A small soft blueberry picking robot

Abstract

The application discloses a small soft blueberry picking robot, which comprises a double-helix soft picking mechanism, a feeding mechanical arm for grabbing blueberry branches and feeding them into the double-helix soft picking mechanism, and a collecting frame; at least one pair of helical shafts are rotationally arranged at the front side entrance of the material bin of the double-helix soft picking mechanism, and the two helical shafts are driven to rotate in opposite directions by a driving assembly; a plurality of soft prongs are distributed on the helical shafts, and the soft prongs are configured to be able to pick mature blueberries while avoiding the shedding of unripe fruits; when the two helical shafts rotate synchronously towards the inside, the soft prongs on the two helical shafts can simulate the action of picking by hand to pick the mature blueberries off the blueberry branches; when the two helical shafts rotate synchronously towards the outside, the soft prongs on the two helical shafts release the blueberry branches; and the guide hopper of the double-helix soft picking mechanism collects the picked blueberries from the material bin into the collecting frame. The application can realize efficient and high-quality blueberry picking and avoid damage to the fruit trees.

Description

Technical Field

[0001] This invention relates to blueberry picking robots, specifically to a small, soft blueberry picking robot. Background Technology

[0002] Greenhouse blueberry cultivation mainly consists of potted blueberries and dwarf blueberries, characterized by high planting density and small plant spacing. Existing blueberry harvesting equipment mainly consists of vibrating or comb-type blueberry harvesters. These two types of blueberry harvesting equipment are relatively large and require a certain amount of planting space for blueberry plants, making them unsuitable for the aforementioned harvesting scenarios. Therefore, greenhouse blueberry harvesting is still mainly done manually. As the planting area of ​​blueberries expands, the demand for harvesters is also increasing, especially during the peak harvesting season when it is difficult to find harvesters. At the same time, manual harvesting is costly for growers. Growers urgently need a flexible, small-scale blueberry harvesting device. Existing technology (Wang Tianyun et al. Design and application of intelligent blueberry harvesting robot [J]. Engineering Machinery, 2024, 56(6): 150-153) discloses a small blueberry harvesting robot with a walking mechanism and a harvesting device. The harvesting device adopts a multi-segment mechanical arm structure with a gripper at the end. The technical problem is that the grippers can easily damage the blueberries when picking them directly, and the picking efficiency is low. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a small, soft blueberry picking robot that has high picking efficiency and can avoid damaging blueberry fruits during picking.

[0004] Technical solution: The present invention provides a small soft blueberry picking robot, which has a frame and a walking mechanism. The frame is equipped with a feeding robotic arm, a double helix soft picking mechanism and a collection frame.

[0005] The double-helix soft-harvesting mechanism includes a hopper and a guide hopper. At least one pair of spiral shafts are rotatably arranged at the front inlet of the hopper, and a harvesting opening is formed between the two pairs of spiral shafts. Each pair of spiral shafts is equipped with a drive assembly. Several soft fingers are distributed on the spiral shafts. The soft fingers are configured to pick ripe blueberries and prevent unripe fruits from falling off.

[0006] The feeding robotic arm is used to grasp blueberry branches and feed them into the double-helix soft-tip harvesting mechanism; the drive assembly is used to drive the two helical shafts to rotate synchronously inward, so that the soft fingers on the two helical shafts can simulate the picking action of a human hand, pushing the blueberry branches into the harvesting opening and removing the ripe blueberries from the branches; or drive the two helical shafts to rotate synchronously outward, so that the soft fingers on the two helical shafts release the blueberry branches; the guide hopper is used to collect the harvested blueberries from the hopper into the collection frame.

[0007] Furthermore, the soft shifter adopts a first soft shifter, and several first soft shifters are spirally distributed on the helical shaft; the first soft shifter includes a root structure, an elastomer, and a spherical soft body connected in sequence, and the root structure is detachably connected to the helical shaft; a rubber finger sleeve is fitted on the first soft shifter, and a circular protrusion structure for fixing the rubber finger sleeve is provided on the root structure; the elastic force of the first soft shifter is determined by test.

[0008] Furthermore, the soft shifter adopts a second soft shifter, and a plurality of second soft shifters are distributed at intervals on the helical shaft, and the second soft shifters on the two helical shafts are staggered from each other;

[0009] The second soft-touch finger is a centrally symmetrical teardrop-shaped handle structure. It has a circular hole at its center that fits with the auger shaft with a clearance. An internally threaded hole communicating with the circular hole is opened on the side of the circular hole. A plunger is threaded into the internally threaded hole. The outer end of the plunger has an internal hexagonal hole to facilitate the rotation of the plunger. The inner end of the plunger is a hollow structure and is equipped with a spring. The end of the spring is connected to a hemisphere, which contacts the circumferential surface of the auger shaft. The frictional resistance between the teardrop-shaped handle structure and the auger shaft is determined by rotating the plunger and by testing. The end of the teardrop-shaped handle structure has a smooth transition section with a small cross-section.

