Method for calculating loading mass of electric vehicle

Abstract

The invention relates to the field of loading mass calculation, in particular to an electric vehicle loading mass calculation method, which comprises the following steps of: when an electric vehicle is in a loading state, acquiring vehicle body angle data of the electric vehicle in a semi-contact state, distributing shared gravity of a single semi-contact wheel, and deducing a transverse gravity component and a longitudinal gravity component; calculating a mass threshold value of loaded goods according to the height of the loading gravity center, constructing a transverse moment balance equation and a longitudinal moment balance equation, establishing a corresponding loading mass equation set, solving a corresponding loading mass, and triggering rollover early warning when the response loading mass exceeds the mass threshold value. Errors are effectively reduced under the complex road condition or the vehicle inclination state, the mass of loaded objects is more accurately calculated, rollover or out of control caused by the fact that the gravity center of the electric vehicle is too high or overloaded is prevented, the change of the loading mass is monitored in real time, abnormal conditions are found in time, a driver is reminded to take measures through an early warning system, and the safety of the electric vehicle is improved. And potential safety risks are avoided.

Description

Technical Field

[0001] The present invention relates to the field of loading mass calculation, and in particular to a method for calculating the loading mass of an electric vehicle. Background Art

[0002] Currently, most electric vehicle load mass measurements rely on static weighing equipment, such as scales. This requires the vehicle to be parked on a scale for weighing. While this method offers high accuracy, it is cumbersome and cannot monitor changes in load mass in real time. Furthermore, scales are limited by their location, making them infeasible for anytime, anywhere weighing.

[0003] In practice, load mass is often estimated by estimating the volume and density of cargo. This method can be subject to significant errors, especially when cargo density is uneven or loading positions are irregular. Furthermore, this estimation method fails to account for dynamic changes in the vehicle during driving, such as vehicle tilt or uneven road conditions.

[0004] Chinese patent application publication number CN112964345A discloses a freight truck weighing system and weighing method, comprising the following steps: S1: data acquisition to obtain a calibration dataset; S2: training a deep neural network model using the calibration dataset to obtain a vehicle load model; S3: inferring and outputting the vehicle cargo mass based on the vehicle load model. This invention addresses the shortcomings of existing on-board load detection, which suffer from low accuracy and poor stability. Based on the vector Yi formed by the mass of the standard weight detected by the inclination sensor and the matrix Xij formed by the corresponding sensor data set, a CNN model is used to derive the vehicle load model. Ultimately, the vehicle's load mass is derived from the vehicle load model, achieving high-precision detection and early warning of vehicle overloads. Compared to traditional detection methods, this detection method is more accurate and comprehensive.

[0005] Chinese patent application publication number CN104568095A discloses a vehicle-mounted weighing method that can conveniently and in real time measure the mass of cargo on board. The vehicle-mounted weighing method comprises the following steps: installing multiple strain gauge sensors on the axle; sequentially installing test bodies at different locations in the vehicle compartment and reading the sensor readings at each installation; constructing a statically indeterminate equation based on the test body mass array, the sensor reading array, and the distribution coefficient array of each sensor, and obtaining the optimal distribution coefficient of each sensor by solving the statically indeterminate equation with the least squares solution; sequentially installing test bodies at any location in the compartment, recording the actual mass of each test body, and reading the corresponding sensor readings at each installation to determine the measurement error for each installation; performing polynomial fitting to determine the relationship between the measurement error and the measured mass, and obtaining the actual cargo mass based on the sum of the measured mass of the actual cargo and the measurement error of the cargo.

[0006] However, the above method has the following problems: it is difficult to accurately measure the load mass under complex road conditions or when the vehicle is tilted, and the error is large, which may cause the vehicle to be overloaded and increase safety risks. Summary of the Invention

[0007] To this end, the present invention provides a method for calculating the loading mass of an electric vehicle to overcome the problem in the prior art that it is difficult to accurately measure the loading mass under complex road conditions or when the vehicle is tilted, resulting in large errors and the possibility of overloading the vehicle and increasing safety risks.

