Differential picking end effector integrating shearing and clipping

Abstract

The application relates to the technical field of mechanical hands and discloses a differential-speed picking end effector integrating clamping and shearing, which comprises a guide structure, a driving structure, a differential mechanism, a transmission structure, a cutter assembly and a clamping assembly. The driving structure is installed on the side of the guide structure, the driving structure is connected with the transmission structure through the differential mechanism, the differential mechanism is installed on the guide structure through a differential mechanism fixing base, the cutter assembly is movably installed on one guide structure through one transmission structure, the clamping assembly is movably installed on another guide structure through another transmission structure, and the two guide structures are connected. The application can make two clamping claws or cutters move at different speeds, when one side cannot move when contacting fruits or fruit stems, the other side can normally work, picking can be completed, different shapes and postures of targets can be adapted, the positioning precision of the fruits is low, and the application has wide generality.

Description

Technical Field

[0001] This invention relates to the technical field of robotic arms, and more particularly to a differential-speed picking end effector that integrates clamping and shearing. Background Technology

[0002] Most current end effectors for fruit harvesting, such as gripping and shearing mechanisms or common grippers, are based on symmetrical structural designs, like scissors and pneumatic fingers. This is especially true in fruit harvesting, where the design assumes the fruit has an ideal symmetrical shape. However, during fruit growth, environmental factors cause the fruit to deviate from its symmetrical shape, and the fruit stalk often forms an angle with the fruit's central axis. When a symmetrical gripper or shearing mechanism encounters resistance on one side, the symmetry prevents the other side from moving, leading to jamming and harvesting failure.

[0003] Furthermore, when grippers or cutters based on symmetrical structures are working, especially when picking fruit from trees, they need to be aligned with the target's axis of symmetry, which requires high positioning accuracy. However, current vision systems are easily affected by the environment, and in real-world environments, positioning accuracy is difficult to guarantee. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a differential picking end effector that integrates clamping and shearing.

[0005] The objective of this invention is achieved through the following technical solution: A differential harvesting end effector integrating clamping and shearing includes a guide structure, a drive structure, a differential, a transmission structure, a cutting assembly, and a clamping assembly. The drive structure is installed on the side of the guide structure and is connected to the transmission structure via the differential. The differential is installed on the guide structure via a differential mounting base. The cutting assembly is movably installed on one of the guide structures via one of the transmission structures, and the clamping assembly is movably installed on another guide structure via another transmission structure. The two guide structures are connected in parallel.

[0006] A preferred embodiment includes a guide structure comprising a first lead screw fixing seat, a base plate, a second lead screw fixing seat, a first guide rod, and a second guide rod. The first and second lead screw fixing seats are both mounted on both ends of the base plate. One end of the first guide rod and one end of the second guide rod are both mounted on the first lead screw fixing seat, and the other end of the first guide rod and the other end of the second guide rod are both mounted on the second lead screw fixing seat. The transmission structure is slidably connected to the first and second guide rods respectively. Both ends of the transmission structure are rotatably mounted on the first and second lead screw fixing seats. The drive structure is connected to the base plate, and the differential fixing seat is mounted on the first lead screw fixing seat.

[0007] A preferred option is that the drive structure includes a drive motor, a motor bracket, and an input shaft bevel gear. The drive motor is mounted on the guide structure via the motor bracket, and the drive motor is connected to the differential via the input shaft bevel gear.

[0008] A preferred embodiment of the differential includes a second output bevel gear, a revolution bevel gear, an input bevel gear, a differential housing, a first output bevel gear, a half-shaft bevel gear, and planetary gears. The second output bevel gear is connected to the revolution bevel gear via a rotating shaft. The revolution bevel gear is connected to the differential housing. The input bevel gear is located at the center of the revolution bevel gear. The planetary gears are rotatably mounted inside the differential housing. The input bevel gear is connected to the half-shaft bevel gear via the planetary gears. The half-shaft bevel gear is connected to the first output bevel gear via a rotating shaft. Both the first and second output bevel gears are connected to the transmission structure. The rotating shaft is rotatably mounted on the differential mounting bracket.

