Dynamic RFID group reading anti-conflict control method and system based on storage mechanical arm and product

Abstract

The invention discloses a dynamic RFID group reading anti-conflict control method and system based on a storage mechanical arm and a product. The method comprises the following steps: constructing a mechanical arm-dynamic RFID integrated system model; in the mechanical arm-dynamic RFID integrated system model, a mechanical arm motion state-anti-conflict linkage mechanism, a dense label priority ranking mechanism and a motion buffer compensation module are designed; and an anti-conflict-motion collaborative optimization target is constructed to optimize the mechanical arm-dynamic RFID integrated system model. Through three core mechanisms of motion state-anti-conflict parameter linkage, label priority ranking and motion buffer compensation, and in combination with mechanical arm dynamics and RFID communication characteristics, RFID group reading with high reading rate and low motion interruption in a dynamic scene is realized, and meanwhile, the timeliness of information acquisition of preferential goods is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of warehousing and logistics technology, specifically to a dynamic RFID group reading anti-collision control method, system, and product based on a warehousing robotic arm. Background Technology

[0002] Collisions in RFID (Radio Frequency Identification) systems are essentially a multiplexing problem, arising from competition and conflicts when multiple tags attempt to communicate with the reader via a shared wireless channel. These collisions lead to identification delays, energy waste, and reduced system throughput. In densely tagged environments, collisions are particularly pronounced, sometimes even causing complete system failure. For details, please refer to Table 1 for an analysis of collision types and characteristics in RFID systems.

[0003] Table 1. Collision Types and Characteristics in RFID Systems

[0004] In addition to the collision types shown in Table 1, RFID systems face a series of unique technical constraints that directly affect the design of anti-collision algorithms: tags need to operate with low power consumption, have limited computing and storage capabilities, limited communication bandwidth, and cannot communicate directly with each other. These limitations prevent many mature anti-collision protocols used in computer networks from being directly applied to RFID systems.

[0005] With the rapid development of intelligent manufacturing, the demand for automation and intelligence in the warehousing and logistics sector is constantly increasing. Robotic arms have been widely used in dynamic operations such as goods sorting and shelf management. Existing warehouse management systems generally rely on RFID technology for tracking and managing items. In warehousing scenarios, robotic arms need to be equipped with RFID readers to read the tags on goods.

[0006] However, in practical applications, the problem of conflicting reads of RFID tags leads to inaccurate data collection, affecting overall logistics efficiency. Furthermore, the dynamic movement of the robotic arm's end effector makes traditional RFID anti-collision methods difficult to adapt. (1) During the movement of the robotic arm, the relative position and distance between the reader and the tag change continuously, and the anti-collision protocol with fixed parameters is prone to tag signal overlap; (2) In the warehouse environment, there are dense labels on goods. Traditional warehouse management mostly relies on manual operation or simple cooperation between robotic arms and RFID systems. The anti-collision method does not distinguish the priority of goods and is prone to invalid collisions. (3) The robotic arm needs to balance motion efficiency and reading accuracy. Existing anti-collision methods will stop moving if a collision is detected, which will lead to a longer work cycle and reduce the efficiency of warehousing work.

[0007] Currently, in the integrated application of robotic arms and RFID, the synergy between trajectory tracking accuracy and RFID reading efficiency is a core requirement. Although some advanced warehouse management systems have automated by introducing RFID and robotic arms, how to effectively avoid reading conflicts and improve reading accuracy in dynamic environments remains a major technical challenge for RFID systems.

[0008] Among the solutions for RFID collision and anti-collision, there are currently RFID anti-collision schemes based on time division multiple access and simple random anti-collision methods for mobile RFID.

[0009] In RFID anti-collision schemes based on time-division multiple access (TDMA), a core challenge for fixed RFID readers is signal conflict when multiple tags respond simultaneously, leading to data reading failures. This scheme addresses this by dividing the time slots into time slices, allowing tags to respond in different time slots, thus avoiding conflicts from a temporal perspective. The scheme supports both "fixed time slot allocation" (for scenarios with a known number of tags) and "dynamic time slot contention" (for scenarios with an unknown number of tags), balancing reading efficiency and compatibility, and is suitable for batch tag identification in fixed scenarios such as warehousing and retail. Specifically, the time slot allocation strategy includes: The system adopts a two-level time structure of "frame-timeslot": the time axis is divided into continuous frames, each frame contains L timeslots, and tags can only send data at the start of a specified timeslot. The reader achieves multiplexing by dynamically adjusting the frame length and timeslot allocation, with each timeslot... It can be in three states—idle, successful, or collision. Based on the above time slot allocation strategy, let's assume that the system... Each tag divides the time frame into 10 tags. Each tag is randomly assigned a time slot.

[0010] Tag assignment probability That is, the probability of each tag responding within a certain time slot is: ; Collision probability That is, the probability of a collision occurring within a certain time slot is:

[0011] The physical layer improvement scheme achieves real-time identification of time slot type through signal strength detection. When a collision is detected, the current time slot can be terminated immediately, reducing invalid waiting time.

