A vehicle distance measurement method and system for improving distance measurement accuracy

Abstract

The present invention belongs to the field of sandbox model trolleys, and specifically relates to a trolley distance measurement method and system for improving distance measurement accuracy. The method includes: obtaining the number of the latest positioning point and the number of wheel rotations from the moment the trolley passes the latest positioning point to the current moment; determining the position information of the latest positioning point through the number of the latest positioning point to obtain the distance corresponding to the latest positioning point; the above-mentioned latest positioning point is the positioning point on the trolley track that the trolley recognizes when passing by the trolley for the last time; before the trolley passes the next positioning point, the distance between the trolley and the latest positioning point is obtained according to the above-mentioned number of wheel rotations and the wheel circumference of the trolley, and the real-time distance of the trolley is determined according to the distance between the trolley and the latest positioning point and the distance corresponding to the obtained latest positioning point, until the trolley passes the next positioning point on the trolley track, and the next positioning point is used as the latest positioning point.

Description

Technical Field

[0001] The invention belongs to the field of sandbox model trolleys, and in particular relates to a trolley distance measurement method and system for improving distance measurement accuracy. Background Art

[0002] Generally speaking, when measuring the real-time motion position (distance) of a moving car in a sandbox, the final positioning accuracy will be greatly reduced due to factors such as wheel friction, sensor accuracy, timer error, etc. Although the method of using real-time image collection of the car in the sandbox for positioning can achieve more accurate positioning, the computational cost of image processing and recognition is high.

[0003] A Chinese invention patent with application publication number CN102831794A discloses an automatic tracking technology for a model car in a track teaching sandbox, which adopts radio frequency tag positioning. The radio frequency tag number of each track sleeper is read during the movement of the model car, and the current position of the model car is determined by identifying the radio frequency tag number; the scheme uses the position of the track sleeper that the model car is passing through during the movement (that is, the radio frequency tag number of the track sleeper is read) as the current position of the model car, thereby realizing the ranging of the moving car in the sandbox. The scheme is simple, the calculation cost is low, and the positioning accuracy can be guaranteed to a certain extent, and there will be no situation where the deviation from the actual position is too large due to the error of the calculation parameters; however, the current position of the model car obtained by this method can only be the fixed position corresponding to the radio frequency tag of the track sleeper closest to the car, and the ranging accuracy is greatly limited by the distance between the radio frequency tags on the track. Summary of the invention

[0004] The purpose of the present invention is to provide a trolley ranging method and system for improving ranging accuracy, which is used to solve the problem that the ranging accuracy of the method of determining the current position of a model vehicle by the radio frequency tag number of a track sleeper read by the model vehicle is greatly limited by the distance between the radio frequency tags on the track.

[0005] In order to achieve the above-mentioned object, the present invention provides a trolley distance measurement method for improving the distance measurement accuracy, comprising: obtaining the number of the latest positioning point and the number of wheel rotations from the moment when the trolley passes the latest positioning point to the current moment; determining the position information of the latest positioning point through the number of the latest positioning point to obtain the distance corresponding to the latest positioning point; the latest positioning point is the positioning point on the trolley track identified by the trolley when it passes by for the last time;

[0006] Before the trolley passes the next positioning point, the distance between the trolley and the latest positioning point is obtained according to the number of rotations of the wheel and the circumference of the wheel of the trolley. The real-time distance of the trolley is determined according to the distance between the trolley and the latest positioning point and the distance corresponding to the obtained latest positioning point, until the trolley passes the next positioning point on the trolley track, and the next positioning point is used as the latest positioning point.

[0007] Furthermore, the number of wheel rotations is calculated by collecting the rotation action of the motor through a grating encoder, and obtaining the number of grating pulses from the moment the trolley passes the latest positioning point to the current moment, the grating encoder resolution, and the reduction ratio of the motor driving the trolley.

