CN-122004048-A - Self-adaptive fruit picking method and system

CN122004048ACN 122004048 ACN122004048 ACN 122004048ACN-122004048-A

Abstract

The invention belongs to the technical field of agricultural picking, and particularly relates to a fruit self-adaptive picking method and system, wherein the method comprises the following steps of forming a bionic cobweb grabbing mechanism by interweaving flexible fine wires to contact the surface of a fruit, and obtaining an intersection point grabbing force at each intersection point; the method comprises the steps of collecting touch information between a fruit and a grid-shaped grabbing surface in real time, wherein the touch information comprises space force distribution, contact area and micro-slippage indexes, respectively obtaining real-time total grabbing force and wrapping force of the grid-shaped grabbing surface on the fruit based on the intersection grabbing force, the space force distribution and the contact area, inputting the real-time total grabbing force, the wrapping force and the micro-slippage indexes into a preset maturity judging module, obtaining maturity grade of the fruit in real time, dynamically adjusting grabbing force according to the maturity grade and the preset target grabbing force, and executing picking action. Through accurate perception touch information and maturity, can realize the harmless picking of fruit, avoid the fruit damage that causes because of excessive centre gripping or dynamics are not enough.

Inventors

NI XINDONG
WU HAO
LI FANGLEI
XU TIANZE
HE ZHIZHU

Assignees

中国农业大学

Dates

Publication Date: 20260512
Application Date: 20260327

Claims (9)

