Radio elevator light curtain anti-interference method and radio elevator light curtain device

Abstract

A method and device for preventing interference with wireless elevator light curtains are disclosed, relating to the field of wireless elevator light curtain technology, to improve the quality of the radio frequency communication link of the wireless elevator light curtain device. In this method, the wireless elevator light curtain device establishes an alternating working mechanism of charging and communication time windows, physically isolating the high-power, high-frequency alternating magnetic field generated by wireless charging from the low-power radio frequency communication conducted by the light curtain device, thereby avoiding electromagnetic interference problems caused by both operating simultaneously.

Description

Technical Field

[0001] This application relates to the field of wireless elevator light curtain technology, and in particular to a wireless elevator light curtain anti-interference method and a wireless elevator light curtain device. Background Technology

[0002] An elevator light curtain is a safety protection device installed on the edge of an elevator car door. It forms a protective surface by emitting and receiving infrared beams to detect whether there are passengers or obstacles in the door area while the elevator door is moving or remaining open, thereby preventing accidents of people being trapped.

[0003] In wirelessly powered elevator light curtain technology, to maintain the long-term battery life of the light curtain device's built-in battery, the relevant technology typically employs a combination of wireless electromagnetic induction charging and door status linkage control to solve the long-term power supply problem. Specifically, wireless charging transmitting and receiving coils are placed at corresponding positions in the elevator car and on the light curtain device. The door control system monitors the elevator door's operating status in real time. When the elevator door reaches its fully open or fully closed limit position and remains stationary, the control circuit activates the charging output, driving the wireless charging transmitter to generate a high-frequency alternating magnetic field. The receiving coil on the light curtain obtains electrical energy through electromagnetic induction, charging the battery. During charging, the radio frequency communication module and infrared detection module inside the light curtain remain battery-powered, continuously operating and sending infrared light curtain status signals and system heartbeat messages to the door control mainboard at a fixed frequency, ensuring uninterrupted safety protection functions.

[0004] However, when the elevator doors are open and in the passenger-waiting position, the light curtain is in a high-frequency scanning and high-level security alert phase. If the wireless charging transmitter is activated at this time, its high-power, high-frequency alternating magnetic field and the light curtain's own weak wireless radio frequency communication signal will coexist in the narrow near-field space of the elevator door. This high-power alternating magnetic field may generate strong EMI electromagnetic interference, penetrating and suppressing the radio frequency communication link. Summary of the Invention

[0005] This application provides a method for anti-interference of wireless elevator light curtain and a wireless elevator light curtain device, which are used to improve the quality of the radio frequency communication link of the wireless elevator light curtain device.

[0006] A first aspect provides a method for anti-interference of a wireless elevator light curtain, characterized in that it is applied to a wireless elevator light curtain device, the wireless elevator light curtain device including a power supply device and a light curtain device, the power supply device including a transmitting coil, the light curtain device including a receiving coil, a radio frequency communication module and an impedance adjustment circuit connected to the receiving coil, the radio frequency communication module being communicatively connected to the door operator controller, the method comprising: the power supply device, based on the elevator door opening signal, alternately dividing a charging time window and a communication time window according to a preset cycle; within the charging time window, the power supply device wirelessly charges by outputting a high-frequency alternating magnetic field through the transmitting coil, while the light curtain device keeps the radio frequency communication module in a sleep state, performs infrared beam scanning, and stores the infrared light status data obtained by scanning in a local cache; when switching from the charging time window to the communication time window, the power supply device stops outputting the high-frequency alternating magnetic field; after the light curtain device wakes up the radio frequency communication module, the radio frequency communication module sends the infrared light status data in the local cache to the door operator controller.

[0007] By adopting the above technical solution, the wireless elevator light curtain device establishes an alternating working mechanism of charging time window and communication time window, which physically isolates the high-power high-frequency alternating magnetic field generated by wireless charging from the low-power radio frequency communication of the light curtain device, thereby avoiding the electromagnetic interference problem caused by the simultaneous operation of the two.

[0008] In conjunction with some embodiments of the first aspect, in some embodiments, after the light curtain device wakes up the radio frequency communication module and the radio frequency communication module sends the infrared light status data in the local cache to the door controller, the method further includes: during the charging time window, if the light curtain device determines that there is an obstacle obstructing the circuit based on the infrared light status data, the light curtain device controls the impedance adjustment circuit to change the load impedance at the receiving coil end; the power supply device monitors the output current of the transmitting coil in real time, and when it detects a change in the output current caused by the change in load impedance, the power supply device determines that an emergency obstruction event has occurred, and terminates the current charging time window in advance, stopping the output of the high-frequency alternating magnetic field; after the light curtain device detects that the induced electrical signal corresponding to the receiving coil has disappeared, it wakes up the radio frequency communication module and sends safety alarm data representing the obstacle obstruction to the door controller.

[0009] By adopting the above technical solution, an in-band communication mechanism that uses changes in load impedance to transmit emergency blocking signals during the charging window ensures that there is almost no delay in safety response even when the radio frequency module is in sleep mode, thereby improving the safety of elevator operation while ensuring the long-term battery life of the wireless light curtain.

