front end cap (13) and a rear end cap (14). A universal joint (15) is provided between the front end cap (13) and the rear end cap (14). One end of the universal joint (15) is connected and fixed to the front end cap (13), and the other end is connected to the shaft of a rotary drive motor (18). The rotary drive motor (18) is fixed on the rear end cap (14). Two telescopic drive members (16) are provided on one side of the universal joint (15), and two spring damping members (17) are provided on the other side. The rear ends of the telescopic drive members (16) and the spring damping members (17) are fixed to the rear end cover (14) of the joint. The front ends of the telescopic drive members (16) and the spring damping members (17) are provided with ball bearings (19). The ball bearings (19) are in rolling contact with the bottom surface of the front end cover (13) of the joint.

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