SIMPLIFIED CONTROL OF EMERGENCY STOPPING OF A LAND VEHICLE BY ACTIVATING A SPEED LIMITING FUNCTION

Abstract

A control method is implemented in a land vehicle and includes a powertrain designed to supply the drive wheels with torque according to a torque setpoint, a speed-limiting function designed, when activated, to generate a torque setpoint enabling the vehicle not to exceed a speed setpoint, and an emergency stop function designed, when a significant event is detected, to order the vehicle to stop. This method includes a step (10-30) in which, if a stop is ordered while the vehicle is traveling at a non-zero speed, the speed-limiting function is provided with at least one main speed setpoint strictly lower than the vehicle speed so that it generates at least one negative torque setpoint designed to reduce the vehicle speed. Figure 3

Description

Title of the invention: SIMPLIFIED CONTROL OF THE EMERGENCY STOP OF A LAND VEHICLE BY ACTION OF A SPEED LIMITING FUNCTION Technical field of the invention

[0001] The invention relates to land vehicles comprising an emergency stop function capable of ordering their stopping in the event of detection of a significant event, and more precisely the control of this stopping. State of the art

[0002] Certain land vehicles, possibly of the automobile type, comprise:

[0003] - a powertrain (or GMP) capable of providing their drive wheels with a torque which is a function of a torque setpoint, and

[0004] - an emergency stop function (sometimes called "safe stop" in English), in case of detection of a significant event (such as for example a lack of vigilance of the driver), to order a stop of the vehicle (possibly after having triggered a series of alerts (audible and / or visual and / or haptic).

[0005] Currently, when a stop is ordered by the emergency stop function, the GMP supervision computer must manage on its own to stop the vehicle in an emergency. In particular, it must no longer take into account the driver pressing the accelerator pedal, and prevent the GMP from supplying positive torque to the drive wheels. It should be noted, however, that when the accelerator pedal is pressed to a predefined hard point (sometimes called "kick down"), the GMP supervision computer must allow the driver to regain control of the vehicle and must start taking into account the pressing of the accelerator pedal again.

[0006] Control of the emergency stop by the GMP supervision computer therefore requires the development of a new specific function in the latter, but such development proves to be expensive and time-consuming to carry out and validate.

[0007] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0008] For this purpose, it proposes in particular a control method intended to be implemented in a land vehicle and comprising:

[0009] - a powertrain suitable for providing drive wheels with a torque function of a torque instruction,

[0010] - a speed limitation function capable, when activated, of generating a torque instruction allowing the vehicle not to exceed a speed instruction, And

[0011] - a specific emergency stop function, in the event of detection of an event important, to order a stop of the vehicle.

[0012] This control method is characterized by the fact that it comprises a step in which, in the event of an ordered stop while the vehicle is traveling at a non-zero speed, the speed limitation function is provided with at least one main speed setpoint which is strictly lower than the speed of the vehicle so that it generates at least one negative torque setpoint capable of reducing this speed of the vehicle.

[0013] Thanks to the invention, the speed limitation function is now used with at least one main speed instruction to stop the vehicle, without this requiring adaptation of this speed limitation function, which does not require significant development and therefore proves to be particularly simple and economical to implement.

[0014] The control method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0015] - in its step, in the event of an ordered stop while the vehicle is traveling at a speed non-zero, the speed limitation function can be provided with a main speed setpoint which is zero so that it generates a negative torque setpoint capable of making the vehicle speed tend towards zero;

[0016] - in its step, one can initially provide the speed limitation function a preliminary speed setpoint which is higher than the vehicle speed, then the speed limitation function can be provided with the (each) main speed setpoint;

[0017] - in the presence of the last option, in its step, the speed instruction pre threshold may be between 101% of vehicle speed and 110% of vehicle speed;

[0018] - in its step, when the speed limitation function is deactivated at when the stop is ordered, this speed limitation function can be immediately activated;

[0019] - in its step, the speed limitation function can perform at least one filtering each generated negative torque setpoint so that it falls within a first chosen interval and / or has a variation within a second chosen interval;

[0020] - in the presence of the last option, in its step, the first interval can be chosen based on vehicle speed and / or the second interval can be chosen based on vehicle speed.

