CZ2000746A3 - Calibration method of apparatus for measuring velocity or distance - Google Patents

Abstract

The present method uses a vehicle 1) equipped with a pulse a generator (2) for generating transmitting pulses mounted gearbox (3) and intended for taxiing along a path (4) of known length. The length of the track (4) is limited an initial signal indicator (5) and a signal signal signal (6). On track (4), they are in mutual intersection from the notched undercuts in the shape of a "V", activated through the vehicle installed on the vehicle (1). The signal processing means (7) is for counting the number of integral impulses and determining the pulse widths of the pulses in the area of the start and finish signal lights (5.6). The microprocessor adjusts the signal combining time intervals representing a fraction of pulse widths in the initial region a target signal light (5.6) with total integral impulses of the added fractions to the number of pulses read and thus accurately determines how many pulses and any pulse fractions are generated during vehicle travel (1) after expensive (4) between the initial target signal signal (5,6).

Description

METHOD OF CALIBRATION OF SPEED OR DISTANCE DEVICES

Technical field

The present invention relates to a method of calibrating a speed and / or distance measuring device as part of a vehicle equipment.

BACKGROUND OF THE INVENTION

Virtually all road motor vehicles require equipment to indicate speed. Traditionally, such means utilize an output torque derived from the output shaft output shaft for this purpose. The torque is then transferred to the speed indicator (tachometer / tachograph) via the rotary cable. In connection with automobiles, the ratio between speed or distance and rotation of this cable is usually predetermined and unchangeable for each particular model line of the automobile. Commercially available vehicles are generally fitted with an extensive range of gearbox, axle and tire versions. This results in a wide range of variations in the gear ratio between the output of the gearbox and the rotation of the wheel, even if only in connection with a single vehicle model line. It is therefore necessary that said rate indicator be adapted to accept such variations. In addition, it is also necessary to precisely identify and determine the corresponding «4» 4.

In the case of the mutual ratio for each given model of the tachograph vehicle, then, from the point of view of the mentioned ratio, it is absolutely a regular requirement to define it at regular intervals. In the case of vehicles with mechanical drive of the tachometer / tachograph, the determined value is the number of revolutions at the gearbox output for each kilometer of distance traveled by the vehicle. This value, or calibration coefficient, is often known as the W coefficient of a vehicle.

Although the rotating cables are simple in design, they represent a number of pitfalls. Especially in commercially available vehicles, these have largely been replaced by speed / distance transmitters that produce electrical impulses during vehicle movement). The calibration coefficient (W-coefficient) of the vehicle then represents the number of electrical impulses per kilometer of the distance traveled by the vehicle. In this case too, this coefficient must be determined separately for individual vehicles. Characteristically, W-coefficients of commercially available vehicles range from (say) 2,500 to 25,000, although other values are possible and likely.

For the purpose of accurately determining the W-coefficient of a vehicle, the vehicle must travel along a distance of known distance, counting the number of pulses generated from the transmitter to indicate the speed / distance during vehicle travel over that distance. A system of this type is described in detail in Japanese Patent Application JP 6834982, published under JP 58193468.

Under the circumstances, taking into account the impulses generated from the

When the calibration test is performed, the beginning of the known distance will usually occur between approximately one of the leading edges of the pulse and the following when performing the calibration test. edge. In the case of the simple citation pulses generated from the transmitter, therefore, an inaccuracy of up to one complete pulse occurs at the start of the test. The same situation repeats at the end of the known distance. This causes inaccuracies in the overall measurement up to plus / minus one pulse.

Similarly, when the known distance is large, the number of pulses counted over the distance traveled is also very large. An inaccuracy of plus or minus one pulse may not be severe in all cases. For example, if the W coefficient is 2,500 and the distance tested is 1 kilometer, the measurement inaccuracy is 0.04%. In contrast, the measurement inaccuracy at a test distance of 20 meters is 2%.

To determine the W-coefficient of commercially available vehicles, two ways of providing a known distance are typically used - either a rolling taxiway on which any distance can be simulated (but which itself requires calibration as such), or the distance traveled. The rolling rolling track is simple to use, but expensive, and calibrating is not easy. In the case of the use of a measured length track, the only required and necessary calibration is to measure its length. The vehicle calibrated on the trajectory of the measured length can then be used to calibrate the rolling taxiway.

