Flexible multi-joint picking manipulator and picking method thereof

Abstract

The invention provides a flexible multi-joint picking manipulator and a picking method thereof, which are used for solving the technical problems of low picking efficiency, high energy consumption, relatively single picking type and easiness in causing damage to fruits and vegetables due to the fact that the existing picking manipulator needs to increase drive for each degree of freedom in the picking process and the control process is relatively complicated. According to the flexible multi-joint picking manipulator, the single-joint thumb and the two multi-joint main fingers are matched to clamp fruits and vegetables to be picked, the three-point clamping mode is better in stability, the two multi-joint main fingers are arranged in a linkage mode, so that the motion trails are the same, and the motion rigidity and clamping synchronism are improved; meanwhile, the flexible knuckles of the multi-joint main finger achieve deformation of finger pulps through torsional deformation of the flexible connecting structures, so that the finger pulps can generate corresponding deformation according to irregular shapes of fruits and vegetables when the fruits and the vegetables are picked, the fruits and the vegetables to be picked are adaptively clamped, and damage to the fruits and the vegetables in the picking process is effectively avoided.

Description

Technical Field

[0001] This invention relates to a harvesting robot, specifically to a flexible multi-joint harvesting robot and its harvesting method. Background Technology

[0002] A robotic arm is the end effector of a robotic arm, also known as a robotic gripper, which is equivalent to a human hand and can perform various operations. With the improvement of living standards and the development of the agricultural economy, the demand and output of fruits and vegetables have increased dramatically. However, the labor and time-consuming nature of manual harvesting have become a significant burden, leading to an increase in the proportion of fruit and vegetable harvesting costs in the price of fruits and vegetables. Using harvesting robotic arms can greatly improve production efficiency and reduce harvesting costs.

[0003] Existing harvesting robots mainly consist of several parts, including a gripping mechanism, a cutting mechanism, and an adsorption mechanism. Currently, the structural forms of harvesting robots mainly include the following four types: 1. Robots that grasp and harvest using a fulcrum as the center; 2. Parallel-grip harvesting robots with both sides; 3. Multi-finger harvesting robots; 4. Shape memory alloy harvesting robots. These types of harvesting robots require additional actuation for each degree of freedom during the harvesting process, making the control process relatively complex, resulting in low harvesting efficiency and high energy consumption. Furthermore, existing harvesting robots are limited in their ability to harvest a single type of fruit and vegetable and are prone to damaging fruits and vegetables during harvesting. The gripping process mainly relies on adding soft pads to the fingers to protect the fruits and vegetables, but these soft pads have relatively small deformation capacity, making them less adaptable to irregularly shaped fruits and vegetables. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of existing harvesting robots, which require additional drive for each degree of freedom during the harvesting process, resulting in relatively complex control processes, low harvesting efficiency, high energy consumption, limited harvesting variety, and easy damage to fruits and vegetables. The invention provides a flexible multi-joint harvesting robot and its harvesting method.

[0005] To achieve the above objectives, the technical solution provided by the present invention is as follows: A flexible multi-joint harvesting robot is characterized by including a mounting base, a single-joint thumb, two multi-joint main fingers, a cutting mechanism, and a drive mechanism. The two multi-joint main fingers have the same structure, each including three flexible phalanges; each flexible phalange includes a first connecting end, a second connecting end, and a flexible fingertip connecting the first connecting end and the second connecting end; the flexible fingertip includes a fingertip base, a fingertip column vertically connected to one side of the fingertip base at its lower end, a flexible connecting structure vertically connected to the inner side of the upper end of the fingertip column at one end, and a fingertip horizontally connected to the other end of the flexible connecting structure; a limiting block protruding upward is provided at the middle of the upper surface of the fingertip base; the inner side of the single-joint thumb and the fingertips of the three flexible phalanges of the multi-joint main fingers are used to contact the fruits and vegetables to be picked; The lower end of the single-joint thumb and the first connecting end of the lowermost flexible phalanx of the multi-joint main finger are respectively connected to the mounting base by a spiral spring; the second connecting end of the lowermost flexible phalanx of the multi-joint main finger is rotatably connected to the first connecting end of the middle flexible phalanx, and the second connecting end of the middle flexible phalanx is rotatably connected to the first connecting end of the uppermost flexible phalanx; the two multi-joint main fingers are symmetrical about the center line connecting the single-joint thumb and the mounting base, and are linked together. The driving mechanism includes two first driving motors and a second driving motor; the two first driving motors are respectively installed on the lowermost flexible phalanx and the middle flexible phalanx of any multi-joint master finger, and are used to drive the middle flexible phalanx and the uppermost flexible phalanx of the corresponding multi-joint master finger to rotate. The cutting mechanism and the second drive motor are respectively installed on the uppermost flexible phalanx of the multi-joint main finger. The second drive motor is used to drive the cutting mechanism to cut the roots of the fruits and vegetables to be harvested.

