An intelligent cabinet and method based on weight adaptive radio frequency power adjustment

Abstract

The application discloses an intelligent cabinet and method based on weight self-adaptive radio frequency power adjustment, which comprises a cabinet body, a plurality of drawer modules, a precision weighing module, an RFID module and a man-machine interaction host.The drawer modules are arranged in the cabinet body.The precision weighing module comprises a weighing sensor and a weight data acquisition module, and digital weight data W is obtained.The RFID module comprises an RFID host and an RFID antenna, which are connected through an RFID feeder line, and the RFID electronic tags of the articles in the drawer modules are identified.The RFID module receives external instructions.The man-machine interaction host reads the weight data W of the articles in the drawer modules in real time, adjusts the radio frequency transmission power of the RFID host and controls the radio frequency radiation intensity of the RFID antenna.

Description

Technical Field

[0001] This invention belongs to the field of intelligent drug storage and radio frequency identification technology, and relates to a technology for controlling narcotic and psychotropic drugs by adjusting the RFID radio frequency transmission power in real time through precise weighing data feedback. Background Technology

[0002] Fentanyl-related drugs are strictly controlled narcotic and psychotropic substances in China. Their storage, warehousing, and inventory management must comply with the stringent requirements of relevant regulations, including GA / T 2015-2023 General Technical Specifications for Intelligent Cabinets Dedicated to Fentanyl-Related Drugs. To achieve standardized storage and full-process traceability management of these controlled drugs, medical institutions, surgical centers, central pharmacies, and pharmacy departments are generally equipped with intelligent cabinets dedicated to fentanyl-related drugs.

[0003] Existing smart cabinets specifically designed for fentanyl-related drugs typically have RFID antennas installed in drawers or medicine boxes to perform radio frequency identification on RFID electronic tags attached to the drugs or their packaging, enabling automatic inventory counting and verification of drug entry and exit. Some smart cabinets also add weighing sensors to the bottom of the drawers to supplement the measurement of the total weight of the drugs inside, and then verify the quantity against the RFID identification results.

[0004] The radio frequency transmission power of the RFID antenna inside the drawer is usually a fixed value preset by the factory. When the number of medicines in the drawer is small and the RFID tags are sparsely distributed, the excessively high fixed radio frequency power will penetrate the drawer partition and read RFID tags from adjacent drawers or outside the drawer, causing cross-drawer reading errors. When the number of medicines in the drawer is large and they are densely stacked in multiple layers, the medicines and tags block and absorb each other, resulting in significant attenuation of the radio frequency signal, missed readings, and inaccurate identification of all medicines in the drawer.

[0005] The RF transmission power is preset using manual experience or factory default values, making it difficult to adaptively adjust to dynamic changes in the loading status of medicines in the drawer after installation. It cannot handle both empty and full-load extreme conditions, and is difficult to adapt to diverse scenarios where medicines in different packaging forms such as ampoules, vials, plastic bottles, and tablets are mixed.

[0006] The weighing data from the smart cabinet with weighing function serves as an independent quantity verification basis for the RFID identification results. The two identification methods are merely parallel, failing to establish a data-level linkage control mechanism. The weighing module does not provide active feedback control for the RFID identification process, thus losing the opportunity to dynamically optimize RFID performance using weight information. This results in significant deficiencies in the smart cabinet's identification accuracy, anti-interference capability, and compliance traceability. Summary of the Invention

[0007] This invention provides a smart cabinet based on weight-adaptive radio frequency power adjustment. It integrates a precision weighing module and an RFID module in the drawer module. Based on the total weight data of the medicines in the drawer, it controls the radio frequency transmission power of the RFID antenna in real time to automatically match the loading amount of medicines in the drawer.

[0008] This invention overcomes the shortcomings of existing intelligent cabinets, such as fixed radio frequency power and lack of adaptability to changes in loading volume; it solves the problem of RFID tags being missed due to obstruction when a large amount of medicine is loaded; it solves the problem of misreading across drawers and cross-reading of adjacent drawer tags due to excessive radio frequency power when a small amount of medicine is loaded; it breaks the existing situation where weighing and RFID identification methods are independent of each other, and establishes a data linkage feedback control mechanism between the two; it improves the accuracy and reliability of inventory identification of controlled drugs, and meets the compliance requirements of drug traceability accuracy for closed-loop drug management.

