JP2012026920A - Wheel and axle weight measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily suspect the fluctuation of a span in an early stage, and to easily perform the inspecting and calibrating operation of the span as necessary.SOLUTION: A meter 4 is configured by installing a measurement stand on a road surface, and the weight of the wheel or axle of a test vehicle passing at least once on the measurement stand is measured by an arithmetic circuit 14. The weight of the wheel or axle of the test vehicle is already known. Radio transmitting/receiving circuits 13 and 32 for transmitting the weight of the wheel or axle of the test vehicle measured by the meter 4 by radio from the arithmetic circuit 14 to an arithmetic circuit 30 loaded on the test vehicle are installed in the arithmetic circuits 14 and 30. The arithmetic circuit 30 is provided with a display unit 30b for displaying one or both of the weight of the wheel or axle of the test vehicle transmitted by radio and its average value.

Description

  The present invention relates to a wheel / axle weight measuring system for measuring the wheel weight and axle weight of a vehicle, and more particularly, to a system for checking the span of a measuring instrument constituting the wheel / axle weight measuring system and performing a span calibration operation.

  Conventionally, in a wheel weight measurement system, a weighing table provided with a load sensor is embedded in a road surface, and the wheel weight is measured at a timing when a tire is placed on the weighing table. Specifically, there are those disclosed in Patent Documents 1 and 2. In the technique of Patent Document 1, the length of the weighing platform is set sufficiently longer than the length of the contact surface of the tire in the wheel traveling direction, the weighing platform is supported by a plurality of load cells, and the tire is not in contact with the road surface. The weight of the wheel is measured in the state. In the technique of Patent Document 2, the length of the weighing platform in the traveling direction of the tire is set to be shorter than the length of the contact surface of the tire, and the weight of the wheel is measured while the tire contact surface is always in contact with the road surface.

Japanese Patent Publication No.53-23099 JP-A 63-286724

  The weighing platform of the weight measurement system as shown in Patent Documents 1 and 2 is embedded on the road surface, exposed to direct sunlight in summer, freezing in winter, wind and rain throughout the year, and sometimes submerged. Sometimes. In addition, the temperature difference between day and night is severe even if only one day is seen. Therefore, the surrounding environmental conditions are extremely severe for the load cell provided on the weighing platform.

  The strain generating part 200 of the load cell used in the techniques of Patent Documents 1 and 2 is housed in an airtight chamber 204 surrounded by a metal case 202 as shown in FIG. 9, but outputs a load signal to the outside. It is necessary to take out the wiring for taking in the power supply to the outside of the metal case 202. Therefore, the metal frame 206 for attaching the airtight terminal plate is welded to the metal case 202, and the outer frame 205 of the airtight terminal plate is solder welded to the metal frame 206, and the glass wiring for protecting the airtight terminal plate outer frame is taken out. An airtight terminal board 208 is attached. A waterproof connector 210 for connecting wiring from an external device to the hermetic terminal board 208 is attached to the outside of the metal frame 206 for attaching the hermetic terminal board. In the wiring connection chamber 210 a in the waterproof connector 210, a cable 212 that is an external wiring is connected to the airtight terminal 208 a of the airtight terminal plate 208.

  The waterproof connector 210 is made of metal, and the introduction portion of the cable 212 is sealed by a rubber seal member 214. However, the confidentiality of the wiring connection chamber 210a is not perfect as in the metal case 202, and Ordinary air also enters through gaps inside the wiring cable 212. Since normal air also contains a water vapor component, the resistance value decreases between the signal lines of the hermetic terminal board 208 and the signal lines and the metal case 202, which always need to maintain a high insulation resistance, and the load The signal span is likely to drift. In addition, since the temperature difference around the load cell is extremely large, temperature compensation does not function accurately even in a state where there is no reduction in insulation.

  If there is a difference in the height of the road surface and the surface of the weighing table, especially in the weighing table of Patent Document 2, there is a difference between the height of the road surface and the surface of the weighing table. The load distribution between the surface and the weighing platform changes.

  Because of such usage conditions, it is difficult for the wheel / axle weight measurement system to maintain a stable span for a long period of time and the failure rate is higher than other types of measuring instruments. Therefore, periodic inspections at short intervals are necessary.

  However, span inspection and calibration work has conventionally been required to be performed while the vehicle is stopped, resulting in a large work and a vehicle traffic obstacle.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a wheel / axle weight measuring system that can detect a span variation as easily and as early as possible, and that can easily check and calibrate the span when there is a variation that cannot be overlooked. And

The wheel / axle weight measuring system according to one aspect of the present invention includes at least one weighing instrument having a weighing platform installed on a road surface, and the weight of the wheel or axle of a test vehicle passing at least once on the weighing platform. A load signal measuring device for measuring, and an in-vehicle control device provided in the test vehicle,
I have. A plurality of measuring instruments can be arranged along the traveling direction of the vehicle. Further, the test vehicle can travel a plurality of times on the measuring instrument. In the test vehicle, the weight of the wheel or axle is known. For example, this known weight is the weight of the wheel or axle when an object of known weight is loaded on the test vehicle. The weight of the wheel or axle can be determined for each wheel or axle. Wireless communication means for wirelessly transmitting the weight of the wheel or axle of the test vehicle measured by the measuring instrument from the load signal measuring device to the on-vehicle control device is provided to the load signal measuring device and the on-vehicle control device. Is provided. What is necessary is just to provide a transmission means and a reception means in the load signal measurement apparatus side and the vehicle-mounted control apparatus side. The vehicle-mounted control device includes display means for displaying one or both of the weight of the wheel or axle of the test vehicle transmitted wirelessly and the average value thereof for each measuring instrument and each axle. The average value can be the average of the weights of the wheels or axles obtained multiple times while the test vehicle wheels or axles are passing over the meter, or the test vehicle can be It may be the average value of the weight of the wheel or axle when passing.

  Since the weight of the wheel or axle is known, it is possible to check the variation state of the span for each measuring instrument by observing the weight of the wheel or axle displayed for each measuring instrument on the display means and the average value thereof. In addition, if the weight of a known wheel or axle is displayed on the display means, this inspection can be performed more easily.

