Fatigue driving intervention method and system based on head electrical stimulation

Abstract

The invention discloses a fatigue driving intervention method and system based on head electric pulse stimulation, and relates to the technical field of fatigue driving intervention, and the method comprises the steps: collecting the scalp micro-motion frequency and scalp-electrode impedance change of a driver through a head-mounted sensing device, and obtaining an original physiological state signal; calculating a current fatigue index according to the original physiological state signal, wherein the reduction of scalp micro-motion frequency and the increase of impedance fluctuation amplitude respectively correspond to the increase of fatigue degree and the aggravation of attention distraction; continuously comparing the fatigue index with a dynamically adjusted physiological threshold, and when the fatigue index exceeds the physiological threshold and maintains a preset duration, generating a first intervention triggering condition; and whether a second intervention triggering condition or a third intervention triggering condition is generated or not is judged by combining an intervention mode preset by a user, the continuous running time of the vehicle and a manual triggering instruction, and an intervention enabling signal is output based on the logic relation of the first intervention triggering condition, the second intervention triggering condition and the third intervention triggering condition.

Description

Technical Field

[0001] This invention relates to the field of fatigue driving intervention technology, and in particular to a fatigue driving intervention method and system based on head electrical stimulation. Background Technology

[0002] Fatigue driving intervention technology refers to a class of intelligent safety technologies that monitor the driver's physiological state or driving behavior, and upon identifying signs of fatigue, proactively employ physical, auditory, visual, or neural stimulation methods to promptly awaken the driver's attention and encourage rest. This aims to prevent traffic accidents caused by slowed reaction time, misjudgment, or brief sleep due to fatigue. Therefore, how to utilize advanced technologies to improve the intelligence and safety of fatigue driving intervention has become one of the most pressing issues to be addressed.

[0003] In the field of fatigue driving intervention, existing technologies mostly rely on a single external behavioral signal, which is easily affected by lighting, occlusion, driving habits or vehicle type. They cannot truly reflect the fatigue state of the driver's central nervous system, resulting in a high false alarm rate or serious missed alarms. Moreover, most systems use fixed time thresholds or general fatigue models, without considering individual physiological differences, circadian rhythms or historical response behaviors, making it difficult to achieve on-demand intervention. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a fatigue driving intervention method based on head electrical stimulation to solve the problems of existing technologies that mostly rely on a single external behavioral signal, are easily affected by light, occlusion, driving habits or vehicle type, and cannot truly reflect the fatigue state of the driver's central nervous system, resulting in high false alarm rates or serious missed alarms. Moreover, most systems use fixed time thresholds or general fatigue models, without considering individual physiological differences, circadian rhythms or historical response behaviors, making it difficult to achieve on-demand intervention.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a fatigue driving intervention method based on head electrical stimulation, comprising: The driver's scalp micro-movement frequency and scalp-electrode impedance changes are collected by a head-mounted sensing device to obtain raw physiological state signals. The current fatigue index is calculated based on the original physiological state signals, where a decrease in scalp micro-movement frequency and an increase in impedance fluctuation amplitude correspond to an increase in fatigue level and an increase in attention distraction, respectively. The fatigue index is continuously compared with a dynamically adjusted physiological threshold. When the fatigue index exceeds the physiological threshold and remains at the preset duration, a first intervention trigger condition is generated. Based on the user's pre-set intervention mode, vehicle continuous running time, and manual trigger command, determine whether to generate a second or third intervention trigger condition, and output an intervention enable signal based on the logical relationship between the first, second, and third intervention trigger conditions. After receiving the intervention enable signal, the contact impedance between the headgear electrode and the scalp is detected. Only when the contact impedance is in the effective conduction range, a pulse width modulated electrical pulse is output to a specific area of ​​the head according to the stimulation intensity level set by the user. At the same time, the number of electrical stimulation triggers per unit time is accumulated and the upper limit is locked. The intervention mode type, time count value, historical stimulation records, and electrode contact status are transmitted to the serial port touch screen via serial communication and displayed on the screen in real time for user interaction and configuration.

