A control method and system for a gripper of a logistics sorting robot

Abstract

This invention relates to the field of robot gripping technology, and more particularly to a control method and system for a gripper of a logistics sorting robot. The method involves determining the thickness and bonding position of a fixed plate, dividing the fixed plate into several gripping areas, collecting driving pressure and driving current to generate drop characterization values ​​to determine the first drop tendency of the logistics packaging box and determine the corresponding reinforcement strategy, determining the adjustment strategy for the gripping task based on the degree of center of gravity shift and the first relative displacement difference, collecting tilt duration and needle spacing to determine the degree of change in the second drop tendency, adjusting the gripping task adjustment strategy in response to the second drop tendency being greater than the first drop tendency, and determining the adjustment strategy for a third gripping task based on the comparison result of the second relative displacement difference and the second displacement threshold. This significantly improves the accuracy of the control method for the gripper of the logistics sorting robot.

Description

Technical Field

[0001] This invention relates to the field of robot grasping technology, and in particular to a control method and system for a gripper of a logistics sorting robot. Background Technology

[0002] With the rapid development of e-commerce and intelligent logistics, logistics sorting robots, as the core execution unit of logistics sorting systems, directly determine the efficiency of the overall sorting process and the integrity of goods through the stability and accuracy of their gripping operations. In practical applications, for logistics packaging boxes containing fragile items, traditional adsorption or clamping methods are prone to slipping or tilting during transfer and sorting due to insufficient friction. Furthermore, applying excessive pressure to the logistics packaging boxes can easily cause damage, affecting the integrity of the goods. Therefore, there is an urgent need for a gripper control method for logistics sorting robots that can achieve pre-grip parameter detection, real-time monitoring of the gripping process status, timely prediction of drop trends, and dynamic reinforcement and adjustment of strategies to improve the accuracy of the gripper's grasping of logistics goods during logistics sorting operations.

[0003] Chinese Patent Publication No. CN115519544A discloses a method, apparatus, device, and storage medium for a fresh produce sorting robot. The method includes: upon receiving a control command to move the robot arm, acquiring target position information and performing a position calibration operation. The position calibration operation includes: acquiring gripper image information; acquiring movement image information within a preset period; calculating the movement distance based on preset gripper size information by comparing the movement image information with the gripper image information; acquiring the theoretical movement distance; calculating the movement error distance; comparing the movement error distance with a preset movement error range; and repeating the position calibration operation until the robot arm moves to the target position information if the movement error distance is within the preset movement error range. The technical effect of this application is that by repeatedly calibrating the gripper, the robot can accurately grasp transported items, thereby improving the gripper's grasping accuracy.

[0004] Therefore, it is evident that the existing technology has the following problems:

[0005] It only predicts the error of the gripper movement, without considering the prediction of the falling trend of logistics goods during the actual gripping process and timely reinforcement, or generating corresponding adjustment strategies for the displacement of goods and grippers after the gripping is completed to improve the accuracy of the next gripping. Summary of the Invention

[0006] To address this, the present invention provides a control method and system for the gripper of a logistics sorting robot, which overcomes the problem in the prior art that only predicts the movement error of the gripper, without considering the prediction of the falling trend of logistics goods during the actual gripping process and timely reinforcement, and generating corresponding adjustment strategies for the displacement of goods and gripper after the gripping is completed to improve the accuracy of the next gripping.

[0007] To achieve the above objectives, in one aspect, the present invention provides a control method for a gripper of a logistics sorting robot, comprising:

[0008] Based on the pre-grabbing of logistics goods by the sorting robot, the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box are determined. The number of gripping times and the total number of fixing needles pierced by the robot gripper in a single puncture are calculated for the sorting process of logistics goods.

[0009] The area of ​​the fixing plate is determined based on the number of gripping attempts and the total number of pins, and the fixing plate is divided into several gripping areas for the first gripping task. The driving pressure of the gripper on the fixing pin and the driving current of the gripper on the fixing pin during the first gripping task are collected to generate a drop characterization value.

[0010] The degree of the first drop trend of the logistics packaging box is determined based on the drop characterization value and the corresponding reinforcement strategy is determined. The drop deviation value is calculated based on the drop characterization value and the first drop threshold to determine the degree of center of gravity displacement of the logistics packaging box. The first relative displacement difference between the gripper and the fixed plate is obtained after the first gripping task is completed.

[0011] The adjustment strategy for the grasping task is determined based on the degree of center of gravity shift and the first relative displacement difference. The adjustment strategy is classified. Based on the first adjustment strategy, the tilt duration and needle spacing during the second grasping task are collected to generate trend feature values ​​to determine the degree of change of the second falling trend. Based on the second adjustment strategy, the second relative displacement difference between the gripper and the fixed plate is collected after the second grasping task is completed.

[0012] In response to the second falling trend being greater than the first falling trend, the adjustment strategy is adjusted, and the adjustment strategy is determined based on the comparison result of the second relative displacement difference and the second displacement threshold to perform the third grabbing task.

[0013] Furthermore, the process of determining the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box based on the pre-grabbing of logistics goods by the sorting robot includes,

[0014] Based on the results of several pre-grabbing operations, the location of the box body corresponding to the location of the fragile items inside the logistics packaging box is determined as the bonding location.