[0012] Regarding dynamic frame size adjustment: To improve recognition efficiency, the frame size can be dynamically adjusted based on the recognition status of the current frame. Let the number of tags recognized in the current frame be... The number of unidentified tags is .

[0013] New frame size Adjust the frame size based on the number of unrecognized tags: ; Frame adjustment strategy: If the new frame size differs significantly from the current frame size, the frame size will be adjusted to balance recognition efficiency and system load.

[0014] As can be seen from the above, although the RFID anti-collision scheme based on the time division multiple access method effectively solves the collision problem in high-density tag environments, it also has the following drawbacks: 1. The uncertainty in the number of tags leads to low efficiency in time slot allocation. In practical applications, the number of tags is often dynamic, and the system may encounter situations where the number of tags increases or decreases dramatically during the recognition process. If the number of tags increases, the system needs to reallocate time slots or adjust the frame size, which may lead to performance degradation or uneven system load. The current solution relies on a fixed time slot allocation strategy, with each tag responding within a fixed time slot. This approach may result in low time slot utilization when the number of tags is small, while collisions are prone to occur when the number of tags is large.

[0015] Therefore, during the dynamic adjustment of time slots, it may not be able to respond quickly to changes in the number of tags, leading to recognition delays or inefficiencies. In practical applications, due to the uncertainty of tag response time, fixed time slot allocation may not efficiently utilize resources, resulting in a decline in overall system performance.

[0016] 2. Channel interference caused by retransmission after a collision When a collision occurs, the system needs to wait for the tag to retransmit the signal in the next frame. While the retransmission mechanism can ensure data integrity, it may affect real-time performance in high-density tag environments. Furthermore, RFID systems are significantly affected by the quality of the wireless channel, and channel interference is more likely to occur during retransmission, potentially leading to tag response delays or data loss. Although time-division multiple access (TDMA) methods can effectively avoid collisions within the same time slot, tag responses may still be affected in environments with severe signal interference, resulting in identification failure.

[0017] Therefore, the need for retransmission after a collision increases system latency, especially when there are many tags or the channel environment is poor. An increased collision rate will significantly reduce identification efficiency. Moreover, interference issues will affect the stability and reliability of the RFID system, especially in complex environments, where the system cannot accurately identify tags.

[0018] 3. The complexity of frame size adjustment increases power consumption. Dynamically adjusting frame size can optimize system performance, but this process requires real-time calculations based on tag identification, involving complex algorithms and decision-making processes. Overly frequent or imprecise frame size adjustments may lead to over-adjustment or underutilization of time slots. RFID tags are typically low-power devices, and battery life is a crucial consideration in practical applications. Overly complex time slot scheduling mechanisms or frequent frame size adjustments can increase tag power consumption, reducing the system's continuous operating capability.

[0019] These drawbacks mainly focus on time slot allocation, dynamic changes in the number of tags, collision retransmissions, channel interference, power consumption, and frame size adjustment. These issues limit the efficiency of time division multiple access (TDMA) methods in complex or high-density environments. Therefore, the key to improving this scheme lies in optimizing the time slot allocation mechanism, enhancing dynamic adaptability, reducing collision retransmissions, improving the system's anti-interference capability, and reducing power consumption.

[0020] The core idea of ​​a simple random anti-collision method for mobile RFID is to randomly select a time slot when each tag communicates with the RFID reader, thereby avoiding collisions with responses from other tags. This method does not rely on time slot allocation and a fixed frame structure, but rather avoids collisions by randomly selecting a time slot. The following analysis examines this method from several aspects: tag response mechanism, collision detection and handling, retry mechanism, performance evaluation, and optimization.

[0021] Tag response mechanism: After receiving a query signal from the reader, each tag waits for a random period of time before sending its response signal. Because the random waiting time for each tag is different, the timing of the tag's response also differs, reducing the probability of multi-tag response collisions. Let... T wait Let T be the random time for the tag to wait, which follows a uniform distribution [0, T]. max ],in T max The maximum waiting time is defined as the tag sending a response after the waiting time has elapsed. Strictly speaking, the probability of a response at a single point in time is 0 according to probability theory. However, in RFID anti-collision scenarios, the calculation and analysis of indicators such as collision probability and successful identification probability rely on discrete probability models. Assume the system has... Each tag independently selects a random time to send a signal, in a single extremely short period. Within, the probability of a label response is approximately: Further simplification yields the probability of each tag response per unit time. for: Therefore, the probability of a label selecting a specific time point is uniform.

[0022] Collision Detection and Handling: In collision detection, the system detects a collision when multiple tags respond at the same time. Typically, the reader determines whether a collision has occurred by receiving conflicting response signals. In collision handling, when a collision occurs, all tags involved in the collision will retransmit at a new random time. This process may require multiple attempts until no collisions occur.

