An integrated end effector for harvesting of hard-shell fruits

Abstract

The application provides a harvesting integrated end effector for hard-shelled fruits, which can grasp, twist and collect fruits, has a compact structure and high harvesting efficiency, and comprises a rotating inner cylinder coaxially arranged on a base outer cylinder, a moving ring frame threadedly connected to the front end of the rotating inner cylinder, a motor driving the rotating inner cylinder to rotate through a transmission mechanism arranged on the outer peripheral portion of the rotating inner cylinder, a friction ring slidingly arranged in a friction groove on the base outer cylinder, and a plurality of fingers arranged on the outer peripheral portion of the front portion of the rotating inner cylinder, wherein the rear end of each finger is hingedly connected to the moving ring frame and the front end of a connecting rod respectively at the inner side end close to the axis of the rotating inner cylinder and the outer side end away from the axis of the rotating inner cylinder in the radial direction, and the rear end of the connecting rod is hingedly connected to the friction ring. The cylindrical structure twisting mechanism driven by a single motor can realize the functions of continuous picking and collecting, reduces the fruit collecting link, and has high harvesting efficiency.

Description

Technical Field

[0001] This invention belongs to the field of harvesting technology, specifically a harvesting end effector for hard-shelled fruits. Background Technology

[0002] Fruit harvesting requires a significant labor input, resulting in high costs. With advancements in robotics and artificial intelligence, harvesting robots have emerged as an alternative to manual labor. These robots mimic human harvesting methods, first picking the fruit and then placing it for collection—a necessary step for fruits with fragile surfaces. However, the time spent on collection after each harvest can sometimes exceed the time spent picking. For hard-shelled fruits, such as walnuts and camellia oleifera, separate collection is unnecessary; they can be achieved through pipes or netting.

[0003] Chinese patent CN117140573A discloses a single-drive, two-stage rotary gripper for picking fruit, comprising a clamping mechanism, a primary twisting mechanism, a secondary twisting mechanism, and a drive mechanism. The clamping mechanism includes multiple gripping claws and finger supports. The primary twisting mechanism includes a helical shell. The secondary twisting mechanism includes a frame, adjusting bolts, friction blocks, adjusting springs, and adjusting nuts. The drive mechanism includes a motor, a first bushing, and a second bushing. The motor's output shaft is connected to the first bushing, and the first bushing is connected to the second bushing. The second bushing is covered by a helical shell, and its end is connected to the finger support. The machine includes a base, a finger base, and a spiral shell that can rotate relative to each other. The finger base is rotatably connected to a gripper, and each gripper has a ball head at its end. The spiral shell has multiple arc-shaped grooves on its surface facing the end of the gripper, the same number as the ball heads. The ball heads are slidably connected to the arc-shaped grooves. The machine includes a frame and a pair of clamping cylinders symmetrically arranged on the frame. The piston rods of the two clamping cylinders are opposite each other. The ends of the piston rods of the clamping cylinders are rotatably connected to corresponding clamping plates. The clamping working surface of the clamping plate has an arc-shaped structure to cooperate with the tree trunk being clamped.

[0004] The aforementioned mechanism uses a single motor to drive a clamping mechanism, a first-stage twisting mechanism, and a second-stage twisting mechanism to grasp and twist the fruit. It has a simple structure and strong picking ability. However, the gripper is not designed with a matching collection function. The picked fruit still needs to be collected by a separate collection mechanism, which limits the picking efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an integrated harvesting end effector for hard-shelled fruits. It can grasp and twist hard-shelled fruits and provide a path for the fruits to fall along the rotating inner cylinder. It integrates fruit picking and collection functions, has a compact structure, high harvesting efficiency, simple and compact overall structure, small size, light weight, and is easy to use and operate, thus solving the above-mentioned problems.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] An integrated harvesting end effector for hard-shelled fruits includes a clamping mechanism, a screwing mechanism, and a drive mechanism;

[0008] The clamping mechanism includes multiple fingers; the screwing mechanism includes a rotating inner cylinder 2, a base outer cylinder 1, a moving ring frame 9, a connecting rod, a friction ring 6, an adjusting bolt 15, and an adjusting nut 13; the driving mechanism includes a motor and a transmission mechanism.