[0007] As a preferred embodiment of the fatigue driving intervention method based on head electrical stimulation described in this invention, the step of acquiring the driver's scalp micro-movement frequency and scalp-electrode impedance changes through a head-mounted sensing device to obtain the original physiological state signal includes the following steps: After the driver puts on the smart headgear with integrated flexible electrodes, the system initiates the physiological signal acquisition process; In the time window Inside, a micro-vibration sensor continuously detects minute displacements on the scalp surface and counts the number of times the displacement signal crosses the zero point, denoted as . The frequency of scalp micro-movements is thus calculated. ; An AC excitation voltage with constant amplitude and fixed frequency is applied to the electrodes. Measurement of loop current amplitude Calculate the current scalp-electrode contact impedance amplitude according to Ohm's law. ; For continuous Impedance value per sampling period Calculate the sliding window standard deviation to obtain the impedance fluctuation amplitude. ; Will and The synchronous output forms the original physiological state signal, which is used for subsequent fatigue state assessment.

[0008] As a preferred embodiment of the fatigue driving intervention method based on head electrical stimulation described in this invention, the specific steps for calculating the current fatigue index based on the original physiological state signal are as follows: The baseline value for the scalp micro-movement frequency in a waking state is set to... For the measured frequency Perform normalization and calculate the first sub-score. The expression is: ; Set the reference threshold for impedance fluctuation as For the measured fluctuation amplitude Perform amplitude limiting and normalization, and calculate the second sub-score. The expression is: ; Introducing weighting coefficients and ,in Characterizing the contribution of fretting frequency to fatigue. Characterize the contribution of distraction to fatigue; The current fatigue index is calculated by combining the two sub-scores. The expression is: ; in, , , , All configurations are performed by the user via a serial port touchscreen or loaded using factory default values ​​during the system initialization phase.

[0009] As a preferred embodiment of the fatigue driving intervention method based on head electrical stimulation described in this invention, the following steps are taken: Continuously comparing the fatigue index with a dynamically adjusted physiological threshold; when the fatigue index exceeds the physiological threshold and remains there for a preset duration, a first intervention trigger condition is generated. Set the initial physiological threshold as ; Introducing environmental correction factors The time of day is determined based on the time of vehicle startup: if the startup time is at night, then... ,otherwise =0; Introducing behavioral feedback correction factors The system records the past After the intervention, if the driver stops to rest within 5 minutes, and the number of times they do not rest exceeds 50%, then... ,otherwise =0; Dynamically update physiological thresholds for: ; The system continuously monitors the fatigue index. If continuous Each sampling period satisfies > If the condition is met, the continuous over-limit condition is determined, and the first intervention trigger condition is generated.

[0010] As a preferred embodiment of the fatigue driving intervention method based on head electrical stimulation described in this invention, the steps of determining whether to generate a second or third intervention trigger condition by combining the user-preset intervention mode, the vehicle's continuous running time, and the manual trigger command, and outputting an intervention enable signal based on the logical relationship between the first, second, and third intervention trigger conditions, are as follows: The system reads the intervention mode identifier set by the user via the serial port touch screen. Its value is , or ; like Then the vehicle running timer will be started, and when the cumulative running time reaches the preset threshold... At that time, a second intervention trigger condition is generated; like Then, it continuously monitors the physical button signals on the headgear. When a valid pressing action is detected and the duration is greater than the de-shake threshold, a third intervention trigger condition is generated. like When either the first intervention trigger condition or the second intervention trigger condition is met, an intervention enable signal is output. Once a manual trigger command is detected, a third intervention trigger condition is immediately generated, and the intervention enable signal is forcibly set while the running timer is cleared.

[0011] As a preferred embodiment of the fatigue driving intervention method based on head electrical stimulation described in this invention, the steps include: after receiving the intervention enable signal, detecting the contact impedance between the headgear electrodes and the scalp; only when the contact impedance is within the effective conduction range, outputting a pulse width modulated electrical pulse to a specific area of ​​the head according to the stimulation intensity level set by the user; and simultaneously accumulating the number of electrical stimulation triggers per unit time and implementing an upper limit lock. The specific steps are as follows: Remeasure current contact impedance ; Set the effective conduction interval as ,like ≤ ≤ If so, the electrode contact is considered good; If there is poor contact, the electrical stimulation output will be prohibited, and a message indicating that the electrodes are not in contact will be displayed on the serial port screen. If the contact is good, the user-defined stimulation intensity level will be read. , The integers are 1 to 5, corresponding to five levels of constant output current; Drive boost circuit and The bridge outputs bipolar square wave pulses with a fixed frequency within a safe range and a preset duration for each stimulus. ; Meanwhile, the system maintains an hourly trigger counter. Before each successful electrical stimulation output, check If the condition is met, then the stimulus is applied and the action is taken. Otherwise, it will enter a locked state until it automatically resets at the start of the next hour.