[0008] Furthermore, the grating encoder collects the rotation action of the motor to obtain the number of grating pulses from the moment the trolley passes the latest positioning point to the current moment, including: each time the trolley passes the latest positioning point, the grating pulse number is recounted from 0, and the grating pulse number from the moment the trolley passes the latest positioning point to the current moment is obtained according to the count value of the grating pulse number at the current moment.

[0009] Furthermore, the positioning points are arranged at certain distance intervals on the trolley track, and the distance intervals on uphill and downhill slopes and curves are smaller than the distance intervals on the straight track.

[0010] Furthermore, the distance interval on the straight track is greater than or equal to 20 cm and less than or equal to 40 cm.

[0011] Furthermore, the distance interval on uphill and downhill slopes and curves is greater than or equal to 10 cm and less than or equal to 15 cm.

[0012] Further, the distance between the trolley and the latest positioning point is obtained according to the number of rotations of the wheel and the circumference of the wheel of the trolley. According to the distance between the trolley and the latest positioning point and the distance corresponding to the obtained latest positioning point, the method of determining the real-time distance of the trolley includes:

[0013]

[0014] Where L is the real-time distance of the car; W(x) represents the distance corresponding to the latest positioning point, where x is the number of the latest positioning point; represents the distance between the car and the latest positioning point, where 2πr is the wheel circumference of the car and r is the wheel radius of the car; It represents the number of wheel rotations; N is the number of grating pulses obtained from the moment the car passes the latest positioning point to the current moment; C is the resolution of the grating encoder; D is the reduction ratio of the motor-driven car.

[0015] The above technical scheme of the present invention provides a new method for measuring the distance of a trolley for improving the accuracy of distance measurement, and its beneficial effects include: taking the positioning point at the trolley track identified by the trolley when the trolley passes the most recent time as the positioning reference, the position information of the positioning reference can be obtained through the number of the positioning reference, so as to obtain the distance corresponding to the positioning reference; thus, only according to the number of rotations of the wheel of the trolley between the moment when the trolley passes the positioning reference and the current moment, the distance traveled by the trolley after leaving the positioning reference (i.e. the distance between the trolley and the latest positioning point) can be obtained in combination with the wheel circumference of the trolley, and on the basis of the distance traveled by the trolley when it reaches the positioning reference (i.e. the distance corresponding to the positioning reference), combined with the distance traveled by the trolley in real time after leaving the positioning reference, the real-time distance of the trolley can be determined more accurately; this method is equivalent to supplementing the travel distance of the trolley between the two positioning points, so compared with the method of determining the current position of the model car only by the positioning points on the track in the prior art, the distance measurement accuracy is not limited by the distance between the positioning points on the track, and the distance measurement error can be effectively reduced.

[0016] The present invention also provides a vehicle ranging system for improving ranging accuracy, comprising a processor, wherein the processor is used to execute a computer program to implement the steps of the vehicle ranging method for improving ranging accuracy as described above.

[0017] The technical solution of the trolley ranging system for improving ranging accuracy of the present invention can achieve the same beneficial effects as the above-mentioned trolley ranging method for improving ranging accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a flowchart of a method for measuring distance between vehicles used to improve the accuracy of distance measurement, which is implemented by an embodiment of the method for measuring distance between vehicles used to improve the accuracy of distance measurement. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0020] Embodiment of a vehicle distance measurement method for improving distance measurement accuracy

[0021] This embodiment provides a technical solution for a trolley distance measurement method for improving the distance measurement accuracy. The method sets a positioning point on a sand table track, takes the latest positioning point passed by the trolley as the reference point for the trolley distance measurement, and obtains the corresponding distance traveled by the trolley after passing the reference point by the number of wheel rotations after the trolley passes the positioning point, that is, the relative distance between the trolley and the reference point, and the real-time distance of the trolley can be obtained by combining the distance of the reference point itself; and whenever the trolley passes a new positioning point, the new positioning point is used as a new reference point, and the distance and position of the trolley are updated in real time by the distance of the reference point; thus, the real-time distance of the trolley = the precise distance between the trolley and the reference point + the distance of the reference point itself. Compared with the existing method of directly obtaining the real-time distance of the trolley by the distance of the reference point itself, the distance measurement accuracy of the trolley distance measurement is not limited by the distance between the positioning points, and the distance measurement error is effectively reduced.