[0010] Furthermore, the hopper includes two fan-shaped side plates that are arranged opposite to each other and rotatably connected to the top of the frame. A top crossbeam and a bottom plate are connected between the two fan-shaped side plates. The front inlet of the hopper is formed by the top crossbeam, the bottom plate and the two fan-shaped side plates. The rear end of the bottom plate extends into the guide hopper.

[0011] Furthermore, the drive assembly is fixed below the base plate and has two output ends with opposite directions of rotation; one end of each of the two helical shafts is connected to the two output ends of the drive assembly, and the other end of each of the two helical shafts is detachably rotatably connected to the top crossbeam.

[0012] Furthermore, the drive assembly includes a second motor, a drive assembly housing, and a drive gear, a large intermediate gear, a small intermediate gear, a first driven gear, a transition gear, and a second driven gear rotatably disposed inside the drive assembly housing. The large intermediate gear and the small intermediate gear are coaxially arranged, with the large intermediate gear meshing with the drive gear and the first driven gear respectively, and the transition gear meshing with the small intermediate gear and the second driven gear respectively. The second motor is fixed to the outside of the drive assembly housing, and the output end of the second motor extends into the drive assembly housing and is connected to the drive gear. One end of each of the two helical shafts is detachably connected to the output shafts of the first driven gear and the second driven gear respectively.

[0013] Furthermore, the spiral shaft connected to the output shaft of the first driven gear is configured to be movable, enabling adjustment of the distance between the two spiral shafts; an arc-shaped groove is provided on the drive assembly housing for the sliding output shaft of the first driven gear to slide, with the center of the large intermediate gear as the center; a positioning pin hole is provided at the other end of the first driven gear output shaft, which is hinged to a positioning screw, and the positioning screw is tightly connected to the drive assembly housing to restrict the position of the first driven gear; a second end plate is provided on the outer side of the top crossbeam, and an arc-shaped guide groove is opened on the end face of the second end plate, with the ball-shaped structure at the other end of the spiral shaft embedded in the guide groove. The second end plate axially limits the other end of the spiral shaft, while the spiral shaft can rotate; an arc-shaped groove for the spiral shaft to move is also provided on the top crossbeam.

[0014] Furthermore, the double-helix soft-harvesting mechanism is equipped with linear modules on both sides, and the feeding robotic arm is mounted on the linear modules. The linear modules are used to adjust the height of the feeding robotic arm to adapt to blueberry plants of different heights.

[0015] Furthermore, the gripper assembly at the end of the feeding robotic arm has two openable grippers, the surface of which is made of a soft material; protrusions and grooves are alternately arranged on the opposite sides of the two grippers from the outside to the inside, and the grooves gradually decrease in size from the outside to the inside to accommodate the gripping of blueberry branches of different diameters; the opposite ends of the two grippers are connected by a sheet-like soft strap, which, together with the two grippers, can adaptively wrap the blueberry branches.

[0016] Furthermore, a collection bag is inclinedly installed below the double helix soft-harvesting mechanism. One end of the collection bag extends to the front of the double helix soft-harvesting mechanism and curves upward, while the other end extends to the collection frame to collect scattered blueberries.

[0017] Beneficial Effects: Compared with existing technologies, this invention has the following significant advantages: This invention uses a rotating, biomimetic, flexible finger to simulate the picking action of human fingers, enabling efficient blueberry picking while avoiding damage to the fruit trees; simultaneously, through the selection of the soft finger design, ripe blueberries are picked while unripe berries fall off; thus, efficient and high-quality blueberry picking is achieved. This invention can be extended to the picking of other similar fruits, such as goji berries. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a small soft blueberry picking robot provided in an embodiment of the present invention;

[0019] Figure 2 yes Figure 1 Side view;

[0020] Figure 3 This is a schematic diagram of the linear module and the feeding robotic arm in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the gripper assembly in an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the structure of the hopper, guide hopper and collection bag in an embodiment of the present invention;

[0023] Figure 6 This is a schematic diagram of the mating structure between the helical shaft and the drive assembly in an embodiment of the present invention;

[0024] Figure 7 This is a schematic diagram of the meshing structure between the gears inside the drive assembly housing in an embodiment of the present invention;

