METHOD AND DEVICE FOR MONITORING A CREEP SPEED MODE OF A VEHICLE AS A FUNCTION OF A DISTANCE BETWEEN THE VEHICLE OF AN OBSTACLE

The invention relates to the vehicles, which are automated said, and more particularly the control of a so-called mode " creep rotational > > (or creeping) within such vehicles.

To achieve this by " automated vehicle > > both a vehicle having a driving means for the automatic adaptation of the transmission ratio of the power unit (or GMP) to the wheels (such as a robotized gearboxes), that a vehicle does not need this type of control system (such as a GMP all-electric vehicle). Therefore, the invention relates to, in particular all-electric vehicle powertrain, the hybrid powertrain vehicles, and vehicles powertrain automation mechanism the transmission ratio (such as a manual gearbox robotic, a twin-clutch gearbox, an automatic gearbox or a continuously variable transmission).

Furthermore, used herein, by " creep speed mode > > (or creeping), an operating mode of the GMP for moving the vehicle, low-speed (typically 5 to 12 km/h on the flat) and autonomously, by providing a variable torque as soon as the driver no longer acts on the brake and accelerator pedals.

The displacement mode (or rolling) autonomous (i.e. without action by the driver) was originally designed for vehicles with an automatic gearbox with torque converter, and was then implanted in many other automated vehicles. The procedure allows the driver to more easily navigate the vehicle, as actuating temporarily that the brake pedal.

On a vehicle equipped with an automatic transmission, the creeping is a result of the operation of the torque converter which converts the rotational speed difference between the input shaft of the automatic transmission (which is connected to the rotary engine to a non-zero speed) and the output shaft of the automatic transmission (which is coupled to the wheels torque). On the other automated vehicles, the creeping may be performed by a driving members for approximate the behavior of a vehicle torque converter.

The creeping is useful, but, alas, it has several disadvantages: a premature wear of the clutch when the vehicle is equipped therewith, heating of certain organs of the GMP (such as the electric machine or the clutch), and an overconsumption (due to heat dissipation of energy in the brakes) when active brake.

In order to limit the impact of these disadvantages, it has been proposed a strategy for deactivating the creeping when the vehicle is stopped or when the driver actuates the brake pedal for a certain period of time. The creeping is then activated again gradually when the driver stops activating the brake pedal.

The slow turn-on of the creeping although allows advance the vehicle safely, but, unlike the creeping offered by an automatic transmission, it does not permit finely adjusted, or in any case very difficult, the acceleration and speed of the vehicle by actions on the brake pedal. Indeed, each action thereon disables the creeping to avoid heating and wear of certain organs of the GMP, and thus the driver is frequently forced to work briefly on the accelerator pedal to limit the uptake of speed of the vehicle (in particular when parking manoeuvres), which causes unpleasant surges of vehicle occupants and reduced the convenient when an obstacle is substantially on the path of the vehicle.

The invention thus particularly to improve the situation.

It proposes in particular a method, on the one hand, for controlling a so-called mode " creep rotational > > of an automated vehicle, suitable for moving the latter to low speed by providing a variable torque produced by the power unit without action of its conductor on the brake and accelerator pedals, and, on the other hand, comprising, when the driver stops activating the brake pedal so that the vehicle moves in a path, determining for this embodiment creep speed, depending on the distance between a portion of the vehicle of any obstacle located in the vicinity of this path, a torque profile which is adapted to move the vehicle according to a speed profile associated.

Therefore, can be a reduction of the velocity of the vehicle when it is in a creep speed (or creep) and that an obstacle is detected substantially on its way, and the speed reduction may be even greater than the distance vehicle-obstacle is small,

The control method according to the invention can include other features that can be taken separately or in combination, and in particular:

-the profile of torque can be selected from a group comprising at least two predefined torque profiles respectively associated with-distance intervals predefined vehicle-snag;

