RU2571891C1 - Device for operator's attention control in man-machine systems - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: device comprises series assemblies of electrodes, bioelectrical amplifiers, bioelectrical amplifier analysis and signalling; the electrode assembly comprises dry electrodes; the bioelectrical amplifier analysis assembly comprises first and second band-pass filters parallel connected to an output of bioelectrical amplifier assembly; an output of the first pass-band filter is parallel connected to a second-order peak-detector differentiating element and a three-threshold two-window amplitude discriminator; an output of the peak detector is connected through outputs of the first and second thresholds of the amplitude discriminator and first electronic key to drive inputs of first and second timers and to summing inputs of first and second counters; an output of the first timer and an output of the third threshold of the amplitude discriminator are connected to a blocking input of the first electronic key; an output of the second timer is connected to the second counter; outputs of the first and second counters are connected through the second and third electronic keys to outputs of the signalling assembly configured to supply 'alarm' and 'attention' sound signals. One output of the signalling assembly is connected to a sound generator, whereas a second output of the signalling assembly is connected to resetting inputs of the first and second ones; an output of the second pass-band filter is connected through an integrator and comparator to blocking inputs of the second and third electronic keys.EFFECT: accelerated identification and prevented incidental and non-conscious events of operator's impaired concentration.2 dwg

Description

FIELD OF THE INVENTION

The invention relates to medicine, in particular to medical equipment for diagnosing the psychophysiological state of a person, and can be used to improve the safety of vehicles and the safe functioning of “critical” technologies by maintaining a high level of attention, vigilance and efficiency of drivers of vehicles and special vehicles (drivers, pilots), as well as operators of “critical” technologies (dispatchers of transport and energy systems), d yours elf that is associated with an increased risk.

State of the art

Maintaining high efficiency, vigilance and error-free activity of operators in human-equipment systems is an extremely urgent task due to the fact that, according to statistics, from 30 to 80 percent of industrial accidents and catastrophes, traffic accidents occur due to the fault of the “human factor” . Moreover, the most common cause of such incidents is a decrease, distraction, or loss of attention of the operator in the process.

Today, technical devices for maintaining vigilance are known that periodically (every 15-90 seconds) give the operator (driver, driver) a test signal (visual or acoustic) to which the operator must quickly respond with a specific action (by pressing the button, turning the handle and etc.). In the absence of such a response, the device gives an alarm and / or automatically changes the parameters of a dynamic object (for example, turns on the braking mode) [Patent SU 1470585 (formula), 05/18/1987; Laser radar detector 268 RU "TopRadar" (company Whistler Group Inc., USA) with the Stay Alert function (Antison), 2011-2014]. The disadvantages of these devices are the relatively low speed (at least 20 seconds), that is, the impossibility of determining short-term (of the order of fractions or units of seconds) episodes of reducing the attention of a human operator to a “dangerous” level, as well as the creation of an additional information load on the operator, which distracts him from the main activity.

Another group of devices is also known for determining and maintaining vigilance, based on continuous registration (monitoring) and automatic measurement of various physiological parameters of a human operator directly in the process of activity. When the parameters of these indicators go beyond some experimentally determined limits, the operator is given a signal warning him of the onset of a “dangerous” functional state, and also (optionally) the parameters of the controlled dynamic object may change [see, for example, review 03 T024 Quintec 22 RPT Final Report Issue 01. 30th August 2002, Railway Safety, GB].

The accuracy, speed and noise immunity of these devices fundamentally depends on the nature of the recorded physiological parameters.

So, when using parameters of skin-galvanic reactions and / or electric skin resistance as an informative indicator [for example, patent RU 2025731 (formula), 12/30/1994; patent RU 2003541 (formula), 11/30/1993] to determine the occurrence of a "dangerous" functional state of the operator requires at least 15-60 seconds. Therefore, short-term (of the order of fractions or units of seconds) episodes of a decrease in the attention of a human operator by devices based on registration of electric skin indices are not determined. Moreover, the state of “fluctuating vigilance” of the operator is regarded by such devices as the state of active activity. In addition, the parameters of electrodermal activity vary significantly not only due to a change in the functional state of the operator, but also depending on external conditions (primarily temperature and humidity) and on the nature of the operator's activity (frequency and intensity of control actions).

