CN101526548B - Measuring method of vehicle speed with circular coils - Google Patents

Abstract

The invention relates to measuring method with circular coils, which comprises the following steps: allowing a vehicle to pass through n coils and recording time values when the vehicle passes through each coil; measuring the distance between each two coils respectively; solving speeds by a formula V=S/T respectively, wherein S is the distance between each two coils, T is the time difference between the vehicle passing through a first coil and a second coil, and V is the speed of the vehicle; and screening speed values to determine whether the difference value between two speeds is always less than 20 percent, if one of the difference value is more than 20 percent, filtering the speed or displaying that the speed is not detected; and if the difference value is always less than 20 percent, performing weighted average on the obtained speeds so as to obtain the final speed. The measuring method can obtain the actual speed of the vehicle as much as possible.

Description

A kind of method of utilizing the toroid winding measurement of vehicle speed

Technical field

The present invention relates to a kind of measuring method of speed, relate in particular to a kind of method of utilizing the toroid winding measurement of vehicle speed.

Background technology

Vehicle detecting system is the very important part of road monitoring system, utilizing inductive coil to detect car speed (comprising motor vehicle and bicycle) is the comparatively ripe vehicle checking method of present technology in the world, it can obtain data such as current monitoring road traffic flow, occupation rate, speed, judge the road block situation with this, and utilize the outfield information issuing system to give a warning etc., especially playing an important role aspect the speed of measuring vehicle.Its ultimate principle is for to bury one group of inductive coil (two) underground in the road foundation section in same track, and every group of inductive coil links to each other with the hyperchannel wagon detector.When vehicle during respectively through two coils, because the variation of winding inductance quantity, the passing through state and will be detected of vehicle, status signal is transferred to wagon detector simultaneously, is gathered and is calculated by it.The method detects accurately, and equipment is stable, and still possesses outstanding performance under severe weather conditions, and cheap cost also is one of its reason that worldwide is able to widespread use.

The concrete principle of work of two coil detection techniques as shown in Figure 1, time when recording automobile through first coil and second coil respectively, and calculate the mistiming, and utilize distance and the mistiming of trying to achieve between first coil and second coil then, obtain the speed of automobile according to V=S/T.Because the uncertainty of vehicle driving trace, travel as non-rectilinear, non-at the uniform velocity travel etc., often make former and later two coils consistent inadequately to the detection of same car, thereby cause the Vehicle Speed and the actual speed deviation that obtain excessive, occur leaking car easily, emit at a high speed, emit low speed, rate accuracy high deficiency inadequately.

Summary of the invention

The present invention is consistent inadequately to vehicle detection for solving existing toroid winding detection technique, causes the shortcoming of the speed deviations actual speed that records, and a kind of method of utilizing the toroid winding measurement of vehicle speed is provided.

A kind of method of utilizing the toroid winding measurement of vehicle speed comprises,

Step 1, allow vehicle successively by n coil, and the time value when writing down by each coil respectively;

Step 2, record the distance between the coil in twos respectively;

Step 3, utilize formula V=S/T to try to achieve the speed of a motor vehicle respectively, wherein S is two distances between the coil, T be vehicle from entering first coil to entering second mistiming that coil is used, V is the speed of vehicle;

Step 4, velocity amplitude is screened, see that two differences between the speed of a motor vehicle whether all less than 20%, if having one greater than 20%, then do not detect speed filtering or display speed;

If the step 5 difference is all less than 20%, then the speed with gained is weighted on average, thus the final speed of obtaining.

N in the wherein said step 1＞4, n=3 or n=4 in the described step 1.

Wherein when n=3, obtain three velocity amplitude V1, V2 and V3 altogether, utilize method of weighted mean to obtain average velocity V, the formula that described method of weighted mean obtains mean value is:

V＝V1*a％+V2*b％+V3*c％

A+b+c=100 wherein, c 〉=a, c 〉=b, a=b, { { V be the vehicle average velocity of final acquisition to b ∈ to c ∈ for 20～100/3}, V1, V2, three velocity amplitudes of V3 for obtaining for 100/3～60}, a.

Error range between wherein said velocity amplitude V1, V2 and the V3 is less than 20%.

The present invention can obtain a plurality of car speeds owing to adopted a plurality of coil measuring methods, the row filter of going forward side by side, and the acquisition of energy maximum possible is the actual speed of vehicle accurately.

Description of drawings

Fig. 1 is two coil detection method process flow diagrams;

Fig. 2 is triple coil detection method process flow diagram.