[0009] The smart cabinet includes a cabinet body, several drawer modules, a precision weighing module, an RFID module, and a human-machine interaction host.

[0010] The drawer modules are located inside the cabinet and are used to store items.

[0011] The drawer module is automatically opened and closed by an electric drawer opening and closing system.

[0012] The precision weighing module includes a weighing sensor and a weight data acquisition module. The weighing sensor is located at the bottom of the drawer module and measures the weight of the items inside the drawer module in real time. The weight AD analog signal is sent to the weight data acquisition module, which amplifies, filters, and converts the signal from analog to digital to obtain the digital weight data W.

[0013] The RFID module includes an RFID host and an RFID antenna, which are connected via an RFID feeder. The RFID antenna is located inside the drawer module to identify the RFID electronic tags of items inside the drawer module. The RFID host has an interface to receive external commands and dynamically adjust the radio frequency transmission power.

[0014] The human-machine interface host communicates with the weight data acquisition module via the ModBus-RTU bus to read the weight data W of the items in the drawer module in real time; it also communicates with the RFID host via the RS232 serial bus to dynamically send RF transmission power setting commands based on the weight data W, thereby adjusting the RF transmission power of the RFID host and controlling the RF radiation intensity of the RFID antenna.

[0015] The human-computer interaction host has a pre-stored function f(W), which represents the mapping relationship between weight data W and radio frequency transmission power P, P = f(W).

[0016] f(W) is a monotonically increasing function, and the transmit power P of the radio frequency signal increases as the weight data W increases.

[0017] The function f(W) is established by calibration experiments to create a lookup table, or by using a piecewise linear function or an exponential function.

[0018] The smart cabinet also includes a touch screen, an identity recognition module, a medicine location light indicator system, a UPS uninterruptible power supply, and a cabinet control program for managing the smart cabinet.

[0019] Step 1: The weighing sensor collects the AD analog signal of the weight of the items in the drawer module in real time, sends it to the weight data acquisition module to be converted into digital weight data W, and sends it to the human-machine interface host via the ModBus-RTU bus.

[0020] Step 2: The human-computer interaction host calculates the radio frequency transmission power P of the current RFID scan based on the weight data W and the pre-stored mapping relationship P = f(W).

[0021] Step 3: The human-machine interface host sends a power setting command to the RFID host via the RS232 bus to adjust the RFID host's radio frequency transmission power to P.

[0022] Step four: The RFID host drives the RFID antenna to transmit radio frequency signals according to the radio frequency transmission power P, identifies the RFID electronic tags of the items in the drawer module, and sends the tag information to the human-machine interaction host through the RS232 bus.

[0023] Step 5: The human-computer interaction host cross-validates the tag information with the weight data W. It calculates the theoretical weight based on the unit weight of the item and the number of items identified. If the difference between the theoretical weight and the actual weight data W is within the preset range, the identification is deemed valid. Otherwise, an abnormal alarm is triggered, prompting a rescan. The inventory results are then output and sent to external systems, such as reporting data through the hospital HIS system interface and the public security system interface.

[0024] The RFID identification accuracy of this invention is significantly improved: by using the actual weight of the medicine in the drawer as the feedback signal, the radio frequency transmission power of the RFID antenna is dynamically adjusted, which effectively avoids missed readings caused by tag obstruction when the medicine is loaded, and cross-drawer misreads and cross-reads caused by excessive power when the medicine is loaded.

[0025] This invention achieves linkage feedback control between weighing and RFID: In the prior art, weighing and RFID are only used as independent verification methods. This invention is the first to make weighing data the active control source of RFID radio frequency power, forming a closed-loop control link of weighing-power-identification. The two identification methods are upgraded from simple parallel to linkage and complementarity, and the reliability is significantly enhanced.

[0026] This invention automatically adapts to various loading conditions: without the need for manual adjustment of radio frequency power based on the quantity of drugs, the system automatically adapts to various loading states from empty to full load, and from small quantities to dense stacking, based on weight, and is compatible with fentanyl drugs in various packaging forms such as ampoules, vials, plastic bottles, and tablets.

[0027] This invention reduces radio frequency cross-interference in multi-drawer structures: by transmitting on demand to adapt to the minimum necessary power currently loaded, radio frequency leakage and cross-interference to adjacent drawer areas are minimized, thereby improving the stability and independence of the overall identification of multi-drawer smart cabinets.

