Electromagnetic lock device and control method thereof

Abstract

The present application relates to the field of electromagnetic control technology, and in particular to an electromagnetic lock device and a control method thereof. The present application scheme detects tag information through a reader / writer, and then controls the start of a constant current driving power supply to excite the electromagnet coil, and triggers the monitoring of the time when the electromagnet current reaches a preset state, and further detects the air gap between the electromagnet and the armature based on the time to determine whether it fits. The present application scheme cleverly utilizes the inductive physical characteristics of the electromagnet, and through constant current source excitation, before the electromagnet adsorbs the armature, the electromagnet is used as an air gap type inductive sensor for detection, and the detection of whether the electromagnet fits is converted into a parameter detection of the time when the current reaches a preset state for characterization. It only needs to execute the corresponding corresponding device control to determine whether the electromagnet and the armature are completely attracted and whether they are completely in a closed state. No additional sensors are required to determine whether they are tightly closed, and it can be intelligently connected with the production control system.

Description

Technical Field

[0001] The present application relates to the field of electromagnetic control technology, and in particular to an electromagnetic lock device and a control method thereof. Background Art

[0002] For example, in smart factories and intelligent production, safety requirements are very high. In order to ensure the personal safety of construction workers, the production line must be isolated from the production operators. Production operations can only be carried out under the premise of ensuring the safety of personnel. Therefore, before production operation, the production operation control system must obtain and determine that the isolation facilities have been completely closed, and there must be no virtual closure state. Among them, virtual closure means that it has been closed, but the closure state is not strict, and it is easy to be disturbed and opened, which can easily cause serious production accidents.

[0003] In the traditional solution, the isolation door is closed by electromagnet adsorption, but this method cannot accurately determine whether it is virtual closed. In addition, the traditional electromagnetic adsorption can only judge the current state through additional devices such as Hall sensors and photoelectric sensors, and cannot alarm for virtual closed state. The use of Hall sensors and photoelectric sensors undoubtedly increases the size of the equipment, and increases the installation and maintenance process and cost of the equipment. Summary of the invention

[0004] Based on this, the present application proposes an electromagnetic lock device and a control method thereof to address the above-mentioned problems, aiming to efficiently and intelligently control the electromagnetic lock, so as to improve the control accuracy and recognition accuracy of the electromagnetic lock device, and further improve the safety performance of the electromagnetic lock device.

[0005] On one hand, the present application provides a control method for an electromagnetic lock device, wherein the electromagnetic lock device includes an electromagnet, an armature, a wireless tag, a reader / writer, and a control circuit, and the method includes:

[0006] Control the reader to transmit an electromagnetic signal at a preset first frequency;

[0007] If the information returned by the wireless tag is detected, the control circuit is controlled to generate a constant current driving power supply and start detecting the electromagnet current information;

[0008] Monitor the time t when the electromagnet current reaches a preset state;

[0009] Detecting whether the electromagnet and the armature are in contact with each other based on the time t;

[0010] If they do not fit, the control output will correspond to the abnormal warning signal.

[0011] Preferably, the detecting whether the electromagnet and the armature are in contact with each other based on the time t comprises:

[0012] If the time t≥T, it is determined that the electromagnet is in contact with the armature, and a door-locking signal is controlled to be output;

[0013] wherein, T is the corresponding time threshold when the electromagnet is in contact with the armature, and satisfies:

[0014]

[0015] wherein, t is the time parameter when the current of the electromagnet reaches the preset state, N is the number of turns of the electromagnet coil, μ μ0 is the magnetic permeability of the electromagnet, S is the equivalent cross-sectional area, R is the resistance value of the load connected to the electromagnet, η is the ratio of the current when the current reaches the preset state to the constant current, and δ0 is the threshold value of the air gap size between the preset electromagnet and the armature.

[0016] Furthermore, the method further includes:

[0017] If the time t<T, the control circuit is controlled to stop generating the constant current driving power supply;

[0018] After a preset time interval, the control circuit is controlled to generate the constant current driving power supply again, and whether the electromagnet is in contact with the armature is detected according to the time t when the current of the electromagnet reaches the preset state;

[0019] Perform cyclic detection. If the number of cycles is greater than the preset number value, a preset door-locking abnormal warning signal is output.