[0015] The thickness of the corresponding fixing plate is determined by collecting the total weight of the logistics goods.

[0016] Furthermore, the process of collecting the driving pressure of the gripper on the fixed pin and the driving current of the gripper on the fixed pin during the first grasping task to generate drop characterization values ​​includes,

[0017] The ratio of the driving pressure to the rated driving pressure is determined as the pressure factor.

[0018] The ratio of the driving current to the rated driving current is determined to be the current factor;

[0019] The weighted sum of the pressure factor and the current factor is determined to be the drop characterization value.

[0020] Furthermore, based on the drop characterization values, the degree of the first drop trend of the logistics packaging box is determined, and the corresponding reinforcement strategy is identified.

[0021] If the drop characterization value is greater than or equal to the first drop threshold, the first drop trend of the logistics packaging box is determined to be a severe drop trend, and the corresponding reinforcement strategy is to increase the number of pins of the gripper drive fixing pin.

[0022] If the drop characterization value is greater than the second drop threshold and less than the first drop threshold, then the first drop trend of the logistics packaging box is determined to be a moderate drop trend, and the corresponding reinforcement strategy is to increase the needle spacing of the gripper drive fixing needle.

[0023] The first drop threshold is greater than the second drop threshold.

[0024] Furthermore, a drop deviation value is calculated based on the drop characterization value and the first drop threshold to determine the degree of center of gravity shift of the logistics packaging box.

[0025] If the drop deviation value is less than the deviation threshold, the degree of displacement of the center of gravity of the logistics packaging box is determined to be slight displacement;

[0026] If the drop deviation value is greater than or equal to the deviation threshold, the degree of center of gravity displacement of the logistics packaging box is determined to be severe displacement.

[0027] Furthermore, an adjustment strategy for the grasping task is determined based on the degree of center of gravity shift and the first relative displacement difference, wherein,

[0028] If the degree of center of gravity shift is determined to be slight and the first relative displacement difference is less than or equal to the displacement threshold, the adjustment strategy of not performing the grasping task is determined.

[0029] If the degree of center of gravity shift is determined to be slight and the first relative displacement difference is greater than the displacement threshold, the adjustment strategy for the grasping task is determined to be to increase the driving distance of the fixed pin.

[0030] If the degree of center of gravity shift is determined to be severe and the first relative displacement difference is less than or equal to the displacement threshold, the adjustment strategy for the grasping task is to thicken the fixing plate.

[0031] If the degree of center of gravity shift is determined to be severe and the first relative displacement difference is greater than the displacement threshold, the adjustment strategy for the grasping task is determined to be to increase the driving distance of the fixed pin and thicken the fixed plate.

[0032] Furthermore, the process of generating trend feature values ​​based on the tilt duration and needle spacing during the second grasping task, using the first adjustment strategy, includes:

[0033] The ratio of the first tilt duration to the second tilt duration is calculated as the duration factor;

[0034] The ratio of the first needle exit distance to the second needle exit distance is calculated as the spacing factor;

[0035] The weighted sum of the duration factor and the interval factor is determined to be the trend characteristic value.

[0036] Furthermore, the degree of change in the second falling trend is determined based on the trend characteristic value, wherein,

[0037] If the trend characteristic value is greater than the trend threshold, then the degree of the second falling trend is determined to be less than the degree of the first falling trend.

[0038] If the trend characteristic value is less than the trend threshold, then the degree of the second falling trend is determined to be greater than the degree of the first falling trend.

[0039] Furthermore, the process of adjusting the adjustment strategy in response to the second falling trend being greater than the first falling trend includes,

[0040] The absolute value of the difference between the trend characteristic value and the trend threshold is determined as the trend difference.

[0041] If the trend difference is less than or equal to the trend difference threshold, then the adjustment strategy is determined to be to thicken the fixing plate.

[0042] If the trend difference is greater than the trend difference threshold, then the adjustment strategy is determined to be to increase the driving distance of the fixed needle and thicken the fixed plate.

[0043] On the other hand, the present invention also provides a control system for a gripper of a logistics sorting robot, comprising:

[0044] The bonding module is used to determine the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box based on the pre-grabbing of logistics goods by the sorting robot, as well as to calculate the number of gripping times and the total number of fixing needles pierced by the robot gripper in a single puncture of the logistics goods sorting process.

[0045] The gripping module, which is connected to the bonding module, is used to determine the area of ​​the fixing plate according to the number of gripping and the total number of pins, and to divide the fixing plate into several gripping areas for the first gripping task, and to collect the driving pressure of the gripper on the fixing pin and the driving current of the gripper on the fixing pin during the first gripping task to generate a drop characterization value.

[0046] The reinforcement module, which is connected to the gripping module, is used to determine the first falling trend of the logistics packaging box based on the falling characterization value and to determine the corresponding reinforcement strategy, and to calculate the falling deviation value based on the falling characterization value and the first falling threshold to determine the degree of center of gravity displacement of the logistics packaging box, and to obtain the first relative displacement difference between the gripper and the fixed plate after the first gripping task is completed.