When using as an informative indicator of the level of vigilance of the parameters of the oculomotor system (closing the eyes, blinking frequency, closing / opening speed of the eyelids, gaze direction and frequency of its switching) [Patent RU 2395228 (formula), 07/27/2010; patent RU 2423070 (formula), 07/10/2011; patent RU 2444275 (formula), 09/30/2010] significant limitations of such devices are: the operator wearing glasses (especially sun glasses), turning his head, changing his posture, vibration associated with the characteristics of the vehicle and the condition of the road surface. The speed of these devices (due to the temporal characteristics of the recorded indicators) also does not make it possible to determine short-term (in the order of fractions or units of seconds) episodes of reducing the attention of a human operator to a “dangerous” level.

A device is known for monitoring and controlling the functional state of an operator-pilot, based on the registration of the pilot’s squeezing effort of the aircraft’s control stick, changes in the trajectory of the control stick’s movement, the pilot’s foot rest on the pedals, head position, respiratory process, oxygen pressure and the quality of the mixture in the oxygen system , pressure in an anti-loading suit, current (taking into account critical) flight altitude, overload value. Moreover, the device contains sensors of physiological parameters of the state of the operator, connected to the measurement unit, the output of which is connected to the input of the analysis unit, which is associated with the information and command unit [patent RU 2150886 (formula), 06/20/2000]. The disadvantage of this device is the presence of a large number of different sensors that limit the movement and functionality of the operator.

The best time resolution among physiological indicators (from units to tens of milliseconds) is possessed by the parameters of the bioelectrical activity of the brain - electroencephalograms (EEG). It has been convincingly proved that the amplitude and frequency parameters of the EEG most reliably characterize the functional state of a person in the sleep-wake continuum, and some of them are directly related to visual attention. Until recently, the use of EEG as an informative indicator of the level of vigilance of a human operator in real-life conditions was difficult due to the low noise immunity of both recording equipment and traditional methods of EEG analysis.

A device is known for awakening a person to a fixed phase of sleep, based on recording the bioelectrical activity of the brain, determining sleep phases, empirically determining the phase of sleep, awakening in which is associated with the optimal psychophysiological state of subsequent wakefulness, exposure to an awakening signal in various phases of sleep. The awakening signal is synchronized with the electrical activity of the brain of the found sleep phase in a given time interval. The device includes a portable electroencephalograph with a rhythm analyzer, with the help of which a person’s EEG is recorded, and in particular during sleep, with simultaneous automatic analysis of EEG rhythms and determination of sleep phases, an electronic alarm clock that provides a pre-set time signal, usually sound, acting awakening way on a person [patent RU 2061406 (formula), 06/10/1996]. However, to register a psychophysiological signal, it is necessary to fix the discharge electrodes on the head of the person being examined, which cause inconvenience when using this device in practical professional activity, including those types for which the signaling about the functional state is of great importance. In addition, this device is designed to recognize only the stages of sleep, which limits its scope.

The closest analogue of the present invention is a device for diagnosing the functional state of a human operator according to the parameters of an electroencephalogram, containing a block of electrodes and a block of amplifiers connected in series, as well as an indicator, a block of correlators, a block of analog-to-digital converters, a memory block, a block of digital-to-analog converters and a calculation block difference modules connected in series, an adder, a first comparator, an integrator and a second comparator connected in series, and the mode switch, two reference voltage sources and a program unit, while the input of the latter is connected to the operation mode switch, and the output is connected to the inputs of the memory block, the outputs of the correlators are connected to the inputs of the difference module calculation unit, and the outputs of the latter are connected to the adder inputs, outputs the amplifier block is connected to the inputs of the correlator block, in addition, the inputs of the comparators are connected to the outputs of the corresponding voltage reference sources, and the output of the second comparator is connected to the indicator. This provides faster diagnostics and reliability of determining the functional state of a human operator [copyright certificate SU 1393398 (formula), 05/07/1988]. The disadvantages of this device are: the need to install a large number of electrodes (at least 4) on the operator’s head, the device is designed to distinguish only two functional states - rest and mental activity, and, in addition, the device requires settings (“training”) for parameters EEG of a specific operator.