[0020] Furthermore, the method further includes: if the time t≤αT, it is determined that there is a foreign object between the electromagnet and the armature, and a corresponding foreign object signal is controlled to be output, where α is a ratio threshold less than 1.

[0021] Furthermore, the method further includes:

[0022] Detect the signal strength returned by the wireless tag;

[0023] Estimate the relative distance between the reader and the wireless tag based on the signal strength:

[0024]

[0025] wherein, d is the estimated relative distance between the reader and the wireless tag, d0 is the preset reference distance, RSSI is the currently detected signal strength, RSSI0 is the signal strength corresponding to the reference distance 0, n is the signal attenuation parameter, and β is the corresponding adjustment parameter.

[0026] If the relative distance d is less than the preset distance value, and / or, if the change in the relative distance d within the preset period is less than the preset value, the control circuit is controlled to generate a constant current driving power supply, and the detection of the electromagnet current information is started.

[0027] Preferably, the method further comprises:

[0028] If it is detected that the electromagnet and the armature are in contact with each other, the relative distance between the reader and the wireless tag is controlled and detected;

[0029] If the relative distance between the reader / writer and the wireless tag increases suddenly, the control circuit is controlled to stop generating the constant current driving power supply and output a second warning signal.

[0030] A second aspect of the present application provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of any one of the above methods.

[0031] A third aspect of the present application provides an electromagnetic lock device, which includes an electromagnet, an armature, a wireless tag, a reader / writer, a control circuit, a controller, a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of any one of the methods described above.

[0032] Furthermore, the device comprises:

[0033] The electromagnet and the armature are arranged opposite to each other, the reader / writer and the wireless tag are arranged opposite to each other, the electromagnet and the reader / writer are fixed on one side, and the armature and the wireless tag are fixed on the other side;

[0034] Preferably, the control circuit includes a constant current source module, a high-precision load resistor, and a current detection module, wherein: the output end of the constant current source module is connected to one end of the electromagnet coil, the signal control input end of the constant current source module is connected to the external control signal, the other end of the electromagnet coil is connected to the high-precision load resistor, the current detection module includes two input ends, which are respectively connected to the two ends of the high-precision load resistor, and the output end of the current detection module is connected to the analog-to-digital converter.

[0035] The solution provided in the above application detects the tag information through the reader / writer, and then controls the start of the constant current driving power supply to excite the electromagnet coil, and triggers the monitoring of the time when the electromagnet current reaches a preset state. Further based on the time, the air gap between the electromagnet and the armature can be directly detected to determine whether it fits. The solution of this application cleverly utilizes the inductive physical characteristics of the electromagnet, and through constant current source excitation, converts the detection of whether the electromagnet fits into the detection of the time parameter of the current reaching the preset state for characterization. It only needs to execute the corresponding corresponding device control to determine whether the electromagnet and the armature are completely attracted and whether they are completely in the closed state. No additional sensors are required to determine whether they are closed tightly, and it can be intelligently connected with the production control system.

[0036] Compared with the traditional scheme using devices such as Hall or photoelectric sensors, the above scheme of the present application reduces the use of components, reduces the cost of the product, and enhances stability. The above control logic and method of the present application also has the characteristics of high detection accuracy. It can normally identify a business card sandwiched between the magnets, iron filings and other foreign objects, and can ensure the isolation of the production actuator in actual production applications.

[0037] Furthermore, the detection control circuit used in the present application has the characteristics of low cost, easy implementation, high sensitivity, etc., which greatly improves the accuracy of detection. The card reader recognition RFID tag technology used can give an early warning when abnormal opening occurs, and the relative distance is obtained by judging the strength of the signal and then controlled, which helps to improve the detection accuracy while improving safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] in:

[0040] Figure 1 is a flow chart of a control method of an electromagnetic lock device in one embodiment;

[0041] Figure 2 A control circuit diagram of an electromagnetic lock device in one embodiment;

[0042] Figure 3 is a schematic structural diagram of an electromagnetic lock device in one embodiment;

[0043] Figure 4 FIG. 4 is a structural block diagram of a computer device in one embodiment. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The terms "include", "comprising" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device comprising a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices. In the claims, specification and drawings of the present application, relational terms such as "first" and "second" are merely used to distinguish one entity / operation / object from another entity / operation / object, and do not necessarily require or imply any such actual relationship or order between these entities / operations / objects.

