Vehicle safety system and method for generating braking force

Abstract

A vehicle's driver assistance system, wherein the driving safety system (1) comprises a separable clutch (2), a device (3) for actuating the clutch (2) and a device (4) for determining a braking requirement or braking request, characterized by the fact that the vehicle is a vehicle that can be operated at least partially automatically, wherein the device (3) for actuating the clutch (2) and the device (4) for determining a braking requirement or request are connected in such a way that the clutch (2) is closed if the vehicle is operated at least partially automatically, wherein an automation system of the vehicle in at least partially automatic operation takes over lateral and longitudinal control of the vehicle, and a braking requirement or request is detected.

Description

[0001] The invention relates to a vehicle safety system, in particular a partially, highly or fully automatically operated vehicle, and to a method for generating a braking force in such a vehicle.

[0002] WO 2010 / 054 883 A1 discloses a method for braking a motor vehicle comprising a drive motor with a gearbox and a wheel brake system, wherein during a braking operation the gear ratio is automatically changed to increase the drag torque of the drive motor.

[0003] German patent DE 10 2010 041 539 A1 discloses a driver assistance system for supporting the driver in fuel-efficient driving with an electronic control system and feedback functions. This predictive assistant consists of a control system and a display as a visual feedback function. The control system, based on route data combined with current vehicle data, evaluates speeds and distances along a predetermined route in such a way that the time or point along the route can be determined from which a predetermined speed can be reached over a specific distance during coasting and / or sailing. Upon reaching this time or point, the control system issues at least a driving recommendation to release the accelerator pedal via the display.

[0004] German patent DE 101 44 797 A1 discloses a method for adjusting automatic driving functions in a vehicle, in which at least one vehicle component is automatically influenced depending on measurement signals from a measuring device that maps the dynamic behavior of the vehicle and / or environmental conditions. During the transition from automatic to manual driving, a current value characterizing the relevant vehicle component is first determined and compared with a manual driver input relating to that component. If the driver input is lower than the current value, the state prevailing in the vehicle component is maintained, or the process running in the driver component continues, until the driver input reaches or exceeds a reference value.

[0005] DE 10 2009 046 340 A1 discloses a method for controlling a rolling or sailing function of a vehicle.

[0006] DE 102 21 701 A1 discloses a control method for motor vehicles with an automated clutch device, with a controllable engine with an engine control device, preferably a controllable automated transmission and at least one electronic control unit for controlling the transmission and the clutch device, in which a speed of the motor vehicle (at least representing a quantity), an actuation of a brake and / or an energy or fuel supply metering element and a state of the engine are detected and, in the event that neither the brake pedal nor the fuel supply metering element is recognized as actuated when the engine is running and the vehicle speed is greater than a limit value, the clutch is opened.

[0007] DE 195 32 946 A1 discloses a control arrangement for controlling the engine braking operation of a motor vehicle.

[0008] DE 199 20 065 A1 discloses a method for carrying out automated clutch actuation.

[0009] DE 35 90 104 T5 discloses an automatic transmission which automatically shifts and controls the gear position of a transmission depending on the speed of a vehicle, as well as the control of the engagement and disengagement of the clutch.

[0010] In the design of known braking systems, such as the previously described prior art braking systems, it is assumed that a driver can take over control of the vehicle with little or no delay in the event of a simple fault in the braking system. In the event of a fault, the driver can generate braking force, for example, by pressing a brake pedal. Therefore, the auxiliary braking effect that the braking system must provide in the event of a fault can be less than the service braking effect that can be provided when the braking system is functioning correctly. Auxiliary braking, in this context, refers to braking in which the energy required to generate the braking force is derived from the physical force of the driver and one or more energy supply devices.In contrast, external braking refers to braking of the vehicle during which braking force or pressure is generated exclusively by an actuator, such as a pump or an electric motor. In this case, the energy required to generate the braking force is supplied by one or more energy supply devices, excluding the physical force of the driver.

