Zigbee-based dyeing plant cloth vehicle positioning system and method

Abstract

The invention relates to a zigbee-based dyeing plant cloth vehicle positioning system and method, and the system comprises a sensing layer which comprises a plurality of positioning tags, the positioning tags are disposed on a dyeing plant cloth vehicle, and each positioning tag comprises an IMU sensor module, a zigbee communication module and a battery system; the network layer is used for data transmission between the sensing layer and the platform layer; the platform layer is used for obtaining the relative displacement and the course angle of the cloth vehicle of the dyeing plant according to the pose data when the position of the cloth vehicle of the dyeing plant changes, obtaining the absolute position of the cloth vehicle of the dyeing plant according to the zigbee positioning signal, and fusing the calculated relative displacement and absolute position to obtain the positioning result of the cloth vehicle of the dyeing plant; and the application layer is used for visually displaying the positioning result. The IMU sensor module is combined with the zigbee communication module to position the cloth vehicle of the dyeing plant, so that the positioning precision of the cloth vehicle of the dyeing plant is improved, and the positioning cost can be reduced.

Description

Technical Field

[0001] This application relates to the field of textile technology, specifically to a Zigbee-based dyeing plant fabric cart positioning system and method. Background Technology

[0002] In textile printing and dyeing factories, fabric carts (or pushcarts) are commonly used for storing and transporting fabrics. A dyeing and finishing workshop typically has hundreds to thousands of fabric carts. Due to the lack of a digital and traceable management system, dyeing factory employees often cannot find the fabric cart corresponding to their fabric, wasting a lot of time on the "finding fabric" process. Sometimes, to save time, they even reproduce the fabric, resulting in significant waste. Currently, fabric cart positioning is achieved through steps such as "workshop marking," "manually recording the fabric cart position," and "manually binding the fabric to the cart." However, with the development of flexible and customized demands in recent years, "small batches and multiple varieties" have become the trend in the textile industry, resulting in the phenomenon of "one cart with multiple fabrics" and "one fabric with multiple carts." Fabric positioning is even more difficult to manage, and relying solely on manual recording of fabric cart positions can no longer meet the needs. There is an urgent need for a high-precision, low-cost, and low-power positioning method.

[0003] Currently, the most accurate positioning method on the market is UWB, with an accuracy of 0.1 meters. However, it is extremely expensive, costing hundreds of thousands of yuan for a positioning system in a medium-sized dyeing factory, and it also has high power consumption. Next is Bluetooth AOA technology, which can achieve high-precision positioning (1.5-3 meters), with low power consumption and long battery life. However, its disadvantage is short transmission distance, requiring a large number of base stations, making its overall cost not much cheaper than UWB. The lowest accuracy is achieved with Zigbee technology, which has the lowest cost but also the lowest positioning accuracy (3-10 meters).

[0004] Currently, all solutions rely on the positioning tags continuously sending coordinate data to the base station. If the deployment vehicle remains stationary in one location for an extended period, this method results in significant energy waste and shortens battery replacement time. Replacing the battery requires removing the tag, increasing the probability of human error. However, since ordinary positioning tags only contain a communication module and lack a motion status detection unit, power consumption remains uncontrolled.

[0005] In conclusion, no positioning solution currently meets the requirements of high accuracy, low power consumption, and low cost simultaneously. Summary of the Invention

[0006] In view of the above problems, this application provides a Zigbee-based positioning system and method for textile dyeing and printing factories, which solves the problem of lack of high-precision and low-cost positioning methods for textile dyeing and printing factories.

[0007] To achieve the above objectives, the inventors provide a Zigbee-based dyeing plant fabric cart positioning system, comprising:

[0008] The perception layer includes multiple positioning tags, which are installed on the dyeing plant's fabric cart. Each positioning tag includes an IMU sensor module, a Zigbee communication module, and a battery system. The IMU sensor module is used to acquire the pose data of the dyeing plant's fabric cart, the Zigbee communication module is used to acquire the Zigbee positioning signal and wireless communication of the dyeing plant's fabric cart, and the battery system is used to power the sensor module and the Zigbee communication module.

[0009] The network layer includes Zigbee base stations and factory local area networks, and is used for data transmission between the perception layer and the platform layer.

[0010] The platform layer is used to obtain the relative displacement and heading angle of the dyeing plant fabric cart based on the pose data of the dyeing plant fabric cart when the position of the dyeing plant fabric cart changes, and to obtain the absolute position of the dyeing plant fabric cart based on the Zigbee positioning signal of the dyeing plant fabric cart. The calculated relative displacement and absolute position are fused to obtain the positioning result of the dyeing plant fabric cart, and the positioning result of the dyeing plant fabric cart is sent to the application layer.

[0011] The application layer is used to visualize the positioning results of the dyeing plant fabric cart sent by the platform layer.

[0012] In some embodiments, the IMU sensor module includes an accelerometer and a gyroscope. Specifically, the platform layer is used to collect the mixed acceleration of the dyeing plant fabric cart through the accelerometer and the angular velocity of the dyeing plant fabric cart through the gyroscope when the dyeing plant fabric cart is moving; subtract the gravitational acceleration vector from the collected mixed acceleration to obtain the motion acceleration; integrate the motion acceleration once to obtain the velocity; determine whether the dyeing plant fabric cart is stationary; if it is stationary, integrate the velocity once to obtain the relative displacement of the dyeing plant fabric cart; and integrate the angular velocity to obtain the heading angle of the dyeing plant fabric cart.

[0013] In some embodiments, the platform layer is further used to calculate the current acceleration variance and angular velocity variance of the dyeing plant fabric cart. When the acceleration variance is less than the acceleration variance threshold and the angular velocity variance is less than the angular velocity variance threshold, it is determined that the dyeing plant fabric cart is currently stationary.

[0014] In some embodiments, the platform layer is specifically used to calculate the relative displacement of the dyeing plant fabric cart based on the pose data collected by the IMU sensor module, then to obtain the filtered relative displacement by high-frequency filtering of the calculated relative displacement, and to obtain the filtered absolute position by low-pass filtering of the absolute position of the dyeing plant fabric cart calculated based on the Zigbee signal according to the memory coefficient, and to obtain the filtered absolute position by fusing the filtered relative displacement and the filtered absolute position to obtain the positioning result of the dyeing plant fabric cart.

