WO2020109681A1

WO2020109681A1 - Method for activating an autonomous urban electric braking mode

Info

Publication number: WO2020109681A1
Application number: PCT/FR2019/052387
Authority: WO
Inventors: Yannick BOTCHON; Mickael Mornet
Original assignee: Psa Automobiles Sa
Priority date: 2018-11-26
Filing date: 2019-10-09
Publication date: 2020-06-04
Also published as: FR3088878A1; FR3088878B1

Abstract

The invention concerns a method for activating, for an electric braking system, an autonomous urban braking mode, for a vehicle that comprises a set of electrical consumers (C1 to Cn; A1 to Am) of the sensor/actuator type and a control unit designed to control the electric braking system by using at least a portion of the electrical consumers, the vehicle also comprising control means designed to allow a user of the vehicle to request the control unit to switch to the autonomous urban braking mode, in which a first portion of the electrical consumers is to be activated specifically for the autonomous urban braking mode, such that the unit, in order to authorise the switch to the autonomous urban braking mode (71), uses an estimate of the electrical consumption (35) of the first portion of the electrical consumers to be activated specifically for the autonomous urban braking mode. Figure

Description

DESCRIPTION

METHOD OF ACTIVATING AN ELECTRIC BRAKING MODE

AUTONOMOUS URBAN

The present invention relates to a method for activating an urban electric braking mode.

The present invention relates mainly to an activation method for an electric braking system of an autonomous braking mode in city traffic, for a vehicle which comprises an electric power supply network which supplies an electric braking system and a set of consumers. electric type

sensors / actuators. The vehicle also comprising a control unit adapted to control the electric braking system using at least part of the

electrical consumers and control means adapted to allow a user of the vehicle to request the control unit to switch to said autonomous urban braking mode, a first part of the electrical consumers being to be activated specifically for the autonomous urban braking mode.

The automation of braking in urban traffic represents a real interest in terms of safety and comfort for the user, who is relieved of a heavy and tiring workload. Such a system consumes electrical energy because it uses numerous sensors and actuators. In addition, it generates safety issues that must be resolved, notably related to the management of the vehicle's autonomous braking (stop at traffic lights, compliance with safety distances with other vehicles, emergency stop, etc.). The proposed invention allows secure management of the electrical supply of an autonomous braking system, in urban traffic, while respecting the electrical constraints, linked to the supply of the on-board network of the vehicle and to the durability of the 12V battery. To do this, it is necessary that at all times the electric power available in the vehicle (via the alternator and the storage means) is sufficient to properly operate the urban autonomous electric braking system, including in case of use extreme. However, several electrical items of equipment, coupled to the electrical supply network (or on-board network), can consume electrical power at the time when the electrical braking system is requested, and therefore it may happen that the electrical power available in the vehicle do not be sufficient to satisfy all applicants at the same time. It can then happen that the autonomous urban electric braking system cannot be used in an optimal way, which can be dangerous.

As described in patent document EP-A2-1741607, it is possible to use storage means comprising a service battery and capacitors supplied by the latter and responsible for supplying the electric braking system in the event of failure of the by the service battery. However, when the electric braking system is heavily used at least twice in a short time, the capacitors cannot be recharged after the first application or at best do not have time to be fully recharged the second request, and no computer is informed.

It is also possible, as described in patent document EP-A1 -2570317, to provide two batteries redundantly, and one of them, unused, is always fully charged. Thus, when the battery in use cannot satisfy all the applicants at the same time, the other battery is used which is fully charged. But such redundancy is expensive and results in a significant increase in weight. In addition, this redundant mode of operation proves to be reactive and not anticipatory.

The object of the present invention is to overcome these problems and to propose an activation method for an electric braking system of an autonomous braking mode in city traffic, for a vehicle which comprises an electrical supply network which supplies a system braking system and a set of electrical consumers of the sensor / actuator type. The vehicle also includes a control unit adapted to control the electric braking system using at least some of the electrical consumers. The vehicle also includes control means adapted to allow a user of the vehicle to request the control unit to switch to said autonomous urban braking mode, a first part of the electrical consumers being to be activated specifically for the autonomous urban braking mode, such that the case, to authorize the passage into said autonomous urban braking mode, uses an estimate of the electrical consumption of the first part of the electrical consumers to activate specifically for said autonomous urban braking mode. According to a first characteristic of the invention, to allow passage into said mode, the box compares the electric power available in the vehicle with the electric power consumed by the vehicle and the electric power necessary to supply the first part of the electric consumers. To calculate the electric power available in the vehicle, the unit uses the regulator voltage of the alternator and the current supplied by the alternator, said values of the regulator voltage of the alternator and of the current supplied by the alternator are recorded at each new request for authorization to switch to autonomous urban braking mode. To calculate the electric power available in the vehicle, the box can also use the value of the engine speed in the case where it has a certain stability, for example on an urban axis at constant speed as a peripheral, allowing it to predict the maximum electrical power that can be produced. Otherwise, the box can also use a value of the average engine speed calculated from the previous calculation of the available electric power. To calculate the electric power available in the vehicle, the box can also check the charge level of an auxiliary battery, the auxiliary battery being taken into account in the calculation of said electric power available in the vehicle only beyond d 'a predefined minimum threshold of the charge level of said auxiliary battery.

