WO2007085751A1 - Method for reducing the braking distance of a motor vehicle and device for implementing it - Google Patents
Method for reducing the braking distance of a motor vehicle and device for implementing it Download PDFInfo
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- WO2007085751A1 WO2007085751A1 PCT/FR2007/050604 FR2007050604W WO2007085751A1 WO 2007085751 A1 WO2007085751 A1 WO 2007085751A1 FR 2007050604 W FR2007050604 W FR 2007050604W WO 2007085751 A1 WO2007085751 A1 WO 2007085751A1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D9/00—Steering deflectable wheels not otherwise provided for
- B62D9/007—Emergency systems using the steering system for braking
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D59/00—Plugs, sleeves, caps, or like rigid or semi-rigid elements for protecting parts of articles or for bundling articles, e.g. protectors for screw-threads, end caps for tubes or for bundling rod-shaped articles
- B65D59/04—Sleeves, e.g. postal tubes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2260/00—Interaction of vehicle brake system with other systems
- B60T2260/06—Active Suspension System
Definitions
- a method of reducing the braking distance of a motor vehicle and a device for carrying it out is a method of reducing the braking distance of a motor vehicle and a device for carrying it out.
- the invention relates to a method for actively reducing the braking distance of a motor vehicle by simultaneous action on the gripper and the camber of the front wheels while driving. It also relates to a device for implementing said method.
- the invention proposes a method of simultaneous action on the gripper and the camber of the front wheels according to the driving conditions of the vehicle, in particular the adhesion .
- a first object of the invention is a method of actively reducing the braking distance of a motor vehicle equipped with at least two steered wheels and a driving assistance system, characterized in that , in case of detection of an emergency situation requiring maximum braking from information from the driver on the one hand and related to the vehicle environment on the other hand, followed by an application of the effort maximum braking on the steered wheels performed by the assisted driver of the driving assistance system, it includes a step of correcting angles of the steering wheel planes, by simultaneously applying clamping instructions and camber on the wheels to obtain the maximum longitudinal forces delivered by the tires and causing the maximum deceleration of the vehicle.
- the method for the tire of each of the steered wheels, it determines ⁇ and camber set points ⁇ which make the total longitudinal force, generated by the drift due to the pliers and the camber, and delivered by said tire in the direction of movement of the vehicle in the opposite direction to cause the deceleration of the vehicle, these instructions being chosen from the values established by mapping according to the type of tire and adhesion, knowing that the rigidity of the tire derives from it, the rigidity of the tire in camber, the maximum longitudinal and lateral forces, delivered by the tire, are fixed data.
- a second object of the invention is a device for implementing the control method, characterized in that it is embedded in the vehicle and comprises an electronic computer which receives information on the driver and the environment of the vehicle, which determines the optimum values of the gripper and the camber of each wheel and which controls at least one actuator per wheel to control the angles of clamp and camber.
- FIG. 1 a schematic view from above of the position of the wheels of a front axle of a motor vehicle in a straight line;
- FIG. 2 the different forces delivered by a motor vehicle tire under braking;
- FIGS. 4a and 4b two variants of application of the device for implementing the method in a wheel plane defined by its three attachment points, according to the invention.
- the method of reducing the braking distance of a motor vehicle equipped with at least two steering wheels and a driving assistance system, comprises three main stages, including a first step of detection of an emergency situation requiring maximum braking, based on information from the driver on the one hand and related to the environment of the vehicle on the other hand.
- the data coming from the driver is for example the driving speed or the force exerted on the brake pedal, the time of passage between the accelerator and brake pedals, the activation of the brake assist system.
- AFU emergency is for example the driving speed or the force exerted on the brake pedal, the time of passage between the accelerator and brake pedals, the activation of the brake assist system.
- the environmental data include the distance between the vehicle and the detected obstacle, the speed of approach, the grip of the tires on the road, the time before impact, and come for example from the brake assist system as than ABS - Anti Blocking System - via the brake pedal lifts when the regulation is triggered.
- a second step of application of the maximum braking force on the front wheels is performed by the driver and the emergency braking system, followed by a third step of correcting the angles of the front wheel planes, by application of clamping and cambering instructions on the front wheels, these instructions being determined to obtain the maximum longitudinal force generated by the tires and causing the maximum deceleration of the vehicle.
- This correction of the angles of the planes of the steering wheels is achieved by the control of one or more actuators.
- the gripper is the angle that the wheel plane makes with respect to the longitudinal axis OX of the vehicle in the plane XOY.
- the camber is the angle that the wheel plane makes with respect to the vertical axis OZ of the vehicle in the plane YOZ.
- the tire delivers from one part a longitudinal force F x along the axis OX, in the plane parallel to the road in the opposite direction to the displacement of the vehicle and a transverse or lateral force F ⁇ ⁇ , generated by the drift known by the value of the clamp ⁇ along the axis OY perpendicular to the axis OX and in the plane parallel to the road, the resultant of which is the total effort F generated by the tire without camber, and secondly a lateral force F ⁇ ⁇ generated by the camber ⁇ of the wheels of the train.
- the direction of the vehicle speed vector is referenced V v .
- the vehicle is generally equipped with an ESP - Electronic Stability Program - and actuators acting on the tensor of the tire, or tires that can be fitted with transponders, the following data are considered to be known:
- the rigidity of the drifting tire D the rigidity of the tire in camber P
- the maximum longitudinal force F Xmax delivered by the tire along the axis OX of the OXYZ mark in the plane of the wheel in the direction of movement of the tire
- vehicle the maximum transverse force F Ymax delivered by the tire along the axis OY OXYZ mark in the plane of the wheel and perpendicular to the axis OX.