[0046] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The occurrence of the phrase at various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0047] In one embodiment, if Figure 1 The flowchart of an electromagnetic lock device of the present application is shown, wherein the electromagnetic lock device includes an electromagnet, an armature, a wireless tag, a reader / writer, and a control circuit. Specifically, a wire is wound around the outside of the iron core of the electromagnet, and a magnetic field can be generated when energized, which is equivalent to an inductor in the circuit. The armature is an iron block adsorbed by the magnetic field of the electromagnet, the wireless tag includes a storage area, and components that can be powered by radio frequency wireless and read and write to the storage area, and the card reader includes an antenna module, and the wireless tag can be read and written through the antenna. Further, the method includes:

[0048] S10, controlling the reader to transmit an electromagnetic signal at a preset first frequency.

[0049] Preferably, the reader / writer in the present application adopts near field communication (NFC) to communicate and read / write with the wireless tag. The reader / writer in the present application is directly or indirectly connected to the controller, and the controller controls the reader / writer to transmit electromagnetic wave signals at a preset first frequency. After receiving the control signal, the reader / writer transmits electromagnetic signals by radiating electromagnetic waves into the air through the antenna at the first preset frequency. The wireless tag receives the electromagnetic signal released by the card reader through the antenna, receives the instructions of the card reader, reads and writes the stored data, and transmits the corresponding signal to the reader / writer through the antenna. Preferably, the wireless tag is an RFID wireless tag, and the first frequency can be from several megahertz to hundreds of megahertz. Preferably, in one embodiment, the first frequency is 13.56MHz.

[0050] S11, if the information returned by the wireless tag is detected, the control circuit is controlled to generate a constant current driving power supply, and the detection of the electromagnet current information is started.

[0051] Preferably, in an embodiment of the present application, if the reader receives a signal returned by the wireless tag, it can be determined that the armature is close to the electromagnet, or the bevel is within a preset distance range near the electromagnet. At this time, the controller controls the control circuit to generate a constant current drive power supply and starts detecting the electromagnet current information.

[0052] Specifically, in the embodiment of the present application, the implementation principle of the present application scheme is: before the electromagnet is not attracted to the armature, the electromagnet is used as an air gap type inductive sensor for detection, and the air gap type sensor is mainly composed of an iron core, a coil, and an armature. The specific deduction and implementation principle is as follows:

[0053] According to the principle of magnetic circuit knowledge, the coil inductance can be expressed as:

[0054]

[0055] Where N is the number of turns of the coil, R m is the total magnetic resistance of the magnetic circuit. According to Ohm's law of the magnetic circuit, the total magnetic resistance of the magnetic circuit is the sum of the magnetic resistances of the core magnetic circuit, the armature magnetic circuit and the air gap magnetic circuit, as shown in the following formula:

[0056]

[0057] In the formula l 1 、l 2. A 1. A 2. μ 1 , μ 2 are the length, cross-sectional area and magnetic permeability of the core and armature magnetic circuits respectively; δ、A , μ0 are the length, equivalent cross-sectional area and magnetic permeability of the air gap respectively. The iron core generally works in a non-saturated state, and its magnetic permeability is much greater than the magnetic permeability of the air. Therefore, the magnetic resistance of the armature core is much smaller than the magnetic resistance of the air gap, so the coil inductance can be equivalent to:

[0058]

[0059] In the above coil inductance equivalent formula, when the number of turns N of the core coil and the equivalent cross-sectional area A of the air gap remain unchanged, the magnetic permeability of the air gap is generally considered to be unchanged, and the inductance of the coil is linearly inversely proportional to the length δ of the air gap. The larger the gap, the smaller the inductance. Therefore, the present application scheme uses an excitation power supply to check the distance between the core coil and the armature to detect the change in the inductance of the electromagnet coil in the early stage of power-on. The change in the distance between the core and the armature causes a change in the magnetic resistance of the air gap, thereby changing the inductance of the coil. When the electromagnet coil is connected to the measurement circuit, the change in the inductance of the coil can be converted into a change in current, thereby achieving the purpose of measuring the air gap distance, specifically including:

