A safety interlock control method and system for a stacker

Abstract

The application discloses a safety interlocking control method and system of a stacking machine, and relates to the technical field of interlocking control. The method comprises the following steps: generating a current action end section after a basic interlocking condition is met, determining a receiving observation object according to the current action end section, collecting continuous state changes of the receiving observation object after the current action end section to form a receiving state sequence, and making the system no longer release the next action permission according to the "in position, stop", "retract, wait" discrete signals, but further judging whether the residual influences such as braking inertia, mechanism rebound, cargo table micro-vibration, goods swing or handover support change have been eliminated. Then, the next action permission is controlled according to the action receiving judgment result, the next action is released when the residual influences have been eliminated, and the next action is limited and the receiving protection processing is executed when the residual influences have not been eliminated. Thus, the stretching, walking or handover action can be avoided when the surface interlocking is met but the action receiving state is not stable, and the interference, jamming, deviation and dragging risks are reduced.

Description

Technical Field

[0001] This invention relates to the field of interlock control technology, specifically to a safety interlock control method and system for a stacker crane. Background Technology

[0002] Stacker cranes, as core equipment in automated storage and retrieval systems (AS / RS) for storing, retrieving, handling, and transferring goods, typically need to continuously perform actions such as walking, lifting, fork extension / retraction, picking up and placing goods, and transferring with conveyor lines within the aisles according to scheduling tasks. To prevent stacker cranes from performing actions in unsafe conditions, existing stacker cranes generally employ safety interlock control mechanisms. Before initiating each type of action, the control system collects safety signals such as emergency stop status, safety door status, aisle personnel entry status, walking positioning status, lifting height status, fork retraction status, goods presence / absence status, storage location occupancy status, limit switch status, and drive malfunction status. Corresponding action permission conditions are then established for different actions. For example, stacker crane movement is prohibited when the forks are not fully retracted; fork extension is prohibited when the stacker crane has not stopped precisely at the target storage location; picking and placing goods is prohibited when the loading platform has not reached the target height; and automatic operation is prohibited when the safety door is open or personnel enter the aisle. Therefore, existing safety interlock control can restrict the stacker crane's walking, lifting, fork extension, and loading / unloading processes by requiring both action command and safety permission to be valid before execution, thus preventing obvious safety risks such as malfunctions, overstepping, collisions, personnel intrusion, and incorrect cargo handover.

[0003] However, the aforementioned safety interlock control focuses primarily on whether the discrete safety signals meet preset conditions before the action is initiated. This mainly involves determining whether the stacker crane is "in position," "stopped," "retracted," "cargo present," or "fault-free." However, when the stacker crane continuously performs actions such as high-speed travel braking, high-position lifting and stopping, heavy-load loading and unloading, fork retraction, and conveyor line handover, although the previous action may appear complete on the control signals, the resulting braking inertia, mechanism rebound, platform vibration, cargo swing, pallet friction release, or shelf elastic deformation may not have completely dissipated. At this point, interlock signals such as positioning completion, lifting in place, fork retraction, and normal cargo detection may all appear satisfied, but a stable action handover state has not yet been truly established between the stacker crane, cargo, and storage location. If the system immediately releases permission for the next action, the fork extension, cargo-carrying movement, or handover action may be prematurely executed under seemingly safe but actually unstable dynamic conditions, potentially leading to hidden safety risks such as high-position fork extension interference, pallet jamming, cargo offset, handover dragging, or unstable cargo-carrying operation. Therefore, how to further identify whether the residual effects of the previous action have been safely closed after the existing safety interlock conditions are met remains a problem to be solved in the safety interlock control of stacker cranes. Summary of the Invention

[0004] The purpose of this invention is to solve the problems mentioned in the background art above, and to propose a safety interlock control method and system for stacker cranes.

[0005] A first aspect of the present invention provides a safety interlock control method for a stacker crane, the method comprising:

[0006] S1. After the stacker crane completes the current action and meets the basic interlock conditions, obtain the action end status of the current action and generate the action end section.

[0007] S2. Based on the end section of the current action, determine the receiving observation object corresponding to the current action, and collect the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence.

[0008] S3. Based on the sequence of inherited states, determine whether the residual influence of the current action on the next action has dissipated, and obtain the action inheritance judgment result;

[0009] S4. Control the permission for the next action based on the action acceptance judgment result; when the action acceptance judgment result indicates that the residual effect has dissipated, release the permission for the next action; when the action acceptance judgment result indicates that the residual effect has not dissipated, restrict the permission for the next action and perform the corresponding acceptance protection processing.

[0010] Optionally, after the stacker crane completes the current action and satisfies the basic interlocking conditions, the steps of obtaining the action end state of the current action and generating the action end section include:

[0011] After receiving feedback that the current action has been completed, read the action execution record corresponding to the current action to determine the current action type;

[0012] Based on the current action type, read the stacker crane operating status data and basic interlock feedback data corresponding to the completion time of the current action;

[0013] The stacker crane's operating status data includes stop position, loading platform height position, fork position, loading status, and speed change status. The basic interlock feedback data includes emergency stop status, safety door status, limit status, positioning completion status, lifting and lowering status, fork positioning status, cargo detection status, and drive failure status.

[0014] When the basic interlock feedback data meets the basic interlock conditions corresponding to the current action, the completion time of the current action is determined as the section generation time. Based on the section generation time, the current action type, stacker crane operating status data and basic interlock feedback data are bound together to generate the end section of the current action.