  The said display means shall also display the frequency | count of the weight measurement by the said vehicle in the said measuring device. Thereby, it is also possible to know the number of times the test vehicle has passed over the measuring instrument.

  The vehicle-mounted control device can store the weight for each wheel or axle corresponding to the current load of the test vehicle as a span calibration reference value. In this case, when the test vehicle passes over the weighing platform, the load signal measuring device measures the weight value of the test vehicle for each wheel or axle for each measuring instrument. By means of a command signal from the in-vehicle control device, span calibration means is based on the weight measurement value for each wheel or axle of the test vehicle and the reference value for span calibration stored in the in-vehicle control device, The span is calibrated for each measuring instrument. This span calibration means is provided in the load signal measuring device. The span calibration reference value can be transmitted together with the command signal from the in-vehicle control device to the load signal measuring device by the wireless communication means.

  Thus, span calibration can be automatically performed by giving a command from the in-vehicle control device on the test vehicle side.

  As described above, according to the present invention, it is possible to grasp the variation state of the span by the on-vehicle control device of the test vehicle simply by causing the test vehicle to travel on the measuring instrument. Therefore, it is possible to detect the variation of the span easily and early. Moreover, since the span adjustment can be automatically performed by the span calibration means on the load signal measuring device side simply by sending a command from the in-vehicle control device, the span calibration can be easily performed.

It is a block diagram of the wheel and axle weight measurement system of one embodiment of the present invention. It is a figure which shows the change of the output signal of each measuring instrument as a tire passes on the measuring instrument of the wheel and axle weight measuring system of FIG. It is the front view, top view, and side view which show the structure of the 2nd measuring device of the wheel and axle weight measuring system of FIG. It is explanatory drawing of the measurement principle in the 2nd measuring device of the wheel and axle weight measurement system of FIG. It is a block diagram of the vehicle-mounted control apparatus used in the wheel and axle weight measurement system of FIG. It is a figure which shows the flowchart of a part of span inspection process in the wheel and axle weight measurement system of FIG. It is a figure which shows the flowchart following the flowchart of FIG. It is a figure which shows the flowchart of the span calibration process in the wheel and axle weight measurement system of FIG. It is a partial abbreviation longitudinal cross-sectional view of the measuring instrument used for the conventional wheel and axle weight measuring system.

  In the wheel / axle weight measurement system of one embodiment of the present invention, as shown in FIG. 1, it is assumed that a vehicle not shown on the road surface 2 travels in the direction of the arrow. This wheel / axle weight measuring system includes a load signal measuring device and an in-vehicle control device. A first measuring instrument 4 is installed on the road surface 2. A load signal measuring device is provided in the vicinity of the first measuring instrument 4.

  As shown in FIG. 2 (a), the first weighing instrument 4 has a weighing platform 6, and a plurality of, for example, two first weight value measuring means are provided on the lower surface of the weighing platform 6 on the vehicle entry side. For example, the load cell 8a supports, and a plurality of, for example, two first weight value measuring means, for example, the load cell 8b, support the exit side of the vehicle on the lower surface of the weighing platform 6. Two weighing stands 6 are provided along the width direction of the road surface 2 in order to individually measure the weights of two wheels attached to the same shaft of the vehicle. In the case of simultaneously measuring the weight of two wheels attached to one axis of the vehicle by the first measuring instrument 4, one unit having a width dimension on which two wheels in the width direction of the road surface 2 are simultaneously mounted. The weighing platform 6 is used. As shown in FIG. 2A, these weighing platforms 6 have a length dimension L in the traveling direction of the vehicle that is larger than the length L ′ in the traveling direction of the vehicle on the road surface 2 of the tire 9 of the vehicle. ing.

  The output signals of the load cells 8a and 8b are amplified by the amplifier 10, digitally converted by the A / D converter 12, and supplied to the processing means of the load signal measuring device, for example, the arithmetic circuit 14. The arithmetic circuit 14 includes, for example, a CPU, a memory, an input / output circuit, and the like, and includes an operation unit 14a and a display unit 14b. The result of the arithmetic processing in the arithmetic circuit 14 may be transmitted to the in-vehicle control device of the test vehicle by radio communication means, for example, the radio transmission / reception circuit 13 and the antenna 15, and receives data from the in-vehicle control device. , This may be processed.

  A plurality of, for example, two second measuring instruments 16 and 18 are provided at intervals on the road surface 2 away from the first measuring instrument 4 in the traveling direction of the vehicle. The second measuring instruments 16 and 18 have the same structure, and only the second measuring instrument 16 will be described. As shown in FIGS. 3A to 3C, the second measuring instrument 16 is a strain generating body whose length in the traveling direction of the vehicle is L2 or less and whose length in the width direction of the road surface 2 is L2 ′. A plurality of, for example, four load cells 22a, 22b, 22c, and 22d are arranged in the width direction of the road surface 2, and the load cells 22a to 22d are arranged along the traveling direction of the vehicle. A weighing table 24 having a length L2 is arranged. L2 is set to be shorter than the length L ′ of the ground contact surface of the tire 9 in the vehicle traveling direction. Therefore, even when the ground contact surface of the tire 9 is on the weighing table 24, the total load of the tire 9 is divided and applied to the road surface 2 and the weighing table 24 at a certain ratio.

  In addition, the distance between the two is set so that the tire 9 does not exist across the first measuring instrument 4 and the second measuring instrument 16, and the tire straddles between the second measuring instruments 16 and 18. The interval between them is set so that 9 does not exist.

  When individually measuring the weights of two wheels provided on one shaft of the vehicle, the outputs of the load cells 22a and 22b are synthesized for one wheel and the load cells 22c and 22d are used for the other wheel. Synthesize the output of. When the total value of the weights of two axles provided on one shaft is measured as the axle weight, the outputs of the load cells 22a to 22d are combined. The output signals of these load cells 22a to 22d are amplified by the amplifier 10, digitally converted by the A / D converter 12, supplied to the arithmetic circuit 14, and processed by the arithmetic circuit 14.

