EP3554906A1

EP3554906A1 - Speed control for a vehicle

Info

Publication number: EP3554906A1
Application number: EP17817783.8A
Authority: EP
Inventors: Alexandre BLANCHET; Valentina CIARLA; Xavier DUBOURG; Simon MICHAUT
Original assignee: PSA Automobiles SA
Current assignee: Stellantis Auto SAS
Priority date: 2016-12-16
Filing date: 2017-11-23
Publication date: 2019-10-23
Also published as: FR3060482B1; FR3060482A1; CN110087961A; WO2018109300A1

Abstract

A method for controlling the speed of a vehicle equipped with an automatic deceleration function receiving at least first and second maximum deceleration setpoints of the vehicle that can be selected by the driver, the vehicle being further equipped with a driver assistance system using the automatic deceleration function to control a deceleration in order to maintain a speed setpoint of the vehicle. The method comprises a first step consisting of limiting a deceleration control of the driver assistance system to a maximum deceleration setpoint selected by the driver from among the first and second maximum deceleration setpoints, then, in case of vehicle overspeed (205) and in the absence of an acceleration request from the driver (206), a second step consisting of limiting the deceleration control of the driver assistance system to a value less than or equal to the second maximum deceleration setpoint.

Description

SPEED CONTROL OF A VEHICLE

The invention relates to a method of regulating the speed of a vehicle during deceleration phases of the vehicle. The invention aims including, but not limited to, applications in the field of motor vehicles.

In this field, it is known to use speed control methods, said pace controllers, which, from a speed setpoint given by the driver, regulate the speed of the vehicle around this setpoint without the driver having to operate a brake or accelerator pedal, an action on the brake pedal automatically disabling the speed regulator.

[0004] It is also known that a driver can select a deceleration level that is automatically applied during the foot-lift of the accelerator pedal. In the case of the foot survey while the speed controller is activated, this regulator then takes as deceleration maximum setpoint the deceleration level previously chosen by the driver, but which is not always adapted to the situation encountered by the driver. pace regulator.

In particular, when the speed controller is activated, and after pressing the accelerator pedal for an overtaking or when the vehicle is in a steep downward slope, the vehicle is overspeeded relative to the speed setpoint, and must quickly return to its set speed to respect the will of the driver, and not give him a feeling of discomfort or insecurity due to lack of reactivity of the vehicle, in a situation that can be a configuration of 'emergency.

Patent document FR-A-2 839 284 discloses a method and a device for regulating the speed of a motor vehicle and a control element allowing a better prescription, by the driver of the vehicle, of the acceleration and / or deceleration. For this, the speed regulation is effected according to a value of acceleration and / or deceleration of the vehicle, prescribed by means of the control element, the function of which is different from that of a pedal. acceleration or brake. By operating the control element, one of several acceleration and / or deceleration values is selected. The solution of this patent document FR-A-2,839,284 has the advantage of being able to change the acceleration or deceleration and thus adapt the speed regulation process to a situation, but this requires the intervention. the driver: either by actuating the brakes causing the deactivation of the speed regulation process, or by actuation of the control element, which induces a delay which is a function of the reflex of the driver and penalizes the reactivity of the vehicle, this being particularly troublesome in emergency situation. In addition, this intervention of the driver is uncomfortable and the distraction of his conduct.

The object of the invention is to overcome this disadvantage, in particular by optimizing a method of regulating the speed of a vehicle.

For this purpose, the subject of the invention is a method for controlling the speed of a vehicle equipped with an automatic deceleration function having at least a first and a second operating mode respectively corresponding to a first and a second a second set of maximum deceleration of the vehicle that can be selected by the driver, the first maximum deceleration setpoint being lower than the second maximum deceleration setpoint. The vehicle is also equipped with a driving aid using the automatic deceleration function to control a deceleration to maintain the vehicle at a set speed. The method then comprises a first step consisting in limiting a deceleration control of the driving aid to a maximum deceleration setpoint selected by the driver from the first and second maximum deceleration setpoints, and then, in the event of an overspeed of the vehicle, and in the absence of a driver acceleration request, a second step of limiting the deceleration control of the driving aid to a value less than or equal to the second maximum deceleration limit.

Thus, this method automatically authorizes, and without the knowledge of the driver, the deceleration control of the driver assistance most suited to the vehicle situation, without surprising the driver since this authorization remains limited to the second setpoint of maximum deceleration, second setpoint which is already a possible choice by the driver for the automatic deceleration function.

