RU2376159C1 - Telemetry system to control locomotive operator "be-awake" state - Google Patents

Abstract

FIELD: railroad transport.

SUBSTANCE: proposed system comprises set of remote sensors, communication unit, signal digital processing and control unit, unit to process outer signals and to communicate with locomotive computer system. Signal digital processing and control unit comprises two identical data digital processing units wired to exchange data, "awake" state acknowledgement button and comparison unit. Unit to process outer signals and to communicate with locomotive computer system comprises data primary processing unit.

EFFECT: higher reliability.

8 cl, 6 dwg

Description

The invention relates to the diagnosis of the psychophysiological state of a person in the process of professional activity and can be used in automatic control systems for the condition of railway vehicle drivers.

One of the most informative criteria for transitioning to a state of driver’s loss of health - falling asleep - is a change in the skin-galvanic reaction (RU 2107460, NEUROKOM, 03/27/1998; US 6167299, Galchenkov et al., NEUROCOM, 12/26/2000; EP 0925758B1, Galchenkov et al ., NEUROCOM, 01/14/2004). The device contains electrodes with their mounting means connected to the input device, means for suppressing impulse noise, means for isolating a signal in the phase band of the electrodermal activity, means for detecting pulses of the phase component, a registration unit.

The technical aspects of the implementation of the device in transport - ensuring stable telemetry and maintaining wakefulness without creating additional inconvenience to the driver - are given in the descriptions of telemetric systems for monitoring the wakefulness of the driver of a vehicle (RU 2200095, 08/09/2001; RU 2251156, 27.04.2005 - NEUROKOM). So, the system according to patent RU 2251156 includes a telemetry sensor, reception, signal processing and control units, an indication unit including an indication control unit, to the outputs of which an audible alarm unit and wake level indicators are connected.

The closest analogue of the patented system is the telemetric operator health monitoring system according to patent RU 2282543, NEUROKOM, 08.27.2006. The system comprises a radio-coupled receiver and two telemetry sensors, as well as a digital signal processing and control unit, coupled to an indication unit. Each sensor has electrodes to ensure electrical contact with the skin of the driver, connected to an analog-to-digital converter, the output of which is connected to a transmitter with an antenna. One of the sensors is designed to be mounted on the wrist, and the other on the driver’s finger. The transmitters of both telemetry sensors and the receiver are configured to transmit and receive individual signals from each of the telemetry sensors. The digital signal processing and control unit is configured to sum the signals from both sensors in real time and calculate, based on this information, the wakefulness level (UB) of the driver.

However, the analysis shows that the reliability of the system is insufficient when implementing a circuit with a single digital signal processing unit, since there may be situations when an undetectable dangerous system failure occurs as a result of improper operation of the digital signal processing unit. In other words, with a working system for measuring and telemetry receiving information from sensors, a failure in the digital signal processing and calculation of health indicators can lead to the absence of an alarm signal even if the driver falls asleep.

This is especially dramatic for rail transport, since the amount of damage in the event of railway disasters is very large.

The patented telemetry system for monitoring the wakefulness of a locomotive driver contains:

a set of 1 telemetric sensors for installation on the wrist and on the finger of the driver to record changes in the electrical resistance of the skin,

communication unit 2 for receiving radio signals from telemetric sensors 10, 12 and exchanging service information with these sensors, includes interconnected transceiver 22, signal control unit 23, light and sound indication unit 24,

unit 3 for digital signal processing and control and unit 4 for processing external signals and communication with a computer system of a locomotive connected via interfaces 25, 26, 31, 41 to said communication unit 2,

the digital signal processing and control unit 3 includes two identical digital information processing units 32 and 33, configured to exchange information (321), a wake confirmation button 34, a comparison unit 35, the output of which is connected to the output signal generating unit 36, which is the system output and the inputs of the comparison unit 35 are connected to the outputs of the digital information processing units 32 and 33, the inputs and one of the outputs (331) of which (32, 33) are connected to the interface 31 and the wake confirmation button 34,

the external signal processing and communication unit 4 of the locomotive computer system comprises a primary information processing unit 42 having a group of inputs 43 for connecting to the corresponding electric circuits of the locomotive, and a connector 44 for connecting to the internal interface of the locomotive.

The system may be characterized in that the telemetry sensor contains two electrodes 101, 102 for providing electrical contact with the skin of the driver’s hands, connected to the input of the analog-to-digital converter 103, the output of which is connected to the input of the transceiver 104 and the antenna.

