Dump truck

Abstract

This dump truck is provided with: a vehicle body and wheels; a cargo bed which is supported on the vehicle body so as to be capable of rising and falling and onto which cargo is loaded; a suspension cylinder provided between the vehicle body and the wheels; a pressure sensor that measures a pressure of the suspension cylinder; an inclination angle sensor that measures an inclination of the vehicle body; an acceleration sensor that measures an acceleration acting on the vehicle body; a steering angle sensor that detects a steering angle of the vehicle body; and a controller that calculates a payload of the cargo bed. The controller calculates the payload on the basis of a measurement value of the pressure sensor, a measurement value of the inclination angle sensor, a measurement value of the acceleration sensor, and a measurement value of the steering angle sensor.

Description

Dump truck

[0001] The present invention relates to a dump truck equipped with logic that improves payload measurement accuracy.

[0002] Accurately measuring the payload (load weight) of construction machinery is important for customers who own the machinery to understand production volume, and is also important from a safety perspective for maintaining the life of the machinery. Patent Document 1 discloses a system that measures and displays the payload at appropriate times to prevent the payload from exceeding a specified value. Patent Document 2 also discloses a method for measuring the payload by detecting the cylinder pressure of a suspension cylinder.

[0003] Patent No. 6027248 Specification Patent No. 5160468 Specification

[0004] Dump truck drivers need to grasp the payload as soon as possible after loading is complete to determine whether the payload meets the conditions for being within a specified range. However, measurement accuracy is low when the vehicle is stationary due to the vehicle's inclination and road conditions. Furthermore, it is difficult to predict road conditions and the driver's driving style once the vehicle has started traveling. Patent Document 2 discloses a method of temporarily halting measurement when a decrease in measurement accuracy is expected due to such constantly changing conditions. However, this method has the disadvantage of lengthening the payload measurement time and reducing production efficiency. Furthermore, because payload measurement accuracy decreases due to changes in vehicle posture, a function has been proposed to invalidate the calculated payload value when traveling on a curved route. However, this method has the problem of reducing measurement accuracy when it is necessary to measure the payload while traveling on a curved road.

[0005] When the vehicle is moving, it is subjected to both longitudinal and lateral acceleration. The longitudinal acceleration is particularly large when the vehicle starts moving and the payload is measured. Furthermore, when the vehicle turns after starting to move, it is also subjected to lateral acceleration. There is a need for technology that can accurately correct the effects of these accelerations on the payload.

[0006] An object of the present invention is to provide a dump truck incorporating logic that can accurately measure the payload immediately after the start of traveling.

[0007] In order to solve the above problem, the dump truck of the present invention is a dump truck comprising a vehicle body and wheels, a loading platform supported on the vehicle body so that it can be raised and lowered and on which cargo is loaded, a suspension cylinder provided between the vehicle body and the wheels, a pressure sensor that measures the pressure in the suspension cylinder, an inclination angle sensor that measures the inclination of the vehicle body, an acceleration sensor that measures the acceleration acting on the vehicle body, a steering angle sensor that detects the steering angle of the vehicle body, and a controller that calculates the payload of the loading platform, wherein the controller calculates the payload based on the measurement values ​​of the pressure sensor, the measurement values ​​of the inclination angle sensor, the measurement values ​​of the acceleration sensor, and the measurement values ​​of the steering angle sensor.

[0008] According to the dump truck of the present invention, it is possible to further improve the payload measurement accuracy without changing the measurement time required for determining the payload, thereby preventing overloading and underloading, preventing a decrease in work efficiency, and extending the life of the vehicle body.

