Single fruit picking manipulator with variable structure

Abstract

The invention discloses a single fruit picking manipulator with a variable structure, which relates to the field of agricultural picking robots and specifically comprises a flexible finger, a telescopic finger, a manipulator platform, a lifting platform, a pitching platform, a lead screw nut, a motor and the like. The flexible fingers and the telescopic fingers are circumferentially installed on the pitching table and the mechanical arm platform at equal intervals, and the angle of the pitching table and the distance between the fingers are controlled by driving the lead screw nut and the lifting table through the motor. The flexible finger drives the belt wheel and the driving wheel through the motor, so that the driven wheel and the conveying belts rotate, actions such as in-palm pulling, twisting and bending are completed through the rotating direction and speed difference of all the conveying belts, and pose adjustment of fruits in the single fruit picking process is achieved. The telescopic fingers control the synchronous belt wheel and the rotating shaft to rotate through the stepping motor, so that the pins move along the grooves, the fingertips stretch out and draw back and press fruit stems, and fruit and plant separation is completed, and the problems of fruit damage and plant collision caused by too large single fruit picking action of a traditional mechanical arm are effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of agricultural picking robots, and in particular to a single-fruit picking manipulator with a variable structure, which is suitable for harvesting single-fruit crops such as apples, tomatoes, and kiwis in complex scenarios. Background Art

[0002] Mechanical harvesting of fruits and vegetables involves a harvesting robot applying sufficient gripping force to the target fruit, supplemented by appropriate motion planning, to separate the fruit from the stem. The fruit-stem separation force and the resulting harvesting outcome are significantly influenced by factors such as fruit stiffness, stem characteristics, and the separation mode. Three separation modes can be categorized based on the load type: bending, torsion, and pulling.

[0003] Traditional single-fruit picking devices (such as those in patents CN118266328A and CN108901363B) rely on the end of a robotic arm to perform pulling, bending, or twisting movements to separate the fruit stems. These large movements and complex trajectories can easily cause branch and leaf collisions, making them unsuitable for complex picking scenarios. Therefore, there is an urgent need for a single-fruit picking robot that integrates "in-situ adjustment and fixed-point separation" to achieve in-palm position adjustment of the fruit and enable precise and efficient harvesting. Summary of the Invention

[0004] The main purpose of this invention is to propose a single-fruit picking robot with a variable structure, which aims to effectively solve the problems of fruit damage and plant collision caused by large-scale bending, twisting and pulling actions of traditional robotic arms during picking through flexible posture adjustment and precise fruit stem separation technology.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A single-fruit picking manipulator with a variable structure mainly includes two groups of flexible fingers, one group of telescopic fingers, a manipulator platform, a lifting platform, a pitching platform, a connecting rod, a screw nut, a U-shaped support and a motor;

[0007] Optionally, the number of flexible fingers is two and they are mounted on the pitching platform of the picking manipulator;

[0008] The entire structure of the telescopic finger is fixed on a U-shaped support, which is fixed on the pitch platform;

[0009] Optionally, the number of the pitching platform and the connecting rod is three, one side of the pitching platform is connected to the connecting rod, and the other side is connected to the lifting platform, and the pitching platform and the connecting rod are equidistantly installed on the manipulator platform;

[0010] The motor is fixed under the manipulator platform. The motor shaft adopts a screw structure and cooperates with the lead screw nut. The lead screw nut is fixed on the lifting platform to adjust the height of the lifting platform and the pitching angle of the lifting platform.

[0011] The flexible finger includes a flexible finger skeleton, a driving wheel, a driven wheel, a conveyor belt, a bearing, a shaft, a pin shaft, a large pulley, a small pulley, a belt, a setscrew, a motor, a motor base and a base;

[0012] The flexible finger skeleton is fixed on the motor base, and the motor base is connected to the base and fixed on the pitching platform;

[0013] Two motors are respectively fixed on both sides of the motor base. A small pulley is fixed on each motor shaft through a setscrew. The large pulley and the driving wheel are fixed on the shaft through setscrews. The large pulley and the small pulley transmit power through a belt;

[0014] Optionally, there are two large pulleys, small pulleys, belts, driving wheels and motors on each flexible finger;

[0015] Bearings are fixed on both sides of the driven wheel and arranged on the pin shaft;

[0016] Optionally, the number of bearings on each driven wheel is two;

[0017] Optionally, the number of conveyor belts on each flexible finger is two. Each conveyor belt is arranged on a driving wheel and three driven wheels. The driving wheel and the driven wheels are fixed around the flexible finger skeleton;