[0011] The area of ​​partially, highly, or fully automated driving is increasingly becoming a focus of automotive development. While the driver is physically present in automated driving, they can be distracted. In automated operation, the driver can be so distracted that they can only regain control of the vehicle, particularly braking, with an undesirable delay.

[0012] The technical problem therefore arises of creating a vehicle safety system, in particular a partially, highly or fully automated vehicle, and a method for generating a braking force in such a vehicle, which also enables safe operation of the vehicle in the event of a simple fault in the braking system, especially if a driver only takes over driving the vehicle with a delay.

[0013] The solution to the technical problem is achieved by the objects having the features of claims 1 and 6. Further advantageous embodiments of the invention are set forth in the dependent claims.

[0014] A vehicle safety system is proposed, in particular a partially, highly or fully automated motor vehicle.

[0015] The terms "highly automatic" and "fully automatic" describe different levels of vehicle automation. In addition to these levels, further levels of automation, such as "driver only" and "assisted," may exist. In a highly automated vehicle, for example, lateral and longitudinal control can be performed by the vehicle's automation system, without the need for the driver to continuously monitor the automation system or the vehicle's operation. In a fully automated vehicle, the automation system completely takes over lateral and longitudinal control in a defined application. Here, the driver no longer needs to monitor the automation system or the vehicle's operation. In a "driver only" vehicle, the driver continuously performs longitudinal and lateral control.In an assisted-driven vehicle, the driver continuously performs either lateral or longitudinal control. The other driving task is performed within certain limits by the automation system, whereby the driver must continuously monitor the automation system and the vehicle control. In a partially automated-driven vehicle, according to the invention, the automation system takes over lateral and longitudinal control, whereby the driver must continuously monitor the automation system and the vehicle control.

[0016] A basic idea of ​​the invention is that a separable clutch of the vehicle is closed if the vehicle is at least partially operated automatically and a braking requirement or request is detected.

[0017] The driving safety system, and therefore the vehicle itself, includes a separable clutch and a device for actuating, i.e., opening and closing, the clutch. The driving safety system can also be referred to as the vehicle's clutch and brake system. It may, for example, comprise the vehicle's clutch and brake systems, or at least parts thereof.

[0018] The clutch can, for example, be part of the vehicle's clutch system, with the vehicle safety system encompassing the clutch system or parts thereof. For instance, the clutch can be part of the vehicle's transmission. For example, the clutch can connect or disconnect an output shaft of an engine, particularly an internal combustion engine or an electric motor, to an input shaft of the transmission. The clutch can be engaged or disengaged by means of the clutch actuation device. This actuation device can be operated manually by a driver or automatically, for example, by control commands or signals from an automation system. The actuation device can be part of the clutch system.

[0019] Furthermore, the driving safety system includes at least one device for determining a braking requirement or a braking request. This determination device can, for example, be part of the vehicle's braking system, with the driving safety system encompassing the braking system.

[0020] A braking request can be detected, for example, when the driver presses the vehicle's brake pedal. For this purpose, the braking system can, for instance, use a force sensor to detect the brake pedal press. A braking requirement can be determined, for example, when the vehicle is approaching a vehicle in front too closely. The braking system can include distance sensors that detect the distance to a vehicle ahead or to other traffic objects, and the vehicle's braking requirement can be determined based on the distance detected by these sensors. Thus, a braking requirement or a braking request can be determined based on driver input or on output signals from driver assistance systems.

[0021] According to the invention, the vehicle is at least partially automatically operable. For example, the vehicle can be semi-, highly, or fully automatically operable. The device for actuating the clutch and the device for detecting a braking requirement or request are connected in such a way that the clutch is engaged if the vehicle is operating at least partially automatically, for example, semi-, highly, or fully automatically, and a braking requirement or request is detected. For example, the clutch can be engaged if semi-, highly, or fully automatic operation of the vehicle is activated or is already activated and a braking requirement or request is detected.

[0022] For example, the device for actuating the clutch and the device for determining a braking requirement or request can be connected via signal technology, for example by a data bus system, in such a way that the device for determining a braking requirement or request can generate and transmit a control signal for the device for actuating the clutch, whereby the device for actuating the clutch closes the clutch if the vehicle is at least partially operated automatically and a braking requirement or request is detected.

