WO2013187799A2 - Method and system for increasing the accuracy of weighing a motor vehicle in motion - Google Patents

Description

 METHOD AND SYSTEM OF INCREASING PRECISION

 WHEN WEIGHTING A VEHICLE

IN MOVE

FIELD OF THE INVENTION

The present invention relates to a technique for weighing vehicles, in particular, in the process of weighing in (WIM) along a highway.

State of the art

Weighing of vehicles in the process of their movement along the highway is becoming increasingly important both for the control of transported goods and for charging tolls and (or) reloading.

 Typically, a vehicle is weighed on a platform equipped with stationary scales when entering a toll or controlled highway, as well as on similar sites organized on the highway itself (RF patent for utility model 88469, publ. 10.11.2009; US patent N ° 6980093, publ. December 27, 2005). It is clear that in this case weighing gives a static value and requires stopping the movement and entering a special area equipped with a weighing device of sufficiently high accuracy. Therefore, talking about weighing in the process of movement for such a method of weighing can only conditionally.

Nowadays, the weighing of vehicles directly in the process of their movement is increasingly used. For example, the site http://www.cross.cz/en/wim-weigh-in-motion describes a method for weighing vehicles when they move along a highway equipped with weight sensors that make it possible to determine pressure on the road surface from each passing axle or even each passing wheel of a particular motor vehicle. Reader devices are installed near such weight sensors, which allow one or another identification mark of a motor vehicle passing at that moment by a weight sensor to be read. The read data along with the time stamp are sent to the data processing center, where they are processed using a special program to determine the load on the roadway and, if necessary, to issue the corresponding receipt for payment.

 However, in such systems, which just got the name

“Weighing in motion” (WIM), the sensors used have low measurement accuracy due to the technological features of their manufacture and installation, as well as due to significant dependence on weather conditions, time of day and time of year . Therefore, on such routes, accurate scales must be used, as a rule, at the beginning or at the end of the route (US patent N ° 7684946, publ. 03.23.2010). In this case, the data from the weight sensors located in the He (WIM) roadway are used only for preselection, i.e. for a preliminary assessment of the overload factor and the need for accurate weighing on a static balance.

Disclosure of invention

The purpose of the present invention is to develop a method and system for improving accuracy when weighing a vehicle in motion, which would significantly improve the accuracy of measurements of weight sensors installed on the track, without the use of separate accurate weights, which ultimately reduces the cost of used equipment. To solve this problem and achieve the indicated technical result, the first object of the present invention proposes a method for improving the accuracy of weighing a vehicle in motion using at least one group of sensors for mass or axial weighing of a vehicle placed on the track, consisting in the following: at least one additional group of sensors is placed on the track for wheel or axial weighing of a vehicle at a distance from the previous a group in the direction of travel of at least the maximum possible length of the weighed vehicle; remember, as the first measuring readings, the readings of each of the sensors of the group placed first in the direction of movement on the mentioned track in any pair of sensor groups when each wheel or each axle of a particular motor vehicle passes along it; remember, as the second measurement readings, the readings of each of the sensors of the group placed next in the direction of movement on the track in a pair of groups of sensors, when each wheel or each axle of a particular motor vehicle passed through the previous sensor group in the same pair of sensor groups; find the average values of the first and second measurement readings corresponding to a particular wheel or axle of the vehicle and take them as the resulting readings of the weight of a given wheel or axle; the corresponding correction factors are calculated by comparing the weight indications of each wheel or axle measured by each of the sensors of the group or each of the groups of sensors in the lane of the vehicle with the corresponding average values found and the calculated correction factors are used to correct their readings when weighing next motor vehicle. A feature of the method of the present invention is that each of the groups of sensors can include at least two sensors for weighing or axially weighing the vehicle, spaced along the track in the direction of travel by less than the smallest possible length of the vehicle being weighed.

 Another feature of the method according to the present invention is that as the measuring readings of the sensors of this group can take the average readings of all the sensors included in it.

 Another feature of the method of the present invention is that as the measuring readings of each of the sensors of this group can take the readings of the corresponding sensors of this group when passing through it each of the wheels or each of the axles of a particular vehicle, measured relative to readings of sensors of another group in a pair of groups of sensors measured at the same moment in time.

