A method and system for measuring the load of a truck

Abstract

A truck load measurement method and system for measuring the load of a truck, the truck comprising a carriage having an opposite driving end and a pivotal end, an oil-gas suspension system having a plurality of suspension oil cylinders, and a hydraulic lifting system having a lifting oil cylinder; the truck load measurement method comprising: when the carriage is loaded with goods, calculating the actual distance between the center of mass of the goods and the pivotal end according to the pressure generated by the plurality of suspension oil cylinders, the distance between the plurality of suspension oil cylinders, and a preset distance between the center of mass of the goods and the pivotal end; controlling the lifting oil cylinder to provide a lifting force to the carriage, and balancing the lifting force with the pressure generated by the goods; determining a static lifting pressure in the process of balancing the lifting force with the pressure generated by the goods; and calculating the actual mass of the goods as the load according to the static lifting pressure, the actual distance between the center of mass of the goods and the pivotal end, and the distance between the driving end and the pivotal end.

Description

Technical Field

[0001] This invention relates to the field of engineering vehicles, and in particular to a method and system for measuring the load capacity of freight vehicles. Background Technology

[0002] When measuring the load capacity of large trucks, such as mining dump trucks, the overall load capacity can be converted using the hydropneumatic suspension system that supports the truck bed. This involves determining the load capacity based on the pressure changes within the hydropneumatic suspension system. A typical method for measuring truck load capacity based on this principle includes the following steps: measuring the pressure in each suspension cylinder of the hydropneumatic suspension system; calculating the pressure borne by each suspension cylinder based on its pressure and cross-sectional area; calculating the total pressure borne by all suspension cylinders based on the pressure borne by each cylinder; converting the total pressure borne by all suspension cylinders into the truck's total load mass; calculating the total load mass of the truck both empty and loaded, and then using the difference between the loaded and empty load masses as the weight of the cargo, i.e., the load capacity.

[0003] For example, Figure 1 The diagram illustrates a schematic representation of an exemplary method for measuring the load capacity of a truck, such as a mining dump truck, in the prior art. Figure 1 The mining dump truck shown has a hydropneumatic suspension system for supporting the truck bed. This system includes six suspension cylinders distributed at different locations on the truck. Let the pressures in these six cylinders be defined as P1 to P6, and the cross-sectional areas as S1 to S6. Based on the aforementioned load conversion principle, the total pressure F on these six cylinders is F = P1S1 + P2S2 + P3S3 + P4S4 + P5S5 + P6S6. The total load mass M can then be calculated from this total pressure F using the following formula:

[0004]

[0005] Where g is the acceleration due to gravity. Following the above steps, calculate the total load mass of the mining dump truck when it is empty and when it is loaded. Then calculate the difference between the total load mass of the mining dump truck when loaded and the total load mass when it is empty. This difference can be used as the mass of the goods loaded on the mining dump truck, i.e., the load capacity.

[0006] However, the existing methods for measuring the load capacity of trucks mentioned above usually have the following drawbacks: the method treats the loading process of the entire vehicle as a static force balance process, the data source is singular, there is a lack of a secondary verification mechanism, and it does not take into account the errors that may occur in the actual use of the hydropneumatic suspension system. When the hydropneumatic suspension system malfunctions, it cannot accurately reflect the vehicle load information.

[0007] In view of this, it is necessary to provide a more novel method and system for measuring the load capacity of freight cars to solve the above-mentioned problems of the prior art. Summary of the Invention

[0008] Based on the aforementioned problems in the prior art, the purpose of this invention is to provide a method and system for measuring the load capacity of trucks, which can measure the load capacity of trucks more accurately than the prior art, and can also provide timely feedback and compensation for the load capacity measurement results when errors occur in the load capacity measurement process of the hydropneumatic suspension system.

[0009] An embodiment of the present invention provides a method for measuring the load capacity of a freight truck, the freight truck including a cargo box, a hydropneumatic suspension system for supporting the cargo box, and a hydraulic lifting system for driving the cargo box to lift. The hydropneumatic suspension system includes a plurality of suspension cylinders, and the hydraulic lifting system includes a lifting cylinder. The cargo box has a drive end and a pivot end that are oppositely arranged and capable of being raised and lowered under the drive of the lifting cylinder. The method for measuring the load capacity of the freight truck includes the following steps: when the cargo box is loaded with goods, the method measures the load capacity based on the pressure generated by the plurality of suspension cylinders, the load capacity of the cargo box, and the load capacity of the freight truck. The distance between the multiple suspension cylinders and the preset distance between the center of gravity of the cargo and the pivot end are used to calculate the actual distance between the center of gravity of the cargo and the pivot end of the carriage; the lifting cylinders are controlled to provide lifting force to the carriage, and the lifting force is balanced with the pressure generated by the cargo; the static lifting pressure is determined during the process of balancing the lifting force and the pressure generated by the cargo; the actual mass of the cargo is calculated as the load capacity based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end, and the distance between the drive end and the pivot end.