[0015] Optionally, the steps to obtain the successor state sequence are as follows:

[0016] The steps for determining the receiving observation object corresponding to the current action based on the current action's end section, and collecting the continuous state changes of the receiving observation object after the current action ends, to obtain the receiving state sequence include:

[0017] Based on the current action type in the current action end section, determine the corresponding observation object; where the current action is a walking stop action, the observation objects include the walking mechanism, the loading platform, and the goods; the current action is a lifting stop action, the observation objects include the lifting mechanism, the loading platform, and the goods; the current action is a fork extension / retraction action, the observation objects include the fork mechanism, the loading platform, and the goods; when the current action is a picking action, a placing action, or a conveyor line handover action, the observation objects include the goods, the fork mechanism, and the handover position.

[0018] Based on the cargo status in the current action end section, the receiving observation object is modified; when the cargo status is empty, the receiving observation object corresponding to the cargo is deleted; when the cargo status is loaded, the receiving observation object corresponding to the cargo is retained.

[0019] Starting from the moment when the current action ends, the state data of each receiving observation object is collected within the preset observation period according to the preset sampling cycle, and the state data collected at the same sampling moment are combined into receiving state points.

[0020] Multiple acceptance state points are arranged in chronological order of sampling time to obtain the acceptance state sequence.

[0021] Optionally, the steps to determine whether the residual influence of the current action on the next action has dissipated, based on the sequence of succession states, and to obtain the action succession judgment result, are as follows:

[0022] Based on the sequence of receiving states, calculate the closed receiving index and the directional residual index. Add the closed receiving index and the directional residual index to obtain the dissipation index. Compare the dissipation index with the preset dissipation index threshold. Based on the comparison result, determine whether the residual influence of the current action on the next action has dissipated, and obtain the action receiving judgment result.

[0023] Optionally, the steps for calculating the closure index include:

[0024] Read each state point and its state variable in the state sequence, obtain the maximum and minimum values ​​of each state variable among all state points, and perform the same scaling process on each state variable accordingly.

[0025] Calculate the absolute value of the same-scaled numerical difference between any two receiving state points on each of the same state quantities, and take the largest absolute value as the state opening value between the two receiving state points.

[0026] According to the sampling time sequence, any receiving state point to the last receiving state point is determined as a candidate closed tail segment, and the maximum state opening value between any two receiving state points within the candidate closed tail segment is determined as the tail segment opening value.

[0027] The ratio of the number of receiving state points contained in the candidate closed tail segment to the total number of receiving state points is taken as the tail segment proportion. The result of subtracting the tail segment opening value from the tail segment opening value is taken as the tail segment closure value. The tail segment proportion is multiplied by the tail segment closure value to obtain the closure occupancy value.

[0028] The maximum value among all candidate closed tail segments is selected as the continuation closure index.

[0029] Optionally, the steps for calculating the directional residual index include:

[0030] Determine the main motion direction of the current action based on the current action end section, and extract the state coordinates of each receiving observation object in the main motion direction from the receiving state sequence;

[0031] According to the sampling time sequence, calculate the directional displacement of each receiving observation object between two adjacent receiving state points; wherein, the state coordinates of the previous receiving state point are subtracted from the state coordinates of the later receiving state point to obtain the corresponding directional displacement.

[0032] For each adjacent time period, the absolute values ​​of the displacements in each direction within that adjacent time period are added together to obtain the total directional displacement intensity; the absolute value of the sum of the displacements in each direction within that adjacent time period is taken to obtain the directional retention intensity; the directional retention intensity is divided by the total directional displacement intensity to obtain the directional cohesion degree; when the total directional displacement intensity is zero, the directional cohesion degree is determined to be zero.

[0033] Based on the total intensity of the maximum directional displacement in all adjacent time periods, the total intensity of directional displacement in each adjacent time period is normalized to obtain the normalized value of directional displacement intensity. The directional co-convergence degree in the same adjacent time period is multiplied by the normalized value of directional displacement intensity to obtain the directional echo value.

[0034] The directional echo values ​​of adjacent time periods are compared pairwise according to the chronological order. The number of times the directional echo value of the rear direction is greater than the directional echo value of the front direction is counted to obtain the directional re-emergence count. The directional re-emergence count is then divided by the total number of all comparable adjacent time periods to obtain the directional re-emergence rate.

[0035] Subtracting the directional re-emergence rate from 1 yields the directional decay stabilization value. Subtracting the directional echo value from the last adjacent time period from 1 yields the terminal directional deviance value. Multiplying the directional decay stabilization value and the terminal directional deviance value yields the directional residual index.

[0036] Optionally, the steps to determine whether the residual influence of the current action on the next action has dissipated based on the comparison results, and to obtain the action succession judgment result, are as follows:

[0037] When the dissipation index is greater than or equal to the preset dissipation index threshold, it is determined that the residual effect of the current action on the next action has dissipated, and an action succession judgment result representing that the next action can be entered is generated.

[0038] When the dissipation index is less than the preset dissipation index threshold, it is determined that the residual effect of the current action on the next action has not dissipated, and an action succession judgment result is generated that prohibits direct entry into the next action.

[0039] A second aspect of the present invention provides a safety interlock control system for a stacker crane, the system comprising:

[0040] The end section module obtains the action end status of the current action after the stacker crane completes the current action and meets the basic interlock conditions, and generates the current action end section;

[0041] The receiving state module determines the receiving observation object corresponding to the current action based on the current action end section, and collects the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence.

[0042] The judgment result module determines whether the residual influence of the current action on the next action has dissipated based on the sequence of inherited states, and obtains the action inheritance judgment result.

[0043] The control module controls the permission for the next action based on the action acceptance judgment result; when the action acceptance judgment result indicates that the residual effect has dissipated, the permission for the next action is released; when the action acceptance judgment result indicates that the residual effect has not dissipated, the permission for the next action is restricted, and the corresponding acceptance protection processing is performed.