[0012] As a preferred embodiment of the fatigue driving intervention method based on head electrical stimulation described in this invention, the steps of transmitting the intervention mode type, time count value, historical stimulation record, and electrode contact status to a serial port touch screen via serial communication and displaying them on the screen in real time for user interaction and configuration are as follows: The main control module packages the currently running data in a fixed frame format, including: Intervention mode identifier, remaining runtime, timestamps of the last five interventions, and current contact impedance value. Hourly trigger count And the lock flag; Data frames are sent to a serial touch display at a baud rate of 9600 via a UART interface. The display has an 800×480 resolution, capacitive touch function, and supports the Taojingchi scripting language. After receiving the data frame, the display parses each field and updates it in the preset UI page accordingly, including: The colors of the mode icon, countdown progress bar, time record in the list control, and status indicator light are as follows: green indicates good contact, and red indicates abnormality. When the user touches the intensity adjustment slider, the display generates... instruction; When the user clicks the mode switch button, generate instruction; After receiving the instruction, the main control module writes the new parameters into the internal 1024-byte EEPROM storage area and immediately applies them to the next intervention judgment and output process.

[0013] Secondly, the present invention provides a fatigue driving intervention system based on head electrical stimulation, comprising: The system includes a physiological signal acquisition module, a fatigue index calculation module, a dynamic threshold determination module, a dual-mode intervention decision-making module, a safe electrical stimulation execution module, and a human-computer interaction display module. The physiological signal acquisition module is used to acquire the driver's scalp micro-movement frequency and scalp-electrode impedance changes in real time through a head-mounted sensing device, and generate raw physiological state signals. The fatigue index calculation module is used to calculate the current fatigue index, which represents the degree of fatigue and the degree of attention distraction, based on the original physiological state signal and in combination with a preset benchmark value and weighting coefficient. The dynamic threshold determination module is used to continuously compare the current fatigue index with the dynamic physiological thresholds of the fusion environment time factor and the user behavior feedback factor, and generate the first intervention trigger condition when the excessive duration condition is met. The dual-mode intervention decision module is used to output an intervention enable signal according to a preset priority logic, based on the intervention mode set by the user, the continuous running time of the vehicle, the manual trigger command, and the first intervention trigger condition. The safe electrical stimulation execution module is used to detect the electrode contact status after receiving the intervention enable signal, output head electrical stimulation according to the intensity set by the user only when the contact is effective, and lock the upper limit of the number of triggers per unit time. The human-computer interaction display module is used to receive user configuration parameters through a serial port touch screen and display the intervention mode, timing status, historical records and electrode contact status in real time, so as to realize two-way interaction and persistent parameter storage.

[0014] Thirdly, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program is executed by the processor, it implements any step of the fatigue driving intervention method based on head electrical stimulation as described in the first aspect of the present invention.

[0015] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the fatigue driving intervention method based on head electrical stimulation as described in the first aspect of the present invention.

[0016] The beneficial effects of this invention are as follows: By integrating the dual-dimensional physiological signals of scalp micro-motion frequency and impedance fluctuation, a fatigue index model with individual adaptability is constructed. A dual correction mechanism based on environmental time period and user behavior feedback is introduced to dynamically adjust the intervention threshold, effectively improving the accuracy and timeliness of fatigue identification. Simultaneously, a three-state intervention logic of active timing, passive manual, and hybrid collaboration is adopted, balancing automated early warning and user autonomous control. Combined with a safe electrical stimulation execution architecture based on contact impedance detection, current intensity grading, and trigger count locking per unit time, the safety and compliance of head electrical stimulation in vehicle scenarios are ensured. Furthermore, a serial port touchscreen enables visualized parameter configuration and real-time status feedback, forming a closed-loop system. This effectively solves the problems of high false alarm rate, delayed response, lack of safety guarantees, and insufficient human-machine collaboration in existing fatigue driving intervention technologies. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of the fatigue driving intervention method based on head electrical stimulation in Example 1.