According to a second characteristic of the invention, to allow passage into said mode, the box also calculates the electric power of a so-called non-priority part of the electrical consumers who are in use, the non-priority part corresponding to consumers in use that can be stopped without impacting the operation of the vehicle in city traffic.

According to a third characteristic of the invention, once the autonomous urban braking mode has been validated, the unit updates the calculation of the electric power available in the vehicle repeatedly according to a given time interval and / or after each autonomous braking in said autonomous urban braking mode. To update the calculation of the electric power available in the vehicle, the box uses average values of the regulating voltage of the alternator U_prod, of the current supplied by the alternator l_prod and of the engine speed calculated since the previous braking in the mode of autonomous urban braking. After each update of the calculation of the available electrical power, the unit gives a new authorization for the autonomous urban braking mode, which may cause the autonomous urban braking mode to stop. In the event of a stop request, an alarm or any other means of alert warns the driver of the imminent exit from autonomous urban driving mode.

The present invention also relates to a vehicle which comprises an electric braking system, an electric power supply network which supplies the electric braking system, a set of electrical consumers of the sensor / actuator type and a control unit adapted to control the electric braking by using at least a first part of the electrical consumers, said vehicle also comprising control means adapted to allow a user of the vehicle to request the control unit to switch to an autonomous urban braking mode, said switch to urban braking being managed by a management process which includes at least one of the preceding characteristics.

The accompanying drawings illustrate the invention:

[Fig.1] represents a flowchart which breaks down the eight main functions of the process for managing the energy authorizations for managing the autonomous electric braking of a vehicle according to the invention.

A vehicle which comprises an electric braking system comprises an electric power supply network to which are coupled at least one set of electrical consumers of the sensor / actuator type and a control unit adapted to control the electric braking system. The vehicle's energy source is supplied by an alternator which allows a battery for the on-board network to be recharged, typically a lead-acid battery and a higher-powered auxiliary battery, using a

higher energy density technology such as a lithium-ion type battery. The vehicle also includes control means adapted to allow a user of the vehicle to request the control unit to switch to an autonomous electric braking mode in urban traffic. According to the invention, the control unit manages the passage of the vehicle in driving mode with autonomous braking in an urban driving mode with what this implies in terms of number of sensors and

actuators to activate due to the large number of traffic parameters to be taken into account. To manage such a passage in autonomous urban braking, the control unit uses a flowchart as shown in FIG. 1, with as inputs:

o an entry request 11 in autonomous urban braking mode;

o a request to exit 12 from the autonomous urban braking mode;

o the activation state of a number n of sensors present in the vehicle and the electrical consumption associated with the activation of each of the n sensors;

o the activation state of a number m of actuators present in the vehicle and the electrical consumption associated with the activation of each of the m actuators;

o a state of charge 41 of the auxiliary power supply;

o the engine speed 61;

o the regulating voltage of the alternator U_prod; and

o the electrical flow of the alternator, i.e. the current supplied by the alternator

Lprod.

At the output, the flowchart allows the control unit to have:

o information for controlling the auxiliary supply recharge 81;

o an authorization for autonomous urban braking 82; and

o a request for load shedding of non-priority electrical consumers 83.

These three output data are in the form of boolean type signals, "1" or "0" or "yes" or "no", allowing the control unit to optimally manage the transition to autonomous urban braking mode, but also to better manage the load of the auxiliary supply 81 and the level of electrical consumption of the entire on-board network so as to avoid consumption peaks while the auxiliary supply 81 is not able to come on help for the lead acid battery and alternator. The organization chart is broken down into eight main functions:

o the first sub-function 1 makes it possible to detect an autonomous urban braking request / output;

o the second sub-function 2 makes it possible to select the sensors and actuators necessary for autonomous urban braking;

o the third sub-function 3 makes it possible to determine the electricity consumption of electric consumers specifically activated for autonomous urban braking; o the fourth sub-function 4 makes it possible to determine the availability of an auxiliary supply;

o the fifth sub-function 5 makes it possible to determine the electrical power specifically necessary for autonomous urban braking;

o the sixth sub-function 6 makes it possible to determine the electric power

specifically available for autonomous urban braking;

o the seventh sub-function 7 makes it possible to determine the capacity to supply electrical power for autonomous urban braking; and

o the eighth sub-function 8 makes it possible to supervise the supply of electrical energy for autonomous urban braking. Each sub-function makes it possible to decompose a complex problem of management of the authorization function of an autonomous urban braking into a series of eight sub-functions which is easier to implement.