[0015] In some embodiments, the positioning tag is also used to enter a deep sleep mode when the dyeing plant's fabric cart remains stationary for more than a preset time, thereby shutting down the Zigbee communication module and controlling the IMU sensor module to operate at a preset power consumption. When the IMU sensor detects that the acceleration exceeds a preset threshold, the Zigbee communication module is woken up and the IMU sensor module is controlled to operate at normal power.

[0016] In some embodiments, the location tag is also used to periodically wake up the Zigbee communication module to send a heartbeat packet to the platform layer when in deep sleep mode.

[0017] In some embodiments, the platform layer is further used to divide the high-precision digital map of the dyeing factory area into several grids, obtain the marker of each grid, the marker including walkable or non-walkable, perform pixel dilation on the grid area marked as non-walkable, fuse the calculated relative displacement and absolute position to obtain the position coordinates of the dyeing factory fabric cart and place them on the map. If the position coordinates are in the walkable area, the position coordinates are taken as the final positioning result. If the position coordinates are in the non-walkable area, the search radius is expanded with the position coordinates as the center until a grid marked as walkable is found, and the center position of the grid is taken as the positioning result for this time.

[0018] Another technical solution is also provided: a Zigbee-based method for locating fabric carts in dyeing plants. This method is applied to the aforementioned Zigbee-based positioning system for fabric carts in dyeing plants, and includes the following steps:

[0019] When the positioning tag on the dyeing plant fabric cart detects that the dyeing plant fabric cart has entered the running state, it collects the pose data of the dyeing plant fabric cart through the IMU sensor module and obtains the Zigbee positioning signal of the dyeing plant fabric cart through the Zigbee communication module.

[0020] The collected pose data and Zigbee positioning signals of the dyeing factory's fabric carts are sent to the platform layer;

[0021] The platform layer obtains the relative displacement and heading angle of the dyeing plant fabric cart based on its pose data, and obtains the absolute position of the dyeing plant fabric cart based on its Zigbee positioning signal. The calculated relative displacement and absolute position are then fused to obtain the positioning result of the dyeing plant fabric cart.

[0022] The location results of the dyeing plant's fabric carts are sent to the application layer for visualization.

[0023] In some embodiments, the IMU sensor module includes an accelerometer and a gyroscope;

[0024] The platform layer obtains the relative displacement and heading angle of the dyeing plant fabric cart based on its pose data, specifically including the following steps:

[0025] The acceleration sensor collects the mixed acceleration of the dyeing factory's fabric cart, and subtracts the gravitational acceleration vector to obtain the motion acceleration;

[0026] The velocity is obtained by integrating the acceleration.

[0027] Determine whether the dyeing plant fabric cart is stationary. If it is stationary, integrate the velocity to obtain the relative displacement of the dyeing plant fabric cart, and integrate the angular velocity to obtain the heading angle of the dyeing plant fabric cart.

[0028] In some embodiments, fusing the calculated relative displacement and absolute position to obtain the positioning result of the dyeing plant fabric cart specifically includes the following steps:

[0029] The platform layer divides the high-precision digital map of the dyeing plant area into several grids and obtains the markers for each grid, including whether it is walkable or not walkable.

[0030] Perform pixel dilation on grid regions marked as unwalkable;

[0031] The calculated relative displacement and absolute position are fused together to obtain the position coordinates of the dyeing factory's fabric cart, which are then placed on the map.

[0032] If the location coordinates are within the walkable area, then the location coordinates are taken as the final location result;

[0033] If the location coordinates are in an unwalkable area, expand the search radius using the location coordinates as the center until a walkable grid is found, and use the center of that grid as the location result for this operation.

[0034] Unlike existing technologies, the above technical solution involves setting positioning tags on the dyeing plant's fabric carts. The positioning tag integrates an IMU sensor module, a Zigbee communication module, and a battery module. The battery module powers the IMU sensor module, Zigbee communication module, and other components within the tag. When the dyeing plant fabric cart is in motion, the IMU sensor module acquires the cart's pose data, and the Zigbee communication module acquires the Zigbee positioning signal. The pose data and Zigbee positioning signal are then transmitted to the platform layer via a network layer composed of a Zigbee base station and the plant's local area network. The platform layer determines the cart's relative displacement and heading based on the pose data and calculates its absolute position based on the Zigbee positioning signal. By fusing the relative displacement and absolute position, the positioning result is obtained and visualized at the application layer. This combination of the IMU sensor module and Zigbee communication module for positioning the dyeing plant fabric cart not only improves positioning accuracy but also reduces positioning costs.

[0035] The above description of the invention is merely an overview of the technical solution of this application. In order to enable those skilled in the art to better understand the technical solution of this application and to implement it based on the description and drawings, and to make the above-mentioned objectives and other objectives, features and advantages of this application easier to understand, the following description is provided in conjunction with the specific embodiments and drawings of this application. Attached Figure Description

[0036] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, features, and effects of specific embodiments of this application and other related content, and should not be considered as limitations on this application.

[0037] In the accompanying drawings of the instruction manual:

[0038] Figure 1 A schematic diagram of a Zigbee-based dyeing plant fabric cart positioning system as described in a specific implementation;

[0039] Figure 2 A schematic diagram of the structure of the positioning tag described in a specific implementation;

[0040] Figure 3 This is a schematic diagram of one possible structure of the IMU sensor module described in a specific implementation.

[0041] Figure 4 A flowchart illustrating a Zigbee-based dyeing plant fabric cart positioning method as described in a specific implementation;

[0042] Figure 5This is a schematic diagram illustrating a process for the platform layer to obtain the relative displacement and heading angle of the dyeing plant fabric cart based on the pose data of the dyeing plant fabric cart in a specific implementation method.

[0043] The reference numerals used in the above figures are explained as follows:

[0044] 110. Perception layer

[0045] 111. Location tag,

[0046] 120. Network layer

[0047] 121. Zigbee base station

[0048] 122. Factory local area network,

[0049] 130. Platform layer

[0050] 140. Application Layer

[0051] 210. IMU sensor module

[0052] 211. Accelerometer sensor

[0053] 212. Gyroscope

[0054] 220. Zigbee communication module.

