A method for constructing test scenarios for an early warning system

Abstract

This invention discloses a method for constructing a test scenario for an early warning system. The method establishes a database of static element information within the test scenario. Based on the test vehicle's basic attribute information, static element information, and information on different types of risky road sections, the critical safe speed of the test vehicle on the risky road sections in the test scenario is obtained through driving stability simulation analysis. A three-level braking deceleration standard is set. The position of the three-level standard early warning signal section is obtained through the acquired dynamic element information, the critical safe speed of the test vehicle on the risky road sections in the test scenario, and the three-level braking deceleration standard in the test scenario, thus constructing the test scenario for the early warning system. The constructed test scenario for the early warning system can be used to test both pre-danger and near-danger early warning systems for vehicles.

Description

Technical Field

[0001] This invention relates to the field of test scenario construction methods, and more particularly to a test scenario construction method for an early warning system. Background Technology

[0002] In modern production and daily life, assisted driving and autonomous driving have gradually become integrated into our lives. Warning systems that alert drivers to abnormal road conditions are particularly important during autonomous driving. Current testing scenarios for warning systems primarily test traditional Automatic Emergency Braking (AEB) systems. However, AEB systems work by detecting obstacles or dangerous road sections using radar. The distance at which an AEB system identifies and warns of obstacles or dangerous road sections is 40-60 meters, which constitutes a near-hazard warning. Because the distance is too short, drivers have limited time, especially for tanker trucks, where the probability of danger is high. Therefore, we are now developing warning systems that extend beyond the location of the dangerous road section, providing near-hazard warnings (distance greater than 280-320 meters). Thus, we need to construct a testing scenario for warning systems that can test both near-hazard warning systems and near-hazard warning systems.

[0003] Therefore, the question is how to invent a test scenario construction method for an early warning system, so that the constructed test scenario can be used to test both pre-danger and near-danger early warning systems. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for constructing test scenarios for an early warning system, enabling the constructed test scenarios to test both pre-danger and near-danger early warning systems.

[0005] This invention provides a method for constructing test scenarios for an early warning system, and establishes a database of static element information in the test scenarios;

[0006] Establish a database of information on different types of risky road sections in the test scenario;

[0007] Establish a database of basic attribute information for test vehicles;

[0008] Establish a simulation model for the driving stability of the test vehicle;

[0009] Acquire dynamic element information; the dynamic element information includes the motion state information and position information of the test vehicle in the actual test scenario, as well as the meteorological information in the vehicle's driving environment;

[0010] Based on the basic attribute information, static element information, and different types of risky road section information of the test vehicle, the critical safe speed of the test vehicle in the risky road section of the test scenario is obtained through driving stability simulation analysis.

[0011] Establish a three-stage braking deceleration standard;

[0012] By acquiring dynamic element information, the critical safe speed of the test vehicle on the risky road section in the test scenario, and the three-level braking deceleration standard in the test scenario, the position of the three-level standard warning signal section is obtained, and the test scenario of the warning system is constructed.

[0013] When the test vehicle is tested in the warning system test scenario, the location of the braking warning issued by the test vehicle and the instantaneous speed of the test vehicle at the moment of braking warning are obtained; the effectiveness of the warning system of the test vehicle is evaluated by comparing the location of the braking warning issued by the test vehicle with the cross-sectional location of the Level 3 standard warning signal.

[0014] Compared with the prior art, the present invention has the following beneficial effects: by obtaining the critical safe speed of the test vehicle on the risky road section in the test scenario through driving stability simulation analysis based on the basic attribute information, static element information, and different types of risky road section information of the test vehicle, the test scenario of the constructed early warning system can obtain the critical safe speed of the nearest dangerous road section at any time during the test vehicle's test journey.

[0015] By setting a three-level braking deceleration standard and combining it with the speed of the test vehicle at the warning time, the cross-sectional position of the three-level standard warning signal corresponding to the warning position of the test vehicle is obtained, thereby enabling the evaluation of the effectiveness of the warning position of the test vehicle; therefore, the effectiveness of the warning position can be evaluated regardless of whether the distance between the location of the test vehicle at the warning time and the nearest risk section is 40-60m or 280-320m.

[0016] Therefore, the test scenario for the constructed early warning system can be used to test both the imminent danger early warning system and the near danger early warning system.

[0017] Furthermore, the static element information includes road network information, road surface information, and static environment information;

[0018] The road network information includes urban roads, expressways, and mountain roads; the risk road section type information includes sharp bends and steep slopes, sections near water or cliffs, tunnel sections, road surface collapse sections, and bridge sections affected by crosswinds; the road surface information includes dry asphalt pavement, wet and slippery pavement, and icy and snowy pavement.

[0019] Static environmental information includes obstacles, surrounding landscape, and traffic facilities.

[0020] Furthermore, the basic attribute information of the test vehicle includes vehicle weight, geometric dimensions, and performance information;

[0021] The motion status information of the test vehicle includes vehicle speed and vehicle acceleration;

[0022] The meteorological information of the vehicle's driving environment includes weather temperature, rain, snow, and wind level.

[0023] Furthermore, the basic attribute information of the test vehicle also includes the shape of the tank and the liquid filling ratio of the cargo inside the tank.

