Strawberry picking hand with integrated splitting and clamping function

Abstract

The present invention relates to the technical field of agricultural machinery. The purpose is to provide a strawberry picking hand with integrated splitting and clamping, which should be able to cut and clamp strawberries and have the characteristics of compact structure, smooth movement and high working efficiency. The technical solution is: a strawberry picking hand with integrated splitting and clamping, characterized in that: the picking hand includes a frame, two clamping arms that can be movably positioned on the frame, a steering gear fixed to the frame, a transmission mechanism that transmits the steering gear power to drive the clamping arms to move toward each other, and an elastic member that drives the clamping arms to move in opposite directions; the transmission mechanism includes a pulley block arranged on each clamping arm, a crankshaft driven by the steering gear, and a transmission rope mounted on the pulley block and the crankshaft.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural machinery, in particular to a strawberry picking hand with integrated splitting and clamping. Background Art

[0002] Strawberry is a high-value crop. Although the global strawberry industry has an annual sales value of more than 17 billion US dollars, producers need to spend more than 1 billion US dollars on picking (selective harvesting). Moreover, the domestic labor shortage has increased labor costs, which has an impact on selective harvesting. At present, robots have been partially used to harvest strawberries in China, but due to various scientific and technological limitations, there are still many unresolved issues in strawberry harvesting. First of all, the flexibility and efficiency of the robot end effector is an unresolved issue. Most of the selective harvesters used can only perform two actions (opening the gripper head and closing the gripper head). Since strawberries are extremely easy to be damaged and bruised, in order to ensure the integrity during harvesting, it is necessary to design a device that can grasp, separate and process strawberries from the stem without touching the strawberries, so as to reduce abrasions and breakages, extend the shelf life of strawberries, and reduce unnecessary waste. This is very important for handling soft fruits (strawberries).

[0003] The strawberry picking robots currently in use at home and abroad mainly use cup-shaped picking heads (Autonomous Strawberry Picking Robotic System (Robofruit) DOI:arxiv-2301.03947), which have an opening that can locate the inflorescence stalk of the strawberry and place the strawberry in front of the scissors for harvesting. The cutting action will cause the strawberries to fall off the plant and fall into the water net that collects the strawberries. Although it will not directly contact the strawberry pulp, it is still possible to inadvertently damage and scratch the fruit. Therefore, most cup-shaped picking heads (and other types of picking heads) are still not suitable for harvesting crops that grow in dense clusters. Summary of the invention

[0004] The object of the present invention is to overcome the deficiencies in the above-mentioned background technology and to provide a strawberry picking hand with integrated splitting and clamping, which can realize the cutting and clamping of strawberries and has the characteristics of compact structure, smooth movement and high working efficiency.

[0005] The technical solution of the present invention is:

[0006] A strawberry picking hand with integrated splitting and clamping, characterized in that: the picking hand comprises a frame, two clamping arms movably positioned on the frame, a steering gear fixed to the frame, a transmission mechanism for transmitting the steering gear power to drive the clamping arms to move toward each other, and an elastic member for driving the clamping arms to move in opposite directions; the transmission mechanism comprises a pulley block arranged on each clamping arm, a crankshaft driven by the steering gear, and a transmission rope mounted on the pulley block and the crankshaft.

[0007] The pulley block comprises a first pulley, a second pulley and a third pulley which are alternately arranged left and right; the second pulley is arranged close to the inner side of the clamping arm, and the first pulley and the third pulley are arranged close to the outer side of the clamping arm.

[0008] The crankshaft includes a transmission plate fixed to the steering gear shaft and a transmission pin arranged on the transmission plate; when the clamping arms are opened, the transmission pin is located between the planes where the clamping surfaces of the two clamping arms are located; when the crankshaft rotates counterclockwise, the two clamping arms are driven to move toward each other simultaneously through the transmission pin, the transmission rope and the pulley group.

[0009] The winding path of the transmission rope is: the transmission rope first passes through the first pulley, the second pulley and the third pulley of the left clamp arm from top to bottom, then wraps around the transmission pin once, then passes through the third pulley, the second pulley and the first pulley of the right clamp arm from bottom to top, and finally returns to the first pulley of the left clamp arm;

[0010] Alternatively, the transmission disk is also provided with a left connecting shaft and a right connecting shaft, the left end of the transmission rope passes around the first pulley, the second pulley and the third pulley of the left clamping arm from top to bottom in sequence, then wraps around the transmission pin once, and then is fixed to the right connecting shaft, the right end of the transmission rope passes around the first pulley, the second pulley and the third pulley of the right clamping arm in sequence from top to bottom, then passes around the transmission pin, and then is fixed to the left connecting shaft.

