CN111695197B - Highly-reliable dynamic estimation method for rollover threshold value of tank car - Google Patents

Highly-reliable dynamic estimation method for rollover threshold value of tank car Download PDF

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CN111695197B
CN111695197B CN202010444574.3A CN202010444574A CN111695197B CN 111695197 B CN111695197 B CN 111695197B CN 202010444574 A CN202010444574 A CN 202010444574A CN 111695197 B CN111695197 B CN 111695197B
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rollover
test
tank car
threshold
air bag
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CN111695197A (en
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李旭
韦坤
徐启敏
倪培洲
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Southeast University
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    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00Computer-aided design [CAD]
    • G06F30/10Geometric CAD
    • G06F30/15Vehicle, aircraft or watercraft design
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01MTESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M17/00Testing of vehicles
    • G01M17/007Wheeled or endless-tracked vehicles
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/02Reliability analysis or reliability optimisation; Failure analysis, e.g. worst case scenario performance, failure mode and effects analysis [FMEA]
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14Force analysis or force optimisation, e.g. static or dynamic forces

Abstract

The invention provides a highly reliable dynamic estimation method for a tank car rollover threshold value. The method provides a rollover characterization parameter of the lateral transfer rate of the air bag pressure, and meets the requirement of rollover risk redundancy judgment; the tank car rollover threshold calibration device is constructed by utilizing the high-precision inertia measurement unit, the pressure sensor, the wheel force sensor and the rollover prevention frame, and can be applied to a real-vehicle test; and fitting a functional relation between the rollover threshold and the influence factors thereof through real vehicle test data and the SVR to realize dynamic estimation of the rollover threshold.

Description

Highly-reliable dynamic estimation method for rollover threshold value of tank car
Technical Field
The invention relates to a rollover threshold value estimation method, in particular to a highly reliable dynamic estimation method for a rollover threshold value of a tank car, and belongs to the technical field of vehicle safety.
Background
The dangerous goods transportation safety situation in China is severe, and rollover is one of the main accident forms. Due to the large loading capacity and high transportation efficiency, the tank truck is a main carrier for road transportation of dangerous goods. However, the whole tank truck has large mass and high mass center and is disturbed by liquid, so that the tank truck is easy to turn on one side when turning and changing lanes, dangerous goods are leaked, burnt and exploded, and property loss, environmental pollution, ecological damage and casualties are caused. Therefore, the research on the tank car rollover prevention and control method has important significance on road safety.
At present, a rollover prevention and control method is based on a fixed rollover threshold value, such as lateral acceleration of 0.4g, and the like, however, the rollover threshold value of a tank truck is dynamically changed under different driving behaviors, different liquid filling ratios and different road slopes, so that the single fixed rollover threshold value is difficult to adapt to the actual rollover prevention and control requirements of the tank truck. According to data research, the acquisition way of the tank car rollover threshold value is mainly based on a multidimensional simulation test, and the reasons are as follows: 1. the method is lack of a highly reliable calibration device for the rollover threshold value of the tank car, 2, a typical rollover scene library suitable for the tank car, and 3, a method capable of dynamically estimating the rollover threshold value according to the running condition of the tank car.
Disclosure of Invention
The invention provides a highly reliable dynamic estimation method for a tank car rollover threshold value, aiming at the problem that a single fixed rollover threshold value is difficult to meet the actual rollover prevention and control requirements of a tank car. The method can dynamically estimate the rollover threshold value according to the current driving state of the tank car, and is beneficial to improving the accuracy of rollover early warning.