[0024] The advantage of adopting the previous step is that the test scenario of the constructed early warning system can effectively test the tank truck early warning system;

[0025] When testing the tank truck early warning system, the position of the three-level standard early warning signal section of the tank truck is obtained by combining the speed of the tank truck at the time of the early warning with the information on the liquid filling ratio of the cargo inside the tank. This allows the test scenario of the constructed early warning system to test both the near-term and near-term warning systems of the tank truck.

[0026] Furthermore, the method for obtaining the critical safe speed of the risky road section includes the following steps: when the risky road section is a prohibited road section or a road section with a clearly defined speed limit, the critical safe speed is 0 or the road section speed limit.

[0027] When the risky road section is a section without a clear speed limit, the critical safe speed is the lowest of the two critical speeds for the test vehicle to avoid skidding and rollover.

[0028] Furthermore, when the risky road section is a section with no clear speed limit, the critical speed for skidding and the critical speed for rollover of the test vehicle in the risky road section are obtained based on road network information, risky road section type information, road surface information, basic attribute information of the test vehicle, and motion state information of the test vehicle.

[0029] The method for obtaining the critical speed for sideslip includes: inputting the basic attribute information of the test vehicle into the driving stability simulation; setting the test vehicle to drive at a constant speed on a road section with no clear speed limit; setting multiple driving speeds for the test vehicle; obtaining the vehicle's driving trajectory under different driving speed conditions; and the lateral position of the vehicle's front axle center in the Frenet coordinate system with the vehicle's center of mass as the origin. Lateral position of the rear axle center of the vehicle ;

[0030] Throughout the entire high-risk section, [the following occurred] , The minimum speed corresponding to a value range of 0.2-0.3 is the critical speed for sideslip of the test vehicle on the risky road section;

[0031] Methods for obtaining the critical rollover speed include:

[0032] Obtain the rollover risk index and from the starting point of the risky road section Point to the end of the risky road section The probability of rollover on the entire high-risk road section. ;

[0033] Throughout the entire high-risk section, [the following occurred] , The value range is 0.7-0.9, and , When the value ranges from 0.8 to 0.9, the corresponding minimum speed is the critical speed for the test vehicle to roll over on the risky road section.

[0034] Furthermore, , The methods for obtaining it include:

[0035] ; Indicates the length of the road segment. ;

[0036] ;

[0037] Indicates the safe rollover speed at a given time. The probability of a vehicle rolling over; This is the maximum set value for the lateral load transfer rate of the axle; exceeding this value is considered an indication that the vehicle has rolled over. The value ranges from 0.8 to 0.9;

[0038] , The lateral load transfer rate of the axle; the lateral load transfer rate of the axle The driving stability of the test vehicle is obtained through simulation based on the basic attribute information of the test vehicle.

[0039] The advantage of the previous step is that it allows us to determine the critical safe speed for vehicles on different dangerous road sections.

[0040] Preferably, the driving stability simulation is established using Simulink and TruckSim simulations; specifically, it includes: building an elliptic pendulum model in Simulink to describe the lateral impact of the liquid in a non-inertial coordinate system:

[0041] ;{S}_{1}=\frac {{d}^{2}\theta} {d{t}^{2}}\left [ {{a}^{2}_{p}\left ( {\sin {\theta}} \right )^{2}+{b}^{2}_{p}\left ( {\cos {\theta}} \right )^{2}} \right ]+\frac {1} {2}\left ( {\frac {d\theta} {dt}} \right )^{2}\left ( {{a}^{2}_{p}-{b}^{2}_{p}} \right )\sin {2\theta}-g{b}_{p}\cos {\theta} ;{S}_{2}=2\eta \frac {d\theta} {dt}\left [ {{a}^{2}_{p}\left ( {\sin {\theta}} \right )^{2}+{b}^{2}_{p}\left ( {\cos {\theta}} \right )^{2}} \right ]-{V}_{x}\left ( {\frac {d\beta} {dt}+r} \right )^{2}{a}_{p}\sin {\theta}-\frac {dr} {dt}{e}_{2}{a}_{p}\sin {\theta} ;

[0042] ; ;

[0043] in The pendulum's swing angle; Let be the radius of the minor axis of the pendulum; Let be the radius of the major axis of the pendulum; is the dimensionless damping coefficient for lateral sloshing of the liquid; The vehicle's forward speed; The coordinates of the liquid's center of mass along the X-axis of the vehicle coordinate system; This is the distance from the center of the tank to the vehicle's tilt axis when the vehicle is stationary. The sideslip angle is the angle between the vehicle's center of gravity and its body. The vehicle's yaw rate; This refers to the vehicle body roll angle; It is the acceleration due to gravity;

[0044] The parameter calculation method for the elliptical pendulum model is as follows:

[0045] ; ;

[0046] ; ;

[0047] in, For the mass of the pendulum ball, For the mass of the stationary liquid, The total mass of the liquid in the tank. It is the ratio of the major and minor axes of the elliptical cross-section of the tank. The liquid filling ratio is the ratio of the liquid level to the height of the tank's cross-section. The radius of the minor axis of the tank's cross-section;