[0060] By controlling the control circuit to generate a constant current drive power supply, the constant current drive power supply can be a constant current or voltage drive source, and the constant current drive power supply energizes the electromagnet coil. At this time, the constant current drive source can be used as an inductive excitation source for the electromagnet, and the electromagnet and the coil generate an inductive effect under the constant current excitation. Further, when the control generates constant current source excitation, the drive circuit is turned on to start timing, and the current value is detected to determine the time when the current reaches a preset state, thereby indirectly obtaining and characterizing the current inductance, thereby determining whether the current electromagnet and the armature are in contact, wherein the preset state can be a stable, saturated cutoff state.

[0061] Compared with the traditional solution, the present application does not simply treat the electromagnet as a device for attracting the armature, and generates a magnetic field by energizing the electromagnet to attract the armature. Instead, before the electromagnet attracts the armature, the electromagnet is used as an air gap inductive sensor for detection, and the inductive current is generated by the driving circuit. The electromagnet driving circuit is mainly composed of a constant current source drive, a current detection circuit and a processor (MCU). The constant current source provides a current excitation source for the iron core coil when detecting the air gap distance, and is the function of the electromagnet magnetic field when performing the adsorption action.

[0062] S12, monitoring the time t when the electromagnet current reaches a preset state.

[0063] Further, if Figure 2As shown, a control drive circuit is provided in an embodiment of the present application, wherein the circuit includes a constant current source module, a high-precision load resistor, and a current detection module, wherein the output end of the constant current source module is connected to one end of the electromagnet coil, the signal control input end of the constant current source module is connected to an external control signal (MCU control signal), the other end of the electromagnet coil is connected to the high-precision load resistor, the current detection module includes two input ends, which are respectively connected to the two ends of the high-precision load resistor, and the output end of the current detection module is connected to an analog-to-digital converter.

[0064] The above scheme of the present application is connected in series with a high-precision load resistor R. At this time, the circuit can be equivalent to an LR circuit. In the LR circuit, it takes a certain process for the voltage and current of the inductor to reach a stable state for the change of the external excitation (DC) source. Its waveform conforms to the exponential change, and the inductor current rises in an exponential curve. When the control generates constant current source excitation, the drive circuit is turned on to start the timing, and the time when the current value reaches the preset state is detected to determine whether the current electromagnet and the armature are in contact. Preferably, during current detection, the current change in the electromagnet is converted into a voltage value, and the time period of the current change is recorded by a timer in the processor (MCU), so as to obtain the time parameter, and use it to detect the calculation and judgment of the gap distance.

[0065] Furthermore, the constant current source is used to provide driving current to the electromagnet. When in the detection state, it provides a constant current as the excitation source of the inductor. It is controlled by the processor (MCU) to turn on and off and control the constant current output current. The current detection module uses a high-precision resistor to collect the voltage across its two ends and converts it into a voltage value using the analog-to-digital converter (ADC) of the processor (MCU), through the formula: I = U / R , calculate the current value when measuring the air gap distance. The processor (MCU) starts measuring the current when the constant current source is turned on. When the current reaches the preset state, it can determine whether there is a foreign object gap between the electromagnet and the armature, with high detection accuracy.

[0066] S13, detecting whether the electromagnet and the armature are in contact with each other based on the time t.

[0067] Preferably, in one embodiment of the present application, the detecting whether the electromagnet fits the armature based on the time t includes:

[0068] If the time t≧T, it is determined that the electromagnet is in contact with the armature, and a door locking signal is output;

[0069] Among them, T is the corresponding time threshold when the electromagnet and the armature are in contact, satisfying:

[0070]

[0071] where t is the time parameter for the electromagnet current to reach the preset state, N is the number of turns of the electromagnet coil, is the magnetic permeability of the electromagnet, S is the equivalent cross-sectional area, R is the value of the load resistance connected to the electromagnet, δ 0 is the threshold value of the air gap size between the preset electromagnet and the armature, and η is the ratio of the current to the constant current when the preset current reaches the preset state: η = I 稳 / I 恒 * 100%, where the parameters can be set according to the actual situation. For example, when the detected current reaches 90%, 95, 99%, 99.5% of the constant current, it is used as the judgment value.