>this group of torque profiles may include at least i) a first torque profile, associated with a first vehicle-snag interval of distances greater than or equal to a first threshold and comprising a first portion increasing substantially linearly at a first slope, followed by a second portion substantially constant and itself followed by a third portion decreasing monotonic, ii) a second torque profile, associated with a second interval of distances vehicle-obstacle strictly less than the first threshold and greater than or equal to a second threshold lower than the first threshold, and comprising a first substantially linearly increasing portion at a second slope that is less than the first slope, followed by a second portion substantially constant and itself followed by a third portion decreasing monotonic, iii) a third torque profile, associated with a third interval of distances vehicle-obstacle strictly less than the second threshold and greater than or equal to a third threshold lower than the second threshold, and comprising a first substantially linearly increasing portion according to a third slope less than the second slope, followed by a second portion substantially constant and itself followed by a third portion decreasing monotonic, and iv) a fourth torque profile, associated with a fourth interval of distances vehicle-obstacle strictly less than the third threshold and greater than or equal to a fourth threshold lower than the third threshold, and comprising a first substantially linearly increasing portion according to a fourth slope less than the third slope, followed by a second portion decreasing monotonic;

the distance-vehicle-obstacle can be determined from information acquired by acquisition means fitted to the vehicle.

The invention also relates to a device, for controlling the creep speed mode of an automated vehicle, and comprising control means arranged, when the driver of the vehicle stops activating the brake pedal so that the vehicle moves in a path, for determining for this embodiment creep speed, depending on the distance between a portion of the vehicle of any obstacle located in the vicinity of this path, a torque profile which is adapted to move the vehicle according to a speed profile associated.

For example, the control means may be arranged to select the torque profile in a group which comprises at least two predefined torque profiles respectively associated with-distance intervals predefined vehicle-snag.

This group of torque profiles may include at least one of the four torque profiles above.

The invention also provides a vehicle, optionally of automotive type, and having a power plant and a control device of the type above.

For example, the train may be selected from (at least) a powertrain all-electric, a hybrid powertrain, and a powertrain with mechanism to automate the gear ratio.

Other features and advantages of the invention will appear from a review of the detailed description below, and of the accompanying drawings, on which:

-figure 1 illustrates schematically and functionally an automated vehicle having a power plant, a supervisor powertrain equipped with a monitoring device according to the invention, and a parking assistance system,

-figure 2 illustrates within a first temporal evolution four torque profiles (C1 to C4) capable of being used in the presence of four distances respectively different vehicle-object, and

-figure 3 illustrates within a second temporal evolution pattern four speed profiles (C1 'to C4') associated respectively with the four torque profiles (C1 to C4) of Figure 2.

The object of the invention to provide a control method, and a control device D associated, for controlling the creep speed mode (or creeping) of an automated vehicle V having a power plant and of the brake and accelerator pedals.

In the following, is considered, by way of non-limiting example, that the vehicle V is automated of automotive type. It is, for example, in a car. But the invention is not limited to this type of automated vehicle. In effect any type of terrestrial automated vehicle having a powertrain, on the one hand, having at least one thermal engine MT and/or at least one motor (or machine) auxiliary (electrical or hydraulic or compressed air) coupled to energy storage means, and, on the other hand, includes a drive system organs responsible for adapting automatically the transmission ratio of the power unit to the wheels, or having no need of such type of control system. Therefore, the invention relates to, in particular all-electric vehicle powertrain, the hybrid powertrain vehicles, and vehicles powertrain automation mechanism the transmission ratio.

Furthermore, is considered in the following, by way of non-limiting example, that the powertrain includes a mechanism to automate the transmission ratio in the form of a manual gearbox BV robotic. But the invention is not limited to this type of mechanism to automate the transmission ratio. In effect, in particular, any type of mechanism to automate the transmission ratio, and in particular the twin-clutch transmission (or DCT), automatic transmissions and continuously variable transmissions.

It has schematically represented in Figure 1 a vehicle V (automated) having a power plant (optionally overrunning), a supervisor CS own to supervise the operation of the powertrain, and a control device D according to the invention,

The powertrain includes in particular, herein, a heat engine MT, a drive shaft, a clutch EM, a gearbox BV, and a transmission shaft.

MT The heat engine includes a crankshaft (not shown) rigidly connected to the motor shaft to drive the latter in rotation.

The gearbox BV comprises (herein) an input shaft and an output shaft to be coupled to one another. The input shaft is for receiving the engine torque via the clutch EM (which is coupled to the motor shaft). The output shaft is for receiving the engine torque via the input shaft to communicate to the drive shaft to which it is coupled and which is indirectly coupled to wheels of the vehicle V. The input shaft and the output shaft each comprise gears (not shown) for assembly selectively participate in the definition of the selected different speeds of the gearbox BV.