[0009] The rotating inner cylinder 2 is coaxial with the base outer cylinder 1 and is rotatably mounted on the base outer cylinder 1. The rotating inner cylinder 2 extends beyond the front end of the base outer cylinder 1 and is connected to the movable ring frame 9 by a threaded connection.

[0010] The motor is fixed on the outer cylinder 1 of the base, and the motor drives the inner cylinder 2 to rotate coaxially with respect to the outer cylinder 1 of the base through a transmission mechanism located on the outer periphery of the inner cylinder 2.

[0011] The outer circumference of the base outer cylinder 1 is provided with a friction groove 1-2. The friction ring 6 is slidably disposed in the friction groove 1-2. The friction ring 6 has buckles at two opposite ends in the circumferential direction. Bolt holes are provided on the buckles. An adjusting bolt 15 passes through the bolt holes on the two buckles and is connected to an adjusting nut 13. The friction force between the friction ring 6 and the friction groove 1-2 can be adjusted by adjusting the adjusting bolt 15 and the adjusting nut 13.

[0012] Multiple fingers are located on the outer periphery of the front part of the rotating inner cylinder 2. The rear end of each finger is hinged to the moving ring frame 9 and the front end of the connecting rod respectively in the radial direction, with the inner end close to the axis of the rotating inner cylinder 2 and the outer end away from the axis of the rotating inner cylinder 2. The rear end of the connecting rod is hinged to the friction ring 6.

[0013] In the aforementioned harvesting end effector for hard-shelled fruits, the adjusting bolt 15 is fitted with an adjusting spring 14. The bolt head of the adjusting bolt 15 and the adjusting spring 14 are respectively located at two circumferentially opposite latches. The adjusting spring 14 is located between the adjusting nut 13 and one latch or between the bolt head and another latch.

[0014] The aforementioned harvesting end effector for hard-shelled fruits has a friction ring 6 consisting of three sections, with each section having lugs at both ends that are circumferentially opposite to the other two sections.

[0015] The aforementioned harvesting end effector for hard-shelled fruits has three fingers and three connecting rods. Each friction ring has a connecting rod mounting groove in the middle, and the rear end of each connecting rod is hinged to a connecting rod mounting groove in the middle of a friction ring.

[0016] The aforementioned harvesting end effector for hard-shelled fruits includes a transmission mechanism comprising a synchronous belt and a synchronous pulley; the motor output shaft is connected to the synchronous pulley, and the synchronous pulley meshes with the synchronous teeth on the outer circumference of the rotating inner cylinder 2 via the synchronous belt.

[0017] The aforementioned harvesting end effector for hard-shelled fruits has a synchronizing gear located on the outer periphery of the rear end of the rotating inner cylinder 2 extending out of the base outer cylinder 1, and a synchronizing belt protective cover is installed on the base outer cylinder 1 to cover the synchronizing belt.

[0018] The aforementioned harvesting end effector for hard-shelled fruits has a finger support 11 fixed to the rear end of each finger, a connecting block 8 fixed to the rear end of each finger support 11, and the inner and outer ends of the rear end of each connecting block 8 are respectively hinged to a movable ring frame 9 and a connecting rod front end.

[0019] The aforementioned harvesting end effector for hard-shelled fruits consists of a connecting block 8 composed of four identical stepped shafts and two identical fixing plates. The fixing plates are machined with four stepped bearing holes and two bolt holes. The two fixing plates are located at both ends of the stepped shafts. The bolts pass through the bolt holes in the two fixing plates and are connected to nuts. The front end of the moving ring frame 9 and the front end of the connecting rod are respectively hinged to the stepped shafts on the connecting block 8.

[0020] The aforementioned harvesting end effector for hard-shelled fruits has a limit ring 10 fixed at the front end of the rotating inner cylinder 2 at the front of the moving ring frame 9.