[0023] Retry mechanism: Let P be the probability that each label will reselect a time point after each collision. retry According to theoretical analysis, if a collision occurs, the label will have N. retry The number of retries for the label is N, and the process continues until no collision occurs. retry Satisfying collision probability If the label retries follow a geometric distribution, then the expected number of retries is: As the number of tags increases, the probability of collisions increases, and the number of retries also increases. This is expressed as expectation.

[0024] For a mobile RFID system, the response time of a moving tag is closely related to its location. To avoid reduced communication efficiency due to frequent collisions during tag movement, the response time can be optimized in the following ways.

[0025] (1) Dynamically adjust the maximum waiting time: The maximum waiting time of the tag is dynamically adjusted according to the real-time load of the system. T max This allows control over the response probability of the tag.

[0026] (2) Spatial distribution optimization: By rationally designing the location distribution of readers and tags, the possibility of collisions can be reduced. Multiple readers can work in relatively independent areas to avoid signal interference between areas.

[0027] Performance evaluation and optimization in progress: Collision rate The probability of a collision occurring when a tag responds. Based on the response probability of each tag and the total number of tags, the collision rate of the system can be calculated.

[0028] Throughput The number of tags successfully identified per unit of time. Throughput. The probability of successfully recognizing a single, specific tag in a single attempt is related to the tag's response time and success rate. The throughput formula is as follows: ;in, T total It is the total time required to complete one label recognition.

[0029] Recognition time The time required from the start of the system query until all tags are successfully recognized. System recognition time. The decision can be based on the number of retries, the expected waiting time, and the total number of tags. Make an estimate: .

[0030] Therefore, the simple random anti-collision method effectively avoids collision problems that may occur in traditional time slot allocation methods by randomly selecting the tag response time. This scheme does not require a complex time slot allocation mechanism; the tag response relies solely on simple random selection, making it easy to implement. Furthermore, by randomly selecting the time, the probability of tag response collisions is reduced. When the number of tags is small, the system can efficiently utilize idle time slots, improving communication efficiency. However, this scheme has the following problems: 1. Performance degradation As the number of tags increases, the probability of collisions increases, leading to more retries and significantly impacting system throughput and recognition time. Retrying after a collision increases the overall response time, especially with high tag density, where the number of retries and latency continuously increase, affecting the system's real-time performance and efficiency.

[0031] 2. Waste of resources Because the response timing is completely random, the response order of tags cannot be effectively managed, resulting in some tags failing to respond for extended periods or frequent collisions. Even with random time slot selection, multiple tags may respond in adjacent time slots, leading to insufficient channel bandwidth, signal conflicts, and data loss, thus wasting communication resources.

[0032] 3. Energy efficiency and system load Frequent tag time slot selection and retries increase power consumption, especially in mobile RFID systems that require long-term operation. This can lead to rapid battery depletion and affect the system's continuous operation. As the number of tags increases, collisions and retries also increase, requiring the system to handle more communication overhead, resulting in excessive load and a gradual performance decline.

[0033] 4. Lack of intelligence and adaptability This method cannot dynamically adjust time slot allocation or retry mechanism based on the number of tags, channel quality, or environmental changes, resulting in the system being unable to flexibly adapt to changes in complex environments and unable to optimize its performance.

[0034] 5. Real-time issues Delays and retries lead to poor real-time performance: Due to retries after collisions and the randomness of tag response time, the system response time is unstable, especially in large-scale RFID applications, which cannot meet the high requirements for real-time performance. Summary of the Invention

[0035] The technical problem to be solved by this invention is that RFID group reading scenarios are not compatible with the movement of robotic arms.

[0036] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for anti-collision control of dynamic RFID group reading based on warehouse robotic arms includes: Construct a model of a robotic arm-dynamic RFID integrated system; In the robotic arm-dynamic RFID integrated system model, a robotic arm motion state-anti-collision linkage mechanism, a dense tag priority sorting mechanism, and a motion buffer compensation module are designed. Construct an anti-conflict and motion-coordinated optimization objective to optimize the robotic arm-dynamic RFID integrated system model.

[0037] In this embodiment, constructing the robotic arm-dynamic RFID integrated system model includes: Define the motion state vector of the robotic arm end effector RFID reader state vector The state mapping relationship of the robotic arm-dynamic RFID integrated system model is as follows: ; in, The speed of movement at the end effector of the robotic arm. The acceleration at the end effector of the robotic arm. The rotation angle of the robotic arm's end joint, collected by a gyroscope. For matrix transpose, For reading frequency, For the duration of the time slot, For antenna gain, For the mapping parameter matrix, This is the system state mapping function. In this embodiment, the robotic arm motion state-anti-collision linkage mechanism includes: The time slot duration is obtained based on the motion speed of the robotic arm's end effector. : ; Adjusting the antenna gain of the RFID reader based on the rotation angle of the robotic arm's end joint. : ; In the formula, The base time slot is a fixed parameter; This is the reference speed for the robotic arm. Let be the speed of motion at the end effector of the robotic arm, and This speed is within the commonly used speed range for warehouse robotic arms; To avoid compensation terms with a denominator of zero; This refers to the base antenna gain of the RFID reader. Let |θ| be the rotation angle of the end joint of the robotic arm, and |θ|≤60° to avoid unbounded growth of gain.