[0072] S14. If not fitted, control the output of the corresponding abnormal warning signal.

[0073] Preferably, in an embodiment of the present application, the method for judging the fitting method and the corresponding output control includes:

[0074] If the time t < T, control the control circuit to stop generating the constant current drive power supply;

[0075] After a preset time interval, control the control circuit to generate the constant current drive power supply again, and detect whether the electromagnet and the armature are fitted according to the time t when the electromagnet current reaches the preset state;

[0076] Perform cyclic detection. If the number of cycles is greater than the preset number value, output a preset abnormal warning signal for locking the door.

[0077] Further, the method further includes: if the time t ≤ αT, it is determined that there is a foreign object between the electromagnet and the armature, and control the output of the corresponding foreign object signal, where α is a proportional threshold less than 1.

[0078] Further, the solution of the present application further includes a second safety warning function, and the method further includes:

[0079] If it is detected that the electromagnet and the armature are in contact, the control detects the relative distance between the reader and the wireless tag; if the relative distance between the reader and the wireless tag suddenly increases, the control circuit is controlled to stop generating a constant current driving power supply and output a second warning signal. It can be understood that in the contact state, the electromagnet and the armature are adsorbed. At this time, the present application determines whether there is an illegal door lock opening (such as violent door opening) by the relative distance between the reader and the wireless tag. If it is detected that the relative distance between the reader and the wireless tag suddenly increases, it is determined to be an illegal door lock opening, and the control circuit is controlled to stop generating a constant current driving power supply, so that the subsequent device can detect the next process cycle, and output a second warning signal for warning. The second warning signal is different from the aforementioned abnormal warning signal, which improves the overall stability and safety.

[0080] The solution provided in the above application detects the tag information through the reader / writer, and then controls the start of the constant current driving power supply to excite the electromagnet coil, and triggers the monitoring of the time when the electromagnet current reaches a preset state. Further based on the time, the air gap between the electromagnet and the armature can be directly detected to determine whether it fits. The solution of this application cleverly utilizes the inductive physical properties of the electromagnet. Before the electromagnet adsorbs the armature, the electromagnet is used as an air gap type inductive sensor for detection. Through constant current source excitation, the detection of whether the electromagnet fits is converted into the detection of the time parameter when the current reaches the preset state for characterization. It only needs to execute the corresponding corresponding device control to determine whether the electromagnet and the armature are completely attracted and whether they are completely in the closed state. No additional sensors are required to determine whether they are closed tightly, and it can be intelligently connected with the production control system.

[0081] Compared with the traditional solution using devices such as Hall or photoelectric sensors, the above solution of this application reduces the use of components, reduces product costs, and enhances stability. The above control logic and method of this application also has the characteristics of high detection accuracy. It can normally identify a business card sandwiched between the magnets, iron filings and other foreign objects. In actual production applications, it can ensure the isolation of the production actuator.

[0082] Further preferably, in one embodiment, based on the above solution, in order to further improve the accuracy of system detection and control, the solution of the present application further detects the returned signal information, and only triggers the subsequent detection and control steps when the returned signal reaches a preset condition. Specifically, the method also includes:

[0083] S20: Detect the strength of the signal received from the wireless tag.

[0084] Specifically, the RFID tag receives a query signal from the reader and reflects back a signal containing corresponding information. The reader receives the signal for processing and / or hands it over to the corresponding controller or signal processor for signal processing, including:

[0085] Signal amplification: The reader's receiving antenna receives the reflected signal and usually needs to amplify this weak signal through a low noise amplifier (LNA).

[0086] Analog-to-digital conversion: The amplified signal is converted into a digital signal for further digital signal processing.

