Method and system for resisting foreign matter interference during material over-limit detection
By setting detection exclusion zones and adaptively adjusting the light intensity of the through-beam detector, the problem of foreign object interference in material over-limit detection is solved, achieving accurate material over-limit judgment and safe equipment operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-28
- Publication Date
- 2026-04-14
AI Technical Summary
Existing technologies are easily affected by foreign objects in the detection of materials exceeding limits, leading to misjudgments and stacker crane shutdowns, which pose safety hazards.
By setting a detection restricted area, the light intensity at the receiver of the through-beam switch is used to sense the time when the foreign object is located and compared with the detection restricted area. Combined with the Lambert-Beer law, the foreign object penetration threshold and the material over-limit threshold are calculated, so as to realize the adaptive adjustment of the through-beam switch and ensure the accuracy of the judgment.
It effectively avoids the impact of foreign object interference on the detection of material exceeding limits, improves the accuracy of detection and the safety of equipment operation, and reduces manual intervention.
Smart Images
Figure CN121855602A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of material storage technology, and specifically to a method and system for resisting interference from foreign objects when detecting materials exceeding limits. Background Technology
[0002] In the logistics industry, stacker cranes typically use ordinary optical through-beam switches mounted on the loading platform to detect whether goods exceed limits. Traditional ordinary optical through-beam switches, when used for material over-limit detection, only determine whether the received light intensity is below a fixed threshold, without distinguishing between actual material obstruction and foreign object obstruction. In actual industrial applications, the surface of materials on stacker cranes often has labels or packaging films attached. When these objects are not tightly attached, they can float off the surface. Existing technology may misjudge such foreign object obstruction as material over-limit, causing the stacker crane to stop, affecting production operations and efficiency. Furthermore, it requires manual climbing to physically inspect the over-limited items, posing a significant safety hazard. Summary of the Invention
[0003] To address the shortcomings of existing technologies, this invention provides a method and system for resisting foreign object interference during material over-limit detection. It has advantages such as avoiding interference from foreign objects affecting over-limit detection and solves the problem that existing over-limit detection is easily affected by foreign object interference.
[0004] The present invention provides a method and system for resisting foreign object interference during material over-limit detection, comprising the following steps: S10. Install the transmitting end and receiving end of the through-beam light switch to form a detection station; S20. Set a detection restricted area, which is the period during which foreign objects or partial protrusions of the material body pass through the detection station during the time a of material entering and leaving the detection station. S30. Determine the time b at which the light-sensitive receiver receives light intensity to detect the foreign object. S40. Determine whether the material is subject to foreign object interference exceeding the detection limit based on whether the time b obtained in S30 coincides with the detection restricted area time period d.
[0005] In some embodiments, S50: If the light intensity received by the optical switch receiver in S40 is below the threshold and is not caused by foreign object interference, an alarm is issued to suspend the operation of the device.
[0006] In some embodiments, S60: Determine the accuracy of the alarm. If there is foreign object interference (if the alarm is due to the foreign object's characteristic parameters not being recorded, and / or the foreign object interference not being in the detection restricted area), then restart the equipment and record the duration c of the foreign object passing through the detection station, so that the duration c is added to the time b at which it is located, together with the original detection restricted area, to form a new detection restricted area, and cover the original detection restricted area.
[0007] In some embodiments, a beam-on preparation step prior to S10 is also included: S01. Determine the wavelength of the light beam that is transmitted through the beam and establish a database of foreign object characteristic parameters. The foreign object characteristic parameters should include at least the foreign object thickness d, the transmittance of the foreign object to light T, and the absorption coefficient of the foreign object to light μ.
[0008] S02. Based on the Lambert-Beer Law and the relationship between the power P of the through-beam transmitter and the incident light intensity I0, combined with the detection distance L between the through-beam transmitter and the foreign object, the environmental attenuation coefficient K, and the foreign object's characteristic parameters, calculate the foreign object penetration threshold I. min1 and material over-limit threshold I min2 ; S03, based on the detection distance L, foreign object characteristic parameters, and foreign object penetration threshold I... min1 The relationship between the power P of the transmitter when the beam is switched off and the incident light intensity I0 is also established. The transmission power P when the beam is switched off is derived using the Lambert-Beer Law.
[0009] In some embodiments, S31, based on the light intensity I of the through-beam switch receiver... out1 Foreign body penetration threshold I min1 and material over-limit threshold I min2 Compare and determine whether a foreign object or a local protrusion of the material itself is detected; S32. Determine the time b at which the result of a local protrusion of a foreign object or material body occurs.