[0021] The aforementioned harvesting end effector for hard-shelled fruits uses two bearings to connect the rotating inner cylinder 2 and the base outer cylinder 1. The outer circumference of the rotating inner cylinder 2 is machined with a snap ring groove 2-2. The two bearings are respectively limited by the shoulders on the base outer cylinder 1 and the rotating inner cylinder 2 and the snap ring located in the snap ring groove 2-2.

[0022] In the aforementioned harvesting end effector for hard-shelled fruits, the inner circumference of the friction ring 6 is an arc-shaped friction plate.

[0023] The beneficial effects achieved by this invention are as follows:

[0024] In this invention, the motor drives the rotating inner cylinder 2 to rotate relative to the base outer cylinder 1 through a transmission mechanism located on the outer periphery of the rotating inner cylinder 2. The rotation of the rotating inner cylinder 2 can drive the movable ring frame 9, which is threadedly engaged with the rotating inner cylinder 2, to move along the axial direction or rotate around the axial direction. However, before the fingers grasp the fruit, the rotational torque of the rotating inner cylinder 2 on the moving ring frame 9 is less than the static frictional torque generated between the friction ring 6 and the friction groove 1-2 of the base outer cylinder, which is the whole consisting of the moving ring frame 9, the connecting rod, and the friction ring 6. At this time, the friction ring 6 remains stationary relative to the friction groove 1-2, and the moving ring frame 9 only moves backward along the axis of the rotating inner cylinder 2. Under the action of the moving ring frame 9 and the connecting rod, the finger tip swings radially inward along the axis of the rotating inner cylinder 2 to achieve finger closure. When the fingers grasp the fruit, the motor is still rotating, but the fingers cannot continue to close. At this time, the rotational torque of the moving ring frame 9 and the rotating inner cylinder 2 gradually increases. When the torque on the rotating inner cylinder 2 is greater than the frictional torque between the friction ring 6 and the friction groove 1-2, the rotating inner cylinder 2, the moving ring frame 9, the connecting rod, the friction ring 6, the fingers, and the fruit are relatively fixed and continue to rotate with the rotating inner cylinder 2, thereby driving the fruit to rotate and realizing the twisting action, so that the fruit is separated from the stem.

[0025] During the harvesting of the next fruit, the end effector is adjusted so that the fingertip faces upwards. The motor reverses direction, and the rotational torque of the moving ring frame 9 from the rotating inner cylinder 2 is less than the static friction torque generated between the friction ring 6 and the friction groove 1-2 of the base outer cylinder, which is the entire assembly of the moving ring frame 9, connecting rod, and friction ring 6. At this time, the friction ring 6 remains stationary relative to the friction groove 1-2, and the moving ring frame 9 can only move forward along the axis of the rotating inner cylinder 2. Under the action of the moving ring frame 9 and connecting rod, the fingertip swings outwards radially away from the axis of the rotating inner cylinder 2, opening the finger and releasing the fruit. The fallen fruit then falls through the through hole inside the rotating inner cylinder 2 for collection, achieving integrated fruit harvesting and collection. Therefore, the end effector designed in this invention, driven by a single motor, integrates fruit harvesting and collection functions, has a compact structure, and high harvesting efficiency.

[0026] The present invention adjusts the distance between the circumferentially opposite buckles of the friction ring 6 by adjusting the bolt 15 and the adjusting nut 13, thereby adjusting the static friction between the friction ring 6 and the friction groove 1-2, and indirectly adjusting the gripping force of the fingers on the fruit.

[0027] This invention can also control the maximum opening degree of the fingers by adjusting the position of the limiting ring 10 in the axial direction of the rotating inner cylinder 2. This invention can be used for harvesting hard-shelled fruits, with high harvesting efficiency and a high degree of automation; and the post-harvest fruit collection speed is fast, saving additional fruit collection time. Attached Figure Description

[0028] Figure 1This is a schematic diagram of the harvesting-integrated end effector structure in an embodiment of the present invention. Figure 1 ;

[0029] Figure 2 This is a schematic diagram of the harvesting-integrated end effector structure in an embodiment of the present invention. Figure 2 (Remove the timing belt protective cover, etc.);

[0030] Figure 3 This is a side view of the harvesting-integrated end effector structure in an embodiment of the present invention;