[0010] In conjunction with some embodiments of the first aspect, in some embodiments, the step of the light curtain device control impedance adjustment circuit changing the load impedance at the receiving coil end specifically includes: the light curtain device control impedance adjustment circuit alternately turns on and off the bypass resistor connected across the two ends of the receiving coil according to a preset characteristic pulse code, so that the working impedance of the receiving coil switches frequently between the matched state and the mismatched state, thereby obtaining a reverse induced potential sequence corresponding to the characteristic pulse code.

[0011] By adopting the above technical solution, the wireless elevator light curtain device upgrades the interference-prone impedance step signal into a sequence of impedance changes carrying a preset characteristic pulse code. This is equivalent to establishing a low-speed digital communication link based on load modulation at the physical layer, so that the emergency signal contains a specific code pattern. This encoding mechanism allows the power supply equipment to identify the signal through pattern matching, thereby enhancing the anti-interference capability.

[0012] In conjunction with some embodiments of the first aspect, in some embodiments, the power supply equipment monitors the output current of the transmitting coil in real time. When a change in the output current caused by a change in load impedance is detected, the power supply equipment determines that an emergency blocking event has occurred. Specifically, the power supply equipment continuously collects the primary AC current of the transmitting coil and extracts the amplitude envelope of the primary AC current; the power supply equipment parses the current drop edge array according to the fluctuation pattern of the amplitude envelope, and determines that an emergency blocking event has occurred when it is determined that the time interval distribution of the current drop edge array is consistent with the bit width protocol of the characteristic pulse code.

[0013] By adopting the above technical solution, the power supply equipment extracts the current amplitude envelope and decodes the time interval distribution of the drop-off along the array on the envelope to strictly match it with the characteristic pulse code sent by the light curtain equipment. Only signal patterns that conform to the preset bit width protocol will be confirmed as emergency events, thereby reducing the false judgment rate of emergency events and improving reliability.

[0014] In conjunction with some embodiments of the first aspect, in some embodiments, the step of resolving the current drop-edge array based on the fluctuation pattern of the amplitude envelope by the power supply device specifically includes: the power supply device calculating the current difference value of the amplitude envelope within two adjacent sampling periods; when the absolute value of the current difference value exceeds a preset noise floor threshold and the continuous decreasing duration of the amplitude envelope conforms to a preset falling edge characteristic, the current sampling time is marked as a valid edge trigger point; the power supply device collects all valid edge trigger points within a preset judgment window period to obtain the current drop-edge array.

[0015] By adopting the above technical solution, the rapid changes in current can be captured more sensitively by calculating the current difference value and comparing it with the noise floor threshold. At the same time, by judging whether the continuous decreasing duration conforms to the falling edge characteristics, noise spikes that are large in amplitude but do not conform to the shape can be effectively filtered out, making the extraction of the effective edge trigger point more accurate and reliable, and further improving the accuracy of decoding.

[0016] In conjunction with some embodiments of the first aspect, in some embodiments, the step of switching from the charging time window to the communication time window specifically includes: within the charging time window, the light curtain device does not rely on a local clock to drive the switching of the communication time window, but instead monitors the amplitude of the induced voltage across the receiving coil in real time; only when the light curtain device detects that the amplitude of the induced voltage has fallen below the minimum safe voltage threshold for maintaining the normal operation of the impedance adjustment circuit, a hard synchronization interrupt signal is generated; the light curtain device clears its local delay counter according to the hard synchronization interrupt signal, and uses the moment when the hard synchronization interrupt signal is triggered as the starting point for entering the communication time window.

[0017] By adopting the above technical solution, the light curtain device no longer relies on a local clock that may drift. Instead, it initiates communication based on the unambiguous physical event of the disappearance of the induced voltage. This ensures that its radio frequency module is always awakened only after the charging magnetic field has completely disappeared, avoiding the risk of the communication chip being damaged by a strong magnetic field, thereby enhancing safety.

[0018] In conjunction with some embodiments of the first aspect, in some embodiments, within the communication time window, the method further includes: when the radio frequency communication module sends infrared light status data in its local buffer, it appends a communication end frame indicating that the buffer has been emptied to the end of the data stream; the power supply device enables the radio frequency listening channel to intercept the communication response packet returned by the door controller to the radio frequency communication module during the communication time window; when the communication response packet is successfully intercepted, the power supply device terminates the communication time window early to release the remaining time allowance; the power supply device compensates the time allowance for the charging time window of the next cycle and re-outputs the high-frequency alternating magnetic field.

[0019] By adopting the above technical solution, the time resources saved after the communication task is completed ahead of schedule are dynamically reallocated to the charging task, thereby improving the charging efficiency of the light curtain device and extending its battery life.

[0020] In a second aspect, embodiments of this application provide a wireless elevator light curtain device, which includes: one or more processors and a memory; the memory is coupled to the one or more processors, and the memory is used to store computer program code, which includes computer instructions, and the one or more processors call the computer instructions to cause the wireless elevator light curtain device to perform the method described in the first aspect and any possible implementation thereof.

