FR2924381A3 - Anti-rolling device controlling system for motor vehicle, has electronic control unit for activating and deactivating anti-rolling device based on vehicle operating parameters comprising rolling angles and longitudinal speed of vehicle - Google Patents

Abstract

The system has an electronic control unit (16) for carrying out a test to detect whether an anticipated static rolling angle, a static rolling angle and a dynamic rolling angle of a motor vehicle are respectively greater than maximum thresholds calculated from the corresponding rolling angles. Wheel rotational speed sensors determine longitudinal speed of the vehicle through a determination module. The unit is in the form of a microprocessor, and activates and deactivates an anti-rolling device based on vehicle operating parameters comprising the speed and the angles. An independent claim is also included for a method for controlling an anti-rolling device of a motor vehicle.

Description

The present invention relates to an anti-roll control system and method for a motor vehicle. Conventionally, motor vehicles are provided with a chassis, a passenger compartment, wheels connected to the chassis by a suspension mechanism with front wheels controlled by a steering wheel at the disposal of the driver in the habitable vehicle, and rear wheels, steering or non-steering.

In addition, most motor vehicles are equipped with an anti-roll device, including a semi-active anti-roll device, using the energy of the vehicle without additional energy input. Such anti-roll devices include, for example, anti-roll bars or anti-roll bars, or controlled suspensions. Documents GB 2 377 415, WO 02/008215 and EP 1 022 169 describe anti-roll devices for a motor vehicle controlled according to the speed of the vehicle and the angular position of the steering wheel.

The documents EP 1 541 394 and WO 2005/120190 disclose anti-roll device control systems for a motor vehicle activating or deactivating the anti-roll device as a function of the vehicle speed and lateral acceleration of the vehicle.

US 5,630,623 discloses a control system for a motor vehicle anti-roll device activating or deactivating the anti-roll device according to the vehicle speed, the vehicle lateral acceleration and the angular position of the vehicle. wheel.

Such systems require many sensors and provide the vehicle behavior insufficiently stable at certain demands of the driver on certain road conditions. Certain situations can lead to a loss of control of the vehicle, for example obstacle avoidance. The loss of control in this case is often due to an inadequate response of the vehicle because too bright, not enough amortized or unpredictable. The invention relates to a control system of an anti-roll device for a motor vehicle for improved safety, feeling of safety, comfort and driving pleasure. It is thus proposed a control system of an anti-roll device for a motor vehicle, characterized in that it comprises means for activating and deactivating the anti-roll device as a function of operating parameters of the vehicle comprising the longitudinal speed. of the vehicle, the dynamic roll angle of the vehicle, the static roll angle of the vehicle, and the static roll angle calculated by anticipation of the vehicle. There is also provided a method for controlling a motor vehicle anti-roll device, characterized in that the activation and deactivation of the anti-roll device is controlled according to the operating parameters of the vehicle comprising the longitudinal speed. of the vehicle, the static roll angle calculated by anticipation of the vehicle, the static roll angle of the vehicle, and the dynamic roll angle of the vehicle. The invention allows an increase in the feeling of safety, comfort and driving pleasure.

The present invention will be better understood on studying the detailed description of some embodiments taken by way of non-limiting example and illustrated by the appended drawings, in which: FIG. 1 is a schematic view of a vehicle equipped a control system according to one aspect of the invention; and - Figure 2 is a logic diagram of the system of Figure 1 according to one aspect of the invention.

As can be seen in FIG. 1, the vehicle 1 comprises a chassis 2, two front steering wheels 3 and 4, and two rear wheels 5 and 6, the wheels being connected to the chassis 2 by a suspension mechanism, not shown. The vehicle 1 is completed by a steering system 7 comprising a rack 8 disposed between the front wheels 3 and 4, a rack actuator 9 adapted to orient the front wheels 3 and 4, via the rack 8, in function orders received, mechanically or electrically, from a steering wheel 10 disposed at one end of a steering column 11 connected to the rack actuator 9 at its other end. The vehicle 1 is equipped with an anti-roll device, comprising, in this example, two anti-roll bars 12 and 13 respectively connecting the front wheels 3 and 4 and the rear wheels 5 and 6. The anti-roll device -Roulis comprises at least one actuator, as represented here, two actuators 14 and 15 respectively associated with the front and rear anti-roll bars 13 and 12 capable of acting on said anti-roll bars 12 and 13 to form anti-roll bars. semi-active rolls, upon receipt of a command order from a control unit

The actuators 14 and 15 are capable, for example, of modifying the stiffness of the anti-roll bars 12 and 13 as a function of the setpoint received from the electronic control unit 16.