[0010] In some embodiments, the truck has six wheels, including two front wheels, two middle wheels, and two rear wheels; the number of suspension cylinders is also six, with one suspension cylinder located above each wheel; characterized in that the formula for calculating the actual distance between the center of gravity of the cargo and the pivot end of the truck bed is:

[0011]

[0012] D = x + Δ;

[0013] Wherein, P1S1, P2S2, P3S3, P4S4, P5S5, and P6S6 are the pressures generated by the six suspension cylinders, respectively; L2 is the distance between the suspension cylinder located above the rear wheel and the suspension cylinder located above the middle wheel on the same side of the truck; L3 is the distance between the suspension cylinder located above the middle wheel and the suspension cylinder located above the front wheel on the same side of the truck; x is the preset distance between the center of gravity of the cargo and the pivot end of the truck bed; Δ is the offset distance of the center of gravity of the cargo along the length of the truck; and D is the actual distance between the center of gravity of the cargo and the pivot end of the truck bed.

[0014] In some implementations, the formula for calculating the actual mass of the goods is:

[0015]

[0016] Where M is the actual mass of the cargo, P7S7 is the static lifting pressure, L1 is the distance between the drive end and the pivot end of the carriage, and g is the gravitational acceleration.

[0017] In some embodiments, controlling the lifting cylinder to provide lifting force to the carriage and balancing the lifting force with the pressure generated by the cargo includes: controlling the lifting cylinder to generate a gradually increasing lifting force from 0 to the drive end according to a preset lifting force change rate, so that the carriage gradually overcomes the weight of the cargo and forms a lifting trend under the drive of the gradually increasing lifting force; when the drive end of the carriage is just about to be lifted, it is considered that the lifting force and the pressure generated by the cargo have reached a balance.

[0018] In some embodiments, determining the static lifting pressure during the process of balancing the lifting force with the pressure generated by the cargo includes: taking the pressure value at the moment of descent after the pressure in the lifting cylinder reaches the first fluctuation peak during the process of balancing the lifting force with the pressure generated by the cargo as the static lifting pressure of the lifting cylinder, and multiplying the static lifting pressure by the cross-sectional area of ​​the lifting cylinder to obtain the static lifting pressure.

[0019] In some embodiments, the truck load capacity measurement method further includes the following steps: calculating an initial load capacity value based on the pressure generated by the plurality of suspension cylinders; and calculating the load capacity deviation rate based on the initial load capacity value and the actual mass.

[0020] In some embodiments, the truck load capacity measurement method further includes the following steps: determining whether the load capacity deviation rate is 0 and whether it exceeds a preset allowable deviation rate range; if the load capacity deviation rate is not 0 but does not exceed the allowable deviation rate range, recording the cumulative number of times this situation occurs; when the cumulative number exceeds a preset number threshold, performing load capacity compensation calculation; if the load capacity deviation rate exceeds the allowable deviation range, ending the truck load capacity measurement method.

[0021] In some embodiments, the truck load capacity measurement method further includes the following steps: determining and storing a load capacity compensation coefficient based on the load capacity compensation calculation; and calculating a load capacity correction value based on the initial load capacity value and the load capacity compensation coefficient during the next truck load capacity measurement, and using the load capacity correction value as the load capacity.

[0022] In some embodiments, the truck load capacity measurement method further includes the following steps: determining whether the load capacity compensation coefficient needs to be recalibrated; when it is determined that the load capacity compensation coefficient needs to be recalibrated, loading a counterweight with a preset mass into the truck bed; calculating an initial load capacity value corresponding to the counterweight based on the pressure generated by the plurality of suspension cylinders; calculating a calibration compensation coefficient based on the mass of the counterweight and the initial load capacity value; and updating the stored load capacity compensation coefficient value to the calibration compensation coefficient value.