[0008] To achieve the above object, the present invention provides a method for calculating the loading mass of an electric vehicle, comprising:

[0009] Obtaining the vehicle weight of the electric vehicle and collecting vehicle parameters of the electric vehicle, wherein the vehicle parameters include wheelbase and wheel center distance;

[0010] When the electric vehicle is in a loaded state, collecting normal reaction force data generated when the wheels are in contact with the ground, and marking semi-contact wheels;

[0011] Acquiring body angle data of the electric vehicle in a semi-contact state, wherein the body angle data includes lateral angle data and longitudinal angle data;

[0012] Obtaining the weight of the entire vehicle, calculating the gravity of the entire vehicle, determining the loading center of gravity and tilt parameters of the loaded items, allocating the shared gravity of each semi-contact wheel based on the number of semi-contact wheels according to the vehicle body angle data, and deriving the lateral gravity component and the longitudinal gravity component based on the shared gravity;

[0013] Calculating a mass threshold of the loaded cargo according to the height of the loading center of gravity, and constructing a lateral moment balance equation and a longitudinal moment balance equation based on the loading center of gravity according to the lateral gravity component and the longitudinal gravity component;

[0014] Utilizing the lateral moment balance equation and the longitudinal moment balance equation, a corresponding set of loading mass equations is established. The vehicle body weight, the normal reaction force data of the semi-contact wheel, the vehicle body angle data, and the shared gravity are substituted into the set of loading mass equations to solve the corresponding loading mass. In response, when the loading mass exceeds the mass threshold, a rollover warning is triggered.

[0015] Furthermore, the steps of collecting normal reaction force data generated when the wheel contacts the ground and marking the semi-contact wheel include:

[0016] Installing a plurality of force sensors at the wheels of the electric vehicle and calibrating the force sensors;

[0017] When the electric vehicle is in a loaded state, starting the force sensor to record the normal reaction force at the wheel;

[0018] When the normal reaction force data of one or more wheels is lower than the force threshold value, the corresponding wheels are defined as semi-contact wheels.

[0019] Furthermore, the step of obtaining the body angle data of the electric vehicle in the semi-contact state includes:

[0020] Placing a body angle sensor at the center of gravity of the electric vehicle;

[0021] When the electric vehicle is in a semi-contact state, starting the body angle sensor to record body angle data of the electric vehicle;

[0022] Abnormal values ​​in the vehicle body angle data are filtered out according to an abnormal threshold range and output.

[0023] Furthermore, the step of allocating the weight sharing of a single semi-contact wheel based on the number of semi-contact wheels includes:

[0024] Calculating the load sharing ratio of the semi-contact wheels;

[0025] Calculating the shared gravity of a single semi-contact wheel according to the sharing ratio, in combination with the loaded center of gravity and the tilt parameter;

[0026] The shared gravity is vector-synthesized to obtain the lateral gravity component and the longitudinal gravity component of the semi-contact wheel.

[0027] Furthermore, the step of calculating the sharing ratio of the semi-contact wheel includes:

[0028] Calculating the projection area of ​​the electric vehicle in the transverse direction and the longitudinal direction of the vehicle body according to the vehicle body angle data;

[0029] The load sharing ratio of each half-contact wheel is calculated based on the projected area and the load center of gravity.

[0030] Furthermore, the lateral moment balance equation is based on the loading center of gravity as a reference point, and the sum of the normal reaction force of each semi-contact wheel and the lateral distance from the loading center of gravity to the semi-contact wheel is zero in the lateral direction of the vehicle body.

[0031] Furthermore, the longitudinal moment balance equation is based on the loading center of gravity as a reference point, and the sum of the normal reaction force of each semi-contact wheel and the longitudinal distance from the loading center of gravity to the semi-contact wheel is zero in the longitudinal direction of the vehicle body.

[0032] Furthermore, in the lateral direction of the vehicle body, the sum of the lateral components of the normal reaction forces of the semi-contact wheels is equal to the lateral gravity component of the electric vehicle, and in the longitudinal direction of the vehicle body, the sum of the longitudinal components of the normal reaction forces of the semi-contact wheels is equal to the longitudinal gravity component of the electric vehicle.

[0033] Furthermore, the mass threshold is the maximum load mass at which the electric vehicle can travel safely in the semi-contact state.

[0034] Furthermore, the tilt parameters include the tilt angle and roll angle of the electric vehicle.

[0035] Compared with the prior art, the present invention obtains the body angle data of the electric vehicle in a semi-contact state when the electric vehicle is in a loaded state, distributes the shared gravity of a single semi-contact wheel, derives the lateral gravity component and the longitudinal gravity component, calculates the mass threshold of the loaded cargo according to the height of the loading center of gravity, constructs the lateral moment balance equation and the longitudinal moment balance equation, establishes the corresponding loading mass equation group, solves the corresponding loading mass, and triggers a rollover warning in response to the loading mass exceeding the mass threshold, thereby effectively reducing errors in complex road conditions or when the vehicle is tilted, more accurately calculating the mass of the loaded items, and preventing the electric vehicle from rolling over or losing control due to an excessively high center of gravity or overloading. By monitoring the changes in the loading mass in real time, abnormal conditions are discovered in a timely manner, and the driver is reminded to take measures through the early warning system to avoid potential safety risks.