[0009] A preferred embodiment includes a transmission structure comprising a first bevel gear, a first lead screw, a second bevel gear, a second lead screw, a first lead screw slider, a second lead screw slider, and a laser rangefinder sensor. Both the first and second lead screws are rotatably mounted on the guide structure. The first lead screw is connected to one end of the differential via the first bevel gear, and the second lead screw is connected to the other end of the differential via the second bevel gear. The first lead screw slider is threaded to the first lead screw, and the second lead screw slider is threaded to the second lead screw. Both the first and second lead screw sliders are slidably mounted on the guide structure. The laser rangefinder sensor is mounted at both ends of the guide structure. Both the first and second lead screw sliders correspond to the laser rangefinder sensor. One first lead screw slider and one second lead screw slider are connected to the cutting assembly, and the other first lead screw slider and the other second lead screw slider are connected to the clamping assembly.

[0010] A better option is that the cutting assembly includes a first cutting blade and a second cutting blade, both of which are mounted on a transmission structure and are matched.

[0011] In a preferred embodiment, the clamping assembly includes a first jaw, a second jaw, and a pressure sensor. The first jaw and the second jaw are both mounted on another of the aforementioned transmission structures. The pressure sensor is mounted on the second jaw and is located between the first jaw and the second jaw. The first jaw and the second jaw are matched.

[0012] A better option also includes a robotic arm mounting bracket, which is connected to a guide structure.

[0013] The present invention has the following advantages and beneficial effects compared with the prior art:

[0014] This invention, through its guiding structure, driving structure, differential, transmission structure, cutting assembly, and clamping assembly, enables two grippers or cutting blades to move at different speeds. When one side is unable to move due to contact with the fruit or stem, the other side can still work normally to complete the harvesting. It can adapt to targets of different shapes and postures, has low requirements for fruit positioning accuracy, and is widely applicable. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a differential harvesting end effector integrating clamping and shearing according to the present invention;

[0016] Figure 2 This is a schematic diagram of a differential harvesting end effector integrating clamping and shearing according to the present invention;

[0017] Figure 3 This is a schematic diagram of the shearing mechanism of a differential picking end effector integrating clamping and shearing according to the present invention;

[0018] Figure 4 This is a schematic diagram of the clamping mechanism of a differential picking end effector integrating clamping and shearing according to the present invention;

[0019] Figure 5 This is a schematic diagram of the differential of a differential picking end effector integrating clamping and shearing according to the present invention;

[0020] Figure 6 This is a schematic diagram of the differential inside a differential harvesting end effector that integrates clamping and shearing according to the present invention;

[0021] Figure 7 This is a schematic diagram of the differential inside a differential harvesting end effector that integrates clamping and shearing according to the present invention;

[0022] The components in the attached diagram are labeled as follows: 1-Guide structure; 11-First lead screw fixing seat; 12-Base plate; 13-Second lead screw fixing seat; 14-First guide rod; 15-Second guide rod; 2-Drive structure; 21-Drive motor; 22-Motor bracket; 23-Input shaft bevel gear; 3-Transmission structure; 31-First bevel gear; 32-First lead screw; 33-Second bevel gear; 34-Second lead screw; 35-First lead screw slider; 36-Second lead screw slider; 37-Laser rangefinder sensor; 4-Cutter assembly; 41-First cutter; 42-Second cutter; 5-Clamping assembly; 51-First gripper; 52-Second gripper; 53-Pressure sensor; 6-Differential gear; 61-First output bevel gear; 62-Revolutionary bevel gear; 63-Differential housing; 64-Second output bevel gear; 65-Half-shaft bevel gear; 66-Planetary gear; 67-Input bevel gear; 68-Differential mounting base; 7-Robot arm mounting bracket. Detailed Implementation

[0023] The invention's objective will be further described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail here, but the implementation of the invention is not limited to the following embodiments.