[0023] Another preferred embodiment of this application provides a truck load capacity measurement system for measuring the load capacity of a truck, the truck including a cargo box, a hydropneumatic suspension system for supporting the cargo box, and a hydraulic lifting system for driving the cargo box to lift. The hydropneumatic suspension system includes a plurality of suspension cylinders, the hydraulic lifting system includes a lifting cylinder, and the cargo box has a drive end and a pivot end oppositely disposed and capable of being raised and lowered by the lifting cylinder; the truck load capacity measurement system includes: a distance calculation module, which, when the cargo box of the truck is loaded with goods, calculates the load capacity based on the pressure generated by the plurality of suspension cylinders, the distance between the plurality of suspension cylinders, etc. The system includes a preset distance between the center of gravity of the cargo and the pivot end of the carriage, and calculates the actual distance between the center of gravity of the cargo and the pivot end of the carriage; a lifting control module, used to control the lifting cylinder to provide lifting force to the carriage and balance the lifting force with the pressure generated by the cargo; a lifting force determination module, used to determine the static lifting pressure during the process of balancing the lifting force with the pressure generated by the cargo; and a load capacity calculation module, used to calculate the mass of the cargo based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end of the carriage, and the distance between the drive end and the pivot end of the carriage.

[0024] Compared to existing technologies, the truck load capacity measurement method and system provided by the above embodiments of the present invention, in addition to using existing hydropneumatic suspension systems for load conversion, also incorporates lifting force and cargo center of gravity offset distance as parameters for calculating load capacity, thereby improving the accuracy and stability of truck load capacity measurement. Furthermore, the truck load capacity measurement method and system can further add lifting feedback as a closed-loop parameter of the load capacity measurement system based on existing hydropneumatic suspension weighing technology. This allows the original open-loop conversion link to obtain a stable and controllable gain coefficient, eliminating large data errors caused by serious malfunctions in the hydropneumatic suspension system and compensating for data offsets caused by minor errors in the hydropneumatic suspension system. This enables the truck load capacity measurement system to achieve autonomous verification, autonomous correction, and autonomous compensation during operation, greatly improving the reliability and stability of load capacity measurement. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram illustrating the principle of a method for measuring the load capacity of a freight truck in the prior art.

[0027] Figure 2 This is a flowchart of the main steps of a truck load capacity measurement method provided by a preferred embodiment of this application.

[0028] Figure 3 yes Figure 2 The diagram illustrates the principle of determining the load capacity of a freight car using the method shown.

[0029] Figure 4 yes Figure 2 The diagram illustrates the principle of determining the axial offset distance of the vehicle's center of gravity using the method shown.

[0030] Figure 5 This is a functional block diagram of a truck load capacity measurement system provided by a preferred embodiment of this application.

[0031] Figure 6 This is a flowchart illustrating the specific steps of another method for measuring the load capacity of a freight truck, provided by a preferred embodiment of this application. Detailed Implementation

[0032] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0033] A preferred embodiment of this application provides a method for measuring the load capacity of a truck. This method is applicable to large trucks. In this embodiment, a common six-wheeled mining dump truck is used as an example, which has six wheels, including two front wheels, two middle wheels, and two rear wheels. According to existing technology, the truck has a cargo box and a hydraulic lifting system for lifting one end of the cargo box for unloading. The hydraulic lifting system includes lifting cylinders. The cargo box has a driving end and a pivot end arranged opposite each other. The driving end is tractively connected to the lifting cylinder and can be raised and lowered under the drive of the lifting cylinder. The pivot end is equipped with a rotating pin. When the lifting cylinder drives the driving end to rise and fall, the cargo box can pivot around the rotating pin, thereby forming the required tilt angle for easy unloading and loading. The truck also has a hydropneumatic suspension system for supporting its cargo box. The hydropneumatic suspension system includes multiple suspension cylinders distributed at different positions on the truck. Specifically, in this embodiment, the number of suspension cylinders is six, corresponding to the number of wheels of the truck, with one suspension cylinder above each wheel. It is understood that the specific structure and working principle of the cargo box, the hydraulic lifting system and its lifting cylinders, and the hydropneumatic suspension system and its suspension cylinders can all refer to existing technologies, and therefore need not be elaborated here. In other embodiments, the truck wheels and suspension cylinders may also have other numbers.

[0034] For ease of description, the following uses the following definitions for the six suspension cylinders: The pressures in the two suspension cylinders located above the two front wheels of the truck are defined as P1 and P4, and the cross-sectional areas of these two cylinders are defined as S1 and S4, respectively; the pressures in the two suspension cylinders located above the two middle wheels of the truck are defined as P2 and P5, and the cross-sectional areas of these two cylinders are defined as S2 and S5, respectively; the pressures in the two suspension cylinders located above the two rear wheels of the truck are defined as P3 and P6, and the cross-sectional areas of these two cylinders are defined as S3 and S6, respectively. Additionally, the pressure in the lifting cylinder is defined as P7, and the cross-sectional area of ​​the lifting cylinder is defined as S7.

