A special vehicle rollover early warning method and system under non-structural pavement

Abstract

The application discloses a kind of special vehicle rollover early warning method and system under non-structural pavement, belong to vehicle safety technical field, comprising: obtaining vehicle structure parameter, according to vehicle structure parameter, calculate the demarcation point of three stages of vehicle roll movement process, three stages are spring mass roll stage, wheel off ground roll-gravity inhibition roll stage and wheel off ground roll-gravity acceleration roll stage;According to demarcation point, construct vehicle three-stage roll dynamics equation;According to vehicle three-stage roll dynamics equation and the vehicle state information collected in real time, update the predicted roll state sequence of next time period;According to the predicted roll state sequence of next time period, in combination with the risk degree of three stages of vehicle roll movement process, carry out two-section roll early warning.The application is combined with the roll dynamics evolution equation of three stages and two-section early warning scheme, effectively solve the problem of inaccurate vehicle roll state prediction, and the problem of not timely warning.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle safety, more particularly, to a special vehicle rollover warning method and system under unstructured road surface. BACKGROUND

[0002] With the wide application of special vehicles in emergency rescue, military transportation, field exploration and other fields, the driving safety problem under unstructured road surface (such as muddy, gravel, steep slope and other complex terrain) is increasingly prominent. Compared with structured road surface, the dynamic characteristics of unstructured road surface significantly aggravate the nonlinear characteristics of vehicle roll dynamics behavior, especially the multi-body coupling interference among vehicle body, road surface and load. These complex conditions make it difficult for the traditional rollover prevention warning method based on static threshold or linear dynamics model to accurately capture the critical state of vehicle roll stability, which easily leads to warning delay or misjudgment, and thus threatens the driving safety of special vehicles.

[0003] In patent number "CN103921719A", a vehicle rollover warning method based on lateral acceleration monitoring is disclosed. The technical solution acquires the lateral acceleration data of the vehicle in real time, compares it with the preset critical lateral acceleration threshold, and then triggers the corresponding level of warning signal according to the comparison result. However, the existing technical solution has the following technical limitations: the warning judgment only relies on the single lateral acceleration sensor data, lacks comprehensive analysis of multi-dimensional parameters, and thus the warning accuracy and reliability are limited, which may lead to misjudgment or omission under complex driving conditions.

[0004] Based on the analysis of the existing technology, the current rollover prevention warning of special vehicles mainly relies on the roll dynamics equation for deduction, but the wheel off-road phenomenon occurs from time to time under unstructured road surface, so it is necessary to establish a vehicle roll dynamics model including the wheel off-road condition for realizing the rollover safety warning of special vehicles. SUMMARY

[0005] Therefore, the present application provides a special vehicle rollover warning method and system under unstructured road surface, which realizes the state deduction after single wheel off-road based on three-stage roll dynamics evolution equation, and adopts two-section warning scheme, effectively solving the problems of inaccurate vehicle roll state prediction and untimely warning.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme:

[0007] On the one hand, the present application provides a special vehicle rollover warning method under unstructured road surface, comprising:

[0008] Obtaining vehicle structure parameters, calculating the demarcation points of three stages of vehicle roll motion process according to the vehicle structure parameters, the three stages being sprung mass roll stage, wheel-off ground roll-gravity suppression roll stage and wheel-off ground roll-gravity acceleration roll stage;

[0009] Constructing vehicle three-stage roll dynamics equation according to the demarcation points;

[0010] Updating the predicted roll state sequence of the next time period according to the vehicle three-stage roll dynamics equation and the real-time collected vehicle state information;

[0011] According to the predicted roll state sequence of the next time period, combining the danger degree of the three stages of vehicle roll motion process, two-stage roll warning is carried out.