The system can be characterized by the fact that one telemetric sensor is made in the form of a bracelet by the type of wristwatch, and the other is in the form of a ring, on the surface of which, facing the driver’s body, electrodes are placed.

The system can also be characterized by the fact that telemetric sensors are mounted in a glove and fastened with it.

The system can also be characterized by the fact that the digital information processing unit is capable of fixing electric current pulses in the frequency band of the phase component of electrodermal activity, analyzing the shape of each pulse in a sequence of pulses in the mentioned frequency band, and extracting RHC pulses based on the correspondence of their shape to the established criteria.

The system can also be characterized by the fact that the driver’s wakefulness control is carried out according to the parameters of the following pulses of the skin-galvanic reaction, while the digital information processing units 32 and 33 are configured to measure the time intervals between the moments of the appearance of the skin-galvanic reaction pulses and calculate the current value of the wakefulness level according to the formula

UB = 1.66 · (60-Dt) (%), with Dt <60; UB = 0 (%), at Dt> 60;

where UB - the current value of the level of wakefulness; Dt - time interval between the moments of the appearance of pulses of the skin-galvanic reaction, sec.

The system can be characterized, in addition, by the fact that the block 36 for generating the output signal is a digital signal to voltage converter sufficient to control the braking system of the locomotive.

The system can also be characterized by the fact that the digital information processing units 32 and 33 are interconnected by a two-way bus 321 for exchanging bytes of intermediate information obtained by combining bits of service information and a binary value of the UB level of wakefulness, with subsequent comparison with their own bytes of intermediate information, and generating error flag in case of byte mismatch.

The technical result of the present invention is to increase the reliability of the system by organizing parallel independent calculations of the level of wakefulness (UB) and the introduction of an additional scheme for comparing the results of these calculations. The organization of the exchange of intermediate and service information between independent units of digital signal processing and calculation of performance indicators makes it possible to determine the correct functioning of the device.

The invention is illustrated by drawings, where:

figure 1 shows a block diagram of a patented wakefulness control system of the driver;

figure 2 is a block diagram of a telemetry sensor;

figure 3 presents the algorithm for the functioning of the system as a whole;

figure 4 - algorithm for calculating the level of wakefulness;

figure 5 - layout decision blocks of the system;

figure 6 - the implementation of telemetric sensors.

The system comprises (FIGS. 1, 2) a set of 1 telemetric sensors for a locomotive driver, a communication unit 2 with telemetric sensors, a digital signal processing and control unit 3, an external signal processing and communication unit 4, and a communication with the computer locomotive system.

Kit 1 includes at least two telemetric sensors 10, 12. The sensors are designed to obtain information about the psychophysiological state of the vehicle driver and transmit this information over the air. The psychophysiological state is recorded by a change in skin resistance - a skin-galvanic reaction (RAG). Telemetric sensors 10, 12 are located on the wrist and on the finger of the driver. Sensors can be made in the form of a bracelet (or watch), a ring or placed in a glove.

A single telemetric sensor 10 (see figure 2) has electrodes 101, 102 for providing electrical contact with the skin of the driver’s hands, connected to the input of an analog-to-digital converter (ADC) 103, the output of which is connected to the input of the transceiver 104 with antenna 105. The sensor power carried out by a built-in removable stand-alone element (not shown). Telemetric sensors are characterized by an identical functional diagram and differ only in the shape of the housing and electrodes (see also Fig.6).

Communication unit 2 is intended for receiving high-frequency radio signals from telemetric sensors 10, 12, exchanging service information with these sensors and digital processing and control unit 3. Block 2 contains a transceiver 22 with an antenna. The transceiver 22, as well as a set of 1 sensors 10, 12, is performed in such a way as to ensure the receipt of telemetry information on the radio channel with subsequent separation of the signals. The output of block 22 is associated with the possibility of two-way exchange with block 23 of the signal control. One output of block 23 is connected to block 24 of light and sound indications. Another input-output unit 23 through the interface 25 is connected to the unit 3 of digital signal processing and control. The third input-output unit 23 through the interface 26 is connected to the unit 4 for processing external signals and communication with the computer system of the locomotive. Block 24 light and sound indication - display - is designed to display the level of wakefulness (UB) of the driver, to indicate the presence of radio signals from both sensors 10, 12, as well as to generate an alarm.