[0009] Further features related to the present invention will become apparent from the description of the present specification and the accompanying drawings. In addition, the problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0010] 7 is a side view of a dump truck according to an embodiment of the present invention; FIG. 8 is a perspective view of the dump truck according to an embodiment, viewed diagonally from the upper left; FIG. 9 is a block diagram showing the functions of a controller mounted on a conventional dump truck; FIG. 10 is a block diagram showing the functions of a controller mounted on a dump truck according to an embodiment; FIG. 11 is a block configuration diagram of payload measurement logic mounted on the controller; FIG. 12 is a diagram showing payload behavior after the start of traveling and the amount of deviation between the traveling payload and the loaded payload; FIG. 13 is a diagram showing payload behavior and the amount of deviation between the traveling payload and the loaded payload when corrections for longitudinal acceleration and steering angle are applied to the graph of FIG. 6; FIG. 14 is a diagram schematically showing the influence of acceleration and steering angle on the payload; FIG. 15 is a diagram showing the relationship between acceleration correction time and the degree of deviation between the traveling payload and the loaded payload; FIG. 16 is a flowchart showing processing executed by a controller; FIG. 17 is a diagram showing a display unit inside the cab; FIG. 18 is a diagram showing a display unit outside the cab.

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. The following describes the configuration of a mining dump truck (hereinafter abbreviated as "dump"; equivalent to a large vehicle) and the function of the payload measurement logic.

[0012] A dump truck (dump truck) 1 is a mining machine as shown in Figure 1. As shown in Figure 1, the dump truck 1 is supported by a pair of left and right front wheels 5 and two pairs of left and right rear wheels 4, axles 7 connecting the left and right front wheels and the rear wheels, respectively, and a sturdy frame body 12. A body (cargo bed) 2 for loading earth and sand is mounted on the body 12 so that it can be raised and lowered. A hoist cylinder 8 connects the body 2 to the body 12. The dump truck 1 also has a fuel tank 10 and a cab 3 for an operator to drive. The dump truck 1 is equipped with an engine 6 that serves as a power source.

[0013] A conventional method for calculating the payload of a dump truck 1 is to perform calculations based on suspension cylinder pressure. Suspension cylinders 30 are provided between the vehicle body 12 and the wheels (front wheels 5 and rear wheels 4). The suspension cylinders 30 include a front suspension cylinder 11 and a rear suspension cylinder 13. As shown in FIG. 2 , the front suspension cylinders 11, which include a right-side front suspension cylinder 14 and a left-side front suspension cylinder 15, are provided in front of the vehicle body 12, and the rear suspension cylinders 13, which include a right-side rear suspension cylinder 16 and a left-side rear suspension cylinder 17, are provided in the rear of the vehicle body 12.

[0014] As shown in FIGS. 1 and 2 , the dump truck 1 is equipped with a pressure sensor 40 that measures the pressure in the suspension cylinder 30. The pressure sensor 40 includes a front pressure sensor 41 that measures the pressure in the front suspension cylinder 11 and a rear pressure sensor 42 that measures the pressure in the rear suspension cylinder 13. An inclination angle sensor 19 that measures the inclination of the vehicle body 12 is installed inside the cab 3 of the dump truck 1. The dump truck 1 is equipped with a longitudinal acceleration sensor (acceleration sensor) 21 that measures the acceleration acting in the longitudinal direction of the vehicle body 12, and a steering angle sensor 20 that detects the steering angle of the vehicle body 12. The longitudinal acceleration sensor 21 also functions as a speed sensor by integrating the measured value. The dump truck 1 is also equipped with a CCU (controller) 18 that calculates the payload of the body 2.

[0015] The payload is calculated in a CCU (Central Control Unit) 18 based on the pressure in the suspension cylinder 30 detected by a pressure sensor 40, the inclination angle of the vehicle body 12 detected by a tilt angle sensor 19, the steering angle of the vehicle body 12 detected by a steering angle sensor 20, and the acceleration acting on the vehicle body 12 detected by a longitudinal acceleration sensor 21.

[0016] Here, the background to the invention will be explained. In order to solve the above-mentioned problems, the inventors have conducted extensive research, focusing on the conditions under which payload measurement accuracy deteriorates. First, payload can be broadly divided into two categories: running payload, which is measured when the vehicle body is running stably, and loaded payload, which is measured when the vehicle starts running immediately after loading. Since the object of the invention is to improve the payload measurement accuracy immediately after the vehicle starts running after loading, the focus is on loaded payload. By improving the measurement accuracy of loaded payload, it becomes possible to grasp the payload as accurately as possible as early as possible.