[0012] Preferably, the demarcation points of three stages of vehicle roll motion process are calculated according to the vehicle structure parameters, comprising:

[0013] In the stable lateral understeering acceleration Next, the critical roll angle of the demarcation point between the sprung mass roll stage and the wheel-off ground roll-gravity suppression roll stage is calculated according to the geometric relationship of the vehicle body posture and the kinematics relationship of the sprung mass The critical roll angle The calculation formula is:

[0014] ;

[0015] Wherein, is the lateral acceleration of the vehicle, is the body width, is the height of the sprung mass center to the roll center, is the roll angle, is the gravity acceleration, is the height of the sprung mass center to the ground, is the sprung mass, is the roll stiffness of the vehicle;

[0016] According to the static rollover characteristics of the vehicle, the demarcation point static rollover coefficient of the wheel-off ground roll-gravity suppression roll stage and the wheel-off ground roll-gravity acceleration roll stage is solved:

[0017] .

[0018] Preferably, the vehicle three-stage roll dynamics equation is constructed according to the demarcation points, comprising: in the state that the wheels are not off the ground, the vehicle is in the sprung mass roll stage, based on the sprung mass dynamics analysis, the roll-over resisting torque generated by the roll-over resisting spring and the roll-over resisting damping is analyzed as an external force, and the sprung mass roll stage roll dynamics equation is obtained.

[0019] In the wheel-off state, the vehicle is in the whole vehicle roll stage, at this time the vehicle center coordinate on the ground projection point does not exceed the single-sided tire contact point position, based on the d'Alembert principle analysis, the lateral acceleration and gravity acceleration are analyzed as external force, the wheel-off roll-gravity inhibition roll stage roll dynamics equation is obtained;

[0020] In the wheel-off state, the vehicle is in the whole vehicle roll stage, at this time the vehicle center coordinate on the ground projection point exceeds the single-sided tire contact point position, based on the d'Alembert principle analysis, the lateral acceleration and gravity acceleration are analyzed as external force, the wheel-off roll-gravity acceleration roll stage roll dynamics equation is obtained;

[0021] The vehicle three-stage roll dynamics equation is obtained by comprehensively considering the spring mass roll stage roll dynamics equation, the wheel-off roll-gravity inhibition roll stage roll dynamics equation, and the wheel-off roll-gravity acceleration roll stage roll dynamics equation:

[0022] ;

[0023] Wherein, I represents the moment of inertia of the vehicle around the axis, I represents the moment of inertia of the vehicle around the tire contact point position after one side of the vehicle wheel is off the ground, L represents the distance from the center of mass to the tire contact point position after one side of the vehicle wheel is off the ground, Sgn represents the sign function.

[0024] Preferably, the predicted roll state sequence of the next time period is updated according to the vehicle three-stage roll dynamics equation and the real-time collected vehicle state information, including:

[0025] The continuous time domain vehicle three-stage roll dynamics equation is converted into a discrete time domain vehicle three-stage roll dynamics equation by using the Euler discrete method;

[0026] The discrete time step of the predicted time period is selected, and all the predicted roll state sequences in the predicted time period are calculated.

[0027] Preferably, according to the predicted roll state sequence of the next time period, combined with the three-stage danger degree of the vehicle roll movement process, a two-stage roll warning is carried out, including:

[0028] In the spring mass roll stage, the lateral load transfer rate at future k time calculated by the roll angle and the roll angular velocity in the predicted roll state sequence is used as a warning index, and compared with the preset lateral load transfer rate threshold value, to determine whether to issue a T1 roll warning;

[0029] In the wheel-offside-bank-gravity-restraining-bank stage, a stable envelope line discrimination method of the bank angle-bank angular velocity phase plane is adopted to depict the bank angle-bank angular velocity phase plane image, to divide the stable domain and the unstable domain, to determine whether the vehicle state is located in the stable domain according to the predicted bank state sequence, and to determine whether to maintain the T1 bank early warning or to change to the T2 bank early warning in combination with the activation state of the T1 bank early warning.

[0030] In another aspect, the present application provides a special vehicle rollover early warning system under non-structural road surface, which is used for the above-mentioned special vehicle rollover early warning method under non-structural road surface, and comprises:

[0031] A data acquisition module is configured to acquire vehicle structure parameters and vehicle state information.

