Method for monitoring vehicle overload based on gravity anomaly

Abstract

Disclosed is a method for monitoring vehicle overload based on gravity anomaly, which includes the following steps of: setting a plurality of measuring positions on a single lane, arranging a gravimeter to acquire gravity anomaly values caused by a vehicle when the middle position along the length direction of the vehicle reaching each measuring position, using a monitoring camera to judge the category of the vehicle, acquire three geometric dimensions of the vehicle, and determine the position of the vehicle. The vehicle is simplified as a cuboid, and the mass density distribution is simplified as a piecewise constant function along the length direction of the vehicle. Calculating values of the piecewise constant function according to the gravity anomaly values, calculating a total weight of the vehicle according to the mass density distribution, comparing the total weight with the weight limit of the vehicle to judge whether the vehicle is overloaded.

Claims

1. A method for monitoring vehicle overload based on gravity anomaly, comprising the following steps: S1, setting a plurality of measuring positions on a single lane, and providing a monitoring device on an upper part of the single lane, wherein the monitoring device has a data acquisition device, a monitoring camera and a gravimeter; S2, determining, by the monitoring camera, a vehicle position, obtaining, by the monitoring camera, three geometric dimensions of length, width and height of a vehicle when the vehicle position reaching the measuring positions, comparing, by the data acquisition device, the vehicle with vehicle types stored in a database according the obtained three geometric dimensions of length, width and height to identify the category of the vehicle, and determining a weight limit of the vehicle based on the category of the vehicle, wherein the three geometric dimensions of length, width and height are maximum values of the vehicle in length, width and height directions, respectively, and the monitoring camera is arranged above the last measuring position in a driving direction; S3, using a gravimeter to obtain a gravity anomaly value g.sub.i(i=1,2, . . . , n) caused by the vehicle when a middle position in a length direction of the vehicle reaching each measuring position, wherein the gravimeter is arranged right above the intersection of the center line of the single lane and the measuring position, an orthogonal coordinate system is established by taking an intersection point of a center line of the single lane and an equidistance line of first and last measuring positions as an original point, and a spatial position of the gravimeter is recorded as (0, 0, H), where H represents a vertical height of the gravimeter from a ground; S4, simplifying the vehicle into a cuboid, wherein the length, width and height of the cuboid correspond to the three geometric dimensions of the vehicle, respectively; simplifying a mass density distribution into a piecewise constant function along the length direction of the vehicle, and calculating, by the monitoring device, values of the piecewise constant function according to the gravity anomaly value caused by the vehicle at each measuring position, which is specifically as below: (1) when interval distances between the measuring positions are identical, a mass density piecewise constant function p of the vehicle is expressed as follows: $={}_j,x[.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j-1}{m}a,.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j}{m}a)j=1,2,3,.Math.,m,i=1,2,3,.Math.,n,mn,$ where x is a horizontal coordinate of a certain point inside the vehicle, n is a number of the measuring positions, m is a number of values of the mass density piecewise constant function, L is the distance between the measuring positions and a is the length of the vehicle; the gravity anomaly value measured at the i.sup.th measuring position is expressed as: $g_i=G{}_{.Math.i-\left(n+1\right)/2.Math.L-a/2}^{.Math.i-\left(n+1\right)/2.Math.L+a/2}{}_{-b/2}^{b/2}{}_0^c\frac{z-H}{R^3}\mathrm{dzdydx},\mathrm{wherein}R={\left[x^2+y^2+{\left(z-H\right)}^2\right]}^{0.5},$ where G is the gravitation constant, b is the width of the vehicle, c is the height of the vehicle, y is a transverse coordinate of the point inside the vehicle, and z is a vertical coordinate of the point inside the vehicle; n gravity anomaly values are obtained from n measuring positions, and n linear equations which .sub.j satisfy are formed: $g_i=-G\underset{j=1}{\overset{m}{.Math.}}{}_j\left\{x\ln \left(y+R\right)+y\ln \left(x+R\right)-\left(z-H\right)\arctan \frac{\mathrm{xy}}{\left(z-H\right)R}\right\}{.Math.}_{x_1}^{x_2}{.Math.}_{y_1}^{y_2}{.Math.}_{z_1}^{z_2},\mathrm{wherein}{x}_1=.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j-1}{m}a,x_2=.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j}{m}a,y_1=-b/2,y_2=b/2,z_1=0,z_2=c,$ the values of .sub.j are solved according to the above n linear equations, then the mass density piecewise constant function is determined according to .sub.j; (2) when the interval distances between the measuring positions are different, the calculation process of the mass density piecewise constant function of the vehicle is similar to that when the interval distances between the measuring positions are identical, except that $.Math.i-\frac{\left(n+1\right)}{2}.Math.L$ in the above calculation formulas is replaced by $.Math.\underset{k=1}{\overset{i-1}{.Math.}}{L}_k-\frac{1}{2}{L}_{\mathrm{total}\mathrm{length}}.Math.,$ wherein $L_{\mathrm{total}\mathrm{length}}=\underset{k=1}{\overset{n-1}{.Math.}}{L}_k,$ L.sub.k, k=1,2, . . . n1, is the distance between a k.sup.th measuring position and a (k+1).sup.th measuring position; and S5, calculating an actual total weight of the vehicle according to the mass density distribution, the actual total weight of the vehicle m.sub.total weight is expressed as: $m_{\mathrm{total}\mathrm{weight}}=\underset{i=1}{\overset{m}{.Math.}}{}_i\frac{a}{m}\mathrm{bc},$ determining the weight limit corresponding to the category of the vehicle, comparing the actual total weight with the weight limit, and when the actual total weight exceeding the weight limit, determining, by the monitoring device, that the vehicle is overloaded, and not preventing the vehicle from continuing to run, so as to perform non-contact real-time measurement of the vehicle load without affecting the normal operation of road traffic.

