Method for controlling a motor vehicle in the event of the vehicle starting to tilt
The EPS and ESP system uses existing vehicle sensors to apply steering and counter-steering torques to counteract tipping forces and regain vehicle control in extreme situations.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- STELLANTIS AUTO SAS
- Filing Date
- 2025-10-07
- Publication Date
- 2026-05-15
AI Technical Summary
Existing vehicle stability systems, such as ESP, are ineffective in extreme situations like brutal side collisions that cause the vehicle to become momentarily unbalanced on two wheels, leading to potential rollovers.
A method involving an EPS and ESP system that applies a steering torque in the direction of tipping followed by a counter-steering torque when the roll angle exceeds a critical threshold, using existing vehicle sensors to regain control.
Effectively counters the tipping force and brings the vehicle back onto four wheels, enhancing safety without additional components.
Smart Images
Figure FR2025000190_15052026_PF_FP_ABST
Abstract
Description
DESCRIPTION Title of the invention: Method for controlling a motor vehicle in the event of the vehicle beginning to tip over
[0001] The present invention claims priority from French application 2412242 filed on November 8, 2024, the content of which (text, drawings and claims) is incorporated herein by reference.
[0002] The present invention relates generally to the field of active safety of motor vehicles equipped with a steering wheel having an electric power steering system, also designated by the acronym "EPS" for Electric Power Steering and a dynamic control system of the trajectory and stability of the vehicle, also designated by the Anglo-Saxon acronym "ESP" for "Electronic Stability Program", and relates more particularly to a method of controlling a vehicle in the event of the beginning of the vehicle tipping around its roll axis.
[0003] In certain situations in a vehicle's life, it may begin to tilt around its roll axis when taking a turn at high speed or following a collision with a third vehicle hitting the vehicle from the rear side, or when the driver of the vehicle wants to avoid an obstacle by making a sudden turn of the steering wheel which can cause, at high speed, a swerve with the beginning of the vehicle's overturning or even rollovers.
[0004] The processes implemented to avoid a rollover are essentially preventive and corrective by acting on the selective braking of the wheels, the adjustment of the wheel suspension, ... allowing to counter the force tending to make the vehicle leave its trajectory and potentially leading to a rollover of the vehicle, when thresholds of speed, lateral acceleration or yaw angle exceed determined critical thresholds.
[0005] Such systems monitor the vehicle's dynamic behavior to identify dangerous situations that could cause the vehicle to roll over. They primarily utilize ESP to control speed and maintain vehicle stability.
[0006] However, these methods have their limits and are not always effective, particularly in situations of brutal side collisions resulting in the lifting of both wheels on the same side of the vehicle that suffered the impact.
[0007] The vehicle then becomes momentarily unbalanced, on two wheels (the two wheels aligned on the same side of the vehicle, opposite to the one that was hit) and is therefore likely to tip over and overturn, with potentially serious consequences for the vehicle's passengers and other road users in the immediate vicinity of the hit vehicle.
[0008] The objective of the present invention is to provide a safety solution to this particularly dangerous "extreme" situation, by acting automatically and abruptly on the steering wheel to counter the tipping force and bring the vehicle back onto its four wheels for the ESP to regain control of the vehicle.
[0009] To this end, the invention has as its first object a method of controlling a motor vehicle comprising an electric power steering system, called EPS, and a trajectory and stability control system, called ESP, implementing said method; said method consisting, after detecting a roll angle greater than a first determined threshold, called the critical threshold, corresponding to the beginning of a tipping of the vehicle, of commanding the EPS to apply a steering torque on the steering wheels of the vehicle with a determined steering angle and a determined positive acceleration, then, when the roll angle reaches a second determined threshold, lower than the first threshold, and with a determined negative angular acceleration, of applying a determined counter-steering torque, in a direction opposite to the tipping direction;successive steering and counter-steering pairs allow the vehicle's tipping force to be countered and the ESP to regain control of the vehicle.
[0010] According to one characteristic, the process involves comparing roll angle data obtained by roll angle determination methods, and if the roll angle exceeds a first threshold corresponding to a predetermined maximum roll angle, typically 12°, exceeding the ESP's ability to correct the vehicle, then automatically sending a control signal to an AED control unit, so that the latter applies the steering torque at an angle determined, typically by 15°, in the direction of tipping, with a positive angular acceleration typically of 5 rad / s 2 , on the steering column, or directly on the steering wheels in the absence of a steering column.
[0011] According to another characteristic, the process consists of applying the counter-steering torque in the opposite direction to the tipping, when the roll angle has typically become less than 5°.