[0036] Furthermore, by installing force sensors and recording the normal reaction force of the wheels, combined with the actual driving status of the vehicle, the load mass can be calculated more accurately, especially in complex road conditions or when the vehicle is tilted, which greatly reduces errors. By accurately identifying semi-contact wheels, the contact status of the wheels can be monitored in real time, better adapting to complex working conditions such as uneven roads and slopes.

[0037] Furthermore, by installing a body angle sensor at the center of gravity of an electric vehicle and recording body angle data in a semi-contact state while filtering out outliers, this method can accurately monitor the vehicle's tilt under complex road conditions, providing reliable data support for vehicle dynamic control and load mass calculation. This not only improves the vehicle's driving stability under complex conditions, but also enhances its safety and intelligence level, and provides an important basis for vehicle cargo transportation management.

[0038] Furthermore, by precisely calculating the shared gravity of the semi-contact wheels and their lateral and longitudinal components, the force state of the vehicle under complex working conditions can be accurately reflected, providing key data support for the vehicle's dynamic balance control and load mass calculation, thereby significantly improving the vehicle's safety and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 The present invention provides a flow chart of a method for calculating the loading mass of an electric vehicle. DETAILED DESCRIPTION

[0040] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention.

[0041] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0042] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside", and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0043] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0044] See also Figure 1 As shown in FIG, it is a flow chart of a method for calculating the loading mass of an electric vehicle according to an embodiment of the present invention, including:

[0045] Step S1, obtaining the vehicle weight of the electric vehicle and collecting vehicle parameters of the electric vehicle, wherein the vehicle parameters include wheelbase and wheel center distance;

[0046] Step S2, when the electric vehicle is in a loaded state, collecting normal reaction force data generated when the wheels are in contact with the ground, and marking the semi-contact wheels;

[0047] Step S3, obtaining body angle data of the electric vehicle in a semi-contact state, wherein the body angle data includes lateral angle data and longitudinal angle data;

[0048] Step S4, obtaining the vehicle weight, calculating the vehicle gravity, determining the loading center of gravity and tilt parameters of the loaded items, allocating the shared gravity of each semi-contact wheel based on the number of semi-contact wheels according to the vehicle body angle data, and deriving the lateral gravity component and the longitudinal gravity component based on the shared gravity;

[0049] Step S5, calculating the mass threshold of the loaded cargo according to the height of the loading center of gravity, and constructing a lateral moment balance equation and a longitudinal moment balance equation based on the loading center of gravity according to the lateral gravity component and the longitudinal gravity component;

[0050] Step S6, using the lateral moment balance equation and the longitudinal moment balance equation, establish the corresponding loading mass equation group, substitute the vehicle body weight, the normal reaction force data of the semi-contact wheel, the vehicle body angle data and the shared gravity into the loading mass equation group, solve the corresponding loading mass, and, in response to the loading mass exceeding the mass threshold, trigger the rollover warning.

[0051] In a specific implementation, in step S5, the specific steps for constructing the lateral moment balance equation are as follows: assuming that the loaded center of gravity of the electric vehicle is located at the center of the vehicle body, the lateral distances between the wheels and the loaded center of gravity are L1, L2, L3, and L4, respectively, and the normal reaction forces of each half-contact wheel are F1, F2, F3, and F4, respectively. Then, the lateral moment balance equation can be expressed as: F1×L1 + F2×L2 + F3×L3 + F4×L4 = 0. A specific embodiment for constructing the longitudinal moment balance equation is as follows: assuming that the loaded center of gravity of the electric vehicle is located at the center of the vehicle body, the longitudinal distances between the wheels and the loaded center of gravity are d1, d2, d3, and d4, respectively, and the normal reaction forces of each half-contact wheel are F1, F2, F3, and F4, respectively. Then, the longitudinal moment balance equation can be expressed as: F1×d1 + F2×d2 +F3×d3 + F4×d4 = 0.

[0052] In step S6, the specific steps of establishing the loading mass equation group are as follows: assuming that the vehicle body weight of the electric vehicle is G0, the normal reaction force data of the semi-contact wheels are F1, F2, F3, and F4, and the shared gravity is F, according to the above-mentioned lateral moment balance equation and longitudinal moment balance equation, combined with the vehicle body weight, normal reaction force data, vehicle body angle data, and shared gravity, the following loading mass equation group can be established:

[0053] F1×L1 + F2×L2 + F3×L3 + F4×L4 = 0

[0054] F1×d1 + F2×d2 + F3×d3 + F4×d4 = 0

[0055] G0 + F1 + F2 + F3 + F4 = Total load mass

[0056] By solving the above equations, the corresponding loading mass can be obtained.