Although it is preferable to use a long run to achieve measurement accuracy in a simple manner, the appropriate long runway space and the corresponding time necessary to travel the full length of such runway are usually not available for this purpose. Accordingly, there is a need to use a shorter path and to improve the method of fc fc fc fc fc fc

determining the number of pulses generated from the transmitter to indicate speed / distance during taxiing along a path of the appropriate length. At present, it is therefore customary to use a 20-meter track to install the sensing field and calibrate the tachograph.

EEC Council Directive 3821/85 requires a vehicle equipped with a tachograph to be calibrated to within ± 1%. To achieve this accuracy, the accuracy of the calibration system is required to be slightly higher, say ± 0.3%. Thus, when a rolling taxiway is used, the rolling taxiway must have an accuracy of ± 0.3%. For this purpose, a calibration system designed to calibrate such a rolling taxiway must have an even higher accuracy, say + 0.05%. Since a vehicle is used to calibrate the rolling track, it must first be calibrated to an accuracy of + 0.05%.

Critical factors for calibrating a vehicle while crossing the measured distance are:

1. Measurement of path length;

2. Relation of pulses generated from the transmitter to indicate speed / distance relative to the exact beginning and end of the measured distance; and

3. Determining the exact number of pulses generated from the transmitter during crossing the measured distance, including the fractions of the pulses occurring at the beginning and at the end of the path.

Although the length of the runway can be measured using standard means / locations at which the vehicle •

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it overcomes the beginning and the end to millimeters. track, identify with accuracy SUMMARY OF THE INVENTION View from above mentioned according to the present of the invention proposes a method calibration measuring equipment vehicle speed or distance, that is equipped

a pulse generator for generating transmission pulses in response to a vehicle travel distance, said transmission pulses having a frequency that is related to the vehicle speed or distance traveled, the method comprising the steps of:

providing a path having a predetermined length between a start signal and a target signal light;

actuating the vehicle between the start and destination signal lights and counting the number of complete transmit pulses produced by the pulse generator;

determining a pulse width fraction that occurs between the initial signaling signal and the first complete transmit pulse, and determining a pulse width fraction that occurs between the last complete transmit pulse and the target signaling signal; and determining the number of complete transmit pulses and transmit pulse fractions occurring while the vehicle is moving.

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9999 99 4 »44 * 4 ·· 44 between said signaling lights, and using the obtained information, together with a known path length, to determine the calibration coefficient of the vehicle speed / distance measuring device.

Each fraction of the pulse width can be accurately determined by measuring the time interval between the signal light and the nearest next edge of the pulse and then comparing this time interval to the duration of the complete pulse. If, for example, a pulse rising edge is used as a reference point, then the time interval A can be measured between the initial signaling signal and the first subsequent pulse rising edge. In addition, the time interval C between the last rising edge of the pulse and the target signal light can also be measured. If these time intervals are expressed as the fractions of the respective time intervals B and D measured between two consecutive leading edges of the pulses at the beginning and at the end of the path (ie as the pulse width fraction), then these fractions represent the respective pulse fractions to be added to the counted number of complete impulses.

Based on the mutual relation of the time intervals A to B at the beginning of the track, and the mutual relation of the time intervals B to D at the end of the track, the permissible tolerance for any change in vehicle speed between the beginning and the end of this track can be determined. However, the vehicle will preferably travel along the track at a constant, constant speed, which means that B is equal to D.

The present invention can be used, for example, in combination with a relatively short 20 meter path.

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- 7 - 0,000 · 0 · * 0 0 0 0000 00 ·· «0 0 0 0« • 0 0 0 0 0000 00 00 Time taxiing vehicles along the track between two signaling lights can be notified signal, which is

caused by actuation of the switch when the reference point on the vehicle passes through the relevant signal light. This arrangement can be used to provide a time-controlled interval between the initial signal light and the target signal light during which complete (or integral) pulses are counted. Said switch may be a mechanical type switch, for example an antenna or a rod-shaped element which, when passing over a signal light, strikes the edge of a V-shaped notch. In addition, the switch may also be actuated by pressure when one of the vehicle tires passes through the pressure mat, or the switch may be an optical switch arranged on the vehicle, which is actuated when the respective part of the vehicle is detected in the position of the signaling light.