[0017] Measurement accuracy deteriorates due to the influence of vehicle behavior after the vehicle starts moving. Vehicle behavior includes turning and acceleration when starting. Therefore, by analyzing the influence of these vehicle behaviors, we have invented a logic for measuring with high accuracy.

[0018] The payload calculation logic installed in a conventional dump truck 1 will be described with reference to FIG. 3 . As shown in FIG. 3 , in the conventional dump truck 1, the measured values ​​of the front pressure sensor 41, the rear pressure sensor 42, and the tilt angle sensor 19 are input to the payload calculation unit 22 in the controller 18. The payload calculation unit 22 adds load correction, tilt correction, and other calculations (such as subtracting the weight of the loading platform) to these input values ​​to calculate the real-time payload. The real-time payload refers to the payload value calculated at that time. The load correction is a correction made to correct a weight imbalance caused by the balance of the load on the loading platform, and the tilt correction is a correction made to correct a weight imbalance caused by the tilt angle of the vehicle body 12.

[0019] After the start of measurement, the real-time payload when the vehicle body 12 begins to travel stably is treated as the operating payload, and when the traveling speed of 1 km / h or more continues for 6.4 seconds after the start of measurement, the average real-time payload during that period is treated as the loaded payload.

[0020] The inventor then discovered that there is a discrepancy between the operating payload, which is the value when the vehicle is in a stable state, and the loaded payload, which is the value immediately after the vehicle starts to travel, and that the cause of this is the inertial and centrifugal forces acting on the vehicle body 12 immediately after the vehicle starts to travel.

[0021] That is, when the vehicle body 12 starts moving and accelerates forward, a pitching moment is generated around the center of gravity of the vehicle body 12, and a force acts on the vehicle body 12 in a direction that lifts the front of the vehicle body 12. This causes the front suspension supporting the front of the vehicle body 12 to extend, and the cylinder pressure drops. This pressure drop settles down after a few seconds, but while the cylinder pressure is dropping, the real-time payload drops, and as a result, the loaded payload drops, and a low value that deviates from the operating payload is calculated.

[0022] A similar phenomenon occurs when steering is performed; steering while traveling at a constant speed reduces the real-time payload and the loaded payload as well.

[0023] As described above, it has been discovered that in order to accurately calculate the loaded payload, it is necessary to consider the effects of the inertial force and centrifugal force acting on the vehicle body 12. Therefore, in this embodiment, as shown in Figure 4, in addition to the pressure measurement value of the suspension cylinder 30 from the pressure sensor 40 and the tilt angle measurement value from the tilt angle sensor 19, which are input values ​​to the conventional payload measurement logic, a longitudinal acceleration measurement value from the longitudinal acceleration sensor 21 and a steering angle measurement value from the steering angle sensor 20 are input, and correction terms corresponding to these measurement values ​​are added to the suspension pressures (PF: front suspension pressure, PR: rear suspension pressure).

[0024] Furthermore, through further analysis by the inventors, it was found that while the correction based on the measurement value of the longitudinal acceleration sensor 21 needs to be applied to both the front and rear suspension pressures, a sufficient correction effect can be obtained by applying the correction based on the measurement value of the steering angle sensor 20 only to the front suspension pressure.

[0025] FIG. 5 shows a specific configuration of the payload calculation logic executed by the controller 18 (payload calculation unit 22) in this embodiment. In this payload measurement logic, the controller 18 first receives the pressures applied to the four suspensions in S9 and the inclination angle of the vehicle body 12 obtained from the inclination angle sensor 19 in S10. The controller 18 then calculates a resultant force FF' obtained by multiplying the pressure in each front suspension cylinder 11 by the pressure-receiving area of ​​the front suspension cylinder 11, and a resultant force FR' obtained by multiplying the pressure in each rear suspension cylinder 13 by the pressure-receiving area of ​​the rear suspension cylinder 13. Next, in S12, the controller 18 adds a correction corresponding to the longitudinal acceleration input from the longitudinal acceleration sensor 21 to each of the resultant forces FF' and FR'. Next, in S13, the controller 18 adds a correction corresponding to the steering angle input from the steering angle sensor 20 to the resultant force FF'. The correction corresponding to the acceleration and steering angle, which is one of the features of the present invention, will be described in detail below. The reason why it is not added to the resultant force FR' is that the model analysis performed by the inventors has revealed that the steering angle does not affect the resultant force FR', as described above.