[0022] The trolley distance measurement method for improving the distance measurement accuracy of this embodiment is applicable to the distance measurement conditions where a sand table with positioning points is arranged on the track and a trolley is provided with positioning points (the device or apparatus corresponding to the positioning point can be arranged on both sides of the track or on the track, and the specific setting principle is not limited, and it can be combined with the identifier on the trolley to realize the positioning function. Similarly, the setting principle of the identifier on the trolley is not limited). Figure 1 The method specifically includes: obtaining the number of the latest positioning point and the number of wheel rotations from the moment when the trolley passes the latest positioning point to the current moment; determining the position information of the latest positioning point by the number of the latest positioning point to obtain the distance corresponding to the latest positioning point; the latest positioning point here is the positioning point on the trolley track identified by the trolley when it passes by for the last time;

[0023] Before the car passes the next positioning point, the distance between the car and the latest positioning point is obtained based on the number of wheel rotations from the time the car passes the latest positioning point to the current moment and the wheel circumference of the car. The real-time distance of the car is determined based on the distance between the car and the latest positioning point and the distance corresponding to the latest positioning point obtained, until the car passes the next positioning point on the car track, and the next positioning point is used as the latest positioning point.

[0024] The above-mentioned trolley distance measurement method uses the positioning point at the trolley track identified by the trolley when the trolley passes the most recent time as the positioning reference. The position information of the positioning reference can be obtained through the number of the positioning reference, thereby obtaining the distance corresponding to the positioning reference; therefore, only the number of wheel rotations of the trolley between the moment when the trolley passes the positioning reference and the current moment can be combined with the wheel circumference of the trolley to obtain the distance traveled by the trolley after leaving the positioning reference (i.e., the distance between the trolley and the latest positioning point). On the basis of the known distance traveled by the trolley when it reaches the positioning reference (i.e., the distance corresponding to the positioning reference), combined with the distance traveled by the trolley in real time after leaving the positioning reference, the real-time distance of the trolley can be determined more accurately; this method is equivalent to a supplementary measurement of the travel distance of the trolley between the two positioning points. Therefore, compared with the method in the prior art that only determines the current position of the model car by the positioning points on the track, the distance measurement accuracy is not limited by the distance between the positioning points on the track, and the distance measurement error can be effectively reduced.

[0025] Among them, considering that the trolley is usually driven by a motor as a power source through multi-stage gear speed change with a high reduction ratio, the number of wheel rotations is calculated by the number of grating pulses obtained by the grating encoder from the moment the trolley passes the latest positioning point to the current moment, the grating encoder resolution, and the reduction ratio of the motor driving the trolley through the rotation action of the motor. Since the principle of obtaining the number of wheel rotations by the grating encoder actually belongs to the prior art, it will not be repeated here. In other embodiments, other prior arts can also be used to directly or indirectly measure the number of wheel rotations, and no excessive restrictions are made here.

[0026] Specifically, the grating encoder collects the number of grating pulses from the moment when the trolley passes the latest positioning point to the current moment by performing the rotation action of the motor, including: whenever the trolley passes the latest positioning point, the number of grating pulses is re-counted from 0, and the number of grating pulses from the moment when the trolley passes the latest positioning point to the current moment is obtained according to the count value of the number of grating pulses at the current moment. That is, when the trolley identifier recognizes the positioning point, the number of pulses is set to zero, and the position of the current positioning point is recorded.

