A Digital Twin Platform for Testing the Outdoor Light Environment of Tunnels Considering Sky Element Scattering

Abstract

The present invention discloses a digital twin platform for testing the external light environment of a tunnel considering sky element scattering. The platform includes a twin body and a test device. The test device includes a spherical truss, and a lighting module composed of multiple light source monomers is arranged inside the spherical truss to simulate the sky scattering light environment; a sun simulation lamp is arranged on the annular lamp track to simulate sunlight; the left and right ends of the annular lamp track are hinged to the side wall of the spherical truss, and a platform is arranged inside the annular lamp track; a multi-dimensional rotation operation platform is arranged at the rotation center of the platform; a tunnel entrance model and an external scenery curtain are arranged on the rotation operation platform; photosensitive detection elements are evenly distributed on the multi-dimensional rotation operation platform and the external scenery curtain. The device of the present invention can simulate and master the spatio-temporal variation characteristics of the external light environment of the tunnel under different geographical locations, weather conditions, and compositions of the entrance scenery.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel lighting, and particularly relates to a digital twin platform for testing the external light environment of a tunnel considering sky element scattering. Technical Background

[0002] The external light environment of a tunnel mainly refers to the external brightness of the tunnel, which is an important basis for the design of the pavement brightness inside the tunnel and has a very important impact on the driving safety and lighting energy consumption of the tunnel section. The external brightness of a tunnel refers to the average brightness of the scenery within a 20° field of view at a distance of one stopping sight distance in front of the tunnel entrance for the driver. Among them, reflective scenery mainly includes the road surface, vegetation, and walls, and these sceneries generate brightness by reflecting direct sunlight and sky element scattered light; scattering scenery is mainly the sky, and its scattered light directly enters the human eye to generate brightness. The brightness of scattering scenery is mainly affected by the position of the sun and the weather, and the brightness of reflective scenery is mainly affected by the surface reflection characteristics and the incident angle of light. The brightness and color temperature of the external light environment of a tunnel have a great impact on the driver's recognition ability and driving comfort, and the accident rate at the tunnel entrance section is significantly higher than that of the tunnel interior section. However, the external brightness of the tunnel and lighting facilities are usually designed before the tunnel is built, and there is a large difference from the actual light environment at the tunnel entrance. Therefore, mastering the real situation of the external light environment of the tunnel is of great significance for the driving safety and lighting design of the tunnel section.

[0003] As an important indicator reflecting the external light environment of a tunnel, the external brightness of the tunnel is one of the design reference parameters of the tunnel lighting system. At present, the measurement methods of the external brightness of the tunnel include the look-up table method, the blackness method / digital camera method, and the environmental sketch method, and the relevant measurement platforms for the external brightness of the tunnel are also constructed based on these three methods.

[0004] Most of the existing methods for measuring the outdoor brightness of highway tunnels use general specifications to calibrate the brightness parameters of the scenery. The recommended values for the outdoor scenery brightness in the specifications are basically based on the regulations in the CIE and EU tunnel lighting standards, without considering the influence differences in different regions of China. This results in poor applicability and difficulty in meeting the actual engineering measurement requirements in China. The test conditions of the conventional on-site measurement methods are strictly limited. Usually, it is necessary to test under the condition of a strictly cloudless sky in summer. The test results are poorly repeatable due to outdoor climate factors such as the cloud shape, cloud amount, wind, and rain in the sky, and the parameter calibration is complex, and the measured outdoor brightness lags. Application No.: CN201220061294.5 discloses a device for simulating the sun's trajectory. This device can only demonstrate the sun's trajectory and cannot obtain the surface brightness of the scenery considering sky scattering synchronously. Application No.: CN201711382994.8 discloses a device for simulating the sky brightness distribution. This device can only simulate the sky brightness of a standard sunny day and a cloudy day and cannot simulate the sky scattering situation with any cloud amount. Application No.: CN201821117501.8 discloses an automatic simulation of the celestial dome. This device can only observe the shadow situation formed after the external light is blocked by the building and cannot comprehensively detect the surface brightness of the scenery. Summary of the Invention

[0005] In order to obtain the spatio-temporal variation characteristics of the outdoor brightness of the tunnel, the present invention provides a digital twin platform for testing the outdoor light environment of the tunnel considering sky element scattering to solve the problems mentioned in the background technology.

