WO2016139048A1

WO2016139048A1 - Method and device for ascertaining the presence of a fault state in a motor vehicle

Info

Publication number: WO2016139048A1
Application number: PCT/EP2016/053014
Authority: WO
Inventors: Bernd Mueller; Carsten Gebauer; Simon Hufnagel; Thomas Hartgen; Isidro Corral Patino; Markus Reichert; Thomas Mauer; Andreas Grimm; Evgeniya Ballmann
Original assignee: Robert Bosch Gmbh
Priority date: 2015-03-03
Filing date: 2016-02-12
Publication date: 2016-09-09
Also published as: KR20170126990A; CN107278190A; CN107278190B; KR102496881B1; DE102015203782A1

Abstract

The invention relates to a method for reliably operating a motor vehicle (1) by means of a motor vehicle control system, comprising a propulsion regulation unit (98) driving first components (31, 32, 33, 34, 40, 100). The propulsion regulation unit (98), upon receipt of a warning in a yaw rate warning signal, drives the first components (100, 40) such that a sum yaw rate produced by all of the first components (100, 40) does not exceed a sum yaw rate threshold value.

Description

Description title

Method and device for determining whether a fault condition exists in a motor vehicle or not

State of the art

The invention relates to a method for determining whether or not there is a fault condition in a motor vehicle. The invention further relates to a device, in particular a control device, which is set up to carry out this method.

From DE 44 38 714 AI a method for driving the drive power of a vehicle is known, wherein a microcomputer is provided for performing control functions and monitoring functions. Microcomputers are defined at least two independent levels, wherein a first level performs the control function and a second level, the monitoring function.

Disclosure of the invention

Due to the presence of new actuators for propulsion, as can be realized, for example, in electric vehicles or hybrid vehicles, it is possible that faults lead to a faulty yaw moment being generated. For example, this can be done by a faulty asymmetric acceleration (or deceleration, so negative acceleration) of different wheels.

In a first aspect, therefore, a method for safe operation of a motor vehicle is provided, wherein the motor vehicle is a motor vehicle control includes. The motor vehicle control system optionally includes a braking-activating vehicle dynamics control unit with which, for example, wheels of the motor vehicle can be braked individually and independently of one another (for example an ESP system), and a propulsion control unit for activating first components, which are also referred to below as propulsion components, because they include, inter alia can be used to create propulsion. The brakes used here are, for example friction brakes. The propulsion control unit may be, for example, a motor controller. The propulsion components comprise a motor, in particular an internal combustion engine, and optionally a generator-operable electric machine, in particular a generator or starter-generator. For example, if the propulsion control unit receives a warning from the vehicle dynamics control unit in a yaw rate warning signal (the yaw rate warning signal may be a binary signal, for example, where a "1" indicates that there is a warning and a "0" indicates that there is no alert) Propulsion control unit, the propulsion components such that a total of the propulsion components impressed sum yaw moment is not greater than a sum yaw moment limit (if here and below is spoken by yawing moments, this may in particular relate to an absolute value of the yaw moment).

This has the advantage that a safety concept for the propulsion control unit can also be represented for those errors in the propulsion control unit which generate a faulty yaw moment, so that these errors can be adequately reflected. When the propulsion control unit receives the warning in the yaw rate warning signal, it is thus ensured that the propulsion control unit controls the components which it can control in such a way that, overall, they generate a sufficiently small yaw moment. The vehicle dynamics control unit can continue to generate another yaw moment by appropriate control of the brakes. Safety mechanisms in the vehicle dynamics control unit can ensure that this further yaw moment can not cause dangerous conditions. The described measures of the propulsion control unit can ensure that it does not reduce the effectiveness of safety mechanisms of the vehicle dynamics control unit. Compared to a compensation of a yaw movement caused by the erroneous yaw moment, the method is particularly efficient if the erroneous yaw moment is caused by an error in the drive control.

The driving dynamics control unit can be used here to recognize and detect this (erroneous) yawing movement, ie an actual yaw rate, as implausible. In parallel, it can be provided that the vehicle dynamics control unit controls the yawing movement by means of appropriate control interventions, e.g. on the brakes trying to compensate.

