FR2807856A1 - METHOD FOR ASSISTING THE DRIVING OF A MOTOR VEHICLE - Google Patents

Abstract

Acquisition process receives values (V1-Vp) for physical values representing the vehicle state. From the values, the extent of a safety zone in front of the vehicle is determined. Determined zone is then displayed on the windscreen of the vehicle and aids a driver in avoiding an obstacle that initially occurs in the safety zone in front of the vehicle and then seems likely to move into a danger zone immediately in front of the driver.

Description

The present invention relates, in general, to a method

  providing increased security for

  motor vehicle drivers.

  More specifically, the invention relates to a method for assisting in the safe driving of a vehicle traveling on a taxiway and comprising a passenger compartment protected by a windshield which allows a driver to receive an image of the taxiway , this method comprising an acquisition procedure consisting in collecting, by measurement or estimation, values of physical parameters representing instantaneous conditions of running of the vehicle, and a processing procedure consisting in combining them, in accordance with predetermined physical models, the values collected to at least partially locate a border between a dangerous interference zone immediately surrounding the vehicle and a safety zone situated at a distance from the vehicle and extending beyond

  from the hazardous interference zone.

  Thanks to the development of electronics, motor vehicle driving assistance methods are nowadays more and more widespread, and may include

  more and more features.

  Driving assistance methods of the type defined above are notably known, in particular when they use a radar, under the generic designation of "intelligent cruising systems", and are even more known under the Anglo-Saxon designation " Intelligent cruise

  control ", often abbreviated as" ICC ".

  Such systems, mainly dedicated to monitoring the environment of the vehicle and in particular responsible for the prevention of risks linked to the presence of fixed or mobile obstacles on the traffic lane, are for example described in the patent documents EP - 0 720

  928, EP - 0 764 279, EP - 0 684 486, US - 5 493 302, EP - 0

  706 667, EP - 0 569 095, or also GB - 2 267 544.

  Other driving assistance methods, usable in combination with ICC systems but essentially designed

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  to monitor the vehicle-pavement couple and control the instantaneous stability of the vehicle, are known by various names such as the French abbreviation "CDS" (dynamic stability control), the German abbreviation "FDR", or the Anglo-Saxon abbreviations "DCC" (Dynamic

  Chassis Control) or "DDC" (Driving-Dynamics Control).

  Such systems are for example described in the

  patent documents FR - 2,719,536, FR - 2,719,537, or US -

4,984,649.

  Still other systems, for example illustrated by patent FR-2 618 743, have been known since a more distant date under various names such as "ABS" or "ASR" depending on the functions which are more specifically assigned to them, the systems ABS to prevent wheel locks when braking, and ASR systems to prevent wheel spin caused by acceleration

  excessive with regard to the grip offered by the road.

  Today, these systems are not only capable of detecting critical situations and defining their limits, but they are also designed, in general, to make these critical situations disappear as much as possible by acting directly on the organs. suitable for the vehicle, for example on the brakes, on the engine, on the suspension,

  or even on the direction of the rear wheels at least.

  Despite the major and obvious interest of these systems, their extensive application comes up against

several difficulties.

  On the one hand, if any driver can easily agree to delegate to an electro-mechanical system the task of filling

  a security function that he is unable to perform himself

  even, like for example the modulation of the braking pressure to several hertz to avoid a locking of the wheels, many drivers are on the other hand more reluctant to give to an electronic circuit the possibility of taking itself, and of applying, driving decisions, such as the ability to take the

  decision to brake or accelerate the vehicle.

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  On the other hand, some of these systems, such as for example the ICC systems which include a radar, are not

  accessible only at relatively high costs.

  However, the safety gain that vehicles equipped with such systems are capable of bringing does not only depend on the technical level of their own equipment, but it also depends on that of the vehicles among which they circulate. Also, not only is the high cost of certain systems, considered in all of their functionalities, a factor which limits their exploitation, but it is also a factor likely to

  limit, for the time being, their effectiveness in concrete terms.

  Last but not least, it now seems established that drivers tend to drive at a constant perceived risk, and that the feeling of safety which they get from the presence of an automatic driving assistance system on their vehicles, for example an ABS system, incites them to take more and more important risks as the conviction grows that these systems are capable

  to avoid these risks in all circumstances.

  In this context, the aim of the present invention is to propose a system for assisting safe driving capable of bringing, on at least some of the aspects mentioned above, a real advantage over

existing systems.

  To this end, the method of the invention, moreover in accordance with the generic definition given by the preamble above, is essentially characterized in that it comprises a viewing procedure which itself includes a mixing operation consisting to superimpose, like the taxiway received by the driver, a materialization of the border between the dangerous interference zone and the safety zone, which allows the driver to bring to driving the vehicle, in real time and interactively, any corrective measure likely to prevent an obstacle initially visible in the area of

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  security comes to life with an apparent movement that risks bringing it

  into the hazardous interference zone.