  Processing of the output signal of the first measuring instrument 4 performed in the arithmetic circuit 14 will be described with reference to FIGS. 2 (a) and 2 (b). The load signal in FIG. 2 is an output signal of the load cells 8a and 8b corresponding to the movement of the tire center position. In addition, although the following description is a case where the weight of one wheel is measured, on the basis of the following description, measuring the weight (axial weight) of two wheels provided on one shaft, It will be obvious to those skilled in the art. The first weighing device 4 can measure in two modes, a dynamic weight measurement mode and a static weight measurement mode.

  In order to measure in both of these modes, the tire 9 is completely on the weighing platform 6, the position p 1 immediately after the contact between the ground contact surface of the tire 9 and the road surface 2 is lost, and the tire that has entered the weighing platform 6. A position p2 that contacts the road surface 2 when 9 moves forward on the weighing platform 6 and further advances is determined on the output signals of the load cells 8a and 8b. When the distance between the positions p1 and p2 is L11, the time during which the tire 9 stays in the L11 section on the weighing platform 6 can be continued for a long time, and the ground contact surface of the tire that next proceeds to the weighing platform 6 touches the weighing platform 6. Before, the length L1 of the weighing platform 6 and the positions p1 and p2 are set so that the tire 9 is separated from L11.

  The positions p1 and p2 are defined as positions where a predetermined condition is established between the ratio of the output signals of the load cells 8a and 8b and a predetermined constant value. That is, assume that the output signal of the load cell 8a is w1, the output signal of the load cell 8b is w2, and these are sampled at the same timing at the time interval T to obtain w1 (k) and w2 (k) as sampling weight measurement values. The ratio Rw is obtained by w1 (k) / w2 (k). Then, w1 (k) at the position p1 is defined as w11 (k), w2 (k) is defined as w21 (k), a predetermined value is defined as w11 (k) / w21 (k) = f1, and the ratio When Rw becomes larger than f1 and then decreases from f1, it is determined that the position p1 has been reached.

  Similarly, w1 (k) at position p2 is set to w12 (k), w2 (k) is set to w22 (k), w22 (k) / w12 (k) = f2, and after position p1 is determined, Rw The time when becomes larger than f2 is the time when the position p2 is reached.

  Thus, if the positions p1 and p2 are defined by the ratio of w1 (k) and w2 (k), these positions are not affected by the size of the wheel weight.

By obtaining w1 (k) and w2 (k) between the positions p1 and p2, the sampling weight value wi of the tire 9 is
wi = w1 (k) + w2 (k)
The weight measurement value W1d of the tire 9 is W1d = Σwi / N, where N is the number of sampling weight values between the positions p1 and p2.
Sought by. Obtaining W1d in this way is called a dynamic gravity measurement mode.

The dynamic weight measurement mode is based on the premise that the vehicle passes smoothly on the weighing platform 6. However, the vehicle may travel such that the vehicle stops while the tire 9 is on the weighing platform 6 or the tire 9 passes over the weighing platform 6 at a very low speed. The sampling time interval T is set at a short time interval of several milliseconds in order to attenuate the noise superimposed on w1 (k) and w2 (k) and to measure Rw with high sensitivity and accuracy. There are many cases. Therefore, in the case described above, ΣWi is a very large value. Therefore, in order to start counting from the time point when the position p1 is detected, a counter operation is started, and a timer T1 that is incremented at every sampling time interval T is provided. When the count value Ts of this timer becomes equal to or greater than a predetermined Nm , Stop the accumulation of wi, as the weight measurement W1s,
W1s = Σwi / Nm
Ask for. Obtaining W1s in this way is called a static weight measurement mode.

  It should be noted that Nm is set to a value that can be sufficiently attenuated by averaging as described above even if a low-frequency noise signal is superimposed on w1 (k) and w2 (k).

  As is clear from the above description, the weight measurement mode in the first measuring instrument 4 is automatically switched according to the traveling speed state of the vehicle.

Processing of the output signals of the second measuring devices 16 and 18 performed in the arithmetic circuit 14 will be described. In the following description, the weight of one wheel is measured, but it is known to those skilled in the art to measure the weight (axial weight) of two wheels provided on one shaft based on the following description. Is self-explanatory. FIG. 4A shows the contact surface of the tire 9, where the contact width of the tire 9 is Ai, the distance that the tire 9 moves at every sampling time interval T is Di, and the load per unit area of the tire 9 is P. When the contact area is S, the total load W of the contact surface of the tire 9 is
W = P * S = P * Σ (Ai * Di)
It is. Assuming that the vehicle speed is V, the distance Di that the tire 9 moves at every sampling time interval T is Di = V * T in FIG.
It is. Since the contact length L ′ of the tire 9 is longer than the length L2 of the weighing platform of the second measuring devices 16 and 18, as described above, the load on the entire tire contact surface is applied to the portion L2 and the road surface 2. Assuming that the portion of the weighing platform length L2 of the second measuring devices 16, 18 receives a load with respect to the load W of the entire ground contact surface of the tire 9, the second measuring devices 16, 18 are The measurement value of the load received from the tire 9, that is, the weight measurement value Wi obtained by sampling the output signals of the second measuring devices 16 and 18, is shown in FIG.
Wi = P * Ai * L2
It is represented by If this is transformed,
P * Ai = Wi / L2
From the above equation for the total load W on the tire contact surface, the equation for the movement distance Di, and the equation for P * Ai, the total load W on the tire contact surface, which is the weight of the tire 9, is
W = P * S = P * Σ (Ai * Di) = Σ (P * Ai * Di) = Σ (P * Ai * V * T)
= Σ [(Wi * V * T) / L2] = (V * T / L2) ΣWi
It is calculated by the following formula. If the output signal of the second measuring devices 16 and 18 is w3, and the weight measurement value obtained by sampling the output signal at each time interval T is w3 (k),
W2d = (V * T / L2) Σw3 (k)
It is expressed. In this measurement, it is possible to accurately measure the weight of the tire 9 only when the vehicle is traveling at a constant speed V. Obtaining W2d in this way is called a dynamic weight measurement mode in the second weighing instrument. .