[0025] Figure 8 This is a schematic diagram of the structure of the first soft-touch finger in an embodiment of the present invention;

[0026] Figure 9 yes Figure 1 A magnified view of part A;

[0027] Figure 10 This is a schematic diagram of the cooperation structure between the spiral shaft, the top crossbeam, and the second end plate in an embodiment of the present invention;

[0028] Figure 11 This is a schematic diagram of the structure of the second soft-touch finger distributed on the spiral shaft in an embodiment of the present invention;

[0029] Figure 12 yes Figure 11 A magnified view of part B;

[0030] Figure 13 This is a schematic diagram of the walking mechanism in an embodiment of the present invention. Detailed Implementation

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] Appendix Figures 1 to 13 The accompanying figure labels are as follows:

[0033] 1. Rack; 11. Power supply; 12. Collection box; 13. Control cabinet; 14. Positioning plate;

[0034] 2. Linear module; 21. Mounting base; 22. Lead screw; 23. Guide post; 24. Lead screw nut; 25. Slider; 26. First motor;

[0035] 3. Feeding robotic arm; 31. Upper arm; 32. Lower arm; 33. Joint motor; 34. Wrist joint; 35. Gripper assembly; 351. Gripper body; 352. Sheet-shaped soft system belt; 353. Protrusion; 354. Groove;

[0036] 4. Double-helix soft-touch harvesting mechanism; 41. Hopper; 411. Fan-shaped side plate; 412. Top beam; 413. Bottom plate; 414. Partition plate; 415. V-shaped elastic pad; 42. Guide hopper; 43. Helical shaft; 44. Drive assembly; 441. Second motor; 442. Drive gear; 443. Large intermediate gear; 444. Small intermediate gear; 445. First driven gear; 446. Transition gear; 447. Second driven gear; 448. Arc groove; 45. First soft-touch finger; 451. Elastomer; 452. Spherical soft body; 453. Rubber finger sleeve; 46. First end plate; 47. Second end plate; 48. Second soft-touch finger; 481. Plunger;

[0037] 5. Collection pocket; 51. Support rod; 52. Elastic pocket body; 53. Elastic line;

[0038] 6. Panoramic image acquisition mechanism; 61. Binocular camera;

[0039] 7. Walking mechanism; 71. Front wheel; 72. Rear wheel; 73. Steering gear; 74. Wheel support arm; 75. Connecting rod.

[0040] like Figure 1 and Figure 2 As shown, this embodiment of the invention provides a small soft-stemmed blueberry harvesting robot, including a frame structure frame 1. A double-helix soft-stemmed harvesting mechanism 4 and two sets of linear modules 2 are mounted on the frame 1. The double-helix soft-stemmed harvesting mechanism 4 is located at the top front center of the frame 1, and the two sets of linear modules 2 are located on either side of the double-helix soft-stemmed harvesting mechanism 4. Each of the two sets of linear modules 2 is equipped with a feeding robotic arm 3, which is used to grasp blueberry branches and feed them into the double-helix soft-stemmed harvesting mechanism 4. The double-helix soft-stemmed harvesting mechanism 4 is used to harvest ripe blueberries from the blueberry branches. The linear modules 2 are used to adjust the height of the feeding robotic arms 3 to adapt to blueberry plants of different heights.

[0041] The frame 1 is equipped with a power supply 11 and a collection box 12. The power supply 11 powers the robot. The collection box 12 is located behind the power supply 11 and is used to collect blueberries picked by the double helix soft-tip harvesting mechanism 4. Several positioning plates 14 are provided on the bottom plate of the frame 1 to position the left, right and rear sides of the collection box 12 (the front side of the collection box 12 is positioned by the power supply 11), preventing the collection box 12 from slipping and facilitating the replacement of the collection box 12.

[0042] Most of the blueberries picked by the double helix soft-harvesting mechanism 4 can be collected into the collection frame 12, but inevitably some blueberries will scatter. To address this, a collection pocket 5 is inclinedly installed below the double helix soft-harvesting mechanism 4. One end of the collection pocket 5 extends to the front of the double helix soft-harvesting mechanism 4 and curves upward, while the other end extends into the collection frame 12. Thus, the collection pocket 5 can collect the scattered blueberries and deliver them into the collection frame 12.

[0043] The top of the two linear modules 2 is equipped with a panoramic image acquisition mechanism 6 using a bracket. The panoramic image acquisition mechanism 6 has a total of four sets of binocular cameras 61 (existing technology) arranged in four directions, which can realize the acquisition of images of blueberry plants and surrounding environment.