In order to achieve the above purpose, the invention provides the following technical scheme:
the method comprises the following steps: side turning characteristic parameters and factors influencing a side turning threshold are determined and a side turning threshold calibration device is built
The rollover characterizing parameters are selected as a side inclination angle tau, a lateral acceleration theta and an air bag pressure transverse transfer rate eta, factors influencing the rollover threshold value of the tank car are selected as a vehicle speed v, a whole vehicle mass m and a liquid filling ratio lambda, and the eta calculation formula is as follows:
Figure BDA0002505277430000021
in the formula (1), F ls Is the pressure of the left air bag of the s-th axle of the tank car, F rs The pressure of an air bag at the right side of the s th axle of the tank car, s is the number of the axles, s =1,2, …, e, e is the total number of the axles of the tank car;
the rollover threshold value calibration device comprises a high-precision inertia measurement unit, a plurality of pressure sensors, two wheel force sensors and two rollover prevention frames, wherein the high-precision inertia measurement unit is arranged close to the center of mass of the tank car; the high-precision inertial measurement unit acquires a roll angle tau and a lateral acceleration theta, and the wheel force sensor acquires a vertical force G of a left wheel of a final shaft l Vertical force of right wheelG r Acquiring the average value of information of two wheel speed sensors on a last shaft through a vehicle body CAN bus as a vehicle speed v, wherein the data output frequencies of the sensors are the same, and the vehicle mass m and the liquid filling ratio lambda are obtained by static measurement in advance;
step two: tank car rollover threshold calibration test under typical rollover scene developed in closed test site
The division of each scene element of the tank car rollover scene library is shown as the following table:
Figure BDA0002505277430000022
after the scene elements are arranged and combined, 30 rollover scenes exist; the tank truck rollover threshold calibration test under a typical rollover scene specifically comprises the following steps:
substep 1: the calibration test is carried out on a dry and solid road surface, and the peak value adhesion coefficient of the road surface is not less than 0.9; checking the reliability of each sensor in the calibration device, the safety of the anti-rollover frame and whether potential safety hazards exist in a checking test field;
substep 2: sequentially setting driving behaviors, liquid filling ratios and longitudinal gradients in a closed test field based on the determined rollover scene, drawing test tracks of J steering and double shifting lines on the test field, and statically measuring the mass m and the liquid filling ratio lambda of the whole vehicle before the test is started;
substep 3: keeping constant vehicle speed and running according to a track, taking 32km/h as initial speed, gradually increasing by 2km/h until the vertical force of the tire at the side of the final shaft is 0 in the continuous 5-time test process or the side of the rollover prevention support lands, finishing the rollover threshold calibration test in the current scene, and storing the 5-time test roll angle tau, the lateral acceleration theta, the air bag pressure lateral transfer rate eta, the vehicle speed v, the whole vehicle mass m, the liquid filling ratio lambda and the vertical force G of the left wheel of the final shaft l Last right wheel vertical force G r The data of (a);
substep 4: repeating the substep 2 and the substep 3, completing threshold value calibration tests under 30 rollover scenes and storing data;
step three: processing data and dynamically calibrating rollover thresholds in different typical rollover scenarios
After 30 rollover scene calibration tests are completed, 5 times of test data are stored in each scene, and 150 times of test data are stored in total; adopting weighted mean filtering to collect the roll angle tau, the lateral acceleration theta, the air bag pressure transverse transfer rate eta, the vehicle speed v and the vertical force G of the left wheel of the final axle in each test l Last right wheel vertical force G r Processing the data; take lateral acceleration as an example, θ t For a group of data of the lateral acceleration in a certain test, t =1,2, …, c, c is the data quantity of the lateral acceleration in the test, and the weighted mean filtering processing method is as follows:
when t =1 and t = c,
Figure BDA0002505277430000031
when t =2 and t = c-1,
Figure BDA0002505277430000032
when t is more than or equal to 3 and less than or equal to c-2,
Figure BDA0002505277430000033
the lateral inclination angle tau, the air bag pressure lateral transfer rate eta, the vehicle speed v and the vertical force G of the left wheel of the final axle of the test l Last right wheel vertical force G r Carrying out filtering processing on the data by the same method;