That the yaw rate warning signal received by the propulsion control includes a signal indicating whether the actual yaw rate of the motor vehicle is taking an erroneous value.

Alternatively or additionally, it may be provided that the yaw rate warning signal comprises a signal which indicates whether the vehicle dynamics control unit controls components that can be controlled by it in such a way that they generate a yawing moment. That the yaw rate warning signal may include a signal indicating whether there is a control intervention by the vehicle dynamics control unit.

By limiting the sum yaw moment, the vehicle dynamics control unit may be allowed to complete this control intervention without interference by the propulsion control unit. As a result, the action of the propulsion control unit can be adjusted to the action of the vehicle dynamics control unit in such a way that the vehicle control system is brought into a safe state. In particular, the sum yaw moment limit may be zero. This ensures that the propulsion control unit can not actively impose a yaw moment on the motor vehicle, i. a yaw-moment-neutral fallback level is created in the event that an implausible yaw rate is determined.

The limitation of the summation yaw moment impressed by the propulsion components can be effected by the fact that, when the warning is received, the propulsion control unit controls an electric machine such that a maximum recuperation power of the electric machine is not greater as a recuperation limit. This is based on the knowledge that the recuperation of kinetic energy during deceleration processes produces a braking torque which, especially when acting asymmetrically, can lead to a yawing moment. A blockage of a rear axle of the motor vehicle during decelerations can also lead to a yaw moment. Such a blockage can be prevented by limiting the maximum recuperation power. At the same time, the energy disadvantage of this measure is minimal, since such interventions are extremely rare.

The recuperation limit value can be chosen to be so large that a sum torque applied by the propulsion components to a rear axle of the motor vehicle is positive. As a result, blocking of the rear axle can be prevented particularly efficiently, since it is ensured that no active delay is set via the rear axle. This allows recuperation, as long as it is ensured that the engine imposes a larger driving torque on the rear axle than the decelerating torque that imposes the recuperation.

In a further aspect, it is possible that when the warning is present, a Rekuperationsmodus a controllable by the propulsion control unit electric machine is deactivated. This means that the recuperation mode is prohibited and possibly left. As a result, the generation of a yawing moment by the engine control is suppressed particularly efficiently.

In particular, with the so-called torque-vectoring functionality, it is possible that the wheels individually impressed different driving torques. These can be used to generate a desired yaw moment. It is also possible that wheel-individually mounted generators impose individually different braking torques on the wheels.

In a further aspect it can therefore be provided that, when the warning is received, all the wheels of the motor vehicle which can be controlled by the propulsion control unit are impressed by the propulsion components with the same sum torque. This can be done for example by switching off the said torque vectoring functionality. In particular, be ensured that no erroneous yawing moments are impressed by wheel individually different impressed torques.

In another aspect, it may be provided that when the alert is received, a left-hand summed torque propulsion component imprinted on the left-hand wheels of the motor vehicle is the same size as a right-hand squib torque of the propulsion components impressed on the right wheels of the motor vehicle. This can be ensured in particular that no faulty yawing moments are imprinted by an asymmetry between the right and left side of the motor vehicle.

In a further aspect it can be provided that when the warning is received, no switching operations of a transmission take place. This is particularly useful in automatic transmissions, as transmission interventions also transmit torques to the wheels of the motor vehicle, which can generate a yaw moment.

In a further aspect, it can be provided that the driving of the propulsion components takes place in such a way that, without taking into account the yaw rate warning signal, that is to say independently of the yaw rate warning signal, a nominal control of the propulsion components is determined. When the propulsion control unit receives the warning, an expected summation yaw moment corresponding to the target propulsion is determined. This is yawing moment, which would result if the propulsion components were actually controlled with the desired control. If the expected sum yaw moment is greater than the sum yaw moment limit value, a modified setpoint drive is determined so that the sum yaw moment (ie the yaw moment that will result when the drive components coincide with the set point) is determined Control) is not greater than the sum yaw moment limit. The modified setpoint control replaces the setpoint control. This makes it particularly easy to establish a monitoring entity that monitors that no inadmissible yawing moments are generated by the propulsion components. In a further aspect, a method for checking the correctness of the