[0023] The braking system, or a part thereof, can thus be used to control the clutch actuation device. The braking system can influence the clutch actuation device in such a way as to prevent the clutch from disengaging and / or a related gear shift. Typically, the corresponding control signals are transmitted via a data bus system, such as a CAN bus or a FlexRay bus.

[0024] When the clutch is engaged, an additional braking torque can be generated, namely the braking torque of the drive unit, e.g., the internal combustion engine. This is also known as drag torque. This advantageously means that, when braking is required or desired in at least partially automatic operation, the braking force still required by auxiliary braking, external braking, or manual braking can be lower than when the clutch is disengaged.

[0025] In a further embodiment, the braking system, and thus also the driving safety system, includes a device for detecting a simple fault in the braking system. The device for actuating the clutch and the device for detecting a simple fault are connected in such a way that the clutch is engaged if a simple fault is detected in the braking system.

[0026] For example, the device for actuating the clutch and the device for detecting a single fault can be connected via signal technology, for example by a data bus system, in such a way that the detection device can generate a control signal for actuating the clutch and transmit it to the device for actuating the clutch, whereby the device for actuating the clutch closes the clutch.

[0027] The clutch may engage if a simple fault is detected in the braking system, either in partially automatic mode or in manual mode ("driver only"). Furthermore, the clutch may engage only if a braking request or requirement is detected, or if no such request or requirement is detected.

[0028] This advantageously results in the fact that, in the event of a single fault, the previously described braking torque (drag torque) of the drive unit is already provided, meaning that the braking effect to be generated by the faulty braking system must be lower than in the disengaged state. For example, it may be necessary for the braking system, in a fault-free state, to achieve a predetermined braking deceleration, for example, at least 6.43 m / s² according to regulation ECE-R13H. 2 The system must generate a predetermined braking force applied by the driver to the brake pedal, whereby the threshold duration must not exceed a predetermined threshold value, for example, 600 ms. A threshold duration, in this context, refers to the time from the start of brake pedal actuation until the previously described braking acceleration is reached.

[0029] Since, in at least partially automated operation, the driver may be so distracted that, upon the occurrence of a simple fault, they can only resume control of the vehicle with a delay, for example, after a predetermined period, it is desirable that the previously described service braking effect—that is, the braking acceleration that the braking system can generate in its fault-free state—can be achieved even when a simple fault is present. By engaging the clutch, i.e., closing the clutch when a simple fault occurs, the braking acceleration to be generated in the event of a fault is advantageously reduced by the proportion of the braking force generated by the drive unit, so that the previously described service braking effect can be achieved more easily even in the case of a simple fault.

[0030] In another embodiment, the vehicle's idle control can be deactivated if the vehicle is at least partially operated automatically and a braking requirement or request and / or a simple fault is detected.

[0031] Idle speed control refers to the regulation of the engine's rotational speed to a predetermined idle speed of the output shaft, for example, an idle speed between 700 rpm and 900 rpm for an internal combustion engine. When deactivated, fuel is withheld to prevent the engine from maintaining this predetermined idle speed. The engine speed can then drop below this predetermined idle speed, causing the engine to stop or shut off, similar to a start-stop system. Idle speed control can also be deactivated if the vehicle's speed falls below a predetermined speed, such as a predetermined minimum speed. This ensures that the engine continues to operate even below this minimum speed.When the vehicle is stationary or about to come to a standstill, it remains active and generates sufficient electrical energy for electrical consumers as a generator.

[0032] This ensures a continuous power supply to vehicle-mounted consumers and actuators, such as a power steering pump or a vacuum pump for the braking system, provided by the engine, for as long as possible during braking. Thus, the power supply to the steering and braking systems, for example, can be maintained even if the engine speed drops below a predetermined idle speed during braking.

[0033] In another embodiment, the idle speed control can be reactivated when a predetermined speed is reached that is less than the predetermined idle speed in normal operation, or when a speed is reached that is less than the predetermined minimum driving speed.