[0038] In this embodiment, the dense label priority sorting mechanism includes: Build a tag priority list , ;in, This represents the number of tags within the current identification range. "0" indicates a normal priority tag, representing a regular item, while "1" indicates a high priority tag, representing an urgent item. Allocate a dedicated time slot pool for urgent orders with high priority tags, ensuring they are read exclusively and prioritized for time slot access; set a read timeout threshold. And shorten it according to the actual situation of the warehouse to improve the reading efficiency of high priority tags; For ordinary items with ordinary priority tags, allocate the remaining time slot pool and read them sequentially using a first-come, first-served logic; When a high-priority tag conflict occurs: the high-priority tag backs off for a longer period under system control, reducing the conflict waiting time for the high-priority tag.

[0039] In this embodiment, the motion buffer compensation module includes: a conflict detection and buffer triggering mechanism, and stability constraints for buffer compensation; The conflict detection and buffer triggering mechanism is as follows: When the RFID controller detects a high-priority tag conflict, it does not trigger the robotic arm to stop completely. Instead, it sends a buffer command to the robotic arm controller to control the movement state of the robotic arm's end effector and adjust its speed. A buffer time is set during which the RFID reader resends the reading command. After the buffer time ends, the robotic arm returns to its original speed. The stability constraint for buffer compensation is: To prevent goods from tipping over due to sudden braking, the absolute value of acceleration during the buffering process is set to ≤0.1m / s². The stability constraint formula for buffer compensation is then: In the formula, To buffer the actual acceleration of the robotic arm during the compensation process, This represents the maximum acceleration of the robotic arm.

[0040] In this embodiment, the anti-collision-motion cooperative optimization objective is to minimize the collision rate, minimize motion interruption, and maximize the priority tag reading rate. Its objective function expression is: ; In the formula, To optimize the conflict-coordination and motion coordination objective, , , These are the weights for minimizing collision rate, minimizing motion interruption, and maximizing priority tag reading rate, respectively. For tag collision rate, For the interruption time of the robotic arm's movement, For high-priority tag read rate.

[0041] In this embodiment, optimizing the robotic arm-dynamic RFID integrated system model includes: The mapping parameter matrix in the robotic arm-dynamic RFID integrated system model is obtained through gradient descent. To minimize the conflict resistance-motion cooperative optimization objective, the optimization iterative formula is: ; The convergence condition is: Avoid endless iterations and enhance project feasibility; For the first The mapping parameter matrix of the next iteration, For the first The mapping parameter matrix of the next iteration, The learning rate is an adjustable parameter. To optimize the conflict-coordination and motion coordination objective, This is the symbol for gradient descent.

[0042] In this embodiment, the RFID controller transmits the reading result to the host computer database, and at the same time sends a reading success or conflict signal to the robotic arm controller. The host computer updates the inventory status of goods in the host computer database in real time, and tags priority goods as high priority tags and pushes them to the warehouse management system; If the setting is continuous If the second read fails, the robotic arm controller triggers an alarm and records the location of the abnormal label based on the coordinates of the robotic arm's end effector, prompting manual review.

[0043] The present invention also provides a system based on the aforementioned dynamic RFID group reading anti-collision control method for warehouse robotic arms, comprising: The building block is used to construct a model of a robotic arm-dynamic RFID integrated system. The design module is used to design the robotic arm motion state-anti-collision linkage mechanism, dense tag priority sorting mechanism, and motion buffer compensation module in the robotic arm-dynamic RFID integrated system model. The optimization module is used to construct an anti-conflict-motion cooperative optimization objective to optimize the robotic arm-dynamic RFID integrated system model.

[0044] The present invention also provides a computer program product, including a computer program that is executed by a processor to implement the steps of the above-described dynamic RFID group reading anti-collision control method based on warehouse robotic arms.

[0045] Compared with the prior art, the beneficial effects of the present invention are: 1. Improved RFID read rate and inventory visualization accuracy in dynamic scenarios In existing technologies, anti-collision protocols are incompatible with the robotic arm's motion state: existing fixed-parameter anti-collision methods cannot adapt to changes in the robotic arm's speed and acceleration, resulting in high tag collision rates and high missed read rates. This invention, through the linkage of motion state and anti-collision parameters, significantly improves tag reading rates and drastically reduces missed read rates when setting specific robotic arm speeds and rotation angles. Simultaneously, real-time updated RFID reading data improves inventory location accuracy, thereby reducing sorting errors caused by inventory misalignment.

[0046] This invention achieves efficient tag reading in dynamic environments by combining the motion state of a robotic arm with RFID anti-collision parameters. Utilizing real-time motion data from the robotic arm, it automatically adjusts RFID time slot allocation and antenna gain, optimizing the reading process, avoiding collisions, and improving identification efficiency.