after the data of each item of 150 tests are processed by the method, the roll state H is calculated, and the formula is as follows:
Figure BDA0002505277430000034
in the formula (2), the reaction mixture is,
Figure BDA0002505277430000035
is the vertical force of the left wheel of the last axle subjected to weighted mean filtering processing>
Figure BDA0002505277430000036
The method comprises the following steps of calibrating a rollover threshold value for the vertical force of the right wheel of the last axle after weighted mean filtering treatment by using the side-tipping state H of the tank car, and specifically comprises the following steps:
substep 1: uniformly displaying the data of the roll angle, the lateral acceleration, the transverse transfer rate of the air bag pressure, the vehicle speed and the roll state of a certain test on a time axis, namely the curves of all the data have the same starting time and ending time; the whole vehicle mass and the liquid filling ratio in the test are constant values;
substep 2: searching a point at which the value H of the side-tipping state reaches 0.9 for the first time from the initial moment, recording values of the vehicle speed, the vehicle mass, the liquid filling ratio, the side-tipping angle, the lateral acceleration and the air bag pressure transverse transfer rate at the time, and recording the values as
Figure BDA0002505277430000041
Wherein->
Figure BDA0002505277430000042
The rollover threshold for this trial;
substep 3: repeating the steps, recording the values of the vehicle speed, the whole vehicle mass, the liquid filling ratio, the roll angle, the lateral acceleration and the air bag pressure transverse transfer rate when the value H of the roll state in 150 tests reaches 0.9 for the first time, and recording the values as the values
Figure BDA0002505277430000043
Step four: fitting a functional relation between the rollover threshold and the influence factors thereof by using the SVR
Binding sample data
Figure BDA0002505277430000044
Respectively fitting functions f of the roll angle threshold value, the vehicle speed, the whole vehicle mass and the liquid filling ratio by using SVR τ (x) Function f of lateral acceleration threshold, vehicle speed, vehicle mass and charge ratio θ (x) Function f of lateral transfer rate threshold of air bag pressure, vehicle speed, vehicle mass, and fill ratio η (x);
Step five: tank car rollover threshold dynamic estimation based on fitted functional relation
When the tank car runs, the speed of the car is read through the CAN bus of the car body
Figure BDA0002505277430000045
In advance static measurement vehicle quality->
Figure BDA0002505277430000046
And filling ratio>
Figure BDA0002505277430000047
Get->
Figure BDA0002505277430000048
Respectively count->
Figure BDA0002505277430000049
And &>
Figure BDA00025052774300000410
Figure BDA00025052774300000411
Controlling a threshold for a roll angle>
Figure BDA00025052774300000412
Controlling a threshold for lateral acceleration>
Figure BDA00025052774300000413
Controlling a threshold value for the lateral transfer rate of the air bag pressure; />
Figure BDA00025052774300000414
A pre-warning threshold value for the roll angle,
Figure BDA00025052774300000415
early warning threshold for lateral acceleration>
Figure BDA00025052774300000416
For transverse transfer rate of air bag pressureAnd (5) early warning threshold values.
Compared with the prior art, the invention has the following advantages and beneficial effects:
1. the invention provides a rollover characterization parameter of the lateral transfer rate of the air bag pressure, meets the requirement of redundant judgment of rollover danger, and improves the reliability of rollover prevention and control;
2. the rollover threshold value calibration and calibration device can accurately acquire data of various characterization parameters of the tank car when rollover occurs in real time, and can be applied to real-vehicle tests;
3. the rollover scene library summarized by the invention covers typical scenes of rollover when the tank truck actually runs;
4. according to the invention, the functional relation between the rollover threshold and the influence factors thereof is fitted through real vehicle test data and the SVR, so that the dynamic estimation of the rollover threshold is realized.
Drawings
FIG. 1 is a general design scheme diagram of tank car rollover threshold value calibration method and device
FIG. 2 is a structural diagram of a tank car rollover threshold value calibration device
FIG. 3 is a left-hand steering test trace diagram of a tank truck J with a radius of 45.7m
FIG. 4 is a track diagram of a double-line-shifting test of a tank car
Detailed Description
The technical solutions provided by the present invention will be described in detail below with reference to specific examples, and it should be understood that the following detailed description is only illustrative and not intended to limit the scope of the present invention.