The operation of the organs of the GMP is controlled by the supervisor CS which may be in the form of a computer (preferably dedicated).

As described above, it is proposed to arrange in the vehicle V inspection for controlling its creep speed mode (or creeping)

Such method can be implemented by the monitoring device D, and in particular by control means MC that comprises the latter (D). In the non-limiting example shown in Figure 1, the control device is part of the supervisor D CS. But this is not a requirement. The device (control) D could in effect be a supervisor equipment that is coupled to the CS, directly or indirectly. Therefore, the control device D can be made in the form of software modules (or computer or "software > >), or a combination of electronic circuits (or" hardware > >) and of software modules.

It is emphasized that the creep speed mode is for moving the vehicle V at a low speed providing a variable torque produced by the power unit without the operator acts on its brake and accelerator pedals.

The control method, according to the invention, is implemented when the driver ceases to act on the brake pedal so that the vehicle V moves in a path (forward or backward) after being substantially stopped, and when the single conductor does not act on the accelerator pedal.

The method includes determining for the mode of creep speed, as a function of a distance [...] that separates a portion of the vehicle V of any obstacle O located in the vicinity of its path (forward or backward), a torque profile which is adapted to move the vehicle V according to a speed profile associated.

The path is defined by a direction and a direction (forward or backward).

For example, the distance vehicle-snag [...] is determined between the front portion of the vehicle V PV (for example its bumper shield or front) and the obstacle O when the path is towards the front of the vehicle V, and the distance is determined vehicle-snag [...] PR between the rear portion of the vehicle V (for example its shield or rear bumper) and the obstacle O when the path is towards the rear of the vehicle V.

Vehicle-snag [...] This distance is determined from information that is acquired by acquisition means May installed in the vehicle V into at least a suitable point of its front parts PV and rear PR. It should be noted that the vehicle V may be means for acquiring May installed in its front part by PV and cannot determine that the distance vehicle-snag [...] in front of the vehicle V, or that acquisition means May installed in its rear part by PR and cannot determine that the distance vehicle-snag [...] behind the vehicle V, or acquisition means May installed in its front and rear and PV PR in this case the distances can be determined vehicle-snag [...] are located in front of and behind the vehicle V. The latter situation is particularly that which is illustrated, but not limited to, in the example of Figure 1.

May The acquisition means may include means for analysis by waves, such as radar or sonar detectors, and/or at least one camera for viewing. For example, there may be provided means of analysis by waves MA1 (i = 1) PV implanted in the front part of the vehicle V (for example in the bumper or shield), and at least one camera for viewing MA2 (i = 2), said recoil, implanted in the rear portion of the vehicle V. PR Alternatively, can be used in the front portion PV at least one camera for viewing before instead analysis means by waves MA1. Also, can be used in the rear part PR analysis means by waves instead of an observation camera rear MA2.

The analysis means by waves provide data inspection from which can be generated a mapping 2D, 3D 2,5D or from the external environment of the vehicle V, and deduced a distance vehicle-snag [...] -The observation cameras provide image data from which can be deduced a distance vehicle-snag [...] -

May These acquisition means can, optionally not limited and as shown in Figure 1, be part of a parking assistance system SA which also comprises processing means MT for determining the distances vehicle-snag [...] -Said processing means MT can, for example, be arranged in the form of a computer, or be part of a computer in the vehicle V. implanted

The information acquired by the acquisition means May can, for example and not limited as shown in Figure 1, be transmitted to the processing means MT via a communication network RC implanted in the vehicle V, such as optionally multiplexed, and to which is also connected the supervisor CS. In this case, the processing means MT provide D to the control device, and more particularly to its control means MC, via the communication network RC, each vehicle-snag [...] distance that they have determined, optionally to device request D control.

It should be noted that in an alternative embodiment, the acquisition means May and the processing means MT could be part of the control device D.

For example, the control means MC can be arranged to select the torque profile that is to be supplied to the GMP from a group comprising at least two predefined torque profiles respectively associated with-distance intervals vehicle-snag predefined [...].

For example, the group may include four predefined torque profiles. This example is illustrated in the diagram in temporal variation of Figure 2.