[0048] In TruckSim, set the parameters for the rigid body of the tanker truck, including the static liquid mass, vehicle mass, tire parameters, and suspension parameters. In the TruckSim environment, set the driving environment based on the road environment characteristics of the risk points. At risk points with sharp bends and steep slopes, it is necessary to set the road curvature, superelevation, longitudinal slope, road surface adhesion coefficient, circular curve length, and transition curve length; the road curvature is set to 130m, 150m, 200m, and 300m respectively; the road superelevation is set to 2%; the longitudinal slope is set to -4%; and the road surface adhesion coefficient is set to 0.3, 0.5, and 0.85 respectively. For road sections near water or cliffs, or those affected by strong winds, it is necessary to set the road curvature, superelevation, road surface adhesion coefficient, circular curve length, and transition curve length; set the crosswind speed, based on a level 7 wind speed. Use a driver model based on non-singular terminal sliding mode control to realize the vehicle's movement along the preset road. The driver model is as follows:

[0049] ; ;{W}_{S2}={x}_{m}\left [ {\left ( {{l}_{f}{k}_{1}-{l}_{r}{k}_{2}} \right ){I}^{-1}_{z}{V}^{-1}_{x}\frac {de} {dt}-\left ( {{l}_{r}{k}_{1}-{l}_{r}{k}_{2}} \right ){I}^{-1}_{z}\Delta \Psi +\left ( {{l}^{2}_{r}{k}_{1}+{l}^{2}_{r}{k}_{2}} \right ){I}^{-1}_{z}{V}^{-1}_{x}\frac {d\Delta \Psi} {dt}} \right ] ;

[0050] ; ;{W}_{S4}={x}_{m}\left [ {\left ( {{l}^{2}_{f}{k}_{1}+{l}^{2}_{r}{k}_{2}} \right ){I}^{-1}_{z}\rho -\frac {d{V}_{x}} {dt}\rho -{V}_{x}\frac {d\rho} {dt}} \right ] ; ;{\delta}_{f}=u=\frac {1} {{\mathrm{w}}_{3}}\left [ {{\mathrm{w}}_{1}+{\mathrm{w}}_{2}+\frac {q\lambda} {p}\left | {\frac {d{e}_{m}} {dt}} \right |^{2-\frac {p} {q}}tanh\left ( {\frac {d{e}_{m}} {dt}} \right )+{\varepsilon}_{1}tanh\left ( {s} \right )+{\varepsilon}_{2}s} \right ] ;

[0051] in, , These are the generalized tire lateral stiffnesses for the front and rear wheels, respectively. , These are the distances from the vehicle's center of gravity to the front and rear axles, respectively. For the overall vehicle weight; Let yaw moment be the moment of inertia of the vehicle body; This is the steering angle of the front wheels; Pre-aiming distance for the driver; For path curvature; , For two positive constants in the design, as the number increases... At the same time reduce This can both improve the approach speed and reduce chattering; For lateral deviation in trajectory tracking; This is the heading deviation.

[0052] In Simulink, the lateral force and torque generated by the lateral impact of the liquid are transmitted to the vehicle model in TruckSim, with the point of application being the lowest point of the tank bottom. The vehicle's operating state parameters are also present in the TruckSim vehicle model parameters. , , Pass it to Simulink;

[0053] The lateral sloshing force generated by the liquid sloshing is: ;

[0054] Among them, the lateral absolute acceleration of the mass of the stationary liquid. Absolute lateral acceleration of the pendulum ball and the lateral acceleration experienced by the tank The calculation method is as follows:

[0055] ;{a}_{pend}={V}_{x}\left ( {\frac {d\beta} {dt}+r} \right )+\frac {dr} {dt}{e}_{2}-\frac {{d}^{2}\phi} {d{t}^{2}}H-{a}_{p}\frac {{d}^{2}\theta} {d{t}^{2}}\sin {\theta}-{a}_{p}\cos {\theta}\left [ {{r}^{2}+\left ( {\frac {d\phi} {dt}} \right )^{2}+\left ( {\frac {d\theta} {dt}} \right )^{2}} \right ] ; ;

[0056] in, is the height of the center of mass of the stationary liquid from the tilt axis; c is the height of the pendulum ball from the tilt axis. The height of the tanker truck's sprung center of mass from the tilt axis; ;

[0057] The lateral tilting torque generated by the liquid sloshing about the center of the tank bottom The torque generated by the pendulum ball around the lowest point of the tank The torque generated by the mass of the stationary liquid around the lowest point of the tank composition:

[0058] ; and The expression is as follows:

[0059] ;{M}_{p}={-m}_{p}\left \{{{a}_{p}\cos {\theta}\left [ {{b}_{p}\left ( {{\frac {d\theta} {dt}}^{2}\sin {\theta}-\frac {{d}^{2}\theta} {d{t}^{2}}\cos {\theta}} \right )+\mathrm{g}} \right ]-{a}_{pend}\left ( {b-{b}_{p}\sin {\theta}} \right )} \right \} .

[0060] Furthermore, the method for obtaining the location of the level 3 standard early warning signal section in the test scenario includes the following steps:

[0061] The test scenario includes three standard warning signal section locations: standard easing braking warning signal section location, standard emergency braking warning signal section location, and standard full braking warning signal section location.