[0044] The beneficial effects of this invention are:

[0045] This invention proposes a safety interlock control method and system for stacker cranes. After the basic interlock conditions are met, the system further generates the current action end section and determines the receiving observation object based on the current action end section. Then, it collects the continuous state changes of the receiving observation object after the current action ends to form a receiving state sequence. This allows the system to no longer directly release the next action permission based solely on discrete safety signals such as "in place," "stop," "retract," "cargo present," or "no fault." Instead, it can further determine whether the residual effects of braking inertia, mechanism rebound, loading platform micro-vibration, cargo swing, pallet friction release, or handover support changes generated after the previous action have dissipated. Based on this, the system forms an action receiving judgment result according to the receiving state sequence and controls the next action permission according to the action receiving judgment result. It can release the next action normally when the residual effects have dissipated, and restrict the next action and perform receiving protection processing when the residual effects have not dissipated. This avoids premature fork extension, cargo movement, or handover actions by the stacker crane when the surface interlock signal is met but a stable action connection has not yet been established between the equipment, goods, and storage location. This reduces hidden safety risks such as high-position fork interference, pallet jamming, cargo offset, handover dragging, and unstable cargo movement, and improves the reliability of safety interlocks during continuous operation of the stacker crane. Attached Figure Description

[0046] Figure 1 This is a flowchart of a safety interlock control method for a stacker crane provided in an embodiment of the present invention. Detailed Implementation

[0047] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0048] This invention provides a safety interlock control method for a stacker crane. See also... Figure 1 , Figure 1 A flowchart illustrating a safety interlock control method for a stacker crane provided in an embodiment of the present invention. The method includes the following steps:

[0049] S1. After the stacker crane completes the current action and meets the basic interlock conditions, obtain the action end status of the current action and generate the action end section.

[0050] S2. Based on the end section of the current action, determine the receiving observation object corresponding to the current action, and collect the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence.

[0051] S3. Based on the sequence of inherited states, determine whether the residual influence of the current action on the next action has dissipated, and obtain the action inheritance judgment result;

[0052] S4. Control the permission for the next action based on the action acceptance judgment result; when the action acceptance judgment result indicates that the residual effect has dissipated, release the permission for the next action; when the action acceptance judgment result indicates that the residual effect has not dissipated, restrict the permission for the next action and perform the corresponding acceptance protection processing.

[0053] In one embodiment, S1, after the stacker crane completes the current action and satisfies the basic interlocking conditions, the step of obtaining the action end state of the current action and generating the action end section is as follows:

[0054] After the stacker crane receives feedback that the current action is completed, it reads the action execution record corresponding to the current action, determines whether the current action belongs to one of the following: walking stop action, lifting stop action, fork extension and retraction action, picking action, putting action, or conveyor line handover action, and uses the determined action category as the current action type.

[0055] Based on the current action type, read the stacker crane operation status data corresponding to the completion time of the current action. The stacker crane operation status data includes at least the stacker crane's stopping position in the aisle direction, the loading platform height position, the fork extension or retraction position, the loading status, and the speed change status before and after the completion time of the current action.

[0056] Read the basic interlock feedback data corresponding to the completion time of the current action. The basic interlock feedback data includes at least the emergency stop status, safety door status, limit status, travel positioning completion status, lifting and lowering status, fork positioning status, cargo detection status, and drive failure status.

[0057] The basic interlock feedback data is matched with the basic interlock conditions corresponding to the current action. When the basic interlock feedback data meets the basic interlock conditions corresponding to the current action, the completion time of the current action is determined as the cross-section generation time.

[0058] Based on the moment of section generation, the current action type, stacker crane operating status data, and basic interlock feedback data are bound together to generate the current action end section, which represents the state of the stacker crane, forks, loading platform, and goods at the end of the current action.

[0059] It should be noted that, after receiving feedback on the completion of the current action, the system first reads the action execution record to determine which of the following actions has just ended: walking stop, lifting stop, fork extension / retraction, picking up, placing, or conveyor line handover. For example, if the action has just completed aisle movement and braking positioning, it is determined to be a walking stop action; if the action has just completed lifting and braking of the loading platform, it is determined to be a lifting stop action. Subsequently, the system reads the corresponding operating status data according to the action type. For example, for a walking stop action, it reads the stop position and speed return status; for a lifting stop action, it reads the loading platform height position; for a fork extension / retraction action, it reads the fork extension or retraction position; and for picking up, placing, or handover actions, it reads the loading status and cargo detection status. After that, it reads basic interlock feedback such as emergency stop, safety door, limit switch, positioning completion, lifting in place, fork in place, cargo detection, and drive failure, and matches it with the basic interlock conditions corresponding to the current action. Only when the action is completed and all basic interlock conditions are met is the completion time of the action determined as the cross-section generation time. Finally, the system uses the moment the cross-section is generated as a reference to bind the current action type, running status data, and basic interlock feedback data to form the current action end cross-section. This cross-section can accurately represent the actual state of the stacker crane, loading platform, forks, and goods at the end of the current action, providing a basis for subsequently determining the objects to be observed.

[0060] In one embodiment, S2, the steps of determining the receiving observation object corresponding to the current action based on the current action end section, and collecting the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence are as follows:

[0061] The steps for determining the receiving observation object corresponding to the current action based on the current action's end section, and collecting the continuous state changes of the receiving observation object after the current action ends, to obtain the receiving state sequence include:

[0062] Based on the current action type in the current action end section, determine the corresponding observation object; where the current action is a walking stop action, the observation objects include the walking mechanism, the loading platform, and the goods; the current action is a lifting stop action, the observation objects include the lifting mechanism, the loading platform, and the goods; the current action is a fork extension / retraction action, the observation objects include the fork mechanism, the loading platform, and the goods; when the current action is a picking action, a placing action, or a conveyor line handover action, the observation objects include the goods, the fork mechanism, and the handover position.