The present invention may be used in combination with a tachograph that indicates the speed of the vehicle and at the same time records information relating to the distance covered, including the speed and distance of the vehicle traveled. (For vehicles that must be equipped with tachographs, such tachographs are usually used only as a means of indicating speed. However, the present invention is not limited to using tachographs as speed measuring and indicating instruments.) It is usually necessary to calibrate the tachograph for each particular vehicle model as a result of the type of gearboxes, rear axles and tires used. For example, assuming that a transmitter generates 8,000 pulses for each kilometer per kilometer. the distance traveled must then be increased by 1/8 000 km for each pulse on the odometer. In practical terms, the distance measuring instrument will require pulses to represent increments of 0.1 or 0.01 km. The number of pulses from the speed / distance indicating transmitter is counted as long as these pulses represent a distance greater than the incremental coefficient of the distance measuring instrument. The distance meter then adds the corresponding increments, and the incremented distance given by the distance meter is subtracted from the detected values of the speed / distance pulse counter. This allows the display of the odometer to indicate the correct distance traveled by the vehicle for the appropriate number of pulses generated for a specific gearbox / axle / tire design. The tachograph is provided with means for adjusting the corresponding calibration coefficient, such as switches, electronic memory and the like. The microprocessor is programmed to respond in response to the aforementioned setting so that the distance measurement device setting allows the increments to be added accurately in relation to the vehicle traveled the distance traveled.

While the transmitter-generated pulses are primarily read for distance measurement, the frequency at which the pulses are generated by the speed / distance transmitter mounted on the gearbox is proportional to the speed of the vehicle. In addition to the above, the microprocessor can also be programmed to respond in response to this frequency of generation of fc Q-Q-7 -7-f-fc fcfc ·· · ν fcfc at at ·> »·>

pulses and a calibration coefficient so as to provide an output signal that is supplied to an electronic display unit for indicating vehicle speed.

Since the technical procedures for recording information via the tachograph are well known to those familiar with the prior art, these will not be described in further detail. However, it must be understood that the present invention can only be applied to such arrangements that are capable of providing means for accurately calibrating the odometer and speed indicator (electronic display unit) on the tachograph.

One way to measure pulse fractions occurring at intervals beyond (a) during crossing the initial signal light and before reaching the first leading edge of the next pulse, and after (b) between the last full pulse and the target signal light, is to count faster pulses at these intervals. . These pulses are generated by a second pulse generator with a much higher frequency compared to the frequency of the transmission pulses generated by the vehicle. For example, pulses generated by an oscillator or suitably divided clock pulses having a fixed frequency may be used for counting increment by the counter. (Fast pulses will be referred to as clock pulses for purposes of the invention, although these pulses may be generated by any suitable means usable for that purpose and, in addition, may or may not be divided.) the edge of each transmission pulse and, in addition, during the passage of the vehicle through the start and finish

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444 44 • • * 4 4 4 • 444 4 * 44 4444 signal light (for example, when the switch is actuated by hitting the antenna on a V-slot notch when the corresponding signal light is reached). However, it is more preferred that the tachograph microprocessor is programmed to determine a counted number of transmit pulses, which represents the number of complete pulses generated by the pulse transmitter (or first pulse generator) during the movement of the vehicle between the respective signal lights. In addition, it is further programmed to determine the respective transmit pulse widths in the areas of the start and destination signal lights, for example by subtracting the counted clock counts on the leading edge of the pulse from the counted clock counts on the next leading edge (i.e. If the vehicle is moving at a substantially constant speed over, for example, a comparatively short path, it can be reasonably assumed that the pulse widths on both signal lights are the same. In the latter case, it is only necessary to determine a single width of the complete transmission pulses. Each fraction of transmit pulses occurring in the interval after crossing the initial signal light and immediately before reaching the target signal light can also be calculated from the counted number of clock pulses. This calculation can be performed by a microprocessor, which is also programmed to add fractions of complete (transmit) pulses to the counted number of complete (transmit) pulses, and then compare this number with a known distance between the start and destination signal lights to calculate the conversion; AAAAA AAA AA AAA AAA

ΑΑΑΑ AA A · AAA · «Α AA calibration coefficient. The determined calibration coefficient can then be manually adjusted on the tachograph or stored in the microprocessor memory.

Generally speaking, the on-board microprocessor located on the instrument panel can be programmed such that the number of full transmit pulses and their individual fractions is determined in the window between the switch signals representing the positions of the respective, start and target signal lights. The distance between these signaling signals is stored as information that is accessible by the microprocessor. This information provides relevant information that can be processed to accurately determine the calibration coefficient. The calibration coefficient thus determined may be stored in the microprocessor memory for the purpose of converting transmit pulses to distance and / or speed information that is recorded by the tachograph during vehicle operation in a standard manner.