[0035] Please see Figure 2 The method includes the following main steps:

[0036] S1, when the cargo is loaded in the cargo compartment of the truck, the actual distance between the center of gravity of the cargo and the pivot end of the cargo compartment is calculated based on the pressure generated by the plurality of suspension cylinders, the distance between the plurality of suspension cylinders, and the preset distance between the center of gravity of the cargo and the pivot end of the cargo compartment.

[0037] Please refer to the following: Figure 3 Step S1 may specifically include the following operations:

[0038] When the truck is loaded with cargo and is stationary or idling, the pressure generated in the multiple suspension cylinders is first acquired, namely, the pressures P1 to P6 defined above. The specific method for acquiring these pressures can be through a pressure sensor system in the prior art, which will not be elaborated here. The pressures in the multiple suspension cylinders are then multiplied by the cross-sectional areas of the corresponding suspension cylinders, namely, the cross-sectional areas S1 to S6 defined above, to obtain the pressures F1 to F6 generated by the multiple suspension cylinders, i.e.: F1 = P1S1; F2 = P2S2; F3 = P3S3; F4 = P4S4; F5 = P5S5; F6 = P6S6.

[0039] In this embodiment, step S1 also requires obtaining and calculating the distance L2 between the suspension cylinders located above the rear wheels and the middle wheels on the same side of the truck, the distance L3 between the suspension cylinders located above the middle wheels and the front wheels on the same side of the truck, and the preset distance x between the center of gravity of the cargo and the pivot end of the truck bed. Clearly, the distances L2, L3, and x can all be constants obtained through actual measurements based on the actual conditions of the truck and cargo (such as truck model, cargo model, cargo placement method, etc.) or directly set, and can be directly used for subsequent calculations.

[0040] Based on the pressures F1 to F6 borne by the multiple suspension cylinders, and the aforementioned distances L2 and L3, the offset distance Δ of the cargo's center of gravity along the length of the truck is calculated, which is... Figure 3 The deviation of the direction of the weight of the cargo G=Mg and the distance along the length of the truck from the pressure (i.e., F3 or F6) generated by the suspension cylinder located above the rear wheels of the truck:

[0041]

[0042] After calculating the offset distance Δ, the actual distance D = x + Δ between the center of mass of the cargo and the pivot end of the carriage is calculated based on the offset distance Δ and the preset distance x between the center of mass of the cargo and the pivot end of the carriage.

[0043] S2, control the lifting cylinder to provide lifting force to the carriage, and balance the lifting force with the pressure generated by the cargo.

[0044] Specifically, when the truck's cargo compartment is loaded with goods and the truck is stationary or idling, the lifting cylinders of the hydraulic lifting system apply a lifting force to the drive end of the cargo compartment. When applying the lifting force, the lifting cylinders are controlled to generate a gradually increasing lifting force from 0 according to a preset lifting force change rate. This prevents the cargo compartment from rapidly tipping over, and instead, under the gradually increasing lifting force, it gradually overcomes the weight of the goods, creating a lifting trend. Please refer to [further details omitted]. Figure 4 When the drive end of the carriage is just about to be lifted, it is considered that the lifting force and the pressure generated by the cargo have reached a balance.

[0045] S3, determining the static lifting pressure during the process of balancing the lifting force with the pressure generated by the cargo.

[0046] Please refer to the following: Figure 4 When the lifting cylinder generates lifting force, it produces a pressure corresponding to the lifting force, which is the pressure P7 defined above. The pressure P7 can be obtained using a pressure sensor system in the prior art, which will not be elaborated here. Furthermore, during the process described in S2 of balancing the lifting force with the pressure generated by the cargo, the pressure P7 in the lifting cylinder will fluctuate to a certain extent. In this embodiment, preferably, the pressure value of P7 at the moment of decline after reaching the first peak fluctuation is taken as the static lifting pressure of the lifting cylinder. This static lifting pressure is multiplied by the cross-sectional area S7 of the lifting cylinder, and the product P7S7 is the static lifting pressure.

[0047] S4. The actual mass of the cargo is calculated as the load capacity based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end of the carriage, and the distance between the drive end and the pivot end of the carriage.

