RU2702476C1 - Vehicle overturn prevention method - Google Patents

Abstract

FIELD: motor vehicle industry.

SUBSTANCE: disclosed is method of vehicle overturn prevention. Generating in the information processing unit, in real time, by the time extrapolation method the predicted values of the center of mass velocity, the steering wheel turn angle and the vehicle overturning speed limit value, by mathematical processing of signals on wheels rotation frequencies and adjustment parameters by means of microcontroller with software. Forming, in case of exceeding predicted speed of vehicle center of gravity in comparison with predicted speed of overturn, control actions on accelerator and/or braking system for automatic prevention of vehicle overturning and on indication of braking actuation and transmission to operator information on activation of automatic overturn prevention mode.

EFFECT: enabling prediction and prevention of vehicle overturning.

1 cl, 2 dwg

Description

The invention relates to the automotive industry, in particular, to methods and devices for active safety of all types of trucks and cars, preferably unmanned cargo unmanned vehicles with electric drive (BGTSE).

The preferred area of use is due to the lack of a driver in the BGTSE, which is why the requirements for preventing rollover in real operating conditions increase significantly, especially in turns and when driving a BGTSE on wet road surfaces and the presence of ice.

A known method and system for its implementation, designed to determine the rollover of the vehicle and dangerous situations that may precede the rollover, in particular, the type of rollover caused by a collapse of the ground, which includes the following steps, which are presented in cycles, determining the lateral acceleration of the vehicle, calculation of the derivative of acceleration based on lateral accelerations obtained in at least 2 steps; determination of the possibility of a vehicle overturning based on based on the lateral acceleration obtained in at least one step and the derivative of the acceleration calculated in at least one step, the generation of an activation output signal based at least on the possibility of the vehicle overturning determined in the step. (see US patent US 8046135 B2, applicants DELPHI TECH INC, publ. 25.10.2011).

The main disadvantage of this method is the uncertainty of the necessary braking deceleration to prevent rollover.

A known method and device for preventing lateral rollover of motor vehicles, in which a transverse variable is defined that reflects the transverse dynamics of a motor vehicle, this transverse variable is compared with at least one threshold value and, depending on the comparison result, brake intervention is performed to prevent lateral tipping over. A tilt variable has been established that reflects the lateral tilt of the vehicle body and its threshold value is a function of the tilt variable (see U.S. Pat. No. 9,505,286 B2, Applicants GOETTSCH GERHARD; MERLEIN DOMINIK; BOSCH GMBH ROBERT, published November 29, 2016).

The main disadvantage of this method is the complexity of the sensor part of the system, involving the use of a significant number of sensors, including sensors for wheel speed, lateral acceleration, yaw rate, brake pressure and steering angle.

A known method based on the kinematics of estimating the absolute angle of heel of a vehicle body, in which the absolute angle of heel of the vehicle body is estimated by combining two preliminary estimates of the angle of heel based on their frequency, so that the combined estimate continuously contributes to more accurate preliminary estimates of the angle of heel . The first preliminary estimate of the roll angle is based on the measured roll speed, improved by initially compensating the roll speed signal for the bias error using roll speed estimates obtained from other measured parameters. A second preliminary estimate of the roll angle is determined based on the kinematic relationship between the roll angle, lateral acceleration, yaw rate and vehicle speed. The combined roll angle estimate uses a combining factor that varies with the frequency of the preliminary roll angle signals, and the combining factor used in the combining coefficient is set to different values depending on whether the vehicle is stationary or in transition (see EU patent EP 2127988 A1, Applicant DELPHI TECH INC, publ. 02.12.2009).

The disadvantage of this method is a significant number of measured parameters and a complex data processing procedure for predicting rollover.