[0006] The technical solution of the present invention is as follows:

[0007] A digital twin platform for testing the light environment outside a tunnel considering sky element scattering, comprising a twin body and a test device; the twin body includes a data terminal and a light environment simulation model construction system; the light environment simulation model construction system is used to establish a tunnel light environment simulation model according to the tunnel space information parameters output by the test device (including the composition types of scenery such as end walls, road surfaces, tunnel openings, side walls, and the sky, and the proportion of the area of each scenery in a 20° field of view) and material optical parameters (the time-series change parameter table of the reflection coefficients of each scenery on the tunnel ground outside the tunnel at an observation angle of 0-10° and the time-series brightness of the sky); the data terminal is used to analyze and generate control data according to the tunnel light environment simulation model and the light intensity signal in the test device, and send the control data to the test device, so as to further control the color temperature and brightness of the lighting fixtures in the test device: specifically, a lighting control module can be set in the test device, and the data terminal sends the analyzed and generated control data to the lighting control module, and the lighting control module can further control the color temperature and brightness of the lighting fixtures in the tunnel of the test device; the test device includes a spherical truss, an annular light rail, a lighting module, a platform, a multi-dimensional rotation operation platform, a diffusion film, a light shield, a tunnel opening model, an outdoor scenery curtain, a slope lifting device, and a photosensitive detection element; the spherical truss is obtained by combining a plurality of polygonal unit structures, the polygonal unit structure includes a plurality of triangles and rhombuses, each polygonal unit structure is composed of a plurality of pipes, one side of the pipe facing the center of the polygonal unit structure is open, a diffusion film and light shields with different light transmittances are installed inside the polygonal unit structure, and after setting the light transmittance, the diffusion film and the light shield with the corresponding light transmittance will extend out through the pipe opening, and this process can be powered by a power supply system. The entire operation platform is covered by a hemispherical light shield and diffusion film.

[0008] In the above technical solution, further, a lighting module composed of a plurality of light source monomers is arranged on the inner spherical surface of the spherical truss for simulating sky scattering.

[0009] Further, an annular light rail is arranged inside the spherical truss, and a sun simulation lamp fixed at the top of the light rail and pointing to the center of the spherical truss is arranged on the annular light rail for simulating direct sunlight. The test device adjusts the color temperature and brightness of the lighting module and the sun simulation lamp according to the control data generated by the data terminal.

[0010] Further, the left and right ends of the annular light rail are hinged to the side wall of the spherical truss, and a platform is arranged inside the annular light rail. The bottom of the platform is fixed to the spherical truss and can move up and down relative to the spherical truss; a power driving device for providing power for its up and down movement is installed at the bottom of the platform.

[0011] Furthermore, a multi-dimensional rotating operation platform is arranged at the center of the platform, and the center point of the multi-dimensional rotating operation platform coincides with the center of the spherical truss.

[0012] Furthermore, a tunnel entrance model and an out-of-tunnel scenery curtain are arranged on the multi-dimensional rotating operation platform. The tunnel entrance model includes a slope lifting device, and the tunnel entrance model can mobilize the corresponding out-of-tunnel scenery curtain; photosensitive detection elements for collecting light intensity signals are evenly distributed on the multi-dimensional rotating operation platform and the out-of-tunnel scenery curtain.