 Another feature of the method of the present invention is that it can recognize a vehicle when it passes another of the groups of sensors, for which they install near the first in the direction of movement of the sensor groups a reading means for reading the corresponding identification marks with which vehicles are equipped.

To solve the same problem and achieve the same technical result, the second object of the present invention proposes a system for improving the accuracy of weighing a vehicle in motion, containing at least two groups of sensors for the generation or axial weighing of a vehicle, one of which is placed on the track in the direction of travel at a distance from of the previous group not less than the maximum possible length of the weighed vehicle, and a computing unit to which the sensors of both groups of sensors are connected and which is designed to carry out the steps in which: as the first measurement readings, the readings of each of the sensors of the group are stored, placed first in the direction of travel on the track in any pair of groups of sensors when driving on it each of the wheels or each of the axles of a particular vehicle; remember, as the second measurement readings, the readings of each of the sensors of the group, placed next in the direction of movement on the mentioned track in a pair of groups of sensors, when each wheel or each axle of a particular motor vehicle passes through it the previous sensor group in the same pair of sensor groups; find the average values of the first and second measurement readings corresponding to a particular wheel or axle of the vehicle and take them as the resulting readings of the weight of a given wheel or axle; the corresponding correction factors are calculated by comparing the readings of the weight of each wheel or axle measured by each of the sensors or each of the groups of sensors of the measuring complex in the lane of the vehicle with the corresponding average values found and the calculated correction coefficients are used to correct their readings when weighing the next motor vehicle.

A feature of the system of the present invention is that each of the groups of sensors can include at least two sensors for full-weight or axial weighting of a vehicle, spaced along the track in the direction of travel by less than the smallest possible length of a weighed vehicle. Another feature of the system of the present invention is that, as the measuring readings of the sensors of this group, the average readings of all the sensors included in it can be taken.

 Another feature of the system of the present invention is that, as the measuring readings of each of the sensors of a given group, the readings of the corresponding of the sensors of this group when driving along each of the wheels or each axle of a particular vehicle, measured relative to the readings of the sensors another group in a pair of groups of sensors measured at the same time.

 Another feature of the system of the present invention is that the system may further comprise a reading means in the vicinity of at least the first in the direction of movement of the groups of sensors, designed to read the corresponding identification marks with which vehicles are equipped.

Brief Description of the Drawings

The invention is further illustrated by the drawing, which shows a schematic diagram of a system in which the method of the present invention is implemented.

DETAILED DESCRIPTION OF THE INVENTION

As shown in the drawing, the method of the present invention can be implemented in a system in which two groups of sensors 3 and 4 are installed on track 1 (conventionally shown as one-sided and single-lane with the direction of movement in arrow 2), each having two sensors (weighing devices). In the drawing, the sensors of the first group 3 have reference numbers 31 and 32, and the sensors of the second group 4 have reference positions 41 and 42, and the sensors 31 and 41 are the first in the corresponding of groups 3 and 4 when counting in the direction of movement 2.

 Groups 3 and 4 are placed on track 1 at a distance R from one another in the direction of travel, and the distance R is not less than the maximum possible length of the weighed vehicle. For example, this distance R may exceed 20 m for routes on which the passage of lengthy freight vehicles is allowed. Note that a vehicle in this description can be understood not only as a truck or road train, but also as a tractor, tractor, etc.

 The sensors 31 and 32 in the first group 3 and the sensors 41 and 42 in the second group 4 are placed on the track at a distance L from one another in the direction of travel, and the distance L is less than the minimum possible length of the weighed vehicle. For example, this distance L may be less than 5 m. Note that both the overall size of this vehicle and the distance between its front and rear axles can act as the length of the vehicle.