The closest in technical essence is the method and system to prevent the rollover of a vehicle in an uneven lane. Traffic images captured by image capturing devices are used to calculate road information. Road information along with vehicle dynamics information, such as vehicle speed and acceleration, is used to predict the tipping angle and lateral acceleration of a vehicle moving in an uneven lane. In the method of preventing the car from rolling over, the signals generated by the pulse sensors of the vehicle’s wheel speeds are recorded and processed and transmitted through the interface unit to the information processing unit, in which the values of such physical variables as the center of mass velocity and the steering wheel angle are determined and compared with the boundary values characterizing the critical condition of the car, and form, in case of exceeding the predicted speed of the center of mass, the value of the predicted speed throwing, at the output of the information processing unit, control signals transmitted to the accelerator and / or brake system control devices and the brake enable indication device. In addition, the height of the center of mass and the critical rollover speed of the vehicle moving along an uneven lane are determined, which are generated and used for determining the rollover index of a vehicle. If the vehicle rollover index exceeds a preset value, the system warns the driver or directly controls the vehicle speed so that the car does not roll over in an uneven lane, (see US patent US 9116784 B2, Applicants AUTOMOTIVE RES & TEST ST, published on 08.25.2015 )

The disadvantage of this method is the limited capabilities of the system, since the main source of information about the parameters of the car’s movement are road images, but this complicates the processing of road images in the dark, rain, fog and bright light sources. The signals generated by the pulse sensors of the vehicle’s wheel speeds are auxiliary in determining the vehicle’s motion parameters and are not decisive for these parameters, which leads to high computational complexity.

The technical problem, the solution of which the invention is directed, consists in indirect measurements, predicting and preventing the rollover of a car.

The stated technical problem is solved by the fact that in the method of preventing the vehicle from capsizing, in which the signals generated by the pulse sensors of the vehicle wheel speed are recorded and transmitted through the interface unit to the information processing unit, in which the values of the physical variables, namely the center speed, are determined masses and the angle of rotation of the steered wheels and compare them with the boundary values characterizing the critical condition of the car, and form, in case of exceeding, we predict at the speed of the center of mass, the values of the predicted rollover speed, at the output of the information processing unit, control signals transmitted to the accelerator and / or brake system control devices and the brake enable indication device, and in the information processing unit in real time, the predicted center speed values are generated by time extrapolation mass, the angle of rotation of the steered wheels of the car and the limit value of the speed of the rollover of the car, by mathematical processing the signal about wheel speeds and tuning parameters using a microcontroller with software, and form, in case of exceeding the predicted speed of the center of mass of the car in comparison with the value of the predicted rollover speed, control actions on the accelerator control device and / or brake system to automatically prevent rollover the car and to the device for indicating the inclusion of braking, designed to transmit to the driver information on the inclusion of automatic About the vehicle rollover prevention mode. The driver is not available in electric unmanned unmanned cargo vehicles, and information about the pre-emergency operation of the BGTSE should be brought to the attention of the operator monitoring the process of movement on the road to take measures to prevent the possibility of emergency situations in other vehicles.

The technical result consists in the dynamic stabilization of the safe speed of the car at bends, due to which the rollover of the car is prevented.

The claimed invention is illustrated by drawings, where:

in FIG. 1 is a flowchart of a vehicle rollover prevention algorithm;

in FIG. 2 presents a kinematic diagram of the movement of a car on a bend.

FIG. 1 contains the computational units of the vehicle rollover prevention algorithm that implements the following method steps:

1 - data input on wheel speeds;

2 - calculation of longitudinal speeds of rotation of the wheels;

3 - calculation of the longitudinal velocity of the center of mass and the difference in the rotational speeds of the pairs of wheels;

4 - calculation of the angle of rotation of the steered wheels;

5 - calculation of the marginal speed of the rollover of the car;

6 - extrapolation over time of the velocity of the center of mass and the marginal velocity of capsizing;

7 - calculation of traction and brake acceleration;

8 - the formation of control actions on the accelerator and brake system;

9 - indication of the inclusion of braking;

10 - data output to external devices.