[0006] Furthermore, the upper surface of the mounting base is provided with three sets of fixing seats along the circumferential direction. Each set of fixing seats includes two oppositely arranged plate-shaped columns. The outer sides of the two plate-shaped columns in each set are respectively connected to a spiral spring, and the outer end of the spiral spring is connected to the corresponding plate-shaped column. A through hole is opened on each plate-shaped column at the position corresponding to the inner end of the spiral spring. Rotating shafts are provided on both sides of the lower end of the single-joint thumb and on both sides of the first connecting end of the lowest flexible phalanx of the multi-joint main finger; each rotating shaft passes through the through hole of each plate-shaped column in the three sets of fixing seats and is connected to the inner end of the corresponding spiral spring.

[0007] Furthermore, it also includes a spiral spring adjusting block; The outer end of the vortex spring is connected to the vortex spring adjustment block, and the position of the vortex spring adjustment block can be adjusted horizontally on the plate-shaped column.

[0008] Furthermore, the upper surface of the flexible connection structure is provided with a groove extending along its length, and the two sides of the groove opening are flush with the fingertip column and the fingertip, respectively. Alternatively, the flexible connection structure may be a thin sheet extending along the length of the fingertip, and its thickness may be less than 1 / 5 of the thickness of the fingertip.

[0009] Furthermore, the first connecting end, the second connecting end, the fingertip base, the fingertip column, the flexible connecting structure, and the fingertip are an integrated structure.

[0010] Furthermore, an integrated connecting seat is provided between the uppermost flexible phalanges of the two multi-joint master fingers to realize the linkage between the two multi-joint master fingers; The cutting mechanism and the second drive motor are respectively mounted on the connecting base.

[0011] Furthermore, a flexible pad is provided on the inner surface of the single-joint thumb; The fingertip surface of each flexible phalanx of the multi-jointed master finger is provided with a flexible pad and a pressure sensor.

[0012] Furthermore, a connecting through hole is provided on the second connecting end of the lowest flexible phalanx of the multi-joint main finger, and a groove-type receiving cavity is provided on the first connecting end of the middle flexible phalanx. A drive connecting shaft is provided in the groove-type receiving cavity. The connecting through hole of the second connecting end of the lowest flexible phalanx and the drive connecting shaft of the first connecting end of the middle flexible phalanx cooperate to achieve a rotational connection. A connecting through hole is provided on the second connecting end of the middle flexible phalanx of the multi-joint main finger, and a driving connecting shaft is provided on the outer side of the first connecting end of the uppermost flexible phalanx. The connecting through hole of the second connecting end of the middle flexible phalanx and the driving connecting shaft of the first connecting end of the uppermost flexible phalanx cooperate to achieve a rotational connection. The two first drive motors are respectively located on the upper part of the lowermost flexible phalanx and the upper part of the middle flexible phalanx of any multi-joint master finger. Their drive ends are respectively connected to the drive connecting shafts of the first connecting ends of the middle flexible phalanx and the uppermost flexible phalanx, and are used to drive the corresponding drive connecting shafts to rotate, thereby driving the corresponding flexible phalanx to move.