[0032] An analysis module is configured to calculate the dividing points of three stages of vehicle bank movement process according to the vehicle structure parameters, the three stages being a sprung mass bank stage, a wheel-offside-bank-gravity-restraining-bank stage, and a wheel-offside-bank-gravity-acceleration-bank stage, to construct a vehicle three-stage bank dynamics equation according to the dividing points, and to update the predicted bank state sequence of the next time period according to the vehicle three-stage bank dynamics equation and the real-time acquired vehicle state information.

[0033] An early warning module is configured to perform two-stage bank early warning according to the predicted bank state sequence of the next time period and in combination with the risk degree of the three stages of vehicle bank movement process.

[0034] Preferably, the data acquisition module comprises:

[0035] An input unit is configured to acquire vehicle structure parameters.

[0036] A vehicle-mounted sensor is configured to acquire vehicle state information.

[0037] A filter is configured to perform filtering processing on the vehicle state information.

[0038] Preferably, the early warning module comprises:

[0039] A display unit is configured to visually output an early warning signal.

[0040] A sound output unit is configured to acoustically output an early warning signal.

[0041] Compared with the prior art, the application provides a roll warning method and system based on three-stage vehicle roll dynamics, and the state deduction after single wheel off the ground is realized based on the three-stage roll dynamics evolution equation, effectively solving the problem of inaccurate vehicle roll state prediction. Meanwhile, the application adopts a two-stage warning scheme, effectively improving the driving safety performance of special vehicles, avoiding psychological panic of the driver caused by one-time warning, and further causing greater losses. Compared with the traditional roll warning scheme, the roll warning precision of the application is higher, the algorithm structure is simple, and the prediction accuracy is high. Meanwhile, the method represents the vehicle roll state after the wheel off the ground, effectively improving the effective performance of the roll warning. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on the provided drawings.

[0043] Figure 1 The flowchart for implementing the roll warning in the present application.

[0044] Figure 2 The three-stage roll dynamics diagram proposed in the present application.

[0045] Figure 3(a) is the roll angle-roll angular velocity phase plane and safety envelope range under the lateral acceleration 0m / s in the present application, Figure 3(b) is the roll angle-roll angular velocity phase plane and safety envelope range under the lateral acceleration 3m / s in the present application, and Figure 3(c) is the roll angle-roll angular velocity phase plane and safety envelope range under the lateral acceleration 6m / s in the present application. 2 2 2

[0046] Figure 4 The structure diagram of the vehicle roll warning system proposed in the present application. DETAILED DESCRIPTION

[0047] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0048] ​​​This invention discloses a roll warning method and system based on three-stage vehicle roll dynamics. The roll motion of a vehicle caused by lateral acceleration can be summarized into three stages: the sprung mass roll stage (A1), the wheel-off-ground roll-gravity-restraint roll stage (A2), and the wheel-off-ground roll-gravity-acceleration roll stage (A3). Although the wheel-off-ground roll-gravity-restraint roll stage involves wheel lift-off, not all conditions will cause vehicle instability; therefore, a brief period of vehicle instability in this stage is permissible.

[0049] This invention discloses a method for early warning of rollover of special vehicles on unstructured road surfaces, such as... Figure 1 As shown, it includes:

[0050] Obtain vehicle structural parameters and calculate the boundary points of the three stages of the vehicle's roll motion process based on the vehicle structural parameters. The three stages are the sprung mass roll stage, the wheel-off-ground roll-gravity-restrained roll stage, and the wheel-off-ground roll-gravity-accelerated roll stage.

[0051] Construct a three-stage roll dynamics equation for the vehicle based on the dividing point;

[0052] The predicted roll state sequence for the next time period is updated based on the vehicle's three-stage roll dynamics equation and real-time vehicle state information.

[0053] Based on the predicted roll state sequence for the next time period, and combined with the three stages of danger in the vehicle roll motion process, a two-stage roll warning is implemented.