Reaction of the propulsion control unit may be provided in this method. It is provided here that the yaw rate warning signal comprises a test signal, wherein the test signal indicates whether a test mode is active or not. If the warning is received and if the test signal indicates that the test mode is active, it is provided that the propulsion control specifies a nominal control whose corresponding expected sum yaw moment is greater than the sum yaw moment limit value. Depending on the target drive and the modified target drive, it may be decided whether or not there is an error in the reaction of the propulsion control unit. This makes it particularly easy to increase the safety of the vehicle control system, since now also errors in the error reaction of the propulsion reaction can be detected and effectively treated.

In a refinement, in particular if the yaw rate warning signal indicating the warning is transmitted by the vehicle dynamics control unit, it may be provided that the propulsion control unit transmits a signal for activating the test mode to the vehicle dynamics control unit and subsequently receives the warning with the test signal from the vehicle dynamics control unit in response thereto. As a result, a check of the correctness of the reaction of the propulsion control unit can be provided in a particularly simple manner.

Through the measures presented here, a fallback level is created in the event of a faulty yaw rate, which does not represent a limp home mode. Rather, it is easily possible to switch from this fallback level back to normal operation. It is therefore not necessary, for example, to set a warning lamp in such an intervention.

In other aspects, the invention relates to a computer program configured to perform all the steps of one of the methods according to one of the aforementioned aspects, to an electronic storage medium on which the computer program is stored, and to a controller configured to perform all the steps of one of the methods to perform according to one of the aforementioned aspects.

The figures show examples of particularly advantageous embodiments of the invention. Show it: 1 shows a drive train of a motor vehicle;

Figure 2 is a structural diagram of signal flows in the monitoring;

FIG. 3 is a flowchart of the possible procedure of the method for determining that an error exists;

FIG. 4 shows a flowchart for the possible sequence of the method for responding to the detected error;

Figure 5 is a flow chart for possibly checking the correct operation of the yaw moment limiting method.

Description of the embodiments

1 shows an example of a drive train of a motor vehicle 1. The motor vehicle 1 has four wheels 11, 12, 13, 14. The wheels are each assigned a wheel brake 21, 22, 23, 24 and optionally in each case an electric hub motor 31, 31, 33, 34. Further provided is a generator 40 which can impose a decelerating torque on a crankshaft 101 (not shown). The generator 40 may also be designed as a starter generator. When the generator imposes a decelerating torque, it generates energy that can be stored in energy storage (not shown). This process is called recuperation.

An internal combustion engine 100 generates a driving torque that is transmitted via the crankshaft 101 and an advantageously automated transmission 110 to a drive shaft 102 and further to a rear axle drive shaft 103.

An ESP controller 50 is provided to drive the brakes 21, 22, 23, 24. For example, the ESP controller 50 receives from a yaw rate sensor 60 a signal representing a current actual yaw rate of the motor vehicle 1. If the actual yaw rate assumes an implausible, erroneous value, the ESP control unit 50 can be set up to apply the brakes 21, 22, 23, 24 in this way. control that a yaw moment is generated to translate the implausible actual yaw rate into a non-critical range. This is called ESP control intervention.

Via a communication relationship 51, the ESP control unit 50 can communicate with an engine control unit 98. This communication relationship 51 can be constructed, for example, via a suitable bus system such as CAN or FlexRay. Through the communication relation 51, the engine controller 98 receives a yaw rate warning signal in which it is coded whether an ESP control intervention is present and / or whether the determined yaw rate is implausible or erroneous.

Of course, this information can be provided in various forms, e.g. as a special bit combination in a message or via the sending of actual and target yaw rates or similar. Preferably, communication over the communication link 51 is timed, e.g. periodically. A period may e.g. 10 ms or 20 ms. Further, it is advantageous if the information is suitably hedged. In addition to the CAN or FlexRay-specific safeguards that are already given by the communication protocol, use of Andungs CRC and / or message counters and / or other known end-to-end hedges is advantageous.