[0011] Annular grooves are arranged on the outer circumferential surfaces of the first pulley, the second pulley, the third pulley and the transmission pin; and the transmission pin is rotatably positioned on the transmission disc.

[0012] The elastic member is a rubber band connecting the clamp arm and the frame; when the crankshaft rotates clockwise, the elastic member drives the clamp arm to move in the reverse direction.

[0013] The clamp arm is provided with a first connecting column connected to a rubber band.

[0014] The frame is provided with a guide rail, and the clamping arm is slidably positioned on the guide rail through a slider; a blade is provided on the clamping surface of one of the clamping arms, and a knife groove is provided on the clamping surface of the other clamping arm.

[0015] The clamp arm is provided with a buffer plate, which is slidably positioned on the clamp arm through a guide rod, and a buffer spring is provided between the buffer plate and the clamp arm; a blade is provided on the clamping surface of one of the buffer plates, and a knife groove is provided on the clamping surface of the other buffer plate.

[0016] Limiting plates are arranged on both sides of the frame.

[0017] The beneficial effects of the present invention are:

[0018] 1. The invention has a compact structure and an ingenious design. The cutting and clamping of the rhizomes are completed by the cooperation of the blade groove, the transmission mechanism and the elastic member. It can not only directly cut off the rhizomes of strawberries and avoid direct contact with the strawberries during clamping, but also reduce the control accuracy requirements, greatly improve the integrity of picking, and improve the efficiency of harvesting;

[0019] 2. The present invention realizes the synchronous movement of the two clamping arms through a simplified steering gear driving transmission rope, and then ensures that the clamping arms have a stable movement trajectory through a linear guide rail, which is conducive to clamping the rhizomes. When the clamping arms are closed, the upper rhizomes are cut to separate the strawberries from the stems; at the same time, the blades are replaceable, which is convenient for later maintenance;

[0020] 3. The present invention is installed at the end of the picking robot, with an overall structure that is small and compact, low cost, stable in operation and high in efficiency. It is suitable for most fruit picking tasks, avoids contact with the fruit, reduces abrasion damage, ensures the integrity of the picking, greatly extends its shelf life, and effectively improves the economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is one of the three-dimensional structural schematic diagrams of the present invention.

[0022] Figure 2 This is the second schematic diagram of the three-dimensional structure of the present invention.

[0023] Figure 3 It is one of the main structural schematic diagrams of the present invention (open state).

[0024] Figure 4 This is the second main structural schematic diagram of the present invention (closed state).

[0025] Figure 5 It is a schematic diagram of the top structure of the present invention.

[0026] Figure 6 It is a right-side structural schematic diagram of the present invention.

[0027] Figure 7 It is a three-dimensional structural schematic diagram of the guide rail of the present invention.

[0028] Figure 8 It is one of the three-dimensional structural schematic diagrams of the clamp arm of the present invention.

[0029] Fig. 9 This is the second schematic diagram of the three-dimensional structure of the clamp arm of the present invention.

[0030] Fig.10 This is the third main structural schematic diagram of the present invention (open state).

[0031] Fig.11 This is the fourth main structural schematic diagram of the present invention (closed state).

[0032] Fig.12 It is one of the schematic diagrams of the transmission rope of the present invention.

[0033] Fig.13 It is the second schematic diagram of the transmission rope of the present invention.

[0034] Fig.14 It is the third schematic diagram of the transmission rope of the present invention.

[0035] Fig.15 It is a schematic diagram of the buffer structure of the present invention.

[0036] Figure numerals: frame 1, clamping arm 2, boss 2.1, servo gear 3, elastic member 4, crankshaft 5, transmission plate 5.1, transmission pin 5.2, left connecting shaft 5.3, right connecting shaft 5.4, transmission rope 6, guide rail 7, slider 8, blade 9, pressure plate 9.1, knife groove 10, first pulley 11, second pulley 12, third pulley 13, limit plate 14, first connecting column 21, second connecting column 22, buffer plate 31, guide rod 32, buffer spring 33, limit block 34, limit rod 35. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] like Figure 1 As shown, a strawberry picking hand with integrated splitting and clamping includes a frame 1, two clamping arms 2, a steering gear 3, a transmission mechanism, and an elastic member 4. The clamping arms can be movably positioned on the frame, the steering gear is fixed to the frame, the transmission mechanism is used to transmit the steering gear power to drive the two clamping arms to move toward each other, and the elastic member is used to drive the two clamping arms to move in opposite directions. Limiting plates 14 are provided on both sides of the frame, and guide rails 7 are also provided on the frame, and the clamping arms can be slidably positioned on the guide rails through sliders 8.