Under the first sub-function 1, the conditions for entering and leaving the autonomous urban electric braking mode are gathered. The input requests 11 are generally made by means of the selector actuated by the driver and the output request 12 for autonomous urban braking generally comes from a flow of information whether it is an autonomous urban braking output selector actuated by the driver or a force applied to the brake pedal or to the accelerator pedal in the case where monitoring of the front car is also selected with autonomous urban acceleration activated. But other actions can be taken into account. In response, the sub-function 1 sends information 13 on the state of the autonomous urban braking request, typically of the Boolean type "yes" or "no".

Under the second sub-function 2, all of the sensors and actuators necessary for autonomous urban braking are gathered. This sub-function receives from the first sub-function 1 the status information 13 "yes" of the request for autonomous urban braking. and in response to this information, determines the set of sensors C1 to Cn and actuators A1 to Am, which will be necessary, to manage the autonomous urban braking of the vehicle. Urban traffic characterized by high traffic density areas, requiring greater surveillance of

the environment. Each sensor C1 to Cn and each actuator A1 to Am therefore sending a boolean type signal, "1" or "0" or "yes" or "no", to the third in function 3, in the form of a matrix.

Under the third sub-function 3, the electricity consumption of the actuators and sensors specifically activated in addition for autonomous urban braking is determined. The sensors C1 to Cn and the actuators A1 to Am, which are identified in the second sub-function 2 for carrying out the management of autonomous urban braking, are compared with the actuators and sensors already activated when the request to enter autonomous urban braking mode . Is thus only taken into account in this third sub-function 3, the sensors C1 to Cn and the actuators A1 to Am which were not yet activated before the request for activation of the autonomous urban braking and which will have to be activated. Each sensor C1 to Cn and each actuator A1 to Am is associated with a specific electrical consumption, respectively, EC1 to ECn and EA1 to EAm. At the end of this third under function 3 is therefore returned the sum 35 of the electrical consumptions EC1 to ECn of the sensors C1 to Cn and of the electrical consumptions EA1 to EAm of the actuators A1 to Am specifically activated in addition for autonomous urban braking.

Under the fourth sub-function 4, the energy state of an auxiliary power supply is determined. It may be appropriate to use an auxiliary power source, which can either be added to the conventional power supply of the vehicle, generally formed by an alternator and a 12V battery, or to provide the energy needs independently. linked to the power supply of the vehicle's autonomous urban braking management system. Such an auxiliary power supply can also be used and therefore

sized, to meet other types of energy needs whatsoever

the supply of an electric compressor to increase the power of the engine or an electric catalyst for pollution control issues for example. Typically today, a lithium-ion type battery is preferred for this type of auxiliary power supply, which has a better weight / bulk ratio and stored electrical power than a lead-acid battery. The fourth sub-function 4 determines whether the auxiliary power source has a minimum charge level, enabling it to respond to the energy demands linked to the management of autonomous urban braking in support of the main supply of electrical energy to the vehicle. The fourth sub-function 4 receives at input a state of charge 41 of the auxiliary power supply and returns at output 42 the state of the auxiliary power supply, in the form of a signal of boolean type, "1" or "0" either " Yes or no ".

The fifth sub-function 5 makes it possible to determine the electric power necessary for autonomous urban braking. This sub-function determines the electrical power required, for the management of autonomous urban braking from the current consumed on average during this life phase of the vehicle. The digital value of the sum 35 of the electrical consumption EC1 to ECn of the sensors C1 to Cn and of the electrical consumption EA1 to EAm of the actuators A1 to Am is available as an input.

specifically activated in addition for autonomous urban braking, at the output of the third sub-function 3 and a regulating voltage parameter of the alternator U_prod. The fifth sub-function 5 outputs the electrical power necessary for autonomous urban braking 51, in the form of a power value which is a numerical value. The sixth sub-function 6 makes it possible to determine the electrical power available for autonomous urban braking. The purpose of this sub-function is to determine whether the difference between the electric power consumed by the on-board network of the vehicle and the maximum power that this vehicle can produce, depending on the engine speed at which it operates, is sufficient to meet the additional energy needs. linked to the management of autonomous urban braking. This sub-function therefore predicts the maximum electrical power that the vehicle's electrical energy supply system can provide, depending on the engine speed. This sub-function calculates at all times, the electrical power necessary to supply the various electrical consumers activated on the vehicle, at the time of the calculation. The difference between these two electrical powers gives the reserve of available power which can be allocated to the management of autonomous urban braking. The engine speed 61, the regulating voltage of the alternator U_prod and the electrical flow rate of the alternator, that is to say the current supplied by the alternator l_prod, are used as input. At the output, the sixth sub-function 6 provides the available electrical power 62 which is a numerical value.