[0010] S70: If the alarm is triggered because the foreign object characteristic parameters are not recorded in the foreign object characteristic parameter database, new foreign object characteristic parameters will be recorded and the transmission power P of the through-beam switch will be adjusted.
[0011] S02.1 According to the Lambert-Beer Law, the intensity I of light reaching the receiver after penetrating the foreign object is... out1 relational expression By combining the detection distance L between the transmitter and receiver of the through-beam light source, the environmental attenuation coefficient K, and the foreign object characteristic parameters, the foreign object penetration threshold I is calculated. min1 and material over-limit threshold I min2； Foreign object penetration threshold: ; Material exceeding the limit threshold: ; in The transmittance of the material to the light.
[0012] Specifically, the specific transmission power P of the switched-on beam is derived using the Lambert-Beer Law as follows: S03.1, The relationship between the emission power P and the incident light intensity I0 when the beam is switched on and off. Substituting the values into Lambert-Beer's Law, we can express the light intensity I that reaches the receiver after the light penetrates the foreign object. out1 relational expression middle; S03.2, Ensure To reverse-engineer the required transmission power P, ; in: I0: The intensity of the incident light emitted during the through-beam switching, which is positively correlated with the emission power; T: Transmittance of the through-beam light from the foreign object; 1 / L 2 : Light intensity inverse square attenuation, where L is the detection distance between the emitter and receiver of the through-beam light source; K: Environmental degradation coefficient; η: Photoelectric conversion efficiency of the transmitter tube; θ: Half-power angle of the through-beam switching angle; A: The area of the light spot that the incident light hits on the label paper.
[0013] Specifically, S31.1, compare the actual received light intensity I out1 with I min1 I min2 Output the result indicating whether there is a foreign object or material: If I out1 ≥I min1 It was determined to be "no foreign object"; If I min2 ≤I out1 min1 It was determined to be "containing a foreign object"; If I out1 min2 The condition was determined to be "material present".
[0014] A system for preventing foreign object interference during material over-limit detection includes: The storage module is used to input and store the foreign object's characteristic parameters; The threshold calculation module, based on the Lambert-Beer Law and the relationship between the power P of the through-beam transmitter and the incident light intensity I0, and combining the detection distance L between the through-beam transmitter and the foreign object, the environmental attenuation coefficient K, and the foreign object's characteristic parameters, calculates the foreign object penetration threshold I. min1 and material over-limit threshold I min2 ; The adaptive adjustment module adjusts the foreign object based on the detection distance L, foreign object characteristic parameters, and foreign object penetration threshold I. min1 The relationship between the power P of the through-beam switch and the incident light intensity I0 is also established. The transmission power P of the through-beam switch is derived using the Lambert-Beer Law, and the signal is transmitted to the through-beam switch module. The through-beam light switch module includes a light emitting submodule for receiving signals from the adaptive adjustment module and automatically adjusting the power of the through-beam light switch transmitter, and a real-time output of the light intensity I of the through-beam light switch receiver. out1 The light receiving submodule.
[0015] The receiving end of the light-emitting switch has a built-in narrowband filter that matches the output wavelength of the transmitting end, and can output the real-time received light intensity I. out1 ; The determination module, based on the I received in the absolute emission light-emitting module out1 With the threshold calculation module I min1 I min2 Compare and output the judgment result and the time b in which the result occurs; The verification module sets the time period during which foreign objects or partial protrusions of the material body pass through the detection station as the detection restricted area, and verifies the result by checking whether the time b of the judgment module result coincides with the detection restricted area time period d. The alarm module receives information from the verification module and issues an alarm to shut down the equipment if the verification fails.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention can effectively utilize the information obtained by existing through-beam light switches. By comparing the time b when the through-beam light switch receives light intensity below a fixed threshold during a single detection process with the detection restricted area time period d, foreign objects located in the detection restricted area can be effectively ignored, thus avoiding interference caused by foreign objects to the detection of materials exceeding limits.
[0017] 2. This invention ensures the accuracy of alarms. If an alarm is triggered by foreign object interference outside the detection restricted area, the equipment is restarted, and the duration c of the foreign object passing through the detection station is recorded. The duration c is added to the time b of the foreign object, and together with the original detection restricted area, they form a new detection restricted area, covering the original detection restricted area. This effectively updates the detection restricted area. Alternatively, the detection restricted area time period d can be set to 0 to determine the initial detection restricted area time period.