[0021] The invention also provides a computer program product comprising a set of instructions which, when executed by processing means, is capable of implement a control method of the type presented above, in a land vehicle and comprising, on the one hand, a powertrain capable of providing drive wheels with a torque depending on a torque setpoint, on the other hand, a speed limitation function capable, in the event of activation, of generating a torque setpoint allowing the vehicle not to exceed a speed setpoint, and, on the other hand, an emergency stop function capable, in the event of detection of a significant event, of ordering a stop of the latter, to control an emergency stop of the vehicle in the event of an ordered stop.

[0022] The invention also proposes a control device intended to equip a land vehicle and comprising:

[0023] - a powertrain suitable for providing drive wheels with a torque function of a torque instruction,

[0024] - a speed limitation function capable, when activated, of generating a torque setpoint allowing the vehicle not to exceed a speed setpoint, and

[0025] - a specific emergency stop function, in the event of detection of an event important, to order a stop of the vehicle.

[0026] This control device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting, in the event of an ordered stop while the vehicle is traveling at a non-zero speed, in providing the speed limitation function with at least one main speed setpoint which is strictly lower than the speed of the vehicle so that it generates at least one negative torque setpoint capable of reducing this speed of the vehicle.

[0027] The invention also proposes a land vehicle, possibly of the automobile type, and comprising:

[0028] - a powertrain suitable for providing drive wheels with a torque function of a torque instruction,

[0029] - a speed limitation function capable, when activated, of generating a torque setpoint allowing the vehicle not to exceed a speed setpoint,

[0030] - a specific emergency stop function, in the event of detection of an event important, to order a stop of the vehicle, and

[0031] - a control device of the type presented above. Brief description of the figures

[0032] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0033] [Fig-1] schematically and functionally illustrates an example of the embodiment of a land vehicle including a thermal GMP, a supervision computer, a speed limit calculator, an emergency stop calculator, and a control device according to the invention,

[0034] [Fig.2] schematically and functionally illustrates an exemplary embodiment of an emergency stop calculator comprising an exemplary embodiment of a control device according to the invention, and

[0035] [Fig.3] schematically illustrates an example of an algorithm implementing a control method according to the invention. Detailed description of the invention

[0036] The invention aims in particular to propose a control method, and an associated control device DC2, intended to allow simplified control of the emergency stop of a land vehicle V when an emergency stop function FAU of the latter (V) has ordered a stop.

[0037] In the following, it is considered, by way of non-limiting example, that the land vehicle V is of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of land vehicle. It in fact relates to any type of land vehicle comprising a powertrain (or GMP), an emergency stop function and a speed limitation function.

[0038] [Fig.l] schematically shows a (land) vehicle V comprising a GMP transmission chain with a thermal motor MMT and a coupling device DC1 associated with an automated gearbox BV, a supervision computer CS, a speed limitation computer CL, an emergency stop computer CA, and a control device DC2 according to the invention.

[0039] It should be noted that the GMP could also be of the hybrid type (electric and thermal) or all-electric or even hydrogen. Furthermore, the transmission chain could also allow a four-wheel drive mode (or 4x4) or 4x2.

[0040] As illustrated, the transmission chain also comprises, here, an AM drive shaft and an AT transmission shaft.

[0041] The operation of the transmission chain (and therefore of the GMP) is supervised by the supervision computer CS.

[0042] The GMP being here purely thermal, as an illustrative example, it comprises a thermal motor MMT comprising a crankshaft (not shown) which is fixedly secured to the engine shaft AM in order to drive the latter (AM) in rotation. This thermal motor MMT is capable of operating according to a speed to provide a first torque, on order of the supervision computer CS. In addition, it (MMT) is capable of being coupled to the primary shaft AP of the gearbox BV (automated) via the coupling device DC1. The latter (DC1) is capable of delivering for the gearbox BV a second torque from the first torque produced by the thermal motor MMT. The gearbox BV is capable of delivering a third torque from the second torque delivered by the coupling device DC1, in particular for at least one train T1 of driving wheels. This third torque (supplied to the driving wheels) is defined by a torque setpoint cc, which will be discussed later.

[0043] For example, the coupling device DC1 may be a clutch. But in an alternative embodiment it could be a torque converter.