Of course, alternatively, the invention also applies to any other anti-roll device fitted to a motor vehicle, such as controlled suspensions. The control system comprises one or more sensors 17 for the speed of rotation of the wheels, for example front or rear wheels, making it possible, by means of a determination module 18, to determine the longitudinal speed V of the vehicle 1 , as well as a sensor 19 for measuring the angular position α of the steering wheel 10. The control system of the anti-roll device further comprises a sensor 20 for measuring the lateral acceleration y of the vehicle 1. in addition, the electronic control unit 16 is provided with a calculation module 21 of the lateral acceleration. The electronic control unit 16 may be implemented in the form of a microprocessor equipped with a random access memory, a read-only memory, a central unit, and input / output interfaces for receiving information. sensors or estimators, and to send instructions, in particular to the actuators such as the actuators 14 and 15 of the anti-roll bars 12 and 13. In addition, the control system of the anti-roll device is equipped with a position sensor 23 of the brake pedal, a position sensor 24 of the accelerator pedal, a position sensor 25 of the clutch pedal, and a sensor 26 providing the gear ratio engaged of the gearbox. In addition, the electronic control unit 16 comprises a detection module 28 of an emergency situation in which the driver of the vehicle 1 is located. The electronic control unit 16 also comprises a storage module 29, a module comparison device 30 capable of comparing the value of certain operating parameters of the vehicle with predetermined values, and a time management module 31 able in particular to determine the beginning and the end of time intervals, for example during which are stored the values taken by different operating parameters of the vehicle.

The different thresholds used by the electronic control unit 16 to control the activation or deactivation of the anti-roll device may depend on the longitudinal speed of the vehicle 1. The invention makes it possible to activate the anti-roll device. roll before the excessive rolling of the vehicle to ensure stability, holding and liveliness roll, and disable the anti-roll system when the roll level is below a threshold, so as to improve the motor skills and vehicle maneuverability as well as passenger comfort.

In addition, the deactivation of the anti-roll system can be immediate or delayed. Timing 51 aims to ensure that the vehicle has a sufficiently static, quiet behavior before disabling the anti-roll system.

6 In the case of the delay, it is thus necessary that all roll estimators (static, anticipated static and dynamic) are smaller than the deactivation threshold for a predetermined time for a deactivation request to be generated. This expects the end of the flow of a delay time before deactivating. The time delay may be dependent on the longitudinal speed V of the vehicle 1.

The time delay may also take into account the history of the taxi, or in other words, data stored during a previous time interval, to identify particular types of driving, or particular routes, such as mountain roads. These data stored in the storage module 29, while using the time management module 31, allow the electronic control unit 16 to calculate a weighting coefficient P, between 0 and 1, of the maximum disconnection delay Tempo_max. anti-roll device.

Thus, the actual delay is equal to [3 * Tempo_max. This weighting coefficient may therefore reflect the type of course, such as a course on motorway or mountain road, as well as the type of conduct related to the demands of the driver on the steering column 11, the brake pedal and the accelerator pedal. The time delay can still be set when the vehicle is in focus. FIG. 2 illustrates the operation of a control system of an anti-roll device of FIG. 1.

The electronic control unit 16 performs a test 35 to detect whether the anticipated static roll angle OSA (or anticipated static roll) of the vehicle 1 is greater than a calculated maximum threshold of the expected static roll angle eSA_calc_max ( condition 37), or if the static roll angle es of the vehicle 1 is greater than a calculated maximum threshold of the static roll angle es_calc_max (condition 36), or if the dynamic roll angle e of the vehicle 1 is greater than at a calculated maximum threshold of the dynamic roll angle ecalc_max (condition 41). The maximum OSA thresholds maximum max and max ecalc are the activation thresholds of the anti-roll system. The static roll angle is determined by the following relationship (R1) OS = G8 * y (R1) Os is the static roll angle [rad], Ge the specific roll [rad / (m / s2)], y the measured lateral acceleration of the vehicle [m / s2].

In addition, the measurement of the flying angle α is in advance of phase on the lateral acceleration undergone by the vehicle. By measuring the flying angle α, it is therefore possible to estimate in advance the lateral acceleration of the vehicle using a model of the lateral dynamics of the vehicle. For example, it is possible to use the Ackerman-DA model to estimate the lateral acceleration of the vehicle knowing the steering angle, the speed of the vehicle, the wheelbase, the reduction factor between the steering angle and the angle of the wheels, and the 8 angular dynamics. This model can be implemented in the calculation module 21. The anticipated static roll angle OSA is thus determined by the following relation (R2), corresponding to the product of the specific roll by the estimated lateral acceleration of the vehicle: OSA Dem ( V2 * da + L) (R2) Ge * V2 * a 8SA is the anticipated static roll angle [rad], 10 Ge is the specific roll [rad / (m / s2)], V is the longitudinal velocity of the vehicle [m / s], a is the measured angle of the flywheel, Dem the reduction factor between the steering angle and the wheel angle, 15 L the wheelbase [m], of the angular momentum [s2 / m].