  In order to calculate W2d as described above, it is necessary to determine the start timing of ΣW3 (k) (positions p3 and p4 shown in FIG. 2B). For p3 and p4, a boundary weight Wf is determined in advance in the direction of load with respect to the output signal w3 (k) of the second weighing device 16 and 18, and after determining the position p2, w3 (k) exceeds wf. The time point is set to p3, and after the position p3 is determined and w3 (k) returns to the zero point, the time point when w3 (k) exceeds wf for the first time is set to p4.

  When the vehicle stops in a state where the tire 9 is present on the second weighing units 16 and 18, or the vehicle advances such that the tire passes on the weighing table at an extremely low speed, the value of Σw3 (k) is Become enormous. Therefore, timer counters T4 and T5 are provided, and when the points p3 or p4 are detected, the counters are counted at T4 and T5 at every sampling time interval T. When the count value exceeds the predetermined values Nm1 and Nm2, the weight measurement value Is stopped, and the dynamic weight measurement by the second weighing units 16 and 18 is stopped.

  Dynamic weight measurement at the second scales 16,18 requires the speed of the vehicle passing through the second scales 16,18. Further, as will be described later, the speed at which the vehicle passes through the second measuring instrument 4 is used in order to switch between the measurement by the first measuring instrument 4 and the measurement by the second measuring instruments 16 and 18. For this purpose, the arithmetic circuit 14 performs these speed measurements.

First, the detection of the velocity V1 passing over the first measuring instrument 4 will be described. In the first weighing device 4, when the load cells 8a and 8b support the weighing table 6, the points qa and qb are shown in FIG. 2A, and the distance between the points qa and qb is A. The distance A1 between the position q1 corresponding to the position p1 on the output signal of the load cell 8a and the point qa is approximated when the output signals of the load cells 8a and 8b at the points qa and qb are peak and equal. By using f1 described above, approximately A1≈ (1 / f1) * A
Sought by. Similarly, the distance A2 between the position q2 and the point qb corresponding to the position p2 on the output signal of the load cell 8b is also approximately obtained from f2 and A. Therefore, by setting the distance A between the load cells 8a and 8b, and f1 and f2 in the arithmetic circuit 14, L11 (distance between the positions p1 and p2) shown in FIG. 2B is expressed by L11 = A− (A1 + A2). Calculate automatically. Then, when the count at the timer counter T1 starts from the position p1 and stops at the position p2, and the count value C1 is obtained, the vehicle speed V1 is
V1 = L11 / C1
Is calculated by

The detection of the velocity V3 passing over the second measuring instrument 16 will be described. As the speed V3, the speed at which the vehicle passes from the center q0 of the weighing platform 6 of the first weighing instrument 4 to the input end q3 of the second weighing instrument 16 is used. This is because it is unlikely that the speed will change rapidly immediately before the tire 9 is placed on the weighing platform of the second weighing instrument 16. When the tire 9 reaches the point q0, the output signals w1 (k) and w2 (k) of the load cells 8a and 8b become equal. Therefore, the time when w1 (k) ≦ w2 (k) is first established is defined as q0 point. Further, the time when the tire 9 reaches the input end q3 of the second measuring instrument 16 substantially coincides with the position p3. Therefore, the timer counter T3 starts counting from the position p0, and V3 is set to V3 = V3 = V3 using the count value C3 when the position p3 is reached and the distance L31 between q0 and q3 set in advance. L31 / (C3 * T)
Detect as. T is the sampling time interval described above.

The detection of the velocity V4 passing over the second measuring instrument 16 will be described. The timer counter T3 continues counting until the position P4 is detected. If the distance L41 between q3 and q4 set in advance and the count value at the position P4 is C4, V4 is
V4 = L41 / [(C4-C3) * T]
Can be detected.

  There is a case where the vehicle stops or becomes close to the first measuring instrument 4 or is slow or fast.

  When the vehicle is stopped or close to it, rather than detecting the speed of the vehicle, the time that the vehicle stays on the first weighing platform 6 is detected, and if the stay time exceeds Nm * T described above, The weight measurement value W1s in the static weight measurement mode described above is set as the wheel weight measurement value. The weight measurement value W1s in the static weight measurement mode indicates that the vehicle is almost stopped and the amplitude of various noise signals included in the output signals of the first and second load cells 8a and 8b is basically small. Even if there is a noise signal, the noise signal can be smoothed by a sufficiently long sampling measurement time (Nm * T), so that it is not necessary to use a weight measurement value by the second measuring instruments 16 and 18.

  When the speed of the vehicle is slow relative to the first measuring instrument 4, even if the vehicle is running, if the vehicle is running at a low speed, the tire 9 is not in contact with the road surface 2 in the first measuring instrument 4. Since a certain amount of weight measurement time can be taken, a good weight measurement value W1d can be obtained. Moreover, even if shifting is performed during measurement, since one sampling weight measurement value represents the load of the tire 9, no error occurs in the measurement principle.

  Further, when the vehicle speed is higher than that of the first measuring instrument 4, the output signal of the load cells 8a and 8b of the first measuring instrument 4 includes an error component and an impact load due to a low-frequency noise signal generated by the spring of the vehicle. However, when the vehicle speed is high as described above, the measurement time (time to pass from position p1 to p2) is shortened and the number of samplings is reduced, so that the noise smoothing processing capability is low. Become. Accordingly, if only the weight measurement value of the first weighing device 4 is used, the error becomes large. In addition to the weight measurement value of the first weighing device 4, the weight measurement value W2d of the second weighing device 16, 18 is obtained. Are also used to obtain gravimetric measurements.