The engine control unit 98 receives from sensors, for example, a temperature sensor 71 and an air mass meter 72, signals about the actual operating state of the internal combustion engine 100, the motor vehicle 1 and the environment. These signals are received by an input interface 96. There, the engine controller 98 may also receive the yaw rate warning signal. In an electronic storage medium 99, for example, a computer program is stored that executes the inventive method when it expires. In the execution of the method, control variables such as, for example, a target ignition angle ZW and / or a desired opening degree alpha of a throttle valve (not shown) are communicated to the internal combustion engine 100. This transmission takes place via an output interface 95. The generator 40, for example, receives a torque M to be recuperated, a transmission control device 120 controlling the transmission 110, for example, information about the necessity of a gear change. FIG. 2 shows information flows within the engine control unit 98. Via the input interface 96, the engine control unit 98 receives input quantities xi. The input interface 96 transmits the input quantities xi to a function block 1000, eg, determined in a conventional manner as a function of the input variables xi output variables. These output variables are usually values of a setpoint control xs, with which the internal combustion engine 100, the starter-generator 40 and the motors 31, 32, 33, 34 are controlled. The input variables xi and the desired control xs are thus to be understood as tuples of a multiplicity of values.

The input interface 96 transmits the received yaw rate warning signal 96 to a check block 1010. The check block 1010 is advantageously shielded from errors in the function block 1000 by freedom-from-interference measures, for example, by executing the functions performed by it on another processor core of the controller 98 It may also be provided that the check block 1010 and the function block 1000 use a double file for the data you have read and / or written when accessing the electronic storage medium. Furthermore, it can be provided that the monitoring block 1010 and / or the function block 1000 are protected by control flow-checking mechanisms.

The check block 1010 is configured to check whether or not there is a warning in the yaw rate warning signal gws. Advantageously, the yaw rate warning signal comprises two bits: a first bit indicating whether the actual yaw rate detected by the yaw rate sensor 60 assumes an erroneous value, and a second bit indicating whether a control intervention of the ESP controller 50 exists. For example, instead of the first bit, it is also possible for the yaw rate warning signal gws to transmit the actual yaw rate. If the check block has decided that the warning is present, a warning message wm is sent to a response block 1020. Further, a control block 1030 is provided. The control block 1030 and / or the response block 1020, like the verification block 1010, may be shielded and secured against faults in the functional block 1000. The function block 1000 does not necessarily place the desired control xs on the reaction block 1020. Function block 1000 and / or check block 1010 and / or reaction block 1020 and / or control block 1030 are placed on separate controllers.

When the reaction block 1020 receives the warning message wm, the function block 1000 determines a modified output variable xsm, that is to say a modified setpoint control xsm with which the internal combustion engine 100, the starter generator 40 and the motors 31, 32, 33, 34 are actuated. The modified setpoint control xsm is advantageously determined as a function of the setpoint control xs and modifies this setpoint control xs in such a way that the components controlled by the setpoint control xs do not generate a yaw moment that is greater than the summation yaw momentum limit value. The determination of the modified setpoint control xsm can possibly take place with recourse to the function block 1000. If the reaction block 1020 does not receive a warning message wm, the setpoint control xs is not modified, ie the modified setpoint control xsm is equal to the setpoint control. The modified nominal control xsm is then transmitted to the output interface 95. The modified setpoint control xsm, like the setpoint control xs, is to be understood as a tuple.

It is also possible that the yaw rate warning signal gws does not send the corresponding message only when the actual yaw rate is detected as defective, but rather that a plurality of warning thresholds are provided, whereby the yaw rate warning signal gws transmits which of these thresholds exceeds the actual yaw rate. The transmission of the warning message wm and the determination of the setpoint control xsm are then advantageously also stepped, so that a smooth transition of the motor vehicle 1 from a mode without modification of the setpoint control xs takes place in a mode with modification of the setpoint control xsm.

The control block 1030 is provided, which receives the yaw rate warning signal from the input interface 96, and from the function block 1000, the target drive xs and from the reaction block 1020 the modified target drive 1030. The control block 1030 checks the operation of the verification block 1010 and the reaction block 1020. For this purpose, it transmits the function block 1000 an intervention signal ns. If the control block 1030 determines that there is an error, it may provide the function block 1000 with a suitable ns input signal, whereupon the function block 1000 may take appropriate action to activate, for example, a limp home mode.