[0018] 3. This invention can effectively control the light intensity I received by the through-beam receiving end. out1 Foreign body penetration threshold I min1 and material over-limit threshold I min2 This allows for a preliminary determination of foreign objects. By comparing the time b of the determination result with the detection restricted area b, the local protrusion of the foreign object or material can be effectively verified to ensure the accuracy of the determination. Attached Figure Description
[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the process of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the process structure of Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the process structure of Embodiment 3 of the present invention; Figure 4 This is a schematic diagram of the specific process structure of steps S30 and S40 in Embodiment 3 of the present invention; Figure 5 This is a schematic diagram of Embodiment 4 of the present invention. Detailed Implementation
[0020] The following drawings will disclose several embodiments of the present invention. For clarity, many physical details will be described in the following description. However, it should be understood that these physical details are not intended to limit the invention. That is, in some embodiments of the invention, these physical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.
[0021] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, such a combination should be considered nonexistent and not within the scope of protection claimed by this invention.
[0022] Example 1: Please see Figure 1 The present invention provides a method for resisting foreign object interference during material over-limit detection, comprising the following steps: S10. Install the transmitting end and receiving end of the through-beam light switch to form a detection station; S20. Set a detection restricted area, which is the period during which foreign objects or parts of the material body protrude through the detection station during the time a of material entering and leaving the detection station. S30. Determine the time b when the light-activated receiver receives light intensity below a fixed threshold and senses a foreign object. S40. Determine whether the material is subject to foreign object interference exceeding the detection limit based on whether the time b obtained in S30 coincides with the detection restricted area time period d; if the time b coincides with the detection restricted area time period d, it is determined to be foreign object interference; if the time b does not completely coincide with the detection restricted area time period d, it is determined to be material exceeding the limit. When this method is adopted, the information obtained by the existing through-beam switch can be effectively utilized. By sensing the time b of the time when the through-beam switch receives light intensity below a fixed threshold during a single detection process, and comparing it with the detection restricted area time period d, foreign objects located in the detection restricted area can be effectively ignored, thus avoiding interference caused by foreign objects to the detection of materials exceeding limits. In this embodiment, it is necessary to ensure that the time 'a' of the material passing through the detection station each time, and the running speed of the material during the time 'a', remain unchanged. In this embodiment, the duration of the restricted area period d is less than the duration a; In this embodiment, when the time b is time point b1, the application range is wide, and it is preferably applied to the working condition where the material body is partially protruding. It can quickly determine whether the detection of non-protruding parts of the material exceeds the limit. In this embodiment, when the current time b is time period b2, it can effectively provide redundancy for the detection restricted area. When the actual time of foreign object entering the detection station fluctuates in the duration of time period b2, and time period b2 does not completely coincide with the detection restricted area time period d, it is determined to be foreign object interference, thus effectively providing redundancy. Among them, time period b2 cannot be greater than the time taken from the beginning and end of the detection restricted area period d to the beginning and end of the material detection surface.
[0023] The preferred method of using time b as time period b2 is used for end face detection of materials that are planar. Since the end face of the material is planar, the duration for which the light-receiving end receives light intensity and senses that the material exceeds the limit is the overall duration a. Since time period b2 is a part of the overall duration a, the over-limit detection can still be achieved when the time b is time period b2.
[0024] Example 2: Please see Figure 2 As a further improvement to Embodiment 1, the method may further include S50: if the light intensity received by the determination light switch receiving end in S40 is below a fixed threshold and is not caused by foreign object interference, then an alarm is issued to suspend the operation of the equipment.
[0025] S60: Determine the accuracy of the alarm. If the alarm is caused by interference from foreign objects in a non-detection restricted area, restart the equipment and record the duration c of the foreign object passing through the detection station. Add the duration c to the time b in which the foreign object is located to form a new detection restricted area together with the original detection restricted area, and cover the original detection restricted area.
[0026] Through the above S50 and S60, a new detection exclusion zone can be effectively established, enabling it to automatically set the detection exclusion zone, ensuring the integrity of the detection exclusion zone, and enhancing the effect of detecting foreign object interference.
[0027] In the above, if the time b is the time period b2, the new detection restricted area formed by S60 is composed of the end time point of b2 plus the duration c and the original detection restricted area, and covers the original detection restricted area.
[0028] This technical solution can effectively update the detection restricted area, and can also set the detection restricted area time period d to 0 to determine the time period of the initial detection restricted area.