[0063] Based on the cargo status in the current action end section, the receiving observation object is modified; when the cargo status is empty, the receiving observation object corresponding to the cargo is deleted; when the cargo status is loaded, the receiving observation object corresponding to the cargo is retained.

[0064] Starting from the moment when the current action ends, the state data of each receiving observation object is collected within the preset observation period according to the preset sampling cycle, and the state data collected at the same sampling moment are combined into receiving state points.

[0065] Multiple acceptance state points are arranged in chronological order of sampling time to obtain the acceptance state sequence.

[0066] It should be noted that, for example, in a task, the stacker crane has just completed the "carrying and stopping positioning" action. The current action end section generated by S1 records that the current action type is a walking stop action and the loading status is loading. Then, in S2, the system first determines the objects to be observed this time as the walking mechanism, the loading platform, and the goods based on the "walking stop action". This is because the most likely residual effects after walking stops usually come from the braking and stabilization of the walking mechanism, the slight shaking of the loading platform, and the inertial swing of the goods. Subsequently, the system corrects the observed objects based on the loading status in the current action end section. Since the section shows that the stacker crane is currently in a loading state, the goods as the observed object are retained. If the section shows that it is empty, it means that there are no goods that need to be judged for stability after the current action is completed. The system will then delete the goods as the observed object and only retain the walking mechanism and the loading platform. Next, the system uses the moment when the current action ends as the starting point for observation. For example, the moment when the stacker crane completes braking and positioning in front of the tenth column of goods is the starting point for observation. During the subsequent set observation period, the system continuously collects status data at a fixed sampling period. For example, at certain intervals, it simultaneously collects the position stabilization data of the traveling mechanism, the position change data of the loading platform, and the position change data of the goods detection. At each sampling moment, the system merges the data collected at the same moment into a receiving state point. For example, the first receiving state point records "the traveling mechanism still has a slight positional swing, the loading platform has a slight lateral change, and the goods detection position is slightly offset". The second receiving state point records "the position change of the traveling mechanism decreases, the change amplitude of the loading platform decreases, and the goods detection position tends to be stable". The third receiving state point records "the positions of the traveling mechanism, the loading platform, and the goods are basically stable". Finally, the system arranges these acceptance state points in chronological order of sampling time to obtain the acceptance state sequence. This sequence can reflect the continuous change process of the traveling mechanism, loading platform and goods from being affected by braking to gradually stabilizing after the stacker crane has completed its travel and stopped, rather than using only a "travel has stopped" signal to determine whether to proceed to the next action.

[0067] In one embodiment, S3, the step of determining whether the residual influence of the current action on the next action has dissipated based on the succession state sequence, and obtaining the action succession judgment result, is as follows:

[0068] Based on the sequence of receiving states, calculate the closed receiving index and the directional residual index. Add the closed receiving index and the directional residual index to obtain the dissipation index. Compare the dissipation index with the preset dissipation index threshold. Based on the comparison result, determine whether the residual influence of the current action on the next action has dissipated, and obtain the action receiving judgment result.

[0069] In one implementation, the steps for calculating the closure index include:

[0070] Read each state point in the state sequence, determine the multiple state variables contained in each state point, and for each state variable, obtain the maximum and minimum values ​​of that state variable among all state points.

[0071] Based on the maximum and minimum values ​​corresponding to each state variable, the state variable in each receiving state point is subjected to homoscalation. Specifically, the original value of the state variable in the current receiving state point is subtracted from the minimum value of the state variable among all receiving state points, and then divided by the difference between the maximum and minimum values ​​of the state variable among all receiving state points to obtain the homoscalated value of the state variable in the current receiving state point. When the maximum value of the state variable among all receiving state points is equal to the minimum value, the homoscalated value of the state variable in the current receiving state point is determined to be zero.

[0072] Based on the same-scaled values ​​of each state quantity in each receiving state point, calculate the state opening value between any two receiving state points respectively; wherein, for any two receiving state points, calculate the absolute value of the difference between the same-scaled values ​​of the two on the same state quantity, and select the largest absolute value from the absolute values ​​corresponding to all state quantities as the state opening value between the two receiving state points.

[0073] According to the sampling time order of the receiving state sequence, a corresponding candidate closed tail segment is formed from any receiving state point to the last receiving state point. For each candidate closed tail segment, the state opening value between any two receiving state points within the candidate closed tail segment is obtained. The maximum state opening value is selected from the state opening values ​​as the tail segment opening value of the candidate closed tail segment.

[0074] Based on the tail opening value of each candidate closed tail segment and the number of receiving state points contained in the candidate closed tail segment, the closure occupancy value of the candidate closed tail segment is calculated; wherein, the tail segment proportion of the candidate closed tail segment is obtained by dividing the number of receiving state points contained in the candidate closed tail segment by the total number of receiving state points in the receiving state sequence; the tail segment closure value of the candidate closed tail segment is obtained by subtracting the tail opening value of the candidate closed tail segment from the tail opening value; and the closure occupancy value of the candidate closed tail segment is obtained by multiplying the tail segment proportion by the tail segment closure value.

[0075] Select the largest closure occupancy value from all candidate closure tail segments, and determine the largest closure occupancy value as the successor closure index.