- the invention consists in determining the values of the clamp ⁇ and the camber ⁇ to obtain the maximum value of this longitudinal force, knowing that the rigidity of the tire D derives from it, the rigidity of the tire P in camber, the maximum longitudinal forces F Xmax and lateral F Ymax , delivered by the tire, are known and fixed data.
- These optimum values of the clamp ⁇ and camber ⁇ are chosen from the values established by mapping according to the type of tire and adhesion, knowing that the more one generates camber thrust, the more the wheel train must be pinched.
- These optimum values of clamp ⁇ and camber ⁇ serve as instructions for controlling the angles of the front wheel planes.
- This method of reducing the braking distance is implemented by a device embedded on the vehicle and comprising in particular one or more actuators controlled by an electronic computer, either dedicated to the method itself or belonging to the help system. driving for the control of braking or anti-slip wheels for example.
- This electronic computer receives information about the driver and the environment of the vehicle, and simultaneously determines the optimum values of the clamp and the camber of each wheel.
- the device used on a conventional vehicle, with rack-and-pinion steering, or "Steer-By-Wire" type with linked wheels or with a conventional steering column comprises a wheel actuator for simultaneously controlling the angles. of clamp and camber imposed.
- FIG. 4a shows on the one hand the pivot axis ⁇ c of the wheel for the camber and, on the other hand, the pivot axis ⁇ B of the wheel for turning in normal mode, ie in conventional steering, which intersect perpendicularly to the point of attachment P M of the hub, and the wheel plane is then defined by its three attachment points, the point of attachment P B of the steering rod, the point of attachment P M of hub and that P A of the actuator.
- the application point P A of the camber actuator controlled according to the method of the invention is placed on an axis ⁇ A of the wheel, which makes an angle v with the pivot axis ⁇ B of the wheel for the steering, defined to obtain the camber effect ⁇ induced during the steering.
- the angles v and p are defined by the implantation of the actuators.
- the device for implementing the method on a motor vehicle equipped with a decoupled left-right steering "Steer-By-Wire" type steering which already comprises an actuator dedicated to driving the gripper, further includes an actuator dedicated to driving the camber to decouple the two degrees of freedom.
- FIG. 4b shows on the one hand the pivot axis ⁇ c of the wheel for the camber and, on the other hand, the pivot axis ⁇ B of the wheel for the deflection in the normal mode on which the point is located.
- the stopping distance of a motor vehicle, during braking in a straight line is substantially reduced by increasing the longitudinal forces delivered by the tires of the steering wheels obtained by simultaneous action on the clamp and the wheel camber.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transportation (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Vehicle Body Suspensions (AREA)
- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
Abstract
The invention relates to a method for actively reducing the braking distance of a motor vehicle fitted with at least two steered wheels and a driving assistance system, characterized in that, if an emergency situation requiring maximum braking is detected from information originating from the driver on the one hand, and associated with the environment of the vehicle on the other hand, followed by application of maximum braking force to the steered wheels performed by the driver assisted by the driving assistance system, it comprises a step of correcting the angles of the planes of the steered wheels by simultaneously applying toe-in (d) and camber (ß) setpoint values to the wheels in order to obtain the maximum longitudinal forces delivered by the tyres and causing maximum deceleration of the vehicle. It also relates to a device for implementing it.
Description
Procédé de réduction de la distance de freinage d'un véhicule automobile et dispositif de mise en oeuvre. A method of reducing the braking distance of a motor vehicle and a device for carrying it out.
L'invention concerne un procédé de réduction active de la distance de freinage d'un véhicule automobile par action simultanée sur la pince et le carrossage des roues avant pendant le roulage. Il concerne également un dispositif de mise en œuvre dudit procédé.The invention relates to a method for actively reducing the braking distance of a motor vehicle by simultaneous action on the gripper and the camber of the front wheels while driving. It also relates to a device for implementing said method.
Actuellement, les gains potentiels sur la réduction de la distance d'arrêt d'un véhicule automobile en ligne droite sont limités par le potentiel du pneu en transmission d'effort longitudinal. C'est pourquoi une solution existante pour réduire la distance d'arrêt consiste à utiliser d'autres propriétés du pneu, en particulier à faire travailler le pneu avec un minimum de pince et de carrossage des roues, les valeurs étant prédéfinies par cartographie pour chaque type de pneu. Ainsi, les efforts longitudinaux délivrés par le pneu sont a priori optimaux pour freiner en ligne droite sur une distance minimale, mais leur réglage par cartographie empêche toute adaptation aux conditions de roulage.Currently, the potential gains in reducing the stopping distance of a motor vehicle in a straight line are limited by the potential of the tire in longitudinal transmission of effort. That is why an existing solution to reduce the stopping distance is to use other properties of the tire, in particular to make the tire work with a minimum of clamp and camber wheels, the values being predefined by mapping for each type of tire. Thus, the longitudinal forces delivered by the tire are a priori optimal for braking in a straight line over a minimum distance, but their setting by mapping prevents any adaptation to the driving conditions.
Pour réduire encore la distance de freinage en augmentant les efforts longitudinaux du pneu, l'invention propose un procédé d'action simultanée sur la pince et le carrossage des roues avant directrices en fonction des conditions de roulage du véhicule, en particulier de l'adhérence.To further reduce the braking distance by increasing the longitudinal forces of the tire, the invention proposes a method of simultaneous action on the gripper and the camber of the front wheels according to the driving conditions of the vehicle, in particular the adhesion .