[0029] Example 3: Please see Figure 3 and Figure 4 As a further improvement to Embodiment 1, it also includes a beam-opening preparation step located before S10: S01. Determine the wavelength of the light beam that is transmitted through the beam and establish a database of foreign object characteristic parameters. The foreign object characteristic parameters should include at least the foreign object thickness d, the transmittance of the foreign object to light T, and the absorption coefficient of the foreign object to light μ.
[0030] When the foreign object exceeding the limit is ordinary white wood pulp label paper with a thickness of d = 0.2 mm, and the light emitted from the through-beam switch is near-infrared light with a wavelength of 850 nm or 940 nm, T≈0.3~0.6; S02. According to the Lambert-Beer Law, the light intensity I reaching the receiver after passing through the foreign object is... out1 relational expression Based on the detection distance L between the transmitter and receiver of the through-beam light source, the environmental attenuation coefficient K, and the foreign object characteristic parameters obtained in S1, the foreign object penetration threshold I is calculated. min1 and material over-limit threshold I min2 ; Foreign object penetration threshold: ; Material exceeding the limit threshold: ; The transmittance T of the material to near-infrared light material ≤5%, which is estimated based on the actual working conditions and materials. For example, if the material is an industrial material (such as plastic parts, metal parts, granules, etc.), it can hardly penetrate 850nm / 940nm near-infrared light. The actual measured transmittance is generally ≤5%, which is almost completely opaque. Where e is the natural logarithm; S03, based on the detection distance L, foreign object characteristic parameters, and foreign object penetration threshold I... min1The relationship between the power P of the transmitter when the beam is switched off and the incident light intensity I0 is also established. The power P of the transmitter when the beam is switched off is derived using the Lambert-Beer Law. The relationship between the emission power P and the incident light intensity I0 when the beam is switched on and off Substituting the values into Lambert-Beer's Law, we can express the light intensity I that reaches the receiver after the light penetrates the foreign object. out1 relational expression In China; ensure To reverse-engineer the required transmission power P, .
[0031] S10. Install the transmitting end and receiving end of the through-beam light switch to form a detection station; S20. Set a detection restricted area, which is the period during which foreign objects or parts of the material body protrude through the detection station during the time a of material entering and leaving the detection station. S30. Determine the time b at which the light-sensitive receiver receives light intensity to detect the foreign object. S31. Based on the light intensity I at the receiver of the through-beam switch... out1 Foreign body penetration threshold I min1 and material over-limit threshold I min2 Compare and determine whether a foreign object or a local protrusion of the material itself is detected; Comparison I out1 with I min1 I min2 Output the judgment result: If I out1 ≥I min1 It was determined to be "no foreign object"; If I min2 ≤I out1 min1 It was determined to be "containing a foreign object"; If I out1 min2 The condition was determined to be "materials present"; S40. Determine whether the material is subject to foreign object interference exceeding the detection limit based on whether the time b obtained in S30 coincides with the detection restricted area time d. If the time b in S31 where the result is "foreign object present" coincides with the detection restricted area time d, then the verification is considered successful, indicating foreign object interference and that the material does not exceed the limit. If the time b in S31 where the result is "foreign object present" does not completely coincide with the detection restricted area time d, the presence of foreign object is questionable, and it is unclear whether the material exceeds the limit. If the time b in S31 where the result is "material present" coincides with the detection restricted area time d, the material exceeding the limit is questionable, and it is unclear whether the material exceeds the limit; if the detection restricted area setting includes local protrusions of the material body, then the verification is considered successful, and the end face of the material being detected does not exceed the limit. If the time b in S31 where the result is "material present" does not completely coincide with the detection restricted area time d, then the verification is considered successful and the material exceeds the limit. When this method is adopted, the light intensity I received by the through-beam receiver can be effectively controlled. out1 Foreign body penetration threshold I min1 and material over-limit threshold I min2 This allows for a preliminary determination of foreign objects. By comparing the time b of the determination result with the detection restricted area b, the local protrusion of the foreign object or material can be effectively verified to ensure the accuracy of the determination.
[0032] Furthermore, the method may also include S50: if the material is determined to be out of limit in S40, an alarm is issued to suspend the operation of the equipment.
[0033] S60: Determine the accuracy of the alarm. If the alarm is caused by foreign object interference in a non-detection restricted area, restart the equipment and record the duration c of the foreign object passing through the detection station. Add the duration c to the time b in which the foreign object is located to form a new detection restricted area together with the original detection restricted area, and cover the original detection restricted area. S70: If the alarm is triggered because the foreign object characteristic parameters are not recorded in the foreign object characteristic parameter database, new foreign object characteristic parameters will be recorded and the transmission power P of the through-beam switch will be adjusted.
