Tunnel vehicle-mounted illumination control method based on PCHIP interpolation method

Abstract

The invention discloses a tunnel vehicle-mounted illumination control method based on a PCHIP interpolation method. The tunnel vehicle-mounted illumination control method comprises the following steps: step 1, obtaining real-time outside-tunnel brightness, traffic flow and vehicle speed data of a tunnel; 2, calculating the minimum illumination demand value of each illumination section in the tunnel according to the data obtained in the step 1; wherein each lighting section comprises an entrance section, a transition section, a middle section and an exit section; step 3, selecting boundary points of each lighting section as interpolation points, and performing smooth fitting through a PCHIP interpolation method to obtain a fitting curve meeting the lowest lighting requirement of each lighting section; and step 4, obtaining the length of each lamp loop in the lighting sections of which the lamp loops can be subdivided, segmenting the fitting curve of the corresponding lighting section according to the length of each lamp loop, forming a segmented curve based on the tunnel lighting requirement of each lighting section lamp loop, and controlling the tunnel vehicle-mounted lighting according to the segmented curve. The method overcomes the defect that only the tunnel design traffic flow and the vehicle speed are considered to meet the tunnel lighting requirement.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel lighting control, and in particular to a tunnel vehicle lighting control method based on a PCHIP interpolation method. Background Art

[0002] Tunnel lighting is a key factor in ensuring road traffic safety. In recent years, energy conservation and emission reduction have been the main development direction. Energy conservation in tunnel lighting has become an irreversible trend and is ushering in unprecedented development opportunities. At present, most tunnel lighting systems mainly rely on increasing lighting brightness to improve the light level in the tunnel. Although this method improves driving safety to a certain extent, excessive brightness increases will undoubtedly lead to increased energy consumption. In the context of global energy conservation and emission reduction, how to optimize the calculation of tunnel lighting needs and reduce energy consumption while ensuring driving safety has become an urgent problem to be solved.

[0003] There are still many deficiencies in the demand calculation of tunnel lighting fixtures that need to be improved. For example, the demand calculation of lighting fixtures in tunnels at different times usually uses indicators such as design traffic volume and design speed to calculate, while ignoring the impact of changes in real-time traffic volume and speed on lighting demand; the lighting demand of each lighting section of the tunnel is usually a fixed value, and the lighting demand curve is segmented, without fully considering the transition of lighting demand between lighting sections, and without giving full play to the impact of the number of lighting fixture circuits in the tunnel lighting section on the division of lighting demand. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a tunnel vehicle lighting control method based on the PCHIP interpolation method to solve the technical problem of poor real-time performance of tunnel lighting control in the prior art.

[0005] The present invention provides a tunnel vehicle lighting control method based on PCHIP interpolation method, comprising the following steps:

[0006] Step 1: Obtain real-time tunnel brightness, traffic flow and speed data;

[0007] Step 2: Calculate the minimum lighting requirement value of each lighting section in the tunnel according to the data obtained in step 1; wherein each lighting section includes: an entrance section, a transition section, a middle section, and an exit section;

[0008] Step 3: Select the boundary points of each lighting segment as interpolation points, perform smooth fitting through the PCHIP interpolation method, and obtain a fitting curve that meets the minimum lighting requirements of each lighting segment;

[0009] Step 4: Obtain the length of each lamp circuit in the lighting segment that can subdivide the lamp circuit, segment the fitting curve of the corresponding lighting segment according to the length of each lamp circuit, form a segmented curve based on the tunnel lighting requirements of the lamp circuit of each lighting segment, and control the tunnel vehicle lighting according to the segmented curve.

[0010] Furthermore, in step 2, the calculation method of the minimum lighting requirement value of the entrance section is:

[0011] The entrance section is divided into two entrance lighting sections, and the calculation formulas are:

[0012] L th1 = k × L 20

[0013] L th2 =0.5×k×L 20

[0014] Where, L th1 is the minimum lighting requirement value of the first entrance lighting segment; L th2 is the minimum lighting requirement value of the second entrance lighting segment; k is the brightness reduction coefficient of the entrance segment; L 20 The brightness outside the cave.