[0013] The beneficial effects of the present invention are as follows: By controlling the synchronous change of the sun simulation lamp, the lighting module and the background sky light field information, the present invention realizes the accurate simulation of various types of sky brightness / color temperature distributions. The entire operation platform will be covered by a hemispherical light-shielding plate and a diffusion film, and the lighting module is directly arranged behind the diffusion film, avoiding the disadvantages of uneven light source brightness distribution and insufficient brightness due to long projection distance; at the same time, light-shielding plates with different light transmittances are set, and the initial light transmittance of the light-shielding plate is set as sunny. By loading light-shielding plates with specific light transmittances at designated positions, different cloud cover sky conditions can be simulated, solving the technical problem that random cloud cover sky cannot be simulated. In addition, the multi-dimensional rotating operation platform of the present invention can simulate the tunnel entrance orientation, can start the slope lifting device to simulate the tunnel slope, and unfold the designated out-of-tunnel scenery curtain to simulate the out-of-tunnel scenery characteristics of the tunnel. The out-of-tunnel scenery characteristics include plant mountains, etc., imitating mountain tunnels with different sky vision ratios; through the feedback data of the photosensitive detection elements, the synchronous measurement of each light environment parameter under different working conditions can be realized. A comprehensive real-time or quasi-real-time mapping relationship can be established between the physical space layer and the simulation space layer in the digital twin calculation model provided by the present invention, and two-way data information flow can be realized through the information control layer. In addition, the test device can output data to the twin body; the light environment simulation model construction system of the twin body can establish a tunnel light environment simulation model according to the tunnel space information parameters and material optical parameters of the test device; the data terminal of the twin body can analyze and generate regulation data by using the tunnel light environment simulation model and the light intensity signal in the test device, and send the regulation data to the test device, and further actions and interventions can be taken on the test device. Description of the Drawings

[0014] Figure 1 It is a schematic structural diagram of the test platform of the present invention;

[0015] Among them, 1 is a spherical truss, 2 is a polygonal unit structure, 3 is a sun simulation lamp, 4 is a multi-dimensional rotating operation platform, 5 is a platform, 6 is an annular light rail, 7 is an out-of-tunnel scenery curtain, and 8 is a tunnel entrance model. Detailed Embodiments

[0016] The following is combined with the attached Figure 1Further explanation of the method and device of the present invention and their beneficial effects.

[0017] Calculate the standard time. If daylight saving time is used for timing, one hour needs to be subtracted from the local time t local to obtain the standard time t s , which is calculated by Equation (1):

[0018] t s = t local - 1 (1)

[0019] In the formula, t s is the local standard time, h; t local is the local time, h;

[0020] Calculate the correction time. Considering the elliptical orbit of the Earth around the sun and the inclination of the Earth's axis relative to the orbital plane, the time error is adjusted to -14 to +16 min, and the correction time (ET) is obtained through Equation (2):

[0021]

[0022] In the formula, ET is the correction time, and the unit is decimal hours (for example, 13:30 = 13.5); J is the Gregorian calendar time, representing the serial number of the calculated date in a year;

[0023] Calculate the correction longitude. The correction longitude refers to the longitude of the calculation location relative to the standard meridian of the time zone (its central longitude). The time zone is nominally 15° wide. Therefore, compared with the standard meridian, the solar noon is about half an hour earlier and later at the eastern and western time zone boundaries respectively. If the longitude is at other positions in the middle of the time zone, corresponding corrections should be made according to the longitude position.

[0024] Calculate the solar time. The solar time can be calculated by Equation (3):

[0025]

[0026] In the formula, t is the solar time in decimal hours; t s is the local standard time in decimal hours; ET is the correction time in decimal hours; SM is the standard meridian of the time zone in radians; L is the longitude of the calculation location in radians;

[0027] Calculate the solar declination. After the solar time is determined, the solar altitude angle and azimuth angle can be calculated by calculating the solar declination. Among them, the solar declination can be calculated by Equation (4):

[0028]

[0029] Where δ is the solar declination in radians; J is the serial number of the calculated date in a year;

[0030] Calculate the solar position. The solar altitude angle and azimuth angle are calculated through Equations (5) and (6).