[0044] A walking mechanism 7 is installed at the bottom of the frame 1, which can perform straight-line movement and turning. A control cabinet 13 is installed on the top rear side of the frame 1. The control cabinet 13 is equipped with a memory and a processor. The memory stores specific algorithm programs, such as blueberry branch recognition algorithm, path planning algorithm, obstacle avoidance algorithm, and robotic arm pose control algorithm. The processor executes these algorithm programs to control the robot to perform specific actions, such as controlling the feeding robotic arm 3 to grab blueberry branches and deliver them to the double helix soft picking mechanism 4, and controlling the robot to move along the planned path and avoid obstacles.

[0045] The following is a detailed introduction to the components of the small soft blueberry picking robot.

[0046] (I) Linear Module 2

[0047] like Figure 3 As shown, the linear module 2 includes a mounting base 21, a slider 25, and a first motor 26. Inside the mounting base 21, a lead screw 22 and a guide post 23 are arranged side-by-side. The slider 25 passes through the lead screw 22 and the guide post 23, and is fixedly connected to the lead screw nut 24 on the lead screw 22. The feeding robotic arm 3 is mounted on the slider 25. The first motor 26 is mounted on the rear side of the mounting base 21. The output end of the first motor 26 is connected to the lead screw 22 via a transmission assembly, which uses a synchronous pulley or gear (not shown in the figure). The first motor 26 drives the lead screw 22 to rotate, causing the slider 25 to move up and down, thereby adjusting the height of the feeding robotic arm 3. When using a bracket to install the panoramic image acquisition mechanism 6, the bracket must avoid the transmission assembly.

[0048] (II) Feeding robotic arm 3

[0049] like Figure 3 As shown, the feeding robotic arm 3 includes a large arm 31 and a small arm 32. The two ends of the large arm 31 are connected to a slider 25 and the small arm 32 respectively via articulated motors 33. A wrist joint 34 is rotatably connected to the end of the small arm 32, and this wrist joint 34 is driven to rotate by an articulated motor inside the small arm 32. A rotary drive component is provided at the front end of the wrist joint 34, and a gripper assembly 35 is installed at the output end of the rotary drive component. This rotary drive component can drive the gripper assembly 35 to rotate. In this embodiment, the rotary drive component uses a rotary motor.

[0050] By driving the corresponding arm segment rotation via the articulated motor 33, the position of the feeding robotic arm 3 can be adjusted so that the gripper assembly 35 reaches the target blueberry branch. By rotating the wrist joint 34 and the gripper assembly 35, the gripper assembly 35 can be adjusted to a suitable angle for grasping the target blueberry branch.

[0051] like Figure 4 As shown, the gripper assembly 35 includes a gripper body and two identical claw bodies 351 rotatably mounted on the gripper body. The two claw bodies 351 are driven to open and close by a linear motor joint module inside the gripper body. The surface of the claw bodies 351 is made of a soft material to prevent damage to the blueberry branches. The opposite sides of the two claw bodies 351 are alternately provided with protrusions 353 and grooves 354 from the outside in. The grooves 354 gradually decrease in size from the outside in to accommodate blueberry branches of different diameters. The opposite ends of the two claw bodies 351 are connected by a sheet-like soft strap 352, which, in conjunction with the two claw bodies 351, adaptively wraps around the blueberry branches. The gripper assembly 35 used in this embodiment has a large opening, requiring low visual positioning accuracy (i.e., low hardware and software requirements), thus helping to reduce equipment costs. The improvement of the gripper assembly 35 lies in the gripper body 351 and the sheet-like soft system belt 352. The gripper body and its internal structure are existing technologies and will not be described in detail here.

[0052] (III) Double Helix Soft Harvesting Mechanism 4

[0053] Combining 5 and Figure 6 The double helix soft-harvesting mechanism 4 includes a hopper 41, a guide hopper 42, a helical shaft 43, and a drive assembly 44. The hopper 41 is rotatably mounted on the top of the frame 1. The purpose of configuring the hopper 41 to be rotatable is to adjust the angle of the double helix soft-harvesting mechanism 4 relative to the ground so as to better harvest blueberries.

[0054] The guide hopper 42 is fixed on the top of the frame 1 and located behind the hopper 41. The screw shafts 43 are installed in pairs and rotate in parallel at the front inlet of the hopper 41. Several detachable soft fingers are distributed on the screw shafts 43, and a picking opening is formed between the two pairs of screw shafts 43.