[0021] Thirdly, embodiments of this application provide a computer program product containing instructions that, when the computer program product is run on a wireless elevator light curtain device, cause the wireless elevator light curtain device to perform the method described in the first aspect and any possible implementation thereof.

[0022] Fourthly, embodiments of this application provide a computer-readable storage medium including instructions that, when executed on a wireless elevator light curtain device, cause the wireless elevator light curtain device to perform the method described in the first aspect and any possible implementation thereof.

[0023] Understandably, the wireless elevator light curtain device provided in the second aspect, the computer program product provided in the third aspect, and the computer storage medium provided in the fourth aspect are all used to execute the methods provided in the embodiments of this application. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods, and will not be repeated here.

[0024] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0025] 1. The wireless elevator light curtain device establishes an alternating working mechanism of charging time window and communication time window, which physically isolates the high-power high-frequency alternating magnetic field generated by wireless charging from the low-power radio frequency communication of the light curtain device, thereby avoiding the electromagnetic interference problem caused by the simultaneous operation of the two.

[0026] 2. The in-band communication mechanism that uses changes in load impedance to transmit emergency blocking signals during the charging window ensures that there is almost no delay in safety response even when the RF module is in sleep mode, thereby improving the safety of elevator operation while ensuring the long battery life of the wireless light curtain.

[0027] 3. The wireless elevator light curtain device upgrades the interference-prone impedance step signal into a sequence of impedance changes carrying a preset characteristic pulse code. This is equivalent to establishing a low-speed digital communication link based on load modulation at the physical layer, so that the emergency signal contains a specific code pattern. This encoding mechanism allows the power supply equipment to identify the signal through pattern matching, thereby enhancing the anti-interference capability. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating a wireless elevator light curtain anti-interference method in an embodiment of this application.

[0029] Figure 2 This is another flowchart illustrating a wireless elevator light curtain anti-interference method in an embodiment of this application.

[0030] Figure 3This is a schematic diagram of the physical structure of a wireless elevator light curtain device in the embodiments of this application. Detailed Implementation

[0031] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to and includes any or all possible combinations of one or more of the listed items.

[0032] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0033] This application provides a wireless elevator light curtain anti-interference method and a wireless elevator light curtain device to improve elevator safety.

[0034] This application provides a wireless elevator light curtain device, which consists of two parts: first, a power supply device installed on the side of the elevator car, which contains at least one transmitting coil for generating a magnetic field; second, a light curtain device installed on the elevator door, which contains at least one receiving coil coupled to the transmitting coil to receive energy, an RF communication module for wireless data transmission, and an impedance adjustment circuit connected to the receiving coil. The RF communication module maintains a communication connection with the door operator controller.

[0035] Please see Figure 1 This is a flowchart illustrating a wireless elevator light curtain anti-interference method in an embodiment of this application.

[0036] S101. The power supply equipment, based on the elevator door opening signal, alternately divides the charging time window and the communication time window according to a preset cycle.

[0037] The power supply equipment refers to the device installed on the elevator car side, responsible for providing energy to the light curtain equipment. The elevator door opening signal is a digital or analog signal issued by the elevator main control system or door operator controller, indicating that the elevator door has moved to the fully open position and remains stationary. The preset cycle refers to the duration of a complete work cycle, which includes one charging process and one communication process. The charging time window represents the time period specifically allocated for wireless charging within the preset cycle. The communication time window represents the time period specifically allocated for radio frequency communication within the preset cycle.

[0038] Specifically, when the elevator is running and stops at a floor, and the elevator doors are fully open for passengers to enter and exit, the door controller generates and sends a stable and valid elevator door-opening signal. After continuously monitoring this signal, the microcontroller inside the power supply equipment switches from standby or normal operation to time-division multiplexing mode. In this state, the power supply equipment no longer continuously outputs a charging magnetic field, but instead starts an internal periodic timer. This timer cycles according to a preset time length (i.e., a pre-defined period). Within one period, the timer divides the time into two non-overlapping parts: the first part is defined as the charging time window, and the second part as the communication time window. These two parts alternate, thus creating time isolation at the physical level for subsequent wireless charging and radio frequency communication, avoiding electromagnetic interference that may occur when both operate concurrently.

[0039] In some embodiments, the periodic division in this step can be implemented in several ways: Optionally, the microcontroller of the power supply device has two cascaded hardware timers / counters built in. After receiving the elevator door opening signal, the first timer is started to count the charging time window. When the first timer overflows, an interrupt is generated. In the interrupt service routine, the charging action is stopped and the second timer is immediately started to count the communication time window. When the second timer overflows, another interrupt is generated, the communication-related actions are stopped, and the first timer is restarted. This cycle repeats to achieve precise alternation of the time windows. Optionally, the microcontroller of the power supply device adopts a task scheduling scheme based on the operating system. Two high-priority periodic tasks are preset, namely the charging task and the communication task, and different start delays and execution cycles are set for them. The elevator door opening signal serves as a trigger condition to activate the scheduling of these two tasks. The operating system kernel ensures that only one task is running at any given time according to the preset time slice scheduling strategy, thereby realizing the division of the charging time window and the communication time window.