Pour cela, un premier objet de l'invention est un procédé de réduction active de la distance de freinage d'un véhicule automobile équipé d'au moins deux roues directrices et d'un système d'aide à la conduite, caractérisé en ce que, en cas de détection d'une situation d'urgence nécessitant un freinage maximal à partir d'informations venant du conducteur d'une part et liées à l'environnement du véhicule d'autre part, suivie d'une application de l'effort maximal de freinage sur les roues directrices effectuée par le conducteur assisté du système d'aide à la conduite, il comprend une étape de correction des angles des plans de roues directrices, par application simultanée de consignes de pince et de carrossage sur les roues pour obtenir les efforts longitudinaux maximaux délivrés par les pneus et provoquant la décélération maximale du véhicule.For this, a first object of the invention is a method of actively reducing the braking distance of a motor vehicle equipped with at least two steered wheels and a driving assistance system, characterized in that , in case of detection of an emergency situation requiring maximum braking from information from the driver on the one hand and related to the vehicle environment on the other hand, followed by an application of the effort maximum braking on the steered wheels performed by the assisted driver of the driving assistance system, it includes a step of correcting angles of the steering wheel planes, by simultaneously applying clamping instructions and camber on the wheels to obtain the maximum longitudinal forces delivered by the tires and causing the maximum deceleration of the vehicle.
Selon une caractéristique du procédé, pour le pneu de chacune des roues directrices, il détermine des consignes de pince δ et de carrossage β qui rendent
maximal l'effort longitudinal total, généré par la dérive due à la pince et au carrossage, et délivré par ledit pneu dans la direction de déplacement du véhicule en sens inverse pour provoquer la décélération du véhicule, ces consignes étant choisies parmi les valeurs établies par cartographie en fonction du type de pneu et de l'adhérence, sachant que la rigidité du pneu en dérive, la rigidité du pneu en carrossage, les efforts maximaux longitudinal et latéral, délivrés par le pneu, sont des données fixées.According to one characteristic of the method, for the tire of each of the steered wheels, it determines β and camber set points β which make the total longitudinal force, generated by the drift due to the pliers and the camber, and delivered by said tire in the direction of movement of the vehicle in the opposite direction to cause the deceleration of the vehicle, these instructions being chosen from the values established by mapping according to the type of tire and adhesion, knowing that the rigidity of the tire derives from it, the rigidity of the tire in camber, the maximum longitudinal and lateral forces, delivered by the tire, are fixed data.
Un second objet de l'invention est un dispositif de mise en œuvre du procédé de contrôle, caractérisé en ce qu'il est embarqué sur le véhicule et comprend un calculateur électronique qui reçoit des informations sur le conducteur et sur l'environnement du véhicule, qui détermine les valeurs optimales de la pince et du carrossage de chaque roue et qui commande au moins un actionneur par roue pour piloter les angles de pince et de carrossage.A second object of the invention is a device for implementing the control method, characterized in that it is embedded in the vehicle and comprises an electronic computer which receives information on the driver and the environment of the vehicle, which determines the optimum values of the gripper and the camber of each wheel and which controls at least one actuator per wheel to control the angles of clamp and camber.
D'autres caractéristiques et avantages de l'invention apparaîtront à la lecture de la description concernant un véhicule automobile à quatre roues, illustrée par les figures suivantes qui sont :Other features and advantages of the invention will appear on reading the description relating to a motor vehicle with four wheels, illustrated by the following figures which are:
- la figure 1 : une vue schématique de dessus de la position des roues d'un train avant de véhicule automobile en ligne droite ; - la figure 2 : les différents efforts délivrés par un pneu de véhicule automobile en freinage ;- Figure 1: a schematic view from above of the position of the wheels of a front axle of a motor vehicle in a straight line; - Figure 2: the different forces delivered by a motor vehicle tire under braking;
- la figure 3 : la représentation d'une ellipse d'adhérence d'un pneu ;- Figure 3: the representation of an adhesion ellipse of a tire;
- les figures 4a et 4b : deux variantes d'application du dispositif de mise en œuvre du procédé dans un plan de roue défini par ses trois points de fixation, selon l'invention.FIGS. 4a and 4b: two variants of application of the device for implementing the method in a wheel plane defined by its three attachment points, according to the invention.