[0013] In addition, the present invention also provides a harvesting method for the above-mentioned flexible multi-joint harvesting robot, which is characterized by including the following steps: Step 1: The flexible multi-joint picking robot selects the fruits and vegetables to be picked. The spiral spring deforms under the push of the size and weight of the fruits and vegetables to be picked, thereby changing the angle of the lowest flexible joint of the single-joint thumb and the multi-joint main finger, so as to adaptively clamp the fruits and vegetables to be picked. Step 2: The two first drive motors drive the middle flexible phalanx and the uppermost flexible phalanx of the multi-joint main finger respectively to assist the lowermost flexible phalanx in clamping the fruits and vegetables to be picked. Step 3: Harvest the fruits and vegetables to be picked.

[0014] Furthermore, in step 1, the flexible multi-joint picking robot is also equipped with a spiral spring adjustment block; By adjusting the vortex spring adjusting block, the position of the outer end of the vortex spring relative to the plate-shaped column is changed, thereby changing the angle range between the single-joint thumb and the lowest flexible phalanges of the two multi-joint main fingers, so as to adapt to the shape and size of the fruits and vegetables to be picked. In step 3, if the fruits and vegetables to be harvested are hard, clamping force is used to harvest them; if they are soft, the root of the fruits and vegetables to be harvested is cut by a cutting mechanism.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a flexible multi-joint harvesting robot that uses a single-joint thumb and two multi-joint main fingers to grip fruits and vegetables to be harvested. This three-point clamping method not only provides better stability, but the two multi-joint main fingers are linked to ensure that their movement trajectories are the same, improving motion rigidity and gripping synchronization. At the same time, the flexible joints of the multi-joint main fingers deform through the torsional deformation of the flexible connection structure, allowing the fingertips to deform accordingly according to the irregular shape of the fruits and vegetables during harvesting. This adaptively grips the fruits and vegetables, effectively avoiding damage during harvesting, ensuring the quality of the fruits and vegetables, and providing a more efficient harvesting technology for spherical fruits of different types and sizes.

[0016] 2. The present invention provides a flexible multi-joint harvesting robot, in which the single-joint thumb and the lowermost flexible phalanges of the multi-joint main fingers are connected by a spiral spring. During fruit and vegetable harvesting, the spiral spring deforms under the push of the size and weight of the fruit and vegetables to be harvested, thereby changing the angle of the single-joint thumb and the lowermost flexible phalanges of the multi-joint main fingers, realizing adaptive gripping of fruits and vegetables of different sizes, effectively reducing the number of drive motors, not only reducing energy consumption, but also reducing drive complexity and increasing the reliability of the harvesting robot.

[0017] 3. The present invention provides a flexible multi-joint harvesting robot with a three-joint design of the multi-joint main finger. This design allows the single-joint thumb and two multi-joint main fingers to work together to clamp the fruits and vegetables to be harvested. Not only can the angle of the uppermost flexible joint of the multi-joint main finger be adjusted to achieve harvesting, but the cutting mechanism can also be used to cut the fruit and vegetables, further improving the harvesting efficiency of the harvesting robot.

[0018] 4. The flexible multi-joint harvesting robot provided by the present invention is provided with a spiral spring adjustment block on the plate-shaped column, and the outer end of the spiral spring is connected to the spiral spring adjustment block. When the size of the harvested fruits and vegetables varies too much or when it is necessary to harvest fruits and vegetables with different structural sizes, the position of the outer end of the spiral spring relative to the plate-shaped column can be changed by adjusting the spiral spring adjustment block, thereby changing the angle range between the single-joint thumb and the lowermost flexible joints of the two multi-joint main fingers, so as to adapt to the shape and size of the fruits and vegetables to be harvested.

[0019] 5. The harvesting method of the flexible multi-joint harvesting robot provided by the present invention is simple and convenient. It not only enables adaptive clamping of the fruits and vegetables to be harvested, avoiding damage during harvesting, but also reduces energy consumption and drive complexity, effectively improving harvesting efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an embodiment of a flexible multi-joint harvesting robot according to the present invention; Figure 2 This is a three-dimensional structural diagram of each flexible phalanx in an embodiment of the present invention; Figure 3 This is a partial schematic diagram of each flexible phalanx in an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the connection between the single-joint thumb and the mounting base via a spiral spring in an embodiment of the present invention. Figure 5 This is a schematic diagram of harvesting according to an embodiment of the present invention.

