This invention relates to a safety device for a motor vehicle with
at least one sensor unit for detecting the environmental conditions and for the output of environmental data, an evaluation unit for merging the environmental data and an evaluation unit for detecting free spaces and objects, and the position and movement thereof, and with
at least one sensor unit for detecting the state of the environment and for the output of environmental status data and an evaluation unit for merging the environmental data with the environmental status data to determine a proposed coefficient of friction, and with
at least one sensor unit for detecting the vehicle state and for the output of vehicle status data and an evaluation unit for merging the vehicle status data with driver input data to determine the driving state, and with
at least one sensor unit for detecting the driver inputs and for the output of driver input data and an evaluation unit for merging the driver input data with the vehicle status data to determine the driver's setpoint course. The invention further relates to a method for operating a motor vehicle.
Such a safety device and method for increasing safety in road traffic is known from EP 1 735 187 A1. In the known system, a supporting driving maneuver is determined during or after a steering action as part of an avoidance maneuver initiated by the driver, wherein the driver input can be overridden at any time. This known method determines based on environmental signals if a critical situation with respect to driving dynamics exists or if a collision is imminent. The method is preferably used for avoidance maneuvers in emergency situations.
It is the object of the present invention to introduce a method which, taking into account the driving situation, proactively ensures maximum driving safety that supports the driver in his or her driving job as best as possible.
This object is achieved by a method and device having the features of the independent claims. A system and a method are proposed for situation and collision phase optimized brake force control and chassis adjustment for combined braking/avoidance maneuvers for motor vehicles. A driving safety coordinator is provided that calculates the collision risk based on a risk assessment. In addition, the driving safety coordinator determines multiple precollision phases of the vehicle with respect to the object. In this process, the driving safety coordinator determines the last point to brake for stopping before reaching the object, a last point to steer of the unbraked vehicle for evading and a last point to steer of the braked vehicle for avoiding the object. The precollision phases are designed such that they start or end at these points. One rationale of the invention is that the driving safety coordinator extends the precollision phases situatively by a driver-independent braking intervention.
The decisive inventive idea is that the driving safety coordinator predictively and situatively performs a combined braking/avoiding maneuver within the precollision phases of the motor vehicle to ensure operational safety. In this way, the driving safety coordinator makes the precollision phases controllable for the driver, either situatively or based on driver input, in accordance with the collision risk, the vehicle state and the proposed coefficient of friction, taking into account an avoidance option, a combined braking/avoiding maneuver or a braking maneuver.
In a further development of the subject matter of the invention, the driving safety coordinator receives information regarding the coefficient of friction between the tire and the road based on an estimate, wherein the proposed coefficient of friction is determined from a driver-independent or driver-initiated braking intervention.
In a particularly advantageous development, the driving safety coordinator predictively and situatively determines at least one permissible driving corridor and/or an optimal movement trajectory in order to ensure operational safety and restricts the driver input to the driving corridor using actively addressable components and keeps the motor vehicle in the driving corridor or on the movement trajectory using the actively addressable components. The driving safety coordinator is configured to give the driver a haptic, acoustic and/or optical warning and/or steering recommendation.
The problem underlying this invention is also solved by a device having the features of claim 9. A safety coordinator calculates the collision risk and determines precollision phases of the motor vehicle with respect to the object. In this process, the last point to brake for stopping before reaching the object, a last point to steer of the unbraked vehicle for evading, and a last point to steer of the braked vehicle for avoiding the object are determined. The precollision phases start or end at these points. The precollision phases are also extended by means of a driver-independent braking intervention.
The decisive inventive idea is that a combined braking/avoiding maneuver is performed predictively and situatively within the precollision phases of the motor vehicle to ensure operational safety. In this way, the precollision phases are optimized and made controllable for the driver, either situatively or based on driver input, in accordance with the collision risk, the vehicle state and the proposed coefficient of friction, taking into account an avoidance option, a combined braking/avoiding maneuver or a braking maneuver.
Another decisive idea is that the precollision phases are redetermined if another object is detected in the direction of movement of the vehicle. In a subsequent scenario, the precollision phases are repeated if another obstacle occurs after or during a change into another lane. The respective phases of the method will then be repeated.
The invention will be explained in more detail below, with reference to an embodiment and the enclosed figure. Wherein:
a,b shows the longitudinal and transverse forces of a vehicle tire, also known as Kamm's circle.
The term “steering wheel” in the meaning of this invention represents all conceivable man-machine interfaces that a driver can operate for steering and driving the motor vehicle, such as switch inputs, a joystick or a touch pad, as well as remotely transmitted actuator commands.
A safety device for motor vehicles in general will be explained with reference to
Furthermore, the information about the environment can be detected using so-called car-to-x communication. This means transmission of environmental information from other vehicles or detection points to the vehicle 1. The environment sensors 2 measure the distances d to the detected points of an object and the angles φ between the connecting lines to these points and the central longitudinal axis of the vehicle, as shown by way of example in
At least one sensor unit 2 is used to detect the environmental conditions. As stated above, this system of environment sensors 2 is comprised of a radar, lidar, or video camera system or a combination thereof. The information obtained using at least one of these sensor units 2 is pooled with map information, GPS data and information received using car-to-x communication to obtain an environmental information pool in an evaluation unit 4. After the merger of the data, the improved environmental data is evaluated with the purpose of detecting objects O. The position and movement information of an object O is sent to a driving safety coordinator 6. This driving safety coordinator 6 determined precollision phases P1, P2, P3, P4a, P4b based on limits of driving physics and taking into account the environment data, and thus predictively and situatively ensures the operational safety of the vehicle 1 in that the precollision phases P1, P2, P3, P4a, P4b are designed such that a combined braking/avoiding maneuver or a braking maneuver is performed. The precollision phases P1, P2, P3, P4a, P4b are explained in more detail with reference to
As can further be derived from
Another at least one sensor unit 30 is used to detect the vehicle state. The at least one sensor unit 30 for detecting the vehicle state consists of a wheel speed sensor, a lateral acceleration sensor, a longitudinal acceleration sensor, and/or a yaw rate sensor. A combination of the sensors mentioned is also conceivable. The sensor unit 30 for detecting the vehicle state is also called vehicle status monitor. An evaluation unit 34 associated with the vehicle status monitor combines the vehicle status data with the determined coefficient of friction proposal in the form of a data merger. The vehicle status is calculated in this way in step 35 and output to the driving safety coordinator 6.