Alternatively, an external signal processing circuitry may be provided to which pulses from the speed / distance indicating transmitter and pulses from switches are signaled as input pulses to indicate when the vehicle passes the initial and target signal lights. The external circuitry may include counter means for counting integral pulses between the start and destination signal lights; timing and / or counter means (for counting fast pulses) for timing the intervals between the initial signaling signal and the first pulse leading edge, and between the last pulse leading edge and the target signaling light, and a computing system for performing • I 0

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0000 00 (0) The calculation of the exact number of integral transmit pulses and fractions of these transmit pulses to determine the calibration coefficient. This coefficient may be in the form of an output that allows adjustments to be made. calibrating the tachograph as described above.

In accordance with claim 4, instead of measuring the fraction widths of the pulses occurring in the areas of the signal lights, a measurement of the distance traveled is performed.

The path length fractions can be read or added to a known path length in a simple way to accurately determine the distance traveled by the vehicle during an interval x of complete or integral pulses generated by (for example) a gearbox transmitter. The value of x will vary depending on the vehicle type and pulse generator, and with each change in path length. This may be, for example, the number of pulses corresponding to the distance between the signaling lights or the number of pulses covering this distance. Typically, the first fraction of the transmit pulse will occur after the initial signal light is overcome, while the second fraction of the transmit pulse will occur immediately before the target signal light is overcome. This will become more apparent in conjunction with the detailed description of the exemplary embodiments set forth below.

Said path length fractions may also be used to determine their corresponding transmit pulse fractions, which are then added to the counted number of complete • ftft * * ftftftft ft ftft · ftft ftftft ··· ftft ·· ftftftft ftftftft ftft ·· ftftftft ftft ftft of transmit pulses to achieve a value that is compared to a known distance between the signal lights to determine the calibration coefficient of the vehicle speed / distance measuring device.

The proposed method can be performed by using a bar code and a bar code reader to determine the respective fractions of path lengths. For example, the vehicle may be provided with a bar code extending in the normal direction of its travel path (this bar code may have a permanent part of the vehicle). The barcode reader is then provided in each position in which the signal light is located so that it is capable of reading the barcode while the vehicle is passing over the barcode reader. In the position of the initial signal light, the size of the barcode range read before reaching the first leading edge of the transmitted pulse is proportional to the distance (or fraction of the path length) to be subtracted from the total distance to determine the relationship between the counted counts and the vehicle expensive. The same situation occurs when the target signal light is reached except that the bar code size subtracted between the last full transmit pulse and the target signal light is used to determine the desired path length fraction to be subtracted from the total path length. The two path length fractions can be subtracted from the total path length for the purpose of detecting the vehicle traveled distance, which is then compared to the counted number of integral pulses, resulting in a calibration coefficient. (A hasty method may be more suitable for measuring the distance traveled by the vehicle at an interval immediately after crossing the target signal and up to the point where the leading edge occurs. • I 4 4 4 * 4 φ * • 4 · 4 »4 · 4 * 4 4> 4

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4444 44 4 * 4444 44 44 of the next pulse generated by the transmitter. In this case, the correction distance may be added to the total path length and to the total counted pulses, which may be defined by the transmit pulse spanning the target signal area.) The onboard microprocessor that is part of the tachograph may be used to calculate and store the calibration coefficient for the relevant vehicle type into memory.

Alternatively, path length fractions can be converted to pulse fractions occurring in the region of the start and finish signal lights in a manner similar to the methods described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be explained in more detail by means of specific exemplary embodiments thereof in combination with the accompanying drawing, in which:

FIG. 1 is a schematic representation of vehicle positions on a track and a corresponding pulse diagram relating to a first embodiment of the present invention;

FIG. 2 is a block diagram of the measuring means; and Figures 3 and 3A schematically illustrate further embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

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Referring to the accompanying drawings, there is shown a vehicle 1 which is provided with a pulse generator 2 for generating transmit pulses stored on its transmission housing 3 and which is located at the beginning of a track 4 having a precisely predetermined length (e.g. 20 meters). The length of this path can be measured using any suitable and accurate measuring means.