[0055] Each pair of spiral shafts 43 is equipped with a drive assembly 44 as a power source to drive the two spiral shafts 43 to rotate synchronously in opposite directions. When the two spiral shafts 43 rotate synchronously inward, the soft fingers on the two spiral shafts 43 can simulate the picking action of a human hand, pushing the blueberry branches into the picking opening and removing the ripe blueberries from the branches. The harvested blueberries are sent into the collection frame 12 through the guide hopper 42. When the two spiral shafts 43 rotate synchronously outward, the soft fingers on the two spiral shafts 43 release the blueberry branches.

[0056] Specifically, the hopper 41 includes two opposing fan-shaped side plates 411 rotatably connected to the top of the frame 1. A top crossbeam 412 and a bottom plate 413 connect the two fan-shaped side plates 411. The front inlet of the hopper 41 is formed by the top crossbeam 412, the bottom plate 413, and the two fan-shaped side plates 411. The rear end of the bottom plate 413 extends into the guide hopper 42. After the hopper 41 is manually rotated, its angle is locked by tightening the rotating joint with a screw rod. This locking method is a conventional technology.

[0057] The drive assembly 44 is fixed below the base plate 413 and has two output ends with opposite directions of rotation. One end of each of the two helical shafts 43 is connected to the two output ends of the drive assembly 44, and the other end of each of the two helical shafts 43 is rotatably connected to the top crossbeam 412.

[0058] Combination Figure 7 The drive assembly 44 includes a second motor 441, a drive assembly housing, and a drive gear 442, a large intermediate gear 443, a small intermediate gear 444, a first driven gear 445, a transition gear 446, and a second driven gear 447 rotatably disposed inside the drive assembly housing. The large intermediate gear 443 and the small intermediate gear 444 are coaxially arranged. The large intermediate gear 443 meshes with both the drive gear 442 and the first driven gear 445. The transition gear 446 meshes with both the small intermediate gear 444 and the second driven gear 447 (the transition gear 446 is rotatably connected to one side of the drive assembly housing, and its shaft does not pass through the large intermediate gear 443). The upper end of the drive assembly housing has a V-shaped notch located between the first driven gear 445 and the second driven gear 447. The second motor 441 is fixed to the outside of the drive assembly housing, and its output end extends into the drive assembly housing and connects to the drive gear 442. Therefore, the second motor 441 can drive the first passive gear 445 and the second passive gear 447 to rotate in opposite directions.

[0059] One end of each of the two helical shafts 43 is detachably connected to the output shafts of the first driven gear 445 and the second driven gear 447, respectively. Specifically, one end of the helical shaft 43 has an inner tapered hole, and the corresponding end of the output shaft of the driven gear is designed with an outer tapered structure, and the two are fitted together.

[0060] The other ends of each of the two spiral shafts 43 are detachably rotatably connected to the top crossbeam 412. Specifically, the other end of the spiral shaft 43 is designed with a spherical structure. A first end plate 46 is bolted to the outside of the top crossbeam 412. A circular hole is opened in the center of the first end plate 46, and the spherical structure is embedded in the circular hole. Thus, the first end plate 46 can axially limit the other end of the spiral shaft 43, while the spiral shaft 43 can rotate. The spiral shaft 43, together with the soft finger attached thereto, can be quickly disassembled for easy cleaning of the equipment. Furthermore, the spiral shaft 43 and soft finger can be replaced entirely to suit different blueberry varieties.

[0061] In some embodiments, the distance between the two helical shafts 43 is adjustable. Specifically, in this embodiment, the right helical shaft 43 is designed to be movable. To this end, an arc-shaped groove 448 is provided on the drive assembly housing for the output shaft of the first driven gear 445 to slide. The arc-shaped groove 448 is centered on the center of the large intermediate gear 443, so that the first driven gear 445 can always mesh with the large intermediate gear 443 during its movement along the arc-shaped groove 448. To prevent the output shaft of the first driven gear 445 from sliding along the arc-shaped groove 448, a locating pin hole is designed at the other end of the output shaft of the first driven gear 445. The locating pin hole is hinged to a locating screw, which can be tightly connected to the drive assembly housing, thereby restricting the position of the first driven gear 445.

