Method for reducing label identification outside RFID intelligent storage cabinet

Abstract

The invention relates to the technical field of RFID (Radio Frequency Identification) systems, in particular to a method for reducing tag identification outside an RFID intelligent storage cabinet, and aims to solve the problem of inconvenient article management caused by the fact that tags inside and outside the cabinet cannot be accurately distinguished due to the problem of radio frequency signal coverage of an existing RFID reader-writer. The space is X (1m < = X < = 2m), and indicating labels are arranged in the cabinets. The reader-writer transmits radio frequency signals with specific frequency (860-960MHz) at P1 and P2, measures the phase difference between the electronic tag and the indication tag, and judges whether the tag is in the cabinet or not according to a set difference value theta. And testing the shielding effect of the cabinet door before starting, and judging the shielding effect according to the difference percentage Y of the theoretical phase difference and the actually measured phase difference influence value. According to the method, the label position can be effectively judged, stable operation of the system is ensured, and the accuracy of identifying articles in the cabinet by the RFID intelligent storage cabinet is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of RFID systems, and in particular to a method for reducing the recognition of tags outside an RFID intelligent storage cabinet. Background Art

[0002] RFID smart storage cabinets use electronic tags to identify stored items, and quickly scan and read tag information through readers and writers to achieve automated management of items, greatly improving the efficiency of item storage and retrieval.

[0003] In practical applications, each item is typically tagged and placed in an RFID smart storage cabinet. However, a significant issue currently exists: the RFID reader's radio frequency signal has a limited coverage range. If other cabinets or items are located near a designated cabinet, the reader's signal may misinterpret the electronic tags of items inside or outside the cabinet when scanning the designated cabinet. When scanning and reading, the reader cannot accurately distinguish which items have electronic tags inside and outside the designated cabinet. This inability to distinguish between tags inside and outside the cabinet creates significant inconvenience in actual item management.

[0004] In order to solve this problem and improve the accuracy of RFID smart storage cabinets in identifying items inside the cabinet, it is of great practical significance to develop a method that can effectively reduce the recognition of RFID smart storage cabinets' external tags. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and method for reducing the identification of tags outside the RFID smart storage cabinet to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A method for reducing the identification of tags outside an RFID smart storage cabinet includes the following identification steps:

[0008] S1. Scan point setting and indicator label setting:

[0009] Two scanning points P1 and P2 are set in sequence on the central axis in front of the storage cabinet door, with a distance X between P1 and P2; an indicator label is set inside the storage cabinet;

[0010] S2. Signal transmission:

[0011] Use the reader to transmit radio frequency signals at points P1 and P2 respectively. The frequency of the radio frequency signal transmitted by the reader is f.

[0012] S3. Phase difference detection:

[0013] Measure the phases φ1 and φ2 of the electronic tag and the phases φ3 and φ4 of the indicator tag at points P1 and P2 respectively;

[0014] S4. Modeling and determination of indication phase difference:

[0015] Calculate the actual phase difference φactual=|φ2-φ1|;

[0016] Calculate the indicator tag phase difference φindicator=|φ4-φ3|;

[0017] Set the difference value θ. When φactual satisfies |φactual-φindicated| / φindicated≤θ, the tag is determined to be inside the cabinet; otherwise, the tag response is blocked.

[0018] As a preference, θ is 15%, and when φ actual satisfies |φ actual - φ indication| / φ indication ≤ 15%, it is determined that the tag is located in the cabinet; otherwise, the tag response is shielded.

[0019] Preferably, 1m≤X≤2m; the frequency f of the radio frequency signal emitted by the reader is between 860-960MHz.

[0020] As a preference, before starting the identification step, the shielding effect of the storage cabinet door is tested, and the test value is entered into the data processing system where the reader is located. The test steps are as follows:

[0021] Step 1: Install test electronic tags on the inner and outer walls of the storage cabinet door;

[0022] Step 2: Use the reader to transmit radio frequency signals at points P1 and P2 respectively. The frequency of the radio frequency signal transmitted by the reader is f.