  As the speed of the vehicle increases, the amplitude of random noise and vibration noise gradually increases, and when the speed of the vehicle is low, the high accuracy characteristic of the first measuring instrument 4 is lost. It is also possible to use only 16, 18 weight measurements. However, even when the speed of the vehicle is high, the first measuring instrument 4 performs measurement in a state where the tire 9 is not in contact with the road surface 2, and thus is more accurate than the second measuring instruments 16 and 18. In some cases, weight measurement is performed on the basis of the first and second measuring instruments 4, 16, and 18 in this embodiment.

  When using the weight measurements of the first and second scales 4, 16, 18, the error can be offset by determining the average value of each weight measurement. As for the low-frequency noise signal, as the number of measuring instruments increases, the positive and negative amplitudes at various phase points of the periodic noise signal can be added, so that the attenuation of the noise signal can be increased. The standard deviation of the random noise signal can be reduced as the number of measuring instruments increases.

  The vehicle-mounted control device is mounted on a test vehicle that passes over the first weighing instrument 4 and the second weighing instruments 16 and 18 described above. As shown in FIG. 5, the in-vehicle control device includes an arithmetic circuit 30, and the arithmetic circuit 30 includes, for example, a CPU, a memory, an input / output circuit, and the like, and includes an operation unit 30a and a display unit 30b. The arithmetic circuit 30 includes wireless transmission / reception means, for example, a wireless transmission / reception circuit 32 and an antenna 34, and the data transmitted via the wireless transmission / reception circuit 13 and the antenna 15 of the load signal measuring device is transmitted to the antenna 34 and the wireless transmission / reception circuit 32. And process this data. In addition, the instruction determined by the operation with the operation unit 30 a is transmitted to the load signal measuring device by the wireless transmission / reception circuit 32 and the antenna 34.

  In the above description, in the description of the sampling measurement weight values w1 (k), w2 (k), and wi, the span and the zero point are ignored, but the first to third measuring devices 4, 16, and 18 are actually used. In the case of measuring the weight of the wheel / axle, the zero point and the span must be taken into consideration, and the span may fluctuate as described in the section of the prior art. Therefore, in this wheel / axle weight measuring system, the span check and span adjustment of the first to third measuring instruments 4, 16, 18 are performed as follows. In the following description, the case of measuring the weight of each axle of the vehicle will be described.

  In the load signal measuring device, the digital load signal of the first weighing unit 4 output from the A / D converter 12 is Wa1 (the output of the load cells 8a and 8b is sampled and added), and the second weighing unit 16 is added. The digital load signal of Wa2 (sampled and added to the outputs of the load cells 22a to 22d), and the digital load signal of the third measuring instrument 18 to Wa3 (sampled and added to the outputs of the load cells 24a to 24d) And Further, when measuring the axle weight of the vehicle, these Wa1 to Wa3 are obtained after it is determined that the tire is on the first to third weighing devices 4, 16, and 18, as described above. Shall be. When the first load balancer 4, 16, 18 is in an unloaded state during span adjustment during installation of the first to third scales 4, 16, 18, the initial load operation point The digital load signals from the first to third weighing devices 4, 16, and 18 output from the A / D conversion unit 12 are transferred to the initial load registers Wi1, Wi2, and Wi3 for each weighing device provided in the arithmetic circuit 14. Remembered.

The stored values of the initial load registers Wi1 to Wi3 are also represented by Wi1 to Wi3, and the first to third measuring instruments 4, which are adjusted and determined by applying a load having a known weight, such as a weight, to the weighing platforms 4, 16, and 18, Assuming that the span coefficients of 16, 18 are k1, k2, k3, the sampling weight measurement values Wn1 to Wn3 of the first to third measuring devices 4, 16, 18 are
Wn1 = k1. (Wa1-Wi1)
Wn2 = k2 · (Wa2-Wi2)
Wn3 = k3 · (Wa3-Wi3)
It is expressed.

  A predetermined zero determination level Wzt is set for the sampling measurement weight value Wn1 obtained while using the first weighing instrument 4, and a U-stage shift register is provided in the arithmetic circuit 14 for the sampling weight value Wn1. The latest U sampling weight values are always stored, and if all U weights are less than or equal to Wzt, these are the sampling weight measurement values when the first measuring instrument 4 is unloaded. Is automatically stored in the zero point storage register Wz1 provided in the arithmetic circuit 14 as the zero point weight value. Similarly for the second and third measuring instruments 16 and 18, the zero point weight value is stored in the zero point storage registers Wz 2 and Wz 3 provided in the arithmetic circuit 14.

When the stored values of these zero point storage registers Wz1 to Wz3 are represented by Wz1 to Wz3, the respective sampling weight measurement values Wn1 to Wn3 are
Wn1 = k1. (Wa1-Wi1) -Wz1
Wn2 = k2 · (Wa2−Wi2) −Wz2
Wn3 = k3. (Wa3-Wi3) -Wz3
By this, a formula for calculating a weight measurement value corresponding to zero adjustment is obtained.

  These sampled weight measurement values Wn1 to Wn3 have a higher resolution for the same load signal than the weight display value displayed on the display 14b. For example, if the first to third measuring instruments 4, 16, 18 are measuring instruments having a rated weight of 20t and a minimum display value of 10kg, the resolution of the weight measurement value is set to four times 8000 counts and the weight measurement value is displayed. In some cases, the display weight value is converted to 1/4.

  The span inspection and calibration in the state where this wheel / axle weight measurement system is normally used will be described. Assume that the test vehicle to be used has three axes, and the wheel / axle weight measurement system measures the axle weight as described above. Prepare to apply a known load to the axle of the test vehicle in advance. A load is loaded on the loading platform of the test vehicle and fixed so that the loading position does not change. Measure the axle weights WS1, WS2 and WS3 of the first to third axes of the test vehicle using a wheel / axle weight measurement system that has been subjected to span calibration, which is different from the wheel / axle weight measurement system to be inspected and calibrated. It memorize | stores in the arithmetic circuit 30 of an apparatus. The axle weights WS1, WS2, and WS3 are used for span calibration as reference values for the axle weights of the test vehicles.