[0026] Next, the controller 18 calculates the sprung load Ft as a result of the resultant forces FF and FR in S15, using the resultant forces FF and FR obtained by the corrections made in S12 and S13. The controller 18 also calculates the front / rear suspension load ratio FF / FR in S16 as the ratio of the resultant forces FF and FR. Meanwhile, the payload calculation unit 22 of the controller 18 calculates the vehicle body tilt angle in the longitudinal direction of the dump truck 1 by performing signal processing on the inclination angle sensor 19 in S14 to extract only the inclination component through a moving average filter, in order to detect high-frequency acceleration components due to vibrations during traveling in addition to the inclination component of the road surface. The controller 18 also stores a table relating to correction values ​​of the sprung load Ft and the suspension load ratio FF / FR for the front / rear vehicle body tilt angle. The payload calculation unit 22 then uses the tables to calculate the sprung load Ft and the suspension load ratio FF / FR in S17 and S18, respectively, and corrects them based on the signal-processed vehicle body tilt angle so that they become the sprung load Ft and the suspension load ratio FF / FR when the vehicle body is not tilted.The payload calculation unit 22 then determines whether the vehicle is moving or stopped based on the signal from the speed sensor (longitudinal acceleration sensor 21) in S19 and S20, and multiplies the sprung load Ft and the suspension load ratio FF / FR by a coefficient corresponding to the determination result, respectively, to correct the sprung load Ft and the suspension load ratio FF / FR. The payload calculation unit 22 then determines the eccentric position of the load from the suspension load ratio FF / FR corrected in S21 according to the vehicle body tilt angle and running state, and applies a predetermined calculation formula to the suspension load ratio FF / FR to calculate a suspension load ratio FF / FR (Ft correction ratio) for correcting the sprung load Ft corrected in accordance with the vehicle body tilt angle to a standard position.The payload calculation unit 22 then calculates the load on the suspension in S22 by multiplying the suspension load ratio, which is the ratio of the designed front and rear loads applied to the suspension, by the load-corrected sprung load Ft, which is obtained by dividing the sprung load Ft corrected in S19 by the eccentricity-corrected suspension load ratio FF / FR calculated in S21.Then, in S23, the payload calculation unit 22 calculates the total vehicle weight taking into account the load under the suspension. In S24, the payload calculation unit 22 subtracts the unladen mass from this to calculate the real-time payload obtained in real time.

[0027] Next, we will discuss how the loaded payload changes when longitudinal acceleration correction and steering angle correction are added to the payload. The graph in Figure 6 shows the behavior of the payload at the start of travel and the deviation between the travel payload and the loaded payload. As mentioned above, the payload, which fluctuates in real time, tends to temporarily decrease due to the influence of inertial forces that occur immediately after travel begins. Due to this influence, the average real-time payload during the loaded payload calculation time tends to decrease, and the loaded payload also tends to decrease. As a result, the deviation from the travel payload measured during stable travel increases. For these reasons, the measurement accuracy of the loaded payload is lower than that of the travel payload.

[0028] Next, the graph in Figure 7 shows a graph in which the payload measured as being smaller than it actually is due to the influence of longitudinal acceleration and steering angle is corrected by adding longitudinal acceleration correction and steering angle correction at each time in real time to the graph in Figure 6. By performing the correction during the loaded payload calculation time, the loaded payload, which is the average value during the calculation time, becomes equal to the operating payload, so the difference between the operating payload and the loaded payload is small and measurement accuracy is improved.