Selon l'invention, le procédé de réduction de la distance de freinage d'un véhicule automobile, équipé d'au moins deux roues directrices et d'un système d'aide à la conduite, comporte trois étapes principales, dont une première étape de détection d'une situation d'urgence nécessitant un freinage maximal, à partir d'informations venant du conducteur d'une part et liées à l'environnement du véhicule d'autre part. Les données provenant du conducteur sont par exemple la vitesse d'enfoncement ou l'effort exercé sur la pédale de frein, le temps de passage entre les pédales d'accélérateur et de frein, l'activation du système d'assistance au freinage d'urgence AFU. Les données sur l'environnement sont notamment la distance entre le véhicule et l'obstacle détecté, la vitesse de rapprochement, l'adhérence des pneus sur la route, le temps avant impact, et proviennent par exemple du système d'aide au freinage tel que
l'ABS - Anti Blocking System - par l'intermédiaire des remontées de pédale de frein quand la régulation est déclenchée. Une deuxième étape d'application de l'effort maximal de freinage sur les roues avant est effectuée par le conducteur et le système de freinage d'urgence, suivie d'une troisième étape de correction des angles des plans de roues avant, par application de consignes de pince et de carrossage sur les roues avant, ces consignes étant déterminées pour obtenir l'effort longitudinal maximal généré par les pneus et provoquant la décélération maximale du véhicule. Cette correction des angles des plans des roues directrices est réalisée par la commande d'un ou de plusieurs actionneurs.According to the invention, the method of reducing the braking distance of a motor vehicle, equipped with at least two steering wheels and a driving assistance system, comprises three main stages, including a first step of detection of an emergency situation requiring maximum braking, based on information from the driver on the one hand and related to the environment of the vehicle on the other hand. The data coming from the driver is for example the driving speed or the force exerted on the brake pedal, the time of passage between the accelerator and brake pedals, the activation of the brake assist system. AFU emergency. The environmental data include the distance between the vehicle and the detected obstacle, the speed of approach, the grip of the tires on the road, the time before impact, and come for example from the brake assist system as than ABS - Anti Blocking System - via the brake pedal lifts when the regulation is triggered. A second step of application of the maximum braking force on the front wheels is performed by the driver and the emergency braking system, followed by a third step of correcting the angles of the front wheel planes, by application of clamping and cambering instructions on the front wheels, these instructions being determined to obtain the maximum longitudinal force generated by the tires and causing the maximum deceleration of the vehicle. This correction of the angles of the planes of the steering wheels is achieved by the control of one or more actuators.
La pince est l'angle que fait le plan de roue par rapport à l'axe longitudinal OX du véhicule dans le plan XOY. Le carrossage est l'angle que fait le plan de roue par rapport à l'axe vertical OZ du véhicule dans le plan YOZ.The gripper is the angle that the wheel plane makes with respect to the longitudinal axis OX of the vehicle in the plane XOY. The camber is the angle that the wheel plane makes with respect to the vertical axis OZ of the vehicle in the plane YOZ.
En considérant le repère orthonormé OXYZ attaché au centre du pneu, comme le montrent les figurel et 2, dont la première est une vue schématique de dessus de la position des roues d'un train avant de véhicule en ligne droite, le pneu délivre d'une part un effort longitudinal Fx selon l'axe OX, dans le plan parallèle à la route dans le sens opposé au déplacement du véhicule et un effort transversal ou latéral Fδ γ , généré par la dérive connue par la valeur de la pince δ, selon l'axe OY perpendiculaire à l'axe OX et dans le plan parallèle à la route, dont la résultante est l'effort F total généré par le pneu sans carrossage, et d'autre part un effort latéral Fβ γ généré par le carrossage β des roues du train. La direction du vecteur vitesse du véhicule est référencée Vv.By considering the orthonormal mark OXYZ attached to the center of the tire, as shown by the figures and 2, the first of which is a schematic view from above of the position of the wheels of a vehicle front train in a straight line, the tire delivers from one part a longitudinal force F x along the axis OX, in the plane parallel to the road in the opposite direction to the displacement of the vehicle and a transverse or lateral force F δ γ , generated by the drift known by the value of the clamp δ along the axis OY perpendicular to the axis OX and in the plane parallel to the road, the resultant of which is the total effort F generated by the tire without camber, and secondly a lateral force F β γ generated by the camber β of the wheels of the train. The direction of the vehicle speed vector is referenced V v .
L'effort transversal ou latéral Fδ γ généré par la dérive D est donné par l'équationThe transverse or lateral force F δ γ generated by the drift D is given by the equation
E1 suivante :E1 following:
(E1) fδ γ = -D x δ(E1) f δ γ = -D x δ
Et l'effort latéral Fβ γ généré par le carrossage β des roues est donné par l'équation E2 suivante :And the lateral force F β γ generated by the camber β of the wheels is given by the following equation E2:
(E2) fβ y = -P χ β(E2) f β y = -P χ β
Le véhicule étant équipé généralement d'un système de contrôle de la trajectoire ESP - Electronic Stability Program - et d'actionneurs agissant sur le tenseur
du pneu, ou les pneus pouvant être dotés de transpondeurs, les données suivantes sont considérées comme connues :The vehicle is generally equipped with an ESP - Electronic Stability Program - and actuators acting on the tensor of the tire, or tires that can be fitted with transponders, the following data are considered to be known:
- la rigidité du pneu en dérive D, la rigidité du pneu en carrossage P, - l'effort longitudinal maximal FXmax délivré par le pneu selon l'axe OX du repère OXYZ, dans le plan de la roue suivant la direction de déplacement du véhicule, l'effort transversal maximal FYmax délivré par le pneu selon l'axe OY du repère OXYZ dans le plan de la roue et perpendiculaire à l'axe OX.the rigidity of the drifting tire D, the rigidity of the tire in camber P, the maximum longitudinal force F Xmax delivered by the tire along the axis OX of the OXYZ mark, in the plane of the wheel in the direction of movement of the tire; vehicle, the maximum transverse force F Ymax delivered by the tire along the axis OY OXYZ mark in the plane of the wheel and perpendicular to the axis OX.
Ces efforts longitudinal FXmax et latéral FYmax maximaux délivrés par le pneu, sont généralement estimés par des capteurs associés au système ESP par exemple.These longitudinal forces F Xmax and lateral maximum F Ymax delivered by the tire, are generally estimated by sensors associated with ESP system for example.