[0040] S102. During the charging window, the power supply device outputs a high-frequency alternating magnetic field through the transmitting coil for wireless charging. At the same time, the light curtain device keeps the radio frequency communication module in a dormant state, performs infrared beam scanning, and stores the infrared light status data obtained from the scan into the local cache.

[0041] In this context, the radio frequency (RF) communication module being in sleep mode indicates that the module's RF transceiver link, modem, and even part of the core processor are in low-power or power-off mode, not transmitting or receiving any radio waves. Infrared beam scanning refers to the infrared emitting and receiving arrays on the light curtain device scanning pair by pair in a specific order and frequency to determine whether there are obstacles within the light curtain's protected area. Infrared light status data is used to represent the result of each infrared beam scan, such as recording a binary sequence indicating whether each pair of beams is conducting or blocked.

[0042] Specifically, upon entering the charging window defined in step S101, the power supply device's drive circuit begins operation, driving the transmitting coil to generate a high-energy, high-frequency alternating magnetic field. Energy is coupled to the light curtain device's receiving coil via this magnetic field, and after rectification and filtering, charges the light curtain device's built-in battery. During the charging window, to reduce interference, the light curtain device's controller puts the radio frequency communication module into a deep sleep mode. However, since the elevator door is open, the safety protection function cannot be interrupted; therefore, the light curtain device's infrared scanning function remains active, continuously performing high-frequency detection on the door area. Its microcontroller packages the raw infrared light state data obtained from each full-array scan, reflecting whether the current door area is obstructed, into a data frame and temporarily stores it in a local buffer. This method of detection followed by buffering ensures that safety status information is not lost during the charging window when wireless communication is not possible.

[0043] Furthermore, to address the transient interference that the high-frequency alternating magnetic field itself might cause to the precise analog-to-digital sampling process of infrared scanning within the charging window, the steps for performing infrared beam scanning can be optimized in this embodiment. Specifically, the light curtain device can use a phase-locked loop circuit to more accurately extract the phase signal from the high-frequency AC voltage induced on the receiving coil and more precisely locate the zero-crossing point of this phase signal each time it crosses zero. Since the high-frequency alternating magnetic field generates the strongest electromagnetic switching transient noise when it flips between peaks and troughs, and the area near the zero-crossing point is a relatively quiet region, this zero-crossing point can be used as a high-precision hardware trigger source to control the emission timing of the drive pulse of the infrared emitting tube on the light curtain device and the analog-to-digital sampling timing of the infrared receiving tube, ensuring that both are strictly aligned within the quiet region of the preset time width where the zero-crossing point is located. In this way, the key action of infrared scanning actively avoids the strongest magnetic field interference, thereby improving the detection accuracy and reliability of infrared light state data without affecting charging.

[0044] S103. When switching from the charging time window to the communication time window, the power supply equipment stops outputting the high-frequency alternating magnetic field.

[0045] Switching to the communication window indicates that the time period allocated for charging within the current preset cycle has ended, and a time period specifically for communication is about to begin. Stopping the output of the high-frequency alternating magnetic field means that the power supply equipment actively disconnects or suppresses the operation of its internal power amplifier circuit, causing the transmitting coil to no longer radiate electromagnetic energy.

[0046] Specifically, when the timing logic inside the power supply equipment determines that the current charging window has reached its set end time, its main controller immediately issues a control command. This command acts on the power drive stage that drives the transmitting coil, such as an H-bridge or half-bridge circuit. The control command causes the power switching transistors (such as MOSFETs) in the drive circuit to stop high-frequency switching, thereby stopping the high-frequency, high-current flowing through the transmitting coil, and the high-frequency alternating magnetic field also disappears rapidly. The core purpose of this action is to purify the electromagnetic environment in advance before the start of radio frequency communication, providing a lower interference transmission channel for the subsequent weak radio frequency signals, thereby improving the reliability and data integrity of communication.

[0047] In some embodiments, the power supply and light curtain devices are two independent wireless units, and their internal clocks may drift. If the switching of time windows relies solely on their respective timers, the light curtain device may wake up the radio frequency module prematurely while the power supply device has not yet stopped the magnetic field, causing damage to the communication link. To solve this synchronization problem, the step of switching from the charging time window to the communication time window can be improved. Specifically, this step can be implemented as follows: On the light curtain device side, its controller, within the charging time window, does not rely on its local clock to drive the switching to the communication time window, but instead monitors the induced voltage amplitude across the receiving coil in real time. After the power supply device reaches the end of the charging time window according to its local clock and stops outputting the magnetic field, the induced voltage amplitude on the light curtain device side will drop rapidly. Only when the light curtain device detects that the induced voltage amplitude has dropped below a preset minimum safe voltage threshold that maintains the normal operation of basic functions such as the impedance adjustment circuit, does it confirm that the magnetic field has completely disappeared and generate a hard synchronization interrupt signal. The interrupt signal has the highest priority. Its trigger time is used by the light curtain device as the absolute starting point for entering the communication time window. It can also be used to clear the local related delay counter before safely executing the wake-up RF module action in step S104.