2. The method for monitoring vehicle overload based on gravity anomaly according to claim 1, wherein the number of the measuring positions and the distances between the measuring positions can be determined according to requirements of road section speed limit and measuring accuracy, but the number of the measuring positions should not be less than one.

3. The method for monitoring vehicle overload based on gravity anomaly according to claim 1, wherein the gravimeter is arranged right above the intersection of the center line of the single lane and the equidistance line of the first measuring position and the last measuring position, and when there is only one measuring position, the gravimeter is arranged right above the intersection of the center line of the single lane and the measuring position, and the arrangement height should be greater than the road height limit.

4. The method for monitoring vehicle overload based on gravity anomaly according to claim 1, wherein the number of values of the mass density piecewise constant function is the same as or less than the number of the measuring positions.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The present disclosure will be further explained with reference to drawings and examples.

(2) FIG. 1 is a schematic flow chart of the implementation of the present disclosure;

(3) FIG. 2 is a schematic diagram of the layout of the measuring position and monitoring equipment;

(4) FIG. 3 is a schematic diagram of simplified size and mass density distribution of a vehicle.

(5) Reference signs: 1. The first measuring position, 2. The last measuring position, 3. Lane line, 4. Gravimeter, 5. Monitoring camera, 6. Vehicle, 7. Simplified cuboid.

DESCRIPTION OF EMBODIMENTS

(6) The purpose and effect of the present disclosure will become clearer by describing the present disclosure in detail according to the drawings and preferred embodiments. It should be understood that the specific embodiments described here are only used to explain the present disclosure, and are not used to limit the present disclosure.

(7) [Example 1]

(8) As shown in FIG. 1, a method for monitoring vehicle overload based on gravity anomaly of the present disclosure specifically includes the following steps:

(9) Setting several measuring positions on a single lane. Then using a monitoring camera 5 to determine the position of the vehicle 6, obtain the three geometric dimensions of length, width and height of the vehicle 6, and determine the weight limit of the vehicle 6 by judging the category of the vehicle 6. Obtaining the gravity anomaly value caused by the vehicle 6 when the middle position in the length direction of the vehicle 6 reaching each measuring position by using a gravimeter 4. Simplifying the vehicle 6 into a cuboid 7, and simplifying the mass density distribution into a piecewise constant function along the length direction of the vehicle 6; calculating the values of the piecewise constant function according to the gravity anomaly value caused by the vehicle 6 at each measuring position. Determining the total weight of the vehicle 6 according to the mass density distribution, and judging whether it is overloaded by comparing the total weight of the vehicle 6 with a weight limit of the vehicle 6.

(10) As shown in FIG. 2, in the monitored road section, n measuring positions are set on a single lane, where the first measuring position is 1 and the last measuring position is 2. The number of the measuring positions and the distance between the measuring positions can be determined according to the requirements of the road section speed limit and measuring accuracy, but the number of the measuring positions should not be less than 1, and the distance between two measuring positions can be the same or different. In this embodiment, the method will be explained with an equal interval of L.

(11) As shown in FIG. 2, a gravimeter 4 is arranged directly above the intersection point of the center line of a single lane and the equidistance line of the first measuring position 1 and the last measuring position 2; when there is only one measuring position, the gravimeter 4 should be arranged directly above the intersection point of the center line of the single lane and the measuring position. The height of the gravimeter 4 should be higher than the road limit height, and the gravity anomaly value g.sub.i(i=1, 2, . . . , n) caused by the vehicle 6 when the middle position in the length direction of the vehicle 6 reaching each measuring position is obtained by the gravimeter 4. In this embodiment, an orthogonal coordinate system is established by taking the intersection point of the center line of the single lane and the equidistance line of the first measuring position 1 and last measuring position 2 as the original point. At this time, the spatial position of the gravimeter 4 is recorded as (O,O,H), where H is the vertical height of the gravimeter 4 away from the road surface.