[0047] In existing technologies, signal attenuation leads to low read rates: the movement of the robotic arm causes the reader antenna angle to shift, and without real-time compensation for signal gain, the read rate decreases. This invention compensates for signal attenuation caused by the angular shift during robotic arm movement through antenna gain compensation, maintaining a high read success rate.

[0048] 2. The number of interruptions in the movement of the robotic arm has been greatly reduced. In existing technologies, the movement of the robotic arm and RFID reading are not synchronized: when there is a conflict, the robotic arm must stop completely, resulting in low work efficiency and movement jamming. The motion buffer compensation module of this invention avoids complete stops, and the reduction in the number of motion interruptions improves work efficiency and shortens the warehouse sorting cycle.

[0049] 3. Guarantee the timeliness of priority cargo information collection In existing technologies, there is no distinction in label priority: in dense label scenarios, priority goods and ordinary goods are not treated differently, resulting in delays in the collection of priority goods information. The label priority sorting mechanism of this invention reduces the reading delay of high-priority goods, such as some customers' urgent items, making them sorted faster than ordinary goods and avoiding delays in the sorting of priority goods.

[0050] By introducing the concept of tag priority and employing a priority sorting mechanism, the system ensures the timely reading of high-priority goods tags in a high-density tagging environment, improving the efficiency and accuracy of warehousing operations. The system updates inventory information in real time and automatically marks urgent-handling priority goods, ensuring timely response from the warehouse management system.

[0051] 4. Reduce human intervention and hardware dependence Without the need for manual adjustment of RFID parameters or robotic arm motion parameters, the system optimizes anti-collision strategies through online learning, while being compatible with mainstream UHF RFID tags and warehouse robotic arms, thus reducing hardware adaptation costs.

[0052] This invention aims to achieve high read rate and low motion interruption of RFID group reading in dynamic scenarios by combining three core mechanisms: motion state-anti-collision parameter linkage, tag priority sorting, and motion buffer compensation, along with the dynamics of the robotic arm and the communication characteristics of RFID, while ensuring the timeliness of information collection for priority goods.

[0053] Motion buffering and compensation mechanism, closed-loop control, and anomaly handling: When a tag reading conflict occurs, this invention does not completely stop the robotic arm. Instead, it adjusts the robotic arm's motion state through buffering commands to avoid interrupting the work cycle. By dynamically adjusting the speed and compensation time, the loss of work efficiency caused by a complete stop of the robotic arm is reduced. This invention designs a closed-loop control mechanism, with real-time information feedback between the RFID controller and the robotic arm controller via wireless communication to ensure the system's operational stability. Simultaneously, the system can automatically trigger an alarm in the event of consecutive failures, prompting manual review. Attached Figure Description

[0054] Figure 1 This is a flowchart of a dynamic RFID group reading anti-collision control method based on a warehouse robotic arm, according to an embodiment of the present invention.

[0055] Figure 2 This is a schematic diagram of the architecture of the robotic arm-dynamic RFID integrated system model according to an embodiment of the present invention. Detailed Implementation

[0056] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with the accompanying drawings.

[0057] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0058] Please see Figure 1 , 2 As shown, this invention provides a dynamic RFID group reading anti-collision control method based on a warehouse robotic arm, comprising: S10, Construct a robotic arm-dynamic RFID integrated system model.

[0059] In one embodiment of the present invention, the hardware components of the robotic arm-dynamic RFID integrated system model include: Robotic arm module: Employs a multi-degree-of-freedom flexible robotic arm for warehousing, with an end effector equipped with a UHF RFID reader and motion sensors. The "UHF" in UHF RFID reader stands for Ultra High Frequency.

[0060] RFID tag module: Passive UHF tags are attached to cargo pallets, and the tags contain cargo priority identifiers.

[0061] Communication module: It adopts dual-mode communication with Wi-Fi 6 and CAN bus. Wi-Fi 6 enables data interaction between the RFID reader and the host computer, while CAN bus enables synchronization between the robotic arm controller and the RFID controller.

[0062] Construction of the robotic arm-dynamic RFID integrated system model: Define the motion state vector of the robotic arm end effector RFID reader state vector The state mapping relationship of the robotic arm-dynamic RFID integrated system model is as follows: .

[0063] in, The speed of movement at the end effector of the robotic arm. The acceleration at the end effector of the robotic arm. The rotation angle of the robotic arm's end joint, collected by a gyroscope. For matrix transpose, For reading frequency, For the duration of the time slot, For antenna gain, For the mapping parameter matrix, This is the system state mapping function.

[0064] S20, in the robotic arm-dynamic RFID integrated system model, designs a robotic arm motion state-anti-collision linkage mechanism, a dense tag priority sorting mechanism, and a motion buffer compensation module.

[0065] In one embodiment of the invention, the robotic arm motion state-anti-collision linkage mechanism includes: 1. Motion state acquisition: Speed ​​is collected in real time by an encoder at the end of the robotic arm. acceleration The gyroscope collects the joint rotation angle. Sampling period The data is transmitted to the RFID controller via the CAN bus.