  When the test vehicle is run in the same way as a general vehicle and the test vehicle arrives in front of the wheel / axle weight measurement system to be inspected, the general vehicle preceding the test vehicle has left the wheel / axle weight measurement system. Is confirmed, the operation unit 30a of the in-vehicle control device is operated, and a span inspection preparation command is transmitted. When receiving the span inspection preparation command, the load signal measuring device resets the cumulative addition memory and counter in the arithmetic circuit 14 used for span calibration, and transmits an inspection preparation OK signal to the in-vehicle control device. When the in-vehicle control device receives the inspection preparation OK signal, it displays the inspection preparation OK on the display 30b.

After confirming that the preceding vehicle does not exist on the first to third measuring instruments 4, 16, 18, as shown in FIG. 6, the operation unit 30 a of the in-vehicle control device is operated to load the zero adjustment command. It transmits to a signal measuring device (step S2). In the load signal measuring device, when the zero point adjustment command is received, the sampling of the first to third measuring instruments 4, 16, 18 in the state where no vehicle is present on the first to third measuring instruments 4, 16, 18. The weight measurement values Wa1, Wa2, and Wa3 are respectively taken into the R arithmetic circuit 14, the respective average values Wb1, Wb2, and Wb3 are calculated, and the stable zeros of the first to third measuring instruments 4, 16, and 18 are calculated. The weight value is obtained as an initial load value and stored in the memory of the arithmetic circuit 14 (step S4). Thereby, the sampling weight measurement values Wn1, Wn2, and Wn3 of the first to third measuring instruments 4, 16, and 18 are
Wn1 = k1. (Wb1-Wi1) -Wz1
Wn2 = k2 · (Wb2−Wi2) −Wz2
Wn3 = k3 · (Wb3-Wi3) -Wz3
At present, the sampling weight measurement values Wn1, Wn2, and Wn3 represent the zero point weight measurement values. The current zero point weight measurement values Wn1 to Wn3 are transmitted to the in-vehicle control device (step S6). At this time, the zero point weight measurement values Wn1 to Wn3 are accompanied by a measuring instrument number code indicating which of the first to third measuring instruments 4, 16, and 18 is the zero point weight measurement value. In the vehicle-mounted control device, the received zero weight measurement values Wn1 to Wn3 are displayed on the display 30b together with the measuring instrument number code for each measuring instrument (step S8).

  Zero adjustment is performed by the load signal measuring device (step S10). That is, the sampling weight measurement values Wn1, Wn2, Wn3 are added to the zero point storage registers Wz1, Wz2, Wz3. As a result, the sampling weight measurement values Wn1 to Wn3 become zero. The sampling weight measurement values Wn1, Wn2, Wn3, and the zero point values of the zero point storage registers Wz1, Wz2, Wz3 are transmitted to the vehicle-mounted control device with a code representing data and a measuring instrument number (step S12). In the vehicle-mounted control device, the received sampling weight measurement values Wn1, Wn2, Wn3 are displayed on the display 30b for each measuring instrument (step S14). All of the displayed values are zero, so that it is possible to confirm that the zero point adjustment of each measuring instrument has been completed on the test vehicle side.

The test vehicle is sequentially passed over the first to third measuring instruments 4, 16, and 18 at a low speed, for example, 5 to 10 km / h. As shown in FIG. 7, in the load signal measuring apparatus, the digital load signals Wa11 to Wa33 of the first to third measuring instruments 4, 16, and 18 with respect to the first to third axes are measured for each sampling period. Of course, this measurement is performed during a period when it is determined that the tire is on the first to third measuring instruments 4, 16, and 18 as described above. The sampling weight measurement values Wn11 to Wn13 of the first to third axes in the first weighing unit 4 are the sampling weight measurement values Wn21 to Wn23 of the first to third axes in the second weighing unit 16, respectively. The sampling weight values Wn31 to Wn33 of the first to third axes in the third measuring instrument 18 are calculated as follows (step S16).
Wn11 = k1 · (Wa11−Wi1) −Wz1
Wn12 = k1 · (Wa12−Wi1) −Wz1
Wn13 = k1 · (Wa13−Wi1) −Wz1
Wn21 = k2 · (Wa21−Wi2) −Wz2
Wn22 = k2 · (Wa22−Wi2) −Wz2
Wn23 = k2 · (Wa23−Wi2) −Wz2
Wn31 = k3 · (Wa31−Wi3) −Wz3
Wn32 = k3 · (Wa32−Wi3) −Wz3
Wn33 = k3 · (Wa33−Wi3) −Wz3

  In these sampling weight measurement values Wn11 to Wn33, for example, Wn11 is the sampling weight measurement value of the first axis in the first measuring instrument 4, and Wa11 is the sampling period of the first axis in the first measuring instrument 4. The digital load signal, Wn12 is the second axis sampling weight measurement value in the first weighing unit 4, Wa12 is the digital load signal for each second axis sampling period in the first weighing unit 4, and Wn13 is the first weighing value. The sampling weight value of the third axis in one measuring instrument 4, Wa 13 is a digital load signal for each sampling period of the third axis in the first measuring instrument 4. Wn11 to Wn13 are determined to be any of the first to third axes according to the generation order. The same applies to W21 to W33 and Wa21 to Wa33. These sampled weight measurement values Wn11 to Wn33 include a measuring instrument number code indicating which of the first to third measuring instruments 4, 16, and 18 is measured and an axle number code based on the generation order. It is attached.

  The span amounts Ws11 to Ws33 and the accumulated values Σs11 to Σs33 are calculated by using the Wa11 to Wa33 for each sampling period and the initial load values Wb1 to Wb3 corresponding to the respective measuring devices (step S18).