[0048] Please refer to the following: Figure 4 After determining the static lifting pressure (P7 S7) and the actual distance (x+Δ) between the center of gravity of the cargo and the pivot end of the truck bed according to the aforementioned steps S1 to S3, step S4 also requires obtaining the distance L1 between the drive end and the pivot end of the truck bed for calculation. It can be understood that the distance L1 between the drive end and the pivot end of the truck bed is a constant obtained from actual measurements based on the truck model or directly set, and can be directly used for subsequent calculations.

[0049] In this embodiment, based on the static lifting pressure (P7S7), the actual distance (x+Δ) between the center of gravity of the cargo and the pivot end of the carriage, and the distance L1 between the drive end and the pivot end of the carriage, the actual mass M of the cargo is calculated using the following formula:

[0050]

[0051] Where g is the acceleration due to gravity. The calculated actual mass M of the cargo can then be recorded as the load capacity.

[0052] Another preferred embodiment of this application provides a truck load capacity measurement system for measuring the load capacity of the aforementioned truck. Please refer to [link / reference]. Figure 5 The truck load capacity measurement system includes: a distance calculation module, which calculates the actual distance between the center of gravity of the cargo and the pivot end of the truck body when the cargo is loaded in the truck body, based on the pressure generated by the multiple suspension cylinders, the distance between the multiple suspension cylinders, and a preset distance between the center of gravity of the cargo and the pivot end of the truck body; a lifting control module, which controls the lifting cylinders to provide lifting force to the truck body and balances the lifting force with the pressure generated by the cargo; a lifting force determination module, which determines the static lifting pressure during the process of balancing the lifting force with the pressure generated by the cargo; and a load capacity calculation module, which calculates the actual mass of the cargo as the load capacity based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end of the truck body, and the distance between the drive end and the pivot end of the truck body.

[0053] The distance calculation module, lifting control module, lifting force determination module, and load capacity calculation module can be software modules, hardware modules, or a combination of both. In this embodiment, these modules can be entirely installed in the truck. Their software components (if any) can be integrated into the truck's existing central control system according to existing technology, and their hardware components (if any) can also be integrated with the truck's existing hardware structure. Of course, in other embodiments, these modules can also be wholly or partially installed in a data processing device, such as a computer, independent of the truck. Then, they can establish communication with relevant measuring devices inside the truck, such as the aforementioned hydropneumatic suspension system, hydraulic lifting system, and existing cylinder pressure sensor system, through existing wireless or wired communication methods, in order to obtain the data required for measuring the load capacity from the truck.

[0054] In the truck load measurement method and system provided by the preferred embodiments of this application, in addition to using the existing hydropneumatic suspension system to convert the load, lifting force and cargo center offset distance are added as parameters for calculating the load, thereby improving the accuracy and stability of truck load measurement.

[0055] It is understood that steps S1 to S4 of the preferred embodiment of the truck load capacity measurement method described above are merely necessary operational steps to achieve the most basic technical solution of this application. Other embodiments of the truck load capacity measurement method provided in this application may further include more specific operational steps to address problems that may be encountered in practice. For example… Figure 6 As shown, another preferred embodiment of this application provides another method for measuring the load capacity of a truck. The truck can also be a six-wheeled mining dump truck, which includes the same hydropneumatic suspension system, hydraulic lifting system, pressure sensor system, and the truck load capacity measurement system described in the aforementioned embodiments as the truck described above. This truck load capacity measurement method may include the following specific steps:

[0056] S10: Determine whether the truck load capacity measurement system is being powered on for the first time, i.e., whether it is being used for the first time. If the determination result is yes, then proceed to subsequent steps S11 and S12; if the determination result is no, then proceed directly to subsequent step S20.

[0057] S11, If ​​the truck load measurement system is powered on for the first time, set initial operating parameters for the truck load measurement system. The initial operating parameters include truck model, default load parameters (e.g., the distance L2 between the suspension cylinders located above the rear wheels and the suspension cylinders located above the middle wheels on the same side of the truck, the distance L3 between the suspension cylinders located above the middle wheels and the suspension cylinders located above the front wheels on the same side of the truck, the preset distance x between the center of gravity of the cargo and the pivot end of the truck bed, etc.), the cross-sectional area of ​​each suspension cylinder of the hydropneumatic suspension system, the cross-sectional area of ​​the lifting cylinders of the hydraulic lifting system, etc.

[0058] S12, initialize the truck load capacity measurement system according to the initial working parameters set in step S11, and then execute the subsequent step S20.