[0048] S104. After the light curtain device wakes up the radio frequency communication module, the radio frequency communication module sends the infrared light status data in the local cache to the door controller.

[0049] "Wake-up of the RF communication module" refers to restoring it from a low-power sleep state to a fully functional operating state through control signals. "Sending to the door operator controller" means that the RF communication module encodes and modulates the data, then transmits it in the form of radio waves, which are received and demodulated by the wireless receiving device on the door operator controller side.

[0050] Specifically, after the power supply stops outputting the magnetic field, the controller of the light curtain device first sends a wake-up signal to the RF communication module, which is in a dormant state (e.g., via a dedicated interrupt pin or I2C / SPI command). Upon receiving the wake-up signal, the RF communication module undergoes a brief initialization process, including reloading the configuration, stabilizing the phase-locked loop, and starting the RF front-end. Once the module is ready, the controller retrieves a series of infrared light status data stored during the charging window from its local cache, following a first-in, first-out principle. This data is then delivered to the RF communication module, which performs protocol encapsulation (e.g., adding frame headers, checksums, etc.) and finally transmits it to the door operator controller waiting on the elevator car top or door operator.

[0051] In some embodiments, to avoid wasting communication window time when the amount of communication data is small, an adaptive time window termination adjustment mechanism can be introduced within the communication window. Specifically, when the RF communication module sends infrared light status data from its local buffer, a special communication end frame is appended to the very end of all data streams to clearly indicate that all data has been sent. Simultaneously, the power supply device does not completely go into sleep mode after entering the communication window; instead, it activates a low-power RF listening channel. This channel is specifically used to intercept communication response packets returned by the door controller to the light curtain device's RF communication module. Once the power supply device successfully intercepts the response packet, it means that the communication has been successfully completed. At this point, the power supply device will no longer wait for the communication window to complete its preset duration but will immediately terminate it early, dynamically compensating for the remaining time in the next charging window cycle, and immediately re-outputting the high-frequency alternating magnetic field to begin charging.

[0052] In the above embodiments, the wireless elevator light curtain device establishes an alternating working mechanism of charging time window and communication time window, which physically isolates the high-power high-frequency alternating magnetic field generated by wireless charging from the low-power radio frequency communication of the light curtain device, thereby avoiding the electromagnetic interference problem caused by the simultaneous operation of the two.

[0053] However, while the light curtain device can perform infrared scanning normally during the charging window, if an emergency obstruction event occurs, the resulting safety alarm data can only be stored in the local cache and must wait for the next communication window before it can be sent. This inherent delay may not meet safety response requirements in certain high-speed door closing or emergency situations. To address this safety hazard of not being able to report emergency events in a timely manner during charging, this application also provides the following further embodiments.

[0054] Please see Figure 2 This is another flowchart illustrating a wireless elevator light curtain anti-interference method in an embodiment of this application.

[0055] S201. The power supply equipment, based on the elevator door opening signal, alternately divides the charging time window and the communication time window according to a preset cycle.

[0056] S202. During the charging window, the power supply device outputs a high-frequency alternating magnetic field through the transmitting coil for wireless charging. At the same time, the light curtain device keeps the radio frequency communication module in a dormant state, performs infrared beam scanning, and stores the infrared light status data obtained from the scan into the local cache.

[0057] S203. When switching from the charging time window to the communication time window, the power supply equipment stops outputting the high-frequency alternating magnetic field.

[0058] S204. After the light curtain device wakes up the radio frequency communication module, the radio frequency communication module sends the infrared light status data in the local cache to the door controller.

[0059] Step S201 is similar to step S101, step S202 is similar to step S102, step S203 is similar to step S103, and step S204 is similar to step S104, so they will not be repeated here.

[0060] S205. During the charging window, if the light curtain device determines that there is an obstacle blocking it based on the infrared light status data, the light curtain device controls the impedance adjustment circuit to change the load impedance at the receiving coil end.

[0061] Impedance adjustment circuit refers to a circuit attached to the rear end of the receiving coil that can dynamically change its equivalent load through an electronic switch. Changing the load impedance at the receiving coil end means that through this circuit, the electrical load of the receiving coil during energy conversion changes significantly, for example, from an optimal matched impedance to a mismatched short-circuit or open-circuit state.

[0062] Specifically, considering that if the light curtain device detects a passenger or object obstructing the infrared beam during the charging window, this crucial safety information cannot be immediately reported via conventional radio frequency communication. To address this delay, this solution utilizes the wireless charging system itself. When the light curtain device's controller analyzes the infrared light status data and determines obstruction, it no longer waits for the communication window to open but immediately activates its internal impedance regulation circuit. This circuit's operation disrupts the original load state of the receiving coil, optimized for efficient charging. This drastic load change, based on the mutual inductance principle of electromagnetic induction, reacts on the transmitting end, causing corresponding changes in the electrical parameters of the transmitting coil. This indirectly transmits the obstruction event information to the power supply equipment through the physical layer channel itself.