[0054] Furthermore, based on vehicle structural parameters, the dividing points of the three stages of the vehicle's roll motion process are calculated, including:

[0055] The dividing point between stages A1 and A2 is when the wheels are off the ground. At this point, the problem can be solved using the vehicle's dynamic rollover characteristics, which specifically include:

[0056] Stable horizontal acceleration Below, based on the geometric relationship of the vehicle body posture and the kinematic relationship of the sprung mass, the critical roll angle at the boundary between the sprung mass roll stage and the wheel-off-ground roll-gravity-restrained roll stage is calculated. Critical roll angle The calculation formula is:

[0057] ;

[0058] in, It is the vehicle's lateral acceleration. For vehicle width, The height from the sprung center of mass to the roll center. The roll angle is... It is the acceleration due to gravity. is the height of the sprung mass center to the ground, is the sprung mass, is the roll stiffness of the vehicle;

[0059] According to the vehicle static roll characteristics, the demarcation point static roll coefficient of the wheel-off roll-gravity suppression roll stage and the wheel-off roll-gravity acceleration roll stage is solved :

[0060] .

[0061] Further, with reference to Figure 2 , the vehicle three-stage roll dynamics equation is constructed according to the demarcation point, including: in the wheel-off state, the vehicle is in the sprung mass roll stage, based on the sprung mass dynamics analysis, the roll-resisting moment generated by the roll-resisting spring and the roll-resisting damping is analyzed as an external force, and the roll dynamics equation of the sprung mass roll stage is obtained;

[0062] In the wheel-off state, the vehicle is in the whole vehicle roll stage, at this time, the vehicle center coordinate on the ground projection point does not exceed the single-sided tire contact point position, based on the d'Alembert principle analysis, the inertial force such as anti-lateral acceleration and gravity acceleration is analyzed as an external force, and the roll dynamics equation of the wheel-off roll-gravity suppression roll stage is obtained;

[0063] In the wheel-off state, the vehicle is in the whole vehicle roll stage, at this time, the vehicle center coordinate on the ground projection point exceeds the single-sided tire contact point position, based on the d'Alembert principle analysis, the inertial force such as anti-lateral acceleration and gravity acceleration is analyzed as an external force, and the roll dynamics equation of the wheel-off roll-gravity acceleration roll stage is obtained;

[0064] The vehicle three-stage roll dynamics equation is obtained by comprehensively considering the roll dynamics equation of the sprung mass roll stage, the roll dynamics equation of the wheel-off roll-gravity suppression roll stage, and the roll dynamics equation of the wheel-off roll-gravity acceleration roll stage:

[0065] ;

[0066] wherein, represents the moment of inertia of the vehicle around the axis, represents the moment of inertia of the vehicle around the tire contact point position after one side of the vehicle wheel is off the ground, , represents the distance from the center of mass to the tire contact point position after one side of the vehicle wheel is off the ground, represents the sign function.

[0067] In another embodiment, the predicted roll state sequence of the next time period is updated according to the three-stage roll dynamics equation of the vehicle and the real-time collected vehicle state information, including:

[0068] The continuous-time three-stage roll dynamics equation of the vehicle is converted into a discrete-time three-stage roll dynamics equation of the vehicle by using the Euler discretization method; in this embodiment, the forward Euler formula is used for conversion, as follows:

[0069]

[0070] wherein, is the discrete time, is the differential equation of the system, i.e., the three-stage roll dynamics equation of the vehicle.

[0071] The number of discrete time steps of the prediction time period is selected, and all predicted roll state sequences in the prediction time period are calculated.

[0072] Further, the vehicle roll state prediction information after time k is obtained by updating the system update equation as follows: and the predicted k time is calculated according to the information combined with the forward Euler formula. It should be particularly noted that when the forward Euler formula is used to update the vehicle roll dynamics state, the input of the system differential equation needs to be provided, and in this example, two processing methods are provided.