[0021] The attached figures are labeled as follows: 1- Mounting base; 2- Single-joint thumb; 3- Multi-joint main finger; 31- Connecting base; 4- Cutting mechanism; 5- Sheet-shaped column; 6- Vortex spring; 7- Vortex spring adjusting block; 8- Fruits and vegetables to be harvested; 11-First connecting end; 12-Second connecting end; 13-Flexible fingertip; 131-Fingert base; 132-Fingert column; 133-Flexible connecting structure; 134-Fingert; 135-Limiting block. Detailed Implementation

[0022] To make the advantages and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1 As shown, a flexible multi-joint harvesting robot includes a mounting base 1, a single-joint thumb 2, two multi-joint main fingers 3, a cutting mechanism 4, a spiral spring adjusting block 7, two first drive motors, and a second drive motor. The mounting base 1 serves as the fixing point for the single-joint thumb 2 and the multi-joint main fingers 3.

[0024] The two multi-joint main fingers 3 have identical structures, and each multi-joint main finger 3 includes three flexible phalanges connected in sequence. In this invention, the two multi-joint main fingers 3 are symmetrical about the center line connecting the single-joint thumb 2 and the mounting base 1, and are linked together. Specifically, an integrated connecting base 31 is provided between the uppermost flexible phalanges of the two multi-joint main fingers 3 to realize the linkage between them.

[0025] like Figure 2 , Figure 3 As shown, the flexible knuckle includes a first connecting end 11, a second connecting end 12, and a flexible fingertip 13 integrally connected between the first connecting end 11 and the second connecting end 12. Specifically, the flexible fingertip 13 includes a fingertip base 131, a fingertip column 132 vertically and integrally connected to one side of the fingertip base 131 at its lower end, a flexible connecting structure 133 vertically and integrally connected to the inner side of the upper end of the fingertip column 132 at one end, and a fingertip 134 horizontally and integrally connected to the other end of the flexible connecting structure 133. The fingertips 134 of the three flexible knuckles—the inner side of the single-joint thumb 2 and the multi-joint main finger 3—are used to contact the fruits and vegetables 8 to be picked.

[0026] In this invention, the fingertip 134 becomes flexible through the deformation of the flexible connecting structure 133, allowing the fingertip 134 to deform relative to the fingertip base 131. The flexible connecting structure 333 is a rigid shaft without bearings and relatively weak in rigidity compared to the fingertip 134. During design, the shape and structure of the flexible connecting structure 133 need to be designed according to the materials used to adapt to fruits and vegetables of varying hardness. Preferably, in this invention, a groove extending along the length direction can be provided on the upper surface of the flexible connecting structure 133, with the two sides of the groove opening flush with the fingertip column 132 and the fingertip 134, respectively. Alternatively, the flexible connecting structure 133 can be designed as a thin sheet extending along the length direction of the fingertip 134, with a thickness less than 1 / 5 of the thickness of the fingertip 134, such as a diving board. In this embodiment, it is designed as a groove.

[0027] In addition, a protruding limiting block 135 is provided at the middle of the upper surface of the fingertip base 131. On the one hand, it is used to prevent the flexible connection structure 133 from deforming too much and affecting its service life. On the other hand, it increases the rigidity of the flexible finger joint and prevents the flexible finger joint from being damaged due to excessive deformation.

[0028] The design strength of the flexible connection structure 133 is calculated and verified using the following formula: ; ; ; in, Δ is the maximum rotation angle of the outer side of the fingertip 134 relative to the flexible connection structure 133, Δ is the gap between the limiting block 135 and the fingertip 134, and b is the width of the fingertip 134. Where σb is the design strength of the flexible connection structure 133, G is the flexural modulus of the material, W is the section modulus of the flexible connection structure 133, [σb] is the flexural strength of the material, and 1.2 is the reserved design margin.