Les potentiels d'accélération et de freinage du véhicule sont différents selon les conditions d'adhérence des pneus sur la route et les efforts longitudinaux et latéraux disponibles sur un pneu sont donnés par l'équation E3 suivante à partir de l'ellipse d'adhérence représentée sur la figure 3 :The acceleration and braking potentials of the vehicle are different depending on the adhesion conditions of the tires on the road and the longitudinal and lateral forces available on a tire are given by the following equation E3 from the grip ellipse represented in FIG. 3:
Ainsi, l'effort longitudinal Fx restant disponible, est donc défini par l'équation E4 suivante :Thus, the longitudinal force F x remaining available, is therefore defined by the following equation E4:
(E4) Fx
de sorte que l'effort total F délivré par le pneu sans carrossage est donné par l'équation E5 suivante :(E4) Fx so that the total force F delivered by the tire without camber is given by the following equation E5:
(E5) F = J 'F2 X + F δ2(E5) F = F 'F 2 X + F δ 2
YY
Et l'effort longitudinal total F|0ng généré par le pneu avec dérive et carrossage, dans la direction du déplacement du véhicule et en sens inverse et qui provoque la décélération du véhicule, est la somme de la poussée de carrossage projetée longitudinalement et de l'effort précédemment calculé, également projeté longitudinalement. Il est donné par l'équation E6 suivante :
Flong = Fβ γ x ûn δ + F x cos(<? - θ) = -P x β x sin δ +
- β)And the total longitudinal force F | 0ng generated by the tire with drift and camber, in the direction of movement of the vehicle and in reverse and which causes the deceleration of the vehicle, is the sum of the camber thrust projected longitudinally and the effort previously calculated, also projected longitudinally . It is given by the following equation E6: Flong = F β γ x ûn δ + F x cos (<? - θ) = -P x β x sin δ + - β)
L'invention consiste à déterminer les valeurs de la pince δ et du carrossage β pour obtenir la valeur maximale de cet effort longitudinal, sachant que la rigidité du pneu D en dérive, la rigidité du pneu P en carrossage, les efforts maximaux longitudinal FXmax et latéral FYmax, délivrés par le pneu, sont des données connues et fixées. Ces valeurs optimales de la pince δ et du carrossage β sont choisies parmi les valeurs établies par cartographie en fonction du type de pneu et de l'adhérence, sachant que plus on génère de poussée de carrossage, plus le train des roues doit être pincé. Ces valeurs optimales de pince δ et de carrossage β servent de consignes pour la commande des angles des plans de roues avant directrices.The invention consists in determining the values of the clamp δ and the camber β to obtain the maximum value of this longitudinal force, knowing that the rigidity of the tire D derives from it, the rigidity of the tire P in camber, the maximum longitudinal forces F Xmax and lateral F Ymax , delivered by the tire, are known and fixed data. These optimum values of the clamp δ and camber β are chosen from the values established by mapping according to the type of tire and adhesion, knowing that the more one generates camber thrust, the more the wheel train must be pinched. These optimum values of clamp δ and camber β serve as instructions for controlling the angles of the front wheel planes.
Ce procédé de réduction de la distance de freinage est mis en œuvre par un dispositif embarqué sur le véhicule et composé notamment d'un ou plusieurs actionneurs pilotés par un calculateur électronique, soit dédié au procédé lui-même, soit appartenant au système d'aide à la conduite pour le contrôle du freinage ou de l'anti-patinage des roues par exemple. Ce calculateur électronique reçoit des informations sur le conducteur et sur l'environnement du véhicule, et détermine simultanément les valeurs optimales de la pince et du carrossage de chaque roue.This method of reducing the braking distance is implemented by a device embedded on the vehicle and comprising in particular one or more actuators controlled by an electronic computer, either dedicated to the method itself or belonging to the help system. driving for the control of braking or anti-slip wheels for example. This electronic computer receives information about the driver and the environment of the vehicle, and simultaneously determines the optimum values of the clamp and the camber of each wheel.
Selon une première variante, le dispositif mis en œuvre sur un véhicule classique, avec direction à crémaillère, ou de type « Steer-By-Wire » à roues liées ou avec colonne de direction classique, comporte un actionneur par roue pour piloter simultanément les angles de pince et de carrossage imposés. Sur la figure 4a sont représentés d'une part l'axe Δc de pivot de la roue pour le carrossage et d'autre part l'axe de pivot ΔB de la roue pour le braquage en mode normal, soit en braquage classique, qui se coupent perpendiculairement au point d'attache PM du moyeu, et le plan de roue est alors défini par ses trois points de fixation, le point d'attache PB de la biellette de direction, le point d'attache PM du moyeu et celui PA de l'actionneur. Le positionnement de ces trois points est imposé par les cinématiques de braquage en mode normal et la cinématique de freinage d'urgence, les angles de carrossage β et de pince δ étant couplés selon l'invention. Ainsi le point PB d'application de la biellette se trouve sur l'axe Au de pivot de la roue en situation d'urgence, en pointillés, qui fait un angle p avec l'axe Δc de pivot de la roue pour le carrossage en braquage classique, cet angle p étant imposé par le mode en situation d'urgence et défini à partir de la pince δ et du carrossage β par l'équation E7 suivante :
(E7) tan (p) = sin (δ) / sin (β)According to a first variant, the device used on a conventional vehicle, with rack-and-pinion steering, or "Steer-By-Wire" type with linked wheels or with a conventional steering column, comprises a wheel actuator for simultaneously controlling the angles. of clamp and camber imposed. FIG. 4a shows on the one hand the pivot axis Δ c of the wheel for the camber and, on the other hand, the pivot axis Δ B of the wheel for turning in normal mode, ie in conventional steering, which intersect perpendicularly to the point of attachment P M of the hub, and the wheel plane is then defined by its three attachment points, the point of attachment P B of the steering rod, the point of attachment P M of hub and that P A of the actuator. The positioning of these three points is imposed by the steering kinematics in normal mode and the emergency braking kinematics, camber angles β and clamp δ being coupled according to the invention. Thus the point P B Application of the link from the u axis of pivot of the wheel in an emergency situation, in dotted lines, which forms an angle p with the axis Δ c of pivot of the wheel to the camber in conventional steering, this angle p being imposed by the emergency mode and defined from the clamp δ and the camber β by the following equation E7: (E7) tan (p) = sin (δ) / sin (β)
Le point d'application PA de l'actionneur de carrossage piloté selon le procédé de l'invention est placé sur un axe ΔA de la roue, qui fait un angle v avec l'axe de pivot ΔB de la roue pour le braquage, défini pour obtenir l'effet de carrossage β induit lors du braquage. Les angles v et p sont définis par l'implantation des actionneurs.The application point P A of the camber actuator controlled according to the method of the invention is placed on an axis Δ A of the wheel, which makes an angle v with the pivot axis Δ B of the wheel for the steering, defined to obtain the camber effect β induced during the steering. The angles v and p are defined by the implantation of the actuators.