[0047] The classification module, which is connected to the reinforcement module, is used to determine the adjustment strategy of the grasping task based on the degree of center of gravity shift and the first relative displacement difference, classify the adjustment strategy, and generate trend feature values ​​based on the tilt duration and needle spacing during the second grasping task to determine the degree of change of the second falling trend based on the first adjustment strategy, and collect the second relative displacement difference between the gripper and the fixed plate after the second grasping task is completed based on the second adjustment strategy.

[0048] An adjustment module, which is connected to the reinforcement module and the classification module respectively, is used to adjust the adjustment strategy in response to the second falling trend degree being greater than the first falling trend degree, and to determine the adjustment strategy in response to the comparison result of the second relative displacement difference and the second displacement threshold to perform the third grasping task.

[0049] Compared with existing technologies, this invention selects a corresponding fixed plate based on the total weight of the logistics goods to ensure that the gripping process generates sufficient friction to pick up the goods, while minimizing wear on the robot gripper. By pre-grabbing the logistics goods to determine the location of fragile items inside the packaging box, the fixed plate is adhered to the corresponding box to improve the stability of the robot gripper's gripping of goods. By statistically analyzing the sorting process of the logistics goods, the number of gripping operations is determined in advance, and the total area of ​​the fixed plate is selected based on the total number of fixed needles pierced by the robot gripper in a single operation to improve the efficiency of a single gripping operation and effectively increase the utilization rate of the fixed plate during the gripping task, further improving the accuracy of the control method for the logistics sorting robot gripper.

[0050] Furthermore, this invention also assesses the resistance encountered by the fixed needle during piercing by collecting the driving pressure and driving current of the gripper on the fixed needle during the first grasping task. It analyzes the gripper's gripping strength of the logistics packaging box to further determine if the box is prone to falling. Combining these two factors generates a falling characteristic value, increasing the accuracy of predicting the falling trend of the logistics packaging box during the grasping process. Simultaneously, corresponding reinforcement strategies are implemented promptly for different falling trends to protect fragile items during grasping, ensuring the logistics packaging box is placed stably. After completing the first grasping task, the falling deviation value of the logistics packaging box is calculated. By setting a falling threshold, the degree of center of gravity shift of the logistics packaging box is accurately determined based on the comparison between the deviation value and the threshold, further improving the accuracy of the control method for the logistics sorting robot gripper.

[0051] Furthermore, this invention combines the first relative displacement difference between the gripper and the fixed plate with the degree of center of gravity shift after the first gripping task is completed. Different adjustment strategies are formulated for different situations: significant center of gravity shift but small displacement difference, insignificant center of gravity shift but large displacement difference, and severe center of gravity shift and large displacement difference. This reduces the probability that the adjustment strategy determined by a single parameter is insufficient. By classifying different adjustment strategies, the reliability of the logistics sorting process is ensured, and time for problem solving is saved, further improving the accuracy of the control method for the gripper of the logistics sorting robot.

[0052] Furthermore, this invention also evaluates the actual application effect of the adopted adjustment strategy by determining the detection data for the next grasping task based on each category, collecting the tilt duration and needle spacing of the second grasping for the first adjustment strategy, and comparing them with the data of the first grasping. By comparing the second drop trend degree with the first drop trend degree, it is directly determined whether the adjustment strategy needs to be further updated and optimized. For the second adjustment strategy, the second relative displacement difference after the grasping is completed is collected, and the effectiveness of the adjustment strategy is determined by setting a threshold to determine whether the next grasping task can be carried out. This improves the system's autonomous completion capability and further improves the accuracy of the control method of the gripper of the logistics sorting robot. Attached Figure Description

[0053] Figure 1 This is a flowchart illustrating the control method for the gripper of a logistics sorting robot according to an embodiment of the present invention.

[0054] Figure 2 This is a logic diagram for determining the degree of center of gravity shift of a logistics packaging box according to an embodiment of the present invention;

[0055] Figure 3 This is a logic diagram for determining the degree of change in the second falling trend according to an embodiment of the present invention.

[0056] Figure 4 This is a structural block diagram of the control system of the gripper of the logistics sorting robot according to an embodiment of the present invention;

[0057] Figure 5 This is a schematic diagram of the structure of the gripper of the logistics sorting robot according to an embodiment of the present invention;

[0058] Among them, 1 is the robot; 2 is the fixing plate; 3 is the logistics goods; 4 is the fixing pin; and 5 is the gripper. Detailed Implementation

[0059] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0060] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0061] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0062] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0063] Please see Figure 1 The diagram shown is a flowchart illustrating the control method for a gripper of a logistics sorting robot according to an embodiment of the present invention. The present invention provides a control method for a gripper of a logistics sorting robot, comprising:

[0064] Step S1: Based on the sorting robot's pre-grabbing of logistics goods, determine the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box, and calculate the number of gripping times and the total number of fixing needles pierced by the robot gripper in a single puncture of the logistics goods sorting process.

[0065] Step S2: Determine the area of ​​the fixing plate based on the number of gripping attempts and the total number of pins, and divide the fixing plate into several gripping areas for the first gripping task. Collect the driving pressure of the gripper on the fixing pin and the driving current of the gripper on the fixing pin during the first gripping task to generate a drop characterization value.