[0018] The telescopic finger includes a fingertip, an elastic rod, a bracket, a telescopic finger base, a static shaft, a slider, a pin, a spring, a rotating shaft, a stepper motor, a large bearing, a large synchronous pulley, a synchronous belt, a small synchronous pulley;

[0019] The fingertip is fixed on the elastic rod, and the elastic rod is fixed on the slider;

[0020] Optionally, the number of elastic rods is two;

[0021] The bracket is fixed on the side plate of the telescopic finger base through screws. Two static shafts are fixed between the bracket and the bottom plate of the telescopic finger base for the up and down sliding of the slider. A spring is arranged between the slider on each static shaft and the bottom plate of the telescopic finger base for the rebound of the slider;

[0022] A rotating shaft is arranged in the middle of the slider. A pin is fixed at the front end of the slider. The pin cooperates with the groove on the rotating shaft. The rotation of the rotating shaft can drive the pin, the slider and the fingertip to move up and down;

[0023] A large bearing is arranged on the rotating shaft and fixed on the bottom plate of the telescopic finger base. A large synchronous pulley is fixed at the tail of the rotating shaft and is in belt transmission with the small synchronous pulley fixed on the shaft of the stepper motor through a synchronous belt. At the same time, the stepper motor is fixed on the bottom plate of the telescopic finger base; when the stepper motor rotates, it drives the synchronous pulley and the rotating shaft to rotate, and makes the pin move along the groove track of the rotating shaft, thereby driving the slider and the fingertip to move up and down reciprocally, realizing the action of pressing the fruit stalk by the fingertip and separating it.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) For the variable-structure manipulator for single-fruit picking of the present invention, through the rotation directions and rotational speed differences of the motors in the two groups of flexibilities, the four conveyor belts on the two groups of flexible fingers can be controlled to perform coordinated movements, thereby adjusting the pose of the grasped fruit and realizing the twisting, pulling, and bending actions within the mechanical palm, solving the problems of fruit damage and plant collision caused by large-scale movements during traditional manipulator picking. (2) During the single-fruit picking process, the rotating shaft is controlled by a stepper motor to rotate, so that the pin moves along the groove track of the rotating shaft, thereby enabling the slider and the fingertip to perform telescopic movements. When the fruit is adjusted to the optimal pose, the fruit stalk is tightened by the telescopic fingertip, realizing the precise and rapid separation of the fruit from the plant; BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments.

[0026] Figure 1 is a schematic structural diagram of a variable-structure manipulator for single-fruit picking;

[0027] Figure 2 is a schematic diagram of a flexible finger;

[0028] Figure 3 is a schematic diagram of a telescopic finger.

[0029] In the figure, 1 is a flexible finger, 2 is a telescopic finger, 3 is a U-shaped support, 4 is a pitching platform, 5 is a connecting rod, 6 is a lifting platform, 7 is a lead screw nut, 8 is a manipulator platform, 9 is a motor, 1-1 is a driven wheel, 1-2 is a bearing, 1-3 is a pin shaft, 1-4 is a flexible finger skeleton, 1-5 is a conveyor belt, 1-6 is a small pulley A, 1-7 is a belt A, 1-8 is a large pulley A, 1-9 is a setscrew, 1-10 is a motor A, 1-11 is a motor base, 1-12 is a base, 1-13 is a shaft, 1-14 is a motor B, 1-15 is a driving wheel, 1-16 is a large pulley B, 1-17 is a small pulley B, 1-18 is a belt B, 2-1 is a fingertip, 2-2 is an elastic rod, 2-3 is a bracket, 2-4 is a telescopic finger base, 2-5 is a static shaft, 2-6 is a slider, 2-7 is a pin, 2-8 is a spring, 2-9 is a rotating shaft, 2-10 is a stepper motor, 2-11 is a large bearing, 2-12 is a large synchronous pulley, 2-13 is a synchronous belt, 2-14 is a small synchronous pulley. DETAILED DESCRIPTION OF THE INVENTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0031] An embodiment of the present invention provides a single-fruit picking manipulator with a variable structure. Refer to Figures 1 to 3 . Figure 1 As shown in the schematic diagram of the variable structure of the single-fruit picking manipulator, flexible fingers 1 and telescopic fingers 2 are arranged equidistantly in a circle on the pitching platform 4. A U-shaped support 3 is used to connect the telescopic fingers 2 and the pitching platform 4 in the middle. At both ends of the pitching platform 4, one side is connected to the connecting rod 5, and the other side is connected to the lifting platform 6; the lifting platform 6 is fixed on the screw nut 7, and the screw nut 7 is in threaded cooperation with the screw on the motor 9; the motor 9 is fixed on the manipulator platform 8, and at the same time, the other end of the connecting rod 5 is connected to the boss around the manipulator platform 8.