FIG. 3 shows a method of determining whether the warning is present or not. The method advantageously proceeds in the verification block 1010. In a first step 3000, the yaw rate warning signal gws is received. In a following step 3010 it is checked whether the yaw rate warning signal gws indicates that there is an ESP control intervention. If so, step 3020 follows, otherwise step 3030 follows. In step 3030, a check is made to see if the yaw rate warning signal gws indicates that the actual yaw rate of the motor vehicle 1 is taking an erroneous value. If so, step 3020 follows, otherwise step 3040 follows.

In step 3020, it is decided that there is a warning. Following is step 3050, in which reaction block 1020 receives the warning message wm. At step 3040, the process ends.

FIG. 4 shows a flowchart for a method for carrying out a response to the warning message wm. This process advantageously proceeds in reaction block 1020. In a first step 4000, the signal containing the information whether or not the warning message wm is received is received. In the following step 4010, it is checked whether the warning message wm is present. If this is the case, step 4020 follows, in which the modified setpoint control xsm is determined. Otherwise, step 4030 follows, ending the procedure.

In step 4020, one or more of the following measures may be used in determining the modified target drive xsm. The modified setpoint control xsm can be determined such that a nominal recuperation power transmitted by the output interface 95 of the electric machine (40) can be limited such that it does not exceed ßer is, as the recuperation limit, which is stored for example in the electronic storage medium 99.

Alternatively or additionally, the modified setpoint control xsm can be determined such that the driving (positive) torque impressed on the rear axle of the motor vehicle 1 by the electric motors 32, 34 and of the internal combustion engine 100 is determined. The recuperation threshold may then be selected so that the braking (negative) torque applied by the starter generator 40 to the rear axle is not greater than the driving torque, so that the sum torque is positive as the sum of driving and braking torque.

Alternatively, the modified setpoint control xsm can be selected so that the recuperation mode of the starter-generator 40 is electrically deactivated.

Alternatively or additionally, the modified desired control xsm can be selected such that the same applies to all wheels 11, 12, 13, 14 of the electric motors 31, 32, 33, 34, the internal combustion engine 100 and the starter-generator 40 (sums -) torque is impressed.

Alternatively or additionally, the modified desired control xsm can be selected such that a left-hand sum torque of the electric motors 33, 34 of the starter-generator 40 and of the internal combustion engine 100 imprinted on the left wheels 13, 14 of the motor vehicle 1 is the same a right-hand sum torque impressed on the right wheels 11, 12 of the motor vehicle 1, electric motors 31, 32, the starter-generator 40 and the internal combustion engine 100th

Alternatively or additionally, the modified setpoint control xsm can be selected such that a command is transmitted to the transmission control unit 120 for not performing a gear change in the transmission 110.

The selection of the measures mentioned can take place with a stepped warning signal ws depending on the level of the warning. FIG. 5 shows a flow chart for a method for checking whether the limitation of yaw moment imposed by the propulsion components 31, 32, 33, 34, 40, 100 is functioning properly. This method advantageously proceeds in control block 1030.

Step 5000 marks the start of the procedure. In the following optional step 5010, the engine control unit 98 transmits to the ESP controller 50 a request to perform a yaw torque limit function test and to transmit an ESP control action.

In the following step 5020, the engine controller 98 receives the yaw rate warning signal gws from the ESP controller 50 (eg, in response to the request sent in step 5010). The yaw rate warning signal gws also includes a test signal indicating whether a test mode is actually present or not. This test signal is not evaluated by the control block 1010.

In the following step 5030, it is checked whether the test signal contains the information that the test mode is actually present and whether the yaw rate warning signal contains the information that there is an ESP control intervention. If so, it follows

Step 5040, otherwise step 5080, at which the method ends.

In step 5040, the control block 1030 transmits the request to the function block 1000 to predefine the desired control xs in such a way that a yawing moment would be generated when this setpoint control xs is implemented.

In the following step 5050, it is checked whether the target drive xs actually assumes values that would generate a yaw moment and whether the modified setpoint drive xsm is different from the setpoint drive. If so, step 5060 follows, otherwise step 5070.