[0066] Step S3: Determine the first falling trend of the logistics packaging box based on the falling characterization value and determine the corresponding reinforcement strategy. Calculate the falling deviation value based on the falling characterization value and the first falling threshold to determine the degree of center of gravity shift of the logistics packaging box. Obtain the first relative displacement difference between the gripper and the fixed plate after completing the first grasping task.

[0067] Step S4: Determine the adjustment strategy for the grasping task based on the degree of center of gravity shift and the first relative displacement difference. Classify the adjustment strategies. Based on the first adjustment strategy, collect the tilt duration and needle spacing during the second grasping task to generate trend feature values ​​to determine the degree of change in the second falling trend. Based on the second adjustment strategy, collect the second relative displacement difference between the gripper and the fixed plate after the second grasping task is completed.

[0068] Step S5: In response to the second falling trend being greater than the first falling trend, the adjustment strategy is adjusted. The adjustment strategy is determined based on the comparison result between the second relative displacement difference and the second displacement threshold to perform the third grabbing task.

[0069] It is understood that the entire sorting process of this invention is a multi-cycle iterative control process. The system defines a complete grasping, moving and placing action as a grasping cycle. Based on the comparison of the grasping data of the current cycle and the previous cycle, a corresponding new adjustment strategy is generated to guide the grasping task of the next cycle.

[0070] Specifically, the process of determining the thickness of the fixing plate and its bonding position on the logistics packaging box based on the sorting robot's pre-grabbing of logistics goods includes:

[0071] Based on the results of several pre-grabbing operations, the location of the box body corresponding to the location of the fragile items inside the logistics packaging box is determined as the bonding location.

[0072] The thickness of the corresponding fixing plate is determined by collecting the total weight of the logistics goods.

[0073] Specifically, logistics goods consist of fragile items and logistics packaging boxes.

[0074] It is understandable that fragile items inside logistics packaging boxes need to be fixed in place to prevent breakage during transportation. A robotic gripper picks up the goods and lifts them off the horizontal plane, keeping them suspended in the air. Since the center of gravity of the fragile items inside the packaging box is uncertain, it may cause the packaging box to tilt. After the goods are put down, the position of the fragile items inside the packaging box is determined based on the degree of tilt. The gripping position is adjusted and the gripping is repeated until the goods are lifted into the air and reach a balanced state. The corresponding gripping position is then determined as the bonding position of the fixing plate.

[0075] Understandably, the thickness of the fixing plate must ensure that the fixing pins of the robot gripper can firmly penetrate and prevent the logistics goods from falling, while not piercing the logistics box and damaging fragile items. Therefore, its thickness is mainly related to the total weight that needs to be borne and the strength of the material itself. In practice, the fixing plate is made of medium density fiberboard. When the total weight of the logistics goods is 0-5kg, the thickness of the fixing plate is 10mm.

[0076] When the total weight of the logistics goods is between 5kg and 20kg, the thickness of the fixing plate is 16mm;

[0077] When the total weight of the logistics goods is between 20kg and 50kg, the thickness of the fixing plate is 25mm.

[0078] Specifically, in implementation, the minimum area of ​​a single gripping zone is 15cm², and the number of gripping operations corresponding to the sorting process of logistics goods is 3, so the minimum area of ​​the fixed plate should be 45cm².

[0079] Specifically, this invention selects a corresponding fixed plate based on the total weight of the logistics goods to ensure sufficient friction to lift the goods during the gripping process, while minimizing wear on the robot gripper. By pre-grabbing the logistics goods to determine the location of fragile items inside the packaging box, the fixed plate is adhered to the corresponding box to improve the stability of the robot gripper's gripping of goods. By statistically analyzing the sorting process of the logistics goods, the number of gripping operations is determined in advance, and the total area of ​​the fixed plate is selected based on the total number of fixed needles pierced by the robot gripper in a single operation to improve the efficiency of a single gripping operation and effectively increase the utilization rate of the fixed plate during the gripping task, further improving the accuracy of the control method for the logistics sorting robot gripper.

[0080] Specifically, the process of collecting the driving pressure of the gripper on the fixed pin and the driving current of the gripper on the fixed pin during the first grasping task to generate the drop characterization value includes,

[0081] The ratio of driving pressure to rated driving pressure is determined as the pressure factor.

[0082] The ratio of the drive current to the rated drive current is determined as the current factor;

[0083] The weighted sum of the pressure factor and the current factor is determined to be the drop characterization value.

[0084] Specifically, the rated driving pressure is the average driving pressure of the gripper on the fixed pin when the logistics goods do not tend to fall during historical gripping tasks, and the rated driving current is the average driving pressure of the gripper on the fixed pin when the logistics goods do not tend to fall during historical gripping tasks.

[0085] It is understandable that the sum of the weighting coefficients of the pressure factor and the current factor is 1. Since the driving pressure has a greater impact on the falling trend of logistics goods than the driving current, the weighting coefficient of the pressure factor is generally 0.6 and the weighting coefficient of the current factor is 0.4.