satisfying the above purposes

The initial signal light 5 and the target signal light 6 designate and define the beginning and end of the measured path length. These signal lights are shown only schematically, since these signal lights may in fact exhibit some form of switch actuated by passing the reference point arranged on the vehicle 1 over the respective signal light 5 or 6. By these signal lights 5 and 6 may be, for example, V-shaped notches which are spaced apart from one another on the track and whose edge edges represent a precisely defined beginning and end of the measured track section. The antenna or rod-shaped contact element, temporarily attached to the vehicle, may be arranged such that it gradually strikes the V-shaped pads as the vehicle travels, causing the switch contacts to close, generating start and end signals a window in which the pulses emitted by the pulse generator are counted

2. Possible mounting of the switch on the vehicle voids the need for an external control system, since the corresponding measurements can be made directly on the dashboard of the vehicle.

In addition, any other form of switch may be used. An alternative type of mechanical switch can be • φ φ «· · φ · φ φ φ φ φ φ

ΦΦ Μ Φ φφ ΦΦ for example, a pressure belt (or mat) that is compressed by the vehicle's tire and thus controls the switch contacts. Alternatively, it is possible to use optical arrangements whose operation consists, for example, in that the vehicle reference point captures the radiated beams emitted at the position of the signaling signal, which results in the generation of a corresponding pulse. Alternatively, a reflecting mirror may be provided behind the signal signal to reflect the radiated beams emitted from the vehicle, the reflected beam being detected by means of a photocell to provide a pulse signal. The nature and nature of the switch is not relevant to the foregoing insofar as it is capable of providing accurate indication of the vehicle's entry into the track (in the position of the initial signaling signal) and the output of that vehicle (in the position of the target signaling signal).

The signal processing means 7 used to count the number of integral pulses and to determine the pulse width fractions at the start and destination signal lights may be incorporated into the microprocessor or may be arranged externally to the tachograph. In both cases, the microprocessor can be used to control the control of the signal processing process in which time intervals representing pulse width fractions on the start and end signal lights are precisely determined, and these time intervals are then effectively associated with the number of integral pulses resulting in addition both pulse fractions to the counted number of complete pulses, and thus absolutely accurate determination of how many pulses and what fraction of these pulses are generated while the vehicle is traveling along the path between the start and finish signal lights.

It is advantageous if it is possible to ensure that the vehicle • 4 • * 4 • · 4 A • * 4 • AAA «44 ·

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During its passage over the measured length it moved along the track at a constant speed. Generally speaking, the transmit pulses generated by the pulse generator are counted in the window between the start and destination signal lights. Referring to Fig. 1, a characteristic pulse diagram is shown in which the start of a transmit pulse E1 is indicated before reaching the position at which the initial signal light is located, with the result that only the pulse fraction is located behind that position. Similarly, the beginning of the last transmit pulse EE is also indicated immediately before reaching the target signaling signal and is incomplete since the vehicle passes over said signaling signal. In the exemplary embodiment shown, the generated pulses are rectangular transmission pulses. The beginning of the transmit pulse is the rising edge of the pulse, and the end of the pulse overlaps and coincides with the rising edge of the next subsequent transmit pulse. At the transmit pulse width B, the fraction A of the first pulse occurs only at the interval of the vehicle crossing the initial signal light. At the end of the track to be tracked, the transmit pulse width D (if the vehicle speed is constant over the entire path) is the same as the transmit pulse width B, except that the fraction C of the last pulse only occurs before the target signal light is reached. The durations represented by the magnitude of the intervals A and C can be accurately measured. This measurement can be performed by generating pulses at a much higher frequency compared to the frequency of the transmitting pulses and counting the number of fast or clock pulses generated during the monitored time intervals. The counted number of clock pulses is stored, for example, when each rising edge of the transmission pulse occurs.

• · · · · · · * * * * * * * * * * * * * * * * * * *

In the exemplary embodiment shown (in which the clock pulses are only schematically indicated), a counting number of clock pulses of 1,053 is present at the leading edge of the pulse that occurs just prior to passing the vehicle through the initial signal light 5. This counted number of clock pulses (1,053) is also memorized when the vehicle crosses the initial signal light. This can be accomplished by triggering a switch that is actuated when the antenna mounted on the vehicle encounters a V-shaped notch. The next counted number of clock pulses (2,053) to be stored is the number of pulses. , which occurs when the next, rising edge of the transmit pulse is reached. In this state, the pulse width at the initial signaling position is equal to a difference of 2,053 - 1,053 = 1,000. The fraction A of the width of the first pulse occurring in the interval after reaching the initial signaling signal and immediately before reaching the leading edge of the next transmit pulse (p2) equals 2,053-1,353 = 700. Accordingly, the A / B ratio is simply 700/1,000 or 7/10 of the transmit pulse width. Essentially the same procedure applies to the target signaling area 6 and will therefore be readily apparent without any further explanation of this procedure being necessary.

