FIELD OF THE INVENTION

The present invention relates to a method for determining a maximum speed for vehicle, to a device for determining a maximum speed for vehicle, and to an automated driving system for a vehicle.

BACKGROUND INFORMATION

The braking power of emergency brake assistance systems for vehicles may be reduced for various reasons. For example, the time required to recognize dangerous situations may become longer due to poor weather conditions. In addition, the communication between the components required for emergency braking may become impaired due to a defect, thus increasing the communication time. Finally, deterioration of hydraulic elements of the brake system is also possible, lengthening the brake path.

From DE 10 2013 213 169 A1, it is believed to be understood, after recognizing a defect in components of a vehicle, to put the vehicle into an emergency operating mode and to bring it to a standstill.

SUMMARY OF THE INVENTION

The present invention provides a method for determining a maximum speed for a vehicle having the features described herein, a device for determining a maximum speed for a vehicle having the features described herein, and an automated driving system for a vehicle.

According to a first aspect, the present invention relates to a method for determining a maximum speed for a vehicle. Here, items of state information about a state of at least one vehicle component of the vehicle are received. A maximum speed of the vehicle is determined or calculated, on the basis of the state information, in such a way that a stopping path of the vehicle from a recognition of a dangerous state until the vehicle is at a standstill is less than or equal to a specified value.

According to another aspect, the present invention relates to a device for determining a maximum speed for a vehicle, having an input interface and a determining device. The input interface is configured to receive state information relating to a state of at least one vehicle component of the vehicle. The determining device is configured to determine the maximum speed of the vehicle on the basis of the state information in such a way that a stopping path of the vehicle from a recognition of a dangerous state until the vehicle is at a standstill is less than or equal to a specified value.

According to another aspect, the present invention relates to an automated driving system for a vehicle, having a device for determining a maximum speed for the vehicle and having at least one vehicle component that is coupled to the device and is configured to transmit state information to the device.

Specific embodiments are the subject matter of the respective further descriptions herein.

Vehicle components of the vehicle may be understood as devices of the vehicle that are required for the braking of the vehicle, for example via an automated emergency braking assistant.

The state information concerning the state of the vehicle components may include items of information about a possible impairment of the vehicle components. The state information can also include items of information about a period of time that the corresponding vehicle component requires for its respective contribution to the braking of the vehicle.

If the state of one or more vehicle components is impaired, then in general the stopping path of the vehicle at a specified vehicle speed will become longer. As a result, in specific cases a safe braking of the vehicle may no longer be guaranteed. According to the present invention, therefore, the maximum speed of the vehicle is determined in such a way that the stopping path does not exceed a specified threshold value. In this way, safe braking, and thus prevention of accidents, are possible at all times.

At the same time, the maximum speed may be chosen to be as high as possible, without the stopping path exceeding the specified value. This makes it possible for the driver, or an automatic driving system, to convey the vehicle to a safe parking position or to a repair shop without presenting an obstacle for other traffic participants.

The state information may include information about a state of at least one vehicle sensor of the vehicle, such that on the basis of the information about the state of the at least one vehicle sensor, a recognition time is calculated that is required for recognizing the dangerous state. The maximum speed is determined taking into account the recognition time. The vehicle sensors can for example include radar sensors, infrared sensors, or vehicle cameras that monitor a surrounding environment of the vehicle and are configured to recognize objects in the surrounding environment of the vehicle. The information about the state can include information about a degree of precision of recognition of the at least one vehicle sensor, ascertained for example on the basis of weather conditions around the vehicle.

According to a development, the items of state information include information about a state of a brake system of the vehicle, a braking time from the beginning of the braking process until the vehicle is at a standstill being calculated on the basis of the information about the state of the brake system, and the maximum speed being determined taking into account the braking time.

The calculation of the braking time can include the calculation of a first braking time from a beginning of the braking process until the full braking power has been reached, and the calculation of a second braking time from the reaching of the full braking power until the vehicle is at a standstill. The brake system can for example include an antilocking system. The brake system can also include a hydraulic system. The first braking time corresponds to the time required to build up the brake pressure of the hydraulic system. The delay of the vehicle during the pressure buildup phase is in general not constant, whereas during the second braking time the deceleration is essentially constant.

According to a development of the method, the state information can include information about a state of the communication system between the brake system and the at least one vehicle sensor. On the basis of the information about the state of the communication system, a communication time for the communication between the brake system and the at least one vehicle sensor is calculated, and the maximum speed is determined taking into account the communication time. The method according to the present invention thus takes into account possible time losses due to a suboptimal communication between the components required for the emergency braking.

According to a further development of the device, the state information includes information about the state of at least one vehicle sensor of the vehicle, the determining device being configured to calculate, on the basis of the information about the state of the at least one vehicle sensor, a recognition time required for the recognition of the dangerous state. The determining device is in addition configured to determine the maximum speed taking into account the recognition time.

According to a development of the device, the state information includes information about a state of a brake system of the vehicle, the determining device being configured to calculate, on the basis of the information about the state of the brake system, a braking time from a beginning of the braking process until the vehicle is at a standstill, and to determine the maximum speed taking into account the braking time.

According to a development of the device, in order to calculate the braking time the determining device is configured to calculate a first braking time from a beginning of the braking process until the full braking power is achieved, and a second braking time from the reaching of the full braking power until the vehicle is at a standstill.

According to a development of the device, the items of state information include information about a state of a communication system between the braking system and the at least one vehicle sensor, the determining device being configured to calculate, on the basis of the information about the state of the communication system, a communication time for the communication between the brake system and the at least one vehicle sensor, and to determine the maximum speed taking into account the communication time.

In all the Figures, identical or functionally identical elements and devices have been provided with the same reference characters. Specific embodiments can be combined with one another in any manner deemed appropriate.