[0034] The predetermined rotational speed or velocity can be selected in such a way as to minimize the probability of stalling due to a drop in the rotational speed of the drive unit. This advantageously prevents the drive unit from coming to a complete stop or standstill, even if the idle speed control is deactivated down to the predetermined rotational speed.

[0035] The predetermined minimum driving speed can be greater than, for example, 1 km / h, 2 km / h, 3 km / h, 4 km / h or 5 km / h.

[0036] In another embodiment, the braking system is designed such that the clutch can be disengaged for the duration of a shifting process if the vehicle is at least partially operated automatically and a braking requirement or request and / or a simple fault is detected.

[0037] This advantageously eliminates, at least for the duration of the shifting process, the requirement that the clutch must always be engaged when the vehicle is operating at least partially automatically and a braking requirement or request and / or a simple fault is detected. This advantageously enables controlled downshifting.

[0038] A further proposed method for generating braking force in a vehicle is described, wherein the vehicle is operated at least partially automatically, for example, semi-, highly, or fully automatically. In this method, a braking requirement or request is detected, and in at least partially automatic operation, a clutch of the vehicle is engaged if a braking requirement or request is detected. This advantageously results in a method for generating braking force that reduces the braking force that would otherwise be required, for example, in the context of power-assisted braking, auxiliary braking, or manual braking, since the engagement of the clutch already generates a braking torque through a drive unit of the vehicle, such as an internal combustion engine.

[0039] In a further embodiment, a braking system is monitored for a single fault, and in at least partially automatic operation, the clutch is engaged if a single fault is detected. This advantageously reduces the braking force that would otherwise have to be generated by the braking system in the event of a single fault, e.g., a braking force generated by external power braking, auxiliary power braking, or manual braking.

[0040] In a further embodiment, the vehicle's idle speed control is deactivated when the vehicle is operating at least partially automatically and a braking requirement or request and / or a simple fault is detected. For example, a predetermined idle speed can be set during non-automatic operation. This control can be deactivated if the vehicle is operating at least partially automatically and a braking requirement or request is detected. This advantageously ensures a power supply to other vehicle components via the drive unit, which operates as a generator, even if the vehicle decelerates to a speed below the predetermined idle speed. The vehicle's idle speed control can also be deactivated if the vehicle's speed falls below a predetermined speed, such as a predetermined minimum driving speed.This ensures that the drive unit remains active below speed, e.g. when the vehicle is stationary, and generates sufficient electrical energy for the electrical consumers as a generator.

[0041] In another embodiment, the idle speed control is reactivated when a predetermined speed is reached that is lower than the idle speed during normal operation. Alternatively, the idle speed control can be reactivated when a predetermined speed is reached that is lower than a predetermined minimum vehicle speed. This advantageously prevents the drive unit from stopping or at least reduces the likelihood of it stopping.

[0042] In a further embodiment, the clutch is disengaged for the duration of a shifting operation if the vehicle is operating at least partially automatically and a braking requirement or request and / or a simple fault is detected. This advantageously allows, for example, controlled downshifting even if the vehicle is operating at least partially automatically and a braking requirement or request is detected, since for the duration of the shifting operation the condition that the clutch is always engaged if the vehicle is operating at least partially automatically and a braking requirement or request and / or a simple fault exists is suspended.

[0043] The invention is explained in more detail using an exemplary embodiment. The single figure shows a schematic block diagram of a vehicle's braking system.