[001 1] The driver has no intervention to do and therefore, the driving aid remains active. In particular, in case of inadvertent overspeed, as after a overtaking or in a descent, the driver no longer needs to depress a brake pedal, an action that would deactivate the driving aid.

It will be understood by active driving assistance, throughout the text of this document, a driving aid selected by the driver but which is without action. The driving aid deactivated requires a second selection of the driver to become active again.

[0013] It will be understood by effective driving assistance, throughout the text of this document, a driving aid selected by the driver and acting by driving, for example, the automatic deceleration function via the control in deceleration.

It will be understood throughout the text of this document by automatic deceleration function, a function that coordinates deceleration devices to meet a predetermined deceleration setpoint, for example following a foot lift of the accelerator, or to meet a deceleration setpoint determined by another function.

In one embodiment, when the automatic deceleration function has at least three operating modes corresponding to three maximum deceleration instructions of the vehicle, the second step consists in limiting the deceleration control of the driving aid to the vehicle. a maximum deceleration setpoint less than or equal to the highest maximum deceleration setpoint.

Indeed, the driving aid is thus ensured to be able to apply, if necessary, the deceleration control to the value of the highest maximum deceleration setpoint among the maximum deceleration instructions selectable by the driver, this which allows a rapid convergence of the speed of the vehicle towards the speed of reference, and thus a time in reduced overspeed.

In an alternative embodiment, the second step consists in setting the deceleration control of the driving aid to the value of the second maximum deceleration setpoint.

Thus the method allows the fastest convergence of the vehicle speed to the target speed, and therefore a time in the most reduced overspeed. In an alternative embodiment, the second step consists in determining the value of the control during deceleration of the driving aid as a function of a foot lift gradient of an accelerator pedal following an acceleration. of the vehicle. Indeed, this foot lift gradient of an accelerator pedal is representative of a reactivity of the method expected by the driver. The higher the gradient, the more the value of the deceleration control will approach the second maximum deceleration setting.

In one embodiment, the automatic deceleration function furthermore has a regenerative braking mode, and once the second stage has been completed, the speed control method comprises a third step consisting, for the driving aid, controlling the regenerative braking mode with the automatic deceleration function to comply with the deceleration control of the driving aid as soon as the state of charge of a corresponding energy store the vehicle is less than 100%.

Indeed, the second maximum deceleration setting may not be selectable by the driver if the state of charge of the energy store does not allow a minimum energy recovery. It is therefore advantageous, so as to optimize the energy saving, but also to have the fastest convergence of the vehicle speed to the set speed, the first action of the automatic deceleration function requested by the driving aid is regenerative braking.

In one embodiment, the vehicle comprises a reversible electric propulsion motor, and the automatic deceleration function controls the electric motor to achieve the regenerative braking mode.

In one embodiment, the vehicle is a hybrid vehicle comprising at least one friction brake and a propulsion engine capable of producing a braking torque of the vehicle, so that to respect the deceleration control of the vehicle. driving aid, and in addition to, or in substitution for, the regenerative braking mode if the state of charge of the energy store is equal to 100%, the automatic deceleration function controls in respective order of priority: [0025] a) the braking torque of the heat engine, [0026] b) the braking torque of the brake by friction.

In one embodiment, the return to the first step is performed as soon as a sub-speed or action of the driver on a brake control is detected. In one embodiment, the driving aid is a speed limitation, a speed control, an assistant parking maneuver, or a distance control between vehicles.

The invention also relates to a vehicle comprising a computer, the computer having a memory containing a set of instructions implementing the steps of the method as briefly described above.

Other features, objects and advantages of the invention will become apparent on reading the description of the nonlimiting exemplary embodiments which will follow, with reference to the appended FIGS. 1 to 3, which represent:

[0031] - Figure 1: an architecture of the method according to a particular embodiment of the invention.

[0032] - Figure 2: a logic diagram of the steps according to a particular embodiment of the invention.

[0033] - Figure 3: a timing diagram of the method according to a particular embodiment of the invention. The assembly shown in Figure 1 shows the architecture of a method according to a particular embodiment, not limiting, of the invention.

This speed control method applies to a vehicle equipped with an automatic deceleration function 101 which has at least a first and a second mode of operation 102, 103 respectively corresponding to a first and a second set of instructions. of maximum deceleration 201, 202 of the vehicle that can be selected by the driver. The first maximum deceleration setpoint 201 is lower than the second maximum deceleration setpoint 202. The vehicle is further equipped with a driving aid 104 using the automatic deceleration function 101 to control a deceleration to maintain the vehicle at a set speed 203, without intervention of the driver.