[0066] 2. Dynamic time slot allocation The time slot duration is obtained based on the motion speed of the robotic arm's end effector. : ; In the formula, The base time slot is a fixed parameter, more specifically... , The reference speed for the robotic arm is 0.5 m / s in this embodiment. Let be the speed of motion at the end effector of the robotic arm, and This speed is within the commonly used speed range for warehouse robotic arms. To avoid compensation terms with a denominator of zero, based on motion speed. Adjusting the time slot duration The core logic of dynamic time slot allocation is that the faster the speed, the shorter the time slot, so as to avoid overlap of tag signals.

[0067] 3. Adaptive antenna gain compensation Adjusting the antenna gain of the RFID reader based on the rotation angle of the robotic arm's end joint. To compensate for signal attenuation, the specific gain adjustment formula is as follows: ; In the formula, The base antenna gain of the RFID reader is set to 5 dBi in this embodiment, which ensures basic recognition capability without angular offset while reserving sufficient adjustment space for angle compensation gain. The rotation angle of the robotic arm's end joint is given, and |θ|≤60°, ensuring a signal strength ≥-70dBm.

[0068] In one embodiment of the invention, the dense label priority sorting mechanism includes: 1. Tag priority recognition Build a tag priority list , ;in, This represents the number of tags within the current recognition range; "0" indicates a regular priority tag. ), representing a regular item, and "1" is a high-priority tag ( ), which represents an urgent shipment.

[0069] When an RFID reader reads a tag, it prioritizes parsing the priority identifier built into the tag.

[0070] 2. Priority Adjustment Logic In this embodiment of the system, a read timeout threshold is set to determine the maximum waiting time for tag read failures. For high-priority expedited items, shortening the timeout threshold allows the system to identify read anomalies and trigger retries more quickly, preventing expedited items from being delayed due to long waiting times and ensuring their priority processing efficiency. For regular items, the read timeout threshold is set to a relatively long time: a first-come, first-served read logic is used, resulting in a very low probability of conflict; and since their timeliness requirements are lower than expedited items, there is no need to shorten the read timeout threshold. This ensures a high success rate of reading within the remaining time slots while avoiding frequent retries that consume system resources, achieving resource balance and efficiency optimization between high-priority and regular priority tags.

[0071] For urgent requests with high priority tags, allocate a dedicated time slot pool solely for reading high-priority tags, ensuring they occupy time slot resources first and are read preferentially. Set a read timeout threshold. And shorten it according to the actual situation of the warehouse to improve the reading efficiency of high priority tags.

[0072] For ordinary items with ordinary priority tags, allocate the remaining time slot pool and read them sequentially using a first-come, first-served logic.

[0073] For the definitions and explanations of dedicated time slot pools and remaining time slot pools, please refer to Table 2.

[0074] Table 2 Relationship between Time Slot Pool and Time Slot Duration

[0075] In a robotic arm-dynamic RFID integrated system, the management of time slot pools and the setting of time slot durations are key factors in improving system efficiency. A dedicated time slot pool is allocated specifically for high-priority tags, ensuring these tags are read first and avoiding interference from ordinary tags. To ensure rapid data transmission for high-priority tags, the time slot duration in the dedicated pool is shorter, reducing tag waiting time. In contrast, the remaining time slot pool is allocated to ordinary-priority tags. These tags are read on a first-come, first-served basis without priority guarantees; therefore, the time slot duration in the remaining pool is longer to ensure that ordinary tags can also complete data transmission within the specified time.

[0076] The time slot duration determines the duration of each time slot and is closely related to the allocation of the time slot pool. Time slots in the dedicated time slot pool have shorter durations to ensure high-priority tags are read first, avoiding long waiting times. Time slots in the remaining time slot pool have longer durations to ensure that ordinary tags can be read smoothly even without priority. Through reasonable time slot pool allocation and time slot duration settings, the integrated system in this embodiment can balance the reading efficiency of high-priority tags and ordinary tags, ensuring efficient system operation and minimizing tag conflicts and latency.

[0077] Therefore, in a warehousing context, the system in this embodiment can adaptively adjust the resource quotas of the dedicated time slot pool and the remaining time slot pool according to the real-time quantity ratio of expedited and regular items. At the same time, it optimizes the precision of the time slot duration by combining the movement rhythm of the robotic arm. For example, when the robotic arm's handling speed increases, the time slot duration of the two types of time slot pools is shortened simultaneously to ensure that the tag reading always matches the robotic arm's operation rhythm. This dynamic collaborative mechanism enables the entire identification system to achieve a more intelligent balance between efficiency and stability.

[0078] When a high-priority tag conflict occurs: the high-priority tag backs off for a longer period under system control, reducing the conflict waiting time for the high-priority tag.