[0062] Three levels of braking deceleration standards are preset in the test scenario;

[0063] The three-level braking deceleration standards are: mild braking deceleration standard, emergency braking deceleration standard, and full braking deceleration standard;

[0064] By acquiring the motion state information of the test vehicle in the test scenario, the critical safe speed of the nearest risky road section ahead, and the three-level braking deceleration standard, the standard slow braking warning signal section position, the standard emergency braking warning signal section position, and the standard full braking warning signal section position are obtained according to Formula 1.

[0065] The deceleration standards for easing braking, emergency braking, and full braking are the 25th, 50th, and 75th percentiles of the distribution of the absolute value of deceleration when a commercial freight truck brakes at an initial speed of medium to high speed.

[0066] Furthermore, Formula 1 is as follows:

[0067] ;

[0068] ;

[0069] ;

[0070] The distance from the standard braking warning signal section to the starting point of the corresponding risky road section;

[0071] The distance from the standard emergency braking warning signal section location to the starting point of the corresponding risky road section;

[0072] The distance from the standard full braking warning signal section to the starting point of the corresponding risky road section;

[0073] The braking deceleration standard corresponding to slow braking. The standard for braking deceleration corresponding to emergency braking. The standard braking deceleration corresponding to full braking;

[0074] It is the maximum road surface adhesion coefficient that the road surface can provide for the vehicle to travel on. The value ranges from 0.2 to 0.85; It is the acceleration due to gravity; To obtain the instantaneous speed of the test vehicle, The critical safe speed for the risky road section; This represents the magnification factor of the braking distance of test vehicles with different liquid filling ratios in their tanks compared to the braking distance of non-liquid cargo vehicles under identical loading conditions; when the liquid filling ratio of the vehicle tank is 0.6~0.8, When the liquid filling ratio of the vehicle tank is less than 0.6 or greater than 0.8, .

[0075] The advantage of the previous step is that it enables the determination of the cross-sectional position of the three-level standard warning signal corresponding to the location where the test vehicle issues a warning, by pre-setting the three-level braking deceleration standard and the speed of the test vehicle at any location where a warning is issued during the test.

[0076] Furthermore, methods for evaluating the effectiveness of the test vehicle's warning system by comparing the location of the braking warning issued by the test vehicle with the cross-sectional location of the Level 3 standard warning signal include:

[0077] Obtain the distance from the location of the braking warning issued by the test vehicle to the starting point of the corresponding risky road segment. ; Calculate the timing of the braking warning issued by the test vehicle , , ;

[0078] when At that time, the effectiveness of the test vehicle's warning system was evaluated as excellent;

[0079] when At that time, the effectiveness of the warning system of the test vehicle was evaluated as good;

[0080] when At that time, the effectiveness of the test vehicle's warning system was evaluated and the result was deemed qualified;

[0081] when At that time, the effectiveness of the test vehicle's warning system was evaluated as unqualified;

[0082] To test the effective signal receiving distance of the vehicle warning system.

[0083] By utilizing the beneficial effects achieved in the previous step, the warning system of the test vehicle is effectively evaluated by identifying the warning location issued by the test vehicle and the corresponding Level 3 standard warning signal section location in the test scenario. Detailed Implementation

[0084] To better understand the technical solution of the present invention, the present invention will be further described below with reference to specific embodiments.

[0085] Example 1:

[0086] This embodiment provides a method for constructing a test scenario for an early warning system, which establishes a database of static element information in the test scenario.

[0087] Establish a database of information on different types of risky road sections in the test scenario;

[0088] Establish a database of basic attribute information for test vehicles; the basic attribute information for test vehicles includes vehicle weight, geometric dimensions, performance information, tank shape, and liquid filling ratio of the cargo inside the tank.

[0089] The motion status information of the test vehicle includes vehicle speed and vehicle acceleration;

[0090] The meteorological information of the vehicle's driving environment includes weather temperature, rain, snow, and wind level.

[0091] Establish a simulation model for the driving stability of the test vehicle;

[0092] Acquire dynamic element information; the dynamic element information includes the motion state information and position information of the test vehicle in the actual test scenario, as well as the meteorological information in the vehicle's driving environment;

[0093] Based on the basic attribute information, static element information, and different types of risky road section information of the test vehicle, the critical safe speed of the test vehicle in the risky road section of the test scenario is obtained through driving stability simulation analysis.

[0094] The static element information includes road network information, road surface information, and static environment information;

[0095] The road network information includes urban roads, expressways, and mountain roads; the risk road section type information includes sharp bends and steep slopes, sections near water or cliffs, tunnel sections, road surface collapse sections, and bridge sections affected by crosswinds; the road surface information includes dry asphalt pavement, wet and slippery pavement, and icy and snowy pavement.

[0096] Static environmental information includes obstacles, surrounding landscape, and traffic facilities;

[0097] The method for obtaining the critical safe speed of the risky road section includes the following steps: when the risky road section is a prohibited road section or a road section with a clearly defined speed limit, the critical safe speed is 0 or the road section speed limit.