[0031]

[0032] Where a t is the solar altitude angle in degrees; l is the latitude of the calculation point in radians; δ is the solar declination in radians; t is the solar time in decimal hours;

[0033]

[0034] Where a s is the solar azimuth angle in radians; δ is the solar declination in radians; l is the latitude of the calculation point in radians; t is the solar time in decimal hours;

[0035] After calculating the solar position at each moment, run the solar simulation lamp 3 to the corresponding position and adjust the illuminance of the solar simulation lamp 3 to one ten-thousandth of the actual solar illuminance.

[0036] Calculate the illuminance E ij of a sky element with luminous brightness L ij at a certain point P on the surface of the scene, and the solid angle between this sky element and point P is dωdθ, and the relationship between E ij and L ij is shown in Equation (7).

[0037]

[0038] Where I ij is the luminous intensity of this sky element, r is the distance from this sky element to the calculation point P, θ is the altitude angle in the longitude direction, and ω is the altitude angle in the latitude direction.

[0039] The sky illuminance E P1 of the calculation point P is the sum of the illuminances of i×j luminous surface elements in the two-dimensional arc surface of the sky within the observation range of point P, as shown in Equation (8).

[0040]

[0041] Where the calculation of the luminous brightness L ij is as shown in the following formula:

[0042]

[0043] Where L a is the brightness of the calculation point, L zis the zenith luminance, χ is the shortest angular distance between the calculation point and the sun, Z is the zenith angle distance between the calculation point and the sun, and Z S is the zenith angle distance between the sun and the zenith, and a, b, c, d, e are parameters in the standard 15 sky types.

[0044] The zenith luminance L z The calculation formula is as follows:

[0045]

[0046] In the formula, γ S is the solar altitude angle, and the values of the coefficients a0, a1, a2, a3, a4, a5 vary according to the value of the clear sky index.

[0047] Turn on all the LED lights on the spherical truss 1 composed of the polygonal unit structure 2, and set the lighting power of each LED light according to the relative position of each sky element.

[0048] Place the tunnel entrance model 8 on the multi-dimensional rotating operation table 4. The multi-dimensional rotating operation table 4 rotates horizontally to simulate the orientation of the tunnel entrance, start the slope lifting device to simulate the tunnel slope, and unfold the outdoor scenery curtain 7 to simulate the characteristics of the outdoor scenery of the tunnel.

[0049] Turn on the lighting module and the sun simulation lamp 3, and open the diffusion film and the light-shielding plates with different light transmittances to simulate the change of sky cloud cover. Input the time-varying parameters to start the driving stepping motor to drive the circular lamp track 6 to rotate to the required position inside the spherical truss 1 and lock it.

[0050] Control the up and down movement of the control platform 5, control the rotational movement of the multi-dimensional rotating operation platform 4, and thus realize the simulation of different regions, different seasons, different actual locations and light intensities, etc., and measure the outdoor light environment of the tunnel through the photosensitive detection module. The time-varying parameters include the time of day, the time of year, the geographical location of the system and the weather conditions at the system location, etc.

[0051] Output data from the test device to the twin. The twin uses the tunnel space information parameters and material optical parameters to establish a simulated tunnel light environment simulation model.

[0052] The twin feeds back information to the test device. The photosensitive detection element is used to receive the external light and form a light intensity signal to transmit to the twin; and according to the information fed back by the twin, further actions and interventions are taken on the main body. Send the control data generated by the twin analysis to the lighting control module of the test device, and the lighting control module is used to control the color temperature and brightness of the lighting module and the sun simulation lamp 3 in the tunnel.

[0053] The specific embodiments of the present invention disclosed above are only examples, but the present invention is not limited thereto. Those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Obviously, these modifications and variations should fall within the scope of protection required by the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not impose any special limitation on the present invention.