[0019] Figure 2 This is a schematic diagram of the fatigue driving intervention system based on head electrical stimulation in Example 1. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0023] Example, refer to Figure 1 and Figure 2 This embodiment of the invention provides a fatigue driving intervention method based on head electrical stimulation, comprising: S1. Collect the driver's scalp micro-movement frequency and scalp-electrode impedance changes through a head-mounted sensing device to obtain raw physiological state signals. Furthermore, once the driver wears a smart headgear with integrated flexible electrodes, the system initiates the physiological signal acquisition process. In the time window Inside, a micro-vibration sensor continuously detects minute displacements on the scalp surface and counts the number of times the displacement signal crosses the zero point, denoted as . The frequency of scalp micro-movements is thus calculated. ; Simultaneously, an AC excitation voltage with constant amplitude and fixed frequency is applied to the electrodes. Measurement of loop current amplitude Calculate the current scalp-electrode contact impedance amplitude according to Ohm's law. ; For continuous Impedance value per sampling period Calculate the sliding window standard deviation to obtain the impedance fluctuation amplitude. ; Will and Synchronous output constitutes the original physiological state signal for subsequent fatigue state assessment; It should be noted that by synchronously collecting the scalp micro-movement frequency and impedance fluctuation amplitude within a unified time window, and quantifying them based on the zero-point crossing method and Ohm's law, dual physiological indicators reflecting central alertness and attention stability can be obtained in a low-cost, non-invasive manner. This avoids reliance on external signals that are easily affected by environmental interference, such as cameras or steering wheel behavior, and effectively improves the robustness and early sensitivity of fatigue detection.

[0024] S2. Calculate the current fatigue index based on the original physiological state signals, where the decrease in scalp micro-movement frequency and the increase in impedance fluctuation amplitude correspond to the increase in fatigue level and the intensification of attention distraction, respectively. Furthermore, a baseline value is set for the frequency of scalp micro-movements in a conscious state. For the measured frequency Perform normalization and calculate the first sub-score. The expression is: ; Set the reference threshold for impedance fluctuation as For the measured fluctuation amplitude Perform amplitude limiting and normalization, and calculate the second sub-score. The expression is: ; Introducing weighting coefficients and ,in Characterizing the contribution of fretting frequency to fatigue. Characterize the contribution of distraction to fatigue; The current fatigue index is calculated by combining the two sub-scores. The expression is: ; in, , , , All configurations are performed by the user via a serial touchscreen or loaded using factory default values ​​during the system initialization phase. It should be noted that the fatigue index calculation model based on normalized sub-score weighted fusion not only maps the decrease in micro-motion frequency and the increase in impedance fluctuation to quantifiable fatigue and distraction levels, but also allows users to configure weights and benchmark thresholds according to individual differences, enabling the system to have personalized adaptation capabilities and effectively overcoming the problem of inconsistent performance of the general model on different drivers.

[0025] S3. Continuously compare the fatigue index with the dynamically adjusted physiological threshold. When the fatigue index exceeds the physiological threshold and remains at the preset duration, generate the first intervention trigger condition. Furthermore, the initial physiological threshold is set as... ; Introducing environmental correction factors The time of day is determined based on the time of vehicle startup: if the startup time is at night, then... ,otherwise =0; Introducing behavioral feedback correction factors The system records the past After the intervention, if the driver stops to rest within 5 minutes, and the number of times they do not rest exceeds 50%, then... ,otherwise =0; Dynamically update physiological thresholds for: ; The system continuously monitors the fatigue index. If continuous Each sampling period satisfies > If the condition for continuous over-limit is met, the first intervention trigger condition is generated. It should be noted that by introducing environmental time factors and historical behavior feedback factors to dynamically adjust the physiological threshold, the intervention triggering conditions can adapt to the driving risk level and user response habits, automatically increasing sensitivity in high-risk scenarios such as nighttime or frequent ignoring of warnings, thereby achieving intelligent prediction and on-demand intervention, avoiding missed or false alarms caused by fixed thresholds.