[0098] When the risky road section is a road section with no clear speed limit, the critical safe speed is the lowest value between the critical speed for skidding that the test vehicle will not skid on and the critical speed for rollover that it will not roll over on the risky road section.

[0099] When the risky road section is a road section with no clear speed limit, the critical speed for skidding and the critical speed for rollover of the test vehicle in the risky road section are obtained based on road network information, risky road section type information, road surface information, basic attribute information of the test vehicle, and motion state information of the test vehicle.

[0100] The method for obtaining the critical speed for sideslip includes: inputting the basic attribute information of the test vehicle into the driving stability simulation; setting the test vehicle to drive at a constant speed on a road section with no clear speed limit; setting multiple driving speeds for the test vehicle; obtaining the vehicle's driving trajectory under different driving speed conditions; and the lateral position of the vehicle's front axle center in the Frenet coordinate system with the vehicle's center of mass as the origin. Lateral position of the rear axle center of the vehicle ;

[0101] Throughout the entire high-risk section, [the following occurred] , The minimum speed corresponding to a value range of 0.2-0.3 is the critical speed for sideslip of the test vehicle on the risky road section;

[0102] Methods for obtaining the critical rollover speed include:

[0103] Obtain the rollover risk index and from the starting point of the risky road section Point to the end of the risky road section The probability of rollover on the entire high-risk road section. ;

[0104] Throughout the entire high-risk section, [the following occurred] , The value range is 0.7-0.9, and , When the value ranges from 0.8 to 0.9, the corresponding minimum speed is the critical speed for the test vehicle to roll over on the risky road section.

[0105] , The methods for obtaining it include:

[0106] ; Indicates the length of the road segment. ;

[0107] ;

[0108] Indicates the safe rollover speed at a given time. The probability of a vehicle rolling over; This is the maximum set value for the lateral load transfer rate of the axle; exceeding this value is considered an indication that the vehicle has rolled over. The value ranges from 0.8 to 0.9;

[0109] , The lateral load transfer rate of the axle; the lateral load transfer rate of the axle The driving stability of the test vehicle is obtained through simulation based on the basic attribute information of the test vehicle.

[0110] Set three-level braking deceleration standards; preset three-level braking deceleration standards in the test scenario;

[0111] The three-level braking deceleration standards are the mild braking deceleration standard, the emergency braking deceleration standard, and the full braking deceleration standard; the mild braking deceleration standard, the emergency braking deceleration standard, and the full braking deceleration standard are the 25th percentile, 50th percentile, and 75th percentile of the distribution of the absolute value of deceleration when a commercial truck brakes at an initial speed of medium to high speed.

[0112] By acquiring dynamic element information, the critical safe speed of the test vehicle on the risky road section in the test scenario, and the three-level braking deceleration standard in the test scenario, the position of the three-level standard warning signal section is obtained, and the test scenario of the warning system is constructed.

[0113] The method for obtaining the location of the Level 3 standard early warning signal section in the test scenario includes the following steps:

[0114] The test scenario includes three standard warning signal section locations: standard easing braking warning signal section location, standard emergency braking warning signal section location, and standard full braking warning signal section location.

[0115] By acquiring the motion state information of the test vehicle in the test scenario, the critical safe speed of the nearest risky road section ahead, and the three-level braking deceleration standard, the standard slow braking warning signal section position, the standard emergency braking warning signal section position, and the standard full braking warning signal section position are obtained according to Formula 1.

[0116] Formula 1 is: ;

[0117] ;

[0118] ;

[0119] The distance from the standard braking warning signal section to the starting point of the corresponding risky road section;

[0120] The distance from the standard emergency braking warning signal section location to the starting point of the corresponding risky road section;

[0121] The distance from the standard full braking warning signal section to the starting point of the corresponding risky road section;

[0122] The braking deceleration standard corresponding to slow braking. The standard for braking deceleration corresponding to emergency braking. The standard braking deceleration corresponding to full braking;

[0123] It is the maximum road surface adhesion coefficient that the road surface can provide for the vehicle to travel on. The value ranges from 0.2 to 0.85; It is the acceleration due to gravity; To obtain the instantaneous speed of the test vehicle, The critical safe speed for the risky road section; This represents the magnification factor of the braking distance of test vehicles with different liquid filling ratios in their tanks compared to the braking distance of non-liquid cargo vehicles under identical loading conditions; when the liquid filling ratio of the vehicle tank is 0.6~0.8, When the liquid filling ratio of the vehicle tank is less than 0.6 or greater than 0.8, .

[0124] When the test vehicle is tested in the warning system test scenario, the location of the braking warning issued by the test vehicle and the instantaneous speed of the test vehicle at the moment of braking warning are obtained; the effectiveness of the warning system of the test vehicle is evaluated by comparing the location of the braking warning issued by the test vehicle with the cross-sectional location of the Level 3 standard warning signal.