1. An adaptive fruit picking system, comprising: The bionic spider-web grabbing mechanism comprises an actuator module and two oppositely arranged grid-shaped grabbing surfaces, wherein the grid-shaped grabbing surfaces are of grid-shaped structures formed by weaving a plurality of flexible thin wires, contact blocks made of magneto-elastic materials are arranged at the intersection points of the thin wires in the grid-shaped grabbing surfaces, the contact blocks are used for generating magnetic field changes when being stressed and deformed, the actuator module comprises a driver and two picking arms, the driver is provided with two moving ends, the two moving ends are respectively fixed with the corresponding grid-shaped grabbing surfaces through one picking arm, and the driver is used for driving the two picking arms to move oppositely or reversely through the two moving ends so as to realize grabbing and picking of fruits by the two grid grabbing surfaces; the acquisition module comprises sensors which are in one-to-one correspondence with the contact blocks, the sensors are respectively fixed on the corresponding contact blocks, and the sensors are used for monitoring the magnetic field change of the contact blocks when the contact blocks deform in real time; The first processor is electrically connected with the plurality of sensors and is used for acquiring the grabbing force of the intersection points of the contact blocks according to the magnetic field changes fed back by the sensors in real time and acquiring the effective contact area and microslip indexes of the grid grabbing surface and the fruits through the real-time changes of the grabbing force of the intersection points; the second processor is electrically connected with the first processor and is used for acquiring the real-time total grabbing force and the wrapping force of the grid grabbing surface on the fruits through the effective contact area and the grabbing force of each intersection point; The maturity judging module is electrically connected with the first processor and the second processor respectively and is used for classifying the maturity of the fruits through the real-time total grabbing force, the wrapping force and the micro-slippage index; And the third processor is respectively and electrically connected with the second processor, the maturity judging module and the driver, and is used for matching with a preset target grabbing force through the maturity grade, dynamically adjusting the real-time total grabbing force of the two grid grabbing faces to fruits through the driver based on a matching result, and simultaneously acquiring real-time execution grabbing force until the real-time execution grabbing force reaches the preset target grabbing force so as to finish nondestructive picking of the fruits.
2. The fruit adaptive picking system of claim 1, wherein the contact block of magneto-elastic material comprises a ferromagnetic alloy, a magnetic rubber, or a magnetic polymer.
3. The fruit adaptive picking system of claim 1, wherein the contact block corresponding intersection gripping force is determined according to the following equation: , Wherein, the An intersection grabbing force of the contact block at the fine line intersection point P i ; The stiffness coefficient of the contact block is the intersection point P i ; is the contact patch deformation at the thin line intersection point P i .
4. A fruit adaptive picking system according to claim 3 wherein the real time total grabbing force of the grid-like grabbing surface against the fruit is determined according to the following equation: , Wherein, the The real-time total grabbing force of the grid grabbing surface to fruits is V, the volume of the grid grabbing surface; for the spatial force distribution of the grid-like gripping surface in the x, y and z directions, , The component of the intersection gripping force in the x-direction for the fine line intersection point P i ; the component of the intersection gripping force in the y-direction for the fine line intersection point P i ; The component of the intersection gripping force in the z-direction for the fine line intersection point P i , i=1, 2,3.
5. The fruit adaptive picking system of claim 3 wherein the real-time wrapping force of the lattice-like grasping face against the fruit is determined according to the following formula: , Wherein, the Real-time wrapping force of the grid-shaped grabbing surface on the fruits, S is effective contact area of the fruits and the grid-shaped grabbing surface, , For the fruit to contact the effective number of contact pads in the latticed gripping surface, Grabbing the surface area of each grid in the surface for the grid shape; for the spatial force distribution of the grid-like gripping surface in the x, y and z directions, , The component of the intersection gripping force in the x-direction for the fine line intersection point P i ; the component of the intersection gripping force in the y-direction for the fine line intersection point P i ; The component of the intersection gripping force in the z-direction for the fine line intersection point P i , i=1, 2,3.
6. The fruit adaptive picking system of claim 1, wherein the preset maturity discrimination module determines according to the following formula: , wherein: scoring the maturity of the fruit; The total grabbing force is real-time; is the real-time wrapping force; A is effective contact area; The standard grabbing force of the similar fruits obtained in the trial picking stage is obtained; the standard wrapping force of the similar fruits obtained in the trial picking stage under the standard hardness is used; The standard contact area of the similar fruits obtained in the trial picking stage is used under the standard hardness; 、、 And Are all weighting coefficients.
7. The fruit adaptive picking system of claim 6, wherein the maturity rating is partitioned based on a maturity score and a trial harvest threshold of the fruit, the fruit maturity rating comprising Class I-immature, class II-adapted harvest and Class III-overripe, determined according to the following formula: Class I-immature: M > M 1 ; Class II-adapted, M 2 ≤M≤M 1 ; Class III-overripening, M < M 2 ; Wherein M is fruit test picking hardness, M 1 is upper threshold limit of fruit test picking hardness, and M 2 is lower threshold limit of fruit test picking hardness.
8. The fruit adaptive picking system of claim 6, wherein the real-time execution of the grasping force is determined according to the following equation: , Wherein, the In the formula, The grabbing force is executed in real time; The target grabbing force is preset; real-time total grabbing force for grid grabbing the fruits; The feedback adjustment coefficient is used for adjusting the response of the feedback force; The standard proportion coefficient is used in the trial production state; scoring the maturity of the fruit; a central scoring value for the pilot production level; is a sensitivity adjustment factor.
9. A method of adaptive fruit picking, implemented by an adaptive fruit picking system according to any of the preceding claims 1-8, comprising the steps of: The actuator module drives the two grid-shaped grabbing surfaces to contact with the surface of the fruit; collecting the magnetic field change of the contact blocks at each intersection point on the grid-shaped grabbing surface after being stressed by using a plurality of sensors; Acquiring an intersection point grabbing force at each intersection point based on the magnetic field change after stress of each contact block, and acquiring an effective contact area and a micro-slippage index of the latticed grabbing surface and the fruit by utilizing the real-time change of the intersection point grabbing force; respectively acquiring real-time total grabbing force and wrapping force of the grid grabbing surface on the basis of grabbing force of each intersection point and effective contact area; inputting a preset maturity judging module based on the real-time total grabbing force, the wrapping force and the micro-slippage index, and classifying the maturity of the fruits; And matching based on the maturity level and a preset target grabbing force, and acquiring real-time execution grabbing force based on a matching result and a real-time total grabbing force of the grid grabbing surface on fruits until the real-time execution grabbing force reaches the preset target grabbing force, and feeding back the real-time execution grabbing force to an executor module to finish nondestructive picking of the fruits.