[0024] like Figure 1-2 As shown, a differential harvesting end effector integrating clamping and shearing includes a shearing mechanism, a clamping mechanism, and a robotic arm mounting bracket 7. The shearing mechanism includes a guide structure 1, a drive structure 2, a differential 6, a transmission structure 3, and a cutting assembly 4. The clamping mechanism includes a guide structure 1, a drive structure 2, a differential 6, a transmission structure 3, and a clamping assembly 5. The two guide structures 1 are bolted together vertically, and the robotic arm mounting bracket 7 is installed at the bottom of the two guide structures 1. The two drive structures 2 are respectively fixed to the rear side of the two guide structures 1, and the two differentials 6 are respectively installed on the left side of the two guide structures 1 through differential retainers 68. The two transmission structures 3 are rotatably mounted on the two guide structures 1, with one end of each transmission structure 3 protruding from the side of the two guide structures 1. The two drive structures 2 are respectively connected to the middle of the two differentials 6. The two ends of the upper differential 6 are connected to one end of the upper transmission structure 3, and the two ends of the lower differential 6 are connected to one end of the lower transmission structure 3. A cutting assembly 4 is mounted on the upper transmission structure 3, and the cutting assembly 4 can move left and right relative to the upper guide structure 1. A clamping assembly 5 is mounted on the lower transmission structure 3, and the clamping assembly 5 can move left and right relative to the lower guide structure 1. The cutting assembly 4 is located above the clamping assembly 5.

[0025] The shearing mechanism is used to cut the fruit stems. The clamping mechanism is used to clamp the fruit to prevent it from falling due to gravity after cutting. The robotic arm mounting bracket 7 is used to fix the differential harvesting end effector on the robotic arm. The guide structure 1 is used to guide the left and right movement of the cutting assembly 4 and the clamping assembly 5. The drive structure 2 is used to provide power for the movement speed of the cutting assembly 4 and the clamping assembly 5. The transmission structure 3 can obtain a large thrust with a small input torque and is self-locking, which is beneficial for the control of movement and clamping force. The cutting assembly 4 is used to cut the fruit stems. The clamping assembly 5 is used to clamp the fruit. The differential 6 makes the movement direction of the first lead screw 32 and the second lead screw 34 opposite, thereby making the movement direction of the first lead screw slider 35 and the second lead screw slider 36 opposite and moving at different speeds to realize the clamping or shearing action. The differential mounting bracket 68 is used to fix the differential 6.

[0026] like Figure 3-4 As shown, each guide structure 1 includes a first lead screw fixing seat 11, a base plate 12, a second lead screw fixing seat 13, a first guide rod 14, and a second guide rod 15. The first lead screw fixing seat 11 is perpendicularly connected to the left end of the base plate 12, and the second lead screw fixing seat 13 is perpendicularly connected to the right end of the base plate 12. The motor bracket 22 and the robotic arm fixing bracket 7 of the drive structure 2 are both mounted on the outer side of the base plate 12. The first lead screw fixing seat 11 and the second lead screw fixing seat 13 are each provided with two guide holes and two screw holes, with the two screw holes located on the outer side of the two guide holes. The first guide rod 14 and the second guide rod 15 are respectively mounted on the four guide holes.

[0027] The first lead screw fixing seat 11 and the second lead screw fixing seat 13 are used to fix the first guide rod 14 and the second guide rod 15. The outer side of the first lead screw fixing seat 11 is used to fix the motor bracket 22 and the differential fixing seat 68. The base plate 12 serves as a connecting support. The first guide rod 14 and the second guide rod 15 guide the first lead screw slider 35 and the second lead screw slider 36.

[0028] like Figure 3-4 As shown, each drive structure 2 includes a drive motor 21, a motor bracket 22, and an input shaft bevel gear 23. The motor bracket 22 is mounted on the outer side of the base plate 12 of the guide structure 1. The drive motor 21 is mounted on the motor bracket 22. The input shaft bevel gear 23 is mounted on the shaft of the drive motor 21 and is connected to the middle of the differential 6.

[0029] The drive motor 21 provides power for the movement of the cutting assembly 4 and the clamping assembly 5. The motor bracket 22 is used to fix the drive motor 21 in place. The input shaft bevel gear 23 serves to change the direction of rotation.