The principles and means of exchanging telemetric information - the choice of different frequencies of transmitters, various types of modulation, etc., which are implemented in the patented system, do not require presentation in this description, because they are known to a specialist (see, for example, http: // www .cdma.aaanet.ru / cdma8006.html). The telemetry system can be performed in accordance with the international standard IEEE.802.15.4. The transceiver can be performed, for example, according to the ZigBee protocol ( http://www.wireless.ru/wireless/1276 ). This protocol, with low energy resources of connected devices, provides a range of about 10 meters and a channel capacity of up to 250 kbit / s. Transmission at this speed is in the 2.4 GHz frequency range.

Block 3 of digital signal processing and control includes an interface 31 that connects it with block 2. Interface 31 is further connected with blocks 32 and 33 of digital information processing, which provide the calculation of UB. Blocks 32 and 33 are identical and can be performed, for example, using microcontrollers. The wake confirmation button 34 is connected to the inputs of blocks 32, 33, according to its purpose and function, which performs the role of the so-called so-called railway handles of vigilance.

Blocks 32 and 33 have a common digital bus 321 for mutual exchange of information. The output of one of the blocks 32 or 33 (bus 331 is shown in FIG. 1) is connected via an interface 31 to a block 2 for transmitting information to the indicator 24. Other outputs of the blocks 32 and 33 are connected to a comparison block 35 for analyzing the identity of the UB calculation results. The output of the comparison unit 35 is connected to the input of the output unit 36 of the output signal of the telemetry wake control system of the driver. Block 36 is a digital signal to voltage converter necessary for controlling the braking system of a locomotive. The output of block 36 is connected through the output terminals 37 to the corresponding control circuits of the locomotive.

Unit 4 for processing external signals and communication with the computer system of the locomotive contains an interface 41 connecting it to unit 2, a unit 42 for primary information processing, having a group of inputs 43 for connecting to the corresponding electric circuits of the locomotive, connector 44 for connecting to the internal interface of the locomotive. Interfaces 25 and 31 can be organized, for example, according to the IRPS 20 mA current loop standard, and interfaces 26 and 41 can be organized according to the CAN BUS standard.

The system operates as follows.

The telemetry sensor 10 is attached to the finger, and the sensor 12 is mounted on the driver’s wrist. Upon contact of the electrodes 101, 102 of the sensor 10 and similar electrodes of the sensor 12 with human skin, it is possible to measure the electrical resistance of the skin, characterizing the current psychophysiological state of the driver. In the sensor 10, through the ADC 103, the current value of the electrical resistance is converted to digital form. This signal from the output of the ADC 103 enters the transceiver 104 and the antenna 105. Completely similar processes are carried out in the sensor 12. Further, the signals of the sensors 10 and 12 are transmitted over the air to the communication unit 2, where the output of the transceiver 22 is fed to the input of the signal control unit 23.

At the request of digital signal processing and control unit 3, an information code is supplied via interface 25 to unit 2. In response from unit 2, signals corresponding to the measured current value of skin resistance are transmitted to units 32 and 33. Blocks 32 and 33 of digital information processing analyze the data received from block 2. Based on this analysis, taking into account the well-known criteria for assessing the state of wakefulness of a person by RAG, in blocks 32 and 33, the UE of the driver is calculated. In the calculation process, blocks 32 and 33 exchange intermediate as well as service information to control the correct functioning of the system. Such information includes: the presence of a signal in the radio channels, the battery level of the sensor power batteries, the presence of signals at the inputs 43 of block 4.

In accordance with the value of UB calculated in blocks 32, 33, block 3 through the interface 31 to block 2 gives an indication code corresponding to the current UB value. The UD indication command is transmitted from one of the units 32, 33 to the interface 31 via a digital bus 331. Having received an indication code from the unit 3, the unit 24 displays the UD value and, when it is critically reduced, turns on visual and / or audible alarms. The appearance of visual and / or audible alarms will require the driver to press the wake confirmation button 34. The signal from pressing the button 34 is transmitted through blocks 32 and 33 to the input of block 35.

If the driver pressed the button 34 or block 4 registered and transmitted via the interface 41 to block 2 a signal via any of the inputs 43, the entire system continues to work as before. In the event that the button 34 has not been pressed or from block 4 to block 2 no signal has been received confirming wakefulness, the comparison block 35 provides control signals to the output signal generating block 36. Since the output terminals 37 of block 36 are connected to the emergency braking system of the locomotive, this system is triggered.

If the on-board network of the locomotive uses the CAN BUS standard, the patented system can be connected to its internal interface via connector 44 of the external signal processing unit 4 and communication with the computer system of the locomotive. Accordingly, in this case, information about the current value of the driver’s UB, the connection of alarms, the fact that the driver has pressed the wake confirmation button 34, and information about the presence of signals at the inputs 43 of block 4 will be transmitted to the on-board network of the locomotive.