(12) As shown in FIG. 2, a monitoring camera 5 is arranged above the last measuring position 2 in the driving direction of the vehicle 6, and the position and angle of the monitoring camera 5 should be such that it can accurately capture each measuring position. By using the monitoring camera 5, the three geometric dimensions of the vehicle 6 passing by, i.e., length (a), width (b) and height (c), are obtained, the three geometric dimensions of length, width and height of the vehicle 6 are the maximum values of the vehicle 6 in the directions of length, width and height, respectively. By using the monitoring camera 5, the category of vehicle 6 is judged according to its size, and whether the middle position of the vehicle 6 along the length direction has reached the measuring position is judged.

(13) As shown in FIG. 3, the vehicle 6 is simplified into a cuboid 7. The length, width, and height of the cuboid 7 correspond to the three geometric dimensions of length, width, and height of the vehicle 6 respectively. The mass density distribution of the vehicle 6 is simplified into a piecewise constant function along the length direction of the vehicle 6. The number m of the values of the piecewise constant function is the same as or less than the number of the measuring positions n, and the values of the piecewise constant function are calculated according to the gravity anomaly value caused by the vehicle 6 at each measuring position. The calculation method is as follows:

(14) The spatial location of one point inside the vehicle 6 is expressed as (x, y, z).

(15) The mass density piecewise constant function p of the vehicle 6 is expressed as follows:

(16) $={}_j,x[.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j-1}{m}a,.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j}{m}a),j=1,2,3,.Math.,m,i=1,2,3,.Math.,n,mn,$ the gravity anomaly value measured at the i.sup.th measuring position is expressed as:

(17) $g_i=G{}_{.Math.i-\left(n+1\right)/2.Math.L-a/2}^{.Math.i-\left(n+1\right)/2.Math.L+a/2}{}_{-b/2}^{b/2}{}_0^c\frac{z-H}{R^3}\mathrm{dzdydx}\mathrm{where}R={\left[x^2+y^2+{\left(z-H\right)}^2\right]}^{0.5}$ G is a gravitation constant. n gravity anomaly values are obtained from n measuring positions, and n linear equations which p.sub.j satisfy are formed:

(18) 0$g_i=-G\underset{j=1}{\overset{m}{.Math.}}{}_j\left\{x\ln \left(y+R\right)+y\ln \left(x+R\right)-\left(z-H\right)\arctan \frac{\mathrm{xy}}{\left(z-H\right)R}\right\}{.Math.}_{x_1}^{x_2}{.Math.}_{y_1}^{y_2}{.Math.}_{z_1}^{z_2}\mathrm{where}{x}_1=.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j-1}{m}a,x_2=.Math.i-\frac{\left(n+1\right)}{2}.Math.L-\frac{a}{2}+\frac{j}{m}a,y_1=-b/2,y_2=b/2,z_1=0,z_2=c$ where the values of p.sub.j are solved according to the above n linear equations, then the mass density piecewise constant function p is determined according to p.sub.j.

(19) According to the determined mass density piecewise constant function , the total weight of the vehicle 6 is calculated in real-time as follows:

(20) $m_{\mathrm{total}\mathrm{weight}}=\underset{i=1}{\overset{m}{.Math.}}{}_i\frac{a}{m}\mathrm{bc}$ where m.sub.total weight is the total weight of the vehicle 6.

(21) The weight limit m.sub.weight limit corresponding to the category of the vehicle 6 is determined.

(22) According to the total weight and weight limit of the vehicle 6, if the total weight exceeds the weight limit, that is, m.sub.total weight>m.sub.weight limit, it is judged that the vehicle 6 is overloaded. The overloaded vehicle information is sent to a traffic management law enforcement department located downstream of the monitoring device to intercept the relevant vehicles.

(23) [Example 2]

(24) The distance between two measuring positions can be set to different values according to the actual road conditions. When different interval distances are adopted,

(25) $.Math.i-\frac{\left(n+1\right)}{2}.Math.L$
in the above calculation formulas is replaced by

(26) $.Math.\underset{k=1}{\overset{i-1}{.Math.}}{L}_k-\frac{1}{2}{L}_{\mathrm{total}\mathrm{length}}.Math.,$ where

(27) $L_{\mathrm{total}\mathrm{length}}=\underset{k=1}{\overset{n-1}{.Math.}}{L}_k,$ L.sub.k,k=1, 2, . . . n1, is the distance between the k.sup.th measuring position and the (k+1).sup.th measuring position.

(28) Those skilled in the art can understand that the above is only a preferred example of the present disclosure, and is not used to limit the present disclosure. Although the present disclosure has been described in detail with reference to the aforementioned examples, for those skilled in the art, they can still modify the technical solutions described in the aforementioned examples, or replace some of the technical features equally. All modifications and equivalent substitutions within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.