[0073] First, to simplify the calculation process and improve the real-time performance of the system, the external input of the forward Euler formula in this embodiment is defined as the directly measurable lateral acceleration . This parameter has a significant advantage: the inertial measurement unit (IMU) commonly equipped in modern vehicles can directly output the lateral acceleration signal without complex intermediate calculation, greatly reducing the system implementation complexity. To establish a theoretical analysis model, without loss of generality, it is assumed that the lateral acceleration remains constant (i.e., ) within a single calculation period , and the vehicle roll angle state quantity at the subsequent time can be recursively solved through this constant input. It should be particularly noted that in actual engineering applications, the original signal output by the vehicle-mounted acceleration sensor usually contains high-frequency noise (typical frequency band > 20 Hz) introduced by road excitation, braking vibration, etc., and direct use will cause significant chattering in state prediction. Preferably, a fourth-order Butterworth low-pass filter with a cutoff frequency is used for preprocessing in this embodiment, which has the maximum flat amplitude characteristic in the passband and can effectively suppress high-frequency noise while maintaining the integrity of key dynamic information.

[0074] ​Secondly, to improve the prediction accuracy of the vehicle roll dynamics model, this embodiment innovatively incorporates the input of the forward Euler formula. Defined as front wheel steering angle This parameter can be obtained in two ways: (1) by directly reading the front wheel angle sensor data provided by the electric power steering (EPS) system; (2) by measuring the steering wheel angle. via steering ratio Conversion ( Compared to the lateral acceleration input scheme, this scheme has unique anti-interference advantages: the steering angle signal itself is not affected by vehicle vibration, and there is no high-frequency noise interference during signal acquisition (measured signal-to-noise ratio > 60dB). Therefore, the Butterworth filtering stage can be completely eliminated, fundamentally eliminating the phase lag problem caused by filtering in traditional schemes (typical delay time ≈ 50ms), and significantly reducing the risk of "missed alarms" caused by signal delay. It should be noted that since the original roll equation does not explicitly include the front wheel steering angle variable, this embodiment establishes the coupling relationship between the two by introducing the following vehicle model:

[0075] ;

[0076] in, These represent the lateral forces on the left front wheel, right front wheel, left rear wheel, and right rear wheel, respectively. These lateral forces can be calculated using the Magic Tire formula, as follows:

[0077] ;

[0078] in, These are the current lateral and vertical forces on the tire, measured in kN. B, C, D, and E are empirical parameters. It is the tire slip angle, calculated using the following formula:

[0079] ;

[0080] In another embodiment, based on the predicted roll state sequence for the next time period and combined with the three-stage danger level of the vehicle roll motion process, a two-stage roll warning is performed, including:

[0081] First, the indicators for the two-stage early warning scheme are determined. Based on the analysis of the three-stage vehicle roll dynamics equation, it can be concluded that stages A1 and A2 are both stable roll states, while stage A3 is a roll instability stage. Therefore, based on the above analysis, early warning indicators corresponding to stages A1 and A2 are established respectively.

[0082] Furthermore, in stage A1, the vehicle is in a state where the tires are not off the ground. At this time, the sprung roll dynamics are the main characteristic of the vehicle's roll state, so the lateral load transfer rate (LTR) is used for prediction.

[0083] Preferably, the roll angle and roll angular velocity in the predicted state sequence are used to calculate the future. The lateral load transfer rate at time t is calculated as follows:

[0084] ;

[0085] By selecting a reasonable LTR threshold This ensures the effectiveness of the A1 stage warning. Specifically, when the value is below the threshold, the vehicle is within the safe range of the A1 stage and no warning is issued. When the value is above the threshold, the vehicle issues a T1 roll warning. At this time, the vehicle actuators are slightly operated to ensure that the vehicle's driving state is as close as possible to the driver's intention. At the same time, the vehicle's roll state is corrected and a T1 prompt signal is issued to the driver.

[0086] Furthermore, the maximum prediction time in stage A1 is selected. This parameter is defined as the maximum look-ahead time that the early warning system can predict in the A1 phase, used to determine... and If the condition is met, it means that there will be no roll risk during the specified A1 stage roll prediction time period, and the vehicle will output a no-roll risk signal (or no warning will be issued); if... This indicates that the vehicle is at risk of A1 stage roll, and a T1 roll warning message is output. The T1 roll warning message serves as a reminder to the driver to pay attention to driving safety, and it can also be used as a switch signal for the anti-roll controller. Afterwards... The vehicle status information is updated at each moment, and the above process is repeated until the system reaches its maximum prediction look-ahead time. .

