Batch order picking and sorting method based on maximum irrelevance of goods items

Abstract

The batch order picking and sorting method based on the maximum irrelevance of item items of the present invention. First, divide the N orders to be picked into k batch orders; then, take the two batch orders with the minimum number of the same item items as the first and second batch orders and put them into the set O; next, select the batch order with the minimum "number of the same item items" of the item items contained in the set O as the new batch order and put it into the set O; during the picking process, allocate new batch orders according to the batch order with the minimum "number of the same item items" in the set O until all batch orders are allocated. The batch order picking and sorting method of the present invention calculates the relevance of item items, and as much as possible separates the batch orders with a large number of the same item items, so as to prevent the pickers from entering the same U-shaped picking area location at the same time, reduce the waiting time, and improve the order picking efficiency.

Description

Technical Field

[0001] The present invention relates to a method for sorting batch order picking, and more specifically, to a method for sorting batch order picking based on the maximum irrelevance of item types. Background Art

[0002] In the B2C e-commerce model of production enterprises, it is necessary to pick goods in an e-commerce distribution center with few types of goods and a large number of orders. The picking area usually stores goods in a "U"-shaped channel. As Figure 1 shown, a schematic diagram of the on-site layout of the picking area in the existing e-commerce distribution center is given. The shown picking area adopts a "U"-shaped layout, with best-selling products placed on both outer sides of the "U"-shaped channel and the same layout. The most best-selling products are placed near the entrance of the channel; in the shown picking area, pickers carry a trolley with several turnover boxes for picking. Each turnover box is used to load goods of one variety. Pickers queue up to enter the "U"-shaped channel to pick goods. When the operators responsible for picking two orders go to the same storage location for picking, since the storage locations in the picking area are relatively narrow and only one person is allowed to pick at one storage location, the other person can only wait at this storage location.

[0003] As Figure 2 shown, a flowchart of the picking operation of pickers in the picking area is given. The pickers are only responsible for the picking operation. The system will first merge the orders and print the list of goods required for each order in the batch into a paper picking list and place it in the corresponding trolley. The pickers receive a picking cart with several turnover boxes. The pickers carry the picking cart to the side of the first goods to be picked, and place the corresponding quantity of goods into the turnover boxes according to the goods list. Each turnover box only contains one type of goods and mixing is not allowed. After the picking task of this type of goods is completed, the pickers walk along a fixed path to the next goods to be picked for operation. Until all the goods included in this batch are picked, the pickers send the picking cart to the picked area, and then receive the next batch of picking tasks, and so on in a cycle until all orders are completed.

[0004] Among them, the working time of the pickers in the picking area consists of three parts: a fixed interval time, a picking time, and a waiting time. The fixed interval time refers to the preparation time required by the personnel between picking two batches of orders, and this time is a fixed value; the picking time refers to the time when the personnel pick the goods from the storage location into the trolley, and this time depends on the quantity of goods in the order; the waiting time refers to the time generated by the personnel during the operation due to the occupation of the storage location. The reason for the waiting time is that the same type of goods is included in two adjacent batch orders at the same time, and the operators responsible for picking these two orders go to the same storage location for picking. Since the storage locations in the picking area are relatively narrow and only one person is allowed to pick at one storage location, the other person can only wait at this storage location, so the waiting time is generated.

[0005] It can be seen that among the three parts of the working time, only the size of the waiting time is uncertain. The waiting time is mainly affected by the order sorting factor. If the order of the batch orders is adjusted, and the two adjacent batch orders with waiting time are changed to non - adjacent, the operators picking these two orders will not arrive at the goods location to pick at the same time, thus eliminating the waiting time. Therefore, how to reduce the picking waiting time has become the key to improving the picking efficiency. This article mainly reduces the picking waiting time of the operators through order sorting to improve the goods sorting efficiency. Summary of the Invention

[0006] In order to overcome the shortcomings of the above - mentioned technical problems, the present invention provides a picking and sorting method for batch orders based on the maximum irrelevance of item types of goods.