[0076] It's important to note that the closure index measures whether the sequence of states following the current action has reached a stable closed state at its end. Essentially, it doesn't simply measure whether a single instantaneous state is normal, but rather whether the continuous state changes of the observed objects—such as the loading platform, cargo, forklift mechanism, traveling mechanism, lifting mechanism, or handover position—after the current action have gradually transitioned from a process of "still changing, still swinging, still rebounding, still releasing residual effects" to a state of "very small changes, sustained state, and no further transmission of influence to the next action." A larger closure index indicates a longer-lasting, smaller-change-internal closed tail segment at the end of the state sequence. In other words, the residual effects after the current action have been confined to a relatively stable range, no longer exhibiting significant further diffusion, repeated fluctuations, or secondary changes. Therefore, a larger dissipation index indicates a greater likelihood that the residual effects of the current action on the next action have dissipated, making it more suitable to release permission for the next action. The reason is that the calculation of this index does not only take the last state point as the judgment, but also looks for the tail segment in the sequence of states that "remains stable from a certain state point to the last state point". The longer this tail segment is, the more likely that the stable state is not a random occurrence, but has been going on for a period of time. The smaller the maximum difference between any two state points within the tail segment, the more likely that the loading platform, goods, forks and other objects have not continued to change significantly during this period of time. For example, after the stacker crane completes its traveling braking, the loading platform may still show slight lateral changes and the cargo detection position may slightly shift in the first three sampling points. However, from the fourth to the last sampling point, the positions of the loading platform, cargo detection, and traveling mechanism remain basically consistent. This indicates that the inertial sway caused by the traveling braking has gradually subsided, and the closure index will be relatively large. In this case, it can be considered that the residual effect has more likely dissipated. Conversely, if the cargo position still shifts repeatedly in the last few sampling points, or if the loading platform stabilizes first and then swings back, the end of the closure state sequence cannot form a reliable closed tail segment, and the closure index will be relatively small. This indicates that the residual effect of the current action may continue to affect the next action. In this case, it is not advisable to directly release the fork extension, traveling with cargo, or handover action permission. In other words, the larger the closure index, the more it indicates that "the state change after the current action has been closed," which corresponds to a smaller residual effect, a higher degree of dissipation, and a greater possibility of the next action being safely accepted.

[0077] In one implementation, the steps for calculating the directional residual index include:

[0078] Determine the main motion direction of the current action based on the current action end section, and extract the state coordinates of each receiving observation object in the main motion direction from the receiving state sequence;

[0079] According to the sampling time sequence, the directional displacement of each receiving observation object between two adjacent receiving state points is calculated respectively; wherein, the state coordinates of the receiving observation object in the main motion direction in the later receiving state point are subtracted from the state coordinates of the receiving observation object in the main motion direction in the previous receiving state point to obtain the directional displacement of the receiving observation object in the adjacent time period.

[0080] For each adjacent time period, the absolute values ​​of the directional displacements of all objects under observation within that adjacent time period are taken and then summed to obtain the total directional displacement intensity of that adjacent time period; and the absolute values ​​of the directional displacements of all objects under observation within that adjacent time period are directly summed to obtain the directional retention intensity of that adjacent time period.

[0081] Based on the total directional displacement intensity and the directional retention intensity, the directional co-cohesion degree of the adjacent time period is calculated; wherein, when the total directional displacement intensity is not zero, the directional retention intensity is divided by the total directional displacement intensity to obtain the directional co-cohesion degree of the adjacent time period; when the total directional displacement intensity is zero, the directional co-cohesion degree of the adjacent time period is determined to be zero;

[0082] The maximum total directional displacement intensity is selected from the total directional displacement intensity of all adjacent time periods, and the total directional displacement intensity of each adjacent time period is normalized based on the maximum total directional displacement intensity. Specifically, when the maximum total directional displacement intensity is not zero, the total directional displacement intensity of each adjacent time period is divided by the maximum total directional displacement intensity to obtain the normalized value of the directional displacement intensity of the corresponding adjacent time period; when the maximum total directional displacement intensity is zero, the normalized value of the directional displacement intensity of each adjacent time period is set to zero.

[0083] For each adjacent time period, the directional co-convergence degree of the adjacent time period is multiplied by the normalized value of the directional displacement intensity of the adjacent time period to obtain the directional echo value of the adjacent time period.

[0084] According to the chronological order, the directional echo values ​​of all adjacent time periods are compared pairwise, and the number of times the directional echo value of the adjacent time period that is later is greater than the directional echo value of the adjacent time period that is earlier is counted as the directional re-emergence count.

[0085] The direction re-emphasis rate is calculated based on the number of direction re-emphasis events. Specifically, the direction re-emphasis rate is obtained by dividing the number of direction re-emphasis events by the total number of comparable adjacent time periods. The total number of comparable adjacent time periods is calculated by multiplying the total number of adjacent time periods by one and then dividing by two.

[0086] Subtract the directional re-emergence rate from 1 to obtain the directional decay stabilization value; subtract the directional echo value of the last adjacent time period from 1 to obtain the terminal directional deviance value; multiply the directional decay stabilization value and the terminal directional deviance value to obtain the directional residual index.

[0087] It's important to note that the directional residual index measures whether the directional influence of the previous action remains in the subsequent state sequence after the current action ends. Specifically, it determines whether residual effects such as inertia, rebound, swaying, or dragging continue to manifest along the original action direction. A larger directional residual index indicates a weaker directional trace of the previous action, meaning the changes in the observed object no longer concentrate along the original direction of motion, and no re-enhancement of directional echoes in subsequent periods. Therefore, a larger dissipation index indicates a greater likelihood that the residual influence of the current action on the next action has dissipated. This is because the most likely influence on the next action from the previous action is not ordinary, minor fluctuations, but rather residual changes with a clear direction. For example, the forward and backward swaying after braking affects fork alignment, the up and down rebound after lifting stops affects the loading and unloading height, and the directional dragging after fork retraction affects cargo stability. If these directional changes have weakened and disappeared at the end, it means the residual influence is no longer transmitted to the next action; if they still repeatedly appear along the original direction, it indicates the current action has not yet stabilized, and it is not advisable to directly release permission for the next action.