[0012] The present invention has as its second object a computer program product comprising instructions which, when the program is executed by a computer, lead the computer to implement the steps of the process as described above.
[0013] The present invention has as its third object a motor vehicle comprising an electric power steering system, called EPS, a trajectory and stability control system, called ESP, and a roll angle estimator or roll angle sensor enabling the roll angle to be determined; said ESP implementing the method as described above.
[0014] The main advantage of the present invention is that it does not require any additional components beyond those already existing on the vehicle, thus enhancing safety without additional cost.
[0015] Other advantages and features of the present invention will become clearer from the following description, given solely by way of non-limiting example and with reference to the drawings in which:
[0016] [Fig. 1] schematically illustrates a first life situation likely to cause the beginning of a tipping of a motor vehicle;
[0017] [Fig. 2] schematically illustrates a second life situation likely to cause the vehicle to begin to tip over;
[0018] [Fig. 3] schematically illustrates the implementation of vehicle control by a control method according to the invention from the beginning of the vehicle's tilting until it is righted; and
[0019] [Fig. 4] illustrates in the form of a flowchart, the main steps of the control process according to the invention.
[0020] The present invention provides a "last resort" solution when state-of-the-art anti-rollover or anti-reverse systems have not been implemented. A measure to prevent the vehicle from beginning to roll over, typically when the roll angle has exceeded a maximum, or "critical," threshold, allowing the vehicle to "right itself" (loss of vehicle control). The beginning of a rollover is concretely manifested by the two wheels on the same side of the vehicle lifting off the ground.
[0021] Figures 1 and 2 schematically illustrate two examples of a life situation of a motor vehicle (VHL) confronted with a collision likely to cause a rollover, or tipping, of the VHL.
[0022] Figure 1 illustrates a first life situation in which the VHL vehicle hits an obstacle on its right, for example, a TPC median strip or a curb or low wall, which can have the effect, at high speed, of lifting the front right of the VHL vehicle and causing a beginning of tipping.
[0023] Figure 2 illustrates a second life situation in which the VHL vehicle is struck on its right rear side by a third vehicle VHT coming from the right.
[0024] Figure 3 schematically represents the implementation of the control method according to the invention applied to a motor vehicle VHL comprising an electric power steering system, or EPS, SDA, and a trajectory control and stabilization system, or ESP, SSV.
[0025] The DAE, SDA, considered in the example embodiment and illustrated in the center of Figure 3, mainly comprises a steering wheel VDD, a steering column CDD, an electric power assist motor MEL, and an electronic control unit UCD, also designated as an ECU (Electronic Control Unit) controlling the assist torque delivered by the motor MEL; torque which is supplied to the steering wheel VDD to turn the steering wheels RDD, RDG of the vehicle VHL via a steering column CDD mechanically linking the steering wheel VDD to the steering wheels RDD, RDG of the vehicle VHL.
[0026] The ESP, SSV, includes at least one computer (ESP computer) which receives information from numerous sensors installed in the vehicle, to allow it to control the trajectory and stability of the vehicle in real time.
[0027] These sensors include:
[0028] - wheel speed sensors, measuring the rotational speed of each of the wheels;
[0029] - a VHL vehicle speed sensor, which calculates the VHL vehicle speed even more accurately than that displayed on the speedometer;
[0030] - a steering wheel angle sensor, located near the front suspension or in the steering column CDD. It allows the ECU, UCD, to know at all times the steering angle ADB of the steering wheels RDD and RDG;
[0031] - a transverse acceleration sensor, which measures the acceleration acting on the VHL vehicle perpendicular to the direction of travel;
[0032] - a yaw rate sensor, which alerts the ESP when the vehicle reaches an abnormal and dangerous threshold; and
[0033] - a CAR rear-wheel roll angle sensor.
[0034] Only the ARV roll angle CAR sensor is shown in Figure 3.
[0035] The ARV roll angle can also be estimated or calculated using various methods, including an estimator that uses information from angular velocity and acceleration sensors, the load transfer rate, the vehicle's AIV tilt angle via an inertial measurement unit, etc.
[0036] The ESP, SSV compares the ARV roll angle data obtained by the ARV roll angle determination means (CAR sensor or estimator). If the ARV roll angle exceeds a threshold corresponding to a determined maximum "critical" roll angle, typically 12°, exceeding the ESP, SSV's ability to correct the vehicle's trajectory, it automatically sends a control signal to the ESD, SDA's control unit (UCD). This signal causes the ESD to apply a sudden and rapid steering torque (CDB) of a determined steering angle (ADB), typically 15°, in the rollover direction, with a positive angular acceleration, typically 5 rad / s². 2, on the steering column CDD, or directly on the steering wheels RDD, RDG if the vehicle VHL is equipped with a "steer-by-wire" type steering system, an anglicism used to designate a steering system without mechanical linkage (without a steering column) between the steering wheel VDD and the steering wheels RDD, RDG of the vehicle VHL.