To implement the method according to the proposed invention, a vehicle rollover prevention system can be used, which includes vehicle wheel speed sensors associated with a communication line interface unit, an information processing unit adapted to receive vehicle wheel speed sensors through communication lines and an interface unit signals and the formation on their basis and on the basis of tuning parameters of the assessment of physical parameters characterizing the state the vehicle, the control actions on the accelerator and / or brake system control devices and the brake actuation indication device, the information input and display unit including the input device for inputting tuning information and selecting the information display mode, the accelerator and / or brake system control device, an indication device braking, a secondary power source that stabilizes and converts the voltage received from the vehicle's on-board network into quantities the voltage required to power the microcontroller, a means of visual display of information.

The method is as follows.

The signals generated by the pulse sensors of the vehicle’s wheel speeds are recorded, processed and transmitted through the interface unit to the information processing unit. In the information processing unit, the values of such physical variables as the speed of the center of mass and the angle of rotation of the steered wheels are determined, and they are compared with boundary values characterizing the critical condition of the car. Namely, in the real-time information processing unit, the predicted values of the center of mass velocity, the steering wheel angle of rotation and the limit value of the vehicle rollover speed are generated by time extrapolation by mathematical processing of the signals about the wheel speeds and tuning parameters using a microcontroller with software, and form, in case of exceeding the predicted velocity of the center of mass of the car in comparison with the magnitude of the predicted rollover speed, control actions on the accelerator and / or brake system control devices for automatically preventing the car from tipping over and on the brake actuation indication device for transmitting information to the driver about the automatic tipping prevent mode activation.

As a mathematical model of indirect measurements of the center of mass of the car speed, V _m, and the steering angle _{Ψ, which} is used a system of wheel rotation speeds of linear equations V _i, 1≤i≤4 in a curve:

ΔV _Si , 1≤i≤4 - the speed of the longitudinal sliding of the wheels;

Δω _m is the angular velocity of drift or skidding of the wheels of the car.

In FIG. 2 adopted the following notation:

b - wheelbase of the car;

Ψ ₁ and Ψ ₂ - rotation angles of the 1st and 2nd steered wheels, respectively;

Ψ _c is the average angle of rotation of the steered wheels;

a ₁ and a ₂ - the gauge of the front and rear wheels;

V _i - the linear speed of rotation of the i-th wheel (1≤i≤4);

R _i are the turning radii of the respective wheels;

R _m and V _m respectively the radius of rotation and the linear velocity of the longitudinal motion of the center of mass;

Ψ _R is the yaw angle;

b ^* is the distance from the center of mass to the rear axle of the vehicle;

ω _m - the angular velocity of rotation of the center of mass of the car at a bend when driving without drift or skidding.

формируются по данным измерений частот вращения колес ω_i(k) и настроечных данных свободных радиусов R_ci(k) колес.Grades

are formed according to measurements of wheel speeds ω _i (k) and tuning data of free radii R _ci (k) of the wheels.

(1≤i≤4) по известным оценкам

настроечным параметрам b, a ₁≈а, а ₂≈а при Δω_m=0 приведено в алгоритме определенных параметров движения автомобиля (Свидетельство об государственной регистрации программы для ЭВМ №2009616286. ИНКА-СПОРТ Версия 2.0 / Бузников С.Е., Елкин Д.С. // Роспатент, 2009).Solving the incorrect task of determining grades

(1≤i≤4) according to well-known estimates

the tuning parameters b, a ₁ ≈ a , and ₂ ≈ a for Δω _m = 0 are given in the algorithm for certain vehicle motion parameters (Certificate of state registration of a computer program No. 20099616286. INCA-SPORT Version 2.0 / Buznikov S.E., Elkin D .S. // Rospatent, 2009).