[0030] like Figure 5-7As shown, each differential 6 includes a first output bevel gear 61, a planetary bevel gear 62, a differential housing 63, a second output bevel gear 64, a half-shaft bevel gear 65, two planetary gears 66, and an input bevel gear 67. The second output bevel gear 64 is connected to the back of the planetary bevel gear 62 via a rotating shaft. The input bevel gear 67 is connected to the front of the planetary bevel gear 62 and is located at the center of the planetary bevel gear 62. The input bevel gear 67 is connected to the half-shaft bevel gear 65 via the two planetary gears 66. The differential housing 63 is connected to the planetary bevel gear 62, and the two planetary gears 66 are rotatably mounted inside the differential housing 63. The differential housing 63 covers the outer periphery of the input bevel gear 67, the planetary gears 66, and the half-shaft bevel gear 65. The half-shaft bevel gear 65 is connected to the first output bevel gear 61 via a rotating shaft. The first output bevel gear 61 is connected to the first bevel gear 31 of the transmission structure 3, and the second output bevel gear 64 is connected to the second bevel gear 33 of the transmission structure 3. The shaft is rotatably mounted on the differential mounting bracket 68.

[0031] The second output bevel gear 64 and the revolution bevel gear 62 achieve speed change and drive the second bevel gear 33 to rotate. The revolution bevel gear 62 serves as a steering transmission. The differential housing 63 is used to install and protect the planetary gear 66 and the half-shaft bevel gear 65, and to allow the planetary gear 66 to revolve. The first output bevel gear 61 is used for steering and transmission, transferring power to the first bevel gear 31. The half-shaft bevel gear 65 and the planetary gear 66 cooperate to change the moving speed of the two ends of the cutter assembly 4 or the two ends of the clamping assembly 5.

[0032] like Figure 3-4As shown, each transmission structure 3 includes a first bevel gear 31, a first lead screw 32, a second bevel gear 33, a second lead screw 34, a first lead screw slider 35, a second lead screw slider 36, and two laser rangefinders 37. One end of the first lead screw 32 and one end of the second lead screw 34 are rotatably mounted on the second lead screw fixing seat 13 of the guide structure 1. The other ends of the first lead screw 32 and the second lead screw 34 are rotatably mounted on the first lead screw fixing seat 11 of the guide structure 1 and pass through the first lead screw fixing seat 11 of the guide structure 1. The other end of the first lead screw 32 is connected to the first bevel gear 31, and the other end of the second lead screw 34 is connected to the second bevel gear 33. The first bevel gear 31 is connected to the first output bevel gear 61 of the differential 6, and the second bevel gear 33 is connected to the second output bevel gear 64 of the differential 6. The first lead screw slider 35 and the second lead screw slider 36 are slidably mounted on the first guide rod 14 and the second guide rod 15 of the guide structure 1. The first lead screw slider 35 is connected to the first lead screw 32 by a thread. The second lead screw slider 36 is connected to the second lead screw 34 via a thread and is located to the left of the first lead screw slider 35. The first cutter 41 of the cutter assembly 4 is bolted to the second lead screw slider 36 of the shearing mechanism, and the second cutter 42 of the cutter assembly 4 is bolted to the first lead screw slider 35 of the shearing mechanism. The first gripper 51 of the clamping assembly 5 is mounted on the second lead screw slider 36 of the clamping mechanism, and the second gripper 52 of the clamping assembly 5 is mounted on the first lead screw slider 35 of the clamping mechanism. Two laser rangefinders 37 are respectively mounted inside the first lead screw fixing seat 11 and the second lead screw fixing seat 13 of the guide structure 1. The laser rangefinder 37 on the left corresponds to the second lead screw slider 36, and the laser rangefinder 37 on the right corresponds to the first lead screw slider 35.