[0087] Digital Signal Processing: The digital signal processor (DSP) or microcontroller processes the received digital signal, including filtering and demodulation, etc. The DSP or microcontroller further analyzes the amplitude of the signal and converts it into a signal strength value in dBm (decibels per milliwatt).

[0088] RSSI calculation: The signal strength is calculated based on the signal information: RSSI=10log10(SP)+OffsetRSSI, where SignalPowe is the signal power value and OffsetRSSI is a preset system-specific calibration value.

[0089] S21. Estimate the relative distance between the reader and the tag based on the signal strength.

[0090]

[0091] Wherein, d is the estimated relative distance between the reader and the tag, d0 is the preset reference distance, RSSI is the currently detected signal strength, RSSI0 is the signal strength corresponding to the reference distance d0, n is the signal attenuation parameter, and β is the corresponding adjustment parameter.

[0092] S22. If the relative distance d is less than a preset distance value, and / or the change in the relative distance d within a preset period is less than a preset value or the detected signal is relatively stable, control the control circuit to generate a constant current drive power supply and start detecting the electromagnet current information.

[0093] In the above implementation, the present application solution also includes a further electromagnetic lock device implementation method, comprising the following steps:

[0094] S31, the electromagnetic lock drives the movable door to close after receiving the door locking signal;

[0095] S32, the card reader reads the wireless tag signal;

[0096] S33: If the card reader does not obtain the wireless tag signal, return to step S2;

[0097] If the card reader determines the validity of the identity information on the wireless tag after acquiring the information on the wireless tag, and if it is valid, the state control feedback device outputs an identity authentication success signal, and executes step S4;

[0098] S34, judging whether the electromagnet and the armature are completely fitted; if not, returning to step S1; if they are completely fitted, controlling the output to output the door lock state;

[0099] S35. When the electromagnetic lock receives a door opening signal, it performs a door opening action when no abnormal signal is received, and sends an alarm signal when an abnormal signal is received.

[0100] It should be understood that, although the various steps in the above-mentioned scheme flow and the flowchart in the accompanying drawings are shown in sequence, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a part of the steps may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0101] In one embodiment, Figure 3 As shown, a schematic diagram of an electromagnetic lock device is provided as a second aspect of the present application, wherein the electromagnetic lock device includes an electromagnet, an armature, a wireless tag, a reader / writer, a control circuit, a controller, a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of any one of the above methods.

[0102] Furthermore, the electromagnetic lock device comprises:

[0103] The electromagnet and the armature are arranged opposite to each other, and the reader and the wireless tag are arranged opposite to each other. The electromagnet and the reader are fixed on one side, and the armature and the wireless tag are fixed on the other side. Preferably, the armature and the wireless tag are combined and installed on the movable door, and the electromagnet and the card reader and the logic controller are fixed on the door frame. The device is powered by an external power supply through a connector, and control signal input and status output are provided.

[0104] Preferably, the control circuit includes a constant current source module, a high-precision load resistor, and a current detection module, wherein: the output end of the constant current source module is connected to one end of the electromagnet coil, the signal control input end of the constant current source module is connected to the external control signal, the other end of the electromagnet coil is connected to the high-precision load resistor, the current detection module includes two input ends, which are respectively connected to the two ends of the high-precision load resistor, and the output end of the current detection module is connected to the analog-to-digital converter.

[0105] In one embodiment, the present application further provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor performs the following steps:

[0106] Control the reader to transmit an electromagnetic signal at a preset first frequency;

[0107] If the information returned by the wireless tag is detected, the control circuit is controlled to generate a constant current driving power supply and start detecting the electromagnet current information;

[0108] Monitor the time t when the electromagnet current reaches a preset state;

[0109] Detecting whether the electromagnet and the armature are in contact with each other based on the time t;

[0110] If they do not fit, the control output will correspond to the abnormal warning signal.

[0111] In one embodiment, Figure 4 The present application also provides an electromagnetic lock control computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0112] Control the reader to transmit an electromagnetic signal at a preset first frequency;

[0113] If the information returned by the wireless tag is detected, the control circuit is controlled to generate a constant current driving power supply and start detecting the electromagnet current information;

[0114] Monitor the time t when the electromagnet current reaches a preset state;

[0115] Detecting whether the electromagnet and the armature are in contact with each other based on the time t;

[0116] If they do not fit, the control output will correspond to the abnormal warning signal.