[0088] In one embodiment, the steps for comparing the dissipation index with a preset dissipation index threshold and determining whether the residual influence of the current action on the next action has dissipated based on the comparison result to obtain the action succession judgment result are as follows:

[0089] When the dissipation index is greater than or equal to the preset dissipation index threshold, it is determined that the residual effect of the current action on the next action has dissipated, and an action succession judgment result representing that the next action can be entered is generated.

[0090] When the dissipation index is less than the preset dissipation index threshold, it is determined that the residual effect of the current action on the next action has not dissipated, and an action succession judgment result is generated that prohibits direct entry into the next action.

[0091] The action acceptance judgment result is sent to the stacker crane's action authorization control unit, so that the action authorization control unit can control the next action authorization based on the action acceptance judgment result.

[0092] It should be noted that the purpose of this step is to convert the previously calculated dissipation index into a judgment result that can directly control the next action of the stacker crane. In other words, it transforms "whether the residual effect is small enough" into a clear "allowing to proceed to the next action" or "prohibiting direct entry into the next action". Specifically, the dissipation index is derived from the closure index and the directional residue index. The larger the value, the more stable the state after the current action, the weaker the directional residue of the previous action, and the smaller the impact on the next action. Therefore, the system compares the dissipation index with a preset dissipation index threshold. When the dissipation index is greater than or equal to the preset dissipation index threshold, it means that the loading platform, goods, fork mechanism, or handover position after the current action has basically completed stable closure, and the residual effects of braking inertia, mechanism rebound, goods swinging back, or handover drag generated by the current action have been reduced to an acceptable range. The system then generates an action closure judgment result of "allowing entry into the next action" and sends it to the action permission control unit, which releases the permission for the next action if the basic interlock conditions are also met. When the dissipation index is less than the preset dissipation index threshold, it means that the closure state after the current action has not yet been stably closed, or there is still a significant directional residue. The impact of the previous action may still be transmitted to the next action. The system then generates an action closure judgment result of "prohibiting direct entry into the next action," causing the action permission control unit to temporarily not release the permission for the next action. For example, after a stacker crane completes its journey with cargo and stops, if the dissipation index reaches a preset threshold, it indicates that the swaying of the loading platform and the swaying of the cargo after braking have largely dissipated, allowing subsequent fork extension or lifting actions. If the dissipation index is below the threshold, it indicates that the cargo may still slightly deviate along the direction of travel or the loading platform is not yet stable. In this case, even if the basic interlock signals such as travel positioning, fork retraction, and cargo detection are normal, fork extension or high-speed travel is not directly permitted. The advantage of this is that the permission for the next action no longer depends solely on discrete interlock signals such as "positioning, stopping, and retraction," but is further constrained by the stability of the action. This avoids the stacker crane prematurely executing the next action when the surface interlock is satisfied but the dynamic residue has not yet dissipated, thereby reducing hidden risks such as high-level fork extension interference, pallet jamming, cargo deviation, and handover dragging.

[0093] In one embodiment, S4, controlling the permission for the next action based on the action acceptance judgment result; when the action acceptance judgment result indicates that the residual effect has dissipated, releasing the permission for the next action; when the action acceptance judgment result indicates that the residual effect has not dissipated, restricting the permission for the next action and performing the corresponding acceptance protection processing specifically:

[0094] The steps of controlling the permission for the next action based on the action acceptance judgment result include: releasing the permission for the next action when the action acceptance judgment result indicates that the residual effect has dissipated; and restricting the permission for the next action and performing the corresponding acceptance protection processing when the action acceptance judgment result indicates that the residual effect has not dissipated.

[0095] The action is read to determine the result of the judgment, and the next action to be executed is determined according to the task execution order of the stacker crane;

[0096] When the action acceptance judgment result indicates that the residual effect has dissipated, the basic interlock condition corresponding to the next action is read, and when the basic interlock condition corresponding to the next action is satisfied, the action permission signal is output to the drive control unit corresponding to the next action.

[0097] When the action acceptance judgment result indicates that the residual effect has not dissipated, the output of the action permission signal to the drive control unit corresponding to the next action is prohibited, and the acceptance protection mode is determined according to the action type of the next action.

[0098] When the next action is the fork extension action, the protection mode is set to keep the stacker crane and loading platform stationary, and the continuous state changes of the observation object are collected again.

[0099] When the next action is a walking action, the protection mode will be set to prohibit high-speed walking, and low-speed inching reset will be allowed until the residual effects have been reassessed and dissipated.

[0100] When the next action is a lifting action, the protection mode will be set to keep the lifting mechanism in a braking state, and the height of the loading platform and the status of the goods will be reconfirmed.

[0101] When the next action is a picking action, a placing action, or a conveyor line handover action, the receiving protection mode will be determined to suspend the picking, placing, or handover process, and the cargo support status and handover position status will be reconfirmed.

[0102] After executing the protection mode, the protection state sequence is regenerated, and the residual effect of the current action on the next action is determined again based on the regenerated protection state sequence.

[0103] If the result of the second assessment indicates that the residual effect has dissipated, the permission for the next action is released; if the result of the second assessment still indicates that the residual effect has not dissipated, the permission for the next action continues to be restricted, and an exception prompt is generated.