[0059] S20, determine whether the truck is in a stable state, such as a stationary state or an idling state. The load capacity can only be accurately measured in a stable state.

[0060] S30: If the truck is in a stable state, when the truck bed is loaded with goods, the actual distance between the center of gravity of the goods and the pivot end of the truck bed is calculated based on the pressure generated by the plurality of suspension cylinders, the distance between the plurality of suspension cylinders, and the preset distance between the center of gravity of the goods and the pivot end of the truck bed. This step S30 can correspond to step S1 in the aforementioned method embodiment, and its specific operation can also refer to step S1, which will not be repeated here.

[0061] S40, determine whether the hydraulic lifting system has started lifting the carriage.

[0062] S50, if the hydraulic lifting system has already started lifting the carriage, the lifting cylinder is controlled to provide a lifting force to the carriage, and the lifting force is balanced with the pressure generated by the cargo; during the process of balancing the lifting force with the pressure generated by the cargo, a static lifting pressure is determined; based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end of the carriage, and the distance between the drive end and the pivot end of the carriage, the actual mass of the cargo is calculated as the load capacity. This step S50 can correspond to steps S2, S3, and S4 in the aforementioned method implementation, and its specific operation can also be described in steps S2, S3, and S4, which will not be repeated here.

[0063] Based on the above steps S10 to S50, the actual mass of the cargo carried by the truck bed, i.e. the load capacity, can be measured by following operations similar to steps S1 to S4 of the aforementioned method implementation.

[0064] In addition, in order to further improve the accuracy of measuring load capacity in the method of this embodiment, step S30 may further include the following operations in addition to the operations corresponding to step S1 in the aforementioned method embodiment:

[0065] Based on the pressure generated by the multiple suspension cylinders, the initial load capacity M1 is calculated. Specifically, the initial load capacity can be calculated using the following formula: M1 = (P1S1 + P2S2 + P3S3 + P4S4 + P5S5 + P6S6) / g, where g is the acceleration due to gravity.

[0066] Correspondingly, the truck load capacity measurement method of this embodiment may further include the following steps after step S50:

[0067] S60, calculate the load deviation rate based on the initial load value calculated in step S30 and the load value calculated in step S50.

[0068] Step S60 may include the following operations: the initial load value calculated in step S30 is recorded as M1, the actual mass calculated in step S50 is recorded as M2, and the load deviation rate is recorded as R. The load deviation rate can then be calculated according to the following formula: R = M1 / M2 - 1.

[0069] S70, determine whether the load deviation rate is 0 and whether it exceeds the preset allowable deviation rate range; if the load deviation rate is not 0 but does not exceed the allowable deviation rate range, then continue to execute step S80; if the load deviation rate exceeds the allowable deviation rate range, then continue to execute step S90.

[0070] In this embodiment, since the allowable error value of mainstream pressure weighing systems on the market is ±5%, the allowable deviation rate range is set to [-0.05, 0.05]. That is, when -0.05 ≤ R ≤ 0.05, it is determined that the load deviation rate does not exceed the preset allowable deviation rate range; otherwise, it is determined that the load deviation rate exceeds the preset allowable deviation rate range.

[0071] S80, if the load deviation rate is not 0 but does not exceed the allowable deviation rate range, record the cumulative number of consecutive occurrences of this situation; when the cumulative number of consecutive occurrences of the load deviation rate being not 0 but not exceeding the allowable deviation rate range exceeds a preset threshold (preferably 5 times in this embodiment, but less or more times in other embodiments), it is determined that the internal pressure calibration of the suspension cylinder of the hydropneumatic suspension system is inaccurate or a minor fault has occurred. In order to resolve the errors caused by calibration errors or minor faults, load compensation calculation can be performed. Specifically, the load compensation calculation can be performed by calculating the load compensation coefficient k according to the following formula. α :k α =M1 / M2, then based on the load compensation coefficient k α Determine the load compensation formula: M′1=k α M1, where M′1 represents the compensated load correction value, which compensates for measurement errors caused by pressure fluctuations due to calibration errors or minor malfunctions in the hydropneumatic suspension system. The load compensation coefficient k... α The load is stored in the truck load measurement system. When the truck load is measured again, after the initial load value M1 is measured, the load correction value M′1 can be directly calculated according to the above load compensation formula, and the load correction value M′1 can be directly used as the actual load.