[0086] Specifically, based on drop characteristic values, the degree of the initial drop trend of the logistics packaging box is determined, and the corresponding reinforcement strategy is identified.

[0087] If the drop characterization value is greater than or equal to the first drop threshold, the first drop trend of the logistics packaging box is determined to be a severe drop trend, and the corresponding reinforcement strategy is to increase the number of pins protruding from the gripper drive fixing pin.

[0088] If the drop characterization value is greater than the second drop threshold and less than the first drop threshold, the first drop trend of the logistics packaging box is determined to be a moderate drop trend, and the corresponding reinforcement strategy is to increase the needle spacing of the gripper drive fixing pin.

[0089] If the drop characterization value is less than or equal to the first drop threshold, the first drop trend of the logistics packaging box is determined to be a slight drop trend, and no reinforcement strategy is adopted.

[0090] The first drop threshold is greater than the second drop threshold.

[0091] In a specific embodiment, the first drop threshold is set to 1.05 and the second drop threshold is set to 1.3. If the drop characterization value is greater than the first drop threshold, the first drop trend of the logistics packaging box is determined to be a severe drop trend, and the corresponding reinforcement strategy is to increase the number of pins of the gripper drive fixing pin.

[0092] If the drop characterization value is greater than the second drop threshold and less than the first drop threshold, the first drop trend of the logistics packaging box is determined to be a moderate drop trend, and the corresponding reinforcement strategy is to increase the needle spacing of the gripper drive fixing pin.

[0093] If the drop indicator value is less than the first drop threshold, the first drop trend of the logistics packaging box is determined to be a slight drop trend, and no reinforcement strategy is adopted.

[0094] Understandably, in order to allow sufficient time to implement reinforcement strategies to ensure the safety of fragile items when the grabber detects a tendency for logistics goods to fall, the first drop threshold ranges from 0.95 to 1.15, and the second drop threshold ranges from 1.2 to 1.5.

[0095] Understandably, if the falling trend of the logistics goods is moderate, a reinforcement strategy of increasing the spacing between the pins driven by the gripper is adopted to make the gripper's grasping range larger and reduce the falling trend. If the falling trend of the logistics goods is severe, a reinforcement strategy of increasing the number of pins driven by the gripper is adopted to increase the number of pins that pierce the logistics goods.

[0096] Please see Figure 2 As shown, this is a logic diagram for determining the degree of center of gravity shift of a logistics packaging box according to an embodiment of the present invention. The degree of center of gravity shift of the logistics packaging box is determined by calculating a drop deviation value based on the drop characteristic value and a first drop threshold.

[0097] If the drop deviation value is less than the deviation threshold, the degree of displacement of the center of gravity of the logistics packaging box is determined to be slight.

[0098] If the drop deviation value is greater than or equal to the deviation threshold, the degree of displacement of the center of gravity of the logistics packaging box is determined to be severe displacement.

[0099] Understandably, when determining whether to adjust the strategy for safety assurance, it should first be considered that when the trend of falling logistics goods is predicted, corresponding reinforcement strategies have been taken to ensure safety. Therefore, the first falling threshold and the falling characterization value are used to calculate the falling deviation value.

[0100] Understandably, in order to improve the accuracy of the robot gripper when grasping logistics goods, the deviation threshold is set to a range of 0.05 to 0.15.

[0101] Specifically, this invention also assesses the resistance encountered by the fixed needle during piercing by collecting the driving pressure and driving current of the gripper on the fixed needle during the first gripping task. It analyzes the gripper's gripping strength of the logistics packaging box to further determine if the box is prone to falling. Combining these two factors generates a drop characteristic value, increasing the accuracy of predicting the drop trend of the logistics packaging box during the gripping process. Simultaneously, corresponding reinforcement strategies are implemented promptly for different drop trends to protect fragile items during gripping, ensuring the logistics packaging box is placed stably. After completing the first gripping task, the drop deviation value of the logistics packaging box is calculated. By setting a drop threshold, the degree of center of gravity shift of the logistics packaging box is accurately determined based on the comparison between the deviation value and the threshold, further improving the accuracy of the control method for the logistics sorting robot gripper.

[0102] Specifically, the adjustment strategy for the grasping task is determined based on the degree of center of gravity shift and the first relative displacement difference, wherein,

[0103] If the degree of center of gravity shift is determined to be slight and the first relative displacement difference is less than or equal to the displacement threshold, the adjustment strategy of not performing the grasping task is determined.

[0104] If the degree of center of gravity shift is determined to be slight and the first relative displacement difference is greater than the displacement threshold, the adjustment strategy for the grasping task is determined to be to increase the driving distance of the fixed pin.

[0105] If the degree of center of gravity shift is determined to be severe and the first relative displacement difference is less than or equal to the displacement threshold, the adjustment strategy for the grasping task is to thicken the fixed plate.

[0106] If the center of gravity shift is determined to be severe and the first relative displacement difference is greater than the displacement threshold, the adjustment strategy for the grasping task is to increase the driving distance of the fixed pin and thicken the fixed plate.