[0055] 230. Battery system. Detailed Implementation

[0056] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.

[0057] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.

[0058] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.

[0059] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.

[0060] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order between these entities or operations.

[0061] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.

[0062] As understood in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.

[0063] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0064] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0065] Please see Figure 1-2 This embodiment describes a Zigbee-based dyeing plant fabric cart positioning system, comprising:

[0066] The sensing layer 110 includes multiple positioning tags 111, which are installed on the dyeing plant fabric cart. Each positioning tag 111 includes an IMU sensor module 210, a Zigbee communication module 220, and a battery system 230. The IMU sensor module 210 is used to acquire the pose data of the dyeing plant fabric cart, the Zigbee communication module 220 is used to acquire the Zigbee positioning signal and wireless communication of the dyeing plant fabric cart, and the battery system 230 is used to power the sensor module and the Zigbee communication module 220.

[0067] Network layer 120, which includes Zigbee base station 121 and factory local area network 122, is used for data transmission between perception layer 110 and platform layer 130.

[0068] Platform layer 130 is used to obtain the relative displacement and heading angle of the dyeing plant fabric cart based on the pose data of the dyeing plant fabric cart when the position of the dyeing plant fabric cart changes, and to obtain the absolute position of the dyeing plant fabric cart based on the Zigbee positioning signal of the dyeing plant fabric cart. The calculated relative displacement and absolute position are fused to obtain the positioning result of the dyeing plant fabric cart, and the positioning result of the dyeing plant fabric cart is sent to the application layer 140.

[0069] Application layer 140 is used to visualize the positioning results of the dyeing plant fabric cart sent by platform layer 130.

[0070] A positioning tag 111 is installed on the dyeing plant's fabric cart. The positioning tag 111 has a built-in IMU sensor module 210, a Zigbee communication module 220, and a battery module. The battery module powers the IMU sensor module 210, Zigbee communication module 220, and other components within the positioning tag 111. When the dyeing plant's fabric cart is in motion, the IMU sensor module 210 acquires the cart's pose data, and the Zigbee communication module 220 acquires the cart's Zigbee positioning signal. The pose data and Zigbee positioning signal are then transmitted via a Zigbee base station 121 and the plant's local area network 1. The network layer 120, composed of 22 components, sends data to the platform layer 130. The platform layer 130 obtains the relative displacement and heading of the dyeing plant fabric cart based on its pose data, and calculates the absolute position of the dyeing plant fabric cart based on its Zigbee positioning signal. By fusing the relative displacement and absolute position of the dyeing plant fabric cart, the positioning result of the dyeing plant fabric cart is obtained. The positioning result is then visualized in the application layer 140. The positioning of the dyeing plant fabric cart is achieved through the IMU sensor module 210 combined with the Zigbee communication module 220, which not only improves the positioning accuracy of the dyeing plant fabric cart but also reduces positioning costs.

[0071] Please see Figure 3 In some embodiments, the IMU sensor module 210 includes an accelerometer 211 and a gyroscope 212. The platform layer 130 is specifically used to collect the mixed acceleration of the dyeing factory fabric cart through the accelerometer 211 and the angular velocity of the dyeing factory fabric cart through the gyroscope 212 when the dyeing factory fabric cart is moving; subtract the gravitational acceleration vector from the collected mixed acceleration to obtain the motion acceleration; integrate the motion acceleration once to obtain the velocity; determine whether the dyeing factory fabric cart is in a stationary state; if it is in a stationary state, integrate the velocity once to obtain the relative displacement of the dyeing factory fabric cart; and integrate the angular velocity to obtain the heading angle of the dyeing factory fabric cart.

[0072] IMU trajectory compensation:

[0073] IMU is an abbreviation for Inertial Measurement Unit. It obtains the motion trajectory based on the accelerometer records, and then calculates the relative displacement and heading change of the vehicle relative to the previous known point, thereby improving positioning accuracy and realizing continuous tracking.

[0074] Measurement data acquisition

[0075] Acceleration and angular velocity are measurement data that the accelerometer and gyroscope 212 in the IMU module can acquire. The starting point of the vehicle has an initial coordinate system [x0, y0, z0] and an initial heading angle ψ0. When the vehicle moves, the vector measured by the accelerometer is the vector sum of the motion vector and the gravity vector. The projection of this vector in the vehicle coordinate system is aa = [aa...].x ,aa y ,aa z The gyroscope 212 is responsible for sensing the direction of motion, and the angular velocity it provides is g = [g...]. x ,g y ,g z ].

[0076] Accelerometer processing and integration

[0077] Because the acceleration in the IMU module is a mixture of gravitational acceleration, it is necessary to separate the acceleration caused by vehicle motion from the IMU's acceleration data. In the navigation coordinate system, acceleration aa = [aa...] x ,aa y ,aa z Subtracting the gravitational acceleration vector [0, 0, 9.8] m / s², we obtain the pure vehicle acceleration a = [a x ,a y ,a z ].

[0078] Then, the velocity is obtained through a single integration:

[0079] ;

[0080] To determine if the dyeing factory's fabric cart is stationary, if it is determined to be moving, the acceleration is integrated normally. If the cart is determined to be stationary, the current velocity vector is set to zero; then, the velocity is integrated again to obtain the cart's displacement Δs.

[0081] .

[0082] Dead reckoning:

[0083] Calculate the new absolute coordinates based on the relative displacement and heading:

[0084] ;

[0085] in, These are the previously known absolute coordinates.

[0086] The current heading angle ψ is obtained by the following formula:

[0087] ;

[0088] Where gz represents the z component of the angular velocity g=[gx,gy,gz] collected by gyroscope 212.

[0089] In some embodiments, the platform layer 130 is further specifically configured to calculate the current acceleration variance and angular velocity variance of the dyeing factory cloth vehicle. When the acceleration variance is less than the acceleration variance threshold and the angular velocity variance is less than the angular velocity variance threshold, it is determined that the current dyeing factory cloth vehicle is in a stationary state.