Selon une seconde variante, le dispositif de mise en œuvre du procédé sur un véhicule automobile équipé d'une direction de type « Steer-By-Wire » à braquage gauche-droite découplé, qui comporte déjà un actionneur dédié au pilotage de la pince, comprend de plus un actionneur dédié au pilotage du carrossage pour découpler les deux degrés de liberté. Sur la figure 4b sont représentés d'une part l'axe Δc de pivot de la roue pour le carrossage et d'autre part l'axe de pivot ΔB de la roue pour le braquage en mode normal sur lequel est situé le point d'application PAP de l'actionneur dédié au pilotage de la pince, ces axes se coupant perpendiculairement au point d'attache PM du moyeu, ainsi que le point d'application PAc de l'actionneur de carrossage qui va se trouver sur l'axe Δc de pivot de la roue pour le carrossage.According to a second variant, the device for implementing the method on a motor vehicle equipped with a decoupled left-right steering "Steer-By-Wire" type steering, which already comprises an actuator dedicated to driving the gripper, further includes an actuator dedicated to driving the camber to decouple the two degrees of freedom. FIG. 4b shows on the one hand the pivot axis Δ c of the wheel for the camber and, on the other hand, the pivot axis Δ B of the wheel for the deflection in the normal mode on which the point is located. applying P AP of the actuator dedicated to the control of the clamp, these axes intersecting perpendicularly to the point of attachment P M of the hub, and the application point P A c of the camber actuator which is going to Δ c find the pivot axis of the wheel camber.
D'après un exemple numérique extrait d'une cartographie établie pour un pneu de caractéristiques suivantes :From a numerical example taken from a map established for a tire with the following characteristics:
- rigidité en dérive D=1350 N/°- drift rigidity D = 1350 N / °
- rigidité du pneu en carrossage P=D/2- rigidity of the tire in camber P = D / 2
- effort longitudinal maximal délivré par le pneu FXmax = 10 000 N - effort transversal maximal délivré par le pneu FYmax = 9 000 N- maximum longitudinal force delivered by the tire F Xmax = 10 000 N - maximum transverse force delivered by the tire F Ymax = 9 000 N
- adhérence correspondant à une piste mouillée μ = 0.5 l'effort total longitudinal sera maximal pour un carrossage de 30° et une pince de 1 ,2°, soit un angle p égal à 2°. Cet effort longitudinal vaut alors 10 188 N, ce qui est supérieur à 10 000 N obtenu sans pince ni carrossage, et permet un gain en distance d'arrêt de 1 ,45 mètre.- adhesion corresponding to a wet track μ = 0.5 total longitudinal force is maximum for a camber of 30 ° and a clamp of 1, 2 °, an angle p equal to 2 °. This longitudinal force is then 10 188 N, which is greater than 10 000 N obtained without clamp or camber, and allows a gain in stopping distance of 1.45 meters.
Grâce à l'invention, la distance d'arrêt d'un véhicule automobile, lors d'un freinage en ligne droite, est sensiblement réduite par augmentation des efforts longitudinaux délivrés par les pneus des roues directrices obtenue par action simultanée sur la pince et le carrossage des roues.
Thanks to the invention, the stopping distance of a motor vehicle, during braking in a straight line, is substantially reduced by increasing the longitudinal forces delivered by the tires of the steering wheels obtained by simultaneous action on the clamp and the wheel camber.
Claims
1. Procédé de réduction active de la distance de freinage d'un véhicule automobile équipé d'au moins deux roues directrices et d'un système d'aide à la conduite, caractérisé en ce que, en cas de détection d'une situation d'urgence nécessitant un freinage maximal à partir d'informations venant du conducteur d'une part et liées à l'environnement du véhicule d'autre part, suivie d'une application de l'effort maximal de freinage sur les roues directrices effectuée par le conducteur assisté du système d'aide à la conduite, il comprend une étape de correction des angles des plans de roues directrices, par application simultanée de consignes de pince (δ) et de carrossage (β) sur les roues pour obtenir les efforts longitudinaux maximaux délivrés par les pneus et provoquant la décélération maximale du véhicule.A method of actively reducing the braking distance of a motor vehicle equipped with at least two steered wheels and a driving assistance system, characterized in that, in the event of detecting a situation of urgency requiring maximum braking from information coming from the driver on the one hand and related to the environment of the vehicle on the other hand, followed by application of the maximum braking force on the steering wheels carried out by the assisted driver of the driving assistance system, it comprises a step of correcting angles of the steering wheel planes, by simultaneous application of clamp (δ) and camber (β) settings on the wheels to obtain the maximum longitudinal forces delivered by the tires and causing the maximum deceleration of the vehicle.