[0039] like Fig. 9 As shown, a blade 9 is provided on the clamping surface of one clamp arm (the side facing the other clamp arm), and the blade is fixed to the clamp arm through a pressure plate 9.1 and a fastener (M2.5 screw) (for convenience of later maintenance). Fig.10As shown, a knife groove 10 cooperating with a blade is provided on the clamping surface of the other clamping arm (the side facing the other clamping arm). When the two clamping arms are closed, the blade is embedded in the knife groove to cut off the strawberry rhizome, and the clamping surfaces on both sides clamp the rhizome (the clamping surfaces still maintain a certain distance and do not completely overlap), avoiding touching the strawberry and realizing non-contact picking.

[0040] The transmission mechanism includes a pulley block, a crankshaft 5, and a transmission rope 6. The two clamp arms are provided with a pulley block, the crankshaft is driven by a steering gear, and the transmission rope is mounted on the pulley block and the crankshaft. When the steering gear drives the crankshaft to rotate counterclockwise ( Figure 3 and Figure 4 The crankshaft pulls down the transmission rope, and the transmission rope drives the two clamping arms to move toward each other through the pulley block, overcoming the resistance of the elastic part. When the servo drives the crankshaft to rotate clockwise ( Figure 3 and Figure 4 The clockwise (clockwise) transmission rope is loosened, and the elastic member drives the two clamp arms to move in opposite directions (the transmission rope remains taut).

[0041] The pulley block includes a first pulley 11, a second pulley 12, and a third pulley 13. Figure 3 As shown, the first pulley, the second pulley, and the third pulley of each pulley group are arranged alternately from left to right, the second pulley is arranged close to the inner side of the clamp arm (the side close to the clamping surface), the first pulley and the third pulley are arranged close to the outer side of the clamp arm (the side away from the clamping surface), and the first pulley, the second pulley, and the third pulley are arranged in sequence from top to bottom. Figure 3 As shown, the first pulley, the second pulley, and the third pulley are arranged in an isosceles triangle, and the center of each pulley is located at the three vertices of the isosceles triangle.

[0042] The crankshaft includes a transmission disc 5.1 fixed to the steering gear shaft and a transmission pin 5.2 arranged on the transmission disc. The transmission pin is rotatably positioned on the transmission disc. The transmission rope is wound around the pulley set of each clamping arm and the transmission pin. The outer circumferential surfaces of the first pulley, the second pulley, the third pulley and the transmission pin are all provided with an annular groove that matches the transmission rope.

[0043] like Figure 3 , Figure 4 , Fig.12 As shown, the transmission rope is a ring-shaped rope connected end to end, and the winding path of the transmission rope is: the transmission rope first passes through the first pulley (counterclockwise), the second pulley (clockwise) and the third pulley (counterclockwise) of the left clamp arm from top to bottom, then wraps around the transmission pin once (clockwise), and then passes through the third pulley (counterclockwise), the second pulley (clockwise) and the first pulley (counterclockwise) of the right clamp arm from bottom to top, and finally returns to the first pulley of the left clamp arm.

[0044] When the clamping arm needs to be closed, the servo drives the crankshaft to rotate counterclockwise by a certain angle, and the transmission pin moves downward to tighten the transmission rope. The transmission rope then applies tension to the clamping arm through the pulley set, causing the clamping arm to overcome the resistance of the elastic member and move toward each other.

[0045] like Figure 3 As shown in the figure, to ensure that the transmission pin is close to the middle of the frame, the servo is set on the right side of the frame, and the transmission pin is located at the 9 o'clock position of the transmission plate (the clamping arm is fully opened). At this time, the transmission pin is located between the planes where the clamping surfaces of the two clamping arms are located. When the clamping arms perform cutting and clamping actions, the transmission plate rotates 70-90 degrees counterclockwise ( Figure 4 The rotation angle is 86 degrees), the transmission pin moves along an arc trajectory, the speed of the transmission pin in the vertical direction gradually decreases, and the speed of the transmission pin in the horizontal direction gradually increases, so the speed of the clamp arms moving toward each other gradually decreases, at the beginning stage of the movement toward each other, the clamp arms close quickly to cut off the strawberry rhizomes, and at the end stage of the movement toward each other, the clamp arms close slowly to accurately clamp the strawberry rhizomes (the clamp arms are fully tightened).