SUMMARY OF THE INVENTION

The technical result of the proposed device is to accelerate the identification and prevention of involuntary and unconscious (including short-term) episodes of reducing the operator’s attention in the process of its activity due to the continuous recording of bioelectric indicators of its functional state and automatic analysis in real time (on-line) of their amplitude and frequency characteristics. In addition, the device does not limit the mobility and functionality of the operator.

This result is achieved by the fact that the device for monitoring the operator’s attention in human-technician systems, containing serially connected blocks: an electrode block, a biopotential amplifier block, a biopotential analysis block, and an alarm block, contains an electrode block in the form of active “dry” electrodes and the biopotential analysis block contains two band-pass filters PF1 and PF2 connected in parallel to the output of the digital biopotential amplifier, a second-order differentiator - “ peak detector ”(PD) and 3 threshold 2-window amplitude discriminator (HELL), PD output through electronic key 1, controlled by the outputs of the 1st and 2nd thresholds of the HELL, connected to the triggering inputs of two T1 timers and T2 and with the summing inputs of two counters Sch1 and Sch2, the output of timer T1 and the output of the 3rd threshold of blood pressure are connected to the blocking input of the electronic key 1, the output of timer T2 is connected to the counter Sch2, the outputs of the counters Sch1 and Sch2 through electronic keys 2 and 3 are connected with the inputs of the alarm unit, in which two types of sound signals are formed biofeedback communication - “alarm” and “warning”, one output of the alarm unit is connected to the sound emitter, and the second output of the alarm unit is connected to zeroing inputs of the counters Сч1 and Сч2, the output of the PF2 bandpass filter is connected to the integrator input, the output of which is connected to the comparator input, the comparator output connected to the blocking inputs of electronic keys 2 and 3.

Brief Description of the Drawings

In FIG. 1 is a simplified block diagram of a device; FIG. 2 is a detailed functional block diagram of a device.

Detailed Description of the Invention

A device for monitoring the operator’s attention in human-equipment systems consists of series-connected functional blocks: a biopotential recording unit (1), an electrode block (2) and a biopotential amplifier block (3), a biopotential analysis block (4), and an alarm unit ( 5), and is characterized in that:

1) in order to increase operator comfort in the biopotentials registration unit (1), active (“dry”) electrodes are used as a block of electrodes (sensors) (2);

2) in order to reduce time and improve identification accuracy and prevent episodes of lowering the operator’s attention level, increasing the noise immunity of the device and minimizing “false alarms”, the biopotential analysis unit contains two band pass filters PF1 (7) and PF2 (8), connected in parallel to the output of the amplifier unit biopotentials (3). A second-order differentiator — a “peak detector” of a PD (9) and a 3-threshold 2-window “amplitude” AD discriminator (10) are connected in parallel to the output of PF1 (7). The pulse output of the PD (9) is connected to the synchronizing input of the BP (10), and also through the outputs of the 1st (p1) and 2nd (p2) thresholds of the BP (10) and the outputs of the electronic key 1 (11) are connected to the triggering inputs of two timers T1 (12) and T2 (13) and with summing inputs (Σ) of two counters Сч1 (14) and Сч2 (15). The output of the timer T1 (12) and the output of the 3rd threshold (p3) of the blood pressure (10) are connected to the blocking input of the electronic key 1 (11). The output of the timer T2 (13) is connected to the input of the counter Сч2 (15), the outputs of the counters Сч1 (14) and Сч2 (15) are connected via electronic keys 2 (16) and 3 (17) to the inputs of the alarm unit (5). The output of the bandpass filter PF2 (8) is connected to the input of the integrator (18), the output of which is connected to the input of the comparator (19), the output of the comparator (19) is connected to the blocking inputs of the electronic keys 2 (16) and 3 (17), the outputs of the signaling unit ( 5) connected to the “zeroing” inputs (0) of the counters Сч1 (14) and Сч2 (15), as well as to a sound emitter (earphone) (6);

3) in order to maintain operator’s attention at an optimal level by informing him of the beginning of an episode of “dangerous” attention loss, urgently interrupting such episodes and warning the operator of a high probability of developing an episode of attention loss, two types of bi-feedback sound signals are generated at the output of the alarm block (5) communication - “alarm” (triggered by the SCh1 counter (14) through the electronic key 2 (16)), and “warning” (triggered by the SCh2 counter (15) through the electronic key 3 (17)), which come from the output of the alarm unit tion (5) to the sounder (earphone) (6).