[0090] Perform speed zeroing correction. This is because when the system detects that the cloth vehicle is in a stationary state, forcibly setting the current speed v to zero can effectively offset the speed drift caused by the accelerometer zero bias. The specific implementation method is as follows: First, set the acceleration variance threshold THa and the angular velocity variance threshold THg, and then calculate the current acceleration variance Vara and the angular velocity variance Varg. If both Vara < THa and Varg < THg are satisfied simultaneously. The specific calculation methods of the acceleration variance Vara and the angular velocity variance Varg are as follows:

[0091] Continuously monitor the data collected by the IMU sensor module 210 and perform variance calculations in real time, including acceleration variance and angular velocity variance. To prevent data jumps, a sliding data window needs to be set to store the data of the most recent N sampling periods, take the average value of these data within the window, and then calculate the variance. The specific operations are as follows:

[0092] The average value within the window of the accelerometer is:

[0093] ;

[0094] The acceleration variance is:

[0095] ;

[0096] The average value within the window of the angular velocity is:

[0097] ;

[0098] The angular velocity variance is:

[0099] .

[0100] In some embodiments, the platform layer 130 is specifically configured to calculate the relative displacement of the dyeing factory cloth vehicle based on the pose data collected by the IMU sensor module 210, obtain the filtered relative displacement by high-frequency filtering the calculated relative displacement, perform low-pass filtering on the absolute position of the dyeing factory cloth vehicle calculated according to the zigbee signal according to the memory coefficient to obtain the filtered absolute position, and fuse the filtered relative displacement and the filtered absolute position to obtain the positioning result of the dyeing factory cloth vehicle.

[0101] Complementary filter fusion correction:

[0102] Zigbee positioning signals are low-frequency signals, updating slowly and providing absolute position with a delay. In contrast, the IMU sensor module 210 updates in real time using relative displacement calculated through integration, a high-frequency signal capable of capturing instantaneous motion. Combining the two enables high-precision real-time positioning. The strengths of each can be leveraged to compensate for their weaknesses, based on the characteristics of their signals in different frequency bands.

[0103] The basic idea of ​​the fusion is as follows: The relative displacement calculated by the IMU sensor module 210 through integration (i.e., the result of the previous step) is passed through a high-pass filter to filter out its low-frequency drift components, retaining only its high-frequency dynamic response; the absolute position provided by the ZigBee is passed through a low-pass filter. This filters out its high-frequency noise and jumps, retaining only its low-frequency stable reference; the high-pass filtered IMU displacement is added to the low-pass filtered ZigBee position to obtain the final fused position.

[0104] Define the current location coordinates of Zigbee as [x zigbee , y zigbee The relative displacement calculated by the IMU module is [Δx]. imu , Δy imu The current coordinates calculated by the IMU are: The coordinates after merging the two are [x fused ,y fused To distinguish between the previous step and this step, and to maintain consistency with the quantities appearing in previous formulas, the fused coordinates of the previous step are defined as follows: The following are the specific implementation steps:

[0105] High-pass filtering removes low-frequency signals:

[0106] The high-pass filter uses a differential form. The low-frequency signal is the Zigbee coordinate data. After filtering it out, the remaining high-frequency component is the displacement value [Δximu, Δyimu] calculated by the IMU module. Therefore, the high-pass filter branch is obtained:

[0107] ;

[0108] Calculation of the low-pass filter branch:

[0109] A standard first-order infinite impulse response (IIR) low-pass filter is used, with a defined filter memory coefficient α, where 0 < α < 1. When α is close to 1, the system has "long memory," historical data has a high weight, and it is not sensitive to new changes; in this case, Zigbee coordinate data plays a dominant role. When α is close to 0, the system has "short memory," current input has a high weight, and it can quickly track changes; in this case, real-time coordinate data calculated by the IMU plays a dominant role. The specific value is determined based on actual experimental data. The specific form of the low-pass filter is as follows:

[0110] ;

[0111] Fusion Positioning:

[0112] The high-frequency dynamic components of the IMU are added to the low-frequency reference components of the ZigBee to obtain the final optimal estimated position:

[0113] ;

[0114] [x] fused , y fused This is the final merged position output at this moment.

[0115] Update status and prepare for the next cycle.

[0116] The location of this round of fusion is saved as the "fusion result of the previous moment" for the next round:

[0117] ;

[0118] Thus, through complementary filtering correction, a final position that is both stable and sensitive is obtained.

[0119] In some embodiments, the platform layer 130 is further configured to divide the high-precision digital map of the dyeing factory area into several grids, obtain the markers of each grid, the markers including walkable or non-walkable, perform pixel dilation on the grid areas marked as non-walkable, fuse the calculated relative displacement and absolute position to obtain the position coordinates of the dyeing factory fabric carts and place them on the map. If the position coordinates are in the walkable area, the position coordinates are used as the final positioning result. If the position coordinates are in the non-walkable area, the search radius is expanded with the position coordinates as the center until a grid marked as walkable is found, and the center position of the grid is used as the positioning result for this time.

[0120] Digital map constraint correction

[0121] Because Zigbee positioning inherently has significant positioning errors, and the position calculation of an IMU operating alone can diverge infinitely over time, even due to factors such as the metal surfaces of equipment causing signal blind spots, vehicle positioning may become distorted and enter inaccessible areas such as inside walls or equipment. Therefore, it is necessary to constrain the digital map and introduce prior geographical knowledge to correct the physical inconsistencies of pure signal positioning. This patent proposes to use a "projection correction method" for this purpose, with the specific steps as follows:

[0122] Map modeling:

[0123] The high-precision digital map of the factory area is divided into a fine grid, with each grid marked as "walkable" or "non-walkable". Then, all "non-walkable" areas are expanded by a certain number of pixels to ensure that the physical dimensions of the vehicle do not intersect with obstacles.

[0124] Walkability assessment:

[0125] The position coordinates [x] obtained in the previous step of "complementary filter fusion correction" are used to... fused , y fused Place it on the map and compare it with the map to determine whether it is in the "walkable" area.

[0126] Projection correction:

[0127] If [x] fused , y fused If the location is within the "walkable" area, then that point will be accepted as the location result for this time.