[0057] In detail, a representative electric vehicle was selected as the experimental object. The main parameters of the vehicle are as follows:

[0058] Vehicle weight: 1500kg

[0059] Wheelbase: 2800mm

[0060] Wheel center distance: 1500mm

[0061] Vehicle rated load capacity: 3000kg;

[0062] A high-precision force sensor (with an accuracy of ±0.1N) is installed at each wheel of the vehicle and calibrated. At the same time, a high-precision body angle sensor (with an accuracy of ±0.1°) is installed at the vehicle's center of gravity to monitor the vehicle's lateral and longitudinal angles in real time.

[0063] Experiments were conducted under different road conditions, including flat roads, uneven roads (simulating the complex road conditions of actual mine roads), and slopes (with slopes of 5°, 10°, and 15°).

[0064] First, the vehicle is placed on a flat surface and weighed unladen using a traditional static weighing device (such as a floor scale). The unladen weight is recorded as the baseline value. Next, the vehicle's compartment is loaded with cargo of varying weights (500kg, 1500kg, and 3000kg). The total weight after each loading is measured using a traditional static weighing device and recorded as the actual loaded weight.

[0065] Next, the vehicle is started and driven under different road conditions. The normal reaction force data and body angle data of the vehicle are collected in real time through the installed sensors, and the loading mass after each loading is calculated according to the method of the present application.

[0066] Finally, the load mass calculated by the method of the present application is compared with the actual load weight measured by the traditional static weighing equipment to calculate the error.

[0067] When the loading mass is 500Kg and the actual weight is 2000Kg, the error of the traditional method is 5.2%, and the error of the method of this application is 1.3%; when the loading mass is 1500Kg and the actual weight is 3000Kg, the error of the traditional method is 7.0%, and the error of the method of this application is 2.1%; when the loading mass is 3000Kg and the actual weight is 4500Kg, the error of the traditional method is 11.0%, and the error of the method of this application is 3.5%.

[0068] In summary, the method of the present application significantly reduces the error in calculating the loading mass.

[0069] By obtaining the body angle data of the electric vehicle in a semi-contact state when the electric vehicle is in a loaded state, the shared gravity of a single semi-contact wheel is allocated, the lateral gravity component and the longitudinal gravity component are derived, and the mass threshold of the loaded cargo is calculated according to the height of the loading center of gravity. The lateral moment balance equation and the longitudinal moment balance equation are constructed, and the corresponding loading mass equation group is established. The corresponding loading mass is solved, and a rollover warning is triggered in response to the loading mass exceeding the mass threshold. This effectively reduces errors in complex road conditions or when the vehicle is tilted, more accurately calculates the mass of the loaded items, and prevents the electric vehicle from rolling over or losing control due to an excessively high center of gravity or overloading. By monitoring the changes in the loading mass in real time, abnormal situations are discovered in a timely manner, and the early warning system reminds the driver to take measures to avoid potential safety risks.

[0070] Specifically, the steps of collecting normal reaction force data generated when the wheel contacts the ground and marking the semi-contact wheel include:

[0071] Installing several force sensors at the wheels of the electric vehicle and calibrating the force sensors;

[0072] When the electric vehicle is in a loaded state, the force sensor is activated to record the normal reaction force at the wheel;

[0073] When the normal reaction force data of one or more wheels is lower than the force threshold value, the corresponding wheels are defined as semi-contact wheels.

[0074] In a specific implementation, several force sensors are installed at each wheel of an electric vehicle. These force sensors can be mounted at the connection between the wheel and the suspension system or directly on the wheel hub. The choice of sensor should be determined by the specific vehicle design and the expected accuracy requirements. The sensor installation position should ensure accurate measurement of the normal reaction force when the wheel contacts the ground.

[0075] After installation, the force sensor is calibrated. The calibration process typically includes the following steps:

[0076] Place the vehicle on flat, level ground, ensuring that the wheels are in full contact with the ground.

[0077] Start the force sensor and record the normal reaction force data at the wheel.

[0078] This data is compared with the known unladen weight of the vehicle and the force sensor output is adjusted to match the actual value.

[0079] Repeat the above steps several times to ensure the calibration accuracy of the sensor.

[0080] In the specific implementation, an electric car was selected as the experimental object, and its main parameters are as follows:

[0081] Vehicle weight: 1500kg

[0082] Wheelbase: 2800mm

[0083] Wheel center distance: 1500mm

[0084] Vehicle rated load capacity: 3000kg;

[0085] A high-precision force sensor (with an accuracy of ±0.1N) is installed and calibrated at each wheel of the vehicle. The force sensor is installed at the connection between the wheel and the suspension system to ensure accurate measurement of the normal reaction force when the wheel contacts the ground.

[0086] Experiments were conducted under different road conditions, including flat roads, uneven roads (simulating the complex road conditions of actual mine roads, including stones, potholes, etc.), and slopes (with slopes of 5°, 10°, and 15°).