The number of complete transmit pulses occurring between the start and destination signal lights can be derived from the counted number of pulses, which represents the occurrence of leading edges of the pulses after the vehicle has crossed the initial signal light and immediately before the vehicle exceeds the target signal light. Thus, the duration of fcfc of fcfc of fcfc of fcfc of fcfc of fcfc of fcfc of one pulse width (B or D) is exactly known. Therefore, the ratios A / B and C / D represent the fraction of the pulses occurring at the beginning and at the end of the measured path. These ratios are added to the total number of integral pulses that are counted as they pass over the length of the measured path, resulting in a non-integer value of the number of pulses generated over the length of the measured path. In the case of using a 20 meter track, this number can be multiplied, for example, by 50, resulting in a number of pulses per kilometer.

A suitable fast or clock pulse can be generated by an oscillator that, for example, for illustrative purposes only, emits a corresponding pulse every 10 microseconds. This oscillator may be part of a circuit board electrical circuitry, which in turn is part of the tachograph. The microprocessor may further cooperate with a counter (which may be, for example, a 16-bit computer) whose values are incremented by the increment represented by each clock pulse, and the counted number of clock pulses are recorded for each rising (or rear) edge of the pulse. Preferably, the on-board microprocessor of the vehicle serves to calculate a calibration coefficient, which is then stored and subsequently used to convert the frequency of the transmit pulses to a speed indication and to index the distance measuring instrument used to measure the distance traveled by the vehicle.

In the embodiment shown in Fig. 3, the vehicle is provided with a barcode 15. Usually, the vehicle is provided with only a single barcode, but in the illustrated embodiment, for the purpose of illustrating the barcode positions at times t1, t2, and

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444 t4, t5 vehicle provided with two barcodes in the area of the initial signaling signal and two barcodes in the area of the target signaling signal. The barcode scanner 16 has its read window aligned with the start signal light 5, while the second barcode scanner 17 has its read window aligned with the target signal light 6. The leading edge of each transmit pulse indexes the counter by counting the number of all complete transmit pulses that occur in the interval t5-tl, ie within the measured distance. According to the preceding embodiment, the individual fractions of transmit pulses occurring in the interval t2-t1 immediately after the initial signaling signal 5 is overcome and in the interval t5-t4 immediately before the target signaling signal 6 is overcome are added to the number of integral pulses. In contrast, in this embodiment only the measurement of equivalent distances or fractions of path length is required for this purpose.

Three possible methods for determining the respective fractions will be described below (however, these methods are not exclusive since any other approaches may be accepted by those skilled in the art for this purpose without departing from the basic concept of the present invention).

(1) After the initial signaling signal 5 has been reached, a circuit-wiring circuitry (not shown) coupled to the barcode scanner 16 is actuated via the leading edge of the bar-shaped bar code 15 at time t1. Again, this assembly is lowered by the leading edge of the first integral pulse p2 (immediately after the leading edge of the bar-shaped bar code 15 has overcome the initial signal light).

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Since the length of the barcode strip 15 is precisely known, as well as the relative relationship between the position of the barcode 15 and its length, the distance A can be derived. For example, the size of the barcode range read in interval tl-t2 corresponds to a certain digital number and this number represents the corresponding distance A of the measured barcode strip length 15. This distance A can then be subtracted from the known distance d, representing the distance between the start and destination signal lights (since the leading edge origin of the first integral pulse p2 occurs at time t2 after the vehicle has traveled distance A). In a similar manner, the circuitry not shown, coupled to the barcode scanner 17, is triggered and actuated by the leading edge of the barcode strip 15 at time t5 and then again by the leading edge of the first integral pulse (after the leading edge of the barcode strip 15 has overcome target signal light). The described activity enables the calculation of distance G, which is also derived, as in the previous case, from distance d. Since it is possible to calculate the number N of the integral pulses occurring between the start and destination signal lights, this implies that d - (A + G) represents the distance corresponding to the total number of N integral pulses. On this basis, it is then possible to determine the calibration coefficient.