As sensors (weighing devices) 31, 32, 41, 42, any weight sensors currently known or being developed in the future can be used. For example, these may be the sensors used in the Czech Cross weighing instruments mentioned above; or fiber optic sensors described in the RF patent for utility model J ° 13925 (publ. 10.06.2000), in US patents 4560016 (publ. 24.12.1985) and Jfc 5260520 (publ. 09.1 1.1993), in the application of the UK N ° 2250813 (published on June 17, 1992) or in Korean application N ° 2004/0102878 (published on 12/08/2004); or can strain gauges described in RF patents Ν ° 2239798 (publ. 10.1 1.2004) and Ν_ be used as such sensors? 2390734 (publ. May 27, 2010) or in the application of Korea J4 ° 2008/0105371 (publ. 04/12/2008). In principle, the specific design of the sensors 31, 32, 41, 42 it does not matter, and it does not matter whether they are all made the same or using different technologies.

 Sensors (weighing devices) 31, 32, 41, 42, as a rule, are placed in the roadway of track 1 in each lane across the direction 2 of the movement of vehicles. This arrangement of sensors allows you to measure the weight of the vehicle axially. If it is required to determine the weight generationally, each of the sensors 31, 32, 41, 42 can be divided into two parts, as described, for example, in the aforementioned RF patent N ° 2390734 and as shown in the drawing. It is advisable to place groups of 3 and 4 sensors where the speed of the vehicle is expected to be constant, i.e. on relatively straight sections of track 1, having unevenness in height and slopes of no more than predetermined values. Typically, the length of such segments, their slopes and unevenness in height, and possibly some other parameters, are set by the manufacturers of the respective weighing systems.

 Specialists understand that the number of sensors in each group is not necessarily equal to two. In principle, each group may contain one or more sensors, which does not affect the scope of the claims of this invention.

As shown in the drawing, an induction loop 5 can be placed in front of each of the sensors 31, 32, 41, 42. In principle, such induction loops 5 can be installed only before the first sensors in each direction in the direction of movement (i.e. in front of sensors 31 and 41). Each induction loop 5 serves to indicate a collision of a vehicle with a sensor located behind it. While the axles of the same vehicle (or the axles of its trailer) pass through this sensor, the electric potential is induced in this induction loop due to the mass of the vehicle moving over it. But as soon as this vehicle goes through the sensor located behind this induction loop 5, the induced potential in this induction loop 5 will sharply decrease, which can be determined by a separate threshold circuit. Hitting the same sensor of another vehicle, even driving almost “close to” the one who has already passed, will cause a new increase in potential in induction loop 5, which will also be recognized by the corresponding threshold circuit. Specific types of threshold schemes are well known to those skilled in the art.

 The signals from all the sensors of both groups 3 and 4 and from all the induction loops 5 enter the computing unit 6. In the drawing, the connections from the sensors 31, 32, 41, 42 to the computing unit 6 are conventionally shown as single lines, however, in the case of the above separation sensors for generational weighing, each half of the sensor will have its own connecting line to the computing unit 6.

Near at least the first group of 3 sensors in a pair of groups of 3 and 4 sensors can be installed reading means (not shown in the drawing). Each such reading means is arranged to read at least one of the identification marks that the vehicle is equipped with. Such identification marks can be both state registration numbers, and, for example, radio-identification tags (radio-identifiers, RFIDs) fixed on motor vehicles. In this case, the reading means is, for example, a video camera and (or) a reader (reader), the execution of which allows the identification marks of the corresponding type to be read. When a vehicle passes through the first in a pair of group of 3 sensors, a nearby reading device simultaneously fixes the reading time. For example, when using a video camera as a means of counting, such time fixing is performed automatically. Computing unit 6 performs the necessary data processing, described in detail below. To this end, the computing unit 6 may contain respectively programmed processor means (computer, processor, controller, etc.) and a memory for storing data received from sensors 31, 32, 41, 42, induction loops 5, as well as from reading means, if installed, and for storing the resulting data obtained as a result of processing the received data. Specific possible embodiments of the programmed processor means and memory are known to those skilled in the art.

 In the system shown in the drawing, a method of improving accuracy when weighing a vehicle in motion according to the present invention is carried out as follows.

 When a certain vehicle passes through a group of 3 sensors located first in a pair of groups of 3 and 4 sensors on track 1, the sensors 31, 32 of this group 3 generate signals proportional to the weight of each axis or each wheel of a passing vehicle. The readings of each of the sensors of group 3 when driving along this group of sensors of each of the wheels or each of the axles of a particular vehicle are stored in the computing unit 6 as the first measurement readings for this vehicle. In the same way, the readings of each of the sensors of the group of 4 sensors located after the group of 3 sensors in the direction of motion 2, when passing along this group of sensors of each of the wheels or each of the axles of the same vehicle, are stored in the computing unit 6 in as the second measurement reading for this vehicle.