[0007] The picking and sorting method for batch orders based on the maximum irrelevance of item types of goods of the present invention is characterized in that the batch order picking and sorting method is as follows: First, N orders to be picked are divided into k batch orders according to the quantity of goods that a single picking operator can appropriately pick at one time. A picking operator is responsible for picking the goods in one batch order at a time, and the k batch orders are put into an order pool; then, calculate the number of the same item types of goods contained between every two batch orders in the order pool, and take the two batch orders with the minimum number of the same item types of goods as the first batch order and the second batch order and put them into the set O, and delete the first batch order and the second batch order from the order pool; then, select from the current order pool the batch order with the minimum "number of the same item types of goods" of the item types of goods contained in the set O as the newly selected batch order and put it into the set O, and delete the newly selected batch order from the order pool until the number in the set O reaches the number of picking operators w, and pick the goods according to the principle that one picking operator is responsible for one batch order; during the picking process, when the batch order responsible for a picking operator is picked up, delete the picked - up batch order from the set O, and then select from the current order pool the batch order with the minimum "number of the same item types of goods" of the item types of goods contained in the set O to allocate a new batch order to the picking operator whose batch order has been picked up until all batch orders are allocated.

[0008] The picking and sorting method for batch orders based on the maximum irrelevance of item types of goods of the present invention is specifically realized through the following steps:

[0009] a). Form batch orders; assume the number of orders to be picked is N, and each order contains several item types and the quantity of each item type; limited by the capacity of the trolley and the size of the goods, multiple orders are combined into one batch order according to the quantity of goods that can be appropriately picked by a single picker at one time, and the quantity of goods contained in each batch order is approximately equal; the N orders are divided into k batch orders, and the k batch orders are placed in the order pool; then execute step b);

[0010] b). Obtain the item type correlation of two batch orders; calculate the item types contained in each batch order in the order pool. Assume that in the order pool: the set of item type elements contained in the i-th batch order is q i , and the set of item type elements contained in the j-th batch order is q j ; the set of the same item types of the i-th and j-th batch orders is q i ∩q j , and the number of item types in the set q i ∩q j is |q i ∩q j |. Then, the number of the same item types contained between any two batch orders in the order pool is obtained through formula (1):

[0011] Z ij =|q i ∩q j |; i≠j, i≤k, j≤k (1)

[0012] In the formula, Z ij is the number of the same item types between the i-th and j-th batch orders, and k is the number of original batch orders in the order pool; then execute step c);

[0013] c). Select the initial batch orders; after all pairs of batch orders in the order pool are calculated by formula (1), select the two batch orders corresponding to the minimum Z ij value as the 1st batch order and the 2nd batch order, add them to the set O, the initial value of the set O is an empty set, and delete the 1st batch order and the 2nd batch order added to the set O from the order pool; then execute step d);

[0014] d). Select new batch orders; since the number of pickers w is usually greater than 2, the two batch orders in the set O are not enough for distribution. Calculate the total number Z′ ij of the same item types between the batch order i in the current order pool and the batch orders contained in the set O through formula (2):

[0015]

[0016] In the formula, o j is the set of product item elements contained in the jth batch order in set O, m is the number of current batch orders in set O; v is the batch order that has been screened out in the order pool, and kv represents the remaining batch orders in the current order pool;

[0017] Select the one with the smallest Z′ ij The batch orders in the order pool of the value are added to the collection as new batch orders, and are deleted from the order pool; executing step e);

[0018] e) Supplement set O; determine whether the number of batch orders in set O reaches the number of pickers w. If not, repeat step d) to select batch orders; if equal, assign the w batch orders in set O to w pickers respectively, and the pickers pick the goods in the form of one batch order per person; execute step f);

[0019] f). Update set O; determine whether there is a picker who has finished picking the assigned batch order. If so, delete the batch order that has been picked from set O, then add a new batch order to set O using the same method as in step d), and assign the newly added batch order to the picker who has completed the picking task so that he can continue to pick goods, and execute step g); if not, execute step g);

[0020] g) Determine the remaining batch orders: determine whether the number of remaining batch orders in the current order pool is reduced to equal to the number of pickers w. If it is greater, execute step f); if it is equal, assign the remaining batch orders in the current order pool to the pickers to perform the last batch order picking operation. At this point, all batch orders are picked.