That is, in the first measuring instrument 4, the span amount Ws11 for the first axis, the span amount Ws12 for the second axis, and the span amount Ws13 for the third axis are
Ws11 = Wa11−Wb1
Ws12 = Wa12−Wb1
Ws13 = Wa13−Wb1
In the accumulated memories Σs11 to Σs13 provided in the arithmetic circuit 14,
Ws11 + Σs11 = Σs11
Ws12 + Σs12 = Σs12
Ws13 + Σs13 = Σs13
Perform the operation. Similarly, in the second and third measuring devices 16 and 18, the span amounts Ws21 to Ws33 and the accumulated values Σs21 to Σs33 of the span amount are calculated as follows.
Ws21 = Wa11−Wb2
Ws22 = Wa12−Wb2
Ws23 = Wa13−Wb2
Ws31 = Wa11−Wb3
Ws32 = Wa12−Wb3
Ws33 = Wa13−Wb3
Ws21 + Σs21 = Σs21
Ws22 + Σs22 = Σs22
Ws23 + Σs23 = Σs23
Ws31 + Σs31 = Σs31
Ws32 + Σs32 = Σs32
Ws33 + Σs33 = Σs33
The span amount is a value obtained by subtracting the initial load from the digital load signal, and the span coefficient is not multiplied.

  Next, the value of the counter C1 of the number of times of running of the test vehicle provided in the arithmetic circuit 14 of the load measuring device is increased by 1 (step S20). Note that the counter C1 and the cumulative memories Σs11 to Σs33 are reset when a span inspection preparation command is received.

  The sampling weight measurement values Wn11 to Wn33 are transmitted to the in-vehicle control device with the measuring instrument number code and the axle number code attached thereto (step S22).

  In the vehicle-mounted control device, Wn11 to Wn33 are converted into display value count levels for each of the first to third measuring instruments 4, 16, 18 and for each axle, and are displayed on the display 30b (step S24). At this time, if the reference values WS1 to WS3 described above are also displayed on the display 30b, the fluctuation state of the span at the present time can be visually confirmed.

In the in-vehicle control device, Wn11 to Wn33 are accumulated in the arithmetic circuit 30 and stored in the accumulated memories Σn11 to Σn33 provided in the arithmetic circuit 30 (step S26). That is, for the weight measurement values of the first to third shafts in the first measuring instrument 4,
Wn11 + Σn11 = Σn11
Wn12 + Σn12 = Σn12
Wn13 + Σn13 = Σn13
Perform the operation. Hereinafter, similarly, the weight measurement values of the first to third axes in the second and third measuring instruments 16 and 18 are Wn21 + Σn21 = Σn21
Wn22 + Σn22 = Σn22
Wn23 + Σn23 = Σn23
Wn31 + Σn31 = Σn31
Wn32 + Σn32 = Σn32
Wn33 + Σn33 = Σn33
Perform the operation.

  Also in the in-vehicle control device, the value of the counter C2 of the number of times of running the test vehicle is increased by 1 (step S28) and displayed on the display 30b (step S30). Using the values of Σn11 to Σn33, the average value of the measured values of the first to third axes in the first to third measuring instruments 4, 16, 18 is calculated, and the indicator 30b for each measuring instrument and each axle. (Step S31). In order to calculate the average value, the number of Wn11 samples to the number of Wn33 samples are counted.

  When all the wheels have passed through the first to third measuring instruments 4, 16, 18, a message to that effect is displayed on the display 30 b, and by confirming this display, the operation unit 30 a is operated. Then, a measurement completion signal is transmitted to the load signal measuring device (step S32). For detection of the completion of passage, for example, the third measuring instrument 18 is provided with an axle detection means, and when the number of axle detection signals of the detection means becomes 3 or more, the passage completion signal is output as a load signal measuring device. To the in-vehicle control device. The completion of the passage can be detected by other methods.

  As a result, one span check operation is completed, but if necessary, the test vehicle is again passed over the first to third measuring devices 4, 16, and 18, and the span check is performed again. Each time the span inspection is performed again, the count values of the test vehicle travel counters C1 and C2 increase by one, and the cumulative values of Σs11 to Σs33 and Σn11 to Σn33 also increase accordingly.

  Evaluate the displayed values of the weights of the first to third shafts in the first to third measuring instruments 4, 16, and 18 displayed on the display 30b and the number of times the test vehicle has traveled (C2). When it is determined that the span calibration is performed, it is confirmed that there is no vehicle on the first to third measuring instruments 4, 16, 18, and the operation unit 30 a of the in-vehicle control device is operated, and FIG. As shown, the span calibration command and the reference weight values WS1, WS2, WS3 of the first to third axes are transmitted to the load signal measuring device (step S34). The span calibration command can be performed only for the designated measuring instrument by designating the measuring instrument in accordance with the above judgment. The following describes the case where it is performed for all measuring instruments. Add a meter code to the command signal.

  When the load signal measuring device receives the span calibration command and the reference weight values WS1, WS2, and WS3, it converts the reference weight values WS1, WS2, and WS3 from the count level of the displayed weight value to the count level of the weight measurement value (4 Double) WS1 ′, WS2 ′, WS3 ′ (step S36).

Next, from the accumulated span amounts Σs11 to Σs13 of the first to third axes in the first measuring instrument 4 and the test vehicle travel times C1 and WS1 ′, span coefficients k11 and k12 on the first to third axes. , K13, and the span coefficient k1 of the measuring instrument 4 is calculated from these (step S38). That is, in the first measuring instrument 4, the reference weight WS1 ′ of the first shaft is WS1 ′ = k11 · (Σs11 / C1)
The span coefficient k11 is expressed as
k11 = Ws1 ′ / (Σs11 / C1)
Calculated by Similarly, in the first measuring instrument 4, the reference weight WS2 ′ of the second axis and the reference weight value WS3 ′ of the third axis are
WS2 ′ = k12 · (Σs12 / C1)
WS3 ′ = k13 · (Σs11 / C1)
Span coefficients k12 and k13 are expressed as follows:
k12 = WS2 ′ / (Σs12 / C1)
k13 = WS3 ′ / (Σs13 / C1)
Calculated by An average value (k11 + k12 + k13) / 3 of the span coefficients k11 to k13 is obtained and set as a new span coefficient k1 of the first measuring instrument 4.