[0033] The first bevel gear 31 changes the direction of rotation and drives the first lead screw 32 to rotate. The first lead screw 32 and the first lead screw slider 35 are threaded together, allowing the rotation of the first lead screw 32 to move the first lead screw slider 35 left and right. The second bevel gear 33 changes the transmission direction and drives the second lead screw 34 to rotate. The cooperation between the second lead screw 34 and the second lead screw slider 36 allows the rotation of the second lead screw 34 to move the second lead screw slider 36 left and right. The laser range sensor 37 detects the movement distance of the first lead screw slider 35 and the second lead screw slider 36 respectively.

[0034] like Figure 3-4 As shown, the cutting assembly 4 includes a first cutting blade 41 and a second cutting blade 42. The first cutting blade 41 is mounted on the first lead screw slider 35 of the transmission structure 3 of the cutting mechanism, and the second cutting blade 42 is mounted on the second lead screw slider 36 of the transmission structure 3 of the cutting mechanism. The first cutting blade 41 and the second cutting blade 42 correspond to each other to cut the fruit stem.

[0035] like Figure 3-4 As shown, the clamping assembly 5 includes a first gripper 51, a second gripper 52, and a pressure sensor 53. The first gripper 51 is mounted on the first lead screw slider 35 of the transmission structure 3 of the clamping mechanism. The second gripper 52 is mounted on the second lead screw slider 36 of the transmission structure 3 of the clamping mechanism. The pressure sensor 53 is mounted on the second gripper 52, located between the first gripper 51 and the second gripper 52. The first gripper 51 and the second gripper 52 are matched, and both the first gripper 51 and the second gripper 52 are matched with the cutting assembly 4.

[0036] The operation method of this device is as follows: Assuming the target fruit is dragon fruit, the initial state of the clamping assembly 5 and the cutting assembly 4 is horizontally open, located at both ends of the guide structure 1. After the differential harvesting end effector approaches the dragon fruit, the drive motor 21 of the clamping mechanism rotates, which in turn drives the input shaft bevel gear 23 to rotate. The input shaft bevel gear 23 drives the revolution bevel gear 62 of the differential 6 to rotate. The revolution bevel gear 62 drives the differential housing 63 to rotate, which is the revolution of the planetary gear 66. Initially, when the clamping assembly 5 is not in contact with the fruit, the first gripper 51 and the second gripper 52 have the same load, and the two planetary gears 66 clamp the revolution bevel gear 62 and the half-shaft bevel gear 65 to rotate at the same speed and in the same direction. The second output bevel gear 64 and the first output bevel gear 61 rotate in opposite directions. The second output bevel gear 64 drives the second lead screw 34 to rotate in reverse via the second bevel gear 33, while the first output bevel gear 61 drives the first lead screw 32 to rotate in the forward direction via the first bevel gear 31. The first gripper 51 and the second gripper 52 move towards each other. If the first gripper 51 contacts the fruit first, it encounters resistance, and the second gripper 52 does not contact the fruit, resulting in a zero load. Under the revolution and rotation of the planetary gear 66, the moving speed of the first gripper 51, which is currently encountering resistance, decreases, and the power of the drive motor 21 is transferred to the second gripper 52, increasing its moving speed. When both the first gripper 51 and the second gripper 52 have gripped the fruit, the load difference between them decreases, and the difference in moving speed decreases until the force and speed on both sides of the fruit are balanced. The pressure sensor 53 detects the holding force between the first gripper 51 and the second gripper 52. When the set limit value is reached, the drive motor 21 of the clamping mechanism stops moving, completing the clamping of the fruit. The shearing mechanism operates on the same principle as the clamping mechanism. When the first cutter 41 contacts the fruit stem, the planetary gears 66 of the differential gear 6 revolve and rotate, causing the first cutter 41 to slow down and the second cutter 42 to speed up. When both the first cutter 41 and the second cutter 42 have contacted the fruit stem, the forces on both sides of the fruit stem are balanced, and the first cutter 41 and the second cutter 42 move at the same speed, thus completing the shearing of the fruit stem. The laser rangefinder 37 detects the distance between the first lead screw slider 35 and the second lead screw slider 36, respectively. When the distance between the first cutter 41 and the second cutter 42 is determined to be 0, the drive motor 21 of the shearing mechanism stops running, completing the harvesting of the fruit.