[0026] S4. Combining the user-preset intervention mode, vehicle continuous running time and manual trigger command, determine whether to generate a second intervention trigger condition or a third intervention trigger condition, and output an intervention enable signal based on the logical relationship between the first intervention trigger condition, the second intervention trigger condition and the third intervention trigger condition. Furthermore, the system reads the intervention mode identifier set by the user via the serial port touchscreen display. Its value is , or ; like Then the vehicle running timer will be started, and when the cumulative running time reaches the preset threshold... At that time, a second intervention trigger condition is generated; like Then, it continuously monitors the physical button signals on the headgear. When a valid pressing action is detected and the duration is greater than the de-shake threshold, a third intervention trigger condition is generated. like When either the first intervention trigger condition or the second intervention trigger condition is met, an intervention enable signal is output. Once a manual trigger command is detected, a third intervention trigger condition is immediately generated, and the intervention enable signal is forcibly set while the running timer is cleared. It should be noted that the settings , or Three intervention modes are provided, with manual trigger commands given the highest priority and timer reset function. This ensures the system's proactive protection capabilities in the absence of unconscious fatigue, while also fully respecting the driver's subjective wishes, preventing automated intervention from causing operational interference or psychological resistance, and improving the efficiency and acceptance of human-machine collaboration.

[0027] S5. After receiving the intervention enable signal, detect the contact impedance between the headgear electrode and the scalp. Only when the contact impedance is in the effective conduction range, output pulse width modulated electrical pulses to a specific area of ​​the head according to the stimulation intensity level set by the user. At the same time, accumulate the number of electrical stimulation triggers per unit time and implement upper limit locking. Furthermore, remeasure the current contact impedance. ; Set the effective conduction interval as ,like ≤ ≤ If so, the electrode contact is considered good; If there is poor contact, the electrical stimulation output will be prohibited, and a message indicating that the electrodes are not in contact will be displayed on the serial port screen. If the contact is good, the user-defined stimulation intensity level will be read. , The integers are 1 to 5, corresponding to five levels of constant output current; Drive boost circuit and The bridge outputs bipolar square wave pulses with a fixed frequency within a safe range and a preset duration for each stimulus. ; Meanwhile, the system maintains an hourly trigger counter. Before each successful electrical stimulation output, check If the condition is met, then the stimulus is applied and the action is taken. Otherwise, it will enter a locked state until it automatically resets at the start of the next hour; It should be noted that the electrode contact status is forcibly verified before the electrical stimulation is output. Combined with constant current control, single duration limit and hourly trigger limit lock mechanism, a closed-loop protection system is constructed from three dimensions: electrical safety, physiological tolerance and frequency of use. This ensures that the head electrical stimulation is always within a safe, controllable and compliant range, meeting the stringent requirements for personal safety of in-vehicle wearable devices.

[0028] S6. Transmit the intervention mode type, time count value, historical stimulation record and electrode contact status to the serial port touch screen through serial communication, and display them on the screen in real time for user interaction and configuration. Furthermore, the main control module packages the currently running data in a fixed frame format, including: Intervention mode identifier, remaining runtime, timestamps of the last five interventions, and current contact impedance value. Hourly trigger count And the lock flag; Data frames are sent to the serial touch display at a baud rate of 9600 via the UART interface. The display has an 800×480 resolution, capacitive touch function, and support for the Taojingchi scripting language. After receiving the data frame, the display parses each field and updates it in the preset UI page accordingly, including: The colors of the mode icon, countdown progress bar, time record in the list control, and status indicator light are as follows: green indicates good contact, and red indicates abnormality. When the user touches the intensity adjustment slider, the display generates... instruction; When the user clicks the mode switch button, generate instruction; After receiving the instruction, the main control module writes the new parameters into the internal 1024-byte EEPROM storage area and immediately applies them to the next intervention judgment and output process; It should be noted that by using a high-resolution serial touch screen to achieve visualized parameter configuration and real-time feedback on operating status, complex intervention logic is transformed into an intuitive graphical interface, effectively reducing the user's learning cost. At the same time, non-volatile storage enables parameter persistence, allowing the system to retain personalized settings after a power outage and restart, effectively improving the product's usability, reliability, and user experience consistency.