2. Procédé de contrôle selon la revendication 1, caractérisé en ce que, pour le pneu de chacune des roues directrices, il détermine des consignes de pince (δ) et de carrossage (β) qui rendent maximal l'effort longitudinal total, généré par la dérive due à la pince et au carrossage, et délivré par ledit pneu dans la direction de déplacement du véhicule en sens inverse pour provoquer la décélération du véhicule, ces consignes étant choisies parmi les valeurs établies par cartographie en fonction du type de pneu et de l'adhérence, sachant que la rigidité du pneu (D) en dérive, la rigidité du pneu (P) en carrossage, les efforts maximaux longitudinal (FXmax) et latéral (FYmax), délivrés par le pneu, sont des données fixées.2. A control method according to claim 1, characterized in that, for the tire of each of the steered wheels, it determines gripping instructions (δ) and camber (β) that maximize the total longitudinal force, generated by the drift due to the gripper and the camber, and delivered by said tire in the direction of movement of the vehicle in the opposite direction to cause the deceleration of the vehicle, these instructions being chosen from the values established by mapping according to the type of tire and adhesion, knowing that the stiffness of the tire (D) derives from it, the rigidity of the tire (P) in camber, the maximum longitudinal (F Xmax ) and lateral (F Ymax ) forces, delivered by the tire, are fixed data. .
3. Procédé de contrôle selon la revendication 1, caractérisé en ce que les données provenant du conducteur sont par exemple la vitesse d'enfoncement ou l'effort exercé sur la pédale de frein, le temps de passage entre les pédales d'accélérateur et de frein, l'activation du système d'assistance au freinage d'urgence et les données sur l'environnement sont notamment la distance entre le véhicule et l'obstacle détecté, la vitesse de rapprochement, l'adhérence des pneus sur la route, le temps avant impact, délivrées par le système d'aide à la conduite équipant le véhicule associé à des capteurs embarqués.3. Control method according to claim 1, characterized in that the data from the driver are for example the driving speed or the force exerted on the brake pedal, the time of passage between the accelerator pedals and braking, the activation of the emergency braking assistance system and the environmental data are in particular the distance between the vehicle and the obstacle detected, the speed of approach, the adhesion of the tires to the road, the time before impact, delivered by the driver assistance system of the vehicle associated with on-board sensors.
4. Dispositif de mise en œuvre du procédé de contrôle selon l'une des revendications 1 à 3, caractérisé en ce qu'il est embarqué sur le véhicule et comprend un calculateur électronique qui reçoit des informations sur le conducteur et sur l'environnement du véhicule, qui détermine simultanément les valeurs optimales de la pince et du carrossage de chaque roue et qui commande au moins un actionneur par roue pour piloter les angles de pince et de carrossage.4. Device for implementing the control method according to one of claims 1 to 3, characterized in that it is embedded on the vehicle and comprises an electronic computer which receives information about the driver and the environment of the vehicle. vehicle, which simultaneously determines the optimal values of the pliers and camber of each wheel and which controls at least one actuator per wheel to control the angles of clamp and camber.
5. Dispositif de mise en œuvre selon la revendication 4, caractérisé en ce que, sur un véhicule classique, avec direction à crémaillère, ou de type « Steer-By-Wire » à roues liées ou avec colonne de direction classique, il comporte un actionneur par roue pour piloter simultanément les angles de pince (δ) et de carrossage (β) imposés, en ce que le point (PB) d'application de la biellette se trouve sur l'axe (Δy) de pivot de la roue en situation d'urgence, qui fait un angle (p) avec l'axe (Δc) de pivot de la roue pour le carrossage en braquage classique, cet angle (p) étant imposé par le mode en situation d'urgence et défini à partir de la pince (δ) et du carrossage (β) par l'équation suivante :5. Implementation device according to claim 4, characterized in that, on a conventional vehicle, with rack-and-pinion steering, or of the "Steer-By-Wire" type with bound wheels or with a conventional steering column, it comprises a wheel actuator for simultaneously controlling the imposed clamp (δ) and camber (β) angles, in that the point (P B ) of application of the connecting rod is on the pivot axis (Δy) of the wheel in an emergency, which makes an angle (p) with the wheel pivot axis (Δ c ) for the conventional steering camber, this angle (p) being imposed by the emergency mode and defined from the gripper (δ) and the camber (β) by the following equation:
tan (p) = sin (δ) / sin (β)tan (p) = sin (δ) / sin (β)
et en ce que le point d'application (PA) de l'actionneur de carrossage piloté est placé sur un axe (ΔA) de la roue, qui fait un angle (v) avec l'axe de pivot (ΔB) de la roue pour le braquage, défini pour obtenir l'effet de carrossage (β) induit lors du braquage.and in that the point of application (P A ) of the driven camber actuator is placed on an axis (Δ A ) of the wheel, which makes an angle (v) with the pivot axis (Δ B ) of the wheel for steering, defined to obtain the camber effect (β) induced during steering.