[0037] The above-described specific embodiments are preferred embodiments of the present invention and are not intended to limit the present invention. Any other changes or equivalent substitutions made without departing from the technical solution of the present invention are included within the protection scope of the present invention.

Claims

1. A differential harvesting end effector integrating clamping and shearing, characterized in that: The device includes a guide structure, a drive structure, a differential, a transmission structure, a cutting assembly, and a clamping assembly. The drive structure is mounted on the side of the guide structure and is connected to the transmission structure via the differential. The differential is mounted on the guide structure via a differential mounting bracket. The cutting assembly is movably mounted on one of the guide structures via one of the transmission structures, and the clamping assembly is movably mounted on another guide structure via another transmission structure. The two guide structures are connected in parallel. The differential includes a second output bevel gear, a revolution bevel gear, an input bevel gear, a differential housing, a first output bevel gear, a half-shaft bevel gear, and planetary gears. The second output bevel gear is connected to the revolution bevel gear via a rotating shaft. The revolution bevel gear is connected to the differential housing. The input bevel gear is located at the center of the revolution bevel gear. The planetary gears are rotatably mounted inside the differential housing. The input bevel gear is connected to the half-shaft bevel gear via the planetary gears. The half-shaft bevel gear is connected to the first output bevel gear via a rotating shaft. Both the first output bevel gear and the second output bevel gear are connected to the transmission structure. The rotating shaft is rotatably mounted on the differential mounting base. The transmission structure includes a first bevel gear, a first lead screw, a second bevel gear, a second lead screw, a first lead screw slider, a second lead screw slider, and a laser rangefinder sensor. Both the first and second lead screws are rotatably mounted on the guide structure. The first lead screw is connected to one end of the differential via the first bevel gear, and the second lead screw is connected to the other end of the differential via the second bevel gear. The first lead screw slider is threaded to the first lead screw, and the second lead screw slider is threaded to the second lead screw. Both the first and second lead screw sliders are slidably mounted on the guide structure. The laser rangefinder sensor is mounted at both ends of the guide structure. Both the first and second lead screw sliders correspond to the laser rangefinder sensor. One first lead screw slider and one second lead screw slider are connected to the cutting assembly, and the other first lead screw slider and the other second lead screw slider are connected to the clamping assembly.

2. The differential-speed picking end effector with integrated clamping and shearing as described in claim 1, characterized in that: The guiding structure includes a first lead screw fixing seat, a base plate, a second lead screw fixing seat, a first guide rod, and a second guide rod. The first lead screw fixing seat and the second lead screw fixing seat are both installed at both ends of the base plate. One end of the first guide rod and one end of the second guide rod are both installed in the first lead screw fixing seat, and the other end of the first guide rod and the other end of the second guide rod are both installed in the second lead screw fixing seat. The transmission structure is slidably connected to the first guide rod and the second guide rod, respectively. Both ends of the transmission structure are rotatably installed in the first lead screw fixing seat and the second lead screw fixing seat. The drive structure is connected to the base plate, and the differential fixing seat is installed in the first lead screw fixing seat.

3. The differential-speed picking end effector integrating clamping and shearing according to claim 1, characterized in that: The drive structure includes a drive motor, a motor bracket, and an input shaft bevel gear. The drive motor is mounted on the guide structure via the motor bracket, and the drive motor is connected to the differential via the input shaft bevel gear.

4. The differential-speed picking end effector integrating clamping and shearing according to claim 1, characterized in that: The cutting assembly includes a first cutting blade and a second cutting blade, both of which are mounted on a transmission structure and are matched.

5. The differential-speed picking end effector integrating clamping and shearing according to claim 1, characterized in that: The clamping assembly includes a first jaw, a second jaw, and a pressure sensor. The first jaw and the second jaw are both mounted on another of the transmission structures. The pressure sensor is mounted on the second jaw and is located between the first jaw and the second jaw. The first jaw and the second jaw are matched.

6. The differential-speed picking end effector integrating clamping and shearing according to claim 1, characterized in that: It also includes a robotic arm mounting bracket, which is connected to a guide structure.

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