[0107] Understandably, when the center of gravity shift is slight and the first relative displacement difference is greater than the displacement threshold, it means the gripper can hold the goods to prevent them from falling, but it cannot prevent them from tilting. Therefore, the adjustment strategy is to replace the fixing pin with a thicker one to increase the piercing area of ​​the fixing pin. When the center of gravity shift is severe and the first relative displacement difference is less than the displacement threshold, it means the fragile object itself is prone to displacement. Therefore, the adjustment strategy is to replace the fixing plate with a larger one to increase the total gripping area of ​​the gripper. When the center of gravity shift is severe and the first relative displacement difference is greater than the displacement threshold, it means the shape of the fragile object may be irregular, which will cause displacement and the control system of the robot gripper is unstable. Therefore, the adjustment strategy is to replace the fixing pin with a longer one and the fixing plate with a thicker one to increase the contact area between the fixing pin and the fixing plate and increase the friction.

[0108] Specifically, the adjustment strategies will be categorized, among which...

[0109] If the adjustment strategy does not replace the fixed plate, the adjustment strategy is classified as the first adjustment strategy.

[0110] If the adjustment strategy involves replacing the fixed plate, then the adjustment strategy is classified as the second adjustment strategy.

[0111] Specifically, this invention further combines the first relative displacement difference between the gripper and the fixed plate with the degree of center of gravity shift after the first gripping task is completed. Different adjustment strategies are formulated for different situations: significant center of gravity shift but small displacement difference, insignificant center of gravity shift but large displacement difference, and severe center of gravity shift and large displacement difference. This reduces the probability that the adjustment strategy determined by a single parameter is insufficient. By classifying different adjustment strategies, the reliability of the logistics sorting process is ensured, and time for problem solving is saved, further improving the accuracy of the control method of the gripper of the logistics sorting robot.

[0112] Specifically, the process of collecting the tilt duration and needle spacing during the second grasping task based on the first adjustment strategy includes:

[0113] The ratio of the first tilt duration to the second tilt duration is calculated as the duration factor;

[0114] The ratio of the first needle exit distance to the second needle exit distance is calculated as the spacing factor;

[0115] The weighted sum of the duration factor and the interval factor is determined to be the trend characteristic value.

[0116] It is understandable that the first tilt duration is the time interval during which the logistics packaging box tilts during the first grasping process, the second tilt duration is the time interval during which the logistics packaging box tilts during the second grasping process, the first needle spacing is the average of the fixed needle spacings during the first grasping process, and the second needle spacing is the average of the fixed needle spacings during the second grasping process.

[0117] Please see Figure 3 As shown, this is a logic diagram for determining the degree of change in the second falling trend according to an embodiment of the present invention. The degree of change in the second falling trend is determined based on trend feature values, wherein...

[0118] If the trend characteristic value is greater than the trend threshold, then the degree of the second falling trend is determined to be less than the degree of the first falling trend.

[0119] If the trend characteristic value is equal to the trend threshold, then the degree of the second falling trend is determined to be equal to the degree of the first falling trend.

[0120] If the trend characteristic value is less than the trend threshold, then the degree of the second falling trend is determined to be greater than the degree of the first falling trend.

[0121] In one specific embodiment, the trend threshold is set to 1. If the trend feature value is greater than 1, it is determined that the degree of the second falling trend is less than the degree of the first falling trend.

[0122] If the trend characteristic value is less than 1, then the degree of the second falling trend is determined to be greater than the degree of the first falling trend.

[0123] It is understandable that when the second tilt duration is greater than the first tilt duration and the second needle spacing is greater than the first needle spacing, it indicates that the friction between the gripper and the fixed plate during the second grasping process is greater than the friction between the gripper and the fixed plate during the first grasping process. The trend threshold is determined by the technicians based on the actual situation. Optionally, the trend threshold ranges from 0.95 to 1.05, and preferably, the trend threshold is 1.

[0124] Specifically, this invention further evaluates the actual application effect of the adopted adjustment strategy by determining the detection data for the next grasping task based on each category, collecting the tilt duration and needle spacing of the second grasping for the first adjustment strategy, and comparing them with the data of the first grasping. By comparing the degree of the second falling trend with the degree of the first falling trend, it is directly determined whether the adjustment strategy needs further updating and optimization. For the second adjustment strategy, the second relative displacement difference after the grasping is completed is collected, and the effectiveness of the adjustment strategy is determined by setting a threshold to determine whether the next grasping task can be carried out. This improves the system's autonomous completion capability and further enhances the accuracy of the control method of the gripper of the logistics sorting robot.

[0125] Specifically, the process of determining the adjustment strategy in response to a second downward trend being stronger than the first downward trend includes:

[0126] The absolute value of the difference between the trend characteristic value and the trend threshold is determined as the trend difference.

[0127] If the trend difference is less than or equal to the trend difference threshold, the adjustment strategy is to thicken the fixed plate.

[0128] If the trend difference is greater than the trend difference threshold, the adjustment strategy is to increase the driving distance of the fixed needle and thicken the fixed plate.

[0129] It is understandable that the trend difference threshold can be determined based on the minimum drop deviation value when the center of gravity of the logistics packaging box is severely displaced. Preferably, the trend difference threshold ranges from 0.15 to 0.35.