Claims

1. A digital twin platform for testing the outdoor light environment of a tunnel considering sky element scattering, characterized in that: It includes twins and a test device; The twins include a data terminal and a light environment simulation model construction system; the light environment simulation model construction system is used to establish a tunnel light environment simulation model according to the tunnel space information parameters and material optical parameters output by the test device; the data terminal is used to analyze and generate control data according to the tunnel light environment simulation model and the light intensity signal in the test device, and send the control data to the test device, so as to further control the color temperature and brightness of the lighting fixtures in the test device; The test device includes a spherical truss (1), which is obtained by combining a number of polygonal unit structures. The polygonal unit structure includes a number of triangles and rhombuses. Each polygonal unit structure is composed of a number of pipes. One side of the pipe facing the center of the polygonal unit structure is open. A diffusion film and light-shielding plates with different light transmittances are installed inside the polygonal unit structure. After setting the light transmittance, the diffusion film and the light-shielding plates with corresponding light transmittances will extend out through the pipe openings; an illumination module composed of a number of light source monomers is provided on the inner spherical surface of the spherical truss (1) for simulating sky scattering; a circular lamp track (6) is provided inside the spherical truss (1), and a sun simulation lamp (3) fixed at the top of the lamp track and pointing to the center of the sphere of the spherical truss (1) is provided on the circular lamp track (6) for simulating direct sunlight; the test device adjusts the color temperature and brightness of the illumination module and the sun simulation lamp (3) according to the control data generated by the data terminal; the left and right ends of the circular lamp track (6) are hinged to the side wall of the spherical truss (1). A platform (5) is provided inside the circular lamp track (6). The bottom of the platform (5) is fixed to the spherical truss (1) and can move up and down relative to the spherical truss (1); a multi-dimensional rotation operation platform (4) is provided on the platform (5), and the center point of the multi-dimensional rotation operation platform (4) coincides with the center of the sphere of the spherical truss (1); a tunnel entrance model (8) and an out-of-tunnel scenery curtain (7) are provided on the multi-dimensional rotation operation platform (4). The tunnel entrance model (8) includes a slope lifting device, and the tunnel entrance model (8) can mobilize the corresponding out-of-tunnel scenery curtain (7); photosensitive detection elements for collecting light intensity signals are evenly distributed on the multi-dimensional rotation operation platform (4) and the out-of-tunnel scenery curtain (7).

2. The digital twin platform for testing the outdoor light environment of a tunnel considering the scattering of sky elements according to claim 1, characterized in that The circular lamp track (6) is circular, and its center coincides with the center of the sphere of the spherical truss (1); the circular lamp track (6) is movably hinged to the spherical truss (1) and can freely rotate around the hinge in the vertical plane. The circular lamp track (6) can move below the horizontal plane where the platform (5) is located.

3. The digital twin platform for testing the light environment outside the tunnel considering the scattering of sky elements according to claim 1 or 2, characterized in that Its working method is as follows: First, control the horizontal rotation of the multi-dimensional rotation operation platform (4) to simulate the orientation of the tunnel entrance, start the slope lifting device to simulate the tunnel slope, and unfold the out-of-tunnel scenery curtain (7) to simulate the out-of-tunnel scenery characteristics of the tunnel; Then, when detecting the brightness outside the tunnel, turn on the lighting module and the sun simulation lamp (3), and open the light-shielding plate and the diffusion film. Simulate the change of sky cloud cover by replacing the light-shielding plates with different light transmittances; input the time-varying parameters to start the driving stepping motor to drive the annular lamp rail (6) to rotate to a specific position and lock it. At the same time, start the platform (5) to move it to the required position, so as to realize the simulation of different regions, different seasons, different actual locations and light intensities, and measure the light environment outside the tunnel through the photosensitive detection element; wherein, the time-varying parameters include the time of day, the time of year, the geographical location of the system and the weather conditions at the system location.

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