The device operates as follows

The bioelectric activity recorded by the block of active “dry” electrodes (2) (two are enough) located on the head of the human operator is enhanced by the biopotential amplifiers block (3) located there and transmitted to the inputs of the band pass filters PF1 (7) and PF2 ( 8) a block of analysis of biopotentials (4). From the output of PF1 (7), the signal is fed to the input of the second-order differentiator — the “peak detector” of the PD (9) and to the input of the 3 threshold 2-window amplitude discriminator HELL (10). If at the instant of operation of the “peak detector” of the PD (9), the amplitude of the signal at the input of the BP (10) does not exceed the 1st amplitude threshold of the BP (p1 is the threshold of “noise”), then the output pulse from the PD (9) is blocked by an electronic key 1 (11) and further does not enter. If at the instant of the PD peak detector’s response time (9), the signal amplitude is in the “lower” amplitude BP window (10) (between the 1st and 2nd amplitude thresholds - between n1 and n2), the pulse from the PD output (9 ) through the electronic key 1 (11) it enters the summing input of the counter Сч2 (15), and also starts the timers T1 (12) and T2 (13). If at the instant of the PD peak detector’s response (9) the signal amplitude is in the “upper” amplitude window of the BP (10) (between the 2nd and 3rd amplitude thresholds - between n2 and n3), the pulse from the output of the AP ( 9) through the electronic key 1 (11) it enters the summing inputs of both counters Сч1 (14) and Сч2 (15), and also starts the timers T1 (12) and T2 (13). If at the instant of the PD peak detector’s response time (9), the signal amplitude exceeds the 3rd amplitude threshold of HELL (11) (the “interference” threshold is p3), the pulse from the PD output (9) is blocked by electronic key 1 (11) and does not go to the summing inputs of the counters Сч1 (14) and Сч2 (15) and to the timers Т1 (12) and Т2 (13). A similar blocking of the summing inputs of the counters Сч1 (14) and Сч2 (15) occurs if each next pulse from the PD output (9), corresponding to the amplitude of the signal from the PF1 (7) output falling within the limits of the “windows” of the BP (10), comes earlier or after a certain time delay (t) after the previous pulse from the PD output (9) (the boundaries of this time delay t1 and t2 are set by the timer T1 (12), which is triggered by each next pulse from the output of the PD (9)). Upon reaching the sum of the pulses in the counter Sch1 (14) of a certain “critical” number, the signal from its output through the electronic key 2 (16) is fed to the input of the alarm unit (5), where in this case an “alarm” sound signal of biofeedback is transmitted to a sound emitter (earphone) (6) on the operator’s head and informing him of the beginning of an episode of a “dangerous” decrease in the level of attention. The "speed" of identifying such a functional state using the proposed device is 0.25-0.5 s. When the sum of impulses in the counter Сч2 (15) reaches a certain “critical” number per unit time (set by the timer T2 (13)), the signal from its output through the electronic key 3 (17) is fed to the input of the alarm unit (5), where in this case a “warning” biofeedback audio signal is generated, which is transmitted to the sound emitter (earphone) (6) on the operator’s head and informs him of the high probability of an episode of decreased attention level in the near future (after 5-30 s). The output signal of the alarm unit (5), synchronous with the sound signals, is also fed to the “zeroing” inputs of the counters Сч1 (14) and Сч2 (15). In addition, if the signal level at the output of the integrator (18) exceeds the threshold of the comparator (19), then the output signal of the comparator (19) is fed to the blocking inputs of the electronic keys 2 (16) and 3 (17), while the sound signals from the alarm unit (5) the earphone (6) is not fed.

Structurally, the block of active “dry” electrodes (2), the block of biopotential amplifiers (3) and the sound emitter (earpiece) (6) are placed on the head of a human operator and are fixed in any headgear (for example, in a standard protective helmet, on a standard microtelephone headset, on a tennis ribbon or on a hair hoop). The output of the biopotential amplifiers block (3) with the input of the biopotential analysis block (4) and the output of the alarm block (5) with a sound emitter (earphone) (6) are connected via wireless (BlueTooth) communication. Functional blocks of the analysis of biopotentials (4) and signaling (5) are implemented on the basis of a microprocessor and combined in a single construct (with the dimensions of a smartphone).

