| CPC B60W 40/13 (2013.01) [B60W 40/06 (2013.01); B60W 2040/1315 (2013.01)] | 4 Claims |
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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 Δgi(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:
 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 ith measuring position is expressed as:
 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 ρj satisfy are formed:
 the values of ρj are solved according to the above n linear equations, then the mass density piecewise constant function ρ is determined according to ρj;
(2) when the interval distances between the measuring positions are different, the calculation process of the mass density piecewise constant function ρ of the vehicle is similar to that when the interval distances between the measuring positions are identical, except that
 in the above calculation formulas is replaced by
 wherein
 Lk, k=1,2, . . . n−1, is the distance between a kth measuring position and a (k+1)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 mtotal weight is expressed as:
 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.
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