[0087] Under various driving conditions, the normal reaction force data of the wheel are as follows:

[0088] On a flat road, the minimum normal reaction force of the wheel is 1480N.

[0089] On uneven roads, the minimum normal reaction force of the wheel is 450N.

[0090] On a 5° slope, the minimum normal reaction force of the wheel is 800N.

[0091] On a 10° slope, the minimum normal reaction force of the wheel is 650N.

[0092] On a 15° slope, the minimum normal reaction force of the wheel is 500N.

[0093] Set a force threshold. This force threshold is determined based on the vehicle's actual usage scenario. For example, through experimental testing and simulation analysis, it was found that the minimum normal reaction force of the wheel under various driving conditions is 500N. To ensure vehicle safety and stability, the force threshold can be set to 400N. In this way, when the normal reaction force of the wheel is less than 400N, the wheel is identified as a semi-contact wheel, and appropriate control measures are taken.

[0094] By installing force sensors and recording the normal reaction force of the wheels, combined with the actual driving status of the vehicle, the load mass can be calculated more accurately, especially in complex road conditions or when the vehicle is tilted, which greatly reduces errors. By accurately identifying semi-contact wheels, the contact status of the wheels can be monitored in real time, better adapting to complex working conditions such as uneven roads and slopes.

[0095] Specifically, the steps of obtaining the body angle data of the electric vehicle in the semi-contact state include:

[0096] Place the body angle sensor at the center of gravity of the electric vehicle;

[0097] When the electric vehicle is in a semi-contact state, the body angle sensor is activated to record the body angle data of the electric vehicle;

[0098] Filter outliers in the vehicle body angle data according to the abnormal threshold range and output them.

[0099] In practice, a high-precision body angle sensor is selected and installed at the center of gravity of the electric vehicle. The center of gravity is the vehicle's geometric center or center of mass, which can be determined using vehicle design parameters or experimental measurements. During installation, ensure the sensor is securely mounted to prevent loosening or displacement due to vibration or impact during driving. Furthermore, the sensor's mounting orientation should align with the vehicle's coordinate system to accurately measure the vehicle's lateral and longitudinal angles.

[0100] When the vehicle is started, the body angle sensor is initialized and calibrated. This involves placing the vehicle on level ground and recording the sensor's initial output value, which serves as the reference zero point. When the electric vehicle is in a semi-contact state (such as when the wheel is partially suspended or the road surface is uneven), the body angle sensor is activated to record the vehicle's lateral and longitudinal angle data in real time. The sensor sampling frequency is determined by the vehicle's actual usage scenario and control requirements, typically between 10 and 100 Hz.

[0101] Based on the vehicle's design parameters and actual usage scenarios, set the abnormality threshold range for body angle data. For example, the abnormality threshold for lateral angle is ±10°, and the abnormality threshold for longitudinal angle is ±5°. These abnormal data are caused by sensor failure, severe vehicle vibration, or external interference.

[0102] The abnormal thresholds for lateral angles are set at ±10°, and for longitudinal angles at ±5°. This is based on the following analysis: Analysis of driving data from a large number of electric vehicles under various road conditions revealed that when the lateral angle of the vehicle body exceeds ±10° or the longitudinal angle exceeds ±5°, the vehicle's driving stability is significantly affected, and the likelihood of an abnormality is high. Therefore, to ensure vehicle safety and stability, the abnormal thresholds for lateral angles are set at ±10°, and for longitudinal angles at ±5°. When vehicle angle data exceeds these thresholds, it is considered abnormal and processed accordingly.

[0103] In this application document, the longitudinal direction refers to the vehicle's Y-axis, which is the front-to-back direction. During the installation and data measurement process of the body angle sensor, the vehicle's Y-axis is used as the longitudinal reference direction to ensure the accuracy and consistency of the body angle data.

[0104] For example, suppose an electric car is driving on an uneven mountain road. Some wheels may be partially suspended due to the uneven road surface, causing the vehicle to tilt. The following steps are used to collect and process the body angle data:

[0105] A body angle sensor composed of a high-precision three-axis acceleration sensor and a gyroscope is installed at the center of gravity of the vehicle.

[0106] In the specific implementation, an electric car was selected as the experimental object, and its main parameters are as follows:

[0107] Vehicle weight: 1500kg

[0108] Wheelbase: 2800mm

[0109] Wheel center distance: 1500mm

[0110] Vehicle rated load capacity: 3000kg;

[0111] A high-precision force sensor (with an accuracy of ±0.1N) is installed at each wheel of the vehicle and calibrated. At the same time, a high-precision body angle sensor (with an accuracy of ±0.1°) is installed at the vehicle's center of gravity to monitor the vehicle's lateral and longitudinal angles in real time.