[0029] Based on the above principle, highly accurate measurements are possible without changing the calculation time for the loaded payload.

[0030] Here, one possible method for improving measurement accuracy is to change the loaded payload calculation time. Extending the calculation time includes a period of time when the vehicle is traveling more stably, thereby improving measurement accuracy. However, this method has the disadvantage of slowing down the time required to determine the payload, which reduces production efficiency. Next, shortening the calculation time allows the payload to be determined in a shorter time, which improves production efficiency. However, this method has the disadvantage of increasing the amount of variance due to the short time, making the payload value unstable depending on the situation. Therefore, this embodiment can be said to be a method that improves both production efficiency and measurement accuracy compared to other methods.

[0031] Next, specific examples of methods for correcting payload according to acceleration and / or steering angle will be described with reference to Figures 8 and 9. Figure 8 is a graph that uses model analysis to show the extent to which acceleration and steering angle affect payload. Figure 9 is a graph that shows the deviation between traveling payload and loaded payload versus the time over which acceleration is corrected. In Figure 8, the vertical axis represents the payload value in real time, the acceleration represents the value when a constant acceleration is maintained immediately after starting, and the steering angle represents the value when traveling at a constant speed while maintaining the steering angle.

[0032] As shown in Figure 8, in the dump truck 1 used in this embodiment, the payload value decreases as the acceleration increases, and it can be seen that it decreases by about 10% at full acceleration. On the other hand, in the case of steering, although the effect is not as great as that of acceleration, it can be seen that the payload value decreases by about 1% at full steering. For example, as shown in Figure 8, when the steering angle is ±26.8°, a difference of about 2.0 t occurs in the calculated payload value compared to the payload value when the steering angle in a straight-ahead state is 0°.

[0033] From this, the inventors have found that it is preferable to correct the steering angle payload for 6.4 seconds from immediately after start until the operational payload is determined, and to correct the acceleration payload for several seconds (<6.4 seconds) immediately after start.

[0034] More specifically, in the case of acceleration, for example, an additive correction is made according to the acceleration value to set the real-time payload value to the value when acceleration is 0. That is, in the case of full acceleration (acceleration = 0.5 m / s^2) immediately after starting, a correction is made by adding 19.3 t to the real-time payload. In other words, a correction is made by adding the difference between the measured real-time payload and the payload when acceleration is 0 to the measurement value of the pressure sensor 40, which indicates the real-time payload. The same is true for the steering angle, where a subtractive correction is made to the measured steering angle as shown in FIG. 8. These corrections may be made simultaneously, or only one of them may be made.

[0035] A graph showing the correction time for acceleration is shown in Figure 9. As shown in Figure 9, the inventors have found that correcting the payload according to the acceleration for 1.6 seconds immediately after starting minimizes the deviation between the running payload and the loaded payload.

[0036] A specific flowchart executed by the payload calculation unit 22 in this embodiment is shown in Figure 10. First, in step S1, it is determined whether the vehicle body 12 is moving. Next, if in step S1 the vehicle body 12 is not moving but is stationary, the process proceeds to step S2, where the flowchart ends without calculating the loaded payload. On the other hand, if it is determined in step S1 that the vehicle body 12 is moving, it is determined in step S3 whether the "conditions for calculating the loaded payload" are met. If the conditions are not met, the process returns to step S1, and the determination in step S1 is repeated until the loaded payload calculation conditions are met. Here, the "conditions for calculating the loaded payload" refer to four conditions: the loaded weight when loaded has not been determined; the body 2 is in a seated state; the vehicle is continuously moving forward at a traveling speed greater than or equal to a specified value; and the payload calculated in real time is equal to or greater than a specified percentage of the nominal loaded weight.

[0037] If it is determined in step S3 that the loaded payload calculation conditions are met, in step S4, a correction according to the longitudinal acceleration is added to the pressure (suspension pressure) of each suspension cylinder 30. Next, in step S5, a correction according to the steering angle is added to the pressure of the front suspension cylinder 11. Note that steps S4 and S5 may be performed in the reverse order, or may be performed simultaneously.