In principle, the readings of the sensors 31 and 32 in the first group of 3 sensors and the readings of the sensors 41 and 42 in the second group of 4 sensors when passing through the same vehicle can be averaged over activities in each of the groups of 3 and 4 sensors. Then, as the measuring readings in the computing unit 6, these averaged values are stored. However, another option is also possible when, when traveling through some kind of sensor (let it be for certainty sensor 31) of the first group 3 of one of the axles (one of the wheels) of the vehicle at the same time the weight reading is recorded with this sensor (31) corresponding sensor (i.e., sensor 41) in the second group 4 of this pair of groups of 3 and 4 sensors. This indication of the sensor (41) of the second group 4 is used as a reference for measurements of the corresponding sensor (31) of the first group 3. The same measurement is carried out when the vehicle passes the sensors of another group 4, but now the sensors of the first group 3 work as supporting. At the same time, it is possible to minimize the influence of the environment on the readings of the sensors, since the placement of groups of 3 and 4 sensors close to one another gives the right to consider the environmental conditions the same for both groups of 3 and 4 sensors. In this case, in the computing unit 6, the signals of certain sensors, respectively corrected (reduced) by the values of the corresponding reference measurements, are stored as measuring readings.

As already noted, the sensors 31, 32, 41, 42 can preferably have a relatively simple design and, consequently, low accuracy (otherwise they would have sharply increased the cost of the system), which does not allow them to be used for legitimate claims for excess weight by controlled tracks without control weighing on more accurate static scales. The accuracy of the readings of these sensors can be improved by using at least one more accurate balance in the chain of sequentially located weight posts, correcting by the readings of these exact scales for a particular motor vehicle. However, this requires complication and appreciation of the system used. Therefore, in the present invention, the accuracy is improved differently.

 As is known, the accuracy of statistical estimates can be significantly improved by averaging several independent random events. Indeed, the standard deviation (which characterizes accuracy) for the average of the total of independent quantities is inversely proportional to the square root of these quantities (Handbook of Probabilistic Calculations. - M.: Military Publishing House, 1970. - P. 297) . Obviously, the sensors included in different groups 3 and 4 can be considered independent. Therefore, the accuracy of the averaged estimate for the sensors of both groups 3 and 4 with respect to a random error will increase to the square root of two, i.e. about 1.41 times.

 Therefore, for the stored values of the first and second measuring readings, in the computing unit 6, the average values corresponding to a particular wheel or axle of the vehicle are found and taken as the resulting readings of the weight of the given wheel or axle for that vehicle. Moreover, in the computing unit 6, the corresponding correction factors are calculated. This is done by comparing the weight readings of each wheel or axle, measured by each of the sensors in the group or each of the groups of sensors in the lane of the vehicle, with the corresponding average values found. The calculated correction factors are used to correct the readings when weighing the next vehicle using groups 3 and 4 of the sensors.

It will be understood by those skilled in the art that such pairs of groups of 3 and 4 sensors can be placed on track 1 repeatedly. The data obtained by the computing units 6 of each such pair of groups of 3 and 4 sensors can be transmitted to the processing center (not shown in the drawing) together with the identification data of the corresponding vehicle obtained using the aforementioned reading means. This data can be used both to improve the accuracy of the remaining groups of sensors on track 1, and for other purposes.

 But even in the absence of a processing center, repeated measurements of the weight of a vehicle using the described pair of groups of sensors, followed by averaging of the results and correction of readings according to this invention, can improve the accuracy of measuring the weight of a vehicle due to repeated repetitions of "double" weight measurements. Theoretically, the initial accuracy of each of the sensors in such pairs of groups after each measurement and corresponding correction will increase and tend to the potential accuracy of the sensor itself, measured in laboratory conditions without the influence of systematic and random errors, and at a certain stage to achieve the accuracy of the reference (mainly strain gauge) sensors used in the final measurement of weight on static weights on strips.