[0028] This invention is highly compliant and easy to promote: it meets the requirements of "GA / T 2015-2023 General Technical Specifications for Intelligent Cabinets for Fentanyl Drugs" for drug identification accuracy and traceability, and helps to manage the entire process of controlled narcotic and psychotropic drugs in a closed loop.

[0029] The invention has a clear architecture and is simple to implement: it adopts the mature ModBus-RTU industrial fieldbus and RS232 serial bus as the main communication interfaces, with low hardware cost, high reliability, easy integration and maintenance, and easy to upgrade and transform based on existing intelligent cabinet products. Detailed Implementation

[0030] Taking a smart cabinet for storing fentanyl-type drugs as an example, the present invention will be described in further detail.

[0031] The entire unit adopts a vertical cabinet structure, and the main frame is made of aviation aluminum 5052-F, with dimensions of 1700mm×1020mm×545mm.

[0032] The cabinet is equipped with 8 drawer modules. Some drawer modules are used for storing medicines, while others are used for recycling empty bottles and residual liquids.

[0033] A strain gauge-type high-precision load cell is installed at the bottom of the drawer module, with a weighing accuracy of ±5g. It outputs a weight AD analog signal, which is sent to the weight data acquisition module through a shielded wire.

[0034] The weight data acquisition module has a built-in 24-bit ADC chip and an STM32 series microcontroller. It filters, amplifies, and converts the AD signal from analog to digital, and outputs digital weight data W. The data is then sent to the human-machine interface host via the ModBus-RTU bus in RS485 physical layer, 9600bps baud rate, and 8N1 data frame format.

[0035] The RFID antenna of the RFID module is located on the top or side of the drawer module. It uses a directional flat panel antenna with a UHF band frequency of 902MHz to 928MHz and is connected to the RFID host through a 50Ω coaxial radio frequency RFID feeder.

[0036] The RFID host uses a UHF reader with EPC Gen2 protocol, which has an adjustable radio frequency transmission power of 0 to 30dBm in 1dBm steps. It communicates with the human-machine interface host through RS232 serial bus with an RS232 communication baud rate of 115200bps.

[0037] The human-computer interaction host uses an industrial control computer with a CPU RK3568 and 8.0GB of memory, runs the Android 12 / HarmonyOS operating system, and is equipped with a 17.3-inch 1920×1080 resolution touch screen. It connects to the hospital's HIS system and the national traceability and control platform for narcotic and psychotropic drugs through RJ45 Ethernet port, Wifi, and 4G / 5G network.

[0038] The human-computer interaction host has a pre-stored weight and power mapping table. The mapping relationship f(W) is set as a piecewise function with units of g→dBm, which is obtained through no-load and full-load calibration tests before leaving the factory.

[0039] When W < 50g, P = 10dBm; when 50g ≤ W < 200g, P = 15dBm; when 200g ≤ W < 500g, P = 20dBm; when 500g ≤ W < 1000g, P = 25dBm; when W ≥ 1000g, P = 30dBm.

[0040] The specific values ​​are calibrated and adjusted based on parameters such as antenna radiation pattern, drawer size, and drug packaging material, and stored in the configuration file of the human-computer interaction host.

[0041] Operators complete multi-factor authentication and identification using facial recognition, fingerprints, ID cards, passwords, etc., and initiate outbound or inventory operations. The drawer module automatically opens under the drive of the electric drawer opening and closing system.

[0042] The weighing sensor measures the weight of the medicine in the current drawer module in real time. The weight data acquisition module converts the weight AD signal into digital weight data W, which is then sent to the human-machine interface host via the ModBus-RTU bus.

[0043] The human-machine interface host receives W, calculates the radio frequency power P according to the preset mapping table f(W), and sends a power setting command to the RFID host via the RS232 bus, for example, AT command form AT+POWER= \r\n.

[0044] Upon receiving the instruction, the RFID host sets the radio frequency power to P, initiates the RFID tag scanning process, drives the RFID antenna to transmit radio frequency signals, polls and identifies all RFID electronic tags in the drawer module, and sends the identified tag EPC code, drug batch number, specifications and other information to the human-machine interface host via RS232 bus.

[0045] The human-computer interaction host cross-validates the RFID identification result with the weight data W. It calculates the theoretical weight based on the unit weight of the medicine and the number of identifications. If the difference between the theoretical weight and the actual weight data W is within the preset range, the identification is deemed valid. Otherwise, an abnormal alarm is triggered, prompting a rescan.