[0128] If [x] fused , y fused If the point is located within an "unwalkable" area, the search radius is gradually expanded using that point as the center until a "walkable" grid is found. The point is then corrected to the center of that grid, thus projecting it onto the boundary of the nearest "walkable" area. The corrected coordinates are then output as the localization result.

[0129] By using digital map constraint correction, the positioning trajectory of the vehicle is always constrained within a reasonable physical space, eliminating unreasonable positioning phenomena such as "passing through walls" caused by signal drift and jumps, and significantly improving the reliability and accuracy of the system.

[0130] In some embodiments, the positioning tag 111 is also used to enter a deep sleep mode when the dyeing plant fabric cart is stationary for more than a preset time, turn off the Zigbee communication module 220, and control the IMU sensor module 210 to work at a preset power consumption. When the IMU sensor detects that the acceleration exceeds a preset threshold, the Zigbee communication module 220 is woken up and the IMU sensor module 210 is controlled to work at normal power.

[0131] The positioning system achieves ultra-low power consumption through an intelligent sleep and wake-up mechanism. Since repeated positioning is unnecessary when the vehicle is parked for extended periods, the Zigbee communication module 220 can be disabled, leaving only the IMU sensor module 210 operational. The Zigbee communication module 220 is then woken up when the vehicle is moved and the IMU sensor module 210 receives a clear reading. Thus, by incorporating an IMU module into the positioning tag 111, both high accuracy and low power consumption are achieved.

[0132] The specific implementation steps of the intelligent sleep and wake-up mechanism are as follows:

[0133] Set vibration threshold:

[0134] Configure the motion detection interrupt for the IMU accelerometer. Set a suitable vibration threshold. When the Zigbee communication module 220 is in deep sleep, the IMU sensor module 210 continuously monitors acceleration at extremely low power (a few μA). This threshold needs to be carefully calibrated to ignore environmental vibrations such as people walking, doors closing, and forklifts moving, while reliably responding to the action of a cart being pushed away.

[0135] Trigger wake-up:

[0136] Once the acceleration exceeds the threshold, the IMU sensor module 210 immediately wakes up the Zigbee communication module 220, which is in deep sleep, through a hardware interrupt. The tag's Zigbee communication module 220 and IMU sensor module 210 then run at full speed to collect and report positioning data at a normal frequency.

[0137] In some embodiments, the location tag 111 is also used to periodically wake up the Zigbee communication module 220 to send a heartbeat packet to the platform layer 130 when in deep sleep mode.

[0138] To prevent the system from "freezing," a timer interrupt needs to be set in deep sleep mode to wake up the system periodically and send a heartbeat packet to the backend server to indicate that the server is "fault-free."

[0139] In some embodiments, the Zigbee-based dyeing plant fabric cart positioning system is divided into four levels:

[0140] Perception Layer: The perception layer consists of multiple positioning tags, which are divided into three main parts: a communication module, a sensor system, and a battery system. The sensor system includes a MEMS inertial measurement unit (IMU), an accelerometer, and a gyroscope. Since these three components can be integrated into a single IMU, the sensor system will be referred to as the "IMU sensor module" below.

[0141] Network layer: mainly used for data transmission, including base stations and local area networks in factories.

[0142] Platform layer: mainly used for data processing, including modules such as IMU trajectory compensation, fusion positioning algorithm, map matching, and low-power algorithm.

[0143] Application layer: Ultimately, it enables business visualization, links with ERP and MES systems, and allows real-time viewing of the location of fabrics.

[0144] Please see Figure 4In another embodiment, a Zigbee-based method for locating fabric carts in a dyeing plant, the method being applied to the aforementioned Zigbee-based dyeing plant fabric cart positioning system, includes the following steps:

[0145] Step S410: When the positioning tag on the dyeing plant fabric cart detects that the dyeing plant fabric cart has entered the running state, the IMU sensor module collects the pose data of the dyeing plant fabric cart and the Zigbee positioning signal of the dyeing plant fabric cart is obtained through the Zigbee communication module.

[0146] Step S420: Send the collected pose data and Zigbee positioning signal of the dyeing plant fabric cart to the platform layer;

[0147] Step S430: The platform layer obtains the relative displacement and heading angle of the dyeing plant fabric cart based on the pose data of the dyeing plant fabric cart, and obtains the absolute position of the dyeing plant fabric cart based on the Zigbee positioning signal of the dyeing plant fabric cart. The calculated relative displacement and absolute position are fused to obtain the positioning result of the dyeing plant fabric cart.

[0148] Step S440: Send the positioning results of the dyeing plant's fabric cart to the application layer for visualization.

[0149] By setting positioning tags on the fabric carts in the dyeing factory. The positioning tag integrates an IMU sensor module, a Zigbee communication module, and a battery module. The battery module powers the IMU sensor module, Zigbee communication module, and other components within the tag. When the dyeing plant fabric cart is in motion, the IMU sensor module acquires the cart's pose data, and the Zigbee communication module acquires the Zigbee positioning signal. The pose data and Zigbee positioning signal are then transmitted to the platform layer via a network layer composed of a Zigbee base station and the plant's local area network. The platform layer determines the cart's relative displacement and heading based on the pose data and calculates its absolute position based on the Zigbee positioning signal. By fusing the relative displacement and absolute position, the positioning result is obtained and visualized at the application layer. This combination of the IMU sensor module and Zigbee communication module for positioning the dyeing plant fabric cart not only improves positioning accuracy but also reduces positioning costs.

[0150] In some embodiments, the IMU sensor module includes an accelerometer and a gyroscope;

[0151] Please see Figure 5 The platform layer obtains the relative displacement and heading angle of the dyeing plant fabric cart based on its pose data, specifically including the following steps:

[0152] Step S510: The acceleration sensor collects the mixed acceleration of the dyeing factory's fabric cart and subtracts the gravitational acceleration vector to obtain the motion acceleration;

[0153] Step S520: Integrate the acceleration once to obtain the velocity;

[0154] Step S530: Determine whether the dyeing plant's fabric cart is stationary;

[0155] If the vehicle is stationary, proceed to step S540: Integrate the velocity once to obtain the relative displacement of the dyeing plant fabric cart, and integrate the angular velocity to obtain the heading angle of the dyeing plant fabric cart.