[0038] Next, in step S6, a load correction and a tilt correction are added to the pressure of the suspension cylinder 30, and a real-time payload measured in real time by the calculation system is calculated. Next, in step S7, if the elapsed time from the start of the loaded payload calculation is less than a predetermined measurement time (= t seconds), the process returns to step S4 again, where corrections according to the longitudinal acceleration and steering angle are added to the pressure of each suspension cylinder 30. When the calculation elapsed time becomes t seconds or more, the process proceeds to step S8. In step S8, the average value of the real-time payload during the calculation time t seconds becomes the loaded payload, and since the loaded payload is determined from this point, this flowchart ends. Note that the predetermined measurement time t seconds is, for example, 6.4 seconds as described in FIG. 3.

[0039] Fig. 11 is a diagram showing information displayed on the display unit 23 inside the cab 3. As shown in Fig. 11, the display unit 23 inside the cab displays various information that are conditions for selecting a work mode, such as the vehicle speed and load information, but the currently measured real-time payload value is displayed on the display unit 23 in the center of the tachometer that shows the RPM of the engine 6. By providing the display unit 23 inside the cab 3 in this way that displays the real-time payload, the operator can easily check the current real-time payload.

[0040] FIG. 12 is a side view showing the side of the dump truck 1 according to a modified example. In this modified example, a display unit 24 is provided on the deck 9. The display unit 24 displays the currently measured real-time payload value, similar to the display unit 23 in the cab 3. This display unit 24 is intended to notify third parties of the real-time payload value. When the value exceeds 120% of the maximum load capacity of the dump truck 1, indicating an overload state, the display unit 24 flashes as shown in FIG. 12, thereby informing third parties of the overload state. The display method for indicating an overload state is not limited to flashing, and may also be a change in color to another conspicuous color (such as a fluorescent color). The real-time payload value may also be transmitted to the outside by a communication device mounted on the dump truck 1.

[0041] In the case of overloading, not only can the display method on the display unit 24 be changed to notify a third party, but the CCU 18 of the dump truck 1 can also impose a speed limit on the dump truck 1. By imposing a speed limit on the dump truck 1 when the dump truck is overloaded, even if the operator steps on the accelerator without noticing the overloading, the dump truck will not accelerate, so the operator will be aware of the overloading and can quickly return to the loading site, unload the cargo, and resolve the overloading.

[0042] The above-described embodiments of the present invention provide the following advantageous effects: (1) A dump truck according to the present invention includes a vehicle body and wheels, a loading platform supported on the vehicle body so as to be able to rise and fall and on which cargo is loaded, a suspension cylinder provided between the vehicle body and the wheels, a pressure sensor that measures the pressure in the suspension cylinder, a tilt angle sensor that measures the tilt of the vehicle body, an acceleration sensor that measures the acceleration acting on the vehicle body, a steering angle sensor that detects the steering angle of the vehicle body, and a controller that calculates the payload of the loading platform, and the controller calculates the payload based on the measurement values ​​of the pressure sensor, the tilt angle sensor, the acceleration sensor, and the steering angle sensor.

[0043] The above configuration further improves payload measurement accuracy without changing the measurement time required to determine the payload, thereby preventing overloading and underloading, preventing a decrease in work efficiency, and extending the life of the vehicle body.

[0044] (2) The controller corrects the pressure sensor measurement value in accordance with the acceleration sensor measurement value and the steering angle sensor measurement value. More specifically, (1) is calculated in this manner.

[0045] (3) The suspension cylinders include front and rear suspension cylinders, the pressure sensors include a front pressure sensor that measures the pressure of the front suspension cylinder and a rear pressure sensor that measures the pressure of the rear suspension cylinder, and the controller corrects the measurement values ​​of the front and rear pressure sensors according to the measurement values ​​of the acceleration sensor, and corrects the measurement value of the front pressure sensor according to the measurement value of the steering angle sensor. Through diligent research, the inventors have found that it is necessary to correct only the measurement value of the front suspension cylinder pressure sensor for the measurement value of the steering angle sensor.