[0029] This embodiment also provides a fatigue driving intervention system based on head electrical stimulation, including: The system includes a physiological signal acquisition module, a fatigue index calculation module, a dynamic threshold determination module, a dual-mode intervention decision-making module, a safe electrical stimulation execution module, and a human-computer interaction display module. The physiological signal acquisition module is used to acquire the driver's scalp micro-movement frequency and scalp-electrode impedance changes in real time through a head-mounted sensing device, and generate raw physiological state signals. The fatigue index calculation module is used to calculate the current fatigue index, which represents the degree of fatigue and the degree of attention distraction, based on the original physiological state signals and in combination with preset benchmark values ​​and weighting coefficients. The dynamic threshold determination module is used to continuously compare the current fatigue index with the dynamic physiological thresholds of the integrated environmental time period factor and the user behavior feedback factor, and generate the first intervention trigger condition when the excessive duration condition is met. The dual-mode intervention decision module is used to output intervention enable signals according to preset priority logic based on the user-defined intervention mode, the vehicle's continuous running time, manual trigger commands, and the first intervention trigger conditions. The safe electrical stimulation execution module is used to detect the electrode contact status after receiving the intervention enable signal, output head electrical stimulation at the intensity set by the user only when the contact is effective, and lock the upper limit of the number of triggers per unit time. The human-computer interaction display module is used to receive user configuration parameters through a serial port touch screen and display the intervention mode, timing status, historical records and electrode contact status in real time, realizing two-way interaction and persistent parameter storage.

[0030] This embodiment also provides a computer device applicable to the fatigue driving intervention method based on head electrical stimulation, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement the fatigue driving intervention method based on head electrical stimulation as proposed in the above embodiment.

[0031] The computer device can be a terminal, comprising a processor, memory, communication interface, display screen, and input devices connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. The display screen can be an LCD screen or an e-ink screen. The input devices can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0032] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements the fatigue driving intervention method based on head electrical stimulation as proposed in the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0033] In summary, this invention constructs an individualized fatigue index model by integrating dual-dimensional physiological signals of scalp micro-motion frequency and impedance fluctuations. It also introduces a dual correction mechanism based on environmental time period and user behavior feedback to dynamically adjust the intervention threshold, effectively improving the accuracy and timeliness of fatigue identification. Furthermore, it employs a three-state intervention logic—active timing, passive manual, and hybrid collaborative—balancing automated early warning with user autonomy. Combined with a safe electrical stimulation execution architecture based on contact impedance detection, current intensity grading, and trigger count locking per unit time, it ensures the safety and compliance of head electrical stimulation in in-vehicle scenarios. Finally, it integrates a serial touchscreen for visualized parameter configuration and real-time status feedback, forming a closed-loop system. This effectively addresses the problems of high false alarm rates, delayed response, lack of safety guarantees, and insufficient human-machine collaboration in existing fatigue driving intervention technologies.

[0034] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A fatigue driving intervention method based on forehead electrical stimulation, characterized in that: include: The original physiological state signals are obtained by collecting EEG signals from the driver's forehead using a head-mounted sensing device. The current fatigue index is calculated based on the ratio of low-frequency to high-frequency components in the original physiological state signal. A decrease in the fatigue index corresponds to an increase in the degree of fatigue and an increase in attention distraction, respectively. The fatigue index is continuously compared with a dynamically adjusted physiological threshold. When the fatigue index exceeds the physiological threshold and remains at the preset duration, a first intervention trigger condition is generated. Based on the user's pre-set intervention mode, vehicle continuous running time, and manual trigger command, it determines whether the first, second, or third level intervention trigger conditions are met, and outputs an electrical pulse stimulation command signal of the corresponding intensity level according to the level of trigger conditions met. Upon receiving the intervention enable signal, the contact impedance between the head-mounted electrode and the forehead skin is detected. Only when the contact impedance is within the effective conduction range, a short pulse width modulated electrical pulse is output to the connection position between the head-mounted electrode and the forehead skin according to the stimulation intensity level set by the user. At the same time, the number of electrical stimulation triggers per unit time is accumulated and an upper limit is locked. The intervention and detection cycle is repeated. The intervention mode, intervention time and intensity, and fatigue index are transmitted to a mobile phone or vehicle Bluetooth system via Bluetooth to enable interaction with the user or management system. The intervention mode, intervention time and intensity data are stored in this device in real time, with a minimum of 24 hours of data stored to achieve a black box function. The stored data can be accessed externally via USB or Bluetooth.