[0029] The upper surface of the mounting base 1 is provided with three sets of fixing seats along the circumference, which are used to connect the lower end of the single-joint thumb 2 and the lowermost flexible phalanges of the two multi-joint main fingers 3 respectively. The three sets of fixing seats are located on the same circumference. The fixing seat connecting the single-joint thumb 2 is referred to as the first fixing seat, and the fixing seats connecting the lowermost flexible phalanges of the two multi-joint main fingers 3 are referred to as the second fixing seats. Preferably, the distance between the two sets of second fixing seats is greater than the distance between the second fixing seat and the first fixing seat.

[0030] like Figure 4 As shown, taking the single-joint thumb 2 as an example, the fixing base includes two oppositely arranged plate-shaped columns 5. A spiral spring 6 is connected to the outer side of each of the two plate-shaped columns 5, and a through hole is provided on each plate-shaped column 5 corresponding to the inner end of the spiral spring 6. The outer end of the spiral spring 6 is connected to a spiral spring adjusting block 7, and the position of the spiral spring adjusting block 7 can be adjusted horizontally on the plate-shaped columns 5. Rotating shafts are respectively provided on both sides of the lower end of the single-joint thumb 2 and on both sides of the first connecting end 11 of the lowest flexible phalanx of the multi-joint main finger 3. Each rotating shaft passes through the through hole of each plate-shaped column 5 in the three sets of fixing bases and connects to the inner end of the corresponding spiral spring 6. In this invention, the lower end of the single-joint thumb 2 and the lowermost flexible phalanx of the multi-joint main finger 3 are connected by a spiral spring 6. When the harvesting robot is harvesting fruits and vegetables, the spiral spring 6 deforms under the push of the size and weight of the fruits and vegetables to be harvested 8, thereby changing the angle of the lowermost flexible phalanx of the single-joint thumb 2 and the multi-joint main finger 3, realizing adaptive clamping of fruits and vegetables of different sizes, effectively reducing the number of drive motors and reducing energy consumption.

[0031] When the size of the harvested fruits and vegetables varies too much, or when it is necessary to harvest fruits and vegetables of a different structural size, the position of the outer end of the vortex spring 6 relative to the plate-shaped column 5 can be changed by adjusting the vortex spring adjusting block 7. This changes the angle range between the single-joint thumb 2 and the lowermost flexible joints of the two multi-joint main fingers 3, so that it can adapt to the shape and size of the fruits and vegetables 8 to be harvested.

[0032] Specifically, the second connecting end 12 of the lowest flexible phalanx of the multi-jointed main finger 3 has a connecting through hole, and the first connecting end 11 of the middle flexible phalanx has a groove-type receiving cavity. A drive connecting shaft is installed inside the groove-type receiving cavity. The connecting through hole of the second connecting end 12 of the lowest flexible phalanx and the drive connecting shaft of the first connecting end 11 of the middle flexible phalanx cooperate to achieve a rotatable connection. The second connecting end 12 of the middle flexible phalanx of the multi-jointed main finger 3 has a connecting through hole, and the outer side of the first connecting end 11 of the uppermost flexible phalanx is provided with a drive connecting shaft. The connecting through hole of the second connecting end 12 of the middle flexible phalanx and the drive connecting shaft of the first connecting end 11 of the uppermost flexible phalanx cooperate to achieve a rotatable connection. The middle and uppermost flexible phalanxes of the multi-jointed main finger 3 assist the lowest flexible phalanx in clamping the fruits and vegetables 8 to be harvested.

[0033] Because the two multi-joint master fingers 3 are linked together, the two first drive mechanisms only need to be installed on the lowermost flexible phalanx and the middle flexible phalanx of any one of the multi-joint master fingers 3 to achieve synchronous drive of the two multi-joint master fingers 3. This not only reduces the number of drive motors and lowers the drive cost, but also makes the control more efficient and reliable. The first drive motor can be a torque motor or a torque motor with a reducer. Types of reducers include planetary reducers, harmonic reducers, worm gear reducers, etc. During the design, a suitable reducer is selected to adjust the reduction ratio. During use, the drive torque can be adjusted by increasing or decreasing the motor current or voltage. In this embodiment, one first drive motor is located on the upper part of the lowermost flexible phalanx of the left multi-joint master finger 3, and its drive end is connected to the drive connecting shaft of the corresponding middle flexible phalanx. The other first drive motor is located on the upper part of the middle flexible phalanx of the left multi-joint master finger 3, and its drive end is connected to the drive connecting shaft of the corresponding uppermost flexible phalanx. It is used to drive the corresponding drive connecting shaft to rotate, thereby driving the movement of the corresponding flexible phalanx.