The invention provides a highly reliable dynamic estimation method for a tank car rollover threshold value, which comprises the steps of firstly determining rollover characterization parameters and factors influencing the rollover threshold value, building a rollover threshold value calibration device, then carrying out tank car rollover threshold value calibration tests under typical rollover scenes in a closed test field, then processing data and dynamically calibrating rollover threshold values under different typical rollover scenes, further fitting a functional relation between the rollover threshold value and the influencing factors by utilizing SVR (singular value representation) and finally realizing dynamic estimation of the tank car rollover threshold value based on the fitted functional relation. The invention provides a rollover characterization parameter of the lateral transfer rate of the air bag pressure for a tank car using an air bag separated air suspension, and meets the requirement of redundant judgment of rollover dangers; the tank car rollover threshold value calibration device is built by utilizing the high-precision inertia measurement unit, the pressure sensor, the wheel force sensor and the rollover prevention frame, and can be applied to a real-vehicle test; summarizing a typical rollover scene library suitable for the tank car by referring to a plurality of vehicle stability test standards in combination with an actual rollover scene of the tank car; and fitting a functional relation between the rollover threshold and the influence factors thereof through real vehicle test data and the SVR to realize dynamic estimation of the rollover threshold. The general design scheme of the invention is shown in figure 1, and the specific steps comprise:
the method comprises the following steps: side turning characteristic parameters and factors influencing a side turning threshold are determined and a side turning threshold calibration device is built
The roll angle, the lateral acceleration and the transverse load transfer rate are common rollover characterizing parameters and can visually reflect the roll stability of the vehicle. However, the load measurement of the wheels is difficult in a high-speed operation state, and for the tank truck using the air bag separated air suspension, because the corresponding relation exists between the air bag pressure at the wheels and the load of the wheels and the air bag distribution is symmetrical left and right, the rollover characteristic parameter of the air bag pressure transverse transfer rate is provided, so the rollover characteristic parameter is selected as the roll angle tau, the lateral acceleration theta and the air bag pressure transverse transfer rate eta. The η calculation formula is:
Figure BDA0002505277430000061
in the formula (1), F ls Is the left air bag pressure of the s th axle of the tank car, F rs The pressure of an air bag at the right side of the s th axle of the tank truck, s is the number of the axles, and s =1,2, …, e and e are the total number of the axles of the tank truck.
When the curvature radius of the road is fixed, the larger the vehicle speed and the whole vehicle mass are, the larger the centrifugal force of the tank car is, and when the moment of the self weight of the vehicle on the wheels is not enough to overcome the centrifugal force, the vehicle can turn over. Under the non-full load state of the tank car, because of the continuous change of the motion state of the tank car and the liquidity of liquid, the liquid in the tank body is easy to shake, and additional force and moment can be generated on the side wall of the tank body, so that the side-tipping stability of the tank car is reduced, and the side tipping of the vehicle is induced. Therefore, the factors influencing the rollover threshold value of the tank car are selected as the vehicle speed v, the mass m of the whole vehicle and the liquid filling ratio lambda.
The side-turning threshold calibration device comprises a high-precision inertia measurement unit, a plurality of pressure sensors and two wheel force sensors (the introduction and the function of the wheel force sensors are shown in a reference document- -Yanhuawen, a Bluetooth-based wheel force data transmission system design [ D ]]Zhenjiang, science and technology university of Jiangsu, 2013) and two anti-rollover frames. The high-precision inertia measurement unit is installed at a position close to the center of mass of the tank car, the pressure sensors are installed at the vent valves of all air bags of the air suspension of the tank car, the wheel force sensors are installed on wheels on two sides of the last shaft of the tail of the tank car, and the side-turning prevention frames are installed on two sides of the tank car as shown in figure 2 (a two-shaft tank car is arranged in the figure, and the number of the pressure sensors needs to be increased for the three-shaft tank car). The high-precision inertial measurement unit acquires a roll angle tau and a lateral acceleration theta, and the wheel force sensor acquires a vertical force G of a left wheel of a last axle l And the vertical force G of the right wheel of the final axle r . As more and more tank cars are equipped with an electronic system such as an anti-lock braking system (ABS), etc., wheel speed sensors have been installed in vehicles, and an average value of information of wheel speed sensors of two wheels (i.e., non-steered wheels) of a last axle is collected as a vehicle speed v through a vehicle body CAN bus. The mass m and the liquid filling ratio lambda of the whole vehicle are obtained by static measurement in advance, the data output frequency of each sensor is the same, and the collected data are ensured to correspond one to one.
Step two: tank car rollover threshold calibration test under typical rollover scene carried out in closed test field
After determining the rollover characterization parameters, the factors influencing the rollover threshold value and the calibration device, designing a tank car typical rollover scene library, and developing a rollover threshold value calibration test in a closed test field.