[0027] In summary, the distance between the car and the latest positioning point is obtained according to the number of wheel rotations from the time when the car passes the latest positioning point to the current moment and the wheel circumference of the car. According to the distance between the car and the latest positioning point and the distance corresponding to the latest positioning point, the method of determining the real-time distance of the car specifically includes:

[0028]

[0029] Where L is the real-time distance of the car; W(x) represents the distance corresponding to the latest positioning point, where x is the number of the latest positioning point; represents the distance between the car and the latest positioning point, where 2πr is the wheel circumference of the car and r is the wheel radius of the car; It represents the number of wheel rotations from the moment the car passes the latest positioning point to the current moment; N is the number of grating pulses obtained from the moment the car passes the latest positioning point to the current moment; C is the resolution of the grating encoder; D is the reduction ratio of the motor driving the car.

[0030] It should be noted that, in this embodiment, the positioning points are set at a certain distance interval on the trolley track, and the distance interval of the positioning points on the uphill and downhill and curves is smaller than the distance interval of the positioning points on the straight track. Among them, the distance interval of the positioning points on the straight track is greater than or equal to 20cm and less than or equal to 40cm; and the distance interval of the positioning points on the uphill and downhill and curves is greater than or equal to 10cm and less than or equal to 15cm. In other embodiments, the distance intervals and value ranges of the positioning points on different straight tracks, uphill and downhill and curves can also be flexibly set according to the size of the sandbox and the trolley and trolley track.

[0031] In this embodiment, the positioning point identifier is installed at the middle bottom of the trolley and the position identifier is ensured to be more than 1 cm away from the track (if there is a large slope, the distance should be appropriately increased) as an example to illustrate a certain process of applying the above-mentioned trolley distance measurement method:

[0032] First, the rotation motion of the motor is collected through the grating encoder, and the grating pulse is recorded, the vehicle speed is measured, and the speed is controlled through the single-chip microcomputer. The wireless communication module on the vehicle transmits these data to the background processor in real time. When passing the positioning point, the background processor is immediately notified of the positioning point ID (that is, the number of the positioning point) through the wireless communication module on the vehicle. Since the grating speed measurement has errors due to resolution problems, and the speed ratio between the wheel rotation and the motor rotation is certain, the motor speed is faster (usually the ratio of the motor speed to the wheel speed can be as high as 600:1, and can be even larger depending on different situations), the resolution error of the grating can be reduced to a smaller level by directly measuring the motor speed instead of the wheel speed to calculate the number of wheel rotations.

[0033] When the background processor receives the positioning point ID, that is, through the positioning point ID, it queries the specific position information of the positioning point, obtains the distance corresponding to the latest positioning point, calibrates the position of the trolley, and records the number of positioning pulses at the same time, and uses the difference between the number of pulses before the next positioning point passed by the trolley and the number of grating pulses at the current latest positioning point as the number of grating pulses from the moment the trolley passes the latest positioning point to the current moment (i.e., the method of obtaining the number of grating pulses when the grating pulse count value is not cleared to zero); or, if the grating pulse number is recounted from 0 every time the trolley passes the latest positioning point, the number of grating pulses from the moment the trolley passes the latest positioning point to the current moment is obtained according to the count value of the grating pulse number at the current moment (i.e., the method of obtaining the number of grating pulses when the grating pulse count value is cleared to zero); and, after receiving the positioning point ID, the background processor calculates in real time according to the grating pulse number, reduction ratio, wheel diameter, etc. obtained by the current grating encoder in accordance with the above-mentioned method of determining the real-time distance of the trolley, and obtains the distance between the trolley and the latest positioning point;

[0034] On the basis that the distance corresponding to the latest positioning point and the distance between the car and the latest positioning point are determined, the real-time distance of the car can be obtained according to the sum of the two. In the sandbox project of this embodiment, before using the above-mentioned car distance measurement method, the car that is simply positioned by the positioning point usually has an error of about 10cm; after using the above-mentioned car distance measurement method, the distance measurement error is basically controlled to about 1-2cm, and can be controlled within 1cm when traveling slowly.

[0035] Embodiment of a vehicle ranging system for improving ranging accuracy

[0036] This embodiment provides a technical solution for a trolley ranging system for improving ranging accuracy. The trolley ranging system includes a processor, which is used to execute a computer program to implement the steps of the trolley ranging method for improving ranging accuracy in the above-mentioned trolley ranging method embodiment for improving ranging accuracy.