[0034] This invention uses a single-joint thumb 2 and two multi-joint main fingers 3 to grip the fruits and vegetables 8 to be harvested. Simultaneously, the flexible joints of the thumb 2 and the main fingers 3 rotate their fingertips 134 through the torsional elastic deformation of the flexible connecting structure 133, thus adaptively gripping the fruits and vegetables 8. This three-point gripping harvesting robot not only offers better stability but also, combined with the design of the flexible joints, allows it to deform accordingly to the irregular shapes of the fruits and vegetables during harvesting, avoiding damage and ensuring the quality of the produce. Figure 5As shown, for hard fruits and vegetables, after the single-joint thumb 2 and two multi-joint main fingers 3 work together to clamp the fruit or vegetable 8 to be picked, the angle of the uppermost flexible joint of the multi-joint main fingers is adjusted to achieve picking. For slightly softer fruits and vegetables, after the single-joint thumb 2 and two multi-joint main fingers 3 work together to clamp the fruit or vegetable 8 to be picked, the root of the fruit or vegetable 8 to be picked is cut by the cutting mechanism 4. The cutting mechanism 4 and the second drive motor are respectively set on the connecting seat 31 between the two multi-joint main fingers 3. After the single-joint thumb 2 and two multi-joint main fingers 3 work together to clamp the fruit or vegetable 8 to be picked, the second drive motor drives the cutting mechanism 4 to cut the root of the fruit or vegetable 8 to be picked. The second drive motor can also be a torque motor or a torque motor with a reducer. The torque motor needs to have a fast response and large torque. If the root of the fruit or vegetable is not cut in one go, it can be repeatedly cut by the program to ensure cutting efficiency. In this embodiment, the cutting mechanism 4 is a cutting blade. The cutting blade can rotate 360 ​​degrees and return to the initial position after one picking.

[0035] Preferably, flexible pads, such as rubber or polyimide, are provided on the inner surface of the single-joint thumb 2 and the fingertip 134 of each flexible phalanx of the multi-joint main finger 3. These pads further increase the flexibility and deformability of the single-joint thumb 2 or fingertip 134, improving the adaptability to different sizes of fruits and vegetables and protecting them from damage. A pressure sensor is also provided on the fingertip 134, which can more clearly indicate whether the grip is tight during harvesting. Furthermore, even if the pressure sensor deviates, the invention can ensure the integrity of the harvested fruits and vegetables and prevent damage under the action of the spiral spring 6 at the bottom of the harvesting robot.

[0036] The harvesting method of the flexible multi-joint harvesting robot of the present invention is as follows: Step 1: The flexible multi-joint harvesting robot selects the fruit and vegetable to be harvested 8. The spiral spring 6 deforms under the size and weight of the fruit and vegetable to be harvested 8, thereby changing the angle between the single-joint thumb 2 and the lowermost flexible phalanx of the multi-joint main finger 3, so as to realize the adaptive clamping of fruits and vegetables of different sizes.

[0037] Since this embodiment also includes a vortex spring adjustment block 7, when the size of the fruit and vegetable to be harvested 8 changes too much or when it is necessary to harvest another type of fruit and vegetable with a different structural size, the vortex spring adjustment block 7 can be adjusted to change the position of the outer end of the vortex spring 6 relative to the sheet-like column 5, thereby changing the angle range between the single-joint thumb 2 and the lowermost flexible phalanges of the two multi-joint main fingers 3, so that it can adapt to the shape and size of the fruit and vegetable to be harvested 8.

[0038] Step 2: After the single-joint thumb 2 and the lowermost flexible phalanx of the multi-joint main finger 3 hold the fruit and vegetable 8 to be picked, the two first drive motors drive the middle flexible phalanx and the uppermost flexible phalanx of the multi-joint main finger 3 respectively to assist the lowermost flexible phalanx in clamping the fruit and vegetable 8 to be picked.