[0087] Once the warning system enters the T1 roll warning stage (A1 phase), it triggers the A2 phase roll warning procedure. The A2 phase warning procedure is similar to the A1 phase, both determining the vehicle's position based on boundary conditions. Whether the roll risk of stage A2 occurs at any given moment is important. The judgment of roll risk in stage A2 differs from that in stage A1 in two aspects.

[0088] Firstly, unlike the roll risk warning in stage A1 which uses lateral load transfer rate for risk assessment, the roll risk assessment in stage A2 uses a roll angle-roll rate-roll angular velocity-based method. Methods for determining the stable envelope of the phase plane. There are several ways to express the stable envelope, including the double-line method, the equivalent circle method, and the rhombus method. This example uses the rhombus method. It should be noted that other expressions of the stable envelope are variations of this example and are therefore also considered within its scope. Roll angle - roll velocity The phase plane is detailed in Figures 3(a)-3(c). The algorithm for dividing the stable boundary is as follows:

[0089] Algorithm 1: Obtaining the stable boundary of the rhombus;

[0090] Input: Three-stage roll kinematics equations for the vehicle;

[0091] Output: Rhomboid stable boundary line equations;

[0092] Calculate the saddle point location information to obtain the saddle point coordinates. and ;

[0093] Find the outermost phase trajectory curve that converges to the stable point at the boundary, denoted as... and ;

[0094] Separately and Plot curves and Tangent, denoted as and .

[0095] curve and about Draw symmetrical lines and Finally, a closed rhombus-shaped interval is formed, denoted as region. .

[0096] Secondly, the A2 stage roll risk warning mechanism of this system is fundamentally different from that of the A1 stage. As the highest level of the graded warning system, the triggering of the A2 warning requires two conditions: (1) the A1 warning has been continuously activated; (2) the vehicle's dynamic state exceeds the stability boundary. Specifically, when the system is in Predicted state vector at time step satisfy:

[0097] Stable operating conditions ( );

[0098] Although at this time it is satisfied The stability criterion is used, but since the system has entered the A2 early warning monitoring phase, it will maintain the T1 early warning state (LED indicator flashing continuously + intermittent buzzer alarm). This conservative strategy stems from the fact that when approaching the rollover critical point, even if the current state variables are temporarily in the stable region... Within it, its dynamic trajectory may be rapidly approaching an unstable boundary.

[0099] Critical operating conditions ( );

[0100] When the state quantity breaks through the defined stable boundary, the system immediately upgrades to T2 warning (LED red constant + buzzer continuous high-frequency ringing), and displays the "rollover risk! Automatic deceleration" prompt information through the human-machine interface. At the same time, the vehicle controller executes three-level safety intervention:

[0101] ① Apply brake torque through electronic stability program (ESP) to linearly reduce vehicle speed to threshold value within 3 seconds (Calculation formula: ), wherein is the road adhesion coefficient, is the turning radius);

[0102] ② Activate engine torque limit, output power reduced to 30% of rated value;

[0103] ③ If the steering wheel angle rate > 90° / s is monitored, the steering auxiliary torque is simultaneously triggered to multiply;

[0104] Summarizing the above warning process, first, the time length is predicted, and the lateral load transfer rate in this time period is calculated according to the three-stage vehicle roll dynamics equation If the average lateral load transfer rate in the time length is satisfied, no roll risk warning is performed; otherwise, if the average lateral load transfer rate in the time length appears, that is, the roll risk occurs in the A1 stage, T1 warning is performed, and the A2 stage risk judgment is entered. In the A2 stage risk judgment, the time length is predicted, and if the average lateral load transfer rate in the time length is satisfied, T1 warning is performed; otherwise, if the average lateral load transfer rate in the time length appears, that is, the roll risk occurs in the A2 stage, T2 warning is performed. As shown in Table 1:

[0105] Table 1 Warning state under different states

[0106]

[0107] On the other hand, the present application provides a special vehicle roll warning system under non-structural road surface, which is used for any of the above special vehicle roll warning methods under non-structural road surface, as shown in Figure 4 , comprising:

[0108] A data acquisition module for acquiring vehicle structure parameters and vehicle state information;

[0109] The analysis module is configured to calculate a demarcation point of a three-stage process of vehicle roll motion according to vehicle structure parameters, the three stages being a sprung mass roll stage, a wheel-off ground roll-gravity suppression roll stage, and a wheel-off ground roll-gravity acceleration roll stage; construct a vehicle three-stage roll dynamics equation according to the demarcation point; and update a predicted roll state sequence of a next time period according to the vehicle three-stage roll dynamics equation and real-time collected vehicle state information.

[0110] The early warning module is configured to perform two-stage roll early warning according to the predicted roll state sequence of the next time period and in combination with a dangerous degree of the three stages of the vehicle roll motion process.

[0111] Preferably, the data collection module comprises:

[0112] The input unit is configured to acquire vehicle structure parameters.

[0113] The vehicle-mounted sensor is configured to acquire vehicle state information.

[0114] The filter is configured to perform filtering processing on the vehicle state information.

[0115] Preferably, the early warning module comprises:

[0116] The display unit is configured to visually output an early warning signal.

[0117] The sound output unit is configured to acoustically output an early warning signal.

[0118] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts of various embodiments can be mutually referred to. For the device disclosed by the embodiments, since it corresponds to the method disclosed by the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0119] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rollover warning method for special vehicles under non-structural road surface, characterized in that, The method comprises the following steps: acquiring vehicle structure parameters, calculating the demarcation points of three stages of vehicle roll motion according to the vehicle structure parameters, the three stages being sprung mass roll stage, wheel-off-ground roll-gravity suppression roll stage and wheel-off-ground roll-gravity acceleration roll stage; constructing vehicle three-stage roll dynamics equation according to the demarcation points; updating the predicted roll state sequence of the next time period according to the vehicle three-stage roll dynamics equation and the real-time collected vehicle state information; carrying out two-stage roll warning according to the predicted roll state sequence of the next time period and in combination with the danger degree of the three stages of vehicle roll motion.