[0023] Step 3: Measure the phases of the electronic tag on the inner wall of the cabinet door at points P1 and P2 (φ test 1 and φ test 2), and measure the phases of the electronic tag on the outer wall of the cabinet door at points P1 and P2 (φ test 3 and φ test 4).

[0024] Step 4: Calculate the effect of the cabinet door on the phase difference φ cabinet door;

[0025] The calculation formula is φ cabinet door = (|φ test 1 + φ test 2 - φ test 3 - φ test 4|) / 2

[0026] As a preferred method, according to the scanning point spacing X and the RF signal wavelength λ (λ = c / f, c is the speed of light), the theoretical phase difference φ theoretical = 2πX / λ is calculated by calculating the electronic tag on the outer wall of the door P1 and P2;

[0027] Set the difference percentage Y, (φtheoretical - φdoor) ≤ Y to determine that the door shielding effect is normal and the tag position is valid; otherwise, an alarm is triggered to indicate that the shielding is invalid.

[0028] As a preference, Y=5%, when (φtheoretical-φcabinet door)≤5%, it is determined that the cabinet door shielding effect is normal and the indication tag position is valid; otherwise, an alarm is triggered to prompt that the shielding is invalid.

[0029] The beneficial effects of the present invention compared to the prior art are as follows:

[0030] 1. Existing RFID readers cannot accurately distinguish between tags inside and outside the cabinet due to radio frequency signal coverage issues, leading to inconvenience in item management. This invention establishes two scanning points on the central axis directly in front of the cabinet door and places an indicator tag inside the cabinet. The correlation between the phase difference of electronic tags at different locations and the phase difference of the indicator tag is measured to determine whether a tag is inside the cabinet.

[0031] 2. Appropriate scanning point spacing and RF signal frequency can ensure the accuracy and stability of phase difference measurement, making the tag position determination method based on phase difference more reliable.

[0032] 3. Before initiating the identification process, the present invention comprehensively tests the cabinet door's shielding effectiveness. By placing test electronic tags on the inner and outer walls of the door and measuring the phase of the test tags at different locations, the system determines whether the door's shielding is functioning properly and indicates that the tag position is valid. This method ensures the long-term stability of the system, ensures the reliability of the phase difference-based tag identification method, and further improves the accuracy and stability of RFID smart cabinet identification of items within the cabinet. DETAILED DESCRIPTION

[0033] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0034] The following is a specific embodiment of a method for reducing the number of tags recognized outside an RFID smart storage cabinet:

[0035] Example 1

[0036] Scene setting and hardware preparation:

[0037] In a library's RFID smart storage cabinet system, each cabinet is used to store items temporarily stored by readers. One of the standard-sized cabinets is selected to implement this method.

[0038] Set two scanning points P1 and P2 on the central axis in front of the designated storage cabinet door, with the distance between P1 and P2 being X (1m≤X≤2m; for example, 1m, 1.5m, 2m).

[0039] Set an instruction label at a fixed location inside the storage cabinet (such as the center of the back wall).

[0040] Adjust the reader's RF signal so that the frequency is between 860MHz and 960MHz.

[0041] Identification steps performed:

[0042] Signal transmission: A reader / writer is used to transmit a radio frequency signal with a frequency of 915 MHz at points P1 and P2 (a radio frequency signal of 915 MHz is used in this embodiment).

[0043] Phase difference detection: The electronic tag's phases φ1 and φ2, as well as the indicator tag's phases φ3 and φ4, are measured at points P1 and P2, respectively. The measurements show φ1 = 28°, φ2 = 50°, φ3 = 10°, and φ4 = 30°.

[0044] Indicator phase difference modeling and judgment:

[0045] φactual=|50°-28°|=22°.

[0046] φ indication = |30°-10°| = 20°.

[0047] Set the difference value θ=15, calculate |φactual-φindicated| / φindicated=(22-20) / 20=10%<15%, and determine that the tag is located in the cabinet. The reader reads the tag information normally.