As can be noted, only measurements of the steering angle α with dedicated sensors and estimation of the longitudinal velocity V of the vehicle (the velocity V is calculated in the determination module 18 from the measurements made of the one or more sensor (s) 17 of the wheel rotation speed) are performed, the other data being either geometric data related to the type of vehicle, or data identified by prior tests. In practice, it will be possible to set the value of the angular dynamic da to a value identified under conditions of strong adhesion of the vehicle, because it is the most restrictive condition. It is however quite possible to vary in real time this parameter depending on the effective adhesion of the vehicle. In this case, a road adherence estimator 22 must be included in the strategy. To take account of the transient regime, it is planned to model the dynamic rolling of the vehicle by estimating the evolution of the rolling speed by the following relation (R3): 2 S * Ge * wn 52 + 2 * * (on * S + con (R3) 0 Y 10 0 is the roll speed [rad / s] y the measured vehicle lateral acceleration [m / s2], Ge the static specific roll [rad / m / s2)], con own pulse [rad / s], the damping coefficient of the model. The lateral acceleration of the vehicle is measured. The static specific roll, the proper pulsation, and the damping coefficient of the model are known by conventional tests in the automobile environment (cornering, sinewheeling, etc.). The test 35 also detects whether the longitudinal speed V of the vehicle 1 is greater than a maximum speed threshold S_V_max (condition 39), from which the vehicle is considered to be traveling at a very high speed. The electronic control unit 16 detects an emergency situation of the vehicle 1 by a test 38 testing whether the position of the brake pedal pos_pf is greater than a maximum threshold of position of the brake pedal S_pos_pf_max (condition 42), or if the position of the accelerator pedal is greater than a maximum threshold of position of the accelerator pedal S_pos_pa_max (condition 42). When one of the conditions 36, 37, 38, 39, 41 or is realized, and detected during the test 35, the electronic control unit 16 controls the activation of the antiroll device by means of the actuators 14 and 15. If none of these conditions 36, 37, 38, 39 or 41 is achieved, the electronic control unit 16 also tests (test 44) if the longitudinal speed V of the vehicle 1 is below a minimum speed threshold S_V_min ( condition 45) or else (test 46) if a plurality of conditions are realized (test 47). The minimum speed threshold corresponds to a stopping situation of the vehicle or similar to stopping the vehicle (very low speed).

The test 47 consists in verifying the realization of a set of conditions comprising the expected OSA static roll angle less than a calculated minimum threshold of the expected static roll angle eSA_calc_min (condition 49), if the static roll angle OS is below a calculated minimum threshold of the static roll angle eS_calc_min (step 48), if the dynamic roll angle e is less than a calculated minimum threshold of the dynamic roll angle ecalc_min of the vehicle (condition 50) . The minimum thresholds OSA calc min, OS calc min, and ecalc min correspond to deactivation thresholds of the anti-roll system. After the test 47, a delay can be carried out to ensure the stable state of the vehicle. Thus, when the test 44 is performed, the electronic control unit 16 controls the deactivation of the anti-roll device by means of the actuators 14 and 15.

11 Each deactivation threshold can be calculated from the corresponding activation threshold by a relation (R4) of the type: deactivation threshold = activation threshold - offset (R4)

All minimum and maximum roll angle thresholds, ie the thresholds for deactivation and activation of the anti-roll system, may depend on the speed V of the vehicle (1). In this case, these thresholds are established from a map (speed, threshold activation / deactivation) established during the development of the vehicle. More precisely, the strictly positive offset of the relation (R4) will then depend on the speed V of the vehicle.

The invention provides a control law which drives the semi-active anti-roll device so as to provide an improved feeling of safety and driving comfort. The invention makes it possible to adopt the most stable behavior possible whatever the driver's demands and the state of the roadway, and offers a very high level of safety and improved driving comfort.