The seventh sub-function 7 makes it possible to determine the capacity to supply electrical power for autonomous urban braking. At the input, this seventh sub-function 7 receives the electrical power necessary for autonomous urban braking 51 at the output of the fifth sub-function 5 and the available electrical power 62 at the output of the sixth sub-function 6. By comparison of these two numerical values of power is given, at the output of the seventh under function 7, an autonomous urban electric braking authorization 71 in the form of a signal of boolean type, "1" or "0" or "yes" or

" no ".

The eighth sub-function 8 makes it possible to supervise the supply of electrical energy for autonomous urban braking. This sub-function determines the authorizations for activating the autonomous braking management system in urban traffic, manages the requests for recharging of the auxiliary power supply and also manages the requests for load shedding of so-called non-priority electrical consumers, with respect to management. autonomous urban braking. This eighth sub-function has as input 13 information on the state of the autonomous urban braking request, typically of the boolean type "yes" or "no", the state of the auxiliary power supply 42, in the form of a boolean “Yes” or “no” and the authorization for autonomous urban electric braking 71 in the form of a Boolean type signal, “yes” or “no”. The eighth sub-function 8 provides as output control information for the auxiliary supply recharge 81, an autonomous braking authorization 82 and a load shedding request for non-priority electrical consumers 83, which are in the form of Boolean type signals, "1" or "0" or "yes" or "no".

Claims

1. Activation method for an electric braking system of an autonomous braking mode in city traffic, for a vehicle which comprises an electric power supply network which supplies an electric braking system, a set of electric consumers (C1 to Cn; A1 to Am) of type

sensors / actuators and a control unit adapted to control the electric braking system using at least some of the electrical consumers, said vehicle also comprising control means adapted to allow a user of the vehicle to request the control unit to pass in said autonomous urban braking mode, a first part of the electrical consumers being to be activated specifically for the urban braking mode

autonomous, characterized in that the box, to authorize passage into said autonomous urban braking mode (71), uses an estimate of the electrical consumption (35) of the first part of said electrical consumers to be activated specifically for said braking mode autonomous urban.

2. Method according to claim 1, characterized in that to authorize passage into said mode, the box compares the electric power available in the vehicle with the electric power consumed by the vehicle and the electric power (51) necessary to power the first part of the electrical consumers.

3. Method according to claim 2, characterized in that to calculate the electric power available in the vehicle, the box uses the regulator voltage of the alternator (U_prod) and the current supplied by the alternator (l_prod).

4. Method according to claim 2 or 3, characterized in that to calculate the

electrical power available (62) in the vehicle, the box uses the value of the engine speed (61) allowing said box to predict the maximum electric power that can be produced.

5. Method according to any one of claims 2 to 4, characterized in that to calculate the available electric power (62), the case checks the charge level of an auxiliary battery, the auxiliary battery being taken into account in the calculation of said available electrical power (62) only beyond a predefined minimum threshold of the charge level of said auxiliary battery.

6. Method according to any one of the preceding claims, characterized in that to authorize the passage into said mode, the box also calculates the electric power of a so-called non-priority part of the electric consumers which are in use, the non-priority part corresponding to electrical consumers in use which can be stopped without impacting the

vehicle operation in city traffic.

7. Method according to any one of claims 2 to 6, characterized in that, once the autonomous urban braking mode has been validated, the unit updates the calculation of the available electric power (62) repeatedly according to an interval of given time and / or after each autonomous braking in said urban autonomous braking mode.

8. The method of claim 7 taken in its dependence on

Claims 3 and 4, characterized in that in order to update the calculation of the

available electrical power (62), the box uses average values of the alternator regulation voltage (U_prod), of the current supplied by the alternator

(Lprod) and engine speed (61) calculated from the previous braking in the autonomous urban braking mode.

9. Method according to claims 7 or 8, characterized in that after each

updating of the calculation of the available electrical power (62), the unit gives a new authorization for the autonomous urban braking mode (71), which may cause the said autonomous urban braking mode to stop.

10. Vehicle which comprises an electrical braking system, an electrical supply network which supplies the electrical braking system and a set of electrical consumers (C1 to Cn; A1 to Am) of sensor / actuator type, said vehicle also comprising a control unit adapted to control the electric braking system using at least a first part of the electrical consumers, said vehicle also comprising control means adapted to allow a user of the vehicle to request the control unit to switch to a mode of autonomous urban braking, said transition to urban braking mode being managed by an activation method according to any one of the preceding claims.