[0125] The method for evaluating the effectiveness of the test vehicle's warning system by comparing the location of the braking warning issued by the test vehicle with the cross-sectional location of the Level 3 standard warning signal includes:

[0126] Obtain the distance from the location of the braking warning issued by the test vehicle to the starting point of the corresponding risky road segment. ; Calculate the timing of the braking warning issued by the test vehicle , , ;

[0127] when At that time, the effectiveness of the test vehicle's warning system was evaluated as excellent;

[0128] when At that time, the effectiveness of the warning system of the test vehicle was evaluated as good;

[0129] when At that time, the effectiveness of the test vehicle's warning system was evaluated and the result was deemed qualified;

[0130] when At that time, the effectiveness of the test vehicle's warning system was evaluated as unqualified;

[0131] To test the effective signal receiving distance of the vehicle warning system.

[0132] Example 2:

[0133] The content that is the same as in Example 1 will not be repeated here; the differences between this embodiment and Example 1 are as follows: This embodiment provides a method for constructing a test scenario for an early warning system, which also includes:

[0134] The driving stability simulation was established using Simulink and TruckSim simulations; specifically, it included building an elliptic pendulum model in Simulink to describe the lateral impact of the liquid in a non-inertial coordinate system.

[0135] ;{S}_{1}=\frac {{d}^{2}\theta} {d{t}^{2}}\left [ {{a}^{2}_{p}\left ( {\sin {\theta}} \right )^{2}+{b}^{2}_{p}\left ( {\cos {\theta}} \right )^{2}} \right ]+\frac {1} {2}\left ( {\frac {d\theta} {dt}} \right )^{2}\left ( {{a}^{2}_{p}-{b}^{2}_{p}} \right )\sin {2\theta}-g{b}_{p}\cos {\theta} ;{S}_{2}=2\eta \frac {d\theta} {dt}\left [ {{a}^{2}_{p}\left ( {\sin {\theta}} \right )^{2}+{b}^{2}_{p}\left ( {\cos {\theta}} \right )^{2}} \right ]-{V}_{x}\left ( {\frac {d\beta} {dt}+r} \right )^{2}{a}_{p}\sin {\theta}-\frac {dr} {dt}{e}_{2}{a}_{p}\sin {\theta} ;

[0136] ; ;

[0137] in The pendulum's swing angle; Let be the radius of the minor axis of the pendulum; Let be the radius of the major axis of the pendulum; is the dimensionless damping coefficient for lateral sloshing of the liquid; The vehicle's forward speed; The coordinates of the liquid's center of mass along the X-axis of the vehicle coordinate system; This is the distance from the center of the tank to the vehicle's tilt axis when the vehicle is stationary. The sideslip angle is the angle between the vehicle's center of gravity and its body. The vehicle's yaw rate; This refers to the vehicle body roll angle; It is the acceleration due to gravity;

[0138] The parameter calculation method for the elliptical pendulum model is as follows:

[0139] ; ;

[0140] ; ;

[0141] in, For the mass of the pendulum ball, For the mass of the stationary liquid, The total mass of the liquid in the tank. It is the ratio of the major and minor axes of the elliptical cross-section of the tank. The liquid filling ratio is the ratio of the liquid level to the height of the tank's cross-section. The radius of the minor axis of the tank's cross-section;

[0142] In TruckSim, set the parameters for the rigid body of the tanker truck, including the static liquid mass, vehicle mass, tire parameters, and suspension parameters. In the TruckSim environment, set the driving environment based on the road environment characteristics of the risk points. At risk points with sharp bends and steep slopes, it is necessary to set the road curvature, superelevation, longitudinal slope, road surface adhesion coefficient, circular curve length, and transition curve length; the road curvature is set to 130m, 150m, 200m, and 300m respectively; the road superelevation is set to 2%; the longitudinal slope is set to -4%; and the road surface adhesion coefficient is set to 0.3, 0.5, and 0.85 respectively. For road sections near water or cliffs, or those affected by strong winds, it is necessary to set the road curvature, superelevation, road surface adhesion coefficient, circular curve length, and transition curve length; set the crosswind speed, based on a level 7 wind speed. Use a driver model based on non-singular terminal sliding mode control to realize the vehicle's movement along the preset road. The driver model is as follows:

[0143] ; ;{W}_{S2}={x}_{m}\left [ {\left ( {{l}_{f}{k}_{1}-{l}_{r}{k}_{2}} \right ){I}^{-1}_{z}{V}^{-1}_{x}\frac {de} {dt}-\left ( {{l}_{r}{k}_{1}-{l}_{r}{k}_{2}} \right ){I}^{-1}_{z}\Delta \Psi +\left ( {{l}^{2}_{r}{k}_{1}+{l}^{2}_{r}{k}_{2}} \right ){I}^{-1}_{z}{V}^{-1}_{x}\frac {d\Delta \Psi} {dt}} \right ] ;

[0144] ; ;{W}_{S4}={x}_{m}\left [ {\left ( {{l}^{2}_{f}{k}_{1}+{l}^{2}_{r}{k}_{2}} \right ){I}^{-1}_{z}\rho -\frac {d{V}_{x}} {dt}\rho -{V}_{x}\frac {d\rho} {dt}} \right ] ; ;{\delta}_{f}=u=\frac {1} {{\mathrm{w}}_{3}}\left [ {{\mathrm{w}}_{1}+{\mathrm{w}}_{2}+\frac {q\lambda} {p}\left | {\frac {d{e}_{m}} {dt}} \right |^{2-\frac {p} {q}}tanh\left ( {\frac {d{e}_{m}} {dt}} \right )+{\varepsilon}_{1}tanh\left ( {s} \right )+{\varepsilon}_{2}s} \right ] ;

[0145] in, , These are the generalized tire lateral stiffnesses for the front and rear wheels, respectively. , These are the distances from the vehicle's center of gravity to the front and rear axles, respectively. For the overall vehicle weight; Let yaw moment be the moment of inertia of the vehicle body; This is the steering angle of the front wheels; Pre-aiming distance for the driver; For path curvature; , For two positive constants in the design, as the number increases... At the same time reduce This can both improve the approach speed and reduce chattering; For the lateral deviation in trajectory tracking; This is the heading deviation.