The specific location of the sensor electrodes (2) on the operator’s head, the values of the boundaries of the frequency ranges of the band-pass filters PF1 (7) and PF2 (8) in Hz, the values of the 1st (p1), 2nd (p2) and 3rd (p3 ) the amplitude thresholds of the 2 “window” amplitude AD discriminator (10) in μV, the values of the boundaries of the time ranges of the timers T1 (12) (t1 and t2 in ms) and T2 (13) in seconds, the values of “critical” numbers in the counters Sch1 (14) and Sch2 (15) in units of time constants accumulation value and the "leakage" of the integrator (18) in seconds) and the threshold value comparator (19) in microvolts ^2, inf rmativnye to identify and prevent the onset of episodes of reducing the level of operator attention, the authors determined the application in a series of psychophysical experiments in the laboratory and bench (simulation) conditions, as well as in the tests performed under real professional activity of a human operator (driver of the car, pilot). It is also determined that the device does not require tuning to the individual bioelectric activity parameters of a particular operator.

Experiments and tests have shown high noise immunity (with respect to physical and physiological interference) of a special algorithm implemented by the device in the form of a combination of amplitude-interval analysis (period analysis) of biopotentials and the allocation of certain combinations of bioelectric activity, compared with traditionally used narrow-band filtering and Fourier transform, which is fundamentally important for reliable error-free operation of the device (including to minimize "false alarms") in real devices oviyah professional activity of a human operator.

In the future, the output signals of the device’s alarm unit can be used not only to control the level of attention of the operator, but also to change the parameters of a dynamic object controlled by the operator (for example, to reduce the speed of the vehicle or transfer it to automatic control), as well as to reorganize the group operators during their joint (team) work (for example, to automatically redistribute the amount of information received by each operator).

Thus, the proposed device provides high efficiency in the identification and prevention of involuntary and unconscious (including short-term) episodes of reducing operator attention in the process.

Using the device, several bioelectric indicators of its functional state are continuously recorded during the operator’s activity, their amplitude and frequency characteristics are automatically analyzed in real time (on-line) using a special algorithm, and the appearance of a specific combination of bioelectric activity indicators determines the beginning of an “dangerous” decline operator’s attention, as well as an audible “alarm” signal is sent to withdraw the operator from the “dangerous” functional standing and a "warning" sound signal to prevent the occurrence of episodes of a "dangerous" decrease in operator's attention.

The proposed device allows you to identify episodes of involuntary "dangerous" decrease in operator attention with a speed of less than 1 second, interrupt such episodes, and also prevent their occurrence.

The proposed device does not limit the mobility and functionality of the operator and can be used to maintain a high level of attention, vigilance and efficiency of drivers of vehicles and special vehicles (including pilots, drivers), as well as operators of "critical" technologies (for example, traffic dispatchers and energy systems).

Claims (1)

A device for monitoring the attention of a human operator in "human-equipment" systems, containing serially connected blocks of electrodes, biopotential amplifiers, biopotential analysis and signaling, characterized in that the electrode block contains active "dry" electrodes, the biopotential analysis block contains the first and second strip filters connected in parallel to the output of the biopotential amplifiers block, a second-order differentiator — a peak detector and 3 pores — are connected in parallel to the output of the first band-pass filter the second “window” amplitude discriminator, the peak detector output is connected via the outputs of the 1st and 2nd thresholds of the amplitude discriminator and the first electronic key to the triggering inputs of the first and second timers and to the summing inputs of the first and second counters, output the first timer and the output of the 3rd threshold of the amplitude discriminator are connected to the blocking input of the first electronic key, the output of the second timer is connected to the second counter, the outputs of the first and second counters are connected through the second and third electronic keys to the inputs and an alarm unit configured to provide “alarm” and “warning” sound signals, one output of the alarm unit is connected to the sound emitter, and the second output of the alarm unit is connected to zeroing inputs of the first and second, the output of the second bandpass filter is connected through an integrator and a comparator with blocking the inputs of the second and third electronic keys.

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