[0021] The beneficial effects of the present invention are as follows: For the batch order picking and sorting method based on the maximum irrelevance of item types of goods in the present invention, first, N orders to be picked are divided into k batch orders. Then, taking the "batch orders" as units, the two batch orders with the least number of "identical item types of goods" are calculated and added to the set O as the 1st and 2nd batch orders. At this time, since the number of identical item types of goods in the 1st and 2nd batch orders is the least, when two pickers simultaneously pick the goods in the 1st and 2nd batch orders, the probability that the two pickers enter the same U-shaped picking area location at the same time is also the smallest. Therefore, the waiting time during the picking of the 1st and 2nd batch orders is minimized to the greatest extent. Among the subsequent batch orders added to the set O, the batch order with the minimum "total quantity of identical item types of goods" with the batch orders in the current set O is selected from the order pool and added, which also ensures that during the simultaneous picking of the batch orders in the current set O, the probability that the pickers enter the same U-shaped picking area location at the same time is the lowest. It can be seen that for the batch order picking and sorting method based on the maximum irrelevance of item types of goods in the present invention, by analyzing and calculating the relevance of item types of goods in the batch orders, the batch orders with a large number of identical item types of goods are separated as much as possible and assigned to different batches for picking, so as to avoid pickers needing to enter the same U-shaped picking area location at the same time, minimizing the picking waiting time to the greatest extent, and thus effectively improving the order picking operation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the on-site layout of the picking area in the existing e-commerce distribution center of the present invention;

[0023] Figure 2 is a flowchart of the operation process of pickers in the picking area of the existing e-commerce distribution center of the present invention;

[0024] Figure 3 is a flowchart of the batch order picking and sorting method based on the maximum irrelevance of item types of goods in the present invention.

[0025] In the figure: 1 floor stacking location, 2 picker, 3 initiation port. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will be further described below in conjunction with the drawings and embodiments.

[0027] As Figure 1As shown in the figure, a schematic diagram of the on-site layout of the picking area of the existing e-commerce distribution center of the present invention is given. The floor stack location 1 in the picking area is arranged in a U shape. The floor stack location 1 is placed on the ground, and the goods to be sold are placed on the floor stack location 1. Only one end of the U-shaped arranged floor stack location 1 can be accessed, and the other end cannot be accessed. Therefore, an initiation port 3 is provided only at one end of the U-shaped picking area. In order to make full use of the storage area, the aisle width of the U-shaped picking area is relatively narrow, usually only allowing one picker to pass through. In this way, if two or more pickers need to pick the goods in the same U-shaped picking area, they need to queue up at the goods location in turn, which increases the picking time of the order. For e-commerce with a large number of orders, the shipping efficiency will be reduced and the cost of picking goods will be increased.

[0028] As Figure 2 As shown in the figure, a flowchart of the operation of pickers in the picking area of the existing e-commerce distribution center of the present invention is given. The pickers are only responsible for the picking operation. The system will first merge the orders and print the list of goods required for each order in the batch into a paper picking detail list and put it into the corresponding trolley. The picker receives a picking cart carrying several turnover boxes. The picker walks with the picking cart to the side of the first goods to be picked, and places the corresponding quantity of goods into the turnover box according to the goods list. Only one type of goods is placed in each turnover box, and mixing is not allowed. After the picking task of this goods is completed, the picker walks to the next goods to be picked along a fixed path for operation. Until all the goods included in this batch are picked, the picker sends the picking cart to the picked area, and then receives the picking task of the next batch, and so on in a cycle until all orders are completed.