[0063] In some embodiments, the impedance change in this step can be achieved in several ways: Optionally, the impedance adjustment circuit includes a power MOSFET connected in parallel with the rectifier bridge input of the receiving coil. During normal charging, this MOSFET is off and does not affect the circuit. When an obstruction is detected, the controller drives the MOSFET to conduct in the saturation region via a drive signal, which is equivalent to applying a very low impedance load across the receiving coil, approximating a short circuit, thereby significantly changing the load impedance. Optionally, the impedance adjustment circuit includes a relay or solid-state switch connected in series between the receiving coil and the rectifier bridge. During normal charging, the switch is closed. When an obstruction is detected, the controller controls the switch to open, causing the load on the receiving coil to momentarily become unloaded, and the load impedance to become infinite.

[0064] In some embodiments, the start of the elevator main motor, the switching of the car lighting system, or the proximity of a metal object carried by a passenger may cause similar single-current fluctuations in the transmitting coil. This can lead the power supply equipment to misinterpret these unrelated disturbances as genuine emergency obstruction events, resulting in unnecessary charging interruptions and false alarms. To address this issue, when the light curtain device detects an obstruction within the charging window, it no longer simply places the load in a fixed mismatch state. Instead, it initiates an encoding modulation process. Its controller reads a preset characteristic pulse code from memory and then, based on the 0s and 1s of this code, controls the bypass resistor in the impedance adjustment circuit to alternately turn on and off at a higher frequency (far higher than the time window switching frequency, but still within the sampling capability range of the power supply equipment). For example, a 1 in the code corresponds to turning on the bypass resistor for 10 microseconds (causing mismatch), and a 0 corresponds to turning off the bypass resistor for 10 microseconds (restoring matching). In this way, during an emergency, a sequence of reverse induced potentials carrying digital information was transmitted outward through load modulation. This is equivalent to achieving low-speed in-band communication under a strong magnetic field background, which improves information carrying capacity and resistance to accidental interference.

[0065] S206. The power supply equipment monitors the output current of the transmitting coil in real time. When it detects a change in the output current caused by a change in the load impedance, the power supply equipment determines that an emergency blocking event has occurred and terminates the current charging window in advance, stopping the output of the high-frequency alternating magnetic field.

[0066] Real-time monitoring of the output current of the transmitting coil refers to the continuous acquisition of the current value flowing through the transmitting coil by the power supply equipment through a current sensor (such as a sampling resistor or a Hall sensor). Output current variation refers to abnormal jumps in the acquired current value that exceed the normal charging fluctuation range and have specific characteristics, such as a sharp increase or decrease in current.

[0067] Specifically, throughout the entire charging window, the power supply equipment does more than just output power. Its internal controller closely monitors the output current of the transmitting coil through high-frequency sampling. During stable charging, this current remains at a relatively stable level. However, if the load impedance of the light curtain device changes as in step S105, this change is reflected in the reflected impedance of the transmitting coil through magnetic field coupling, directly causing a drastic and identifiable abrupt change in its output current (e.g., a secondary short circuit causes a spike in primary current). Once the power supply equipment's controller detects this predefined current anomaly, it interprets it as an emergency blocking event on the light curtain side. At this point, it immediately abandons the original time window division and executes the highest priority operation: immediately terminating the current charging window and stopping the output of the high-frequency alternating magnetic field.

[0068] In some embodiments, directly analyzing the original AC current waveform is difficult in order to more accurately identify subtle changes caused by load modulation of the light curtain device from a high-frequency, high-current background. Therefore, the signal processing unit of the power supply equipment can first perform envelope detection on the primary AC current acquired by the current sensor. This process can be implemented by hardware circuits (such as a simple envelope detector composed of diodes, resistors, and capacitors) or software algorithms (such as taking the modulus after performing a Hilbert transform on the sampled signal). The core objective is to strip away the carrier information at tens of thousands of hertz or higher frequencies and extract the amplitude envelope, which reflects the load changes at a much lower frequency. This envelope becomes a relatively clean data stream, and subsequent decoding algorithms will be performed on this curve, rather than on the original, noisy AC signal. Furthermore, the amplitude envelope extraction in this step can be achieved in several ways: optionally, the power supply equipment uses a digital peak detection algorithm. Within the high-speed ADC sampling period of its microcontroller, several original current sample points are continuously acquired, and then the maximum value among these sample points is found through software comparison, and this maximum value is used as the envelope amplitude at the current moment. This method is simple to implement and consumes minimal processor resources. Optionally, the power supply can employ digital lock-in amplifier technology. By digitally mixing and low-pass filtering the acquired current signal with a reference quadrature signal that is in phase and frequency with the drive signal, the in-phase and quadrature components of the signal can be extracted more accurately, allowing for the calculation of the amplitude. This method offers a higher signal-to-noise ratio and better anti-interference capability.