[0104] It's important to note that the core of this step is to truly transform the "action acceptance judgment result" obtained in the previous step into permission control for the next action of the stacker crane, rather than simply generating a judgment flag. Specifically, the system first reads the action acceptance judgment result and determines the next action to be executed in conjunction with the current task flow. For example, the next action might be fork extension, movement, lifting, picking up, placing, or conveyor line handover. If the action acceptance judgment result indicates that the residual effects have dissipated, it means that the micro-vibration of the loading platform, cargo swing, mechanism rebound, or changes in handover support after the current action has been judged to no longer affect the next action. At this point, the system still will not directly start the next action, but will continue to read the basic interlock conditions corresponding to the next action itself. Only when the basic interlock conditions of the next action are also met will the system output an action permission signal to the corresponding drive control unit. For example, when preparing to execute the fork extension action, it is also necessary to confirm that the stacker crane positioning is complete, the lifting height is in place, the initial position of the forks is normal, and the target cargo position status meets the requirements. Conversely, if the action acceptance judgment result indicates that the residual effect has not dissipated, the system prohibits the output of action permission signal to the drive control unit corresponding to the next action, and adopts different acceptance protection methods according to the type of the next action: If the next action is a fork extension action, it means that it is most necessary to avoid the forks from extending into the storage position before the loading platform or goods are stable. Therefore, the stacker crane and loading platform are kept stationary, and the continuous state changes of the observation object are re-acquired; if the next action is a walking action, it means that it is necessary to avoid the goods from entering high-speed movement when they are not stably loaded. Therefore, high-speed walking is prohibited, and low-speed inching reset is only allowed when necessary; if the next action is a lifting action, the lifting mechanism is kept in braking state, and the loading platform height and goods status are reconfirmed to prevent further amplification of goods offset or loading platform fluctuation during lifting; if the next action is a picking, placing, or conveyor line handover action, the corresponding process is paused, and the goods support status and handover position status are reconfirmed to avoid half-support, dragging, or incomplete handover. For example, after the stacker crane stops carrying goods, if the system determines that the residual effects have not dissipated and the next action is to extend the forks, even if the traditional interlock conditions such as positioning completion, fork retraction, and storage permission are all normal, the system will not immediately extend the forks. Instead, it will first keep the equipment stationary and re-observe whether the loading platform and goods are stable. If the regenerated acceptance status sequence shows that the residual effects have dissipated, the fork extension permission will be released. If the effects have not dissipated, the next action will continue to be restricted and an acceptance anomaly prompt will be generated.The advantage of this approach is that the permission for the next action is no longer simply "execution upon fulfillment of basic interlocks," but rather a two-layer control logic of "basic interlock conditions plus action continuity stability." This ensures normal operational efficiency when residual effects have dissipated, while also allowing for differentiated protection measures for different next actions when residual effects have not yet dissipated. This avoids coarse control caused by uniform shutdowns or simple delays, and also reduces hidden risks such as interference from high-position forks, deviation during cargo movement, amplified shaking during lifting and lowering, jamming during cargo handling, and dragging during conveyor line handover.

[0105] Based on the same inventive concept, this invention also provides a safety interlock control system for a stacker crane, including:

[0106] The end section module obtains the action end status of the current action after the stacker crane completes the current action and meets the basic interlock conditions, and generates the current action end section;

[0107] The receiving state module determines the receiving observation object corresponding to the current action based on the current action end section, and collects the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence.

[0108] The judgment result module determines whether the residual influence of the current action on the next action has dissipated based on the sequence of inherited states, and obtains the action inheritance judgment result.

[0109] The control module controls the permission for the next action based on the action acceptance judgment result; when the action acceptance judgment result indicates that the residual effect has dissipated, the permission for the next action is released; when the action acceptance judgment result indicates that the residual effect has not dissipated, the permission for the next action is restricted, and the corresponding acceptance protection processing is performed.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A safety interlock control method for a stacker crane, characterized in that, Includes the following steps: S1. After the stacker crane completes the current action and meets the basic interlock conditions, obtain the action end status of the current action and generate the action end section. S2. Based on the end section of the current action, determine the receiving observation object corresponding to the current action, and collect the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence. S3. Based on the sequence of inherited states, determine whether the residual influence of the current action on the next action has dissipated, and obtain the action inheritance judgment result; S4. Based on the action continuation judgment result, control the permission of the next action; When the action acceptance judgment result indicates that the residual effect has dissipated, the permission for the next action is released; when the action acceptance judgment result indicates that the residual effect has not dissipated, the permission for the next action is restricted, and the corresponding acceptance protection processing is performed.

2. The safety interlock control method for a stacker crane according to claim 1, characterized in that, After the stacker crane completes its current action and satisfies the basic interlock conditions, the steps to obtain the action completion status of the current action and generate the action completion section include: After receiving feedback that the current action has been completed, read the action execution record corresponding to the current action to determine the current action type; Based on the current action type, read the stacker crane operating status data and basic interlock feedback data corresponding to the completion time of the current action; The stacker crane's operating status data includes stop position, loading platform height position, fork position, loading status, and speed change status. The basic interlock feedback data includes emergency stop status, safety door status, limit status, positioning completion status, lifting and lowering status, fork positioning status, cargo detection status, and drive failure status. When the basic interlock feedback data meets the basic interlock conditions corresponding to the current action, the completion time of the current action is determined as the section generation time. Based on the section generation time, the current action type, stacker crane operating status data and basic interlock feedback data are bound together to generate the end section of the current action.