[0062] Correspondingly, such as Figure 9 and Figure 10 As shown, a second end plate 47 is provided on the outer side of the top crossbeam 412, and the second end plate 47 is connected to the top crossbeam 412 by bolts. An arc-shaped guide groove is provided on the end face of the second end plate 47. The spherical structure of the other end of the right-side spiral shaft 43 is embedded in the guide groove, thereby allowing the second end plate 47 to axially limit the other end of the spiral shaft 43, while allowing the spiral shaft 43 to rotate. Since the other end of the output shaft of the first driven gear 445 is provided with a positioning pin hole and a positioning screw, and the spiral shaft 43 is nearly vertically positioned, the other end of the spiral shaft 43 will not slide along the guide groove on the second end plate 47 during use. To ensure that the right-side spiral shaft 43 can move, an arc-shaped groove for the spiral shaft 43 to move is also provided on the top crossbeam 412. In this embodiment, the distance between the two spiral shafts 43 is adjustable, allowing the distance between the two spiral shafts 43 to be set according to the size of the fruit bundle, improving applicability under different working conditions.

[0063] Combination Figure 8The soft finger is a first soft finger 45, and several first soft fingers 45 are spirally distributed on the helical shaft 43. Each first soft finger 45 includes a root structure, an elastic body 451, and a spherical soft body 452 connected in sequence. The root structure is threaded to the helical shaft 43 or connected by a snap-fit. The elastic body 452 is a spring or other elastic structure. The spherical soft body 452 can be replaced with other spherical, elliptical, or other rounded structures. Furthermore, a rubber finger sleeve 453 is fitted onto the first soft finger 45, and a circular protrusion is provided on the root structure to secure the rubber finger sleeve 453. Because the first soft finger 45 is made of soft material and its structure is deformable, this first soft finger 45 results in an extremely low blueberry damage rate.

[0064] In practice, the elastomer 451 needs to be tested to determine the appropriate elasticity to ensure that ripe blueberries can be picked while preventing unripe berries from falling off. The detachable connection between the elastomer 451 and the spiral shaft 43 facilitates this testing and selection process. Due to its hygienic and soft characteristics, the rubber finger sleeve 453 can be customized according to actual picking needs to better protect the bloom on the blueberry surface and improve picking quality.

[0065] like Figure 11 and Figure 12 As shown, in some embodiments, the soft shifter uses a second soft shifter 48. Several second soft shifters 48 are spaced apart on the helical shaft 43, and the second soft shifters 48 on two helical shafts 43 are staggered. The second soft shifter 48 is designed as a centrally symmetrical teardrop handle structure, with a circular hole at its center that fits with the helical shaft 43 with a clearance fit. An internally threaded hole communicating with the circular hole is provided on the side of the circular hole, and a plunger 481 is threadedly connected to the internally threaded hole. The outer end of the plunger 481 has an internal hexagonal hole to facilitate rotation of the plunger 481. The inner end of the plunger 481 is hollow and equipped with a spring. A hemisphere is connected to the end of the spring, and the hemisphere contacts the circumferential surface of the helical shaft 43.

[0066] The spring force can be adjusted by rotating the plunger 481, thus changing the frictional resistance between the hemisphere and the helical shaft 43. Slippage occurs when the contact force between the teardrop handle structure and the object exceeds the frictional resistance between the teardrop handle structure and the helical shaft 43. Therefore, by adjusting the frictional resistance, the object being touched can be protected, allowing ripe blueberries to be picked while preventing unripe fruit from falling off. In practice, the frictional resistance also needs to be determined experimentally. The end connection of the teardrop handle structure is designed as a small-section, smooth transition section. This small-section, smooth transition section makes the end of the teardrop handle structure more elastic, providing better protection for the blueberries.

[0067] A V-shaped elastic pad 415 is provided on the front side of the hopper 41 at the position corresponding to the V-shaped notch of the drive assembly housing. The V-shaped elastic pad 415 serves to protect the blueberry branches. The harvested blueberries enter the hopper 41 and are collected into the collection frame 12 by the guide port at the bottom of the guide hopper 42.

[0068] In this embodiment, two pairs of spiral shafts 43 are configured and spaced apart on the hopper 41. A partition 414 is provided between the fan-shaped side plate 411 and the adjacent spiral shaft 43, and between the two pairs of spiral shafts 43. The partition 414 serves to guide the fruit bundles and to strengthen the structure.

[0069] (iv) Collect 5

[0070] like Figure 5 As shown, the collection bag 5 includes two parallel support rods 51, which are fixed to the frame 1. An elastic bag body 52 is provided between the two support rods 51, and an elastic line 53 is fixed to the front end of the elastic bag body 52. ​​After the elastic line 53 contacts the blueberry branch, it can deform around it, and the scattered blueberries are collected by the elastic bag body 52 and sent to the collection frame 12.