Description

Self-adaptive fruit picking method and system Technical Field The invention belongs to the technical field of agricultural picking, and particularly relates to a fruit self-adaptive picking method and system. Background Fruit picking is a simple and key ring in an agricultural production chain, and is used for not only completing rapid collection of fruits in the field, but also ensuring that the appearance and internal quality of the fruits are not damaged in the picking process. Traditional manual picking relies on the tactile experience of the operator to determine the gripping force and the picking timing, which has an inherent advantage in flexibility, but suffers from bottlenecks in manual starvation, scale and standardized work. Therefore, the introduction of robots and automated picking equipment to increase efficiency and reduce labor intensity is a necessary trend. Currently, the main current automatic picking end mainly comprises three types of rigid or semi-rigid grippers, negative pressure suction cups and flexible soft grippers. The rigid or semi-rigid clamp holder is reliable in positioning and bearing, but high in local contact pressure due to the rigidity of a contact surface, indentations or internal tissue damage are easily generated on the surfaces of soft fruits such as strawberries, tomatoes and kiwi fruits, the negative pressure sucker is sensitive to surface smoothness and morphology, and the adsorption effect is reduced and the falling risk exists when the negative pressure sucker is wet or the peel is concave-convex. The soft/flexible gripper disperses contact pressure through material or structure flexibility, and progress is made in the aspect of damage compared with a rigid or semi-rigid gripper and a negative pressure sucker, but the purely passive flexibility is difficult to accurately adjust the grabbing force according to fruits with different maturity, and the problem of fruit damage caused by the difference of grabbing force still remains a main defect in the current picking process. For example, the patent number CN110432000A provides a fruit and vegetable picking actuator based on the integration of flexible gripping and clamping and shearing and a picking method thereof, which provides structural improvement of combining the functions of flexible gripping and clamping and shearing so as to reduce picking damage and give consideration to efficiency, and for example, the patent number CN108738702B provides a peeling type apple picking device which focuses on the end mechanism design of the picking actuator and comprises a mechanism such as fruit handle positioning, elastic buffering and the like. Although the damage of picking is relieved from different angles, most of the two schemes stay on the structure or static detection level, and the picking strategy is difficult to be adaptively adjusted according to the change of the contact force so as to adapt to picking fruits with different maturity, and the damage rate caused by picking is high. Disclosure of Invention In order to solve the problems in the prior art, the invention aims to provide the fruit self-adaptive picking method which can finish the self-adaptive adjustment of the grabbing force by accurately sensing the touch information and the maturity, realize the nondestructive picking of fruits and avoid the damage of the fruits caused by excessive clamping or insufficient force. The technical scheme of the invention is as follows: an adaptive fruit picking system comprising: The bionic spider-web grabbing mechanism comprises an actuator module and two oppositely arranged grid-shaped grabbing surfaces, wherein the grid-shaped grabbing surfaces are of grid-shaped structures formed by weaving a plurality of flexible thin wires, contact blocks made of magneto-elastic materials are arranged at the intersection points of the thin wires in the grid-shaped grabbing surfaces, the contact blocks are used for generating magnetic field changes when being stressed and deformed, the actuator module comprises a driver and two picking arms, the driver is provided with two moving ends, the two moving ends are respectively fixed with the corresponding grid-shaped grabbing surfaces through one picking arm, and the driver is used for driving the two picking arms to move oppositely through the two moving ends so as to realize grabbing picking of fruits by the two grid grabbing surfaces; the acquisition module comprises sensors which are in one-to-one correspondence with the contact blocks, the sensors are respectively fixed on the corresponding contact blocks, and the sensors are used for monitoring the magnetic field change of the contact blocks when the contact blocks deform in real time; The first processor is electrically connected with the plurality of sensors and is used for acquiring the grabbing force of the intersection points of the contact blocks according to the magnetic field changes fed back by the sensors in real time