2. The fatigue driving intervention method based on forehead electrical stimulation as described in claim 1, characterized in that: The specific steps for acquiring EEG signals from the driver's forehead using a head-mounted sensing device to obtain raw physiological state signals are as follows: After the driver puts on the smart head-mounted device with integrated flexible dry electrodes, the system starts the electroencephalogram (EEG) signal acquisition process; The acquired raw EEG signals were sequentially pre-amplified, band-pass filtered (0.5–55 Hz), and subjected to power frequency notch filtering to obtain purified time-domain EEG signals. The purified EEG signal was windowed and segmented, and a Fast Fourier Transform (FFT) was performed on each segment to obtain the power spectral density in the range of 1–55 Hz. Extracting the α band (8–12 Hz) and The average power values ​​for the bands (12–25 Hz) are denoted as follows: and ; Will and As a key feature of primitive physiological state signals.

3. The fatigue driving intervention method based on forehead electrical stimulation as described in claim 2, characterized in that: The specific steps for calculating the current fatigue index based on the original physiological state signals are as follows: Calculate the spectral ratio ; Set a baseline ratio for the conscious state. ; right Perform normalization mapping to obtain the fatigue index. The expression is: ； in, ∈[0, 100], the lower the value, the higher the degree of fatigue; The fatigue index The values ​​correspond to the following states: 90–100 indicates full consciousness; 80–90 indicates mild fatigue; 70–80 indicates moderate fatigue; 60–70 indicates deep fatigue; 40–60 indicates a tendency towards deep sleep; A score below 40 indicates a deep level of unconscious risk. The During the system initialization phase, the user configures the system via a serial port touchscreen or loads it using factory default values.

4. The fatigue driving intervention method based on forehead electrical stimulation as described in claim 3, characterized in that: The process involves continuously comparing the fatigue index with a dynamically adjusted physiological threshold. When the fatigue index falls below the physiological threshold and remains below it for a preset duration, a first intervention trigger condition is generated. The specific steps are as follows: Set the initial physiological threshold as ∈[75, 85]; Introducing environmental correction factors If the vehicle starts at night (22:00–6:00), then = > 0, otherwise α = 0; Introducing a behavioral feedback correction factor β: The system records whether the driver stopped to rest within 5 minutes after the past K interventions. If the percentage of times the driver did not rest exceeds 50%, then β = β_high > 0; otherwise, β = 0. Dynamically update physiological thresholds for: ； The system uses a sampling period Continuous monitoring of fatigue index If continuous Each cycle satisfies < If the condition is met, the continuous over-limit condition is determined, and the first intervention trigger condition is generated.

5. The fatigue driving intervention method based on head electrical stimulation as described in claim 4, characterized in that: The system combines the user-preset intervention mode, vehicle continuous running time, and manual trigger command to determine whether to generate a second or third intervention trigger condition, and outputs an intervention enable signal based on the logical relationship between the first, second, and third intervention trigger conditions. The specific steps are as follows: The system reads the intervention mode identifier Mode set by the user through the serial port touch screen, which takes the value ACTIVE, PASSIVE, or HYBRID. If Mode = ACTIVE, then start the vehicle running timer. When the cumulative continuous running time is ≥ Generate the second intervention trigger condition; If Mode = PASSIVE, then continuously monitor the physical button signals on the head-mounted device. When a valid press is detected and the duration is greater than the de-shake threshold, generate a third intervention trigger condition. If Mode = HYBRID, then when either the first intervention trigger condition or the second intervention trigger condition is met, an intervention enable signal is output; Once a manual trigger command is detected, the intervention enable signal is immediately set, and the run timer is cleared, giving it higher priority than other conditions.