[0029] The working time of the pickers in the picking area consists of three parts: fixed interval time, picking time, and waiting time. The waiting time refers to the time generated when the picker is occupied by the goods location during the operation. The reason for the waiting time is that two adjacent batches of orders simultaneously include a certain type of goods. The pickers responsible for picking these two orders go to the same goods location for picking. However, the goods locations in the picking area are relatively narrow, and only one picker is allowed to pick at one goods location, and the other picker can only wait at this goods location, so the waiting time is generated. The waiting time is mainly affected by the order sorting factor. If the order of the batch orders is adjusted, and the two adjacent batches of orders that generate the waiting time are changed to non-adjacent, then the pickers picking these two orders will not arrive at this goods location for picking at the same time, thus eliminating the waiting time.

[0030] The picking and sorting method for batch orders based on the maximum irrelevance of item items of the present invention has the following principle: First, N orders to be picked are divided into k batch orders according to the number of item items that a single picker can appropriately pick at one time. A single picker is responsible for picking the item items in one batch order at a time, and the k batch orders are put into an order pool. Then, calculate the number of the same item items contained between every two batch orders in the order pool. The two batch orders with the minimum number of the same item items are taken as the first batch order and the second batch order and put into the set O, and the first batch order and the second batch order are deleted from the order pool. Next, select from the current order pool the batch order with the minimum "number of the same item items" for the item items contained in the set O as the newly selected batch order and put it into the set O, and delete the newly selected batch order from the order pool until the number in the set O reaches the number w of pickers, and pick the item items according to the principle that one picker is responsible for one batch order. During the picking process, when the batch order responsible for a picker is picked up, delete the picked batch order from the set O, and then select from the current order pool the batch order with the minimum "total number of the same item items" for the batch orders contained in the set O, and allocate a new batch order to the picker who has finished picking until all batch orders are allocated.

[0031] As Figure 3 shown, the flowchart of the picking and sorting method for batch orders based on the maximum irrelevance of item items of the present invention is given, and it is specifically implemented through the following steps:

[0032] a). Form batch orders; assume that the number of orders to be picked is N, and each order contains several item items and the quantity of each item item. Limited by the capacity of the trolley and the size of the item items, multiple orders are combined into one batch order according to the number of item items that a single picker can appropriately pick at one time, and the number of item items contained in each batch order is approximately equal. The N orders are divided into k batch orders, and the k batch orders are put into the order pool; execute step b).

[0033] b). Obtain the relevance of item items between two batch orders; calculate the item items contained in each batch order in the order pool. Assume that in the order pool: the set of item item elements contained in the i-th batch order is q i , and the set of item item elements contained in the j-th batch order is q j ; the set of the same item items of the i-th and j-th batch orders is q i ∩q j , and the number of item items in the set q i ∩q j is |q i ∩q jIf so, the quantity of the same item in two batches of orders in the order pool is calculated by formula (1):

[0034] Z ij = |q i ∩q j |; i≠j, i≤k, j≤k (1)

[0035] In the formula, Z ij is the quantity of the same item in the i-th and j-th batches of orders, and k is the number of original batch orders in the order pool; execute step c);

[0036] c). Select the initial batch orders; after all pairs of batch orders in the order pool are calculated by formula (1), select the two batch orders corresponding to the minimum Z ij value as the 1st batch order and the 2nd batch order, add them to the set O, the initial value of the set O is an empty set, and delete the 1st batch order and the 2nd batch order added to the set O from the order pool; execute step d);

[0037] d). Select new batch orders; since the number w of pickers is usually greater than 2, the two batch orders in the set O are not enough for distribution. Calculate the total quantity Z' of the same item between the batch order i in the current order pool and the batch orders contained in the set O by formula (2) ij :

[0038]

[0039] In the formula, o j is the set of item elements contained in the j-th batch order in the set O, m is the number of current batch orders in the set O; v is the batch order that has been screened out in the order pool, and k - v represents the remaining batch orders in the current order pool;

[0040] Select the batch order in the order pool with the minimum Z' ij value as the new batch order and add it to the set, and delete it from the order pool; execute step e);