The tank truck rollover scene library needs to consider three scene elements of driving behavior, liquid filling ratio and longitudinal gradient (downhill), and each scene element is divided as shown in the following table. Selecting one quantitative parameter from the driving behavior element, the liquid filling ratio element and the longitudinal gradient element, and carrying out permutation and combination to obtain different rollover scenes. To distinguish from sideslip, the low adhesion coefficient is not considered for the moment.
Figure BDA0002505277430000071
The J-steering test trajectory setting refers to steering test regulations in GB/T6323-2014 automobile steering stability test method, as shown in FIG. 3. The double-lane-shifting test trajectory is set according to the requirements specified in ISO 3888-2, part 2, namely obstacle avoidance, of a passenger car, a test lane for lane abrupt change control, and is shown in figure 4. When the scene elements are combined in an arrangement mode, in consideration of test safety, the J-turn test is not supported by the longitudinal steep slope of <7%, so that 4 (J-turn) × 5 (liquid filling ratio) × 1 (longitudinal slope < 3%) +1 (double shift line) × 5 (liquid filling ratio) × 2 (longitudinal slope) =30 rollover scenes exist.
Through the real vehicle test, the numerical changes of rollover representation parameters and factors influencing the rollover threshold value of the tank car in the process from safe driving to rollover occurrence under different rollover scenes are recorded. The method comprises the following specific steps:
substep 1: the calibration test is carried out on a dry and solid road surface, and the peak value adhesion coefficient of the road surface is not less than 0.9; the reliability of each sensor in the calibration device, the safety of the anti-rollover frame and the potential safety hazard of a test site need to be checked;
substep 2: sequentially setting driving behaviors, liquid filling ratios and longitudinal gradients in a closed test field based on a determined rollover scene, drawing test tracks of J steering and double shifting lines on the test field by using striking colors, and statically measuring the mass m and the liquid filling ratio lambda of the whole vehicle before the test starts;
substep 3: referring to the speed setting in a J steering test of GB/T38185-2019 electronic stability control system performance requirements and test method for commercial vehicles, a driver keeps constant vehicle speed as much as possible and runs according to a track, the driver gradually increases 2km/h with 32km/h as an initial speed until the vertical force of the tire on the last shaft side is 0 or the side of the rollover prevention support lands in the continuous 5-time test process to finish the rollover threshold calibration test in the current scene, and the 5-time test roll angle tau, the lateral acceleration theta, the lateral transfer rate eta of the air bag pressure, the vehicle speed v, the whole vehicle mass m and the liquid filling ratio are storedLambda, vertical force G of left wheel of last axle l Last right wheel vertical force G r The data of (a);
and substep 4: repeating the substep 2 and the substep 3, completing threshold value calibration tests under 30 rollover scenes and storing data;
step three: processing data and dynamically calibrating rollover thresholds in different typical rollover scenarios
After 30 rollover scene calibration tests are completed, 5 times of test data are stored in each scene, and 150 times of test data are stored in total. In order to further improve the accuracy and reliability of data, the lateral inclination angle tau, the lateral acceleration theta, the air bag pressure transverse transfer rate eta, the vehicle speed v and the vertical force G of the left wheel of the final axle which are acquired by each test are filtered by adopting the weighted mean value which is practical in engineering l Last right wheel vertical force G r The data of (2) is processed (the mass m and the liquid filling ratio lambda of the whole vehicle in a single test are constant values, and the data do not need to be processed). Take lateral acceleration as an example, θ t For a group of data of lateral acceleration in a certain test, t =1,2, …, c, c is the data quantity of the lateral acceleration in the test, and the weighted mean filtering processing method is as follows:
when t =1 and t = c,
Figure BDA0002505277430000081
when t =2 and t = c-1,
Figure BDA0002505277430000082
when t is more than or equal to 3 and less than or equal to c-2,
Figure BDA0002505277430000083
the lateral dip angle tau, the air bag pressure transverse transfer rate eta, the vehicle speed v and the vertical force G of the left wheel of the final axle of the test l Last right wheel vertical force G r The data is filtered in the same way.