[0130] Please see Figure 4 The diagram shown is a structural block diagram of the control system for a logistics sorting robot gripper according to an embodiment of the present invention. The present invention also provides a control system for a logistics sorting robot gripper, comprising:

[0131] The bonding module is used to determine the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box based on the pre-grabbing of logistics goods by the sorting robot, as well as to calculate the number of gripping times and the total number of fixing needles pierced by the robot gripper in a single puncture of the logistics goods sorting process.

[0132] The gripping module, which is connected to the bonding module, is used to determine the area of ​​the fixing plate based on the number of grips and the total number of pins, and to divide the fixing plate into several gripping areas for the first gripping task. It also collects the driving pressure of the gripper on the fixing pin and the driving current of the gripper on the fixing pin during the first gripping task to generate a drop characterization value.

[0133] The reinforcement module, which is connected to the gripping module, is used to determine the first drop trend of the logistics packaging box based on the drop characterization value and to determine the corresponding reinforcement strategy. It also calculates the drop deviation value based on the drop characterization value and the drop threshold to determine the degree of center of gravity displacement of the logistics packaging box and obtains the first relative displacement difference between the gripper and the fixed plate after the first gripping task is completed.

[0134] The classification module, which is connected to the reinforcement module, is used to determine the adjustment strategy of the grasping task based on the degree of center of gravity shift and the first relative displacement difference, classify the adjustment strategy, and generate trend feature values ​​based on the tilt duration and needle spacing during the second grasping task to determine the degree of change of the second falling trend based on the first adjustment strategy. The second relative displacement difference between the gripper and the fixed plate is collected after the second grasping task is completed based on the second adjustment strategy.

[0135] An adjustment module, which is connected to the reinforcement module and the classification module respectively, is used to adjust the adjustment strategy in response to the second falling trend degree being greater than the first falling trend degree, and to determine the adjustment strategy for the third grasping task in response to the comparison result of the second relative displacement difference and the second displacement threshold.

[0136] Please see Figure 5 As shown, it is a structural schematic diagram of the gripper of the logistics sorting robot in an embodiment of the present invention, wherein the robot 1 is connected to the gripper 5; the gripper 5 includes a fixing pin 4; the fixing pin 4 is connected to a fixing plate 2, and the fixing plate 2 is bonded to the logistics goods 3.

[0137] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A control method for a gripper of a logistics sorting robot, characterized in that, include: Based on the pre-grabbing of logistics goods by the sorting robot, the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box are determined. The number of gripping times and the total number of fixing needles pierced by the robot gripper in a single puncture are calculated for the sorting process of logistics goods. The area of ​​the fixing plate is determined based on the number of gripping attempts and the total number of pins, and the fixing plate is divided into several gripping areas for the first gripping task. The driving pressure of the gripper on the fixing pin and the driving current of the gripper on the fixing pin during the first gripping task are collected to generate a drop characterization value. The degree of the first drop trend of the logistics packaging box is determined based on the drop characterization value and the corresponding reinforcement strategy is determined. The drop deviation value is calculated based on the drop characterization value and the first drop threshold to determine the degree of center of gravity displacement of the logistics packaging box. The first relative displacement difference between the gripper and the fixed plate is obtained after the first gripping task is completed. The adjustment strategy for the grasping task is determined based on the degree of center of gravity shift and the first relative displacement difference. The adjustment strategy is classified. Based on the first adjustment strategy, the tilt duration and needle spacing during the second grasping task are collected to generate trend feature values ​​to determine the degree of change of the second falling trend. Based on the second adjustment strategy, the second relative displacement difference between the gripper and the fixed plate is collected after the second grasping task is completed. In response to the second falling trend being greater than the first falling trend, the adjustment strategy is adjusted, and the adjustment strategy is determined in response to the comparison result of the second relative displacement difference and the second displacement threshold to perform the third grabbing task. The process of collecting the driving pressure of the gripper on the fixed pin and the driving current of the gripper on the fixed pin during the first grasping task to generate the drop characterization value includes: The ratio of the driving pressure to the rated driving pressure is determined as the pressure factor. The ratio of the driving current to the rated driving current is determined to be the current factor; The weighted sum of the pressure factor and the current factor is determined to be the drop characterization value; The rated driving pressure is the average driving pressure of the gripper on the fixed pin when the logistics goods do not tend to fall during historical grasping tasks, and the rated driving current is the average driving pressure of the gripper on the fixed pin when the logistics goods do not tend to fall during historical grasping tasks. Based on the drop characterization values, the degree of the initial drop trend of the logistics packaging box is determined, and the corresponding reinforcement strategy is identified. If the drop characterization value is greater than or equal to the first drop threshold, the first drop trend of the logistics packaging box is determined to be a severe drop trend, and the corresponding reinforcement strategy is to increase the number of pins of the gripper drive fixing pin. If the drop characterization value is greater than the second drop threshold and less than the first drop threshold, then the first drop trend of the logistics packaging box is determined to be a moderate drop trend, and the corresponding reinforcement strategy is to increase the needle spacing of the gripper drive fixing needle. The first drop threshold is greater than the second drop threshold.