[0041] e). Supplement the set O; judge whether the number of batch orders in the set O reaches the number w of pickers. If not, repeat step d) to select batch orders; if equal, distribute the w batch orders in the set O to w pickers respectively, and the pickers pick the goods in the form of one batch order per person; execute step f);

[0042] f). Update set O; determine whether there is a picker who has finished picking the assigned batch order. If so, delete the batch order that has been picked from set O, then add a new batch order to set O using the same method as in step d), and assign the newly added batch order to the picker who has completed the picking task so that he can continue to pick goods, and execute step g); if not, execute step g);

[0043] g) Determine the remaining batch orders: determine whether the number of remaining batch orders in the current order pool is reduced to equal to the number of pickers w. If it is greater, execute step f); if it is equal, assign the remaining batch orders in the current order pool to the pickers to perform the last batch order picking operation. At this point, all batch orders are picked.

[0044] In order to illustrate the optimization effect of the batch order picking and sorting method based on the maximum irrelevance of goods items on order sorting of the present invention, the historical orders of the J e-commerce distribution center were selected for testing. The data set selected the orders during the promotion activity on March 5, 2023. The daily order data volume is more than 5,000 orders, and the number of goods included is about 100. The above data set is tested using two schemes: the first is the time sorting scheme of the J e-commerce distribution center, that is, the orders are batched using a fixed order quantity, and then the batch orders are issued in order of arrival time; the second is the batch order picking and sorting method proposed in this paper, and the total picking time generated by the pickers in the data set under the two schemes is used as the evaluation basis for the optimization effect.

[0045] In order to observe the relationship between the number of pickers and the optimization efficiency, the data set was used for testing when the number of pickers was set to 5 to 20. The picking waiting time and optimization efficiency under the two sorting schemes are shown in Table 1.

[0046] Table 1

[0047]

[0048]

[0049] From the data in the table, we can know the following:

[0050] 1). In the schemes with different numbers of pickers, the batch order picking and sorting method proposed in this paper is better than the original sorting scheme. It can be seen that the batch order picking and sorting method proposed in this paper can effectively reduce the picking waiting time, reduce the picking cost, and improve the picking efficiency.

[0051] 2). As the number of pickers increases, the optimization efficiency shows an upward trend, and the average optimization effect reaches 1.30%. Since additional pickers are required during promotional activities for picking operations, the batch order picking and sorting method proposed in this paper can effectively solve the problem of wasted waiting time caused by the increase in pickers during promotional activities in e-commerce distribution centers, and improve the picking efficiency of e-commerce distribution centers during promotional activities.

[0052] In summary, for the batch order picking and sorting method based on the maximum irrelevance of item types of goods of the present invention, first, the orders of e-commerce of manufacturing enterprises currently show the characteristics of "limited item types of goods, scattered orders, concentrated batches, and huge business volume". A certain number of orders are combined into one batch, and each batch order contains several orders, and several types and quantities of goods are picked, which belongs to the "batch order picking" type. Then, by adjusting the order of issuing each batch order, the item types of goods in the orders picked by each operator are made as non-repetitive as possible within the same time period, so that at most one operator is picking at each storage location, thereby reducing the picking waiting time of the operators as much as possible, which belongs to the "sorting" concept. The sorting method of batch orders is adjusted according to the sum of the quantities of the same item types of goods between each pair of batches. After each batch order is completed, it is deleted from the set O of batch orders being picked, and new orders are added to the set O of batch orders for assignment of personnel for picking, using the "item relevance" concept.

[0053] Therefore, for the batch order picking and sorting method based on item relevance of the present invention, the effects of the optimization solutions in all datasets are better than the original sorting solutions, which shows that the order sorting solution and algorithm designed in the present invention can save the picking waiting time, thereby improving the order picking operation efficiency.