After the data of each item of 150 tests are processed by the method, the roll state H is calculated, and the formula is as follows:
Figure BDA0002505277430000084
in the formula (2), the reaction mixture is,
Figure BDA0002505277430000085
is the vertical force of the left wheel of the last axle subjected to weighted mean filtering processing>
Figure BDA0002505277430000086
The vertical force of the right wheel of the final axle after the weighted mean filtering processing. The method is characterized in that a rollover threshold value is calibrated by a tank car roll state H, and the method specifically comprises the following steps:
substep 1: uniformly displaying the data of the roll angle, the lateral acceleration, the transverse transfer rate of the air bag pressure, the vehicle speed and the roll state of a certain test on a time axis, namely the curves of all the data have the same starting time and ending time; the whole vehicle mass and the liquid filling ratio in the test are constant values;
substep 2: searching a point at which the value H of the side-tipping state reaches 0.9 for the first time (the value can be changed to be 0.9 according to different requirements of the side-tipping prevention and control degree) from the initial moment, and recording values of the vehicle speed, the whole vehicle mass, the liquid filling ratio, the side-tipping angle, the lateral acceleration and the air bag pressure transverse transfer rate at the moment, and recording the values as
Figure BDA0002505277430000091
Wherein->
Figure BDA0002505277430000092
Is the rollover threshold for this trial;
substep 3: repeating the steps, recording the values of the vehicle speed, the whole vehicle mass, the liquid filling ratio, the roll angle, the lateral acceleration and the air bag pressure transverse transfer rate when the value H of the roll state in 150 tests reaches 0.9 for the first time, and recording the values as the values
Figure BDA0002505277430000093
Step four: fitting a functional relation between the rollover threshold and the influence factors thereof by using the SVR
The Support Vector machine is developed for general estimation and prediction problems, and can be used to perform function Regression fitting, namely SVR (Support Vector Regression), in addition to classification using the Support Vector machine. SVR has the advantages of low computational complexity and good generalization performance, by minimizing the prediction error, finding a function that can well approximate the training examples, and maximizing the flatness of the function when the error is minimized reduces the risk of fitting.
Respectively fitting functions f of the roll angle threshold value, the vehicle speed, the whole vehicle mass and the liquid filling ratio by using SVR τ (x) Function f of lateral acceleration threshold, vehicle speed, vehicle mass and charge ratio θ (x) Function f of lateral transfer rate threshold of air bag pressure, vehicle speed, vehicle mass, and fill ratio η (x) In f with τ (x) An example is the SVR fitting function method.
For the training set (x) i ,y i ),
Figure BDA0002505277430000094
The expression pattern of SVR is:
Figure BDA0002505277430000095
in equation (3), w is an adjustable weight vector;
Figure BDA0002505277430000096
representing a non-linear mapping, mapping the input quantities to a higher dimensional feature space; b represents a bias; the superscript T denotes transposing the matrix.
Introducing a relaxation variable delta under the condition of controlling the fitting accuracy epsilon i And
Figure BDA0002505277430000097
f τ (x) The objective function solved by the expression is:
Figure BDA0002505277430000101
in the formula (4), C is a regularization constant. The Lagrange multiplier mu is introduced to be more than or equal to 0,
Figure BDA0002505277430000102
α≥0,/>
Figure BDA0002505277430000103
obtained by the Lagrange multiplier method:
Figure BDA0002505277430000104
order to
Figure BDA0002505277430000105
For w, b, delta i And &>
Figure BDA0002505277430000106
Has a partial derivative of zero:
Figure BDA0002505277430000107
bringing formula (6) into formula (5) yields the dual problem of SVR:
Figure BDA0002505277430000108
obtained by formula (7)
Figure BDA0002505277430000109
According to>
Figure BDA00025052774300001010
To obtain w * Finally, find f τ (x) Comprises the following steps: />
Figure BDA00025052774300001011
Specific methods of using SVR and methods of calculating b can be found in the literature (Zhou Zhihua. Machine learning [ M)]Beijing, qinghua university Press 2016, 133-137). In the same manner, f is obtained θ (x) And f η (x)。
Step five: tank car rollover threshold dynamic estimation based on fitted functional relation
When the tank car runs, the speed of the car is read through the CAN bus of the car body
Figure BDA0002505277430000111
The mass of the whole vehicle is statically measured in advance>
Figure BDA0002505277430000112
And the filling ratio->