Claims (16)

1. Control system of an anti-roll device (12, 13) for a motor vehicle (1), characterized in that it comprises means for activating and deactivating (16) the anti-roll device according to parameters. vehicle operating system (1) comprising the longitudinal speed (V) of the vehicle (1), the dynamic roll angle (8) of the vehicle, the static roll angle (8S) of the vehicle, and the anticipated static roll (8SA) of the vehicle. 2. The system of claim 1, wherein said operating parameters of the vehicle (1) further comprise the position of the brake pedal (pos_pf), and / or the position of the accelerator pedal (pos_pa), and / or the speed (V) of the vehicle, and / or the position of the clutch pedal, and / or the gear reduction ratio engaged of the gearbox. 3. System according to one of the preceding claims, comprising means (20) for measuring the lateral acceleration (y) of the vehicle (1), and wherein said activation and deactivation means (16) are adapted to activate. said anti-roll device when the static roll angle (8S) of the vehicle is greater than a calculated maximum threshold of the static roll angle (8S_calc__max) 4. System according to one of the preceding claims, wherein, the system comprising means (21) for measuring the speed (V) of the vehicle (1) and the angle (a) of the vehicle steering wheel, said means activation and deactivation means (16) are adapted to activate the anti-roll device when the anticipated vehicle static roll angle (OSA) is greater than a calculated maximum static roll angle threshold (OSA_calc_max) • 5. System according to claim 4, characterized in that the predeterminable static roll angle (OSA) is connected to the speed (V) of the vehicle (1) and the angle (a) of the flying G * 2. vehicle by the relationship OSA = De ~ VZ * daa L) in which Dem is the gear ratio between the steering angle and the wheel angle, L the vehicle wheelbase, and the angular dynamics of the vehicle. 6. System according to one of the preceding claims, wherein said activation and deactivation means (16) are adapted to activate said anti-roll device when the dynamic roll angle (0) of the vehicle is greater than a maximum threshold. calculated dynamic roll angle (e_calc__max) 7. System according to claim 6, characterized in that the dynamic rolling angle e is estimated from a model expressed by the relation 6 = s * Ge * wn in y s + 2 * * wn * s + wn which O is the roll speed, y is the measured lateral acceleration of the vehicle, Ge the static specific roll, wn the proper pulsation, and the damping coefficient of the model. 8. System according to one of the preceding claims, wherein said activation and deactivation means (16) are adapted to activate the anti-roll device when the longitudinal speed (V) of the vehicle (1) is greater than a maximum speed threshold. (S_V_max). 9. System according to one of the preceding claims, wherein said activation and deactivation means (16) are adapted to activate the anti-roll device when an emergency situation (38) is detected by detection means (28). according to vehicle operating parameters (1) including the position (pos_pf) of the brake pedal, and / or the position of the accelerator pedal (pos_pa), and / or the gear ratio engaged of the gearbox speeds. 10. System according to claim 9, wherein said detection means (28) are adapted to detect an emergency situation when the position of the brake pedal (pos_pf) is greater than a maximum threshold of position of the brake pedal (S_pos_pf_max), and / or the position of the accelerator pedal (pos_pa) is greater than a maximum threshold of position of the accelerator pedal (S_pos_pa_max). 11. System according to one of the preceding claims, wherein said activation and deactivation means (16) are adapted to disable the anti-roll device (12, 13) when the activation conditions of the anti-roll device are not not met, and that the longitudinal velocity (V) of the vehicle (1) is less than a minimum speed threshold (S_V_min) or that a plurality of conditions are realized, said plurality of conditions including the static roll angle calculated by anticipation (OSA) of the vehicle (1) less than a calculated minimum threshold of anticipated static roll angle (OSA_calc_min), and / or the static roll angle (OS) of the vehicle below a calculated minimum threshold of the angle of static roll (OS_calc_min), and / or the dynamic roll angle (6) lower than a calculated minimum threshold of the dynamic roll angle (6calc_min) • The system of claim 11, wherein said plurality of conditions further comprises the termination of the flow of a deactivation delay time. 13. The system of claim 12, wherein the delay time depends on the speed V of the vehicle (1), or depends on the rolling history of the vehicle or is set during the development of the vehicle. 14. System according to one of claims 11 to 13, characterized in that the maximum / activation thresholds of the anti-roll device (12, 13) and the minimum / deactivation thresholds of the anti-roll device (12, 13). ) are linked by the relation: deactivation threshold = activation threshold -decrease 15. System according to claim 14, characterized in that the offset, strictly positive, depends on the speed (V) of the vehicle (1). 20 16. A method of controlling an anti-roll device (12, 13) of a motor vehicle (1), characterized in that it controls the activation and deactivation of the anti-roll device according to the operating parameters of the vehicle ( 1) comprising the longitudinal velocity (V) of the vehicle (1), the calculated vehicle anticipated static roll angle (1), the static roll angle of the vehicle (1), and the dynamic roll angle. of the vehicle (1). 15