[0034] It facilitates the further collection of information on the location and type of foreign objects. The accuracy of the alarm can be determined manually or by another system.
[0035] Example 4: Please see Figure 5 A system for preventing interference from foreign objects during material over-limit detection, and a method for preventing interference from foreign objects during material over-limit detection according to Embodiment 2, comprising: The storage module is used to input and store the foreign object's characteristic parameters; The threshold calculation module, based on the Lambert-Beer Law and the relationship between the power P of the through-beam transmitter and the incident light intensity I0, and combining the detection distance L between the through-beam transmitter and the foreign object, the environmental attenuation coefficient K, and the foreign object's characteristic parameters, calculates the foreign object penetration threshold I. min1 and material over-limit threshold I min2 ; The adaptive adjustment module adjusts the foreign object based on the detection distance L, foreign object characteristic parameters, and foreign object penetration threshold I. min1 The relationship between the power P of the through-beam switch and the incident light intensity I0 is also established. The transmission power P of the through-beam switch is derived using the Lambert-Beer Law, and the signal is transmitted to the through-beam switch module. The through-beam light switch module includes a light emitting submodule for receiving signals from the adaptive adjustment module and automatically adjusting the power of the through-beam light switch transmitter, and a real-time output of the light intensity I of the through-beam light switch receiver. out1 The light receiving submodule.
[0036] The receiving end of the light-emitting switch has a built-in narrowband filter that matches the output wavelength of the transmitting end, and can output the real-time received light intensity I. out1 ; The determination module, based on the I received in the absolute emission light-emitting module out1 With the threshold calculation module I min1 I min2 Compare and output the judgment result and the time b in which the result occurs; The verification module sets the time period during which foreign objects or partial protrusions of the material body pass through the detection station as the detection restricted area, and verifies the result by checking whether the time b of the judgment module result coincides with the detection restricted area time period d. The alarm module receives information from the verification module and issues an alarm to shut down the equipment if the verification fails.
[0037] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.
Claims
1. A method for resisting interference from foreign objects during material over-limit detection, characterized in that, Includes the following steps: S10. Install the transmitting end and receiving end of the through-beam light switch to form a detection station; S20. Set a detection restricted area, which is the period during which foreign objects or partial protrusions of the material body pass through the detection station during the time a of material entering and leaving the detection station. S30. Determine the time b at which the light-sensitive receiver receives light intensity to detect the foreign object. S40. Determine whether the material is subject to foreign object interference exceeding the detection limit based on whether the time b obtained in S30 coincides with the detection restricted area time period d.
2. The method for resisting foreign object interference during material over-limit detection according to claim 1, characterized in that: S50: If the light intensity received by the optical switch receiver in S40 is below the threshold and is not caused by foreign object interference, an alarm will be issued to suspend the operation of the equipment.
3. The method for resisting foreign object interference during material over-limit detection according to claim 2, characterized in that: S60: Determine the accuracy of the alarm. If there is foreign object interference (if the alarm is due to the foreign object's characteristic parameters not being recorded, and / or the foreign object interference not being in the detection restricted area), restart the equipment and record the duration c of the foreign object passing through the detection station. Add the duration c to the time b in which the foreign object is located, and together with the original detection restricted area, form a new detection restricted area, thus covering the original detection restricted area.
4. The method for resisting foreign object interference during material over-limit detection according to claim 3, characterized in that: It also includes the preparatory steps for the through-beam switch located before S10: S01. Determine the wavelength of the light beam that is transmitted through the beam and establish a database of foreign object characteristic parameters; the foreign object characteristic parameters should include at least the foreign object thickness d, the transmittance of the foreign object to light T, and the absorption coefficient of the foreign object to light μ. S02. Based on the Lambert-Beer Law and the relationship between the power P of the through-beam transmitter and the incident light intensity I0, combined with the detection distance L between the through-beam transmitter and the foreign object, the environmental attenuation coefficient K, and the foreign object's characteristic parameters, calculate the foreign object penetration threshold I. min1 and material over-limit threshold I min2 ; S03, based on the detection distance L, foreign object characteristic parameters, and foreign object penetration threshold I... min1 The relationship between the power P of the transmitter when the beam is switched off and the incident light intensity I0 is also established. The transmission power P of the beam when the beam is switched off is derived using the Lambert-Beer Law.