[0069] In some embodiments, the controller of the power supply equipment performs pattern recognition on the amplitude envelope after obtaining it. It searches for drops or dips on the envelope that conform to a specific pattern (corresponding to the moment when the bypass resistor of the light curtain device causes load mismatch). For each valid drop identified, its timestamp is recorded, thus forming a current drop edge array. Subsequently, the time interval between adjacent timestamps in this array is calculated. Finally, this actually measured time interval sequence is compared with a standard time interval sequence pre-stored locally, defined by a bit-width protocol encoded by characteristic pulses. Only when the two match within the allowable error range—for example, detecting a long-short-short-long time interval sequence that matches the bit-width protocol encoded 1001—is it finally confirmed as a genuine emergency blocking signal actively emitted by the light curtain device, and the charging and magnetic field stopping operations are immediately executed. This code-matching-based judgment mechanism can eliminate irregular single current jumps caused by external electromagnetic interference or power fluctuations, avoiding false alarms in the system.

[0070] In some embodiments, to more accurately deduce the current drop-edge array based on the fluctuation pattern of the amplitude envelope, an algorithm based on differential and threshold judgment can be employed. Specifically, the microcontroller of the power supply device can: First, calculate the current difference value of the amplitude envelope obtained by S206 within two adjacent sampling periods. Then, when the absolute value of the current difference value exceeds a preset noise floor threshold used to filter out normal noise, and the amplitude envelope shows a continuously decreasing trend with its duration conforming to the expected falling edge characteristics, the current sampling point is marked as a valid edge trigger point. Next, within a preset judgment window period, all marked valid edge trigger points are collected to form a high-confidence current drop-edge array for subsequent comparison with the bit-width protocol.

[0071] S207. After the light curtain device detects the disappearance of the induced electrical signal corresponding to the receiving coil, it wakes up the radio frequency communication module and sends safety alarm data indicating that the obstacle is blocking the door controller.

[0072] The disappearance of the induced electrical signal refers to the situation where the power supply equipment stops outputting the magnetic field, resulting in the receiving coil no longer being able to sense effective voltage and current. Safety alarm data refers to a special data packet indicating that an obstacle obstruction event has occurred, requiring the door controller to immediately execute a safety response action (such as stopping the door from closing or reversing the door opening).

[0073] Specifically, after the power supply responds to the emergency signal and stops outputting the magnetic field, the light curtain device immediately senses this change—the induced voltage on its receiving coil rapidly drops to zero. The controller of the light curtain device uses this disappearance of the induced electrical signal as confirmation that the power supply has received the emergency signal. Once the electromagnetic environment is confirmed to be safe, the controller immediately wakes up the radio frequency communication module and instructs it to send a high-priority safety alarm data packet. This data packet can be the infrared light status data detected when the impedance change was triggered, or a specially coded alarm command. In this way, emergency blocking information, which originally required a communication window to be sent, can be reliably transmitted in a very short time after the event occurs through a clever physical layer handshake time window switching, thus improving the safety response speed.

[0074] In the above embodiments, a mechanism is further introduced to instantly transmit emergency blocking events using load impedance changes within the charging time window. This mechanism achieves preemptive interruption of the preset time window through a physical layer handshake, ensuring that emergency safety alarms can be transmitted with near-zero latency. Furthermore, a load modulation signaling mechanism based on characteristic pulse coding, along with matching envelope extraction and pattern recognition decoding methods, is introduced. This elevates physical layer emergency communication from analog signal transmission to a more reliable digital information exchange, giving emergency signaling stronger anti-interference characteristics and recognizability. It can resist various electromagnetic noises in the elevator environment, thereby reducing misjudgments and further improving the overall safety and reliability of the elevator.

[0075] The above describes a method for preventing interference with a wireless elevator light curtain in the embodiments of this application. The following describes an exemplary wireless elevator light curtain device 300 provided in the embodiments of this application.

[0076] Figure 3This is an exemplary hardware structure diagram of the wireless elevator light curtain device 300 provided in this application embodiment. In some embodiments, the wireless elevator light curtain device 300 is a computer device. The computer device includes a processor, a memory, and a network interface connected via a system bus. The processor of the computer device provides computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database of the computer device is used to store data. The network interface of the computer device is used to communicate with other external terminals or servers via a network connection. In some embodiments, the network interface can be a wired network interface; in some embodiments, the network interface can also be a wireless network interface. When the computer program is executed by the processor, it implements a wireless elevator light curtain anti-interference method according to an embodiment of this application.

[0077] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0078] In some embodiments of this application, a computer-readable storage medium is also provided, including instructions that, when executed on the wireless elevator light curtain device 300, cause the wireless elevator light curtain device 300 to perform a wireless elevator light curtain anti-interference method according to an embodiment of this application.

[0079] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0080] As used in the above embodiments, depending on the context, the term "when..." can be interpreted as meaning "if...", "after...", "in response to determining...", or "in response to detecting...". Similarly, depending on the context, the phrase "when determining..." or "if (the stated condition or event) is interpreted as meaning "if determining...", "in response to determining...", "when (the stated condition or event) is detected", or "in response to detecting (the stated condition or event)".