Claims

1. A batch order picking and sorting method based on the maximum irrelevance of goods items, characterized in that, The batch order picking and sorting method is as follows: First, divide the N orders to be picked into k batch orders according to the number of items of goods that a single picker can appropriately pick at one time. A single picker is responsible for picking the goods in one batch order at a time, and put the k batch orders into the order pool. Then, calculate the number of identical item types of goods contained between every two batch orders in the order pool. Take the two batch orders with the minimum number of identical item types of goods as the first batch order and the second batch order and put them into the set O, and delete the first batch order and the second batch order from the order pool. Next, select from the current order pool the batch order with the minimum "number of identical item types of goods" for the item types of goods contained in the set O as the newly selected batch order and put it into the set O, and delete the newly selected batch order from the order pool until the number in the set O reaches the number w of pickers, and pick the goods according to the principle that one picker is responsible for one batch order. During the picking process, when the batch order responsible for a picker is picked, delete the picked batch order from the set O, and then select from the current order pool the batch order with the minimum "total number of identical item types of goods" for the batch orders contained in the set O, and assign a new batch order to the picker whose picking is completed until all batch orders are assigned.

2. The batch order picking and sorting method based on the maximum irrelevance of goods items according to claim 1, wherein Specifically, it is implemented through the following steps: a). Form batch orders; Assume the number of orders to be picked is N, and each order contains several item types of goods and the quantity of each item type of goods. Limited by the capacity of the trolley and the size of the goods, merge multiple orders into one batch order according to the number of items of goods that a single picker can appropriately pick at one time. The quantity of goods contained in each batch order is roughly equal. The N orders are divided into k batch orders, and the k batch orders are put into the order pool. Execute Step b); b). Obtain the relevance of item types of goods between two batch orders; Calculate the items included in each batch of orders in the order pool. Assume that in the order pool, the set of item elements included in the i-th batch of orders is q i , and the set of item elements included in the j-th batch of orders is q j ; the set of items with the same items included in the i-th and j-th batches of orders is q i ∩ q j , and the number of item items in the set q i ∩ q j is |q i ∩ q j |. Then, the number of items with the same items between every two batches of orders in the order pool is obtained through formula (1): Z ij = |q i ∩q j |; i ≠ j, i ≤ k, j ≤ k (1) where Z ij is the quantity of the same item contained between the i-th and j-th batch orders, and k is the number of original batch orders in the order pool; perform step c); c). Select the initial batch orders; after all pairwise batch orders in the order pool are calculated by formula (1), select the two batch orders corresponding to the minimum Z value as the first batch order and the second batch order, add them to set O, the initial value of set O is an empty set, and delete the first batch order and the second batch order added to set O from the order pool; execute step d); ij Value corresponding to the two batch orders as the first batch order and the second batch order, add them to set O, the initial value of set O is an empty set, and delete the first batch order and the second batch order added to set O from the order pool; execute step d); d). Select a new batch of orders; Since the number w of pickers is usually greater than 2, two batches of orders in set O are not sufficient for allocation. Calculate the total quantity Z′ of the same item of goods in batch order i in the current order pool and the batch orders contained in set O through formula (2). ij : Where, o j is the set of item elements of the j-th batch order in the set O, m is the number of current batch orders in the set O; v is the batch order that has been screened out in the order pool, and k - v represents the remaining batch orders in the current order pool; Select the batch order in the order pool with the minimum Z′ ij value as the new batch order and add it to the set, and delete it from the order pool; execute step e); e). Supplement the set O; Judge whether the number of batch orders in the set O reaches the number w of pickers. If not, repeat step d) to select batch orders; If equal, assign the w batch orders in the set O to w pickers respectively, and the pickers pick the goods in the form of one picker for one batch order; Execute step f); f). Update the set O; Judge whether there is a picker whose assigned batch order has been picked. If so, delete the picked batch order from the set O, and then use the same method as in step d) to add a batch order to the set O again and assign the newly added batch order to the picker who has completed the picking task currently so that he can continue to pick the goods, and execute step g); If not, execute step g); g). Judgment of remaining batch orders; judge whether the number of remaining batch orders in the current order pool has decreased to be equal to the number w of pickers. If it is greater, execute step f); if it is equal, allocate the remaining batch orders in the current order pool to the pickers for the picking operation of the last batch of orders. Thus, all batch orders have been picked.

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