[0032] Figure 2 As shown in the schematic diagram of the flexible finger, bearings 1-2 are fixed at both ends of each driven wheel 1-1. The driven wheel 1-1 is fixed on the pin shaft 1-3, and the pin shaft 1-3 is fixed around the flexible finger skeleton 1-4; the flexible finger skeleton 1-4 is fixed on the motor base 1-11 by screws, and the motor base 1-11 is fixed on the base 1-12; at the same time, the motor A1-10 and the motor B1-14 are respectively arranged on both sides of the motor base 1-11. Among them, the large pulley A1-8 is fixed on the motor shaft of the motor A1-10 by a setscrew 1-9, the small pulley A1-6 is fixed on the shaft 1-13 by a setscrew, and the small pulley A1-6 and the large pulley A1-8 are driven by a belt A1-7; similarly, the driving wheel 1-15 and the large pulley B1-16 are fixed on the motor shaft of the other side motor B1-14 by a setscrew 1-9, and the large pulley B1-16 and the small pulley B1-17 fixed on the shaft 1-13 are driven by a belt B1-18. When the motor B1-14 and the motor A1-10 rotate, the driving wheels 1-15 on both sides are driven to rotate through belt transmission, so that the two conveyor belts 1-5 on the flexible finger 1 rotate. By controlling the rotation speed and direction of the two motors, the speed difference and movement direction of the conveyor belt 1-5 can be controlled;

[0033] Figure 3The figure shows a schematic diagram of a telescopic finger. The fingertip 2-1 is fixed on the elastic rod 2-2. The other end of the elastic rod 2-2 is fixed on the slider 2-6. The slider 2-6 cooperates with two static shafts 2-5 and can slide up and down on them. One end of the two static shafts 2-5 is fixed on the bracket 2-3, and the other end is fixed on the bottom plate of the telescopic finger base 2-4. The bracket 2-3 is fixed on the side plate of the telescopic finger base 2-4 by screws. A spring 2-8 is installed on a part of the static shaft 2-5 between the slider 2-6 and the bottom plate of the telescopic finger base 2-4. A pin 2-7 is fixed at the front end of the slider 2-6 and is fitted with the rotary shaft 2-9 in the middle. The other end of the pin 2-7 is fitted with a groove on the rotary shaft 2-9. The rotary shaft 2-9 is fixed on the bottom plate of the telescopic finger base 2-4 by a large bearing 2-11. A large synchronous pulley 2-12 is fixed at the end of the rotary shaft 2-9 by a set screw. A small synchronous pulley 2-14 is fixed on the stepping motor 2-10. The small synchronous pulley 2-14 and the large synchronous pulley 2-12 are driven by a synchronous belt 2-13. The stepping motor 2-10 is fixed on the telescopic finger base 2-4. The rotation of the stepping motor 2-10 drives the rotary shaft to rotate through belt drive, thereby driving the pin 2-7 to move in the groove, so as to realize the up and down movement of the slider 2-6 driving the fingertip 2-1.

[0034] Refer to Figures 1 to 3 The following is the working process of a variable-structure single-fruit picking manipulator of the present invention: During the single-fruit picking process of the manipulator, the rotation of the motor 9 drives the lead screw nut 7 and the lifting table 6 to move up and down, thereby controlling the tilt angle of the pitching table 4 to adjust the distance between the flexible finger 1 and the telescopic finger 2 and the grasping force of the fruit.

[0035] When the manipulator grasps the fruit, it starts to change the posture of the fruit to make it easy to pick. Through the soft fin-shaped structure of the flexible finger skeleton 1-4, it can adapt to the grasping operations of fruits with different hardnesses. The motors A1-10 and B1-16 on the motor base 1-1 drive the large pulleys A1-8 and B1-16 to rotate, and drive the small pulleys A1-6 and B1-17 to rotate through the belts A1-7 and B1-18. The small pulleys A1-6, B1-17 and the driving wheel 1-15 are fixed on the shaft 1-13 by set screws. The rotation of the small pulleys A1-6 and B1-17 drives the driving wheel 1-15 to rotate. The driving wheel 1-15 then transmits the power to the conveyor belt 1-5 and the driven wheel 1-1. By using the rotation speed and rotation direction of the motors A1-10 and B1-16, the rotation direction and speed difference of each conveyor belt 1-5 are controlled to complete actions such as in-palm pulling, twisting and bending, so as to realize the pose adjustment of the fruit during the single-fruit picking process, and effectively solve the problems of fruit damage and plant collision caused by excessive single-fruit picking actions of traditional manipulators.