The system operation algorithm is shown in Figs. 3 and 4. When the power is turned on (step p. 50), the radio signals from the sensors 10, 12 are checked (p. 51). In the event that there is no signal from both sensors 10, 12, the system returns to the tracking cycle for the appearance of the signal from the sensors.

If there is at least one of the signals in block 24, the signal reception indication from the corresponding sensor is turned on (p. 52).

Next, from block 2 to the input of each of the blocks 32, 33 information is transmitted about the current value of skin resistance (p. 53), service information (p. 54).

Blocks 32, 33 are the calculation of UB (p. 55) and converting it into binary code. At the same time, the value “32”, which corresponds to the driver’s full working capacity (professional activity), is taken as one hundred percent UB, and the value “0” is the UB corresponding to the state of falling asleep. The telemetry signal processing algorithm and the criteria for determining UB are known from the above patents (RU 2107460, US 6167299 and EP 0925758), are briefly described in the present description and are as follows (see FIG. 4).

Sensors 10 and 12 record changes in the electrical resistance of the skin of the driver, occurring in the frequency band of the phase component of electrodermal activity. The shape of each pulse in the sequence of pulses in the frequency band of the phase component is analyzed. To do this, in blocks 32, 33, the time derivative of the logarithm of the numerical value of the electric current is calculated (see §505, 551 in FIG. 4), the second time derivative of the logarithm of the numerical value of the electric current is calculated (§552). The magnitude of the trend is determined, due to changes in the signal in the frequency band of the tonic component of the electrodermal activity, and the magnitude of the first derivative is corrected by subtracting the magnitude of the trend from it (Section 553). The beginning of the pulse is determined by the moment the second derivative of the threshold value is exceeded (p. 544) and the moment of the end of the pulse (p. 555).

To determine the shape of the pulse, the maximum (f _MAX ) and minimum (f _MIN ) values of the first derivative are recorded minus the trend value, their ratio (r), the time interval (t _x ) between the minimum and maximum of the first derivative. In this case, the moments of reaching f _MAX and f _{MIN are} determined by the moment of changing the sign of the second derivative. The criteria for membership of the analyzed pulse to the signal of the phase component of electrodermal activity (RAG) (p. 566) may include the following inequalities:

0.5 <f _MAX <10; -2 <f _MIN <-0.1; 1.8 <t _x <7; 1.5 <r <10.

Next, determine the conformity of the pulse shape to the established criteria (p. 577). If there is such a correspondence, the analyzed pulse is referred to the RAG signals (p. 588), and in the absence of correspondence, it is referred to artifacts (p. 559).

The wakefulness level of the UB, for example, is calculated as a percentage by each of the blocks 32, 33 according to the value of the time intervals Dt (in seconds) between the moments of the appearance of the RAG pulses (Sec. 560) according to the formula

UB = 1.66 · (60-Dt) (%), with Dt <60; UB = 0 (%), at Dt> 60. (*)

All the numerical values of the criteria for determining the shape of the pulses and assigning them to the RAG signals and determining the UB are obtained on large statistical material (more than 10,000 measurements).

Using the received information, two bytes of intermediate information are generated (p. 56). Bytes are calculated by combining bits of overhead information and a binary value of UB calculated by blocks 32, 33. Then, bytes of intermediate information are exchanged on bus 321 between blocks 32 and 33 (p. 57). Received bytes are compared with their own bytes of intermediate information. In case of bytes mismatch, the block 32 and / or 33 generates an error sign (p. 58). If there are errors (p. 59), then an indication of their fact is made (p. 68).

The reasons for the formation of a sign of error

1. The absence of radio signals at the input of communication unit 2 with telemetric sensors.

2. If there are radio signals from the sensors 10, 12 - the absence of electrical contact of the electrodes 101, 102 with the skin of the driver’s hand, for example, when removing the sensors from the hand.

3. The presence of two or more working sets of sensors in the reception area of the radio signals by the communication unit 2.

At the same time, from the blocks 32, 33, the said test bytes are transmitted to the comparison block 35 (p. 60). In case of mismatch (p. 61) of the test bytes, the comparison unit 35 provides an error signal to the control action generating unit 36 at the terminals 37 (p. 67). If no errors are detected, the current UB value is displayed (p. 62).