[0048] Before applying the system, the shielding effect of the cabinet door can be tested and the test data can be recorded into the reader's processing system to determine whether the cabinet door is normal:

[0049] The test steps are as follows:

[0050] Test electronic tags are respectively set on the inner and outer side walls of the cabinet door.

[0051] Use the reader to transmit a 915MHz radio frequency signal at points P1 and P2 respectively.

[0052] The phases of the electronic tags on the inner wall of the cabinet door are measured at points P1 and P2, with φ test 1 = 25° and φ test 2 = 45°. The phases of the electronic tags on the outer wall of the cabinet door are measured at points P1 and P2, with φ test 3 = 10° and φ test 4 = 30°.

[0053] Calculate the effect of the cabinet door on the phase difference: φdoor = |φtest1+φtest2-φtest3-φtest4| / 2 = (|25°+45°-10°-30°|) / 2 = 15°.

[0054] Based on the scanning point spacing X = 1.5m and the RF signal wavelength λ = c / f = 0.328m, the theoretical phase difference between the two electronic tags P1 and P2 on the outer wall of the cabinet door is calculated as φtheoretical = 2πX / λ≈28.7°.

[0055] Set the difference percentage Y = 5%, calculate φtheoretical - φcabinet door = 28.7° - 15° = 13.7°, 13.7 / 28.7>5%, triggering an alarm to indicate shielding failure. At this time, the staff can check and repair the shielding performance of the cabinet door to ensure the normal operation of the system.

[0056] Example 2

[0057] Scene setting and hardware preparation:

[0058] In a large warehousing and logistics center, select an RFID smart storage cabinet for storing electronic products.

[0059] Two scanning points P1 and P2 are set on the central axis in front of the storage cabinet door, with a distance of X = 1m.

[0060] An instruction label is provided on the top wall of the storage cabinet.

[0061] The frequency of the radio frequency signal transmitted by the reader is f=860MHz.

[0062] Identification steps performed:

[0063] Signal transmission: The reader transmits a radio frequency signal with a frequency of 860MHz at points P1 and P2.

[0064] Phase difference detection: The measured phases of the electronic tag are φ1 = 40°, φ2 = 65°, and the phases of the indicator tag are φ3 = 15°, φ4 = 41°.

[0065] Indicator phase difference modeling and judgment:

[0066] The actual phase difference φactual is calculated as: |φ2-φ1|=|65°-40°|=25°.

[0067] The calculated indication tag phase difference φindication=|φ4-φ3|=|41°-15°|=26°.

[0068] Since (φactual−φindication) / φindication 0<difference value θ, where θ=15, it is determined that the tag is inside the cabinet, and the reader / writer processes the tag information normally.

[0069] Cabinet door shielding effect test:

[0070] Test step execution:

[0071] Test electronic tags are set on the inner and outer walls of the cabinet door.

[0072] The reader transmits a radio frequency signal with a frequency of 860MHz at points P1 and P2.

[0073] The phases of the electronic tag on the inner wall of the cabinet door were measured as φ test 1 = 30°, φ test 2 = 50°, and the phases of the electronic tag on the outer wall of the cabinet door were measured as φ test 3 = 12°, φ test 4 = 33°.

[0074] Calculate φ cabinet door = |φ test 1 + φ test 2 - φ test 3 - φ 4| / 2 = |30°+50°-12°-33°| / 2 = 17.5°.

[0075] Based on the scanning point spacing X = 1m and the RF signal wavelength λ = c / f = 0.349m, the theoretical phase difference between the two electronic tags P1 and P2 on the outer wall of the cabinet door is calculated as φtheoretical = 2πX / λ≈18°.

[0076] Because |φtheoretical-φcabinet door=|18°-17.5°=0.5°, 0.5 / 18≈2.8<difference percentage Y(5%), no alarm is triggered, indicating that the cabinet door shielding effect is normal, the indication tag position is valid, and the system can operate stably for tag recognition.