[0112] Experiments were conducted under different road conditions, including flat roads, uneven roads (simulating the complex road conditions of actual mine roads), and slopes (with slopes of 5°, 10°, and 15°).

[0113] First, place the vehicle on a flat road and use traditional static weighing equipment (such as a floor scale) to weigh the vehicle without load, and record the vehicle's unloaded weight as the baseline value.

[0114] Then, cargo of different weights (500kg, 1000kg, 1500kg, 2000kg, 2500kg, and 3000kg) was loaded into the vehicle compartment in sequence, and the total weight after each loading was measured using traditional static weighing equipment and recorded as the actual loaded weight.

[0115] Next, the vehicle is started and driven under different road conditions. The normal reaction force data and body angle data of the vehicle are collected in real time through the installed sensors, and the loading mass after each loading is calculated according to the method of the present application.

[0116] Finally, the load mass calculated by the method of the present application is compared with the actual load weight measured by the traditional static weighing equipment to calculate the error.

[0117] Assuming that the geometric center of the vehicle is located at the center of mass of the vehicle, the center of gravity of the vehicle's own weight is determined to be (1.4m, 0.7m) through the vehicle design parameters.

[0118] Cargo center of gravity: The center of gravity of the cargo is calculated using a weighted average method based on the loading position and weight of the cargo. For example, when the loading weight is 500kg, the center of gravity of the cargo is (1.2m, 0.6m).

[0119] Vehicle Center of Gravity: This is calculated by combining the vehicle's own center of gravity and the cargo's center of gravity. For example, when the load is 500kg, the center of gravity is (1.3m, 0.65m).

[0120] Calculation of the burden sharing ratio of semi-contact wheels:

[0121] Projected Area Calculation: Calculate the vehicle's projected area in both the lateral and longitudinal directions based on the vehicle body angle data. For example, with a lateral tilt angle of 10° and a longitudinal tilt angle of 5°, and vehicle dimensions of 1.5m in height, 4m in length, and 2m in width, the calculated lateral projected area is approximately 5.98 square meters, and the longitudinal projected area is approximately 2.95 square meters.

[0122] Calculation of load sharing ratio: The load sharing ratio of each semi-contact wheel is calculated based on the projected area and the center of gravity position of the vehicle. For example, when a vehicle is driving on a slope with two semi-contact wheels, the load sharing ratio of each semi-contact wheel is calculated to be 0.5 based on the center of gravity position and projected area.

[0123] Through the above experimental data and calculation process, we can determine the vehicle's center of gravity position and the load-sharing ratio of the semi-contact wheels under different load weights and road conditions. For example, when the load is 500kg, the center of gravity of the vehicle is located at (1.3m, 0.65m), the horizontal projected area is approximately 5.98 square meters, and the longitudinal projected area is approximately 2.95 square meters. The load-sharing ratio of each semi-contact wheel is 0.5.

[0124] Ensure that the sensor's installation orientation is consistent with the vehicle's coordinate system, that is, the sensor's X-axis points to the front of the vehicle, the Y-axis points to the left of the vehicle, and the Z-axis is perpendicular to the vehicle plane.

[0125] When the vehicle is started, the sensor is initialized and calibrated to record the initial angle value of the vehicle on the horizontal ground.

[0126] When the vehicle is driving on a mountain road, the sensor collects the lateral angle (roll angle) and longitudinal angle (pitch angle) data of the vehicle body in real time and transmits the data to the vehicle control system at a frequency of 50Hz.

[0127] The abnormal threshold for the horizontal angle is set to ±10°, and the abnormal threshold for the vertical angle is set to ±5°.

[0128] The collected data is analyzed by an algorithm to identify and filter out data points that exceed an outlier threshold. For example, if a data point has a lateral angle of 12°, it is marked as an outlier and filtered out.

[0129] By installing a body angle sensor at the center of gravity of an electric vehicle, recording body angle data in a semi-contact state, and filtering out outliers, this method can accurately monitor the vehicle's tilt under complex road conditions, providing reliable data support for vehicle dynamic control and load mass calculation. This not only improves vehicle driving stability in complex conditions, but also enhances vehicle safety and intelligence, and provides an important basis for vehicle cargo transportation management.

[0130] Specifically, the step of allocating the weight sharing of a single semi-contact wheel based on the number of semi-contact wheels includes:

[0131] Calculate the load sharing ratio of semi-contact wheels;

[0132] Calculate the shared gravity of a single semi-contact wheel based on the sharing ratio, combined with the loading center of gravity and tilt parameters;

[0133] The shared gravity is vector-synthesized to obtain the lateral gravity component and longitudinal gravity component of the semi-contact wheel.