[0071] (V) Walking mechanism 7

[0072] like Figure 13 As shown, the walking mechanism 7 is mounted at the bottom of the frame 1 and has two front wheels 71 and two rear wheels 72, each with its own built-in drive motor. The two front wheels 71 are connected via a steering gear 73, as are the two rear wheels 72. The wheel frame includes a wheel seat plate, a wheel support arm 74, and a connecting rod 75. The wheel seat plate is rotatably engaged with the frame 1, and the wheel support arm 74 is engaged with the wheel seat plate via a shaft-hole connection. The wheel is mounted on the lower end of the wheel support arm 74. The connecting rod 75 includes a hexagonal sleeve with internal threads at both ends, and L-shaped rods are threaded to both ends. The other ends of the two L-shaped rods are rotatably connected to the wheel seat plate and the wheel support arm 74, respectively. Thus, the wheel seat plate, the wheel support arm 74, and the connecting rod 75 form a stable triangular structure. By rotating the hexagonal sleeve, the two L-shaped rods can be simultaneously extended or retracted from the hexagonal sleeve, thereby adjusting the length of the connecting rod 75 and thus adjusting the height of the frame 1. When moving forward, all four wheels move forward in parallel, and the front and rear wheels can be controlled independently. The same applies when moving backward. When lateral movement is required, the front and rear wheels turn simultaneously, driven by the built-in drive motor; when turning is required, the front and rear wheels turn in opposite directions.

[0073] The above describes a structural form of a walking mechanism 7 provided by an embodiment of the present invention. Of course, the walking mechanism 7 can also adopt forms such as Mecanum wheels or track wheels, depending on the specific application scenario.

[0074] The small, soft-bodied blueberry picking robot provided in this embodiment of the invention has its control process implemented based on existing algorithms:

[0075] (1) Path planning and obstacle avoidance

[0076] By processing the surrounding environment image through a path planning algorithm, the optimal driving path is obtained, and the robot identifies and avoids obstacles during its movement.

[0077] (2) Target blueberry branch identification and grasping

[0078] Basic YOLO models, such as YOLOv8 and YOLOv5, are used as the blueberry branch recognition model. The model is trained using a pre-prepared dataset of blueberry plant images. The model selects blueberry branches that meet a set maturity threshold (visual detection of blueberry maturity is an existing technology) as target blueberry branches. Real-time captured images of blueberry plants are input into the pre-trained model to identify the target blueberry branches.

[0079] The gripper assembly 35 is moved to the target blueberry branch by the robotic arm pose control algorithm to grab the fruit, and then sent to the double helix soft picking mechanism 4 for fruit picking.

Claims

1. A small soft blueberry picking robot, comprising a frame (1) and a walking mechanism (7), characterized in that, The frame (1) is equipped with a feeding robotic arm (3), a double helix soft picking mechanism (4) and a collection frame (12). The double-helix soft-harvesting mechanism (4) includes a hopper (41) and a guide hopper (42). At least one pair of spiral shafts (43) are rotatably arranged at the front inlet of the hopper (41). A harvesting opening is formed between the two pairs of spiral shafts (43). Each pair of spiral shafts (43) is equipped with a drive assembly (44). Several soft fingers are distributed on the spiral shafts (43). The soft fingers are configured to pick ripe blueberries and prevent unripe fruits from falling off. The feeding robotic arm (3) is used to grab blueberry branches and feed them into the double helix soft picking mechanism (4); the drive assembly (44) is used to drive the two helical shafts (43) to rotate inward synchronously, so that the soft fingers on the two helical shafts (43) can simulate the picking action of a human hand, push the blueberry branches into the picking mouth and remove the ripe blueberries from the blueberry branches; or drive the two helical shafts (43) to rotate outward synchronously, so that the soft fingers on the two helical shafts (43) release the blueberry branches; the guide hopper (42) is used to collect the picked blueberries from the hopper (41) into the collection frame (12); The soft shifter uses a first soft shifter (45), and several first soft shifters (45) are spirally distributed on the spiral shaft (43); the first soft shifter (45) includes a root structure, an elastomer (451) and a spherical soft body (452) connected in sequence, and the root structure is detachably connected to the spiral shaft (43); a rubber finger sleeve (453) is fitted on the first soft shifter (45), and a circular protrusion structure for fixing the rubber finger sleeve (453) is provided on the root structure; the elastic force of the first soft shifter (45) is determined by test; Alternatively, the soft finger is a second soft finger (48), and several second soft fingers (48) are spaced apart on the helical shaft (43), and the second soft fingers (48) on the two helical shafts (43) are staggered; the second soft finger (48) is a centrally symmetrical teardrop handle structure, with a circular hole in the center that is clearance-fitted with the helical shaft (43), and an internal threaded hole communicating with the circular hole on the side of the circular hole, with a plunger (481) threaded in the internal threaded hole, and an internal hexagonal hole at the outer end of the plunger (481) to facilitate the rotation of the plunger (481); the inner end of the plunger (481) is a hollow structure and is equipped with a spring, with a hemisphere connected to the end of the spring, which contacts the circumferential surface of the helical shaft (43); the frictional resistance between the teardrop handle structure and the helical shaft (43) is determined by rotating the plunger (481) and by experiment; the end connection of the teardrop handle structure has a smooth transition section with a small cross section.