[0079] When a high-priority tag conflict occurs, the anti-collision-motion cooperative optimization module in this embodiment provides a cooperative strategy that acts on the RFID controller to implement "shortened backoff time" backoff control for the conflicting high-priority tags. This reduces the waiting time of high-priority tags during the conflict, thereby ensuring that these tags can be read as soon as possible without being affected by the reading delay of ordinary tags. At the same time, the RFID controller synchronizes the real-time motion status fed back by the robotic arm controller to ensure that the backoff adjustment and the robotic arm buffer compensation rhythm are adapted to each other. This reduces the waiting time of high-priority tags during the conflict and prevents the robotic arm from stopping completely due to the conflict, ultimately ensuring the reading efficiency of urgent items.

[0080] In this embodiment, since ordinary items are read sequentially according to the first-come-first-served logic, the tag conflict analysis here only focuses on high-priority tag conflicts.

[0081] In one embodiment of the present invention, the motion buffer compensation module includes: a conflict detection and buffer triggering mechanism, and a stability constraint for buffer compensation.

[0082] 1. Conflict detection and buffer triggering mechanism When the RFID controller detects a high-priority tag conflict, it does not trigger a complete stop of the robotic arm. Instead, it sends a buffer command to the robotic arm controller to control the movement of the robotic arm's end effector, reducing the robotic arm speed and extending the time the tag remains within the reader's recognition range. This allows the RFID reader sufficient time to resend the read command, thus avoiding a complete stop of the robotic arm, eliminating significant time and energy consumption during restart, and resolving the tag conflict issue. After the buffer period ends, the robotic arm resumes its original speed, ensuring overall operational efficiency.

[0083] 2. Stability constraints of buffer compensation To prevent goods from tipping over due to sudden braking, the absolute value of acceleration during the buffering process is set to ≤0.1m / s². The stability constraint formula for buffer compensation is then: In the formula, To buffer the actual acceleration of the robotic arm during the compensation process, This represents the maximum acceleration of the robotic arm.

[0084] In this embodiment, the absolute value of acceleration during the buffering process is set based on the robotic arm dynamics model.

[0085] S30, construct an anti-conflict-motion collaborative optimization objective to optimize the robotic arm-dynamic RFID integrated system model.

[0086] In one embodiment of the present invention, the anti-collision-motion cooperative optimization objective is to minimize the collision rate, minimize motion interruption, and maximize the priority tag reading rate, and its formula expression is: ; In the formula, To optimize the conflict-coordination and motion coordination objective, , , These are the weights for minimizing collision rate, minimizing motion interruption, and maximizing priority tag reading rate, respectively. For tag collision rate, For the interruption time of the robotic arm's movement, For high-priority tag read rate.

[0087] In one embodiment of the present invention, the mapping parameter matrix in the robotic arm-dynamic RFID integrated system model is obtained through gradient descent. To minimize the conflict resistance-motion cooperative optimization objective, the optimization iterative formula is: ; The convergence condition is: ; In the formula, For the first The mapping parameter matrix of the next iteration, For the first The mapping parameter matrix of the next iteration, The learning rate is an adjustable parameter; in this embodiment, , To optimize the conflict-coordination and motion coordination objective, This is the symbol for gradient descent.

[0088] In one embodiment of the present invention, an optimized robotic arm-dynamic RFID integrated system model is applied for warehouse management: 1. Closed-loop feedback The RFID controller transmits the reading results to the host computer database, and at the same time sends a reading success or conflict signal to the robotic arm controller.

[0089] In this embodiment, the reading results include tag ID, cargo priority, reading time, etc.

[0090] 2. Inventory data update The host computer updates the inventory status of goods in the host computer database in real time, and tags priority goods as high priority tags and pushes them to the warehouse management system.

[0091] 3. Abnormal Handling If the setting is continuous If the second read fails, the robotic arm controller triggers an alarm and records the location of the abnormal label based on the coordinates of the robotic arm's end effector, prompting manual review.

[0092] In this embodiment, an alarm is triggered after three failed read attempts.

[0093] In another embodiment of the present invention, a system based on the dynamic RFID group reading anti-collision control method for warehouse robotic arms is provided, comprising: The building module is used to construct a model of a robotic arm-dynamic RFID integrated system.

[0094] The design module is used to design the robotic arm motion state-anti-collision linkage mechanism, dense tag priority sorting mechanism, and motion buffer compensation module in the robotic arm-dynamic RFID integrated system model.

[0095] The optimization module is used to construct an anti-conflict-motion cooperative optimization objective to optimize the robotic arm-dynamic RFID integrated system model.

[0096] Furthermore, another embodiment of the present invention provides a computer program product, including a computer program that is executed by a processor to implement the steps of the dynamic RFID group reading anti-collision control method for warehouse robotic arms as described in the above embodiment.

[0097] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0098] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0099] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0100] The above embodiments are merely examples of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for anti-collision control of dynamic RFID group reading based on a warehouse robotic arm, characterized in that, include: Construct a model of a robotic arm-dynamic RFID integrated system; In the robotic arm-dynamic RFID integrated system model, a robotic arm motion state-anti-collision linkage mechanism, a dense tag priority sorting mechanism, and a motion buffer compensation module are designed. Construct an anti-conflict and motion-coordinated optimization objective to optimize the robotic arm-dynamic RFID integrated system model.

2. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, The construction of the robotic arm-dynamic RFID integrated system model includes: Define the motion state vector of the robotic arm end effector RFID reader state vector The state mapping relationship of the robotic arm-dynamic RFID integrated system model is as follows: ; in, The speed of movement at the end effector of the robotic arm. The acceleration at the end effector of the robotic arm. The rotation angle of the robotic arm's end joint, collected by a gyroscope. For matrix transpose, For reading frequency, For the duration of the time slot, For antenna gain, For the mapping parameter matrix, This is the system state mapping function.

3. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, The robotic arm motion state-anti-collision linkage mechanism includes: The time slot duration is obtained based on the motion speed of the robotic arm's end effector. : ； Adjusting the antenna gain of the RFID reader based on the rotation angle of the robotic arm's end joint. : ； In the formula, The base time slot is a fixed parameter. This is the reference speed for the robotic arm. Let be the speed of motion at the end effector of the robotic arm, and This speed is within the commonly used speed range for warehouse robotic arms. To avoid compensation terms with a denominator of zero, This is the base antenna gain for the RFID reader. Let θ be the rotation angle of the end joint of the robotic arm, and |θ|≤60°.

4. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, Dense label priority ranking mechanisms include: Build a tag priority list , ;in, This represents the number of tags within the current identification range. "0" indicates a normal priority tag, representing a regular item, while "1" indicates a high priority tag, representing an urgent item. Allocate a dedicated time slot pool for urgent orders with high priority tags, ensuring they are read exclusively and prioritized for time slot access; set a read timeout threshold. And shorten it according to the actual situation of the warehouse to improve the reading efficiency of high priority tags; For ordinary items with ordinary priority tags, allocate the remaining time slot pool and read them sequentially using a first-come, first-served logic; When a high-priority tag conflict occurs: the high-priority tag backs off for a longer period under system control, reducing the conflict waiting time for the high-priority tag.

5. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, The motion buffering compensation module includes: conflict detection and buffer triggering mechanism, and stability constraints for buffering compensation; The conflict detection and buffer triggering mechanism is as follows: When the RFID controller detects a high-priority tag conflict, it does not trigger the robotic arm to stop completely. Instead, it sends a buffer command to the robotic arm controller to control the movement state of the robotic arm's end effector and adjust its speed. A buffer time is set during which the RFID reader resends the reading command. After the buffer time ends, the robotic arm returns to its original speed. The stability constraint for buffer compensation is: To prevent goods from tipping over due to sudden braking, the absolute value of acceleration during the buffering process is set to ≤0.1m / s². The stability constraint formula for buffer compensation is then: In the formula, To buffer the actual acceleration of the robotic arm during the compensation process, This represents the maximum acceleration of the robotic arm.

6. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, The objectives of the anti-collision-motion cooperative optimization are to minimize the collision rate, minimize motion interruption, and maximize the priority tag reading rate. The formula is as follows: ； In the formula, To optimize the conflict-coordination and motion coordination objectives, , , These are the weights for minimizing collision rate, minimizing motion interruption, and maximizing priority tag reading rate, respectively. For tag collision rate, For the interruption time of the robotic arm's movement, For high-priority tag read rate.

7. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, The optimized robotic arm-dynamic RFID integrated system model includes: The mapping parameter matrix in the robotic arm-dynamic RFID integrated system model is obtained through gradient descent. To minimize the conflict resistance-motion cooperative optimization objective, the optimization iterative formula is: ； The convergence condition is: ; In the formula, For the first The mapping parameter matrix of the next iteration, For the first The mapping parameter matrix of the next iteration, The learning rate is an adjustable parameter. To optimize the conflict-coordination and motion coordination objectives, This is the symbol for gradient descent.

8. The anti-collision control method for dynamic RFID group reading based on warehouse robotic arms according to claim 1, characterized in that, Applying an optimized robotic arm-dynamic RFID integrated system model for warehouse management: The RFID controller transmits the reading results to the host computer database, and at the same time sends a reading success or conflict signal to the robotic arm controller. The host computer updates the inventory status of goods in the host computer database in real time, and tags priority goods as high priority tags and pushes them to the warehouse management system; If the setting is continuous If the second read fails, the robotic arm controller triggers an alarm and records the location of the abnormal label based on the coordinates of the robotic arm's end effector, prompting manual review.

9. A system based on the dynamic RFID group reading anti-collision control method for warehouse robotic arms according to any one of claims 1-8, characterized in that, include: The building block is used to construct a model of the robotic arm-dynamic RFID integrated system. The design module is used to design the robotic arm motion state-anti-collision linkage mechanism, dense tag priority sorting mechanism, and motion buffer compensation module in the robotic arm-dynamic RFID integrated system model. The optimization module is used to construct an anti-conflict-motion cooperative optimization objective to optimize the robotic arm-dynamic RFID integrated system model.

10. A computer program product, comprising a computer program, characterized in that, The computer program is executed by a processor to implement the steps of the dynamic RFID group reading anti-collision control method based on any one of claims 1-8.

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