[0015] Furthermore, in step 2, the calculation method of the minimum lighting requirement value of the transition section is:

[0016] The transition section is divided into three transition lighting sections according to the principle of gradual decrease, and the calculation formulas are:

[0017] L tr1 =0.15×L th1

[0018] L tr =0.05×L th1

[0019] L tr3 =0.02×L th1

[0020] Where, L th1 is the minimum lighting requirement value of the first entrance lighting segment; L tr1 L is the minimum lighting requirement value of the first transition lighting segment; tr2 is the minimum lighting requirement value of the second transition lighting segment; L rr3 It is the minimum lighting requirement value for the third transition lighting segment.

[0021] Furthermore, in step 2, the calculation method of the minimum lighting requirement value of the middle section is:

[0022] The traffic volume Q and vehicle speed V at different hours are calculated by interpolation method. The specific formula is as follows:

[0023]

[0024] Furthermore, in step 2, the calculation method of the minimum lighting requirement value of the exit section is:

[0025] The exit section is divided into two exit lighting sections, and the calculation formulas are:

[0026] L ex1 =3×L in

[0027] L ex2 =5×L in

[0028] Where, L in is the minimum lighting requirement value of the middle section; L ex1 is the minimum lighting requirement value of the first exit lighting segment; L ex2 It is the minimum lighting demand value of the first exit lighting segment.

[0029] Furthermore, the specific formula of the brightness reduction coefficient is:

[0030]

[0031] Where Q is the traffic volume at different hours; V is the vehicle speed.

[0032] Furthermore, in step 3, the method for setting the interpolation points includes:

[0033] Selection of interpolation points for non-middle sections of tunnels and selection of interpolation points for middle sections of tunnels,

[0034] Among them, the method for selecting interpolation points in the non-middle section of the tunnel is:

[0035] Select the starting and ending points of the entire tunnel as two interpolation points; select the brightness points at the end of the entrance section and the transition section as the interpolation points of the corresponding sections; select the brightness point at the starting point of the exit section as the interpolation point of the exit section;

[0036] The method for selecting interpolation points in the middle section of the tunnel is:

[0037] Select the brightness point at the end of the first lamp loop in the middle segment as the starting interpolation point of the middle segment;

[0038] Select the brightness point at the beginning of the last lamp loop in the middle segment as the end interpolation point of the middle segment.

[0039] Beneficial effects of the present invention:

[0040] The present invention adjusts the lighting of each lighting section of the tunnel according to the brightness outside the tunnel, vehicle flow and vehicle speed in different time periods, and calculates the minimum lighting requirement of the tunnel based on the real-time brightness outside the tunnel, vehicle flow and vehicle speed data, thus making up for the deficiency of existing research that only considers the tunnel's design vehicle flow and design speed to calculate the tunnel lighting requirement.

[0041] The present invention reasonably selects interpolation points on the tunnel lighting demand segmented curve and uses the PCHIP interpolation method to perform smooth fitting of the interpolation points. The fitted smooth curve meets the minimum lighting demand of the tunnel and provides a more accurate division basis for the next stage of smooth curve segmented lighting.

[0042] The present invention takes the number of lamp circuits in a tunnel lighting section as a basis, subdivides each lighting section according to the layout width of the lamp circuit to obtain a plurality of small lighting sections, and takes values ​​on a fitted smooth curve to achieve a step-by-step transition of lighting requirements between the lighting sections of the tunnel, making up for the deficiency of existing research that only estimates lighting requirements according to the original length of the tunnel lighting section, and is beneficial to improving the driver's light adaptability and the safety of vehicle driving in the tunnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0044] Figure 1 It is a schematic diagram of a flow chart of a specific embodiment of the present invention;

[0045] Figure 2 is a graph of the minimum lighting requirement in a specific embodiment of the present invention;

[0046] Figure 3 is a fitting curve diagram fitted in step 3 of a specific embodiment of the present invention;

[0047] Figure 4 is a detailed lighting requirement diagram of the entrance section and the transition section in a specific embodiment of the present invention;

[0048] Figure 5 It is a curve diagram of the overall tunnel lighting demand in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0050] The present invention is further illustrated below in conjunction with specific embodiments. Those skilled in the art should understand that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention, and modifications to various equivalent forms of the present invention fall within the scope defined by the appended claims of this application.