  In an advantageous embodiment of the invention, the mixing operation is implemented by projecting a bright image of the border between the area on the windshield

  dangerous interference and safety zone.

  The method of the invention thus uses a known technology, called a "head-up" display, in a context which gives it specific advantages and

  substantial in terms of security.

  Preferably, the border includes, at least when the vehicle is approaching a turn, a lateral terminal defining a limit curvature trajectory of the vehicle, and a frontal terminal defining a minimum braking distance of

  safety on the taxiway.

  One of the advantages of the process of the invention is that it essentially involves only operations which may already be carried out on the vehicle to which it applies, so that it does not represents that a cost

moderate differential.

  Thus, the acquisition and processing procedures of the method of the invention can, together, be at least partially made up of acquisition and processing operations implemented in a method (ICC) aiming at least to control the speed or the direction of the vehicle

depending on its environment.

  The acquisition and processing procedures of the process of the invention can also, together, be at least partially made up of acquisition and processing operations implemented in a process (FDR) aiming at least to dynamically control vehicle stability. The acquisition and processing procedures of the process of the invention can also, together, be at least partially made up of acquisition and processing operations implemented in a process (ABS) aimed at

  least to avoid locking the vehicle wheels.

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  In a more elaborate embodiment of the method of the invention, the acquisition procedure can comprise an operation for acquiring navigation data, the processing procedure then comprising an operation for exploiting navigation data, suitable for modifying the border, at a given time, depending on the obstacles that the vehicle must encounter on the taxiway at

a moment later.

  The light image of the border is for example formed by illuminating, by a light source, a matrix of mirrors controlled by an electronic addressing circuit, the windshield on which the light image of the border is projected advantageously having, in a vertical plane,

a wedge-shaped section.

  Finally, to increase the reliability of the method of the invention, the display procedure preferably comprises a mixing control operation to control the mixing operation, and a calibration operation to determine and supply to the control operation of mixing of the geometrical parameters allowing to take at least into account, for the projection of the luminous image of the

  border, the position of the driver in relation to the barrier

  broken. Other characteristics and advantages of the invention

  will emerge clearly from the description made of it

  below, by way of indication and in no way limitative, with reference to the appended drawings, in which: - Figure 1 is a block diagram of the whole process of the invention, illustrating both essential operations and procedures, optional operations and procedures, and known operations and procedures external to the invention; - Figure 2 is a diagram illustrating the result of the implementation of the method of the invention; and - Figure 3 is a diagram showing a system

  optics usable in the context of the invention.

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  The invention relates to a method for assisting safe driving for a motor vehicle, this vehicle being driven by a driver K (FIG. 3), being designed to travel on a traffic lane R (FIG. 2), and comprising so conventional passenger compartment protected at the front by a transparent windshield W (Figure 3), which allows the driver to receive an Imgl image of the taxiway R. This process firstly comprises, in a manner known per se, a procedure for PAQ acquisition consisting in collecting, by measurement or estimation, values Vl to Vp of physical parameters which represent instantaneous conditions of

vehicle rolling.

  These physical parameters can notably include the speed of the vehicle, its mass, the slip rate of the wheels, the angle of rotation of the steering wheel, the ambient humidity rate, the adhesion of the vehicle to the ground, the centrifugal force, etc. In general, these parameters are preferably those which are provided, in real time, by the driving assistance methods existing on the vehicle, such as the

  ICC, FDR, ABS, ASR, or other systems.

  Otherwise, these parameters can at least include parameters available on all vehicles, such as speed, and manufacturer's parameters, stored one

  once and for all, such as the empty mass of the vehicle.

  The method of the invention also includes a processing procedure PT, which consists in combining the values Vl to Vp of the different parameters with each other,

  according to pre-established physical models.

  Again, the operations of this processing procedure may include at least some of the operations that are performed, in real time, by the existing driver assistance methods on the vehicle, such as systems

ICC, FDR, ABS, ASR, or others.

  However, while the processing operations carried out by these known systems aim to produce

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  signals, such as El, E2, E3, E5, E7, Ek, which are used, within the framework of a PCA actuation control procedure, to control actuation control operations OCA1, OCA2, OCAn used for directly control mechanical or hydraulic components of the vehicle, the method of the invention does not take into account the PCA actuation control procedure and only includes processing operations which aim to produce signals, such as E4 to E8 , and Ek, which define a spatial boundary F between a dangerous interference zone Zid immediately surrounding the vehicle, and a safety zone Zs which is located at a distance from the vehicle and which extends beyond the zone

of dangerous interference Zid.