2. The control method for the gripper of a logistics sorting robot according to claim 1, characterized in that, The process of determining the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box based on the pre-grabbing of logistics goods by the sorting robot includes, Based on the results of several pre-grabbing operations, the location of the box body corresponding to the location of the fragile items inside the logistics packaging box is determined as the bonding location. The thickness of the corresponding fixing plate is determined by collecting the total weight of the logistics goods.

3. The control method for the gripper of a logistics sorting robot according to claim 2, characterized in that, The degree of center-of-gravity shift of the logistics packaging box is determined by calculating the drop deviation value based on the drop characterization value and the first drop threshold. If the drop deviation value is less than the deviation threshold, the degree of displacement of the center of gravity of the logistics packaging box is determined to be slight displacement; If the drop deviation value is greater than or equal to the deviation threshold, the degree of center of gravity displacement of the logistics packaging box is determined to be severe displacement.

4. The control method for the gripper of a logistics sorting robot according to claim 3, characterized in that, The adjustment strategy for the grasping task is determined based on the degree of center of gravity shift and the first relative displacement difference, wherein, If the degree of center of gravity shift is determined to be slight and the first relative displacement difference is less than or equal to the displacement threshold, the adjustment strategy of not performing the grasping task is determined. If the degree of center of gravity shift is determined to be slight and the first relative displacement difference is greater than the displacement threshold, the adjustment strategy for the grasping task is determined to be to increase the driving distance of the fixed pin. If the degree of center of gravity shift is determined to be severe and the first relative displacement difference is less than or equal to the displacement threshold, the adjustment strategy for the grasping task is to thicken the fixing plate. If the degree of center of gravity shift is determined to be severe and the first relative displacement difference is greater than the displacement threshold, the adjustment strategy for the grasping task is determined to be to increase the driving distance of the fixed pin and thicken the fixed plate.

5. The control method for the gripper of a logistics sorting robot according to claim 4, characterized in that, The process of generating trend feature values ​​based on the tilt duration and needle spacing during the second grasping task, using the first adjustment strategy, includes: The ratio of the first tilt duration to the second tilt duration is calculated as the duration factor; The ratio of the first needle exit distance to the second needle exit distance is calculated as the spacing factor; The weighted sum of the duration factor and the interval factor is determined to be the trend characteristic value.

6. The control method for the gripper of a logistics sorting robot according to claim 5, characterized in that, The degree of change in the second falling trend is determined based on trend characteristic values, where... If the trend characteristic value is greater than the trend threshold, then the degree of the second falling trend is determined to be less than the degree of the first falling trend. If the trend characteristic value is less than the trend threshold, then the degree of the second falling trend is determined to be greater than the degree of the first falling trend.

7. The control method for the gripper of a logistics sorting robot according to claim 6, characterized in that, The process of adjusting the adjustment strategy in response to a second falling trend being stronger than the first falling trend includes, The absolute value of the difference between the trend characteristic value and the trend threshold is determined as the trend difference. If the trend difference is less than or equal to the trend difference threshold, then the adjustment strategy is determined to be to thicken the fixing plate. If the trend difference is greater than the trend difference threshold, then the adjustment strategy is determined to be to increase the driving distance of the fixed needle and thicken the fixed plate.

8. A control system for using the control method of the gripper of a logistics sorting robot according to any one of claims 1-7, characterized in that, include, The bonding module is used to determine the thickness of the fixing plate and the bonding position of the fixing plate on the logistics packaging box based on the pre-grabbing of logistics goods by the sorting robot, as well as to calculate the number of gripping times and the total number of fixing needles pierced by the robot gripper in a single puncture of the logistics goods sorting process. The gripping module, which is connected to the bonding module, is used to determine the area of ​​the fixing plate according to the number of gripping and the total number of pins, and to divide the fixing plate into several gripping areas for the first gripping task, and to collect the driving pressure of the gripper on the fixing pin and the driving current of the gripper on the fixing pin during the first gripping task to generate a drop characterization value. The reinforcement module, which is connected to the gripping module, is used to determine the first falling trend of the logistics packaging box based on the falling characterization value and to determine the corresponding reinforcement strategy, and to calculate the falling deviation value based on the falling characterization value and the first falling threshold to determine the degree of center of gravity displacement of the logistics packaging box, and to obtain the first relative displacement difference between the gripper and the fixed plate after the first gripping task is completed. The classification module, which is connected to the reinforcement module, is used to determine the adjustment strategy of the grasping task based on the degree of center of gravity shift and the first relative displacement difference, classify the adjustment strategy, and generate trend feature values ​​based on the tilt duration and needle spacing during the second grasping task to determine the degree of change of the second falling trend based on the first adjustment strategy, and collect the second relative displacement difference between the gripper and the fixed plate after the second grasping task is completed based on the second adjustment strategy. An adjustment module, which is connected to the reinforcement module and the classification module respectively, is used to adjust the adjustment strategy in response to the second falling trend degree being greater than the first falling trend degree, and to determine the adjustment strategy in response to the comparison result of the second relative displacement difference and the second displacement threshold to perform the third grasping task.

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