[0146] In Simulink, the lateral force and torque generated by the lateral impact of the liquid are transmitted to the vehicle model in TruckSim, with the point of application being the lowest point of the tank bottom. The vehicle's operating state parameters are also present in the TruckSim vehicle model parameters. , , Pass it to Simulink;

[0147] The lateral sloshing force generated by the liquid sloshing is: ;

[0148] Among them, the lateral absolute acceleration of the mass of the stationary liquid. Absolute lateral acceleration of the pendulum ball and the lateral acceleration experienced by the tank The calculation method is as follows:

[0149] ;{a}_{pend}={V}_{x}\left ( {\frac {d\beta} {dt}+r} \right )+\frac {dr} {dt}{e}_{2}-\frac {{d}^{2}\phi} {d{t}^{2}}H-{a}_{p}\frac {{d}^{2}\theta} {d{t}^{2}}\sin {\theta}-{a}_{p}\cos {\theta}\left [ {{r}^{2}+\left ( {\frac {d\phi} {dt}} \right )^{2}+\left ( {\frac {d\theta} {dt}} \right )^{2}} \right ] ; ;

[0150] in, is the height of the center of mass of the stationary liquid from the tilt axis; c is the height of the pendulum ball from the tilt axis. The height of the tanker truck's sprung center of mass from the tilt axis; ;

[0151] The lateral tilting torque generated by the liquid sloshing about the center of the tank bottom The torque generated by the pendulum ball around the lowest point of the tank The torque generated by the mass of the stationary liquid around the lowest point of the tank composition:

[0152] ; and The expression is as follows:

[0153] ;{M}_{p}={-m}_{p}\left \{{{a}_{p}\cos {\theta}\left [ {{b}_{p}\left ( {{\frac {d\theta} {dt}}^{2}\sin {\theta}-\frac {{d}^{2}\theta} {d{t}^{2}}\cos {\theta}} \right )+\mathrm{g}} \right ]-{a}_{pend}\left ( {b-{b}_{p}\sin {\theta}} \right )} \right \} .

[0154] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, the above-described features have similar functions to (but are not limited to) those disclosed in this application.

Claims

1. A method for constructing test scenarios for an early warning system, characterized in that, Establish a database of static element information in the test scenario; Establish a database of information on different types of risky road sections in the test scenario; Establish a database of basic attribute information for test vehicles; Establish a simulation model for the driving stability of the test vehicle; Acquire dynamic element information; the dynamic element information includes the motion state information and position information of the test vehicle in the actual test scenario, as well as the meteorological information in the vehicle's driving environment; Based on the basic attribute information, static element information, and different types of risky road section information of the test vehicle, the critical safe speed of the test vehicle in the risky road section of the test scenario is obtained through driving stability simulation analysis. Establish a three-stage braking deceleration standard; By acquiring dynamic element information, the critical safe speed of the test vehicle on the risky road section in the test scenario, and the three-level braking deceleration standard in the test scenario, the position of the three-level standard warning signal section is obtained, and the test scenario of the warning system is constructed. When the test vehicle is tested in the warning system test scenario, the location of the braking warning issued by the test vehicle and the instantaneous speed of the test vehicle at the moment of the braking warning are obtained. The effectiveness of the test vehicle's warning system is evaluated by comparing the location of the braking warning issued by the test vehicle with the cross-sectional location of the Level 3 standard warning signal.

2. The method for constructing test scenarios for an early warning system according to claim 1, characterized in that, The static element information includes road network information, road surface information, and static environment information; The road network information includes urban roads, expressways, and mountain roads; the risk road section type information includes sharp bends and steep slopes, sections near water or cliffs, tunnel sections, road surface collapse sections, and bridge sections affected by crosswinds; the road surface information includes dry asphalt pavement, wet and slippery pavement, and icy and snowy pavement. Static environmental information includes obstacles, surrounding landscape, and traffic facilities.

3. The method for constructing test scenarios for an early warning system according to claim 1, characterized in that, The basic attribute information of the test vehicle includes vehicle weight, geometric dimensions, and performance information; The motion status information of the test vehicle includes vehicle speed and vehicle acceleration; The meteorological information of the vehicle's driving environment includes weather temperature, rain, snow, and wind level.

4. The method for constructing test scenarios for an early warning system according to claim 3, characterized in that, The basic attribute information of the test vehicle also includes the shape of the tank and the liquid filling ratio of the cargo inside the tank.