Next, an analysis of the UB value is carried out (p. 63). The critical value of UB for an alarm is 10% according to the formula (*), i.e. in the described implementation, the value “3”. If the UB value is higher than critical, the system returns to step (p. 51). If the UB value is lower than critical, an alarm is issued (p. 64).

Then the driver’s response is checked: whether button 34 was pressed during the set time interval (p. 65). If button 34 is pressed, the system returns to step (p. 63). If button 34 is not pressed, the presence of signals from the locomotive controls (p. 66) from the group of inputs 43 is checked. If at least one of these signals is present, the system returns to step - p. 63. If there are no signals from the button 34 (p. 65) or the group of inputs 43 (p. 66), a control action (p. 67) is applied to the output terminals 37 connected to the braking system of the locomotive. After that, the system restarts (p. 69) and returns to step (p. 51).

Figure 5, 6 shows a photograph of one of the possible implementations of the system. A telemetry sensor 80 is designed for the driver’s wrist and contains a bracelet 801, like a wristwatch, to which a sensitive sensor unit 802 of a telemetry sensor is connected. On the inner surface of the node 802, two electrodes 803 are placed for contact with the skin of the driver when put on the arm. The elements of the radio circuit (ADC, transceiver and antenna) are housed in the housing 804. A similar embodiment has a ring 81 consisting of a bar - a spring ring 811, a sensing assembly 812, electrodes 813 on the inner surface of the ring and the housing 814 for accommodating the elements of the radio circuit. A power source (not shown) is housed in sensor housings.

The main blocks of the system are arranged in the form of separate nodes: pos. 82 - communication unit, pos. 83 - digital signal processing and control unit, pos. 84 - external signal processing and communication unit with a computer locomotive system. Pos. 821 shows the UB indicator in the form of a line of LEDs, pos. 822 - wake confirmation button, pos. 823 - audible alarm.

Claims (8)

1. A telemetry system for monitoring the wakefulness of a locomotive driver, containing a set of telemetric sensors for installation on the wrist and on the finger of the driver for recording changes in electrical resistance of the skin, a communication unit for receiving radio signals from telemetry sensors and exchanging service information with these sensors, including a transceiver connected to each other, a signal control unit, a light and sound indication unit, a digital signal processing and control unit and an external signal processing unit, and connected with the computer system of the locomotive, connected via interfaces with the said communication unit, the digital signal processing and control unit includes two identical digital information processing units configured to exchange information, a wake confirmation button, a comparison unit, the output of which is connected to the output signal generating unit which is the output of the system, and the inputs of the comparison unit are connected to the outputs of the digital information processing units, the inputs and one of the outputs of which are connected to the interface the som and the wake confirmation button, the external signal processing unit and the communication with the computer system of the locomotive contains a primary information processing unit having a group of inputs for connecting to the corresponding electric circuits of the locomotive and a connector for connecting to the internal interface of the locomotive. 2. The system according to claim 1, in which the telemetry sensor contains two electrodes for providing electrical contact with the skin of the driver’s hands, connected to the input of an analog-to-digital converter, the output of which is connected to the input of the transceiver and antenna. 3. The system according to claim 1, in which one telemetry sensor is made in the form of a bracelet by the type of watch, and the other is in the form of a ring, on the surface of which, facing the driver’s body, electrodes are placed. 4. The system according to claim 1, in which the telemetry sensors are installed in a glove and fastened with it. 5. The system according to claim 1, in which the digital information processing unit is configured to fix electric current pulses in the frequency band of the phase component of the electrodermal activity, analyze the shape of each pulse in the pulse sequence in the mentioned frequency band, select pulses of the galvanic-skin reaction based on the correspondence their forms to established criteria. 6. The system according to claim 1, in which the driver’s wakefulness control is carried out according to the parameters of the pulses of the skin-galvanic reaction, while the digital information processing units are configured to measure the time intervals between the moments of the appearance of the skin-galvanic reaction pulses and calculate the current value of the level of wakefulness according to the formula
UB = 1.66 · (6.0-Dt) (%) at Dt <60; UB = 0 (%) at Dt>60;
where UB - the current value of the level of wakefulness; Dt is the time interval between the moments of the appearance of pulses of the skin-galvanic reaction, s. 7. The system of claim 1, wherein the output signal generating unit is a digital signal to voltage converter sufficient to control the locomotive braking system. 8. The system according to claim 1, in which the digital information processing units are interconnected by a two-way bus for exchanging bytes of intermediate information obtained by combining bits of service information and a binary value of UB, followed by comparison with their own bytes of intermediate information and the formation of an error indicator in case of mismatch bytes.

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