[0081] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0082] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A method for preventing interference with a wireless elevator light curtain, characterized in that, An application is made to a wireless elevator light curtain device, the wireless elevator light curtain device including a power supply device and a light curtain device, the power supply device including a transmitting coil, the light curtain device including a receiving coil, a radio frequency communication module, and an impedance adjustment circuit connected to the receiving coil, the radio frequency communication module being communicatively connected to a door operator controller, the method including: The power supply equipment, based on the elevator door opening signal, alternately divides the charging time window and the communication time window according to a preset cycle; During the charging window, the power supply device wirelessly charges by outputting a high-frequency alternating magnetic field through the transmitting coil. At the same time, the light curtain device keeps the radio frequency communication module in a sleep state, performs infrared beam scanning, and stores the infrared light status data obtained from the scan into a local cache. When switching from the charging time window to the communication time window, the power supply device stops outputting the high-frequency alternating magnetic field; After the light curtain device wakes up the radio frequency communication module, the radio frequency communication module sends the infrared light status data in the local cache to the door controller.

2. The method according to claim 1, characterized in that, After the light curtain device wakes up the radio frequency communication module, and the radio frequency communication module sends the infrared light status data in the local cache to the door operator controller, the method further includes: During the charging window, if the light curtain device determines that there is an obstacle blocking the light based on the infrared light status data, the light curtain device controls the impedance adjustment circuit to change the load impedance of the receiving coil terminal. The power supply equipment monitors the output current of the transmitting coil in real time. When it detects a change in the output current caused by a change in the load impedance, the power supply equipment determines that an emergency blocking event has occurred and terminates the current charging window in advance, stopping the output of the high-frequency alternating magnetic field. After detecting the disappearance of the induced electrical signal corresponding to the receiving coil, the light curtain device wakes up the radio frequency communication module and sends safety alarm data indicating obstacle obstruction to the door controller.

3. The method according to claim 2, characterized in that, The step of the light curtain device controlling the impedance adjustment circuit to change the load impedance at the receiving coil terminal specifically includes: The light curtain device controls the impedance adjustment circuit to alternately turn on and off the bypass resistor connected across the two ends of the receiving coil according to a preset characteristic pulse code, so that the working impedance of the receiving coil switches frequently between a matched state and a mismatched state, thereby obtaining a reverse induced potential sequence corresponding to the characteristic pulse code.

4. The method according to claim 3, characterized in that, The power supply equipment monitors the output current of the transmitting coil in real time. When it detects a change in the output current caused by a change in the load impedance, the power supply equipment determines that an emergency blocking event has occurred. This process specifically includes: The power supply equipment continuously collects the primary AC current of the transmitting coil and extracts the amplitude envelope of the primary AC current; The power supply equipment analyzes the current drop-edge array based on the fluctuation pattern of the amplitude envelope. When it is determined that the time interval distribution of the current drop-edge array is consistent with the bit width protocol of the feature pulse code, it determines that the emergency blocking event has occurred.

5. The method according to claim 4, characterized in that, The step of resolving the current drop-edge array based on the fluctuation pattern of the amplitude envelope in the power supply equipment specifically includes: The power supply equipment calculates the current difference value of the amplitude envelope in two adjacent sampling periods; When the absolute value of the current difference exceeds the preset noise floor threshold and the continuous decrease duration of the amplitude envelope conforms to the preset falling edge characteristic, the current sampling time is marked as a valid edge trigger point. The power supply equipment collects all the valid edge trigger points within a preset judgment window period to obtain the current drop-off edge array.

6. The method according to claim 1, characterized in that, The step of switching from the charging time window to the communication time window specifically includes: The light curtain device, within the charging time window, does not rely on a local clock to drive the switching of the communication time window, but instead monitors the amplitude of the induced voltage across the receiving coil in real time. A hard synchronization interrupt signal is generated only when the light curtain device detects that the amplitude of the induced voltage has fallen below the minimum safe voltage threshold that maintains the normal operation of the impedance adjustment circuit; The light curtain device clears its local delay counter according to the hard synchronization interrupt signal, and uses the moment when the hard synchronization interrupt signal is triggered as the starting point for entering the communication time window.

7. The method according to claim 6, characterized in that, Within the communication window, the method further includes: When the radio frequency communication module sends the infrared light status data in the local buffer, it appends a communication end frame indicating that the buffer has been emptied to the end of the data stream. The power supply equipment enables the radio frequency sniffing channel during the communication time window to intercept the communication response packets returned by the gantry controller to the radio frequency communication module; Upon successfully intercepting the communication response packet, the power supply device terminates the communication time window in advance to release the remaining time allowance; The power supply equipment compensates the time allowance into the charging window of the next cycle and re-outputs the high-frequency alternating magnetic field.

8. A wireless elevator light curtain device, characterized in that, The wireless elevator light curtain device includes: one or more processors and a memory; the memory is coupled to the one or more processors, the memory is used to store computer program code, the computer program code including computer instructions, and the one or more processors call the computer instructions to cause the wireless elevator light curtain device to perform the method as described in any one of claims 1-7.

9. A computer program product containing instructions, characterized in that, When the computer program product is run on the wireless elevator light curtain device, the wireless elevator light curtain device performs the method as described in any one of claims 1-7.

10. A computer-readable storage medium comprising instructions, characterized in that, When the instruction is executed on the wireless elevator light curtain device, the wireless elevator light curtain device performs the method as described in any one of claims 1-7.

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