This method comprises a first step 10 (see FIG. 2) of limiting a deceleration control 204 of the driving aid 104 to a maximum deceleration setpoint selected by the driver from among the first and second maximum deceleration instructions. 201, 202, then, in the event of the vehicle being overspeeded and in the absence of a request for acceleration of the conductor 206, a second step 20 (see FIG. 2) consists in limiting the deceleration control 204 of the assistance to the vehicle. pipe 104 at a value less than or equal to the second maximum deceleration setting 202.

By way of example, the first maximum deceleration setting 201 is of the order of 0.2 m / s ² , while the second maximum deceleration setting 202 is of the order of 1 m / s. ² . The driving aid 104 is advantageously a cruise control. Alternatively, the driving aid may be a speed limit, an assistant parking maneuver, or a distance control between vehicles.

In an alternative embodiment, the second step 20 (see Figure 2) is to set the deceleration control 204 of the driving aid 104 to the value of the second maximum deceleration setting 202. Whatever the selection of the driver, this second maximum deceleration setpoint 202 is prioritized and becomes the deceleration control 204.

In an alternative embodiment, not shown, when the automatic deceleration function 101 has at least three operating modes corresponding to three maximum deceleration instructions of the vehicle, the second step 20 then consists in limiting the deceleration control 204 of the driving aid 104 at a maximum deceleration setpoint less than or equal to the highest of the maximum deceleration setpoints, which makes it possible, whatever the situation, to ensure a fast return to the set speed. In another variant embodiment, not shown, the second step 20 consists in determining the value of the deceleration control 204 of the aid to the driving 104 according to a foot lift gradient of an accelerator pedal 207 following an acceleration of the vehicle.

This foot lift gradient of an accelerator pedal 207 is representative of a reactivity of the method expected by the driver. If the gradient is low, it means that the driver slowly raises his foot, either because he hesitates to brake, or because he considers the engine brake sufficient compared to the situation of the vehicle. In this case, the driver will expect to have a low engine brake, of the order of 0.5 m / s ² .

By motor brake is meant throughout the text of this document, the mechanical resistance opposing the advancement of the vehicle, but also any method reproducing or amplifying this mechanical strength when it is insufficient, thus including speed control method. For example, the engine brake includes the internal friction of a transmission, the wheels on the road, the internal friction of a heat engine and its losses by pumping if it is rotated, the internal friction of an electric motor and / or its resistive torque if it is driven in current generator mode to simulate the engine brake, the resistance to the advancement of air, these examples not being limiting.

Conversely, if the gradient is strong, it means that the driver gets up quickly from the accelerator, either because he needs to brake quickly, or because an external event surprises him. In this case, the driver will expect to have or wish to have a stronger engine brake, without it being comparable to a voluntary braking action which could surprise the driver if he did not want action on the brake. For this stronger engine brake, a deceleration of the order of 1 m / s ² will be retained. So as not to surprise the driver if he did not want action on the brake, in this variant as in other cases, the deceleration control 204 of the driving aid 104 is limited to a lower value or equal to the second maximum deceleration setting 202 or the highest maximum deceleration setpoint, which are already predefined setpoints in the operating modes of the automatic deceleration function 101.

In an alternative embodiment, the foot lift gradient of an accelerator pedal 207 is replaced by a driving mode selected by the driver, such as a sport mode corresponding to a high equivalent gradient, or an economical mode corresponding to a weak equivalent gradient. In an alternative embodiment, the foot lift gradient of an accelerator pedal 207 is replaced by a sportivity index depending on the behavior of the driver.

In a variant, the foot lift gradient of an accelerator pedal 207, or the equivalent gradient, are weighted by a coefficient which is a function of the value of a vehicle slope detection, or of detecting the vehicle load, or detecting the speed of the vehicle, or a combination of these detections.