[0072] S90, if the load deviation rate exceeds the allowable deviation rate range, it is determined that the suspension cylinder has a serious mechanical failure and its pressure feedback value cannot be used as the load calculation standard. At this time, the entire method process is terminated directly, and the actual operating status of the suspension cylinder needs to be checked. The method can only be repeated after the fault is eliminated.

[0073] In some embodiments, the load compensation coefficient k is adjusted in step S80. αAfter storage, if the truck load measurement method is executed again, in order to ensure the load compensation coefficient k... α To maintain sufficient accuracy, the truck load capacity measurement method may further include the following steps between steps S10 and S20:

[0074] S13, if the judgment result of step S10 is negative, determine whether the load compensation coefficient needs to be recalibrated.

[0075] S14, when it is determined that the load compensation coefficient needs to be recalibrated, a counterweight with a preset mass M0 is loaded into the cargo compartment of the truck, and the mass M0 of the counterweight is obtained through the truck load measurement system.

[0076] S15, based on the pressure generated by the multiple suspension cylinders, calculate the initial load value M1 corresponding to the counterweight according to the above-mentioned initial load value calculation formula M1=(P1S1+P2S2+P3S3+P4S4+P5S5+P6S6) / g, and then calculate the calibration compensation coefficient k according to the following formula. b :k b =M1 / M0, and the load compensation coefficient k previously stored in the truck load capacity measurement system. α The value is updated to the calibration compensation coefficient k. b The value.

[0077] S16, Store and update the load compensation coefficient k α Then, the truck load capacity measurement system was restarted.

[0078] According to the above technical solution, Figure 6 The preferred embodiment shown provides a truck load capacity measurement method that, in addition to having and Figures 2 to 4 In addition to the beneficial technical effects similar to the truck load measurement method shown, it can further add lifting feedback as a closed-loop parameter of the load measurement system on the basis of the existing hydropneumatic suspension weighing technology. This allows the original open-loop conversion link to obtain a stable and controllable gain coefficient, which can eliminate large data errors caused by serious failures of the hydropneumatic suspension system and compensate for data offsets caused by slight errors of the hydropneumatic suspension system. This enables the truck load measurement system to achieve autonomous verification, autonomous correction, and autonomous compensation during operation, greatly improving the reliability and stability of load measurement.

[0079] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A method for measuring the load capacity of a freight truck, the freight truck comprising a cargo box, a hydropneumatic suspension system for supporting the cargo box, and a hydraulic lifting system for driving the cargo box to lift, the hydropneumatic suspension system comprising a plurality of suspension cylinders, the hydraulic lifting system comprising a lifting cylinder, the cargo box having a drive end and a pivoting end oppositely disposed and capable of being raised and lowered under the drive of the lifting cylinder; characterized in that, The method for measuring the load capacity of a freight car includes the following steps: When the cargo compartment is loaded with cargo, the offset distance of the cargo's center of gravity along the length of the truck is calculated based on the pressure generated by the multiple suspension cylinders and the relative positional relationship between the multiple suspension cylinders; the actual distance between the cargo's center of gravity and the pivot end is calculated based on the offset distance of the cargo's center of gravity along the length of the truck and the preset distance between the cargo's center of gravity and the pivot end. The lifting cylinder is controlled to provide lifting force to the carriage, and the lifting force is balanced with the pressure generated by the cargo. The static lifting pressure is determined during the process of balancing the lifting force with the pressure generated by the cargo. The actual mass of the cargo is calculated as the load capacity based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end, and the distance between the drive end and the pivot end.

2. The method for measuring the load capacity of a truck as described in claim 1, wherein the truck has six wheels, including two front wheels, two middle wheels, and two rear wheels; the number of suspension cylinders is also six, with one suspension cylinder located above each wheel; characterized in that, The formula for calculating the actual distance between the center of gravity of the cargo and the pivot end of the carriage is as follows: ； ； Wherein, P1S1, P2S2, P3S3, P4S4, P5S5, and P6S6 are the pressures generated by the six suspension cylinders, respectively; L2 is the distance between the suspension cylinder located above the rear wheel and the suspension cylinder located above the middle wheel on the same side of the truck; L3 is the distance between the suspension cylinder located above the middle wheel and the suspension cylinder located above the front wheel on the same side of the truck; x is the preset distance between the center of gravity of the cargo and the pivot end of the truck bed; Δ is the offset distance of the center of gravity of the cargo along the length of the truck; and D is the actual distance between the center of gravity of the cargo and the pivot end of the truck bed.