6. The fatigue driving intervention method based on head electrical stimulation as described in claim 5, characterized in that: Upon receiving the intervention enable signal, the contact impedance between the head-mounted electrodes and the forehead skin is detected. Only when the contact impedance is within the effective conduction range is a pulse-width modulated electrical pulse output to a specific area of ​​the head, based on the stimulation intensity level set by the user. Simultaneously, the number of electrical stimulation triggers per unit time is accumulated and an upper limit is locked. The specific steps are as follows: An AC excitation voltage with constant amplitude and fixed frequency is applied to the electrodes. Measure the loop current Calculate contact resistance ; Set the effective conduction interval as ; like ≤ ≤ If the electrodes are properly fitted, electrical stimulation can be output. Otherwise, output will be disabled and a message indicating that the electrodes are not in contact will be displayed on the screen; If the fit is good, the user-defined stimulation intensity level will be read. ,in = 1 to 5, corresponding to 5 output current levels; The boost circuit and H-bridge output a bipolar square wave pulse with a fixed frequency. Duration of a single stimulus Second; System maintenance hourly trigger counter Check before each output < ; If true, then the stimulus is executed and ; Otherwise, it will enter a locked state until it automatically resets in the next hour.

7. The fatigue driving intervention method based on head electrical stimulation as described in claim 6, characterized in that: The steps for transmitting the intervention mode type, time count value, historical stimulation record, and electrode contact status to the serial port touch screen via serial communication and displaying them on the screen in real time for user interaction and configuration are as follows: The main control module packages the current running data in a fixed frame format, including the intervention mode identifier, vehicle continuous running time, timestamps of the last five interventions, current contact impedance, hourly trigger count, and locking flag. Send to the serial touch display at a baud rate of 9600 via the UART interface; The display parses the data and updates the UI, including: The mode icon displays a running time progress bar, an intervention record list, and a contact status indicator light. When the user interacts with the slider or button, a setlevel=L or setmode=MODE instruction is generated; After receiving the data, the master controller writes it to the internal EEPROM, and it immediately takes effect in the next intervention process; All intervention events, fatigue index, and mode switching logs are stored locally for ≥24 hours and can be exported via USB or Bluetooth to achieve a black box function.

8. A fatigue driving intervention system based on head electrical stimulation, based on the fatigue driving intervention method based on head electrical stimulation according to any one of claims 1 to 7, characterized in that: It includes a physiological signal acquisition module, a fatigue index calculation module, a dynamic threshold determination module, a dual-mode intervention decision module, a safe electrical stimulation execution module, and a human-computer interaction display module; The physiological signal acquisition module is used to acquire the electroencephalogram (EEG) signal of the driver's forehead area in real time through the flexible electrodes on the head-mounted sensing device. After amplification and filtering of the signal, it is digitally converted and the EEG signal is subjected to spectrum analysis within a set time window to extract the high-frequency EEG components related to the awake state and the low-frequency EEG components related to the relaxed or drowsy state, forming the original physiological state signal for fatigue assessment. The fatigue index calculation module is used to calculate a fatigue index reflecting the level of brain activity based on the power ratio relationship between the high-frequency EEG components and the low-frequency EEG components. The higher the fatigue index, the more alert the driver is, and the lower the fatigue index, the more severe the fatigue and the more distracted the driver is. The fatigue index is quantified into a value between zero and one hundred. The dynamic threshold determination module is used to continuously compare the current fatigue index with a dynamically adjusted physiological threshold. The physiological threshold is automatically corrected based on whether the vehicle starts at night and the driver's past response to intervention prompts. When the fatigue index is lower than the physiological threshold and continues to reach a preset duration, a first intervention trigger condition is generated. The dual-mode intervention decision module is used to determine whether to output an intervention enable signal according to the intervention mode pre-selected by the user, combined with the vehicle's continuous running time, manual trigger command, and the first intervention trigger condition, and according to the set priority logic. The safe electrical stimulation execution module is used to detect the contact impedance between the head-mounted electrodes and the forehead skin after receiving the intervention enable signal. Only when the impedance is within the effective conduction range, it outputs short-duration electrical pulse stimulation to the forehead area according to the intensity level set by the user. It also counts the number of electrical stimulation triggers per hour. Once the upper limit is reached, the output stops until the next hour is reset. The human-computer interaction display module is used to receive user settings for intervention mode and stimulation intensity through a touch screen connected via a serial port, and to display the current fatigue state, running time, recent intervention records, electrode contact status, and whether it is in a trigger-locked state in real time, thereby realizing two-way interactive functions of parameter configuration, status feedback, and persistent data storage.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the fatigue driving intervention method based on head electrical stimulation as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the fatigue driving intervention method based on head electrical stimulation as described in any one of claims 1 to 7.

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