[0156] IMU trajectory compensation:

[0157] IMU is an abbreviation for Inertial Measurement Unit. It obtains the motion trajectory based on the accelerometer records, and then calculates the relative displacement and heading change of the vehicle relative to the previous known point, thereby improving positioning accuracy and realizing continuous tracking.

[0158] Measurement data acquisition

[0159] Acceleration and angular velocity are measurement data acquired by the accelerometer and gyroscope in the IMU module. The starting point of the vehicle has an initial coordinate system [x0, y0, z0] and an initial heading angle ψ0. When the vehicle moves, the vector measured by the accelerometer is the vector sum of the motion vector and the gravity vector. The projection of this vector onto the vehicle's coordinate system is aa = [aa...]. x ,aa y ,aa z The gyroscope is responsible for sensing the direction of motion, and the angular velocity it provides is g = [g...]. x ,g y ,g z ].

[0160] Accelerometer processing and integration

[0161] Because the acceleration in the IMU module is a mixture of gravitational acceleration, it is necessary to separate the acceleration caused by vehicle motion from the IMU's acceleration data. In the navigation coordinate system, acceleration aa = [aa...] x ,aa y ,aa z Subtracting the gravitational acceleration vector [0, 0, 9.8] m / s², we obtain the pure vehicle acceleration a = [a x ,a y ,a z ].

[0162] Then, the velocity is obtained through a single integration:

[0163] ;

[0164] Determine whether the fabric cart in the dyeing factory is in a stationary state. If it is determined to be in a moving state, integrate the acceleration normally. If it is determined that the fabric cart in the dyeing factory is in a stationary state, set the velocity vector at the current moment to zero; then integrate the velocity once again to obtain the displacement Δs of the fabric cart:

[0165] .

[0166] Dead reckoning:

[0167] Calculate the new absolute coordinates based on the relative displacement and heading:

[0168] ;

[0169] where, is the previous known absolute coordinate.

[0170] And the current dead reckoning angle ψ is obtained by the following formula:

[0171] ;

[0172] where, gz represents the z - component of the angular velocity g = [gx, gy, gz] collected by the gyroscope.

[0173] In some embodiments, determining whether the fabric cart in the dyeing factory is in a stationary state specifically includes the following steps:

[0174] Calculate the current acceleration variance and angular velocity variance of the fabric cart in the dyeing factory. When the acceleration variance is less than the acceleration variance threshold and the angular velocity variance is less than the angular velocity variance threshold, it is determined that the current fabric cart in the dyeing factory is in a stationary state.

[0175] Perform velocity zeroing correction. This is because when the system detects that the fabric cart is in a stationary state, forcing the current velocity v to be set to zero can effectively cancel out the velocity drift caused by the accelerometer zero - bias. The specific implementation method is: first set the acceleration variance threshold THa and the angular velocity variance threshold THg, then calculate the current acceleration variance Vara and the angular velocity variance Varg. If both Vara < THa and Varg < THg are satisfied simultaneously. The specific calculation methods of the acceleration variance Vara and the angular velocity variance Varg are as follows:

[0176] Continuously monitor the data collected by the IMU sensor module and calculate the variance in real - time, including the acceleration variance and the angular velocity variance. To prevent data jumps, a sliding data window needs to be set to store the data of the last N sampling periods, take the average value of these data within the window, and then calculate the variance. The specific operations are as follows:

[0177] The average value within the window of the accelerometer is:

[0178] ;

[0179] The variance of acceleration is:

[0180] ;

[0181] The average value within the angular velocity window is:

[0182] ;

[0183] The variance of angular velocity is:

[0184] .

[0185] In some embodiments, fusing the calculated relative displacement and absolute position to obtain the positioning result of the dyeing plant fabric cart specifically includes the following steps:

[0186] After calculating the relative displacement of the dyeing plant fabric cart based on the pose data collected by the IMU sensor module, the calculated relative displacement is filtered by high-frequency filtering. The absolute position of the dyeing plant fabric cart calculated from the Zigbee signal is then filtered by low-pass filtering based on the memory coefficient to obtain the filtered absolute position. The filtered relative displacement and the filtered absolute position are then fused to obtain the positioning result of the dyeing plant fabric cart.

[0187] Complementary filter fusion correction:

[0188] Zigbee positioning signals are low-frequency signals, updating slowly and providing absolute position with a delay. In contrast, IMU sensor modules update in real-time by calculating relative displacement through integration, using high-frequency signals to capture instantaneous motion. Combining the two enables high-precision real-time positioning. The strengths of each can be leveraged to compensate for their weaknesses based on the characteristics of their signals in different frequency bands.

[0189] The basic idea of ​​the fusion is as follows: The relative displacement calculated by the IMU sensor module through integration (i.e., the result of the previous step) is passed through a high-pass filter to remove its low-frequency drift components, retaining only its high-frequency dynamic response; the absolute position provided by the ZigBee is passed through a low-pass filter. This removes its high-frequency noise and jumps, retaining only its low-frequency stable reference; the high-pass filtered IMU displacement is added to the low-pass filtered ZigBee position to obtain the final fused position.

[0190] Define the current location coordinates of Zigbee as [x zigbee , y zigbee The relative displacement calculated by the IMU module is [Δx]. imu , Δy imu The current coordinates calculated by the IMU are: The coordinates after merging the two are [x fused ,y fused To distinguish between the previous step and this step, and to maintain consistency with the quantities appearing in previous formulas, the fused coordinates of the previous step are defined as follows: The following are the specific implementation steps:

[0191] High-pass filtering removes low-frequency signals:

[0192] The high-pass filter uses a differential form. The low-frequency signal is the Zigbee coordinate data. After filtering it out, the remaining high-frequency component is the displacement value [Δximu, Δyimu] calculated by the IMU module. Therefore, the high-pass filter branch is obtained:

[0193] ;

[0194] Calculation of the low-pass filter branch:

[0195] A standard first-order infinite impulse response (IIR) low-pass filter is used, with a defined filter memory coefficient α, where 0 < α < 1. When α is close to 1, the system has "long memory," historical data has a high weight, and it is not sensitive to new changes; in this case, Zigbee coordinate data plays a dominant role. When α is close to 0, the system has "short memory," current input has a high weight, and it can quickly track changes; in this case, real-time coordinate data calculated by the IMU plays a dominant role. The specific value is determined based on actual experimental data. The specific form of the low-pass filter is as follows:

[0196] ;

[0197] Fusion Positioning:

[0198] The high-frequency dynamic components of the IMU are added to the low-frequency reference components of the ZigBee to obtain the final optimal estimated position:

[0199] ;

[0200] [x] fused , y fused This is the final merged position output at this moment.