[0044] Also for example, the train T1 can be located in the front part PVV of the vehicle V. It is preferably, and as illustrated, coupled to the transmission shaft AT via a differential (here front) DV. But in a variant this train T1 could be that referenced T2 which is located in the rear part PRV of the vehicle V.

[0045] The speed limitation calculator CL provides at least one speed limitation function FLV within the vehicle V. This speed limitation function FLV is capable, in the event of activation, of generating a torque setpoint cc allowing the vehicle V not to exceed a speed setpoint cv. This generated torque setpoint cc is then transmitted to the supervision calculator CS.

[0046] It will be noted that the speed limitation calculator CL and the supervision calculator CS can, for example, communicate via an internal communication network RC of the vehicle V, possibly multiplexed, as illustrated non-limitingly in [Fig.l].

[0047] The emergency stop computer CA provides an emergency stop function FAU (sometimes called "safe stop" in English) which, in the event of detection of a significant event (such as, for example (and not limited to), a lack of vigilance on the part of the driver), orders a stop of the vehicle V (possibly after triggering a series of alerts (audible and / or visual and / or haptic).

[0048] It will be noted that the emergency stop computer CA and the supervision computer CS can, for example, communicate via the internal communication network RC, as illustrated non-limitingly in [Fig.l].

[0049] As mentioned above, the invention proposes in particular a control method intended to allow simplified control of the emergency stop of the vehicle V when the emergency stop function FAU has ordered a stop.

[0050] This (control) method can be implemented at least partially by the control device DC2 (illustrated at least partially in FIGS. 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This control device DC2 can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller. It will be noted, as we will see later, that part of the process can also be implemented by the speed limitation function FLV, here controlled by the speed limitation calculator CL.

[0051] The memory MD is RAM in order to store instructions for the implementation by the processor PR1 of at least part of the control method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0052] In the example illustrated non-limitingly in Figures 1 and 2, the control device DC2 is part of the emergency stop computer CA. But this is not obligatory. Indeed, the control device DC2 could comprise its own dedicated computer, which is then coupled to the emergency stop computer CA, or could be part of another computer on board the vehicle V and providing at least one other function, such as for example the speed limit computer CL or the supervision computer CS.

[0053] As illustrated non-limitingly in [Fig. 3], the (control) method, according to the invention, comprises a step 10-30 which is implemented each time that the vehicle V is in a movement phase (with a non-zero speed vv) and therefore that its GMP provides torque.

[0054] Step 10-30 of the method comprises a sub-step 20 in which, in the event of a stop ordered by the emergency stop function FAU while the vehicle V is traveling at a non-zero speed vv, the control device DC2 (for example) provides the speed limitation function FLV with at least one main speed setpoint cvpl which is strictly lower than this speed vv of the vehicle V. This (each) main speed setpoint cvpl is determined so that the speed limitation function FLV generates at least one negative torque setpoint cc capable of reducing the speed vv of the vehicle V. It will be understood that, since the main speed setpoint cvpl is strictly lower than the speed vv of the vehicle V, the speed limitation function FLV is obliged to generate a negative torque setpoint cc.

[0055] Thus, the speed limitation function FLV is used very advantageously by requiring it to use at least one main speed instruction cvpl to stop the vehicle V, without this requiring adaptation of this speed limitation function FLV. Admittedly, this requires designing the control device DC2, but this design is particularly simple and very inexpensive because the latter (DC2) essentially needs to deliver each main speed instruction cvpl for the speed limitation function FLV when it receives the stop order generated by the emergency stop function FAU.

[0056] It will be noted that the speed limitation function FLV also advantageously makes it possible, by design, to discriminate the situation in which the accelerator pedal of the vehicle V is pressed down to a predefined hard point (sometimes called "kick down" in English). Consequently, the invention also makes it possible to guarantee that in the aforementioned situation the driver of the vehicle V can regain control of the latter (V) and that the supervision computer CS can start taking into account the pressing of the accelerator pedal of the vehicle V again.