[0044] In Fig.Figure 1 is a schematic block diagram of a vehicle safety system 1 of a vehicle not shown, which can be operated semi-, highly, or fully automatically. The vehicle safety system 1 comprises a clutch system 11 and a brake system 12. The clutch system 11 comprises a separable clutch 2 and a device 3 for actuating the clutch. The brake system 12 comprises a device 4 for determining a braking requirement or request, a brake pedal 5, and a device 10 for detecting a simple fault in the brake system 12. A braking request can be determined, for example, if a driver (not shown) depresses the brake pedal 5. A braking requirement can be determined if a driver assistance system 6 for distance control of the vehicle determines that braking is necessary.Furthermore, the vehicle or the driving safety system 1 includes a device 7 for controlling semi-automatic, highly automatic, or fully automatic operation of the vehicle. The device 3 for actuating the clutch engages the clutch 2 if the vehicle is operating in semi-automatic, highly automatic, or fully automatic mode and a braking requirement or request is detected by the device 4. The clutch 2 is mechanically arranged between a drive unit 8 and a transmission 9 of the vehicle. The drive unit 8 can be, for example, an internal combustion engine or an electric motor. The clutch system 11, the brake system 12, the transmission 9, and the drive unit 8 are interconnected by a data bus system 13. Via this data bus system 13, the device 4 can prevent the clutch 2 from being opened by the device 3 for actuating the clutch 2 when it detects a braking requirement or request.

[0045] Furthermore, the brake system 12 includes the device 10 for detecting a single fault in the brake system 1. The device 3 for actuating the clutch closes the clutch 2 when a single fault is detected by the device 10 in the brake system 1. Reference symbol list 1 Driving safety system 2 clutch 3. Clutch actuation device 4 Device for determining a braking requirement or request 5 Brake pedal 6 Driver assistance systems 7 Device for detecting automatic operation 8 Drive unit 9 gearboxes 10. Device for detecting a single fault 11 Coupling system 12. Braking system 13 Data bus

Claims

[1] Vehicle safety system, wherein the driving safety system (1) comprises a separable clutch (2), a device (3) for actuating the clutch (2) and a device (4) for determining a braking requirement or braking request, characterized by , that the vehicle is a vehicle that can be operated at least partially automatically, wherein the device (3) for actuating the clutch (2) and the device (4) for determining a braking requirement or request are connected in such a way that the clutch (2) is closed if the vehicle is operated at least partially automatically, wherein an automation system of the vehicle in at least partially automatic operation takes over lateral and longitudinal control of the vehicle, and a braking requirement or request is detected. [2] Driving safety system according to claim 1, characterized by, that the driving safety system (1) comprises a device (10) for detecting a single fault in a braking system (12), wherein the device (3) for actuating the clutch (2) and the device (10) for detecting a single fault are connected such that the clutch (2) is closed if a single fault is detected in the braking system (1). [3] Driving safety system according to one of the preceding claims, characterized by , that the vehicle's idle control can be deactivated if the vehicle is at least partially operated automatically and a braking requirement or request and / or a simple fault is detected. [4] Driving safety system according to claim 3, characterized by , that the idle speed control can be reactivated when a predetermined speed is reached that is less than a predetermined idle speed, or when a speed is reached that is less than a predetermined minimum driving speed. [5] Driving safety system according to any of the preceding claims, characterized by , that the braking system is designed such that the clutch (2) can be disengaged for the duration of a shifting operation when the vehicle is at least partially operated automatically and a braking requirement or request and / or a simple fault is detected. [6] Method for generating a braking force in a vehicle, wherein the vehicle is operated at least partially automatically, wherein a braking requirement or a braking request is determined, wherein in the at least partially automatic operation a clutch (2) is closed if a braking requirement or request is detected, wherein an automation system of the vehicle in the at least partially automatic operation takes over lateral and longitudinal control of the vehicle. [7] Method according to claim 6, characterized by, that a brake system (12) is monitored for a simple fault, whereby in at least partially automatic operation the clutch (2) is closed if a simple fault is detected. [8] Method according to any one of claims 6 to 7, characterized by , that the vehicle's idle control is deactivated if the vehicle is at least partially operated automatically and a braking requirement or request and / or a simple fault is detected. [9] Method according to claim 8, characterized by , that the idle speed control is reactivated when a predetermined speed is reached that is less than a predetermined idle speed, or when a speed is reached that is less than a predetermined minimum driving speed. [10] Method according to any one of claims 6 to 9, characterized by, that the clutch (2) is disengaged for the duration of a shifting operation when the vehicle is at least partially operated automatically and a braking requirement or request and / or a simple fault is detected.

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