[0201] Update status and prepare for the next cycle.

[0202] The location of this round of fusion is saved as the "fusion result of the previous moment" for the next round:

[0203] ;

[0204] Thus, through complementary filtering correction, a final position that is both stable and sensitive is obtained.

[0205] In some embodiments, fusing the calculated relative displacement and absolute position to obtain the positioning result of the dyeing plant fabric cart specifically includes the following steps:

[0206] The platform layer divides the high-precision digital map of the dyeing plant area into several grids and obtains the markers for each grid, including whether it is walkable or not walkable.

[0207] Perform pixel dilation on grid regions marked as unwalkable;

[0208] The calculated relative displacement and absolute position are fused together to obtain the position coordinates of the dyeing factory's fabric cart, which are then placed on the map.

[0209] If the location coordinates are within the walkable area, then the location coordinates are taken as the final location result;

[0210] If the location coordinates are in an unwalkable area, expand the search radius using the location coordinates as the center until a walkable grid is found, and use the center of that grid as the location result for this operation.

[0211] Digital map constraint correction

[0212] Because Zigbee positioning inherently has significant positioning errors, and the position calculation of an IMU operating alone can diverge infinitely over time, even due to factors such as the metal surfaces of equipment causing signal blind spots, vehicle positioning may become distorted and enter inaccessible areas such as inside walls or equipment. Therefore, it is necessary to constrain the digital map and introduce prior geographical knowledge to correct the physical inconsistencies of pure signal positioning. This patent proposes to use a "projection correction method" for this purpose, with the specific steps as follows:

[0213] Map modeling:

[0214] The high-precision digital map of the factory area is divided into a fine grid, with each grid marked as "walkable" or "non-walkable". Then, all "non-walkable" areas are expanded by a certain number of pixels to ensure that the physical dimensions of the vehicle do not intersect with obstacles.

[0215] Walkability assessment:

[0216] The position coordinates [x] obtained in the previous step of "complementary filter fusion correction" are used to... fused , y fused Place it on the map and compare it with the map to determine whether it is in the "walkable" area.

[0217] Projection correction:

[0218] If [x] fused , y fusedIf the location is within the "walkable" area, then that point will be accepted as the location result for this time.

[0219] If [x] fused , y fused If the point is located within an "unwalkable" area, the search radius is gradually expanded using that point as the center until a "walkable" grid is found. The point is then corrected to the center of that grid, thus projecting it onto the boundary of the nearest "walkable" area. The corrected coordinates are then output as the localization result.

[0220] By using digital map constraint correction, the positioning trajectory of the vehicle is always constrained within a reasonable physical space, eliminating unreasonable positioning phenomena such as "passing through walls" caused by signal drift and jumps, and significantly improving the reliability and accuracy of the system.

[0221] In some embodiments, the following steps are also included:

[0222] When the dyeing plant's fabric cart remains stationary for more than a preset time, the positioning tag enters a deep sleep mode, shuts down the Zigbee communication module, and controls the IMU sensor module to operate at a preset power consumption.

[0223] When the IMU sensor detects that the acceleration exceeds the preset threshold, the Zigbee communication module is woken up and the IMU sensor module is controlled to operate at normal power.

[0224] The positioning system achieves ultra-low power consumption through an intelligent sleep and wake-up mechanism. Since repeated positioning is unnecessary when the vehicle is parked for extended periods, the Zigbee communication module can be disabled, leaving only the IMU sensor module operational. The Zigbee communication module is then woken up when the vehicle is moved and the IMU sensor module has a clear reading. In this way, by incorporating an IMU module into the positioning tag, both high accuracy and low power consumption are achieved.

[0225] The specific implementation steps of the intelligent sleep and wake-up mechanism are as follows:

[0226] Set vibration threshold:

[0227] Configure the motion detection interrupt for the IMU accelerometer. Set a suitable vibration threshold. When the Zigbee communication module is in deep sleep, the IMU sensor module continuously monitors acceleration at extremely low power (a few μA). This threshold needs to be carefully calibrated to ignore environmental vibrations such as people walking, doors closing, and forklifts moving, while reliably responding to the action of a cart being pushed away.

[0228] Trigger wake-up:

[0229] Once the acceleration exceeds the threshold, the IMU sensor module immediately wakes up the Zigbee communication module, which is in deep sleep, through a hardware interrupt. The tag's ZigBee communication module and IMU sensor module then run at full speed to collect and report positioning data at a normal frequency.

[0230] In some embodiments, the following steps are also included:

[0231] When the location tag is in deep sleep mode, it periodically wakes up the Zigbee communication module to send a heartbeat packet to the platform layer.

[0232] To prevent the system from "freezing," a timer interrupt needs to be set in deep sleep mode to wake up the system periodically and send a heartbeat packet to the backend server to indicate that the server is "fault-free."

[0233] Finally, it should be noted that although the above embodiments have been described in the text and drawings of this application, this should not limit the scope of patent protection of this application. Any technical solutions that are based on the essential concept of this application and utilize the content described in the text and drawings of this application, resulting in equivalent structural or procedural substitutions or modifications, as well as the direct or indirect application of the technical solutions of the above embodiments to other related technical fields, are all included within the scope of patent protection of this application.