[0134] In a specific implementation, if an electric vehicle has two semi-contact wheels, the sharing ratio is 0.5.

[0135] The position of the load center of gravity and the vehicle's tilt parameters (such as lateral tilt angle and longitudinal tilt angle) have a significant impact on the weight sharing of the semi-contact wheels. These parameters are obtained through body angle sensors and vehicle design parameters.

[0136] Among them, shared gravity = total gravity × sharing ratio × distance from center of gravity to semi-contact wheel, total gravity is the total weight of the vehicle multiplied by the acceleration of gravity, and the distance from center of gravity to semi-contact wheel can be determined by vehicle design parameters.

[0137] For example, assume a four-wheeled electric vehicle is traveling on a slope, with two wheels in semi-contact. Calculate the weight share and its components of the semi-contact wheels using the following steps:

[0138] The number of semi-contact wheels is 2 and the total number of wheels is 4, so the sharing ratio is 0.5.

[0139] Assume that the total weight of the vehicle is 1500 kg and the distance from the center of gravity to the semi-contact wheel is 1.5 m.

[0140] The total gravity is 1500×9.8=14700N.

[0141] The shared gravity is 14700×0.5×1.5=11025N.

[0142] Assume that the lateral tilt angle is 10° and the longitudinal tilt angle is 5°.

[0143] The lateral gravity component is 11025×sin(10°)=1913N.

[0144] The longitudinal gravity component is 11025×sin(5°)=956N.

[0145] The lateral and longitudinal gravity components of the two semi-contact wheels are vector-synthesized to obtain a total lateral gravity component of 2×1913=3826N and a total longitudinal gravity component of 2×956=1912N.

[0146] By precisely calculating the shared gravity of the semi-contact wheels and its lateral and longitudinal components, the force state of the vehicle under complex working conditions can be accurately reflected, providing key data support for the vehicle's dynamic balance control and load mass calculation, thereby significantly improving the vehicle's safety and stability.

[0147] Specifically, the steps for calculating the sharing ratio of the semi-contact wheel include:

[0148] Calculate the projection area of ​​the electric vehicle in the transverse and longitudinal directions of the vehicle body based on the vehicle body angle data;

[0149] Based on the projected area and the loaded center of gravity, calculate the sharing ratio of each half of the contacting wheel.

[0150] In a specific implementation, assume an electric vehicle is traveling on a slope with a lateral inclination angle of 10° and a longitudinal inclination angle of 5°. The vehicle dimensions are: height H = 1.5m, length L = 4m, and width W = 2m. The vehicle has two semi-contact wheels, located at (x = 1m, y = 0.5m) and (x = 3m, y = 1.5m), respectively. The calculated load center of gravity is (x = 1.5m, y = 0.8m). Based on the lateral and longitudinal inclination angles of the electric vehicle, the calculated lateral projected area is 4 × 1.5 × cos(5°) ≈ 5.98 square meters, and the longitudinal projected area is 2 × 1.5 × cos(10°) ≈ 2.95 square meters. Therefore, the load sharing ratio for the first semi-contact wheel is 0.5, and the load sharing ratio for the second semi-contact wheel is 0.5.

[0151] Specifically, the lateral moment balance equation is that the sum of the normal reaction force of each semi-contact wheel and the lateral distance from the loading center of gravity to the semi-contact wheel is zero in the lateral direction of the vehicle body, with the loading center of gravity as the reference point.

[0152] Specifically, the longitudinal moment balance equation is that the sum of the normal reaction force of each semi-contact wheel and the longitudinal distance from the loading center of gravity to the semi-contact wheel is zero in the longitudinal direction of the vehicle body, with the loading center of gravity as the reference point.

[0153] Specifically, in the lateral direction of the vehicle body, the sum of the lateral components of the normal reaction forces of the semi-contact wheels is equal to the lateral gravity component of the electric vehicle, and in the longitudinal direction of the vehicle body, the sum of the longitudinal components of the normal reaction forces of the semi-contact wheels is equal to the longitudinal gravity component of the electric vehicle.

[0154] In practice, the purpose of the lateral and longitudinal moment balance equations is to ensure that the vehicle maintains moment balance in the lateral and longitudinal directions, preventing the vehicle from rolling. These equations accurately calculate and adjust the force distribution on the vehicle, ensuring good dynamic balance in complex operating conditions (such as slopes and uneven roads), preventing roll or pitch imbalances.

[0155] Specifically, the mass threshold is the maximum load mass that an electric vehicle can safely travel in a semi-contact state.

[0156] Specifically, the tilt parameters include the tilt angle and roll angle of the electric vehicle.