5. The method for resisting foreign object interference during material over-limit detection according to claim 1, characterized in that: S31. Based on the light intensity I at the receiver of the through-beam switch... out1 Foreign body penetration threshold I min1 and material over-limit threshold I min2 Compare and determine whether a foreign object or a local protrusion of the material itself is detected; S32. Determine the time b at which the result of a local protrusion of a foreign object or material body occurs.
6. The method for resisting foreign object interference during material over-limit detection according to claim 5, characterized in that: S70: If the alarm is triggered because the foreign object characteristic parameters are not recorded in the foreign object characteristic parameter database, new foreign object characteristic parameters will be recorded and the transmission power P of the through-beam switch will be adjusted.
7. The method for resisting foreign object interference during material over-limit detection according to claim 4, characterized in that: S02.1 According to the Lambert-Beer Law, the light intensity I reaching the receiver after passing through a foreign object is... out1 relational expression By combining the detection distance L between the transmitter and receiver of the through-beam light source, the environmental attenuation coefficient K, and the foreign object characteristic parameters, the foreign object penetration threshold I is calculated. min1 and material over-limit threshold I min2； Foreign object penetration threshold: ; Material exceeding the limit threshold: ; in The transmittance of the material to the light.
8. The method for resisting foreign object interference during material over-limit detection according to claim 5, characterized in that: The specific derivation of the transmit power P when the beam is switched off using the Lambert-Beer Law is as follows: S03.1, The relationship between the emission power P and the incident light intensity I0 when the beam is switched on and off. Substituting the values into Lambert-Beer's Law, we can express the light intensity I that reaches the receiver after the light penetrates the foreign object. out1 relational expression middle; S03.2, Ensure To reverse-engineer the required transmission power P, ; in: I0: The intensity of the incident light emitted during the through-beam switching, which is positively correlated with the emission power; T: Transmittance of the through-beam light from the foreign object; 1 / L 2 : Light intensity inverse square attenuation, where L is the detection distance between the emitter and receiver of the through-beam light source; K: Environmental degradation coefficient; η: Photoelectric conversion efficiency of the transmitter tube; θ: Half-power angle of the through-beam switching angle; A: The area of the light spot that the incident light hits on the label paper.
9. The method for resisting foreign object interference during material over-limit detection according to claim 5, characterized in that: S31.1, Compare with the actual received light intensity I out1 With Im in1 I min2 Output the result indicating whether there is a foreign object or material: If I out1 ≥I min1 It was determined to be "no foreign objects"; If I min2 ≤I out1 min1 It was determined to be "a foreign object"; If I out1 min2 The result was determined to be "materials present". 10. A system for preventing foreign object interference during material over-limit detection, characterized in that, The system employs the method for resisting foreign object interference when performing material over-limit detection according to claims 7-9, comprising: The storage module is used to input and store the foreign object's characteristic parameters; The threshold calculation module, based on the Lambert-Beer Law and the relationship between the power P of the through-beam transmitter and the incident light intensity I0, and combining the detection distance L between the through-beam transmitter and the foreign object, the environmental attenuation coefficient K, and the foreign object's characteristic parameters, calculates the foreign object penetration threshold I. min1 and material over-limit threshold I min2 ; The adaptive adjustment module adjusts the foreign object based on the detection distance L, foreign object characteristic parameters, and foreign object penetration threshold I. min1 The relationship between the power P of the through-beam switch and the incident light intensity I0 is also established. The transmission power P of the through-beam switch is derived using the Lambert-Beer Law, and the signal is transmitted to the through-beam switch module. The through-beam light switch module includes a light emitting submodule for receiving signals from the adaptive adjustment module and automatically adjusting the power of the through-beam light switch transmitter, and a real-time output of the light intensity I of the through-beam light switch receiver. out1 The light receiving submodule; The receiving end of the light-emitting switch has a built-in narrowband filter that matches the output wavelength of the transmitting end, and can output the real-time received light intensity I. out1 ; The determination module, based on the I received in the absolute emission light-emitting module out1 With the threshold calculation module I min1 I min2 Compare and output the judgment result and the time b in which the result occurs; The verification module sets the time period during which foreign objects or partial protrusions of the material body pass through the detection station as the detection restricted area, and verifies the result by checking whether the time b of the judgment module result coincides with the detection restricted area time period d. The alarm module receives information from the verification module and issues an alarm to shut down the equipment if the verification fails.