определяется в виде:So, in particular, the estimation of the longitudinal velocity of the center of mass

defined as:

where | ΔV _Si (k) + ΔV _Sj (k) | = min [| ΔV _S1 (k) + ΔV _S2 (k) |, | ΔV _S3 (k) + ΔVS ₄ (k) |, | ΔV _S1 (k ) + ΔV _S4 (k) |, | ΔV _S2 (k) + ΔV _S3 (k) |].

For a pair of wheels of different sides, the difference ΔV _{i, j} = V _i -V _j is equal to:

и ΔV_Si=ΔV_Sj=0:Solution (3) in the case of

and ΔV _Si = ΔV _Sj = 0:

получим, что:Accepting grade

we get that:

The case of a car overturning on a smooth horizontal surface is considered under the condition that the boundary speed of the rollover is less than the boundary speeds of drift and skidding of the wheels and, therefore, Δω _m = 0.

The boundary tipping speed V _gr0 is determined from the equality of the tipping and returning moments, and is:

h _m - the height of the center of mass of the car.

Prediction of the occurrence of a vehicle rollover is performed by extrapolating the boundary predicted rollover speed V _gr0 and the predicted center of mass velocity V _m over time τ _e and verify the inequality:

In case inequality (8) is satisfied, accelerator and / or brake system control devices and a graphic information output device are activated.

The extrapolation time τ _e includes the time for predicting the occurrence of the rollover event and the delay time introduced due to the finite speed of the computing device and the delay of the accelerator and / or brake system control devices.

The value of the traction and brake acceleration a _dT sufficient to prevent drift or skidding of the vehicle’s wheels is determined by solving the equation of longitudinal motion of the vehicle’s center of mass:

k _x - coefficient of frontal aerodynamic drag;

k _Tr - coefficient of friction of rolling wheels;

α _T - pitch angle of the car.

из (9) получим величину α_dT:At

from (9) we obtain the value of α _dT :

In the case of movement on a horizontal surface α _T = 0, and neglecting the forces of aerodynamic drag and rolling friction, we obtain approximately:

The distribution of traction and deceleration between the engine, transmission and brake system is carried out in accordance with the characteristics of these systems.

The described sequence of steps of the method and the minimum number of technical means used for its implementation allows to achieve the following technical advantages over known methods:

- the ability to predict and prevent the rollover of a car before the occurrence of this event;

- low cost of technical equipment, due to the presence of only full-time physical sensors of primary information necessary and sufficient to solve the problem;

- the possibility of functioning in an incomplete configuration of wheel speed sensors, including failures of one or two sensors of different sides of the car;

- reduced power consumption due to the use of only full-time sensors to obtain information;

- higher operational reliability, due to the minimum configuration of the used technical means, including standard primary information sensors;

- the lack of influence of the state of the external environment, including illumination, precipitation, fog, etc., on the efficiency of the system;

- the ability to use the method to automatically prevent rollovers of vehicles, including unmanned cargo vehicles without cabs.

Claims (1)

A method of preventing a vehicle rollover, in which the signals generated by the pulse sensors of the vehicle’s wheel speeds are recorded and processed and transmitted through the interface unit to the information processing unit, in which the values of the physical variables, namely the speed of the center of mass and the angle of rotation of the steered wheels, are determined, and compare them with the boundary values characterizing the critical condition of the car, and form, if the predicted speed of the center of mass exceeds the value of the predicted speed tipping rollers, at the output of the information processing unit, control signals transmitted to the accelerator and / or brake system control devices and a brake enable indication device, characterized in that in the information processing unit in real time, the predicted values of the velocity of the center of mass, the angle are formed by time rotation of the steered wheels of the car and the limit value of the speed of the rollover of the car, by mathematical processing of signals about the frequencies of rotation of the wheels and tuning parameters using the microcontroller with software, and form, in case of exceeding the predicted speed of the center of mass of the car in comparison with the predicted speed of rollover, the control actions on the accelerator control device and / or the brake system to automatically prevent the car from tipping over and on the brake actuation indication device and transmitting information to the operator about the inclusion of an automatic rollover prevention mode.

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