5. The method for constructing a test scenario for an early warning system according to claim 2, characterized in that, The method for obtaining the critical safe speed of the risky road section includes the following steps: when the risky road section is a prohibited road section or a road section with a clearly defined speed limit, the critical safe speed is 0 or the road section speed limit. When the risky road section is a section without a clear speed limit, the critical safe speed is the lowest of the two critical speeds for the test vehicle to avoid skidding and rollover.

6. The method for constructing test scenarios for an early warning system according to claim 5, characterized in that, When the risky road section is a road section with no clear speed limit, the critical speed for skidding and the critical speed for rollover of the test vehicle in the risky road section are obtained based on road network information, risky road section type information, road surface information, basic attribute information of the test vehicle, and motion state information of the test vehicle. The method for obtaining the critical speed for sideslip includes: inputting the basic attribute information of the test vehicle into a driving stability simulation; setting the test vehicle to travel at a constant speed on a road section with no explicit speed limit; setting multiple driving speeds for the test vehicle; obtaining the vehicle's driving trajectory under different driving speed conditions; and the lateral position of the vehicle's front axle center in the Frenet coordinate system with the vehicle's center of mass as the origin. Lateral position of the rear axle center of the vehicle ; Throughout the entire high-risk section, [the following occurred] , The minimum speed corresponding to a value range of 0.2-0.3 is the critical speed for sideslip of the test vehicle on the risky road section; Methods for obtaining the critical rollover speed include: Obtain the rollover risk index and from the starting point of the risky road section Point to the end of the risky road section The probability of rollover on the entire high-risk road section. ; Throughout the entire high-risk section, [the following occurred] , The value range is 0.7-0.9, and , When the value ranges from 0.8 to 0.9, the corresponding minimum speed is the critical speed for the test vehicle to roll over on the risky road section.

7. The method for constructing test scenarios for an early warning system according to claim 6, characterized in that, , The methods for obtaining it include: ; Indicates the length of the road segment. ; ； Indicates the safe rollover speed at a given time. The probability of a vehicle rolling over; This is the maximum set value for the lateral load transfer rate of the axle; exceeding this value is considered an indication that the vehicle has rolled over. The value ranges from 0.8 to 0.9; , The lateral load transfer rate of the axle; the lateral load transfer rate of the axle The driving stability of the test vehicle is obtained through simulation based on the basic attribute information of the test vehicle.

8. The method for constructing test scenarios for an early warning system according to claim 1, characterized in that, The method for obtaining the location of the Level 3 standard early warning signal section in the test scenario includes the following steps: The test scenario includes three standard warning signal section locations: standard easing braking warning signal section location, standard emergency braking warning signal section location, and standard full braking warning signal section location. Three levels of braking deceleration standards are preset in the test scenario; The three-level braking deceleration standards are: mild braking deceleration standard, emergency braking deceleration standard, and full braking deceleration standard; By acquiring the motion state information of the test vehicle in the test scenario, the critical safe speed of the nearest risky road section ahead, and the three-level braking deceleration standard, the standard slow braking warning signal section position, the standard emergency braking warning signal section position, and the standard full braking warning signal section position are obtained according to Formula 1. The deceleration standards for easing braking, emergency braking, and full braking are the 25th, 50th, and 75th percentiles of the distribution of the absolute value of deceleration when a commercial freight truck brakes at an initial speed of medium to high speed. Formula 1 is: ； ； ； The distance from the standard braking warning signal section to the starting point of the corresponding risky road section; The distance from the standard emergency braking warning signal section location to the starting point of the corresponding risky road section; The distance from the standard full braking warning signal section to the starting point of the corresponding risky road section; The braking deceleration standard corresponding to slow braking. The standard for braking deceleration corresponding to emergency braking. The standard braking deceleration corresponding to full braking; It is the maximum road surface adhesion coefficient that the road surface can provide for the vehicle to travel on. The value ranges from 0.2 to 0.85; It is the acceleration due to gravity; To obtain the instantaneous speed of the test vehicle, The critical safe speed for the risky road section; This represents the magnification factor of the braking distance of test vehicles with different liquid filling ratios in their tanks compared to the braking distance of non-liquid cargo vehicles under identical loading conditions; when the liquid filling ratio of the vehicle tank is 0.6~0.8, When the liquid filling ratio of the vehicle tank is less than 0.6 or greater than 0.8, .

9. The method for constructing test scenarios for an early warning system according to claim 8, characterized in that, The method for evaluating the effectiveness of the test vehicle's warning system by comparing the location of the braking warning issued by the test vehicle with the cross-sectional location of the Level 3 standard warning signal includes: Obtain the distance from the location of the braking warning issued by the test vehicle to the starting point of the corresponding risky road segment. ; Calculate the timing of the braking warning issued by the test vehicle , , ; when At that time, the effectiveness of the test vehicle's warning system was evaluated as excellent; when At that time, the effectiveness of the warning system of the test vehicle was evaluated as good; when At that time, the effectiveness of the test vehicle's warning system was evaluated and the result was deemed qualified; when At that time, the effectiveness of the test vehicle's warning system was evaluated as unqualified; To test the effective signal receiving distance of the vehicle warning system.

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