[0046] Since the transmission pin is in deflection motion, the extension and retraction lengths of the transmission ropes on both sides are inconsistent, resulting in different moving distances of the two clamping arms. Therefore, a left connecting shaft 5.3 and a right connecting shaft 5.4 are added to the transmission disk, and the two ends of the transmission rope are fixed to the left connecting shaft and the right connecting shaft. The right connecting shaft, the left connecting shaft, and the transmission pin are arranged on the transmission disk in sequence along the clockwise direction.

[0047] The angles formed by the connecting lines from the center point of the right connecting shaft, the center point of the left connecting shaft, the center point of the transmission pin to the center of the transmission plate are all 90 degrees.

[0048] like Fig.10 , Fig.11 , Fig.13 , Fig.14 As shown, the transmission rope is a line with the ends disconnected, and the winding path of the transmission rope is: Fig.13 , the left end of the transmission rope passes through the first pulley (counterclockwise), the second pulley (clockwise) and the third pulley (counterclockwise) of the left clamping arm from top to bottom, then wraps around the transmission pin once (clockwise), and then is fixed to the right connecting shaft; Fig.14 The right end of the transmission rope passes through the first pulley (clockwise), the second pulley (counterclockwise) and the third pulley (clockwise) of the right clamp arm from top to bottom, then passes through the transmission pin (counterclockwise), and then is fixed to the left connecting shaft. With this structure, the two clamp arms can move synchronously as much as possible, solving the problem of inconsistent extension and retraction lengths of the left and right transmission ropes caused by the servo offset, and ensuring that the clamp arms are clamped in the center.

[0049] The elastic member connects each clamp arm to the frame respectively, and the elastic member applies a pulling force to the clamp arm so that the two clamp arms move in opposite directions. A first connecting column 21 is provided on the clamp arm, and a second connecting column 22 is provided on both sides of the frame, and the second connecting column is fixed on the limit plate. The elastic member adopts a rubber band, and the rubber band is sleeved on the first connecting column and the limit plate on the same side. The upper end of the rubber band is sleeved on the first connecting column, and after the rubber band goes around the second connecting column, the lower end of the rubber band is sleeved on the bottom of the limit plate. The elastic member can also adopt a spring, and the two ends of the spring are fixed to the first connecting column and the limit plate on the same side.

[0050] When the steering gear drives the crankshaft to rotate clockwise, the transmission rope is gradually released, and the two clamping arms move in opposite directions (towards both sides) under the pulling force of the elastic member, and the transmission rope remains in a tensioned state. The limit plates on both sides of the frame are used to control the maximum opening distance of the clamping arms.

[0051] The servo adopts a 4.8v-6v (20KG) servo, ensuring that the overall structure is compact and simple.

[0052] When picking, the picking hand can easily pierce the ground film covering the soil, so further improvements are made to the picking hand, and a buffer structure is added: a buffer plate 31 is provided on the clamp arm, and the buffer plate can be slidably positioned on the clamp arm through a guide rod 32. A buffer spring 33 is also provided between the buffer plate and the clamp arm, and the sliding direction of the buffer plate is perpendicular to the sliding direction of the slider. The guide rod is fixed on the boss 2.1 on the clamp arm, and the buffer spring is sleeved on the guide rod. One end of the buffer spring supports the buffer plate and the other end supports the boss of the clamp arm. A limit block 34 is provided on the clamp arm, and a limit rod 35 cooperating with the limit block is provided on the buffer plate to control the sliding stroke of the buffer plate. A blade 9 is provided on the clamping surface of one of the buffer plates, and a knife groove (omitted in the figure) is provided on the clamping surface of the other buffer plate. When the picking hand touches the ground film, the buffer plate is blocked and automatically retreats, thereby achieving the purpose of protecting the ground film.

[0053] The picking hand is installed on an external robotic arm, which moves the picking hand to the picking and releasing position. The specific working process of the picking hand is as follows:

[0054] 1. The robotic arm drives the picking hand close to the strawberry, and the clamp arm opens ( Figure 3 As shown, );

[0055] 2. When the strawberry root is between the clamp arms, the servo drives the transmission disc to rotate counterclockwise, the transmission pin tightens the transmission rope, and the transmission rope drives the two clamp arms to move toward each other through the pulley group, so that the clamp arms close ( Figure 4 As shown in the figure, when the blade is inserted into the blade groove, the strawberry rhizome is cut off, and the clamping surface of the clamp arm clamps the rhizome connected to the strawberry, thus realizing contactless picking;

[0056] 3. The robotic arm drives the picking hand into the collection basket, the servo rotates in the opposite direction to release the transmission rope, the elastic part drives the clamping arm to separate, and the strawberries are placed in the collection basket.

