Speed ​​assistant for a motor vehicle

Abstract

Procedure (200) for steering a motor vehicle (105), comprising the following steps: - Controlling (205) a longitudinal speed of the motor vehicle (105) to a predetermined value; - Scanning (210) an upcoming driving route (140) by means of a sensor (120) on board the motor vehicle (105); characterized by - Determining (225) an end of a section (305) of the route (140) visible by means of the sensor (120); - Assuming (235) an obstacle (320) on the route (140) beyond the visible section (305); - Determine (245) that a delay required to maintain a predetermined minimum distance to the assumed obstacle (320) exceeds a predetermined threshold, and - Issuing (255) a signal to a driver of the motor vehicle (105).

Description

[0001] The invention relates to a speed assistant for a motor vehicle. In particular, the invention relates to a transfer of control from the speed assistant to a driver. State of the art

[0002] The patent application DE 10 2011 106 808 A1 discloses a method for avoiding a collision for a vehicle.

[0003] The patent application DE 101 49 768 A1 discloses a method for determining the visibility range of a detection device attached to a vehicle.

[0004] A speed assistant is designed to maintain a vehicle's speed at a predetermined value. This relieves the driver of the task of controlling the vehicle's longitudinal position. In one variant, the system also determines the distance to a vehicle ahead and controls the vehicle's speed to maintain a predetermined minimum distance. This may involve reducing the vehicle's speed below the predetermined limit. The distance to the vehicle ahead is determined, for example, using a radar or video sensor.

[0005] In certain situations, it is necessary to return control of the vehicle's longitudinal speed to the driver. For example, if the vehicle is following another vehicle and a third vehicle cuts in between them, the minimum required distance to the vehicle in front may suddenly be breached. In this case, the vehicle may need to decelerate beyond a predetermined threshold, beyond which braking would not be perceived as comfortable. In this situation, the driver may be prompted to take over speed control.

[0006] DE 10 2004 005 229 A1 shows a distance control system for motor vehicles.

[0007] A corresponding warning or prompt may come as a surprise to the driver, potentially overwhelming them in their ability to react appropriately to the prevailing traffic situation. The invention therefore aims to provide a technique for improved communication of a motor vehicle's speed control to the driver. The invention achieves this objective through the subject matter of the independent claims. Dependent claims describe preferred embodiments. Disclosure of the invention

[0008] An inventive method for controlling a motor vehicle comprises the steps of controlling the longitudinal speed of the motor vehicle to a predetermined value and scanning an upcoming route using a sensor on board the motor vehicle. In this process, an end of a section of the route visible to the sensor is determined, an obstacle on the route beyond the visible section is assumed, it is determined that a deceleration required to maintain a predetermined minimum distance to the assumed obstacle exceeds a predetermined threshold, and a signal is issued to a driver of the motor vehicle.

[0009] This way, the driver can be alerted early on that the adaptive cruise control may soon be deactivated. The signal can also be interpreted as a general warning of a situation in which the vehicle will decelerate.

[0010] In one variant, the obstacle is assumed to be a vehicle that moves ahead along the route at a predetermined speed.

[0011] This assumption can be accurate in many cases, and a typical minimum vehicle speed can be assumed. By assuming an obstacle is moving away from the vehicle, only a lesser or later deceleration is required to maintain the predetermined minimum distance. This allows for greater flexibility in deceleration. As a result, the automatic maintenance of the minimum distance can be interrupted or deactivated less frequently.

[0012] In another variant, it is assumed that the obstacle on the road is stationary. This pessimistic assumption allows for a better assurance that the vehicle can be brought to a stop in time before reaching the obstacle. The vehicle's longitudinal steering can therefore be designed more defensively.

[0013] In one embodiment, it can be determined that an object lies within the sensor's scanning area, shading a section of the driving path within the scanning area, and that the end of the visible section corresponds to the beginning of the shaded section. This allows for the particular consideration of frequently encountered, possibly temporary, reductions in the visible section.

[0014] The route can, for example, describe a bend, with the object located on the inside of the bend next to the route. This allows for better consideration of vegetation or buildings alongside the route that temporarily shorten the visible portion.

[0015] Longitudinal speed control can be terminated if the distance to the assumed obstacle falls below a predetermined threshold. This embodiment is particularly useful for situations where the visible area is significantly reduced, for example, to the length of one or more vehicles. Such a situation might occur when turning into a street or a driveway. Even if the vehicle's speed in this case is lower than when driving on a highway, the system can proactively increase the driver's attention to the significantly reduced visibility by taking this into account in a timely manner.

[0016] Ideally, the signal is issued before an actual obstacle is detected on the road. Instead, the driver can be alerted to an approaching situation where automatic speed control or distance maintenance reaches its limits. This can lead to an overall increase in vehicle safety.