[0051] The present invention utilizes tools such as an outside tunnel brightness meter and a traffic flow and speed detector to collect data on outside tunnel brightness, traffic volume, and speed of a highway tunnel in a certain period of time; according to the detailed rules, the minimum lighting demand values ​​of each lighting section of the tunnel entrance section, transition section, middle section, and exit section under the conditions of known outside tunnel brightness, traffic volume, and speed in the period are calculated; the boundary points of each lighting section are selected as interpolation points, and the PCHIP interpolation method is used for smooth fitting, and the obtained fitting curve meets the minimum lighting demand of each lighting section; the tunnel lighting sections that can be subdivided into lamp circuits are screened out, and each tunnel section is divided into a plurality of small lighting sections according to the number of lamp circuits of each lighting section of the tunnel, and the length of each small lighting section is determined by the layout width of each lamp circuit; on the smooth curve after fitting, each small lighting section is valued according to its length, and a tunnel lighting demand segmented curve based on the lamp circuits of each lighting section is obtained, so as to realize the refined fitting of the tunnel vehicle lighting demand.

[0052] The process of the present invention is described below by means of specific embodiments:

[0053] like Figure 1 As shown, the present invention provides a tunnel vehicle lighting control method based on PCHIP interpolation method, comprising the following steps:

[0054] Step 1: Use tools such as tunnel brightness meter and traffic flow and speed detector to collect tunnel brightness, traffic flow and speed data of a two-lane tunnel on the expressway during the period of 12:00-12:15;

[0055] Step 2: Calculate the minimum lighting requirement value of each lighting section in the tunnel according to the data obtained in step 1; wherein each lighting section includes: an entrance section, a transition section, a middle section, and an exit section;

[0056] The total length of the tunnel is l = 3780m, the entrance lighting length is TH1 = [0, 80] and TH2 = [80, 160], the transition lighting length is TR1 = [160, 270] and TR2 = [270, 380], the middle lighting length is IN = [380, 3720], the end point of the first lighting circuit in the middle section is IN0 = 460m, the starting point of the last lighting circuit in the middle section is IN1 = 3640m, the exit lighting length is EX1 = [3720, 3750] and EX2 = [3750, 3780], the tunnel outside brightness L during the period t = 15min 20 (cd / m 2)=2710.28(cd / m 2 ), traffic volume q = 146.00 (veh / t), vehicle speed V = 62.85 (km / h), single lane hourly traffic volume Q = 292.00 (veh / h / ln);

[0057] According to the above conditions, the calculation method of the minimum lighting demand value of each section is as follows:

[0058] Minimum lighting requirements for the entrance and transition sections:

[0059] The interpolation method is used to calculate the brightness reduction coefficient k of the entrance section. The calculation method is shown in Table 1 below:

[0060]

[0061] Table 1

[0062] Substituting the vehicle speed V = 62.85 (km / h) and the hourly traffic volume of a single lane Q = 292.00 (veh / h / ln) into Table 1, it can be obtained that the brightness reduction coefficient k in this period is 0.0164.

[0063] The minimum lighting requirements for entrance sections TH1 and TH2 are:

[0064] L th1 = k × L 20 =44.45(cd / m 2 )

[0065] L th2 =0.5×k×L 20 =22.22(cd / m 2 )

[0066] The minimum lighting requirements for transition sections TR1 and TR2 are:

[0067] L tr1 =0.15×L th1 =6.67(cd / m 2 )

[0068] L tr2 =0.05×L th1 =2.22(cd / m 2 )

[0069] Minimum lighting requirements for the intermediate and exit sections:

[0070] The interpolation method is used to obtain the minimum lighting demand L at different hourly traffic volume Q and vehicle speed V. in The calculation method is as follows in Table 2:

[0071]

[0072] Table 2

[0073] Substituting the vehicle speed V = 62.85 (km / h) and the hourly traffic volume of a single lane Q = 292.00 (veh / h / ln) into Table 2, we can obtain the minimum lighting demand L in the middle. in : 1.07(cd / m 2 ).