[0036] When the posture of the fruit is adjusted to a position suitable for picking, the small synchronous pulley 2-14 is controlled to rotate by the stepper motor 2-10, and the synchronous belt 2-13 is used to transmit power to the large synchronous pulley 2-12, and the large synchronous pulley 2-12 is fixed on the rotating shaft 2-9; the groove on the rotating shaft 2-9 is used to make the pin 2-7 move along the groove, and the slider 2-6 moves along the axial direction of the static shaft 2-5, and is rebounded by the spring 2-8; the movement of the slider 2-6 drives the elastic rod 2-2 and the fingertip 2-1 to perform telescopic movement, and the fingertip 2-1 is used to press the fruit stem, thereby realizing the effective separation of the fruit from the plant.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A single-fruit picking manipulator with a variable structure, characterized in that: It includes flexible fingers, telescopic fingers, a manipulator platform, a lifting platform, a pitching platform, connecting rods, a screw nut, a U-shaped support, and a motor; the flexible fingers and telescopic fingers are installed on the pitching platform, the pitching platform and the connecting rods are circumferentially and equidistantly installed on the manipulator platform and the lifting platform, and the motor is installed at the bottom of the manipulator platform.

2. The single-fruit picking manipulator with variable structure according to claim 1, characterized in that: The lifting platform and the screw nut are in threaded cooperation with the screw on the motor shaft. The rotation of the motor drives the movement of the lifting platform and the screw nut, thereby adjusting the angle of the pitching platform and realizing the adjustment of the distance between the flexible fingers and the telescopic fingers, making it suitable for various fruit sizes.

3. The single-fruit picking manipulator with variable structure according to claim 1, characterized in that: The flexible finger is composed of a flexible finger skeleton, a driving wheel, a driven wheel, a conveyor belt, a bearing, a shaft, a pin shaft, a large pulley, a small pulley, a belt, a setscrew, a motor, a motor seat, and a base; the flexible finger skeleton is a fin-shaped soft structure to adapt to the tender surfaces of various fruits and vegetables; the flexible finger skeleton is fixed on the motor seat, the motor is fixed on both sides of the motor seat, and the motor seat is fixed on the base.

4. The flexible finger according to claim 3, characterized in that: Two shafts and two pin shafts are fixed on the flexible finger skeleton. Two driven wheels are fixed on each pin shaft, and one driven wheel and one driving wheel are fixed on each shaft. The driven wheels are connected to the shafts and pin shafts through bearings. The driving wheel is fixed on the shaft by a setscrew. The driving wheel and the driven wheel are connected and driven by a conveyor belt; a large pulley is also fixed on the shaft and is in belt drive with the small pulley fixed on the motor; the rotation of the motor drives the rotation of the pulley and the driving wheel, realizing the rotation direction and speed of the conveyor belt on the flexible finger, thereby realizing the in-palm adjustment of the posture of the grasped fruit.

5. The telescopic finger according to claim 1, characterized in that: The telescopic finger is composed of a fingertip, an elastic rod, a bracket, a telescopic finger base, a static shaft, a slider, a pin, a spring, a rotating shaft, a stepper motor, a large bearing, a large synchronous pulley, a synchronous belt, and a small synchronous pulley; the fingertip is fixed on the elastic rod, and the other end of the elastic rod is fixed on the slider; two static shafts and one rotating shaft are arranged on the slider, and the slider can perform reciprocating linear motion on the static shafts, and the rotating shaft can perform rotational motion in the slider.

6. The rotating shaft according to claim 5, characterized in that: There is a circle of grooves on the circumferential surface of the rotating shaft, which cooperate with the pins fixed on the slider. The rotation of the rotating shaft can make the pins move reciprocally along the groove track; the end of the rotating shaft is fixed with a bearing and a large synchronous pulley, and the outer surface of the bearing is fixed on the bottom plate of the telescopic finger base.

7. The large synchronous pulley according to claim 5, wherein: The large synchronous pulley and the small synchronous pulley fixed at the end of the stepper motor are in belt drive through the synchronous belt.

8. The telescopic finger base according to claim 5, wherein: The stepper motor is fixed on the telescopic finger base, its side plate is fixed with a bracket, and the static shaft is fixed between the bracket and the bottom plate of the telescopic finger base; the spring is sleeved on the circumferential surface of the static shaft and is arranged between the slider and the bottom plate of the telescopic finger base.

9. The telescopic finger according to claim 1, wherein: There is a group of telescopic fingers, which can be controlled by the stepper motor. The synchronous pulley and the rotating shaft rotate, making the pins move along the groove track, so that the slider and the fingertip perform telescopic motion, realizing the pressing of the fruit stalk and completing the separation action of the fruit from the plant.

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