[0037] The ESP, SSV, sends a control signal to the electric power steering (EPS) system to straighten the steering wheel (VDD) with a determined counter-steering torque (CCB), allowing the vehicle to regain control of the vehicle. vehicle by ESP, SSV, only when it detects that the ARV roll angle has become less than 5° with a negative angular acceleration.
[0038] This maneuver translates into a sudden turn of the steering wheel in the direction of the roll and then in the opposite direction, allowing the roll force to be countered and the ARV roll angle to be brought back below the "critical" threshold, allowing the ESP, SSV, to regain control of the VHL vehicle.
[0039] The process implemented by the ESP, SSV system can be described synthetically by the steps in the flowchart of figure 4.
[0040] The method according to the invention consists, in order to counter the tipping force of the VHL vehicle, after detecting 100 a roll angle ARV greater than a first determined threshold, called the critical threshold, corresponding to a start of tipping of the VHL vehicle, of commanding 200 the electric power steering system SDA of the VHL vehicle so that the latter applies 300 a steering torque CDB on the steering wheels RDD, RDG of the VHL vehicle, with a determined angle ADB and a determined acceleration, in the direction of tipping.
[0041] Then, when the ARV roll angle reaches a second predetermined threshold, lower than the first, with negative angular acceleration, the procedure consists of applying a predetermined countersteering torque (CCB) to the steering wheels (RDD, RDG) in the opposite direction to the roll, enabling the ESP (Electric Vehicle Stability Program). The successive steering and countersteering torques (CDB and CCB) counteract the roll force of the vehicle (VHL) and allow the ESP to regain control of the vehicle (VHL).
[0042] The invention also relates to a computer program product comprising instructions which, when the program is executed by a computer, and in particular by the ESP computer, lead the latter to implement the steps of the process as described above.
Claims
DEMANDS 1. Method of controlling a motor vehicle (MV) comprising an electric power steering (EPS) system and a stability and trajectory control (STC) system, implementing said method; said method consisting, after detecting (100) a roll angle (RA) greater than a first determined threshold, called the critical threshold, corresponding to the beginning of a roll of the vehicle (MV), of commanding (200) the EPS (EPS) to apply (300) a steering torque (ST) on the steering wheels (SWD, STWD) of the vehicle (MV) with a determined steering angle (SWD) and a determined positive acceleration, in the direction of roll of the vehicle (MV) then, when the roll angle (RA) reaches a second determined threshold, less than the first threshold, and with a determined negative angular acceleration, of applying (400) a determined counter-steering torque (CST), in a direction opposite to the direction of roll;the successive steering and counter-steering pairs (CDB, CCB) allowing to counter the tipping force of the vehicle (VHL) and a resumption of control (500) of the vehicle (VHL) by the ESP (SSV).; 2. A method according to the preceding claim, comprising comparing the roll angle (RAV) data obtained by means (CAR) for determining the roll angle (RAV), and if the roll angle (RAV) is greater (100) than a first threshold corresponding to a predetermined maximum roll angle, typically 12°, exceeding the capabilities of the ESP (SSV) to correct the vehicle (VHL), then automatically sending (200) a control signal to a control unit (UCD) of the AED (SDA), so that the latter applies (300) the steering torque (CDB) at a predetermined angle, typically 15°, in the roll direction, with a positive angular acceleration typically of 5 rad / s 2, on the steering column (CDD), or directly on the steering wheels (RDD, RGG) in the absence of a steering column (CDD).
3. A method according to any one of the preceding claims, consisting of applying the countersteering torque (CCB) in the opposite direction to the tipping, when the roll angle (ARV) has typically become less than 5°.
4. Product computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the steps of the process according to any one of claims 1 to 3.
5. Motor vehicle (MV) comprising an electric power steering system, referred to as EPS (Electric Power Steering), a stability and trajectory control system, referred to as ESP (Sterling Vehicle System), and a roll angle estimator (ROI) for determining the roll angle; said ESP (Sterling Vehicle System) implementing the method according to any one of claims 1 to 3.
6. Motor vehicle (MV) comprising an electric power steering system, referred to as EPS (Electric Power Steering), a stability and trajectory control system, referred to as ESP (Sterling and Stability Control), and a roll angle sensor (ROS) for determining the roll angle; said ESP (Sterling and Stability Control) implementing the method according to any one of claims 1 to 3.