  In other words, while at least some of the signals traditionally originating from the PT processing procedure and used in the PCA actuation control procedure represent respective deviations between normal operating zones of various components of the vehicle and real operating zones of these organs, the method of the invention, the purpose of which is beyond that which the PCA actuation control procedure aims at, is only interested in the signals originating from the PT processing procedure which are representative of '' a distance between an obstacle and the vehicle, a relative position or orientation of an obstacle and the vehicle, and the level of risk associated with the existence of this obstacle, as a function of its distance, its position or orientation relative to the vehicle. More specifically, the invention is concerned with the signals, originating from the processing PT, which make it possible to delimit, by means of the border F, the zone of dangerous interference Zid defined as being that which must remain free from any obstacle so that the vehicle safety can be assured. In this context, the method of the invention includes a PV display procedure allowing the driver K

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  to immediately perceive the border F which separates this

  Zid dangerous interference zone from Zs safety zone.

  To this end, the PV display procedure includes a MIX mixing operation which consists of superimposing, on the image Imgl of the traffic lane that the driver K receives through the windshield W, a materialization of the border F. Thanks to the invention, the driver K can thus bring to the driving of his vehicle, in real time and interactively, any corrective measure capable of preventing an obstacle which he initially perceives in the safety zone Zs from moving. , in his field of vision, even in

  the Zid hazardous interference zone.

  This display is advantageously obtained by the technique known in itself under the name "head-up display" and for example described in patent documents.

FR - 2 734 653, or FR - 2 678 079.

  Thus, the mixing operation MIX is preferably implemented by projecting on the windshield W a bright image Img2 of the border F between the interference zone

  dangerous Zid and the safety zone Zs.

  As shown in FIG. 3, the light image Img2 of the border is for example formed by illuminating, by a light source SL, a matrix of mirrors MM controlled by an electronic addressing circuit CE, the matrix of mirrors being able to be constituted by the product marketed by the Texas Instruments Company under the name of "Digital Mirrors

  Display ", which includes 800 lines of 600 small mirrors.

  In this case, the implementation of the MIX mixing operation may require an OCM mixing control operation (FIG. 1), suitable for defining the coordinates of the mirrors to be controlled and for controlling the MIX mixing operation by transmitting these coordinates to an electronic circuit

of CE addressing.

  To remove stray images, the screen

  breeze W can receive specific treatment, such as

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  metal deposition, machining, or rolling, these techniques

  having already been described in the prior art.

  In the context of the invention, good results can be obtained by using a laminated windshield W which has, in a vertical plane, a wedge-shaped section, and more precisely a windshield whose faces converge toward each other, downward, at an angle of

a few degrees.

  As shown in Figure 2, the border F includes at least one front terminal BF, which defines a minimum safety braking distance on taxiway R. To keep a safety distance between the vehicle it is following and the vehicle that he is driving, the driver K must therefore remain far enough from the vehicle he is following so that the image of the latter always appears above the front terminal BF of the border F. If the vehicle includes means allowing '' assess the turning radius of the wheels and the transverse grip limit of the vehicle on the track, the border F may also include, at least when the vehicle approaches a turn, one or two lateral bollards such as BL1 and BL2, allowing define a limit curvature path for the vehicle. To avoid inadvertent skidding of the vehicle, the driver K must therefore ensure that his target trajectory is always both on taxiway R and in the safety zone bordered by the side terminal (s) BL1 and BL2, and must therefore avoid having to take a turn whose radius of curvature would be less than that of the trajectory of limit curvature materialized by the or

terminals BL1 and BL2.

  As the braking distance is defined in front of the vehicle whereas it varies according to the instantaneous rolling conditions of the latter, and in particular according to whether it is traveling in a straight line, that it is taking a turn, that it is on a slope uphill or downhill, it may be beneficial to have track information

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  traffic upstream of the vehicle in order to optimize the definition of the border F. To this end, the PAQ acquisition procedure can, in a manner known per se, include an OANav operation for acquiring navigation data II to Iq, by example transmitted by local transmitters installed on taxiway R or extracted from a stored map, linked to on-board instrumentation providing the coordinates

vehicle snapshots.

  In such a case, the processing procedure PT comprises an operation for using the navigation data II to Iq, denoted OTNav (FIG. 1) and making it possible, at each instant T, to modify the border F as a function of obstacles (descents, turns, traffic jams, etc.) that the vehicle must meet on taxiway R at an instant

subsequent T + dT.