Claims

1. A Zigbee-based positioning system for fabric carts in dyeing plants, characterized in that, include: The perception layer includes multiple positioning tags, which are installed on the dyeing plant's fabric cart. Each positioning tag includes an IMU sensor module, a Zigbee communication module, and a battery system. The IMU sensor module is used to acquire the pose data of the dyeing plant's fabric cart, the Zigbee communication module is used to acquire the Zigbee positioning signal and wireless communication of the dyeing plant's fabric cart, and the battery system is used to power the sensor module and the Zigbee communication module. The network layer includes Zigbee base stations and factory local area networks, and is used for data transmission between the perception layer and the platform layer. The platform layer is used to obtain the relative displacement and heading angle of the dyeing plant fabric cart based on the pose data of the dyeing plant fabric cart when the position of the dyeing plant fabric cart changes, and to obtain the absolute position of the dyeing plant fabric cart based on the Zigbee positioning signal of the dyeing plant fabric cart. The calculated relative displacement and absolute position are fused to obtain the positioning result of the dyeing plant fabric cart, and the positioning result of the dyeing plant fabric cart is sent to the application layer. The application layer is used to visualize the positioning results of the dyeing plant fabric cart sent by the platform layer.

2. The Zigbee-based dyeing plant fabric cart positioning system according to claim 1, characterized in that, The IMU sensor module includes an accelerometer and a gyroscope. Specifically, the platform layer is used to collect the mixed acceleration of the dyeing plant fabric cart through the accelerometer and the angular velocity of the dyeing plant fabric cart through the gyroscope when the dyeing plant fabric cart is moving. The collected mixed acceleration is subtracted from the gravitational acceleration vector to obtain the motion acceleration. The motion acceleration is integrated once to obtain the velocity. It is then determined whether the dyeing plant fabric cart is stationary. If it is stationary, the velocity is integrated once to obtain the relative displacement of the dyeing plant fabric cart. The angular velocity is integrated to obtain the heading angle of the dyeing plant fabric cart.

3. The Zigbee-based dyeing plant fabric cart positioning system according to claim 2, characterized in that, The platform layer is also used to calculate the current acceleration variance and angular velocity variance of the dyeing plant's fabric cart. When the acceleration variance is less than the acceleration variance threshold and the angular velocity variance is less than the angular velocity variance threshold, it is determined that the current dyeing plant's fabric cart is in a stationary state.

4. The Zigbee-based dyeing plant fabric cart positioning system according to claim 1, characterized in that, The platform layer is specifically used to calculate the relative displacement of the dyeing plant fabric cart based on the pose data collected by the IMU sensor module, then to obtain the filtered relative displacement by high-frequency filtering, and to obtain the filtered absolute position by low-pass filtering of the absolute position of the dyeing plant fabric cart calculated based on the Zigbee signal according to the memory coefficient, and finally to obtain the positioning result of the dyeing plant fabric cart by fusing the filtered relative displacement and the filtered absolute position.

5. The Zigbee-based dyeing plant fabric cart positioning system according to claim 1, characterized in that, The positioning tag is also used to enter a deep sleep mode when the dyeing plant's fabric cart remains stationary for a preset time, thereby shutting down the Zigbee communication module and controlling the IMU sensor module to operate at a preset power consumption. When the IMU sensor detects that the acceleration exceeds a preset threshold, it wakes up the Zigbee communication module and controls the IMU sensor module to operate at normal power.

6. The Zigbee-based dyeing plant fabric cart positioning system according to claim 5, characterized in that, The location tag is also used to periodically wake up the Zigbee communication module and send a heartbeat packet to the platform layer when in deep sleep mode.

7. The Zigbee-based dyeing plant fabric cart positioning system according to claim 1, characterized in that, The platform layer is also used to divide the high-precision digital map of the dyeing factory area into several grids, obtain the markers of each grid, the markers include walkable or non-walkable, perform pixel dilation on the grid areas marked as non-walkable, fuse the calculated relative displacement and absolute position to obtain the position coordinates of the dyeing factory's fabric carts and place them on the map. If the position coordinates are in the walkable area, the position coordinates are taken as the final positioning result. If the position coordinates are in the non-walkable area, the search radius is expanded with the position coordinates as the center until a grid marked as walkable is found, and the center position of the grid is taken as the positioning result for this time.

8. A Zigbee-based method for positioning fabric carts in a dyeing plant, wherein the method is applied to the Zigbee-based positioning system for fabric carts in a dyeing plant as described in any one of claims 1-7, characterized in that... The method includes the following steps: When the positioning tag on the dyeing plant fabric cart detects that the dyeing plant fabric cart has entered the running state, it collects the pose data of the dyeing plant fabric cart through the IMU sensor module and obtains the Zigbee positioning signal of the dyeing plant fabric cart through the Zigbee communication module. The collected pose data and Zigbee positioning signals of the dyeing factory's fabric carts are sent to the platform layer; The platform layer obtains the relative displacement and heading angle of the dyeing plant fabric cart based on its pose data, and obtains the absolute position of the dyeing plant fabric cart based on its Zigbee positioning signal. The calculated relative displacement and absolute position are then fused to obtain the positioning result of the dyeing plant fabric cart. The location results of the dyeing plant's fabric carts are sent to the application layer for visualization.

9. The Zigbee-based dyeing plant fabric cart positioning method according to claim 8, characterized in that, The IMU sensor module includes an accelerometer and a gyroscope. The platform layer obtains the relative displacement and heading angle of the dyeing plant fabric cart based on its pose data, specifically including the following steps: The acceleration sensor collects the mixed acceleration of the dyeing factory's fabric cart, and subtracts the gravitational acceleration vector to obtain the motion acceleration; The velocity is obtained by integrating the acceleration. Determine whether the dyeing plant fabric cart is stationary. If it is stationary, integrate the velocity to obtain the relative displacement of the dyeing plant fabric cart, and integrate the angular velocity to obtain the heading angle of the dyeing plant fabric cart.

10. The Zigbee-based dyeing plant fabric cart positioning method according to claim 8, characterized in that, The process of fusing the calculated relative displacement and absolute position to obtain the positioning result of the dyeing plant fabric cart specifically includes the following steps: The platform layer divides the high-precision digital map of the dyeing plant area into several grids and obtains the markers for each grid, including whether it is walkable or not walkable. Perform pixel dilation on grid regions marked as unwalkable; The calculated relative displacement and absolute position are fused together to obtain the position coordinates of the dyeing factory's fabric cart, which are then placed on the map. If the location coordinates are within the walkable area, then the location coordinates are taken as the final location result; If the location coordinates are in an unwalkable area, expand the search radius using the location coordinates as the center until a walkable grid is found, and use the center of that grid as the location result for this operation.

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