[0117] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0118] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0119] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for controlling an electromagnetic lock device, characterized in that: The electromagnetic lock device includes an electromagnet, an armature, a wireless tag, a reader, and a control circuit. The method includes: Controlling the reader to transmit an electromagnetic signal at a preset first frequency; If the information returned by the wireless tag is detected, controlling the control circuit to generate a constant current drive power supply and enabling the detection of the electromagnet current information; Monitoring the time t when the electromagnet current reaches a preset state; Detecting whether the electromagnet and the armature are in contact based on the time t; If not in contact, controlling the output of a corresponding abnormal warning signal; The method further includes: If the time t ≥ T, determining that the electromagnet and the armature are in contact and controlling the output of a door locking signal; where T is the corresponding time threshold when the electromagnet and the armature are in contact, satisfying: Among them, t is the time parameter for the electromagnet current to reach the preset state, N is the number of turns of the electromagnet coil, μ 0 is the magnetic permeability of the electromagnet, S is the equivalent cross-sectional area, R is the load resistance value connected to the electromagnet, η is the ratio of the current to the constant current when the preset judgment current reaches the preset state, δ 0 is the preset air gap size threshold between the electromagnet and the armature.

2. The method according to claim 1, characterized in that The method further includes: If the time t < T, controlling the control circuit to stop generating the constant current drive power supply; After a preset time interval, controlling the control circuit to generate the constant current drive power supply again, and detecting whether the electromagnet and the armature are in contact according to the time t when the electromagnet current reaches a preset state; Performing a loop detection. If the loop count is greater than a preset count value, outputting a preset door locking abnormal warning signal.

3. The method according to claim 1, characterized in that The method further includes: If the time t ≤ αT, determining that there is a foreign object between the electromagnet and the armature and controlling the output of a corresponding foreign object signal, where α is a proportional threshold less than 1.

4. The method according to claim 1, characterized in that The method further includes: Detecting the signal strength of the signal returned by the wireless tag received; Estimating the relative distance between the reader and the tag based on the signal strength: Where d is the estimated relative distance between the reader and the tag, d0 is a preset reference distance, RSSI is the currently detected signal strength, RSSI0 is the signal strength corresponding to the reference distance d0, n is the signal attenuation parameter, and β is the corresponding adjustment parameter; If the relative distance d is less than a preset distance value, and / or, if the change in the relative distance d within a preset period is less than a preset value, controlling the control circuit to generate a constant current drive power supply and enabling the detection of the electromagnet current information.

5. The method according to any one of claims 1 to 4, characterized in that: The method further includes: If it is detected that the electromagnet and the armature are in contact, controlling the detection of the relative distance between the reader and the wireless tag; If the relative distance between the reader and the wireless tag suddenly increases, controlling the control circuit to stop generating the constant current drive power supply and outputting a second warning signal.

6. A computer-readable storage medium storing a computer program, which when executed by a processor causes the processor to perform the steps of the method according to any one of claims 1 to 5.

7. An electromagnetic lock device including an electromagnet, an armature, a wireless tag, a reader, a control circuit, a controller, a memory, and a processor. The memory stores a computer program, which when executed by the processor causes the processor to perform the steps of the method according to any one of claims 1 to 5.

8. The device according to claim 7, characterized in that The device includes: The electromagnet and the armature are disposed opposite to each other, the reader and the wireless tag are disposed opposite to each other, the electromagnet and the reader are fixed on one side, and the armature and the wireless tag are fixed on the other side.

9. The device according to claim 7, characterized in that The control circuit includes a constant current source module, a high-precision load resistor, and a current detection module, wherein: The output end of the constant current source module is connected to one end of the electromagnet coil, the signal control input end of the constant current source module is connected to the external control signal, the other end of the electromagnet coil is connected to the high-precision load resistor, the current detection module includes two input ends, which are respectively connected to the two ends of the high-precision load resistor, and the output end of the current detection module is connected to the analog-to-digital converter.

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