[0031] Figure 4 This is a front view of the harvesting-integrated end effector structure in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the rotating inner cylinder structure;

[0033] Figure 6 This is a schematic diagram of the base outer cylinder structure;

[0034] Figure 7 It is a 3D diagram of the connecting blocks;

[0035] Figure 8 This is a structural diagram of the harvesting-integrated end effector used in this invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1—Base outer cylinder; 1-1—Mounting hole; 1-2—Friction groove; 1-3—Protective cover mounting hole; 2—Rotating inner cylinder; 2-1—Rotating inner cylinder threaded end; 2-2—Snap ring groove; 2-3—Synchronous gear; 3—Motor; 4—Synchronous pulley; 5—Synchronous belt; 6—Friction ring; 7—Connecting rod; 8—Connecting block; 8-1—Stepped shaft; 8-2—Fixing plate; 9—Moving ring frame; 10—Limiting ring; 11—Finger bracket; 12—Finger; 13—Adjusting nut; 14—Adjusting spring; 15—Adjusting bolt; 16—Snap ring; 17—Bearing; 18—Synchronous belt protective cover; 19—Snap ring. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings. It should be understood that the following specific embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0039] An integrated harvesting end effector for hard-shelled fruits includes a clamping mechanism, a screwing mechanism, and a drive mechanism;

[0040] The clamping mechanism includes multiple fingers and finger supports 11; the screwing mechanism includes a rotating inner cylinder 2, a base outer cylinder 1, a moving ring frame 9, a limiting ring 10, a connecting block 8, a connecting rod, a friction ring 6, an adjusting bolt 15, an adjusting spring 14, and an adjusting nut 13; the driving mechanism includes a motor 3, a synchronous pulley 4, a synchronous belt 5, and a synchronous belt protective cover 18.

[0041] The motor 3 is connected to the outer cylinder 1 of the base and is fixed on the outer cylinder 1. The output shaft of the motor is connected to the synchronous pulley 4. The synchronous pulley 4 is connected to the toothed end of the rotating inner cylinder 2 via a synchronous belt 5. The synchronous belt protective cover 18 is installed on the outer cylinder 1 of the base. The rotating inner cylinder 2 is coaxially rotatably connected to the outer cylinder 1 of the base and can rotate relative to the axis of the outer cylinder 1 of the base.

[0042] The outer wall of the base outer cylinder 1 is provided with a circular friction groove 1-2. The friction ring 6 is installed in the friction groove 1-2. The friction ring 6 has lugs on both sides, and bolt holes are provided on the lugs. The adjusting bolt 15 passes through the bolt holes on the lugs of two adjacent friction rings 6. The adjusting bolt 15 is threadedly connected to the adjusting nut 13. The adjusting bolt 15 is fitted with an adjusting spring 14. The bolt head of the adjusting bolt 15 and the adjusting spring 14 are respectively located at the lugs of two adjacent friction rings 6. The adjusting spring 14 is located between one lug and the adjusting nut 13. The friction ring 6 is provided with a connecting rod mounting groove in the middle. The connecting rod mounting groove has round holes on both sides. The connecting rod 7 has through holes at both ends. The rear end of the connecting rod 7 is installed in the connecting rod mounting groove of the friction ring 6. The bolt shank of the half-threaded bolt passes through one side of the connecting rod mounting groove, the round hole at the rear end of the connecting rod, and the other side of the connecting rod mounting groove in sequence. The half-threaded bolt is connected to the nut.

[0043] The front end of the connecting rod 7 is connected to the connecting block 8. The connecting block 8 and the connecting rod can rotate relative to each other. A finger support 11 is fixed on the connecting block 8, and a finger 12 is mounted on the finger support 11.

[0044] Furthermore, the connecting block 8 consists of four identical stepped shafts 8-1 and two identical fixing plates 8-2. The fixing plates 8-2 are machined with four stepped bearing holes and two bolt holes. The two fixing plates are located at both ends of the stepped shafts 8-1. The bolts pass through the bolt holes in the two fixing plates respectively, and the bolts are connected with nuts.