[0157] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

[0158] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for calculating the loading mass of an electric vehicle, characterized in that: A coordinate system is established with the center of gravity of the electric vehicle as the origin. The horizontal axis represents the lateral direction of the vehicle body, and the vertical axis represents the longitudinal direction of the vehicle body, including: Obtaining the vehicle weight of the electric vehicle and collecting vehicle parameters of the electric vehicle, wherein the vehicle parameters include wheelbase and wheel center distance; When the electric vehicle is in a loaded state, collecting normal reaction force data generated when the wheels are in contact with the ground, and marking semi-contact wheels; Acquiring body angle data of the electric vehicle in a semi-contact state, wherein the body angle data includes lateral angle data and longitudinal angle data; Obtaining the weight of the entire vehicle, calculating the gravity of the entire vehicle, determining the loading center of gravity and tilt parameters of the loaded items, allocating the shared gravity of each semi-contact wheel based on the number of semi-contact wheels according to the vehicle body angle data, and deriving the lateral gravity component and the longitudinal gravity component based on the shared gravity; Calculating a mass threshold of the loaded cargo according to the height of the loading center of gravity, and constructing a lateral moment balance equation and a longitudinal moment balance equation based on the loading center of gravity according to the lateral gravity component and the longitudinal gravity component; Utilizing the lateral moment balance equation and the longitudinal moment balance equation, a corresponding set of loading mass equations is established. The vehicle body weight, the normal reaction force data of the semi-contact wheel, the vehicle body angle data, and the shared gravity are substituted into the set of loading mass equations to solve the corresponding loading mass. In response, when the loading mass exceeds the mass threshold, a rollover warning is triggered.

2. The electric vehicle loading mass calculation method according to claim 1, characterized in that: The steps of collecting normal reaction force data generated when the wheel contacts the ground and marking the semi-contact wheel include: Installing a plurality of force sensors at the wheels of the electric vehicle and calibrating the force sensors; When the electric vehicle is in a loaded state, starting the force sensor to record the normal reaction force at the wheel; When the normal reaction force data of one or more wheels is lower than the force threshold value, the corresponding wheels are defined as semi-contact wheels.

3. The electric vehicle loading mass calculation method according to claim 2, characterized in that: The steps of obtaining the body angle data of the electric vehicle in the semi-contact state include: Placing a body angle sensor at the center of gravity of the electric vehicle; When the electric vehicle is in a semi-contact state, starting the body angle sensor to record body angle data of the electric vehicle; Abnormal values ​​in the vehicle body angle data are filtered out according to an abnormal threshold range and output.

4. The electric vehicle loading mass calculation method according to claim 3, characterized in that: The steps of allocating the weight sharing of a single semi-contact wheel based on the number of semi-contact wheels include: Calculating the load sharing ratio of the semi-contact wheels; Calculating the shared gravity of a single semi-contact wheel according to the sharing ratio, in combination with the loaded center of gravity and the tilt parameter; The shared gravity is vector-synthesized to obtain the lateral gravity component and the longitudinal gravity component of the semi-contact wheel.

5. The electric vehicle loading mass calculation method according to claim 4, characterized in that: The steps for calculating the contribution ratio of semi-contact wheels include: Calculating the projection area of ​​the electric vehicle in the transverse direction and the longitudinal direction of the vehicle body according to the vehicle body angle data; The load sharing ratio of each half-contact wheel is calculated based on the projected area and the load center of gravity.

6. The method for calculating the loading mass of an electric vehicle according to claim 5, characterized in that: The lateral moment balance equation is based on the loading center of gravity as a reference point, and the sum of the normal reaction force of each semi-contact wheel and the lateral distance from the loading center of gravity to the semi-contact wheel is zero in the lateral direction of the vehicle body.

7. The method for calculating the loading mass of an electric vehicle according to claim 6, characterized in that: The longitudinal moment balance equation is based on the loading center of gravity as a reference point, and the sum of the normal reaction force of each semi-contact wheel and the longitudinal distance from the loading center of gravity to the semi-contact wheel is zero in the longitudinal direction of the vehicle body.

8. The method for calculating the loading mass of an electric vehicle according to claim 7, characterized in that: In the lateral direction of the vehicle body, the sum of the lateral components of the normal reaction forces of the semi-contact wheels is equal to the lateral gravity component of the electric vehicle, and in the longitudinal direction of the vehicle body, the sum of the longitudinal components of the normal reaction forces of the semi-contact wheels is equal to the longitudinal gravity component of the electric vehicle.

9. The method for calculating the loading mass of an electric vehicle according to claim 8, characterized in that: The mass threshold is the maximum load mass on which the electric vehicle can travel safely in the semi-contact state.

10. The electric vehicle loading mass calculation method according to claim 9, characterized in that: The tilt parameters include the tilt angle and the roll angle of the electric vehicle.

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