Embodiment

Below in conjunction with a specific embodiment triple coil detection method of the present invention is described in detail, as shown in Figure 2,

At first, allow vehicle successively through first coil, second coil and tertiary coil, and the time value when writing down by each coil respectively, note is made t1, t2, t3;

Secondly, record between first coil and second coil apart between S1, second coil and the tertiary coil apart between S2, first coil and the tertiary coil apart from S3;

The 3rd utilizes formula V=S/T to try to achieve three speed of a motor vehicle respectively, be V1=S1/ (t2-t1), V2=S2/ (t3-t2), V3=S3/ (t3-t1), wherein S is two distances between the coil, T be vehicle from entering first coil to entering second mistiming that coil is used, V is the speed of vehicle;

The 4th, velocity amplitude is screened, if the difference between V1 and the V2, between V1 and the V3, between V2 and the V3 has one greater than 20%, then speed filtering or display speed are not detected;

The 5th, if the difference between V1 and the V2, between V1 and the V3, between V2 and the V3 then is weighted three speed V1, V2, V3 on average all less than 20%, thus the final speed of obtaining.

In above-mentioned steps four, judge that whether the difference between V1 and the V2 greater than 20% method is, judgment formula | whether V1-V2|/V2*100% is less than 20%, same reason is judged between V1 and the V3, whether the difference between V2 and the V3 is all less than 20%, can get through actual computation, all (wherein 20% threshold difference is the empirical value that obtains after by on-the-spot actual motion less than 20% the time when all speed difference between any two, the phenomenon that combines the accuracy requirement of test speed and avoid too much not measuring, generally between 10%～20%), vehicle driving track comparison rule, the car speed that records like this is just near actual value.

In above-mentioned calculating, difference between the speed has different requirements for different accuracy ratings, for when the bayonet socket interception car, can not miss any one vehicle, so precision is relaxed, difference can be loosened to 20%, when when hypervelocity checks, precision will reduce, and difference can not surpass 10%.

In the triple coil testing process, according to the calculating of theory, have higher rate accuracy with first velocity amplitude V3 with the 3rd coil acquisition.Therefore with V3 weight maximum, V1, V2 weight gentlier are weighted on average,

V＝V1*a％+V2*b％+V3*c％

A+b+c=100 wherein, c 〉=a, c 〉=b, a=b, { { 20～100/3}, V are the final car speed that obtains to b ∈ to c ∈ for 100/3～60}, a.

Can adopt a plurality of coils (more than three or three) to measure among the present invention, can obtain a plurality of car speeds, the row filter of going forward side by side so just can obtain the actual speed of vehicle as far as possible accurately.

Protection scope of the present invention is not limited thereto, and any those skilled in the art are not breaking away from the modification of making under the spirit of the present invention, and all within protection scope of the present invention, protection scope of the present invention is limited with claims.

Claims (6)

1. a method of utilizing the toroid winding measurement of vehicle speed is characterized in that, comprise,

Step 1, allow vehicle successively by n coil, and the time value when writing down by each coil respectively, wherein n 〉=3;

Step 2, record the distance between the coil in twos respectively;

Step 3, utilize formula V=S/T to try to achieve the speed of a motor vehicle respectively, wherein S is two centre distances between the coil, T be vehicle from entering first coil to entering second mistiming that coil is used, V is the speed of vehicle;

Step 4, velocity amplitude is screened, whether see difference between per two speed of a motor vehicle all less than 20%, judgment formula is | V _K1-V _K2|/V _K2* 100%, wherein, described V _K1Be first speed of a motor vehicle in per two speed of a motor vehicle, V _K2Be second speed of a motor vehicle in per two speed of a motor vehicle; If have one greater than 20%, then speed filtering or display speed do not detected;

If the step 5 difference is all less than 20%, then the speed with gained is weighted on average, thus the final speed of obtaining.

2. a kind of method of utilizing the toroid winding measurement of vehicle speed as claimed in claim 1 is characterized in that n in the described step 1＞4.

3. a kind of method of utilizing the toroid winding measurement of vehicle speed as claimed in claim 1 is characterized in that, n=3 or n=4 in the described step 1.

4. a kind of method of utilizing the toroid winding measurement of vehicle speed as claimed in claim 3, it is characterized in that, when n=3, obtain three velocity amplitude V1=S1/ (t2-t1), V2=S2/ (t3-t2), V3=S3/ (t3-t1) altogether, wherein, vehicle is successively through first coil, second coil and tertiary coil, and the time value when writing down by each coil respectively, and note is made t1, t2, t3; Record between first coil and second coil apart between S1, second coil and the tertiary coil apart between S2, first coil and the tertiary coil apart from S3; Utilize method of weighted mean to obtain average velocity V.

5. a kind of method of utilizing the toroid winding measurement of vehicle speed as claimed in claim 4 is characterized in that, the formula that described method of weighted mean obtains average velocity V is:

V＝V1*a％+V2*b％+V3*c％

A+b+c=100 wherein, c 〉=a, c 〉=b, a=b, { { V be the vehicle average velocity of final acquisition to b ∈ to c ∈ for 20～100/3}, V1, V2, three velocity amplitudes of V3 for obtaining for 100/3～60}, a.

6. a kind of method of utilizing the toroid winding measurement of vehicle speed as claimed in claim 4 is characterized in that, the error range between described velocity amplitude V1, V2 and the V3 is less than 20%.

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