6. Dispositif de mise en œuvre du procédé de contrôle selon la revendication 4, caractérisé en ce que, sur un véhicule automobile équipé d'une direction de type6. Device for implementing the control method according to claim 4, characterized in that, on a motor vehicle equipped with a direction of type
« Steer-By-Wire » à braquage gauche-droite découplé, qui comporte déjà un actionneur dédié au pilotage de la pince, il comprend de plus un actionneur dédié au pilotage du carrossage pour découpler les deux degrés de liberté. "Steer-By-Wire" decoupled left-right, which already has an actuator dedicated to driving the clamp, it further comprises an actuator dedicated to controlling the camber to uncouple the two degrees of freedom.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0600817 | 2006-01-30 | ||
| FR0600817A FR2896754B1 (en) | 2006-01-30 | 2006-01-30 | METHOD FOR REDUCING THE BRAKING DISTANCE OF A MOTOR VEHICLE AND DEVICE FOR IMPLEMENTING SAID METHOD |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2007085751A1 true WO2007085751A1 (en) | 2007-08-02 |
Family
ID=37022894
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FR2007/050604 WO2007085751A1 (en) | 2006-01-30 | 2007-01-03 | Method for reducing the braking distance of a motor vehicle and device for implementing it |
Country Status (2)
| Country | Link |
|---|---|
| FR (1) | FR2896754B1 (en) |
| WO (1) | WO2007085751A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9043071B1 (en) | 2013-08-22 | 2015-05-26 | Google Inc. | Steering-based scrub braking |
| CN108248686A (en) * | 2018-01-31 | 2018-07-06 | 肇庆学院 | A kind of emergency braking control method based on four-wheel independent steering driving line traffic control automobile |
| US10085855B2 (en) | 2010-05-14 | 2018-10-02 | Beacon Biomedical, Llc | Surgical instrument for implant insertion |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5559698A (en) * | 1993-08-06 | 1996-09-24 | Hyundai Motor Company | System for dynamically adjusting the toe angle of vehicle wheels |
| EP0992373A2 (en) * | 1998-10-09 | 2000-04-12 | Robert Bosch Gmbh | System and method for shortening the braking distance and improving traction in motor vehicles |
| DE10100743A1 (en) * | 2000-01-14 | 2001-07-19 | Continental Teves Ag & Co Ohg | Regulating braking and driving stability of moving vehicle involves controlling individually steerable wheels to wholly or partially generate computed braking torques or forces |
| EP1145936A1 (en) * | 2000-04-13 | 2001-10-17 | Continental Aktiengesellschaft | Device for adjusting the toe-in of the wheels of a vehicle |
| DE10253261A1 (en) * | 2002-11-15 | 2004-05-27 | Volkswagen Ag | Braking system for road vehicle on surfaces of different coefficient of friction has separate sensors for each wheel to measure individual coefficients of friction, connected to control computer |
| DE10352212A1 (en) * | 2003-07-11 | 2005-02-03 | Volkswagen Ag | Motor vehicle, has suspension and/or damping device, and lifting device receiving control signal and raising and/or lowering vehicle body in controlled way in optimal accident position |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63275458A (en) * | 1987-05-01 | 1988-11-14 | Toshihiro Tsumura | Braking device for car |
| US5438515A (en) * | 1992-10-14 | 1995-08-01 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Alignment control unit and control method for an automotive suspension |
| DE10244140B4 (en) * | 2002-09-23 | 2017-04-27 | Bayerische Motoren Werke Aktiengesellschaft | Arrangement of a steering angle of a steerable vehicle wheel causing actuator |
| JP4825668B2 (en) * | 2004-10-06 | 2011-11-30 | 日立オートモティブシステムズ株式会社 | Electric brake device |
| US7991532B2 (en) * | 2004-12-27 | 2011-08-02 | Equos Research Co., Ltd. | Wheel control device and control device |
-
2006
- 2006-01-30 FR FR0600817A patent/FR2896754B1/en not_active Expired - Fee Related
-
2007
- 2007-01-03 WO PCT/FR2007/050604 patent/WO2007085751A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5559698A (en) * | 1993-08-06 | 1996-09-24 | Hyundai Motor Company | System for dynamically adjusting the toe angle of vehicle wheels |
| EP0992373A2 (en) * | 1998-10-09 | 2000-04-12 | Robert Bosch Gmbh | System and method for shortening the braking distance and improving traction in motor vehicles |
| DE10100743A1 (en) * | 2000-01-14 | 2001-07-19 | Continental Teves Ag & Co Ohg | Regulating braking and driving stability of moving vehicle involves controlling individually steerable wheels to wholly or partially generate computed braking torques or forces |
| EP1145936A1 (en) * | 2000-04-13 | 2001-10-17 | Continental Aktiengesellschaft | Device for adjusting the toe-in of the wheels of a vehicle |
| DE10253261A1 (en) * | 2002-11-15 | 2004-05-27 | Volkswagen Ag | Braking system for road vehicle on surfaces of different coefficient of friction has separate sensors for each wheel to measure individual coefficients of friction, connected to control computer |
| DE10352212A1 (en) * | 2003-07-11 | 2005-02-03 | Volkswagen Ag | Motor vehicle, has suspension and/or damping device, and lifting device receiving control signal and raising and/or lowering vehicle body in controlled way in optimal accident position |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10085855B2 (en) | 2010-05-14 | 2018-10-02 | Beacon Biomedical, Llc | Surgical instrument for implant insertion |
| US9043071B1 (en) | 2013-08-22 | 2015-05-26 | Google Inc. | Steering-based scrub braking |
| CN108248686A (en) * | 2018-01-31 | 2018-07-06 | 肇庆学院 | A kind of emergency braking control method based on four-wheel independent steering driving line traffic control automobile |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2896754B1 (en) | 2008-04-11 |
| FR2896754A1 (en) | 2007-08-03 |
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