[0046] (4) The controller calculates the payload by adding a correction based on the state of the cargo loaded on the loading platform to the pressure sensor measurement value. This enables appropriate weight balance correction based on the position of the cargo, etc.

[0047] (5) The controller calculates the payload by adding a correction based on the tilt angle of the vehicle body to the pressure sensor measurement value. This makes it possible to calculate the payload appropriately even when the vehicle body is traveling on a slope.

[0048] (6) If the calculated payload exceeds the vehicle's load capacity, the controller limits the vehicle's travel speed. This prevents the vehicle from accelerating even if the operator depresses the accelerator without noticing the overload, enabling the operator to quickly return to the loading site, unload the cargo, and resolve the overload.

[0049] (7) The controller corrects the pressure sensor measurement value by adding the difference between the measured real-time payload and the real-time payload when the acceleration and / or steering angle is 0, depending on the acceleration sensor measurement value and the steering angle sensor measurement value. Specifically, the correction performed in the present invention is performed in this manner.

[0050] It should be noted that the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to embodiments that include all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete part of the configuration of each embodiment, or to add or replace other configurations.

[0051] 1 Dump (dump truck), 2 Body (cargo bed), 11 Front suspension cylinder, 12 Vehicle body, 13 Rear suspension cylinder, 14 Right side front suspension cylinder, 15 Left side front suspension cylinder, 16 Right side rear suspension cylinder, 17 Left side rear suspension cylinder, 18 CCU (controller), 19 Tilt angle sensor, 20 Steering angle sensor, 21 Forward / rear acceleration sensor (acceleration sensor), 30 Suspension cylinder, 40 Pressure sensor, 41 Front pressure sensor, 42 Rear pressure sensor

Claims

1. A dump truck comprising: a vehicle body and wheels; a loading platform supported on the vehicle body so that it can be raised and lowered and on which cargo is loaded; a suspension cylinder provided between the vehicle body and the wheels; a pressure sensor that measures the pressure of the suspension cylinder; an inclination angle sensor that measures the inclination of the vehicle body; an acceleration sensor that measures the acceleration acting on the vehicle body; a steering angle sensor that detects the steering angle of the vehicle body; and a controller that calculates the payload of the loading platform, wherein the controller calculates the payload based on the measurement values ​​of the pressure sensor, the measurement values ​​of the inclination angle sensor, the measurement values ​​of the acceleration sensor, and the measurement values ​​of the steering angle sensor.

2. A dump truck according to claim 1, wherein the controller corrects the measurement value of the pressure sensor in accordance with the measurement value of the acceleration sensor and the measurement value of the steering angle sensor.

3. A dump truck according to claim 2, wherein the suspension cylinders include a front suspension cylinder and a rear suspension cylinder, the pressure sensors include a front pressure sensor that measures the pressure of the front suspension cylinder and a rear pressure sensor that measures the pressure of the rear suspension cylinder, and the controller corrects the measurement values ​​of the front pressure sensor and the rear pressure sensor according to the measurement value of the acceleration sensor, and corrects the measurement value of the front pressure sensor according to the measurement value of the steering angle sensor.

4. A dump truck according to claim 1, wherein the controller calculates the payload by adding a correction corresponding to the state of the cargo loaded on the bed to the measurement value of the pressure sensor.

5. A dump truck according to claim 1, wherein the controller calculates the payload by adding a correction corresponding to the tilt angle of the vehicle body to the measurement value of the pressure sensor.

6. A dump truck according to claim 1, wherein the controller limits the traveling speed of the vehicle body when the calculated payload exceeds the load capacity of the vehicle body.

7. A dump truck according to claim 2, wherein the controller corrects the measurement value of the pressure sensor by adding the difference between the measured real-time payload and the real-time payload when the acceleration and / or steering angle is 0, depending on the measurement value of the acceleration sensor and the measurement value of the steering angle sensor.

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