[0037] Since the specific working process, principle and effect of the trolley ranging system have been described in detail in the above-mentioned trolley ranging method embodiment for improving ranging accuracy, they will not be repeated here.

[0038] Specific implementations are given above, but the present invention is not limited to the described implementations. Changes, modifications, substitutions and variations made to the implementations without departing from the principles and spirit of the present invention still fall within the protection scope of the present invention.

[0039] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, but do not constitute a limitation to the present invention.

Claims

1. A vehicle distance measurement method for improving distance measurement accuracy, characterized in that: include: Get the number of the latest positioning point and the number of rotations of the wheel from the moment the car passes the latest positioning point to the current moment; By using the number of the latest positioning point, the position information of the latest positioning point is determined to obtain the distance corresponding to the latest positioning point; The latest positioning point is the positioning point on the trolley track that the trolley identified when it passed the trolley the most recently; Before the trolley passes the next positioning point, the distance between the trolley and the latest positioning point is obtained according to the number of rotations of the wheel and the circumference of the wheel of the trolley. The real-time distance of the trolley is determined according to the distance between the trolley and the latest positioning point and the distance corresponding to the obtained latest positioning point, until the trolley passes the next positioning point on the trolley track, and the next positioning point is used as the latest positioning point.

2. The method for measuring distance with a vehicle for improving the accuracy of distance measurement according to claim 1, characterized in that: The number of wheel rotations is calculated by collecting the rotation action of the motor through a grating encoder, from the number of grating pulses from the moment the trolley passes the latest positioning point to the current moment, the grating encoder resolution, and the reduction ratio of the motor driving the trolley.

3. The method for measuring distance with a vehicle for improving the accuracy of distance measurement according to claim 2, characterized in that: The grating encoder collects the rotation action of the motor to obtain the number of grating pulses from the moment the trolley passes the latest positioning point to the current moment. The method includes: each time the trolley passes the latest positioning point, the grating pulse number is recounted from 0, and the grating pulse number from the moment the trolley passes the latest positioning point to the current moment is obtained according to the count value of the grating pulse number at the current moment.

4. The method for measuring distance with a vehicle for improving the distance measurement accuracy according to any one of claims 1 to 3, characterized in that: The positioning points are arranged at certain intervals on the trolley track, and the intervals on uphill and downhill slopes and curves are smaller than the intervals on straight tracks.

5. The method for measuring distance with a vehicle for improving the accuracy of distance measurement according to claim 4, characterized in that: The distance interval on the straight track is greater than or equal to 20 cm and less than or equal to 40 cm.

6. The method for measuring distance with a vehicle for improving the accuracy of distance measurement according to claim 4 or 5, characterized in that: The distance interval on uphill and downhill slopes and curves is greater than or equal to 10 cm and less than or equal to 15 cm.

7. The method for measuring distance with a vehicle for improving the accuracy of distance measurement according to claim 2 or 3, characterized in that: The distance between the trolley and the latest positioning point is obtained according to the number of rotations of the wheel and the circumference of the wheel of the trolley. The real-time distance of the trolley is determined according to the distance between the trolley and the latest positioning point and the distance corresponding to the obtained latest positioning point. The method includes: Where L is the real-time distance of the car; W(x) represents the distance corresponding to the latest positioning point, where x is the number of the latest positioning point; represents the distance between the car and the latest positioning point, where 2πr is the wheel circumference of the car and r is the wheel radius of the car; It represents the number of wheel rotations; N is the number of grating pulses obtained from the moment the car passes the latest positioning point to the current moment; C is the resolution of the grating encoder; D is the reduction ratio of the motor-driven car.

8. A vehicle ranging system for improving ranging accuracy, comprising a processor, characterized in that: The processor is used to execute a computer program to implement the steps of the vehicle ranging method for improving ranging accuracy as described in any one of claims 1 to 7.

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