In step 5060, it is assumed that the monitoring block 1010 and the reaction block 1020 are functioning properly, and the method ends. In step 5070, an error response is initiated, for example, by communicating to function block 1000 the command to initiate a limp home mode. Optionally, it can be provided that an error counter is incremented and this error reaction is only initiated when the error counter exceeds a predefinable error limit.

Claims

claims

A method for safely operating a motor vehicle (1) having a motor vehicle control system comprising a propulsion control unit (98) which activates first components (31, 32, 33, 34, 40, 100), wherein the propulsion control unit (98), when in a yaw rate warning signal (ges) receives a warning, the first components (100, 40) so controls that a total of the first components (100, 40) generated sum yaw moment is not greater than a sum yaw moment limit.

2. The method of claim 1, wherein the yaw rate warning signal (gws) comprises a signal indicating whether an actual yaw rate of the motor vehicle (1) assumes an erroneous value.

3. The method of claim 1 or 2, wherein the yaw rate warning signal (gws) comprises a signal indicating whether a brake (21, 22, 23, 24) driving the vehicle dynamics control unit (50) from its controllable components (21, 22, 23, 24) so that they generate a yawing moment.

4. The method according to any one of the preceding claims, wherein when the warning is received, the propulsion control unit (98) an electric machine (40) controls such that a maximum recuperation of the electric machine (40) is not greater than a Rekuperations- limit.

5. The method of claim 4, wherein the Rekuperations limit value is chosen so large that one of the first components (32, 34, 40, 100) on a rear axle (12, 14, 103) of the motor vehicle (1) imprinted summation Torque is positive.

6. The method according to any one of claims 1 to 5, wherein in which, when the warning is present, a Rekuperationsmodus one of the propulsion control unit (98) controllable electric machine (40) is deactivated.

7. The method according to claim 1, wherein when the warning is received, all the wheels (11, 12, 13, 14) of the motor vehicle (1) that can be controlled by the propulsion control unit (98) are moved by the first components (31, 31 , 33, 34, 40, 100) the same sum torque is impressed.

A method according to any one of claims 1 to 7, wherein, when the warning is received, a left-side cumulative torque of the first components (33, 34, 40, 100) impressed on the left wheels (13, 14) of the motor vehicle (1) is equal to a right wheels (11, 12) of the motor vehicle (1) imprinted right-hand sums torque of the first components (31, 32, 40, 100).

9. The method according to any one of claims 1 to 8, wherein when the warning is received, no switching operations of a transmission (110) take place.

10. Method according to one of the preceding claims, wherein the control of the first components (31, 32, 33, 34, 40, 100) takes place in such a way that initially, without taking into account the yaw rate warning signal (gws), a desired drive (xs) of the first components (xs) 31, 32, 33, 34, 40, 100), it is determined that when the propulsion control unit (98) receives the warning, an expected sum yaw moment corresponding to the target propulsion (xs) is detected, and wherein the expected sum yaw moment is greater than the sum yaw moment limit value, a modified setpoint drive (xsm) is determined so that the sum yaw moment to be expected is not greater than the sum yaw moment limit value.

11. The method of claim 9, wherein the yaw rate warning signal (gws) comprises a test signal, wherein the test signal indicates whether a test mode is active or not, and wherein if the warning is received and if the test signal indicates that the test mode is active, the propulsion control (98) specifies a desired control (xs), the corresponding expected of the sum yaw moment is greater than the sum yaw moment limit value, and depending on the target drive (xs) and the modified target drive (xsm), whether or not there is an error in the reaction of the propulsion control unit is decided ,

12. The method of claim 10, wherein the propulsion control unit (98) transmits to the vehicle dynamics control unit (50) a signal for activating the test mode and subsequently one of the vehicle dynamics control unit (50) issues the warning with the test signal indicating that the test mode is active , receives.

A computer program adapted to perform all the steps of one of the methods of any one of claims 1 to 12.

14. An electronic storage medium (99) on which the computer program according to claim 13 is stored.

A controller (98) adapted to perform all the steps of one of the methods of any one of claims 1 to 12.