Claims

Claim 1. A method of improving accuracy when weighing a vehicle in motion using at least one group of sensors for the axial or axial weighing of a vehicle located on the track, namely:  - place at least one additional group of sensors on the track for wheel or axial weighing of the vehicle at a distance from the previous group in the direction of travel of at least the maximum possible length of the weighed vehicle;  - remember, as the first measurement readings, the readings of each of the sensors of the group placed first in the direction of movement on the mentioned track in any pair of the mentioned groups of sensors when each wheel or each axle of a particular motor vehicle passes through it;  - remember, as the second measurement readings, the readings of each of the sensors of the group located next in the direction of movement on the mentioned track in the mentioned pair of sensor groups when each wheel or each axle of the said particular vehicle passes through it who drove before this through the previous group of sensors in the same pair of groups of sensors;  - find the average values of the first and second measuring readings corresponding to a particular wheel or axle of the vehicle and take them as the resulting readings of the weight of this wheel or axle; - calculate the corresponding correction factors when comparing the weight indications of each wheel or axle measured by each of the sensors of the group or each of the groups of sensors in the lane of the data vehicle, with the corresponding average values found, and use the calculated correction factors to correct their readings when weighing the next vehicle.  2. The method according to claim 1, in which each of the mentioned groups of sensors includes at least two sensors for full-weight or axial weighting of a vehicle, spaced along the track in the direction of travel by less than the smallest possible length of the weighted vehicle.  3. The method according to claim 1 or 2, in which the averaged readings of all sensors included in it are taken as the mentioned measurement readings of the sensors of this group.  4. The method according to p. 1, in which, as mentioned measuring readings of each of the sensors of a given group, the readings of the corresponding sensors of this group are taken while each wheel or each axle of a particular motor vehicle passes through it, measured with respect to the sensor readings another group in said pair of groups of sensors measured at the same time.  5. The method according to p. 1, in which the recognition of the vehicle during its passage of the next of the mentioned groups of sensors, for which they install near the at least the first in the direction of movement of the mentioned groups of sensors reading means for reading appropriate identification tags with which vehicles are equipped.  6. A system for improving accuracy when weighing a vehicle in motion, comprising: - at least two groups of sensors for mass or axial weighing of a vehicle, one of which is located on the track in the direction of travel at a distance from the previous groups not less than the maximum possible length of the weighed vehicle;  - a computing unit to which the sensors of both of the mentioned groups of sensors are connected and which is designed to carry out the steps in which:  - remember, as the first measurement readings, the readings of each of the sensors of the group placed first in the direction of movement on the mentioned track in any pair of the mentioned groups of sensors when each wheel or each axle of a particular motor vehicle passes through it;  - remember, as the second measurement readings, the readings of each of the sensors of the group located next in the direction of movement on the mentioned track in the mentioned pair of sensor groups when each wheel or each axle of the said particular vehicle passes through it who drove before this through the previous group of sensors in the same pair of groups of sensors;  - find the average values of the first and second measuring readings corresponding to a particular wheel or axle of the vehicle and take them as the resulting readings of the weight of this wheel or axle;  - calculate the corresponding correction coefficients when comparing the weight indications of each wheel or axle measured by each of the sensors or each of the groups of sensors of the measuring complex in the lane of the vehicle with the corresponding average values found and use the calculated correction coefficients for correction their testimony when weighing the next vehicle. 7. The system according to claim 6, in which each of these groups of sensors includes at least two sensors for generation or axis weighing the vehicle, spaced along the highway in the direction of travel by an amount less than the minimum possible length of the weighed vehicle.  8. The system according to claim 6 or 7, in which, as the mentioned measuring readings of the sensors of this group, the average readings of all the sensors included in it are accepted.  9. The system according to claim 6, in which, as mentioned measuring readings of each of the sensors of a given group, the readings of the corresponding sensors of this group when each wheel or each axle of a particular vehicle passes through it, measured relative to the readings of the sensors of another groups in said pair of groups of sensors measured at the same time.  10. The system of claim 6, further comprising a sensing means in the vicinity of at least the first in the direction of movement of said sensor groups, for reading the corresponding identification marks with which vehicles are equipped.