In this example, the group of predefined torque profiles comprises:

-a first torque profile C1 (formed by a continuous broken line) which is associated with a first interval of distances vehicle-snag [...] greater than or equal to a first threshold S1, and including a first portion increasing substantially linearly at a first slope P1, followed by a second portion substantially constant (herein equal to a maximum torque cm_{3 x}) and itself followed by a third portion decreasing monotonic,

-a second torque profile C2 (formed by a chain line) which is associated with a second interval of distances vehicle-snag [...] strictly less than the first threshold S1 and greater than or equal to a second threshold S2 lower than the first threshold S1, and including a first portion increasing substantially linearly at a second slope that is less than the first slope P2 P1, followed by a second portion substantially constant (herein equal to the maximum torque cm_{3 x}, although this is not mandatory) and itself followed by a third portion decreasing monotonic (herein equal to the third portion of the first torque profile C1, although this may not be required),

-a third torque profile C3 (formed by a dotted line), which is associated with a third interval of distances vehicle-snag [...] strictly less than the second threshold S2 and greater than or equal to a third threshold S3 lower than the second threshold S2, and comprising a first substantially linearly increasing portion according to a third slope P3 less than the second slope P2, followed by a second portion substantially constant (herein equal to the maximum torque cm_{3 x}, although this is not mandatory) and itself followed by a third portion decreasing monotonic (herein equal to the third portion of the first torque profile C1, although this is not mandatory), and

-a fourth torque profile C4 (formed by a chain line points), associated with a fourth interval of distances vehicle-snag [...] strictly less than the third threshold S3 and greater than or equal to a fourth threshold S4 less than the third threshold S3, and comprising a first substantially linearly increasing portion according to a fourth slope P4 P3 less than the third slope, followed by a second portion decreasing monotonic (herein partially equal to the third portion of the first torque profile C1, although this may not be required).

It should be noted that in this first time evolution, as in that of Figure 3 described below, the reference tO designates the time when the driver ceases to act on the brake pedal and thus the time of the start of creep speed mode.

It has schematically shown in Figure 3, within a second pattern in temporal variation, four speed profiles C1 'to C4' associated respectively with the four profiles torque C1 to C4 of Figure 2.

In this example:

-the first speed profile C1 ' (formed by a continuous line) includes a first portion monotone increasing, followed by a second substantially linearly increasing portion. It corresponds to first speeds V1 adapted to O or absence of an obstacle to the presence of an obstacle O very remote from the vehicle V (typically [...] > 10 metres and < 12 km/h V1),

-the second velocity profile C2 '(formed by a chain line) includes a first portion monotone increasing (located substantially completely below the first portion of the first velocity profile C1'), followed by a second substantially linearly increasing portion. It corresponds to second speed V2 lower than the first speed V1 and adapted to the presence of an obstacle O relatively remote from the vehicle V (typically [...] > 5 metres and [...] < 10 metres and V2 < 10 km/h),

-the third velocity profile C3 '(formed by a dotted line) includes a first portion monotone increasing (located substantially completely below the first portion of the second velocity profile C2'), followed by a second substantially linearly increasing portion. It corresponds to third speed lower than the second speed V2 V3 and adapted to the presence of an obstacle O medium remote from the vehicle V (typically [...] > 3 metres and [...] < 5 metres and V3 < 8 km/h),

the fourth velocity profile-C4 '(formed by a chain line points) includes a first portion monotone increasing (located substantially completely below the first portion of the third velocity profile C3'), followed by a second substantially linearly increasing portion. It corresponds to fourth speeds lower than the third speed V3 V4 and adapted to the presence of an obstacle O very little remote from the vehicle V (typically [...] < 3 metres and V4 < 5 km/h).

With a torque increase which is all the more gentle as vehicle-snag [...] the distance is small, the increase of vehicle speed V is slower than said distance vehicle-snag [...] is small, thus allowing the operator to better manage the approach phase 5 of the obstacle O and in particular have substantially does not have to actuate the accelerator pedal.

It should be noted that in an alternative embodiment the control means MC could be arranged to calculate the torque profile as a function of the distance vehicle-snag [...], rather than to select this profile [...] of torque among a plurality of predefined profiles torque.

The invention is improved since the driving pleasure and safety during tripping performed at low speed.