[0045] Furthermore, the outer cylinder of the base is provided with protective cover mounting holes 1-3, and the synchronous belt protective cover 18 is connected to the outer cylinder of the base by bolts and nuts passing through the protective cover mounting holes 1-3.

[0046] Furthermore, the outer wall of the front end of the rotating inner cylinder 2 is threaded, and the inner wall of the movable ring frame 9 is threaded in the same way. The movable ring frame 9 and the rotating inner cylinder 2 are connected by threads.

[0047] Furthermore, a limit ring 10 is installed at the threaded top of the rotating inner cylinder 2.

[0048] Furthermore, the motor housing is fixed to the motor bracket of the base outer cylinder 1 by screws.

[0049] Furthermore, the synchronous pulley 4 is engaged with the motor output shaft via a flat key, and the synchronous pulley 4 is tightly connected to the motor output shaft via a set screw.

[0050] Furthermore, the rotating inner cylinder 2 and the base outer cylinder 1 are connected by two bearings 17. The outer wall of the rotating inner cylinder 2 is machined with a snap ring groove 2-2. The two bearings are respectively limited by the shoulders on the base outer cylinder 1 and the rotating inner cylinder 2 and the snap ring 19 located in the snap ring groove 2-2.

[0051] Furthermore, the inner side of the friction ring 6 is an arc-shaped friction plate, and the friction ring 6 can only slide within the friction groove 1-2 of the base sleeve.

[0052] Furthermore, there are three of each of the following components: friction ring 6, adjusting bolt 15, adjusting nut 13, adjusting spring 14, connecting rod 7, connecting block 8, finger support 11, and finger 12.

[0053] Furthermore, the finger 12 is made of a flexible material and is attached to the finger support 11.

[0054] Furthermore, the outer cylinder 1 of the base is provided with four mounting holes 1-1.

[0055] The motor of this invention drives the rotating inner cylinder 2 to rotate relative to the base outer cylinder 1 via a synchronous pulley and a synchronous belt. The rotation of the rotating inner cylinder 2 can drive the movable ring frame 9 on the thread of the rotating inner cylinder 2 to move or rotate along the axial direction. However, before the fingers grasp the fruit, the rotational torque of the movable ring frame 9 on the rotating inner cylinder 2 is less than the static friction torque generated between the friction ring 6 and the friction groove 1-2 of the base outer cylinder 1 on the entire assembly of the movable ring frame 9, connecting block 8, connecting rod and friction ring 6. At this time, the movable ring frame 9 will only move along the axis of the rotating inner cylinder 2 to achieve the closing of the fingers. When the fingers grasp the fruit, the motor is still rotating, and the fingers cannot continue to close. At this point, the rotating inner cylinder 2, the moving ring frame 9, the connecting block 8, the connecting rod, the friction ring 6, the finger support 11, the finger, and the fruit are relatively fixed. When the torque on the rotating inner cylinder 2 is greater than the friction force between the friction ring 6 and the friction groove 1-2 of the base outer cylinder 1, the rotating inner cylinder 2 will continue to rotate, thereby driving the fruit to rotate and achieving a twisting action, separating the fruit from the fruit stem. A collection pipe can be connected to one side of the rotating through hole. During the harvesting of the next fruit, the end effector is adjusted so that the finger faces upward, and the motor reverses to make the finger release the fruit. The fallen fruit can then be collected through the through hole inside the rotating inner cylinder 2, realizing the integration of fruit harvesting and collection. Therefore, the end effector designed in this invention is driven by a single motor and integrates the functions of fruit harvesting and collection. It has a compact structure and high harvesting efficiency. This invention can indirectly adjust the gripping force of the finger by adjusting the static friction force between the friction ring 6 and the friction groove 1-2 of the base outer cylinder 1. This invention can also control the maximum opening of the finger by adjusting the position of the limiting ring 10. This technology can be used for harvesting hard-shelled fruits, with high harvesting efficiency and a high degree of automation; moreover, the post-harvest collection speed is fast, saving additional fruit collection time.

[0056] This invention utilizes a single-motor driven cylindrical screw mechanism to achieve continuous picking and collection, reducing fruit collection steps and increasing harvesting efficiency.