[0057] For example, in sub-step 20 of step 10-30, in the event of an ordered stop while the vehicle V is traveling at a non-zero speed vv, one (for example the control device DC2) can provide the speed limitation function FLV with a main speed setpoint cvpl which is zero (i.e. cvpl = 0 km / h). This zero main speed setpoint cvpl imposes on the speed limitation function FLV a generation of a negative torque setpoint cc capable of making the speed vv of the vehicle V tend towards zero.

[0058] But other embodiments can be envisaged. Thus, one (for example the control device DC2) can, for example, provide the speed limitation function FLV with a first main speed setpoint cvpl which is strictly lower than the speed vv of the vehicle V and not zero, then a second main speed setpoint cvpl which is zero. Alternatively, one (for example the control device DC2) can, for example, provide the speed limitation function FLV with main speed setpoints cvpl which decrease while all being strictly lower than the speed vv of the vehicle V until reaching the zero value.

[0059] Also for example, and as illustrated non-limitingly in [Fig. 3], step 10-30 of the method may also comprise a sub-step 10 in which one (for example the control device DC2) may initially provide the speed limitation function FLV with a preliminary speed setpoint cvp2 which is greater than the speed vv of the vehicle V. In this case, one (for example the control device DC2) then provides the speed limitation function FLV with each main speed setpoint cvpl in sub-step 20.

[0060] This option is intended to prevent the activation of the FLV speed limitation function by the control device DC2 from occurring with a speed vv of the vehicle V which is higher than this first speed instruction, in the event of acceleration of the vehicle V at the time when the stop is ordered and even though the speed limitation function FLV has been previously deactivated with a first speed instruction, and therefore causing the resumption of operation of the FLV speed limitation function with this first speed instruction. It will be understood that by imposing on the FLV speed limitation function a preliminary speed instruction cvp2 higher than the speed vv of the vehicle V, its activation is certainly caused but not its resume with the first speed instruction (strictly lower than this preliminary speed instruction cvp2).

[0061] Also for example, in sub-step 10 the preliminary speed setpoint cvp2 can be between 101% of the speed vv of the vehicle V and 110% of the speed vv of the vehicle V. As an illustrative example, the preliminary speed setpoint cvp2 can be equal to 110% of the speed vv of the vehicle V. But other values ​​can be envisaged.

[0062] Preferably, the time interval between the provision of the preliminary cvp2 and main cvpl speed instructions is very small. For example, it may be between 50 ms and 200 ms. As an illustrative example, this time interval may be equal to 100 ms. But other values ​​may be envisaged. A very small value is intended to very quickly stop the provision of a third positive torque to the drive wheels by the GMP.

[0063] It will be noted that the longitudinal dynamics of the vehicle V are ensured, in addition to the GMP, by other systems on board the vehicle V, such as for example the braking system.

[0064] It will also be noted that in step 10-30, when the speed limitation function FLV is deactivated at the time when the stop is ordered by the emergency stop function FAU, one (for example the control device DC2) can immediately activate this speed limitation function FLV before imposing on it the use of a main speed setpoint cvpl or preliminary speed setpoint cvp2. In this case the activation takes place at the start of sub-step 10. But it can also be envisaged that the mere fact of providing a main speed setpoint cvpl or preliminary speed setpoint cvp2 makes it possible to activate this speed limitation function FLV.

[0065] Also for example, and as illustrated non-limitingly in [Fig.3], step 10-30 of the method may also comprise a sub-step 30 in which the speed limitation function FLV may perform at least one filtering of each negative DC torque setpoint that it generates so that it is included in a first chosen interval and / or has a variation included in a second chosen interval. The first interval is sometimes called an acceleration template (in m / s2). The second interval is sometimes called an acceleration variation template (or “jerk”) (in m / s3).

[0066] For example, the first interval can be chosen as a function of the speed vv of the vehicle V and / or the second interval can be chosen as a function of the speed vv of the vehicle V. It can also optionally be chosen as a function of the difference between the speed of the vehicle V (vv) and the main speed setpoint cvpl or preliminary speed setpoint cvp2. But this is not obligatory, and in this case the first interval has fixed (non-variable) limits and / or the second interval has fixed (non-variable) limits.