[0074] The minimum lighting requirements for exit sections EX1 and EX2 are:

[0075] L ex =3×L in =3.21(cd / m 2 )

[0076] L ex2 =5×L in =5.36(cd / m 2 )

[0077] By finding the minimum lighting requirement for each segment, we can obtain Figure 2 The minimum lighting demand curve L is shown;

[0078] Step 3: Select the boundary points of each lighting segment as interpolation points, perform smooth fitting through the PCHIP interpolation method, and obtain a fitting curve that meets the minimum lighting requirements of each lighting segment;

[0079] For setting the interpolation points, the specific methods include:

[0080] Selection of interpolation points for non-middle sections of tunnels and selection of interpolation points for middle sections of tunnels,

[0081] Among them, the method for selecting interpolation points in the non-middle section of the tunnel is:

[0082] The starting and ending points of the entire tunnel are taken as the two interpolation points (0, 44.45) and (3780, 5.36); for the entrance sections TH1 and TH2, the brightness point at the end of the lighting section is taken as the interpolation point of the lighting section (80, 44.45) and (160, 22.22); for the transition sections TR1 and TR2, the brightness point at the end of the lighting section is taken as the interpolation point of the lighting section (270, 6.67) and (380, 2.22); for the exit sections EX1 and EX2, the brightness point at the starting point of the lighting section is taken as the interpolation point of the lighting section (3720, 3.21) and (3750, 5.36);

[0083] The method for selecting interpolation points in the middle section of the tunnel is:

[0084] The lighting circuit in the middle section of the tunnel is 80m per circuit. The brightness point at the end of the first lighting circuit in the middle section is taken as the starting interpolation point of the middle section (460, 1.07), and the brightness point at the beginning of the last lighting circuit in the middle section is taken as the ending interpolation point of the middle section (3640, 1.07).

[0085] For all selected interpolation points, the PCHIP interpolation method is used for curve fitting, that is, the piecewise cubic Hermite interpolation polynomial interpolation method. This interpolation method can ensure the monotonicity and smoothness of the interpolation function. The obtained Figure 3 The smooth fitting curve L' shown can meet the minimum lighting requirements;

[0086] Step 4: Obtain the length of each lamp circuit in the lighting segment that can subdivide the lamp circuit, segment the fitting curve of the corresponding lighting segment according to the length of each lamp circuit, form a segmented curve based on the tunnel lighting demand of the lamp circuit of each lighting segment, and control the tunnel vehicle lighting according to the segmented curve, wherein the segmentation process is specifically as follows:

[0087] According to the fitting curve L', the brightness requirements of the entrance section TH1, the middle section IN, and the exit section EX2 in this embodiment are set to be constant values, and there is no need to subdivide the lamp circuit; for the lighting sections other than the entrance section TH1, the middle section IN, and the exit section EX2, it is set that the entrance section TH2, the transition section TR1, the transition section TR2, and the exit section EX1 in this embodiment have two lamp circuits respectively, which are evenly distributed in each lighting section, and the four lighting sections of the entrance section TH2, the transition section TR1, the transition section TR2, and the exit section EX1 are selected as the tunnel lighting sections that can subdivide the lamp circuit;

[0088] For the tunnel lighting section that can be subdivided into lamp circuits, the tunnel is divided into different small lighting sections according to the layout width of each lamp circuit in each lighting section. In this embodiment, the lamp circuits in each lighting section are evenly distributed, and the small lighting section interval TH after the entrance section is subdivided into circuits can be obtained. 2c1 =[80,120],TH 2c2 =[120,160], small lighting segment interval TR after the transition segment subdivision loop 1c1 =[160,215],TR 1c2 =[215,270],TR 2c1 =[270,325],TR 2c2 = [325,380], small lighting section interval EX after the exit section subdivision circuit 1c1 =[3720,3735],EX 1c2 =[3735,3750]; For the tunnel lighting section that cannot be subdivided into lamp circuits, the original lighting section is retained;

[0089] like Figure 4 As shown, for the entrance segment and transition segment of the subdivided circuit, the lighting demand value at the end point of each subdivided lighting segment on the fitting curve L' is taken as the segmented lighting brightness of the subdivided lighting segment, that is, the entrance segment TH 2c1 and TH 2c2 The required brightness value of the interval is L' th2c1p =35.24 and L' th2c2p =22.22, transition section TR 1c1 and TR 1c2 The required brightness value of the interval is L' tr1c1p =12.69 and L' tr1c2p =6.67, transition section TR 2c1 and TR 2c2 The required brightness value of the interval is L' tr2c1p =3.86 and L' tr2c2p =2.22; For the exit section that can be subdivided, the lighting demand value at the starting point of each subdivided lighting segment on the smooth curve is taken as the segmented lighting brightness of the subdivided lighting segment, that is, the exit segment EX 1c1 and EX 1c2 The required brightness value of the interval is L' ex1c1b =3.21 and L' ex1c2b =4.44;

[0090] Integrate the brightness values ​​of each lighting segment to get Figure 5 The refined tunnel lighting demand segmented curve diagram shown in the figure realizes the segmented transition between the lighting segments of the tunnel.