Instead of distance G, it is also possible to determine the distance F. In this case, the bar code shows the initial signal marker by an distance F and this distance must be added to the path length (ie d - A + F represents the distance traveled during counting). this count includes one extra pulse).

0 0 * 0 · «·« · * 000 0 0 0 0 0 0 · 0 0

0 0 0 0 0 0 0 0 00 ·· 00 00 0000 00 00

Although a commonly known barcode may be used for this purpose, the barcode expression may include any type of code or coding having a relation between position and length.

(2) The width L 'of the first integral pulse may be measured after crossing the target signal light and this width may be related to the distance from which the distance G or distance F is subtracted to determine the appropriate path length fraction. 3A.

(3) In this alternative embodiment, the barcode strip 15 is modified such that its reference point is in the center thereof, which means that the reference point triggers and actuates the barcode reader when the barcode is in position signal lights. In this way, the measured magnitude of the barcode range located after (or upstream) the centrally arranged reference point can be derived from the measured path length as in the previous case.

In the exemplary embodiment shown in Fig. 3, the first leading edge of the full pulse occurs after the initial signal light is overcome, while the last leading edge of the full pulse occurs immediately before the target signal light. In this state, both fractions of the path length must be derived from the known path length before comparing this distance to the number of integral pulses. However, it is also permissible to determine the fractions of path lengths occurring before the initial signaling signal and after the target signaling signal has been overcome,

AND

0 000 f, • 0 000, which fractions of the path length determined are then added to the known path length in order to determine the distance to be compared with the number of integral pulses. In the latter cases, the fractions of complete or integral pulses are spread over signal lights and the counted counts are different for each.

However, for various reasons, it may be more convenient to place the barcodes on the signal lights and mount the barcodes on the vehicle. This arrangement has the advantage of requiring the use of only one barcode reader and, moreover, allows the barcode information from the barcode reader to be fed directly to the electrical circuitry located on the dashboard of the vehicle and processed by the tachograph microprocessor.

The use of the barcode as such is not inevitable, since essentially the same information can be provided by other types of coding or raster grids or point structures.

Advantages of at least preferred embodiments of the present invention are that the test personnel can only drive the vehicle on a short test track. The method used is accurate and adequately sufficient to calibrate the rolling track. The described arrangement is applicable to all types of speed / distance indicating transmitters equipped with an electronic output, including those transmitters that are not operating at very low speeds. The on-board microprocessor is able to easily determine and record the calibration coefficient of the vehicle in memory. This arrangement can, in addition to • 4 4 • · v 4 444 · ·

4

this can be easily replaced or updated for vehicles (or for the same vehicle, if equipped with a tachograph) with regard, for example, to gearboxes, or to tire dimensions, axle-to-axle transmission.

different ratio or

Represented by:

Dr. Milos Všetečka v.r

JUDr. Milos Všetečka - 25 -, *? * jUpráyphe party attorney

120 00 Prague 2, Halkova 2

Claims (18)