[0067] It will also be noted, as illustrated non-limitingly in [Fig.2], that the callus The emergency stop computer CA (or the computer of the control device DC2) may also comprise a mass memory MM1, in particular for storing the speed vv of the vehicle V, as well as any intermediate data involved in all its calculations and processing. Furthermore, this emergency stop computer CA (or the computer of the control device DC2) may also comprise an input interface IE for receiving at least the stop command and the speed vv of the vehicle V, possibly after having formatted and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2. In addition, this emergency stop computer CA (or the computer of the control device DC2) may also comprise an output interface IS, in particular for delivering each message containing a main speed instruction cvpl or preliminary cvp2 and / or a possible activation command.

[0068] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1 and possibly the speed limitation calculator CL, is capable of implementing the control method described above to control an emergency stop of the vehicle V in the event of a stop ordered by the emergency stop function FAU.

Claims

Claims

1. Control method for a land vehicle (V) and comprising i) a powertrain capable of supplying to drive wheels a torque as a function of a torque setpoint, ii) a speed limitation function capable, in the event of activation, of generating a torque setpoint allowing said vehicle (V) not to exceed a speed setpoint, and iii) an emergency stop function capable, in the event of detection of a significant event, of ordering a stop of said vehicle (V), characterized in that it comprises a step (10-30) in which, in the event of an ordered stop while said vehicle (V) is traveling at a non-zero speed, said speed limitation function is supplied with at least one main speed setpoint strictly lower than said speed of the vehicle (V) so that it generates at least one negative torque setpoint capable of reducing said speed of the vehicle (V).

2. Method according to claim 1, characterized in that in said step (10-30), in the event of an ordered stop while said vehicle (V) is traveling at a non-zero speed, said speed limitation function is provided with a zero main speed setpoint so that it generates a negative torque setpoint capable of causing said vehicle speed (V) to tend towards zero.

3. Method according to claim 1 or 2, characterized in that in said step (10-30) said speed limitation function is initially provided with a preliminary speed setpoint greater than said vehicle speed (V), then each main speed setpoint is provided to said speed limitation function.

4. Method according to claim 3, characterized in that in said step (10-30) said preliminary speed setpoint is between 101% of said vehicle speed (V) and 110% of said vehicle speed (V).

5. Method according to one of claims 1 to 4, characterized in that in said step (10-30), when said speed limitation function is deactivated at the time when said stop is ordered, this speed limitation function is immediately activated.

6. Method according to one of claims 1 to 5, characterized in that in said step (10-30) said speed limitation function carries out at least one filtration of each negative torque setpoint generated so that it is included in a first chosen interval and / or presents a variation included in a second chosen interval.

7. Method according to claim 6, characterized in that in said step (10-30) said first interval is chosen as a function of said vehicle speed (V) and / or said second interval is chosen as a function of said vehicle speed (V).

8. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the control method according to one of claims 1 to 7, in a land vehicle (V) and comprising i) a powertrain capable of providing drive wheels with a torque depending on a torque setpoint, ii) a speed limitation function capable, in the event of activation, of generating a torque setpoint allowing said vehicle (V) not to exceed a speed setpoint, and iii) an emergency stop function capable, in the event of detection of a significant event, of ordering a stop of said vehicle (V), to control an emergency stop of said vehicle (V) in the event of an ordered stop.

9. Control device (DC2) for a land vehicle (V) and comprising i) a powertrain capable of supplying to drive wheels a torque as a function of a torque setpoint, ii) a speed limitation function capable, in the event of activation, of generating a torque setpoint allowing said vehicle (V) not to exceed a speed setpoint, and iii) an emergency stop function capable, in the event of detection of a significant event, of ordering a stop of said vehicle (V), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting, in the event of an ordered stop while said vehicle (V) is traveling at a non-zero speed,to provide said speed limitation function with at least one main speed setpoint strictly lower than said vehicle speed (V) so that it generates at least one negative torque setpoint capable of reducing said vehicle speed (V).,

10. Land vehicle (V) comprising i) a powertrain capable of supplying drive wheels with torque as a function of a torque setpoint, ii) a speed limitation function capable, in the event of activation, of generating a torque setpoint allowing said vehicle (V) not to exceed a speed setpoint, and iii) an emergency stop function capable, in the event of detection of a significant event, of ordering a stop of said vehicle (V), characterized in that it comprises further a control device (DC2) according to claim 9.

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