Figure BDA0002505277430000113
Get>
Figure BDA0002505277430000114
Respectively count>
Figure BDA0002505277430000115
And &>
Figure BDA0002505277430000116
The rollover prevention and control part comprises a pre-warning part and a control part, wherein the rollover pre-warning part reminds a driver to drive safely when the vehicle has smaller rollover danger, and the rollover control part executes operation to prevent rollover when the vehicle has larger rollover danger. Because the rollover early warning and rollover control are applied to rollover scenes with different risk degrees, the rollover threshold value is divided into an early warning threshold value and a control threshold value. Thus, it is possible to provide
Figure BDA0002505277430000117
Controlling a threshold for a roll angle>
Figure BDA0002505277430000118
Controlling a threshold for lateral acceleration>
Figure BDA0002505277430000119
Controlling a threshold value for the lateral transfer rate of the air bag pressure; />
Figure BDA00025052774300001110
For a roll angle warning threshold value>
Figure BDA00025052774300001111
Early warning threshold for lateral acceleration>
Figure BDA00025052774300001112
And (4) early warning threshold value for the transverse transfer rate of the air bag pressure. />

Claims (1)

1. A highly reliable dynamic estimation method for a tank car rollover threshold value is characterized by comprising the following specific steps:
the method comprises the following steps: side turning characteristic parameters and factors influencing a side turning threshold are determined and a side turning threshold calibration device is built
The rollover characterizing parameters are selected as a side inclination angle tau, a lateral acceleration theta and an air bag pressure transverse transfer rate eta, factors influencing the rollover threshold value of the tank car are selected as a vehicle speed v, a whole vehicle mass m and a liquid filling ratio lambda, and the eta calculation formula is as follows:
Figure FDA0004053975100000011
in the formula (1), F ls Is the pressure of the left air bag of the s-th axle of the tank car, F rs The pressure of an air bag at the right side of the s th axle of the tank car, s is the number of the axles, s =1,2, …, e, e is the total number of the axles of the tank car;
the rollover threshold value calibration device comprises a high-precision inertia measurement unit, a plurality of pressure sensors, two wheel force sensors and two rollover prevention frames, wherein the high-precision inertia measurement unit is arranged close to the center of mass of the tank car; height ofThe precision inertia measurement unit acquires a roll angle tau and a lateral acceleration theta, and the wheel force sensor acquires a vertical force G of a left wheel of a last shaft l And right wheel vertical force G r Acquiring the average value of information of two wheel speed sensors of a last shaft as a vehicle speed v through a vehicle body CAN bus, wherein the data output frequencies of the sensors are the same, and the mass m and the liquid filling ratio lambda of the whole vehicle are obtained by static measurement in advance;
step two: tank car rollover threshold calibration test under typical rollover scene carried out in closed test field
The division of each scene element of the tank car rollover scene library is shown as the following table:
Figure FDA0004053975100000012
30 rollover scenes are formed after the scene elements are arranged and combined; the tank car rollover threshold calibration test under a typical rollover scene specifically comprises the following steps:
substep 1: the calibration test is carried out on a dry and solid road surface, and the peak value adhesion coefficient of the road surface is not less than 0.9; checking the reliability of each sensor in the calibration device, the safety of the anti-rollover frame and whether potential safety hazards exist in a checking test field;
substep 2: sequentially setting driving behaviors, liquid filling ratios and longitudinal gradients in a closed test field based on the determined rollover scene, drawing test tracks of J steering and double shifting lines on the test field, and statically measuring the mass m and the liquid filling ratio lambda of the whole vehicle before the test is started;
substep 3: keeping constant vehicle speed and running according to a track, gradually increasing by 2km/h by taking 32km/h as an initial speed until the tire vertical force on the side of the final shaft is 0 or the side of the rollover prevention support lands in the continuous 5-time test process to finish the rollover threshold calibration test in the current scene, and storing the 5-time test roll angle tau, the lateral acceleration theta, the air bag pressure lateral transfer rate eta, the vehicle speed v, the whole vehicle mass m, the liquid filling ratio lambda and the vertical force G of the left wheel of the final shaft l Vertical force G of right wheel of final axle r The data of (a);