In one embodiment, and still in connection with FIG. 1, the automatic deceleration function 101 also has a regenerative braking mode 105. This regenerative braking 105 can, by for example, be a kinetic energy recovery system, this energy being stored in a flywheel-type energy store, or a compressed air tank, a pressurized hydraulic tank, or a battery. This regenerative braking can more particularly be a current generator driven by the inertia of the vehicle. Once the second step 20 (see FIG. 2) has been performed, the speed control method comprises a third step consisting, for the driving aid 104, in controlling the automatic deceleration function 101 to regenerative braking 105 to comply with the deceleration command 204 of the driver assistance 104 as soon as the state of charge of the corresponding energy storage of the vehicle is less than 100%. This is a way of prioritizing regenerative braking 105. This prioritization is symbolized by the dashed line of FIG. 1, connecting step 30 to the regenerative braking mode 105, passing through the automatic deceleration function 101. Indeed, the driving aid 104 imposes the regenerative braking mode 105, but this regenerative braking mode 105 can be controlled outside the action of the driving aid. 104. For example, when the driver actuates the brake pedal, the driving aid 104 is deactivated, but the automatic deceleration function 101 takes over and controls the regenerative braking mode 105 which is not then more limited by the second maximum deceleration setting 202. In one embodiment, the vehicle comprises a reversible electric propulsion motor, and the automatic deceleration function 101 controls the electric motor to achieve the regenerative braking mode. 105. In addition, the vehicle is a hybrid vehicle comprising at least one friction brake and a a propulsion thermal engine capable of producing a braking torque 106, 107 of the vehicle and, in order to respect the deceleration control 204 of the driving aid 104, and in addition, or in substitution with the regenerative braking mode If the state of charge of said energy store is equal to 100%, the automatic deceleration function 101 controls in respective order of priority:

[0052] the braking torque of the heat engine 106,

The braking torque of the friction brake 107.

Thus, if the regenerative braking mode 105 is not sufficient to respect the deceleration control 204 of the driving aid 104, or if the state of charge of the energy store is equal to 100%, the automatic deceleration function 101 controls other braking means starting with the means not causing the use of wearing parts, such as the braking torque of the heat engine 106 by pumping air. This engine is then driven, according to a known prior art, without fuel injection and playing on an air metering and / or playing on the adjustment of the valves and / or on an exhaust brake. At this braking torque of the heat engine 106, can be added any torque from accessories of the engine, such as an air conditioning compressor for example. Other types of braking that do not use wearing parts, such as induction (or electromechanical) braking using eddy current through discs, can also be considered. If, despite this, the deceleration control 204 of the driving aid 104 can not be respected, for example in the event of a strong descent of the road, then the automatic deceleration function 101 controls, in addition, the braking torque of the friction brake 107, generally consisting of discs or brake drums associated with brake linings, on each wheel of the vehicle, which are then wear parts. It will be noted that the friction brake 107 thus controlled does not deactivate the driving aid 104.

FIG. 2 represents a logic diagram of the steps of the method according to one embodiment of the invention. Y is the first step 10, of limiting the deceleration control 204 of the driving aid 104 to a maximum deceleration set selected by the driver among the first and second maximum deceleration instructions 201, 202. It also shows the transition for the second step 20, corresponding to the case of overspeed 205 of the vehicle and in the absence of driver acceleration request 206.

The overspeed corresponds, of course, and throughout the text of this document, at an instantaneous speed of the vehicle which is greater than the set speed that must maintain the driving aid 104.

The lack of driver acceleration request 206 corresponds throughout the text of this document, the fact that the driver does not actuate any acceleration command, whether it is an accelerator pedal, a steering wheel control , or lever or joystick on the dashboard, having an instantaneous action on the acceleration of the vehicle. The selection of operating modes is therefore not a brake control action.

It shows the second step 20 which consists in limiting the deceleration control 204 of the driving aid 104, as well as the third step 30 of controlling the braking means as previously described. FIG. 2 mainly illustrates the return to the first step 10, which is performed, whatever the current step, as soon as a sub-speed 208 or an action of the driver 209 on a brake control is detected. . When the action of the driver 209 on a brake control is detected, the latter deactivates the driving aid 104 and, in fact, to return to the first step 10, the driver will have to reactivate (action not represented) the aid to the line 104, while in the case of the sub-speed 208, the return to the first step 10 is automatic, because the driving aid 104 is still active.

The sub-speed 208 corresponds, throughout the text of this document, to an instantaneous speed of the vehicle which is less than the set speed that must maintain the driving aid 104. The assembly shown in Figure 3 is a timing diagram of the method according to a particular embodiment of the invention, comprising two graphics. This embodiment corresponds to the case where the second step 20 consists in setting the deceleration control 204 of the driving aid 104 to the value of the second maximum deceleration setting 202, the driving aid being a regulator of speed. The abscissa axes represent the same time for the two graphs. The ordinate axis for the top graph represents the corresponding 0 or 1 bit states:

For curve C5:

1 = selection by the driver of the second maximum deceleration setting 202 0 = selection by the driver of the first maximum deceleration setpoint 201 [0066] For curve C4:

1 = deceleration control 204 of the driving aid 104 active and effective set on the second maximum deceleration setpoint 202

0 = driving assistance 104 active but not effective. For curve C3 corresponding to mode 101, 102 in progress:

1 = second mode 103 corresponding to the second maximum deceleration setpoint 202

0 = first mode 102 corresponding to the first maximum deceleration setting 201 [0068] The ordinate axis for the bottom graph is the instantaneous vehicle speed for curve C2, and the set speed for curve C1.