[0077] It can be seen from the above two embodiments that the present invention determines whether the tag is in the cabinet by setting two scanning points on the central axis just in front of the storage cabinet door, and setting an indicator tag in the cabinet, measuring the correlation between the phase difference of the electronic tags at different positions and the phase difference of the indicator tag. Appropriate scanning point spacing and radio frequency signal frequency can ensure the accuracy and stability of the phase difference measurement, making the tag position determination method based on phase difference more reliable. Before starting the identification step, the present invention conducts a comprehensive test on the shielding effect of the storage cabinet door. By setting test electronic tags on the inner and outer walls of the cabinet door, measuring the phase of the test electronic tags at different positions, judging whether the cabinet door shielding effect is normal, and indicating the tag position is valid; the present invention ensures the long-term stable operation of the system, ensures the reliability of the tag identification method based on phase difference, and further improves the accuracy and stability of the RFID smart storage cabinet in identifying items in the cabinet.

Claims

1. A method for reducing the number of tags identified outside an RFID smart storage cabinet, characterized in that: The identification steps include: S1. Scan point setting and indicator label setting: Two scanning points P1 and P2 are set in sequence on the central axis in front of the storage cabinet door, with a distance X between P1 and P2; an indicator label is set inside the storage cabinet; S2. Signal transmission: Use the reader to transmit radio frequency signals at points P1 and P2 respectively. The frequency of the radio frequency signal transmitted by the reader is f. S3. Phase difference detection: Measure the phases φ1 and φ2 of the electronic tag and the phases φ3 and φ4 of the indicator tag at points P1 and P2 respectively; S4. Modeling and determination of indication phase difference: Calculate the actual phase difference φ 实际 =|φ2-φ1|; Calculate the phase difference φ of the indicator tag 指示 =|φ4-φ3|; Set the difference value θ, when φ 实际 Satisfy |φ 实际 -φ 指示 | / φ 指示 When ≤θ, the tag is determined to be inside the cabinet; otherwise, the tag response is blocked.

2. The method of reducing RFID smart storage cabinet external tag recognition according to claim 1, characterized in that: θ is 15%, when φ 实际 Satisfy |φ 实际 -φ 指示 | / φ 指示 ≤15%, the tag is determined to be inside the cabinet; otherwise, the tag response is blocked.

3. The method of reducing RFID smart storage cabinet external tag recognition according to claim 1, characterized in that: 1m≤X≤2m; the frequency f of the radio frequency signal emitted by the reader is between 860-960MHz.

4. The method of reducing RFID smart storage cabinet external tag recognition according to claim 1, characterized in that: Before starting the identification process, the shielding effect of the storage cabinet door is tested and the test value is recorded in the data processing system where the reader is located. The test steps are as follows: Step 1: Install test electronic tags on the inner and outer walls of the storage cabinet door; Step 2: Use the reader to transmit radio frequency signals at points P1 and P2 respectively. The frequency of the radio frequency signal transmitted by the reader is f. Step 3: Measure the phase φ of the electronic tag on the inner wall of the cabinet door at points P1 and P2. 测试1 and φ 测试2 , measure the phase φ of the electronic tag on the outer wall of the cabinet door at points P1 and P2 测试3 and φ 测试4 , Step 4: Calculate the effect of the cabinet door on the phase difference φ 柜门 ; The calculation formula is φ cabinet door = (|φ 测试1 +φ 测试2 -φ 测试3 -φ 测试4 |) / 2.

5. The method for reducing the number of tags identified outside an RFID smart storage cabinet according to claim 4, wherein: According to the scanning point spacing X and the RF signal wavelength λ (λ = c / f, c is the speed of light), the theoretical phase difference φ between points P1 and P2 on the outer wall of the cabinet door is calculated. 理论 =2πX / λ; Set the difference percentage Y, (φ 理论- φ 柜门 )≤Y, the cabinet door shielding effect is normal and the indicator tag position is valid; otherwise, an alarm is triggered to prompt that the shielding is invalid.

6. The method of reducing RFID smart storage cabinet external tag recognition according to claim 5, characterized in that: Y=5%, when (φ 理论- φ 柜门 )≤5%, the cabinet door shielding effect is judged to be normal and the indication tag position is valid; otherwise, an alarm is triggered to prompt that the shielding is invalid.