[0039] Step 3: After clamping the fruit or vegetable 8 to be picked using a single-joint thumb and two multi-joint main fingers, if the fruit or vegetable 8 to be picked is a hard fruit or vegetable, the picking is achieved by adjusting the angle of the uppermost flexible joint of the multi-joint main fingers. If it is a soft fruit or vegetable, the root of the fruit or vegetable 8 to be picked is cut and picked by the cutting mechanism 4.

[0040] During the harvesting process, the fingertips 134 of each flexible phalanx of the multi-jointed main finger 3 are flexible through the deformation of the corresponding flexible connection structure 133, which effectively avoids damage to fruits and vegetables during harvesting and ensures the quality of fruits and vegetables.

[0041] The above description is only used to illustrate the technical solutions of the present invention, and is not intended to limit them. For those skilled in the art, modifications can be made to the specific technical solutions described in the above embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A flexible multi-joint harvesting robot, characterized in that: It includes a mounting base (1), a single-joint thumb (2), two multi-joint main fingers (3), a cutting mechanism (4), and a drive mechanism; The two multi-joint main fingers (3) have the same structure and each includes three flexible phalanges. Each flexible phalange includes a first connecting end (11), a second connecting end (12), and a flexible fingertip (13) connecting the first connecting end (11) and the second connecting end (12). The flexible fingertip (13) includes a fingertip base (131), a fingertip column (132) vertically connected to one side of the fingertip base (131), a flexible connecting structure (133) vertically connected to the inner side of the upper end of the fingertip column (132), and a fingertip (134) horizontally connected to the other end of the flexible connecting structure (133). A limiting block (135) protruding upward is provided at the middle of the upper surface of the fingertip base (131). The inner side of the single-joint thumb (2) and the fingertip (134) of the three flexible phalanges of the multi-joint main fingers (3) are used to contact the fruits and vegetables (8) to be picked. The lower end of the single-joint thumb (2) and the first connecting end (11) of the lowermost flexible phalanx of the multi-joint main finger (3) are respectively connected to the mounting base (1) by a spiral spring (6); the second connecting end (12) of the lowermost flexible phalanx of the multi-joint main finger (3) is rotatably connected to the first connecting end (11) of the middle flexible phalanx, and the second connecting end (12) of the middle flexible phalanx is rotatably connected to the first connecting end (11) of the uppermost flexible phalanx; the two multi-joint main fingers (3) are symmetrical about the center line connecting the single-joint thumb (2) and the mounting base (1), and are linked together; The driving mechanism includes two first driving motors and a second driving motor; the two first driving motors are respectively set on the lowermost flexible phalanx and the middle flexible phalanx of any multi-joint master finger (3), and are used to drive the middle flexible phalanx and the uppermost flexible phalanx of the corresponding multi-joint master finger (3) to rotate respectively; The cutting mechanism (4) and the second drive motor are respectively set on the uppermost flexible phalanx of the multi-joint main finger (3). The second drive motor is used to drive the cutting mechanism (4) to cut the roots of the fruits and vegetables (8) to be harvested.

2. The flexible multi-joint harvesting robot according to claim 1, characterized in that: The mounting base (1) has three sets of fixing seats arranged circumferentially on its upper surface. Each set of fixing seats includes two oppositely arranged plate-shaped columns (5). The outer sides of the two plate-shaped columns (5) in each set are respectively connected to a spiral spring (6), and the outer end of the spiral spring (6) is connected to the corresponding plate-shaped column (5). A through hole is opened on each plate-shaped column (5) at the position corresponding to the inner end of the spiral spring (6). Rotating shafts are provided on both sides of the lower end of the single-joint thumb (2) and on both sides of the first connecting end (11) of the lowest flexible phalanx of the multi-joint main finger (3); each rotating shaft passes through the through hole of each plate-shaped column (5) in the three sets of fixed seats and is connected to the inner end of the corresponding spiral spring (6).

3. The flexible multi-joint harvesting robot according to claim 1 or 2, characterized in that: It also includes a spiral spring adjusting block (7); The outer end of the vortex spring (6) is connected to the vortex spring adjustment block (7), and the position of the vortex spring adjustment block (7) can be adjusted horizontally on the plate column (5).