2. The vehicle roll-over warning method for special vehicles on unstructured road surfaces according to claim 1, characterized in that, The method for calculating the demarcation points of three stages of vehicle roll motion according to the vehicle structure parameters comprises the following steps: In the stable lateral acceleration Next, the critical roll angle of the dividing point between the roll stage of the sprung mass and the roll stage of the wheel lift and gravity suppression of the unsprung mass is calculated in combination with the geometric relation of the vehicle body posture and the kinematic relation of the sprung mass , the critical roll angle The calculation formula is: wherein is the lateral acceleration of the vehicle, is the vehicle body width, is the height of the sprung mass center to the roll center, is the roll angle, is the gravitational acceleration, is the height of the sprung mass center to the ground, is the sprung mass, is the roll stiffness of the vehicle; The demarcation point static roll coefficient of the wheel-off-ground roll-gravity roll stage and the wheel-off-ground roll-gravity acceleration roll stage is solved according to the vehicle static roll characteristics : 。 3. The vehicle roll-over warning method for non-structural road surface according to claim 2, wherein, The method for constructing vehicle three-stage roll dynamics equation according to the demarcation points comprises the following steps: in the wheel-off-ground state, the vehicle is in the sprung mass roll stage, the roll-inhibiting torque generated by the roll-inhibiting spring and roll-inhibiting damping is analyzed as external force based on the analysis of sprung mass dynamics, and the sprung mass roll stage roll dynamics equation is obtained; in the wheel-off-ground state, the vehicle is in the whole vehicle roll stage, at this time, the vehicle center coordinate projection point on the ground does not exceed the single-side tire contact point position, the anti-lateral acceleration and gravity acceleration are analyzed as external force based on the analysis of D'Alembert principle, and the wheel-off-ground roll-gravity suppression roll stage roll dynamics equation is obtained; in the wheel-off-ground state, the vehicle is in the whole vehicle roll stage, at this time, the vehicle center coordinate projection point on the ground exceeds the single-side tire contact point position, the anti-lateral acceleration and gravity acceleration are analyzed as external force based on the analysis of D'Alembert principle, and the wheel-off-ground roll-gravity acceleration roll stage roll dynamics equation is obtained; the vehicle three-stage roll dynamics equation is obtained by comprehensively considering the sprung mass roll stage roll dynamics equation, the wheel-off-ground roll-gravity suppression roll stage roll dynamics equation and the wheel-off-ground roll-gravity acceleration roll stage roll dynamics equation: ； wherein Izdenotes the moment of inertia of the vehicle about the z-axis, Izdenotes the moment of inertia of the vehicle about the z-axis, Izdenotes the moment of inertia of the vehicle about the z-axis, Izdenotes the moment of inertia of the vehicle about the z-axis, Izdenotes the moment of inertia of the vehicle about the z-axis, 4. The vehicle roll-over warning method for special vehicles on unstructured road surfaces according to claim 1, characterized in that, The method for updating the predicted roll state sequence of the next time period according to the vehicle three-stage roll dynamics equation and the real-time collected vehicle state information comprises the following steps: the Euler discrete method is adopted to convert the continuous time domain vehicle three-stage roll dynamics equation into discrete time domain vehicle three-stage roll dynamics equation; the discrete time step of the predicted time period is selected, and all the predicted roll state sequences in the predicted time period are calculated.

5. The vehicle roll-over warning method for special vehicles on unstructured road surfaces according to claim 1, characterized in that, The method for carrying out two-stage roll warning according to the predicted roll state sequence of the next time period and in combination with the danger degree of the three stages of vehicle roll motion comprises the following steps: in the sprung mass roll stage, the lateral load transfer rate of the future k time calculated by the roll angle and roll angular velocity in the predicted roll state sequence is taken as the warning index, and compared with the preset lateral load transfer rate threshold value, whether to issue T1 roll warning is judged; In the wheel-offside-bank-gravity-restrain-bank stage, the stable envelope method of the bank angle-bank angular velocity phase plane is adopted to depict the bank angle-bank angular velocity phase plane image, to divide the stable domain and the unstable domain, to determine whether the vehicle state is located in the stable domain according to the predicted bank state sequence, and to determine whether to maintain the T1 bank early warning or to change to the T2 bank early warning in combination with the activation state of the T1 bank early warning.

6. A roll-over warning system for a special vehicle under non-structural pavement, characterized in that, The system is used to realize the special vehicle rollover early warning method under the unstructured road surface as claimed in any one of claims 1-5, and comprises: a data acquisition module for acquiring vehicle structure parameters and vehicle state information; an analysis module for calculating the dividing points of three stages of vehicle bank movement process according to the vehicle structure parameters, the three stages being the sprung mass bank stage, the wheel-offside-bank-gravity-restrain-bank stage and the wheel-offside-bank-gravity-acceleration-bank stage, for constructing the vehicle three-stage bank dynamics equation according to the dividing points, and for updating the predicted bank state sequence of the next time period according to the vehicle three-stage bank dynamics equation and the real-time collected vehicle state information; an early warning module for performing two-stage bank early warning according to the predicted bank state sequence of the next time period and in combination with the danger degree of the three stages of vehicle bank movement process.

7. The vehicle roll-over warning system according to claim 6, wherein, The data acquisition module comprises: an input unit for acquiring vehicle structure parameters; an on-board sensor for acquiring vehicle state information; a filter for filtering the vehicle state information.

8. The roll-over warning system for a special vehicle under unstructured road surface according to claim 6, characterized in that, The early warning module comprises: a display unit for visualizing the early warning signal output; a sound output unit for acoustic early warning signal output.

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