[0046] After the drawer is closed, the human-computer interaction host generates an operation record, which is uploaded to the hospital's HIS system and the national traceability and control platform for narcotic and psychotropic drugs through a network interface, realizing closed-loop traceability management throughout the entire process.

[0047] Compared to the control scheme with a fixed RF power of 25dBm, the weight-adaptive RF power adjustment scheme provided by this invention reduces the cross-drawer misread rate from approximately 3% to 5% to below 0.1% under no-load conditions (W < 50g); and under full-load conditions (W ≥ 1000g), the tag miss rate reduces from approximately 2% to 4% to below 0.2%, and the overall identification accuracy increases from 95% to over 99.5%, meeting the stringent requirements for drug identification accuracy and full-process traceability of fentanyl-class controlled drugs.

Claims

1. A smart cabinet based on weight-adaptive radio frequency power adjustment, characterized in that, include: The system comprises a cabinet, several drawer modules, a precision weighing module, an RFID module, and a human-machine interface host. The drawer modules are located inside the cabinet and store items. The precision weighing module includes a weighing sensor and a weight data acquisition module. The weighing sensor is located at the bottom of the drawer module and measures the weight of the items inside in real time, sending the analog weight signal to the weight data acquisition module. After amplification, filtering, and analog-to-digital conversion, the digitized weight data W is obtained. The RFID module includes an RFID host and an RFID antenna connected via an RFID feeder. The RFID antenna is located inside the drawer module and identifies the RFID tags on the items inside. The RFID host has an interface to receive external commands and dynamically adjust the radio frequency transmission power. The human-machine interface host communicates with the weight data acquisition module via a ModBus-RTU bus to read the weight data W of the items in the drawer module in real time. It also communicates with the RFID host via an RS232 serial bus, dynamically sending radio frequency transmission power setting commands based on the weight data W to adjust the RFID host's radio frequency transmission power and control the radio frequency radiation intensity of the RFID antenna.

2. The intelligent cabinet based on weight-adaptive radio frequency power adjustment according to claim 1, characterized in that, The drawer module is automatically opened and closed by an electric drawer opening and closing system.

3. The intelligent cabinet based on weight-adaptive radio frequency power adjustment according to claim 1, characterized in that, The pre-stored function f(W) of the human-computer interaction host represents the mapping relationship between weight data W and radio frequency transmission power P, P = f(W).

4. The intelligent cabinet based on weight-adaptive radio frequency power adjustment according to claim 3, characterized in that, The function f(W) is a monotonically increasing function, and the transmit power P of the radio frequency signal increases as the weight data W increases.

5. The intelligent cabinet based on weight-adaptive radio frequency power adjustment according to claim 4, characterized in that, The function f(W) is established by calibration experiments using a lookup table, a piecewise linear function, or an exponential function.

6. The intelligent cabinet based on weight-adaptive radio frequency power adjustment according to claim 1, characterized in that, The smart cabinet also includes: a touch screen, an identity recognition module, a medicine location light indicator system, a UPS uninterruptible power supply, and a cabinet control program for managing the smart cabinet.

7. A method for weight-adaptive radio frequency power regulation, characterized in that, The intelligent cabinet based on weight-adaptive radio frequency power adjustment according to claim 3 comprises: Step 1: The weighing sensor collects the AD analog signal of the weight of the items in the drawer module in real time, sends it to the weight data acquisition module to be converted into digital weight data W, and sends it to the human-machine interface host through the ModBus-RTU bus; Step 2: The human-computer interaction host calculates the radio frequency transmission power P of the current RFID scan based on the weight data W and the pre-stored mapping relationship P = f(W); Step 3: The human-machine interface host sends a power setting command to the RFID host via the RS232 bus to adjust the RFID host's radio frequency transmission power to P; Step four: The RFID host drives the RFID antenna to transmit radio frequency signals according to the radio frequency transmission power P, identifies the RFID electronic tags of the items in the drawer module, and sends the tag information to the human-machine interaction host through the RS232 bus.

8. The method for weight-adaptive radio frequency power regulation according to claim 7, characterized in that, It also includes: Step 5, the human-computer interaction host cross-validates the tag information with the weight data W, calculates the theoretical weight based on the unit weight of the item and the number of items identified, and if the difference between the theoretical weight and the actual weight data W is within the preset range, the identification is deemed valid; otherwise, an abnormal alarm is triggered.