substep 4: repeating the substep 2 and the substep 3, completing threshold value calibration tests under 30 rollover scenes and storing data;
step three: processing data and dynamically calibrating rollover thresholds for different typical rollover scenarios
After 30 rollover scene calibration tests are completed, 5 times of test data are stored in each scene, and 150 times of test data are stored in total; adopting weighted mean filtering to collect the roll angle tau, the lateral acceleration theta, the air bag pressure transverse transfer rate eta, the vehicle speed v and the vertical force G of the left wheel of the final axle in each test l Last right wheel vertical force G r Processing the data; take lateral acceleration as an example, θ t For a group of data of the lateral acceleration in a certain test, t =1,2, …, c, c is the data quantity of the lateral acceleration in the test, and the weighted mean filtering processing method is as follows:
when t =1 and t = c,
Figure FDA0004053975100000021
when t =2 and t = c-1,
Figure FDA0004053975100000022
when t is more than or equal to 3 and less than or equal to c-2,
Figure FDA0004053975100000023
the lateral inclination angle tau, the air bag pressure lateral transfer rate eta, the vehicle speed v and the vertical force G of the left wheel of the final axle of the test l Vertical force G of right wheel of final axle r Filtering the data by the same method;
after the data of each test of 150 times are processed by the method, the roll state H is calculated, and the formula is as follows:
Figure FDA0004053975100000031
in the formula (2), the reaction mixture is,
Figure FDA00040539751000000312
is the vertical force of the left wheel of the last axle subjected to weighted mean filtering processing>
Figure FDA00040539751000000313
The method comprises the following steps of calibrating a rollover threshold value for the vertical force of the right wheel of the last axle after weighted mean filtering treatment by using the side-tipping state H of the tank car, and specifically comprises the following steps:
substep 1: uniformly displaying the data of the roll angle, the lateral acceleration, the transverse transfer rate of the air bag pressure, the vehicle speed and the roll state of a certain test on a time axis, namely the curves of all data have the same starting time and ending time; the whole vehicle mass and the liquid filling ratio in the test are constant values;
and substep 2: searching a point at which the value H of the side-rolling state reaches 0.9 for the first time from the initial moment, recording the values of the vehicle speed, the whole vehicle mass, the liquid filling ratio, the side-rolling angle, the lateral acceleration and the air bag pressure transverse transfer rate at the moment, and recording the values as
Figure FDA0004053975100000032
Wherein->
Figure FDA0004053975100000033
The rollover threshold for this trial;
substep 3: repeating the substep 1 and the substep 2, recording the values of the vehicle speed, the vehicle mass, the liquid filling ratio, the roll angle, the lateral acceleration and the air bag pressure transverse transfer rate when the roll state H value reaches 0.9 for the first time in 150 tests, and recording the values as the values
Figure FDA0004053975100000034
Step four: fitting a functional relation between the rollover threshold and the influencing factors thereof by using the SVR
Binding sample data
Figure FDA0004053975100000035
Respectively fitting the roll angle threshold value with the vehicle speed and the whole vehicle mass by using SVRFunction f of quantity and filling ratio τ (x) Function f of lateral acceleration threshold, vehicle speed, vehicle mass, and fill-liquid ratio θ (x) Function f of lateral transfer rate threshold of air bag pressure, vehicle speed, vehicle mass, and fill ratio η (x);
Step five: tank truck rollover threshold dynamic estimation based on fitted functional relationship
When the tank car runs, the speed of the car is read through the CAN bus of the car body
Figure FDA0004053975100000036
In advance static measurement vehicle quality->
Figure FDA0004053975100000037
And filling ratio>
Figure FDA0004053975100000038
To obtain
Figure FDA0004053975100000039
Respectively count>
Figure FDA00040539751000000310
And &>
Figure FDA00040539751000000311
Figure FDA00040539751000000314
Controlling a threshold for a roll angle>
Figure FDA0004053975100000041
Controlling a threshold for lateral acceleration>
Figure FDA0004053975100000042
Controlling a threshold value for the lateral transfer rate of the air bag pressure; />
Figure FDA0004053975100000043
For a roll angle warning threshold value>
Figure FDA0004053975100000044
Early warning threshold for lateral acceleration>
Figure FDA0004053975100000045
And (4) early warning threshold value for the transverse transfer rate of the air bag pressure. />
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