It can be seen that at time t1, although the driver's choice is for the first maximum deceleration setpoint 201, the overspeed 205 being detected, the driving aid 104 takes hold, becomes effective and imposes the deceleration control 204 of the driving aid 104 fixed on the second maximum deceleration setting 202. The overspeed 205 will then be gradually reduced to converge to the set speed until the moment t2 where, a sub -speed being detected, the driving aid 104 remains active but is no longer effective, leaving the automatic deceleration function back to its first mode 102 corresponding to the first maximum deceleration setpoint 201. It can also be seen that the curve C3 corresponding to the current mode 101, 102 changes mode at time t1 and t2 without the knowledge of the choice of the driver, which at time 0 was on the second mode 103.

Claims

claims

A method of controlling the speed of a vehicle equipped with an automatic deceleration function (101) having at least first and second modes of operation (102, 103) respectively corresponding to first and second maximum deceleration instructions (201, 202) of said vehicle being selectable by the driver, said first maximum deceleration setting (201) being lower than said second maximum deceleration setting (202), said vehicle being further provided with a driving aid ( 104) using said automatic deceleration function (101) to control a deceleration to maintain said vehicle at a set speed (203), characterized in that said method comprises a first step (10) of limiting deceleration control ( 204) of said driving aid (104) to a maximum deceleration setpoint selected by the conductor one of said first and second setpoints of maximum deceleration (201, 202), then, in case of overspeed (205) of said vehicle and in the absence of driver acceleration request (206), a second step (20) consisting of limiting said deceleration control (204) of said driving aid (104) to a value less than or equal to said second maximum deceleration setpoint (202).

A method of controlling the speed of a vehicle according to claim 1, characterized in that when said automatic deceleration function (101) has at least three modes of operation corresponding to three maximum deceleration instructions of said vehicle, said second stage (20) ) comprises limiting said deceleration control (204) of said driving aid (104) to a maximum deceleration setpoint less than or equal to the highest of said maximum deceleration setpoints.

A method of controlling the speed of a vehicle according to claim 1, characterized in that said second step (20) comprises setting said deceleration control (204) of said driving aid (104) to the value of said second maximum deceleration setpoint (202).

A method of controlling the speed of a vehicle according to claim 1, characterized in that said second step (20) comprises determining the value of said deceleration control (204) of said driving aid (104) as a function of a gradient of lifting of an accelerator pedal (207) following an acceleration of said vehicle.

A method of controlling the speed of a vehicle according to one of the preceding claims, said automatic deceleration function (101) further having a regenerative braking mode (105), characterized in that once said second step (20) carried out, said speed control method comprises a third step (30) consisting, for said driving aid (104), in controlling said automatic deceleration function (101) with said regenerative braking mode. energy (105) to respect said deceleration control (204) of said driving aid (104) as soon as the state of charge of a corresponding energy store of said vehicle is less than 100%.

A speed control method of a vehicle according to claim 5, said vehicle comprising a reversible electric propulsion motor, characterized in that said automatic deceleration function (101) controls said electric motor to perform said regenerative braking mode. energy (105).

A method for controlling the speed of a vehicle according to claim 6, said vehicle being a hybrid vehicle comprising at least one friction brake and a propulsion engine capable of producing a braking torque (106, 107) of said vehicle, characterized in that, in order to comply with said deceleration control (204) of said driving aid (104), and in addition to, or in substitution with, said energy regenerative braking mode (105), if said load state of said storage storer energy is equal to 100%, said automatic deceleration function (101) controls in respective priority order: a. said braking torque of said heat engine (106), b. said braking torque of said friction brake (107).

A method of controlling the speed of a vehicle according to one of the preceding claims, characterized in that the return to said first step (10) is performed as soon as a sub-speed (208) or an action of the driver (209) ) on a brake control is detected.

A speed control method for a vehicle according to one of the preceding claims, characterized in that said driving aid (104) is a limitation of speed control, speed control, assistance with parking maneuvers, or distance control between vehicles.

10. Vehicle comprising a computer, characterized in that said computer comprises a memory containing a set of instructions implementing the steps of a method according to one of the preceding claims.