[0091] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A tunnel vehicle lighting control method based on PCHIP interpolation method, characterized in that: The steps include: Step 1: Obtain real-time tunnel brightness, traffic flow and speed data; Step 2: Calculate the minimum lighting requirement value of each lighting section in the tunnel according to the data obtained in step 1; wherein each lighting section includes: an entrance section, a transition section, a middle section, and an exit section; Step 3: Select the boundary points of each lighting segment as interpolation points, perform smooth fitting through the PCHIP interpolation method, and obtain a fitting curve that meets the minimum lighting requirements of each lighting segment; Step 4: Obtain the length of each lamp circuit in the lighting segment that can subdivide the lamp circuit, segment the fitting curve of the corresponding lighting segment according to the length of each lamp circuit, form a segmented curve based on the tunnel lighting requirements of the lamp circuit of each lighting segment, and control the tunnel vehicle lighting according to the segmented curve.

2. The tunnel vehicle lighting control method based on PCHIP interpolation method as claimed in claim 1, characterized in that: In step 2, the calculation method of the minimum lighting requirement value of the entrance section is: The entrance section is divided into two entrance lighting sections, and the calculation formulas are: L th1 =k×L 20 L th2 =0.5×k×L 20 Where, L th1 is the minimum lighting requirement value of the first entrance lighting segment; L th2 is the minimum lighting requirement value of the second entrance lighting segment; k is the brightness reduction coefficient of the entrance segment; L 20 The brightness outside the cave.

3. The tunnel vehicle lighting control method based on PCHIP interpolation method as claimed in claim 2, characterized in that: The specific formula of the brightness reduction coefficient is: Where Q is the traffic volume at different hours; V is the vehicle speed.

4. The tunnel vehicle lighting control method based on PCHIP interpolation method as claimed in claim 2, characterized in that: In step 2, the calculation method of the minimum lighting requirement value of the transition section is: The transition section is divided into three transition lighting sections according to the principle of gradual decrease, and the calculation formulas are: L tr =0.15×L th1 L tr2 =0.05×L th1 L tr3 =0.02×L th1 Where, L th1 is the minimum lighting requirement value of the first entrance lighting segment; L tr1 L is the minimum lighting requirement value of the first transition lighting segment; tr2 is the minimum lighting requirement value of the second transition lighting segment; L tr3 It is the minimum lighting requirement value for the third transition lighting segment.

5. The tunnel vehicle lighting control method based on PCHIP interpolation method as claimed in claim 1, characterized in that: In step 2, the calculation method of the minimum lighting requirement value of the middle section is: The traffic volume Q and vehicle speed V at different hours are calculated by interpolation method. The specific formula is as follows:

6. The tunnel vehicle lighting control method based on PCHIP interpolation method as claimed in claim 5, characterized in that: In step 2, the calculation method of the minimum lighting requirement value of the exit section is: The exit section is divided into two exit lighting sections, and the calculation formulas are: L ex =3×L in L ex =5×L in Where, L in is the minimum lighting requirement value of the middle section; L ex1 is the minimum lighting requirement value of the first exit lighting segment; L ex2 It is the minimum lighting demand value of the first exit lighting segment.

7. The tunnel vehicle lighting control method based on PCHIP interpolation method as claimed in claim 1, characterized in that: In step 3, the method for setting the interpolation points includes: Selection of interpolation points for non-middle sections of tunnels and selection of interpolation points for middle sections of tunnels, Among them, the method for selecting interpolation points in the non-middle section of the tunnel is: Select the starting and ending points of the entire tunnel as two interpolation points; select the brightness points at the end of the entrance section and the transition section as the interpolation points of the corresponding sections; select the brightness point at the starting point of the exit section as the interpolation point of the exit section; The method for selecting interpolation points in the middle section of the tunnel is: Select the brightness point at the end of the first lamp loop in the middle segment as the starting interpolation point of the middle segment; Select the brightness point at the beginning of the last lamp loop in the middle segment as the end interpolation point of the middle segment.

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