  To further optimize the precision and reliability of the method of the invention, the PV display procedure can include (FIG. 1) a CAL calibration operation to determine and supply the OCM mixing control operation with geometric parameters G1 to Gt allowing at least to take into account, for the projection of the light image Img2 of the border F. the position of the conductor K relative to the windshield W. The calibration operation CAL, which does not need to be performed only once for a given driver, adopting a given position in a given vehicle, can be triggered at will by the driver K and performed automatically. For example, the geometric parameters Gi to Gt can be obtained from images of several test borders projected on the windshield W, these images being collected on a miniature camera installed on a spectacle frame worn by the driver during the time

  of this CAL calibration operation.

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Claims (10)

CLAIMS.   1. Method for assisting in the safe driving of a vehicle traveling on a traffic lane (R) and comprising a passenger compartment protected by a windshield (W) which allows a driver (K) to receive an image (Imgl) of the traffic lane, this method comprising an acquisition procedure (PAQ) consisting in collecting, by measurement or estimation, values (Vl to Vp) of physical parameters representing instantaneous vehicle running conditions, and a processing procedure ( PT) consisting in combining together, in accordance with pre-established physical models, the values collected (Vi to Vp) to at least partially locate a border (F) between a zone of dangerous interference (Zid) immediately surrounding the vehicle and a zone safety device (Zs) located at a distance from the vehicle and extending beyond the dangerous interference zone (Zid), characterized in that it also includes a visualization procedure (PV) incl owing to a mixing operation (MIX) consisting of superimposing, on the image (Imgl) of the traffic lane received by the driver (K), a materialization of the border (F) between the zone of dangerous interference (Zid) and the safety zone (Zs), which allows the driver (K) to take driving action, in real time and interactively, any corrective measure to prevent an obstacle initially visible in the safety zone (Zs) is animated by an apparent movement likely to bring it into the zone dangerous interference (Zid).   2. A driving assistance method according to claim 1, characterized in that the mixing operation (MIX) is implemented by projecting on the windshield (W) a bright image (Img2) of the border ( F) between the area   dangerous interference (Zid) and safety zone (Zs).   3. Driving assistance method according to one   any one of the preceding claims, characterized in   that the border (F) between the dangerous interference zone 12 2807856   (Zid) and the safety zone (Zs) includes, at least when the vehicle approaches a turn, a lateral terminal (BL1, BL2)   defining a limit curvature path of the vehicle.   4. Driving assistance method according to one   any one of the preceding claims, characterized in   that the border (F) between the dangerous interference zone (Zid) and the safety zone (Zs) includes a front terminal (BF) defining a minimum safety braking distance on the traffic lane.   5. Driving assistance method according to one   any one of the preceding claims, characterized in   that the acquisition (PAQ) and processing (PT) procedures are, together, at least partially made up of acquisition (OAQ1 to OAQp; OANav) and processing (OT1 to OTm; OTNav) operations implemented in a process (ICC) aimed at least at controlling speed or direction   of the vehicle according to its environment.   6. Driving assistance method according to one   any one of the preceding claims, characterized in   that the acquisition (PAQ) and processing (PT) procedures are, together, at least partially made up of acquisition (OAQ1 to OAQp; OANav) and processing (OT1 to OTm; OTNav) operations implemented in a process (CDS or FDR) aiming at least to dynamically control vehicle stability.   7. Driving assistance method according to one   any one of the preceding claims, characterized in   that the acquisition (PAQ) and processing (PT) procedures are, together, at least partially made up of acquisition (OAQ1 to OAQp; OANav) and processing (OT1 to OTm; OTNav) operations implemented in a method (ABS) aimed at least at preventing a locking of the wheels of the vehicle. 8. Driving assistance method according to one   any one of the preceding claims, characterized in   that the acquisition procedure (PAQ) includes an operation (OANav) for the acquisition of navigation data (II to Iq) and 13 2807856   in that the processing procedure (PT) includes an operation for exploiting (OTNav) the navigation data (II to Iq), capable of modifying the border (F), at a given instant (T), depending on the obstacles that the vehicle must meet on the taxiway at a later time (T + dT). 9. Driving assistance method according to one   any of the preceding claims combined with   claim 2, characterized in that the light image (Img2) of the border is formed by illuminating, by a light source (SL), a matrix of mirrors (MM) controlled by an electronic addressing circuit (CE), and in that the windshield (W) on which the light image (Img2) of the border is projected is laminated and present, in a plane   vertical, a wedge-shaped section.   10. Driving assistance method according to one   any of the preceding claims combined with   claim 2, characterized in that the display procedure (PV) comprises a mixing control operation (OCM) for controlling the mixing operation (MIX), and a calibration operation (CAL) for determining and supplying the operation of mixing control (OCM) of the geometric parameters (G1 to Gt) making it possible to take at least into account, for the projection of the light image (Img2) of the   border, the position of the conductor (K) in relation to the barrier breeze (W).