As
Thus the position and movement of the object O and the determined coefficient of friction proposal are transmitted to the driving safety coordinator 6. The driving safety coordinator 6 also receives information about the vehicle state and the driver's setpoint course. These data are used to determine a permissible driving corridor or an optimum movement trajectory. The driving corridor or movement trajectory is determined situatively and predictively. The driving corridor or movement trajectory bypass the object O on its left and right within the predicted avoidance space. To keep the vehicle 1 in the permissible corridor or optimum movement trajectory, active components 9 are actuated such that the driver input is restricted to the available corridor or optimum movement trajectory. These actively addressable components 9 are located in the chassis or in a man-machine interface such as brake pedal, driving engine, steering system, transmission, shock absorber, stabilizer, or direction indicator. The driving safety coordinator 6 actuates the actively addressable components 9 such that a counterforce is generated in the accelerator pedal, an intervention in the driving engine, an intervention in the power train, or a braking interventions is performed to keep the vehicle in the driving corridor or movement trajectory. Alternatively, or in addition, the actively addressable components 9 are actuated such that an additional steering torque and/or additional steering angle or a braking intervention aimed at individual wheels is generated to generate a yaw moment. This actuation is also suited to keep the vehicle in the driving corridor or movement trajectory. In a special embodiment, the driver can override each action of the system, so that the driver keeps control over his or her vehicle 1.
It will now be explained with reference to
In the precollision phase 1, the driving safety coordinator 6 calculates a last point to brake (PTB). In addition, a last point to steer PTS-u of the unbraked vehicle 1 and a last point to steer PTS-b of the braked vehicle 1 are determined. The abbreviations PTS-u and PTS-b were derived from the English terms “last point to steer—unbraked” and “last point to steer—braked lane change”. The lane can be changed to the left or to the right and several subsequent times, as shown. A multi-object and multi-collision situation is assumed for multiple avoidance maneuvers.
As can also be derived from
If at the start of precollision phase P3 the brake pressure of a driver-independent braking intervention in the wheel brakes is reduced or lowered down to zero, the wheels will be easier to steer because more steering force can be transferred to the road, as has been explained as well. If the brake pressure is reduced or lowered to zero at the start of precollision phase 3, the last point to steer moves towards the obstacle or object O. This last point to steer is then the PTS-u of the unbraked vehicle 1, since the brake pressure was reduced to zero. This means that the position and length of the precollision phase P3 is changed by the distribution of the brake force. The method described here utilizes this knowledge in that the driving safety coordinator 6 situatively influences the position and length of the precollision phase P3 between the last point to steer PTS-u of the unbraked vehicle 1 for evasion and the last point to steer PTS-b of the braked vehicle 1 for avoiding the object O by means of a driver-independent braking intervention to optimize an emergency brake operation in the precollision phase P4a or an avoidance maneuver in the precollision phase 4b. The brake force of the driver-independent braking intervention may either be distributed evenly or unevenly over the right and left wheels of the vehicle 1, so that the avoidance maneuver is supported if the brake force is distributed unevenly.
If there is no avoidance space available, the brake power is optimized at an early point in time well before the PTS-u so that as much speed as possible is lost. The driver is warned respectively earlier. This means that the driving safety coordinator initiates an emergency brake operation in the precollision phase P4a if there is no avoidance option available. In this case, the brake power is optimized in the precollision phase 4a. A collision of the vehicle 1 with the object O can just be avoided by this measure, or the consequences of the collision are reduced as much as the space available as brake path allows.
The driving safety coordinator 6 predictively and situatively determines at least one permissible driving corridor and/or an optimum movement trajectory in order to ensure operational safety. As explained with reference to
If an avoidance option is detected, a combined braking/avoiding maneuver is performed in precollision phase P3. In the subsequent phase 4b, the driver-independent braking intervention is released again so that the rapid passage by the obstacle is not is not hindered. If the lane is blocked by another obstacle O, the precollision phases P1′, P2′, P3′, P4a′, and P4b′ are determined anew. Another combined braking/avoiding maneuver is performed in accordance with the new precollision phases P1′, P2′, P3′, P4a′, P4b′.
The evaluation units 4, 5, 24, 25, 34, 35, 44, 45 may also be designed as software components or process steps of a method within a common evaluation unit.
In the present invention, a driving safety coordinator, taking into account the environment, environmental conditions, the vehicle state and the driver input, divides a critical driving situation into the precollision phases P1, P2, P3, P4a, P4b and influences the position and length of phase P3 by means of driver-independent braking interventions such that an emergency brake operation P4a, an emergency avoidance maneuver P4b, or a combined emergency braking/avoiding maneuver is optimized. It is also configured that the precollision phases P1′, P2′, P3′, P4a′, P4b′ are determined anew when another object O is detected in the direction of movement of the vehicle 1.
Number | Date | Country | Kind |
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10 2011 005 262.3 | Mar 2011 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP12/53994 | 3/8/2012 | WO | 00 | 8/29/2013 |