[0057] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A harvesting end effector for hard-shelled fruits, characterized in that: Includes clamping mechanism, screwing mechanism, and drive mechanism; The clamping mechanism includes multiple fingers; the screwing mechanism includes a rotating inner cylinder (2), a base outer cylinder (1), a moving ring frame (9), a connecting rod, a friction ring (6), an adjusting bolt (15), and an adjusting nut (13); the driving mechanism includes a motor and a transmission mechanism. The rotating inner cylinder (2) is coaxial with the base outer cylinder (1) and rotates inside the base outer cylinder (1). The rotating inner cylinder (2) extends beyond the front end of the base outer cylinder (1) and is connected to the movable ring frame (9) by a thread. The motor is fixed on the outer cylinder (1) of the base, and the motor drives the inner cylinder (2) to rotate coaxially with respect to the outer cylinder (1) of the base through a transmission mechanism located on the outer periphery of the inner cylinder (2); The outer circumference of the base outer cylinder (1) is provided with a friction groove (1-2). The friction ring (6) is slidably disposed in the friction groove (1-2). The friction ring (6) includes three sections. Each section of the friction ring has a buckle at both ends that is circumferentially opposite to the other two sections. The buckle is provided with a bolt hole. An adjusting bolt (15) passes through the bolt hole on the two buckles and is connected to an adjusting nut (13). The friction force between the friction ring (6) and the friction groove (1-2) is adjusted by adjusting the adjusting bolt (15) and adjusting nut (13). Multiple fingers are located on the outer periphery of the front part of the rotating inner cylinder (2). The rear end of each finger is hinged to the moving ring frame (9) and the front end of the connecting rod respectively on the inner side of the rotating inner cylinder (2) and the outer side of the rotating inner cylinder (2) away from the axis of the rotating inner cylinder (2). The rear end of the connecting rod is hinged to the friction ring (6).

2. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: The adjusting bolt (15) is fitted with an adjusting spring (14). The bolt head of the adjusting bolt (15) and the adjusting spring (14) are respectively located at two circumferentially opposite latches. The adjusting spring (14) is located between the adjusting nut (13) and one latch or between the bolt head and another latch.

3. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: There are three fingers and three connecting rods. Each friction ring has a connecting rod mounting groove in the middle, and the rear end of each connecting rod is hinged to a connecting rod mounting groove in the middle of a friction ring.

4. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: The transmission mechanism includes a synchronous belt and a synchronous pulley; the motor output shaft is connected to the synchronous pulley, and the synchronous pulley meshes with the synchronous teeth on the outer circumference of the rotating inner cylinder (2) through the synchronous belt.

5. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: A finger support (11) is fixed to the rear end of each finger, and a connecting block (8) is fixed to the rear end of each finger support (11). The inner and outer ends of the rear end of each connecting block (8) are respectively hinged to the movable ring frame (9) and the front end of a connecting rod.

6. The harvesting end effector for hard-shelled fruits as described in claim 5, characterized in that: The connecting block (8) consists of four identical stepped shafts and two identical fixed plates. The fixed plates are machined with four stepped bearing holes and two bolt holes. The two fixed plates are located at both ends of the stepped shafts. The bolts pass through the bolt holes in the two fixed plates respectively, and the bolts are connected with nuts. The front end of the moving ring frame (9) and the front end of the connecting rod are respectively hinged to the stepped shafts on the connecting block (8).

7. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: in The front end of the rotating inner cylinder (2) at the front of the movable ring frame (9) is fixed with a limit ring (10).

8. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: The rotating inner cylinder (2) and the base outer cylinder (1) are connected by two bearings. The outer circumference of the rotating inner cylinder (2) is machined with a snap ring groove (2-2). The two bearings are respectively limited by the shoulders on the base outer cylinder (1) and the rotating inner cylinder (2) and the snap ring located in the snap ring groove (2-2).

9. The harvesting end effector for hard-shelled fruits as described in claim 1, characterized in that: The inner circumference of the friction ring (6) is an arc-shaped friction plate.

Images