4. The flexible multi-joint harvesting robot according to claim 3, characterized in that: The upper surface of the flexible connection structure (133) is provided with a groove extending along its length, and the two sides of the groove opening are flush with the fingertip column (132) and the fingertip (134) respectively. Alternatively, the flexible connection structure (133) is a sheet-like structure extending along the length of the fingertip (134), and its thickness is less than 1 / 5 of the thickness of the fingertip (134).

5. The flexible multi-joint harvesting robot according to claim 4, characterized in that: The first connecting end (11), the second connecting end (12), the fingertip base (131), the fingertip column (132), the flexible connecting structure (133), and the fingertip (134) are an integrated structure.

6. The flexible multi-joint harvesting robot according to claim 5, characterized in that: An integrated connecting seat (31) is provided between the uppermost flexible phalanges of the two multi-joint main fingers (3) to realize the linkage between the two multi-joint main fingers (3); The cutting mechanism (4) and the second drive motor are respectively mounted on the connecting seat (31).

7. The flexible multi-joint harvesting robot according to claim 6, characterized in that: A flexible pad is provided on the inner surface of the single-joint thumb (2); The surface of the fingertip (134) of each flexible phalanx of the multi-joint master finger (3) is provided with a flexible pad and a pressure sensor.

8. The flexible multi-joint harvesting robot according to claim 7, characterized in that: The lowermost flexible phalanx of the multi-joint main finger (3) has a connecting through hole on the second connecting end (12), and the middle flexible phalanx has a groove-type receiving cavity. A drive connecting shaft is provided in the groove-type receiving cavity. The connecting through hole of the lowermost flexible phalanx second connecting end (12) and the drive connecting shaft of the middle flexible phalanx first connecting end (11) cooperate to achieve a rotational connection. The second connecting end (12) of the middle flexible phalanx of the multi-joint main finger (3) is provided with a connecting through hole, and a driving connecting shaft is provided on the outside of the first connecting end (11) of the uppermost flexible phalanx. The connecting through hole of the second connecting end (12) of the middle flexible phalanx and the driving connecting shaft of the first connecting end (11) of the uppermost flexible phalanx cooperate to achieve a rotational connection. The two first drive motors are respectively located on the upper part of the lowermost flexible phalanx and the upper part of the middle flexible phalanx of any multi-joint master finger (3). Their drive ends are respectively connected to the drive connecting shafts of the first connecting ends (11) of the middle flexible phalanx and the uppermost flexible phalanx, and are used to drive the corresponding drive connecting shafts to rotate, thereby driving the corresponding flexible phalanx to move.

9. A harvesting method using a flexible multi-joint harvesting robot as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: The flexible multi-joint picking robot selects the fruit and vegetable to be picked (8). The spiral spring (6) deforms under the size and weight of the fruit and vegetable to be picked (8), thereby changing the angle of the lowest flexible joint of the single joint thumb (2) and the multi-joint main finger (3) to adaptively clamp the fruit and vegetable to be picked (8). Step 2: The two first drive motors drive the middle flexible phalanx and the uppermost flexible phalanx of the multi-joint master finger (3) respectively, so as to assist the lowermost flexible phalanx in clamping the fruits and vegetables to be picked (8). Step 3: Harvest the fruits and vegetables (8) to be picked.

10. The harvesting method of the flexible multi-joint harvesting robot according to claim 9, characterized in that: In step 1, the flexible multi-joint picking robot is also equipped with a spiral spring adjustment block (7). By adjusting the vortex spring adjusting block (7), the position of the outer end of the vortex spring (6) relative to the sheet column (5) is changed, thereby changing the angle range between the single joint thumb (2) and the lowermost flexible phalanges of the two multi-joint main fingers (3), so that it can adapt to the shape and size of the fruits and vegetables (8) to be picked; In step 3, if the fruit and vegetable to be harvested (8) is a hard fruit and vegetable, the fruit and vegetable is harvested by clamping force; if it is a soft fruit and vegetable, the root of the fruit and vegetable to be harvested (8) is cut and harvested by cutting mechanism (4).

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