3. The method for measuring the load capacity of a freight car as described in claim 2, characterized in that, The formula for calculating the actual mass of the goods is: ； Where M is the actual mass of the cargo, P7S7 is the static lifting pressure, L1 is the distance between the drive end and the pivot end of the carriage, and g is the gravitational acceleration.

4. The method for measuring the load capacity of a freight car as described in claim 1, characterized in that, The step of controlling the lifting cylinder to provide lifting force to the carriage and balancing the lifting force with the pressure generated by the cargo includes: controlling the lifting cylinder to generate a gradually increasing lifting force from 0 to the drive end according to a preset lifting force change rate, so that the carriage gradually overcomes the weight of the cargo and forms a lifting trend under the drive of the gradually increasing lifting force; when the drive end of the carriage is just about to be lifted, it is considered that the lifting force and the pressure generated by the cargo have reached a balance.

5. The method for measuring the load capacity of a freight car as described in claim 4, characterized in that, Determining the static lifting pressure during the process of balancing the lifting force with the pressure generated by the cargo includes: taking the pressure value at the moment of descent after the first fluctuation peak in the pressure of the lifting cylinder during the process of balancing the lifting force with the pressure generated by the cargo as the static lifting pressure of the lifting cylinder, and multiplying the static lifting pressure by the cross-sectional area of ​​the lifting cylinder to obtain the static lifting pressure.

6. The method for measuring the load capacity of a freight car as described in claim 1, characterized in that, The method for measuring the load capacity of a freight car also includes the following steps: Calculate the initial load capacity based on the pressure generated by the multiple suspension cylinders; The load deviation rate is calculated based on the initial load measurement and the actual mass.

7. The method for measuring the load capacity of a freight car as described in claim 6, characterized in that, The method for measuring the load capacity of a freight car also includes the following steps: Determine whether the load deviation rate is 0 and whether it exceeds the preset allowable deviation rate range; If the load deviation rate is not 0, but does not exceed the allowable deviation rate range, record the cumulative number of times this situation occurs; when the cumulative number exceeds the preset number threshold, perform load compensation calculation. If the load deviation rate exceeds the allowable deviation range, the truck load measurement method shall be terminated.

8. The method for measuring the load capacity of a freight car as described in claim 7, characterized in that, The method for measuring the load capacity of a freight car also includes the following steps: The load compensation coefficient is determined and stored based on the aforementioned load compensation calculation. When the truck load capacity is measured again, the load capacity correction value is calculated based on the initial load capacity value and the load capacity compensation coefficient, and the load capacity correction value is used as the load capacity.

9. The method for measuring the load capacity of a freight car as described in claim 8, characterized in that, The method for measuring the load capacity of a freight car also includes the following steps: Determine whether the load capacity compensation coefficient needs to be recalibrated; When it is determined that the load compensation coefficient needs to be recalibrated, a counterweight with a preset mass is loaded into the carriage. The initial load value corresponding to the counterweight is calculated based on the pressure generated by the multiple suspension cylinders. The calibration compensation coefficient is calculated based on the mass of the counterweight and the initial load value. The stored load compensation coefficient value is then updated to the calibration compensation coefficient value.

10. A truck load capacity measurement system for measuring the load capacity of a truck, the truck comprising a cargo box, a hydropneumatic suspension system for supporting the cargo box, and a hydraulic lifting system for driving the cargo box to lift, the hydropneumatic suspension system comprising a plurality of suspension cylinders, the hydraulic lifting system comprising a lifting cylinder, the cargo box having a drive end and a pivotable end oppositely disposed and capable of being raised and lowered under the drive of the lifting cylinder; characterized in that, The truck load capacity measurement system includes: The distance calculation module calculates the distance along the length of the truck's center of gravity when the truck's cargo compartment is loaded with cargo, based on the pressure generated by the multiple suspension cylinders and the relative positional relationship between the multiple suspension cylinders; and calculates the actual distance between the cargo's center of gravity and the truck's pivot end based on the distance along the length of the truck's center of gravity and the preset distance between the cargo's center of gravity and the pivot end of the truck compartment. The lifting control module is used to control the lifting cylinder to provide lifting force to the carriage and to balance the lifting force with the pressure generated by the cargo. A lifting force determination module is used to determine the static lifting pressure during the process of balancing the lifting force with the pressure generated by the cargo. The load capacity calculation module is used to calculate the mass of the cargo based on the static lifting pressure, the actual distance between the center of gravity of the cargo and the pivot end of the carriage, and the distance between the drive end and the pivot end of the carriage.

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