PATENT CLAIMS A method of calibrating a vehicle speed or distance measuring device (1) having a pulse generator (2) for generating transmission pulses (p) in response to a distance traveled by a vehicle traveled, said transmission pulses (p) having a frequency, which is related to the speed of the vehicle (1) or the distance traveled by it, the method comprising the steps; providing a track (4) having a predetermined length between the start and destination signal lights (5, 6); and driving the vehicle (1) between the start and destination signal lights (5, 6) and counting the number of complete transmit pulses (p) produced by the pulse generator (2); characterized in that the method further comprises the steps of: determining each fraction (A) of the pulse width (B) that occurs between the initial signaling signal (5) and the first complete transmit pulse (p1), and determining each fraction (C) of the pulse width (D) that occurs between the last complete a transmit pulse (pf) and a target signal light (6); and determining the number of complete transmit pulses (p) and transmit pulse fractions (A, C) occurring during taxiing. 4 · «4 4 • ···» 4 ···· 44 · · · 4 · 4 The vehicle (1) between said signal lights (5, 6), and using the information obtained, together with a known path length, to determine the calibration coefficient of the vehicle speed / distance measuring device (1). Method according to claim 1, characterized in that each pulse width fraction (A, C) is determined by counting the pulses generated by a much higher frequency compared to the frequency of the transmitting pulses. Method according to claim 1 or 2, characterized in that the transmission pulse width fraction (A) is measured between the initial signaling signal (5) and the first transmission pulse leading edge, and the transmission pulse width fraction (C) is measured between the last complete signal pulse. transmitting pulse and target signal light (6), and determining ratios (A / B) and (C / D), where (C) and (D) represent the widths of the complete transmit pulse in the region of the respective start and destination signal lights (5, 6); these ratios represent the corresponding fraction of transmit pulses which are added to the counted number of transmit pulses. A method of calibrating a vehicle speed or distance measuring device (1) equipped with a pulse generator (2) for generating transmission pulses (p) in response to a distance traveled by a vehicle traveled, said transmission pulses (p) having a frequency, which is related to the speed of the vehicle (1) or the distance traveled by it, the method comprising the steps of: providing a track (4) having a predetermined length between the start and destination signal lights (5, 6); and • 4 4 4 * · 4 • 4 ······ »» · · 4 4 4 4 4 4 4 4 4 • * f. · ·. · _ »<A Adjust the side of bringing the vehicle (1) into motion between the start and destination signal lights (5, 6) and counting the number of complete transmit pulses produced by the pulse generator (2); characterized in that the method further comprises the steps of: determining each positive or negative fraction of the path length that occurs between the respective signal light and the nearest edge of the transmit pulse, and using these fractions of path length, the number of complete transmit signals, and a predetermined path length to determine the calibration coefficient of the speed / distance measuring device vehicles (1). Method according to claim 4, characterized in that the corresponding transmission pulse fractions (A, C) (p) are determined from said path length fractions, wherein these transmission pulse fractions (A, C) are added to the counted number of complete transmission pulses to provide a value that is compared to a known path length extending between the signal lights (5, 6). Method according to claim 4, characterized in that said path length fractions are added to or subtracted from a known path length to determine the actual distance corresponding to a counted number of complete transmit pulses occurring between the signal lights (5, 6). Method according to claim 5 or 6, characterized in that the magnitude of the barcode range (15) read between the side of the signaling signal (5, 6) and the next edge or edges of the transmit pulse (p) is used to determine fractions path length or transmit pulse width. Method according to any preceding claim, characterized in that the travel time of the vehicle (1) on the path (4) between the signaling lights (5, 6) is signaled by a switch or switches actuated by passing the vehicle reference point (1) over the respective signal light (5, 6). A method according to any preceding claim, characterized in that the switch is mounted on the vehicle (1) and actuated by passing it over the respective signal signal (5, 6). Method according to any of the preceding claims, characterized in that the respective switches are installed on the signal lights (5, 6) and actuated by passing the vehicle (1) over the respective signal lights. A method according to any preceding claim, wherein the switch is a mechanical switch comprising an antenna or a rod-shaped element striking the edge of the V-shaped notch. Method according to one of Claims 1 to 10, characterized in that the switch is actuated by applying pressure during the passage of the vehicle tires over the switch. A method according to any one of claims 1 to 10, characterized in that the switch is an optical switch installed in the system. on a vehicle (1), which is actuated by detecting the respective part of the vehicle (1) on the signaling signal (5, 6). Method according to any one of the preceding claims, characterized in that when used for calibrating a speed measuring device for a particular type of vehicle (1), the transmission ratio of the gearbox or the rear axle transmission, or the dimensional dimensions of the tires, or any combination. Method according to any preceding claim, characterized in that the speed measuring device is, or is part of, a tachograph that indicates the speed of the vehicle and records the distance traveled by the vehicle (1). Method according to claim 15, characterized in that the tachograph comprises an odometer (13), means for providing a calibration adjustment of the odometer, and a microprocessor programmed so that the calibration adjustment allows the odometer (13) to be measured. distance in response to said adjustment so that it can add accurate increments to the vehicle (1) distance traveled. 17. The method of claim 16, wherein the microprocessor is further programmed to respond in response to a transmit pulse frequency to provide an output signal that is applied to an electronic display unit to indicate vehicle speed. 18. The method of claim 1, 4 4 * 4,444 • 4 4444 44 »··· 444».: In. The side that the microprocessor is programmed to count the number of full transmit pulses in the window between the switch signals representing the positions of the start and finish signal lights (5, 6) and so that the timing interval between the initial pulse of the switch and the first rising edge of the transmitter pulse to indicate the speed / distance, as well as the interval between the last pulse of the transmitter and the target signal signal (6).