Similarly, the span coefficient k21, k22, k23 in the first to third axes from the cumulative span amount of the first to third axes in the second measuring instrument 16, the number of test vehicle travels, and WS1 ′ to WS3 ′. And the span coefficient k2 of the second measuring instrument 16 is calculated from these (step S40). That is, k21 to k23 are
k21 = WS1 ′ / (Σs21 / C1)
k22 = Ws2 ′ / (Σs22 / C1)
k23 = WS3 ′ / (Σs23 / C1)
The average value (k21 + k22 + k23) / 3 of k21 to k23 is set as a new span coefficient k2 of the second measuring instrument 16.

Similarly, span coefficients k31, k32, and k33 for each axis are calculated from the weight measurement values of each axis in the third measuring instrument 18, and the span coefficient k3 for the third measuring instrument 18 is calculated from these (step). S42). That is, k31 to k33 are
k31 = WS1 ′ / (Σs31 / C1)
k32 = WS2 ′ / (Σs32 / C1)
k33 = WS3 ′ / (Σs33 / C1)
The average value (k31 + k32 + k33) / 3 of k31 to k33 is set as a new span coefficient k3 of the third measuring instrument 18.

Next, the digital load signals Wa1, Wa2, and Wa3 in a state where the vehicle is not on the first to third measuring instruments 4, 16, and 18 are respectively taken into the arithmetic circuit 14 by a predetermined number R, respectively, Average values Wb1, Wb2, and Wb3 are calculated and determined as stable initial load values of the first to third measuring instruments 4, 16, and 18 (step S44). And
Wn1 = k1. (Wa1-Wi1) -Wz1
Wn2 = k2 · (Wa2−Wi2) −Wz2
Wn3 = k3. (Wa3-Wi3) -Wz3
K1 to k3 are replaced with k1 to k3 determined as described above, the initial load values Wi1 to Wi3 are set to the initial load values Wb1 to Wb3 newly calculated as described above, Wz1 to Wz3 are reset, and span calibration is completed. (Step S46).

  When the above-mentioned test vehicle passes over the measuring instruments 4, 16, 18 during the normal operation after the span calibration is completed in this way, the weight measurement values Wn1, Wn2 of the respective axles according to the measuring instruments described above. , Wn3 is transmitted from the load signal measuring device to the vehicle-mounted control device, and the weight measurement value is displayed for each measuring instrument and each axis in the vehicle-mounted control device. Further, the load signal measuring device performs weight averaging of one axle weight measured by the weighing devices 4, 16, and 18 using a weighting coefficient corresponding to the vehicle speed, and the like, thereby obtaining a weight measurement value as a wheel / axle weight measurement system. System weight measurement value calculation means for calculating using the weight measurement value of each measuring instrument is provided. The axis-by-axis system weight measurement value output from the calculation means is transmitted to the in-vehicle control device. Usually, the user uses this system weight measurement as the axle weight. The in-vehicle control device also displays the system weight measurement value for each axle. By running the test vehicle with a known axle weight, the system weight measurement value and the display of the weight value for each weighing instrument that composes the system weight measurement are made to allow the user to recognize the span change as the system weight measurement value. The user recognizes the relationship with the breakdown of each measuring instrument and makes it useful for span readjustment and repair work.

  In the above embodiment, the first to third measuring instruments 4, 16, 18 are used. However, any one measuring instrument can be used, or the first to third measuring instruments 4, 16 can be used. , More than 18 scales can be used. Moreover, although it is a structure different from the 1st thru | or 3rd measuring instruments 4, 16, and 18, the measuring instrument which a vehicle passes on the measuring platform can also be used. In the above embodiment, the span inspection and calibration in the axle weight measurement have been described. However, the span inspection and calibration in the wheel weight measurement can be similarly performed. Moreover, in said embodiment, the weight 30n1 thru | or Wn33 of 1st thru | or 3rd axis | shaft and these Wn11 thru | or Wn33 separately to 1st thru | or 3rd measuring device 4,16,18 in the indicator 30b of a vehicle-mounted control apparatus. Although the average value calculated based on the cumulative value Σn11 to Σn33 based on the count value C2 of the number of times the test vehicle has traveled is displayed for each measuring instrument and each axle, only one of them can be displayed.

4 16 18 Measuring device 13 Wireless transmission / reception circuit (wireless communication means)
14 Arithmetic circuit (Load signal measuring device)
30 Arithmetic circuit (on-vehicle controller)
30b Display (display means)
32 Wireless transmission / reception circuit (wireless communication means)

Claims (4)

At least one weighing instrument with a weighing platform on the road surface;
A load signal measuring device for measuring the weight of a wheel or axle of a test vehicle that passes at least once on the weighing platform;
An in-vehicle control device provided in the test vehicle,
Prepared,
The test vehicle has a known weight of the wheel or axle;
Wireless communication means for wirelessly transmitting the weight of the wheel or axle of the test vehicle measured by the measuring instrument from the load signal measuring device to the on-vehicle control device is provided to the load signal measuring device and the on-vehicle control device. Provided,
The vehicle-mounted control device is a wheel / axle weight measurement system comprising display means for displaying one or both of the weight of the wheel or axle of the test vehicle transmitted wirelessly and an average value thereof.   2. The wheel / axle weight measuring system according to claim 1, wherein a plurality of the measuring devices are provided, and the display means displays one or both of a weight of the wheel or the axle and an average value thereof, or the plurality of measuring devices. Wheel / axle weight measurement system to be displayed separately.   3. The wheel / axle weight measuring system according to claim 1 or 2, wherein the display means also displays the number of weight measurements by the vehicle in the measuring instrument. The wheel / axle measuring system according to claim 1 or 2,
The vehicle-mounted control device stores the weight of the wheel or axle corresponding to the current load capacity of the test vehicle as a reference value for span calibration,
When the test vehicle passes over the weighing platform, the load signal measuring device measures the weight value of the wheel or axle of the test vehicle,
The span of the measuring instrument is calibrated based on the measured weight value of the wheel or axle of the test vehicle and the reference value for span calibration stored in the in-vehicle control device by a command signal from the in-vehicle control device. A wheel / axle weight measuring system provided in the load signal measuring device with a span calibration means.

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