[0057] The picking hand can simultaneously cut and clamp the strawberry roots and stems, avoiding direct contact with the strawberries and greatly reducing the probability of abrasions and bruises. It is particularly suitable for picking soft fruits. Compared with the existing strawberry cup picking actuator, it has the characteristics of high efficiency, compact structure, low cost, good benefits, high work efficiency, wide applicability, and standardized mass production.

[0058] The above-mentioned specific embodiments may be partially adjusted in different ways by those skilled in the art without departing from the principles and purpose of the present invention. The protection scope of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementations. Each implementation scheme within its scope shall be subject to the constraints of the present invention.

Claims

1. A strawberry picking hand with integrated splitting and clamping, characterized in that: The picking hand comprises a frame (1), two clamping arms (2) movably positioned on the frame, a steering gear (3) fixed to the frame, a transmission mechanism for transmitting steering gear power to drive the clamping arms to move toward each other, and an elastic member (4) for driving the clamping arms to move in opposite directions; the transmission mechanism comprises a pulley block arranged on each clamping arm, a crankshaft (5) driven by the steering gear, and a transmission rope (6) mounted on the pulley block and the crankshaft; The pulley assembly comprises a first pulley (11), a second pulley (12), and a third pulley (13) which are arranged alternately on the left and right sides; the second pulley is arranged close to the inner side of the clamp arm, and the first pulley and the third pulley are arranged close to the outer side of the clamp arm; The crankshaft comprises a transmission disc (5.1) fixed to the steering gear shaft and a transmission pin (5.2) arranged on the transmission disc; when the clamping arms are opened, the transmission pin is located between the planes where the clamping surfaces of the two clamping arms are located; when the crankshaft rotates counterclockwise, the transmission pin, the transmission rope and the pulley block simultaneously drive the two clamping arms to move toward each other; The winding path of the transmission rope is: the transmission rope first passes through the first pulley, the second pulley and the third pulley of the left clamp arm from top to bottom, then wraps around the transmission pin once, then passes through the third pulley, the second pulley and the first pulley of the right clamp arm from bottom to top, and finally returns to the first pulley of the left clamp arm; Alternatively, the transmission disc is further provided with a left connecting shaft (5.3) and a right connecting shaft (5.4); the left end of the transmission rope passes through the first pulley, the second pulley and the third pulley of the left clamping arm from top to bottom in sequence, then wraps around the transmission pin once, and is then fixed to the right connecting shaft; the right end of the transmission rope passes through the first pulley, the second pulley and the third pulley of the right clamping arm from top to bottom in sequence, then passes around the transmission pin, and is then fixed to the left connecting shaft; When the clamping arms perform cutting and clamping actions, the transmission disk rotates 70-90 degrees counterclockwise, the transmission pin moves along an arc-shaped trajectory, the speed of the transmission pin in the vertical direction gradually decreases, and the speed of the transmission pin in the horizontal direction gradually increases. Therefore, the speed of the clamping arms moving toward each other gradually decreases. At the beginning stage of the movement toward each other, the clamping arms close quickly to cut off the strawberry rhizomes, and at the end stage of the movement toward each other, the clamping arms close slowly to accurately clamp the strawberry rhizomes.

2. The strawberry picking hand with integrated splitting and clamping according to claim 1, characterized in that: Annular grooves are arranged on the outer circumferential surfaces of the first pulley, the second pulley, the third pulley and the transmission pin; and the transmission pin is rotatably positioned on the transmission disc.

3. The strawberry picking hand with integrated splitting and clamping according to claim 2, characterized in that: The elastic member is a rubber band connecting the clamp arm and the frame; when the crankshaft rotates clockwise, the elastic member drives the clamp arm to move in the reverse direction.

4. The strawberry picking hand with integrated splitting and clamping according to claim 3, characterized in that: The clamp arm is provided with a first connecting column (21) for connecting with a rubber band.

5. The strawberry picking hand with integrated splitting and clamping according to claim 4, characterized in that: The frame is provided with a guide rail (7), and the clamping arm is slidably positioned on the guide rail through a slider (8); a blade (9) is provided on the clamping surface of one of the clamping arms, and a knife groove (10) is provided on the clamping surface of the other clamping arm.

6. The strawberry picking hand with integrated splitting and clamping according to claim 5, characterized in that: The clamp arm is provided with a buffer plate (31), which is slidably positioned on the clamp arm through a guide rod (32), and a buffer spring (33) is provided between the buffer plate and the clamp arm; a blade (9) is provided on the clamping surface of one of the buffer plates, and a knife groove is provided on the clamping surface of the other buffer plate.

7. The strawberry picking hand with integrated splitting and clamping according to claim 6, characterized in that: Limiting plates (14) are provided on both sides of the frame.

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