3. The safety interlock control method for a stacker crane according to claim 1, characterized in that, The steps to obtain the successor state sequence are as follows: The steps for determining the receiving observation object corresponding to the current action based on the current action's end section, and collecting the continuous state changes of the receiving observation object after the current action ends, to obtain the receiving state sequence include: Based on the current action type in the current action end section, determine the corresponding observation object; where the current action is a walking stop action, the observation objects include the walking mechanism, the loading platform, and the goods; the current action is a lifting stop action, the observation objects include the lifting mechanism, the loading platform, and the goods; the current action is a fork extension / retraction action, the observation objects include the fork mechanism, the loading platform, and the goods; when the current action is a picking action, a placing action, or a conveyor line handover action, the observation objects include the goods, the fork mechanism, and the handover position. Based on the cargo status in the current action end section, the receiving observation object is modified; when the cargo status is empty, the receiving observation object corresponding to the cargo is deleted; when the cargo status is loaded, the receiving observation object corresponding to the cargo is retained. Starting from the moment when the current action ends, the state data of each receiving observation object is collected within the preset observation period according to the preset sampling cycle, and the state data collected at the same sampling moment are combined into receiving state points. Multiple acceptance state points are arranged in chronological order of sampling time to obtain the acceptance state sequence.

4. The safety interlock control method for a stacker crane according to claim 1, characterized in that, Based on the sequence of succession states, the steps to determine whether the residual influence of the current action on the next action has dissipated, and to obtain the action succession judgment result, are as follows: Based on the sequence of receiving states, calculate the closed receiving index and the directional residual index. Add the closed receiving index and the directional residual index to obtain the dissipation index. Compare the dissipation index with the preset dissipation index threshold. Based on the comparison result, determine whether the residual influence of the current action on the next action has dissipated, and obtain the action receiving judgment result.

5. The safety interlock control method for a stacker crane according to claim 4, characterized in that, The steps for calculating the closure index include: Read each state point and its state variable in the state sequence, obtain the maximum and minimum values ​​of each state variable among all state points, and perform the same scaling process on each state variable accordingly. Calculate the absolute value of the same-scaled numerical difference between any two receiving state points on each of the same state quantities, and take the largest absolute value as the state opening value between the two receiving state points. According to the sampling time sequence, any receiving state point to the last receiving state point is determined as a candidate closed tail segment, and the maximum state opening value between any two receiving state points within the candidate closed tail segment is determined as the tail segment opening value. The ratio of the number of receiving state points contained in the candidate closed tail segment to the total number of receiving state points is taken as the tail segment proportion. The result of subtracting the tail segment opening value from the tail segment opening value is taken as the tail segment closure value. The tail segment proportion is multiplied by the tail segment closure value to obtain the closure occupancy value. The maximum value among all candidate closed tail segments is selected as the continuation closure index.

6. The safety interlock control method for a stacker crane according to claim 4, characterized in that, The steps for calculating the directional residual index include: Determine the main motion direction of the current action based on the current action end section, and extract the state coordinates of each receiving observation object in the main motion direction from the receiving state sequence; According to the sampling time sequence, calculate the directional displacement of each receiving observation object between two adjacent receiving state points; wherein, the state coordinates of the previous receiving state point are subtracted from the state coordinates of the later receiving state point to obtain the corresponding directional displacement. For each adjacent time period, the absolute values ​​of the displacements in each direction within that adjacent time period are added together to obtain the total directional displacement intensity; the absolute value of the sum of the displacements in each direction within that adjacent time period is taken to obtain the directional retention intensity; the directional retention intensity is divided by the total directional displacement intensity to obtain the directional cohesion degree; when the total directional displacement intensity is zero, the directional cohesion degree is determined to be zero. Based on the total intensity of the maximum directional displacement in all adjacent time periods, the total intensity of directional displacement in each adjacent time period is normalized to obtain the normalized value of directional displacement intensity. The directional co-convergence degree in the same adjacent time period is multiplied by the normalized value of directional displacement intensity to obtain the directional echo value. The directional echo values ​​of adjacent time periods are compared pairwise according to the chronological order. The number of times the directional echo value of the rear direction is greater than the directional echo value of the front direction is counted to obtain the directional re-emergence count. The directional re-emergence count is then divided by the total number of all comparable adjacent time periods to obtain the directional re-emergence rate. Subtracting the directional re-emergence rate from 1 yields the directional decay stabilization value. Subtracting the directional echo value from the last adjacent time period from 1 yields the terminal directional deviance value. Multiplying the directional decay stabilization value and the terminal directional deviance value yields the directional residual index.

7. The safety interlock control method for a stacker crane according to claim 4, characterized in that, The steps to determine whether the residual effect of the current action on the next action has dissipated based on the comparison results, and to obtain the action succession judgment result, are as follows: When the dissipation index is greater than or equal to the preset dissipation index threshold, it is determined that the residual effect of the current action on the next action has dissipated, and an action succession judgment result representing that the next action can be entered is generated. When the dissipation index is less than the preset dissipation index threshold, it is determined that the residual effect of the current action on the next action has not dissipated, and an action succession judgment result is generated that prohibits direct entry into the next action.

8. A safety interlock control system for a stacker crane, used to implement the safety interlock control method for a stacker crane as described in any one of claims 1-7, characterized in that, The system includes: The end section module obtains the action end status of the current action after the stacker crane completes the current action and meets the basic interlock conditions, and generates the current action end section; The receiving state module determines the receiving observation object corresponding to the current action based on the current action end section, and collects the continuous state changes of the receiving observation object after the current action ends to obtain the receiving state sequence. The judgment result module determines whether the residual influence of the current action on the next action has dissipated based on the sequence of inherited states, and obtains the action inheritance judgment result. The control module controls the permission for the next action based on the action acceptance judgment result; when the action acceptance judgment result indicates that the residual effect has dissipated, the permission for the next action is released; when the action acceptance judgment result indicates that the residual effect has not dissipated, the permission for the next action is restricted, and the corresponding acceptance protection processing is performed.

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