2. The small soft blueberry picking robot according to claim 1, characterized in that, The hopper (41) includes two fan-shaped side plates (411) that are arranged opposite to each other and rotatably connected to the top of the frame (1). A top crossbeam (412) and a bottom plate (413) are connected between the two fan-shaped side plates (411). The front entrance of the hopper (41) is formed by the top crossbeam (412), the bottom plate (413) and the two fan-shaped side plates (411). The rear end of the bottom plate (413) extends into the guide hopper (42).

3. The small soft-bodied blueberry picking robot according to claim 2, characterized in that, The drive assembly (44) is fixed below the base plate (413) and has two output ends with opposite directions of rotation; one end of each of the two helical shafts (43) is connected to the two output ends of the drive assembly (44), and the other end of each of the two helical shafts (43) is detachably rotatably connected to the top crossbeam (412).

4. The small soft blueberry picking robot according to claim 3, characterized in that, The drive assembly (44) includes a second motor (441), a drive assembly housing, and a drive gear (442), a large intermediate gear (443), a small intermediate gear (444), a first driven gear (445), a transition gear (446), and a second driven gear (447) rotatably disposed inside the drive assembly housing. The large intermediate gear (443) and the small intermediate gear (444) are coaxially arranged. The large intermediate gear (443) meshes with the drive gear (442) and the first driven gear (445) respectively. The transition gear (446) meshes with the small intermediate gear (444) and the second driven gear (447) respectively. The second motor (441) is fixed on the outside of the drive assembly housing. The output end of the second motor (441) extends into the drive assembly housing and is connected to the drive gear (442). One end of each of the two helical shafts (43) is detachably connected to the output shafts of the first driven gear (445) and the second driven gear (447) respectively.

5. The small soft-bodied blueberry picking robot according to claim 4, characterized in that, The spiral shaft (43) connected to the output shaft of the first driven gear (445) is configured to be movable, thereby adjusting the distance between the two spiral shafts (43); an arc-shaped groove (448) for sliding the output shaft of the first driven gear (445) is provided on the drive assembly housing, with the center of the large intermediate gear (443) as the center; a positioning pin hole is provided at the other end of the output shaft of the first driven gear (445), which is hinged to the positioning screw, and the positioning screw is tightly connected to the drive assembly housing to limit the position of the first driven gear (445); a second end plate (47) is provided on the outer side of the top crossbeam (412), and an arc-shaped guide groove is opened on the end face of the second end plate (47). The ball-shaped structure part of the other end of the spiral shaft (43) is embedded in the guide groove, and the second end plate (47) axially limits the other end of the spiral shaft (43), while the spiral shaft (43) can rotate; an arc-shaped groove for the spiral shaft (43) to move is also opened on the top crossbeam (412).

6. The small soft blueberry picking robot according to claim 1, characterized in that, The double-helix soft picking mechanism (4) has linear modules (2) on both sides, and the feeding robot arm (3) is set on the linear module (2). The linear module (2) is used to adjust the height of the feeding robot arm (3) to adapt to blueberry plants of different heights.

7. The small soft blueberry picking robot according to claim 1, characterized in that, The gripper assembly (35) at the end of the feeding robotic arm (3) has two openable gripper bodies (351), the surface of which is made of soft material; protrusions (353) and grooves (354) are alternately arranged on the opposite sides of the two gripper bodies (351) from the outside to the inside, and the size of the grooves (354) gradually decreases from the outside to the inside in order to adapt to the gripping of blueberry branches of different diameters; the opposite ends of the two gripper bodies (351) are connected by a sheet-like soft strap (352), which, together with the two gripper bodies (351), can adaptively wrap the blueberry branches.

8. The small soft-bodied blueberry picking robot according to any one of claims 1 to 7, characterized in that, A collection bag (5) is inclined below the double helix soft picking mechanism (4). One end of the collection bag (5) extends to the front of the double helix soft picking mechanism (4) and tilts upward, while the other end extends to the collection frame (12) to collect scattered blueberries.

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