[0017] In one variant, longitudinal speed control is suspended as long as the deceleration required to maintain the minimum distance to the obstacle assumed to be beyond the visible section exceeds the predetermined threshold. In other words, longitudinal speed control can be automatically resumed as soon as the vehicle can be safely and comfortably delineated based on the available scan results, if necessary.

[0018] In a further embodiment, if the required field of vision is obstructed, the vehicle's speed is adjusted to a value that would allow for a predetermined maximum deceleration and thus a comfortable adjustment of the longitudinal guidance, should an obstacle be detected in the relevant driving area. In other words, the longitudinal speed of the vehicle can be reduced until the deceleration required to maintain a predetermined minimum distance to the assumed obstacle meets the predetermined threshold.

[0019] By adjusting the longitudinal speed, subsequent braking to avoid a collision with the assumed obstacle can still be considered comfortable. Braking is only initiated if the obstacle actually exists or is actually detected. In this way, longitudinal speed can be automatically and cautiously controlled. Collision avoidance with an obstacle can thus be achieved in two stages.

[0020] In one embodiment, several alternative routes are determined, and the signal determination is performed for all routes. Such a speculative review of various available routes allows for dynamic adjustments to the driver's behavior.

[0021] A computer program product according to the invention comprises program code means for carrying out the described method when the computer program product runs on a processing device or is stored on a computer-readable data carrier.

[0022] A device according to the invention for controlling a motor vehicle comprises a speed control for maintaining the longitudinal speed of the motor vehicle at a predetermined value, a sensor on board the motor vehicle for scanning an upcoming route, and a signaling device for outputting a signal to a driver. Furthermore, a processing unit is provided which is configured to determine the end of a section of the route visible by means of the sensor, to determine that a deceleration required to maintain a minimum distance to an obstacle assumed to be located beyond the visible section of the route exceeds a predetermined threshold, and to output this information to the driver of the motor vehicle by means of the signaling device.

[0023] The device allows a known motor vehicle with longitudinal speed control to be improved in such a way as to result in safer driving behavior. Brief description of the characters

[0024] The invention will now be described in more detail with reference to the attached figures, in which: Fig. 1 a device for controlling a motor vehicle; Fig. 2. A flowchart of a procedure for controlling the motor vehicle of Fig. 1, and Fig. 3 and Fig. 4 situations of the motor vehicle of Fig. 1 during the tax process according to the procedure of Fig. 2 is represented. Detailed description of exemplary implementations

[0025] Fig. Figure 1 shows a device 100 on board a motor vehicle 105. The motor vehicle 105 comprises a drive motor 110 and a braking device 115. The device 100 comprises a sensor 120, a signaling device 125, and a processing device 130. The sensor 120 can, for example, be a video or radar sensor. The signaling device 125 is configured to provide a signal to a driver of the motor vehicle 105 and can signal acoustically, visually, or haptically. Furthermore, a speed control 135 is provided, which in the illustrated embodiment is included by the processing device 130. In another embodiment, however, the speed control 135 can also be implemented independently of the processing device 130.

[0026] The speed control 135 acts on the drive motor 110 and, optionally, on the braking device 115 to implement longitudinal control of the motor vehicle 105. The speed of the motor vehicle 105 is preferably controlled to a predetermined value. If the motor vehicle 105 threatens to collide with a vehicle ahead, which can be determined, for example, by means of the sensor 120, the speed control can be deactivated in favor of distance control. A predetermined distance is then preferably maintained between the motor vehicle 105 and the vehicle ahead.

[0027] The processing unit 130 is configured to return longitudinal control of the motor vehicle 105 from the speed control 135 to a driver when it is determined that strong deceleration is required to maintain a distance between the motor vehicle 105 and an object located on the road 140. For this purpose, a signal is issued to the driver by means of the signaling device 125 and / or the speed control 135 is deactivated. The deceleration can be considered strong, in particular, if it exceeds a predetermined deceleration value.

[0028] The processing unit 130 determines in advance whether a situation arises in which safe longitudinal guidance of the motor vehicle 105 cannot be guaranteed under all circumstances.

[0029] Fig. Figure 2 shows a flowchart of a procedure 200 for controlling the motor vehicle 100. Fig. 1. The method 200 is specifically designed to run on the processing unit 130. For this purpose, the processing unit 130 may preferably comprise a programmable microcomputer.

[0030] In a first step 205, the motor vehicle 105 is controlled to a predetermined speed by means of the speed control 135. Simultaneously, the area around the motor vehicle 105 is scanned by means of the sensor 120. In a step 215, one or more alternative upcoming routes 140 are determined. The following steps can be carried out separately for multiple routes 140. The upcoming routes 140 can be derived from the signals of the sensor 120 or, for example, be determined based on a planned route from a navigation system.

[0031] In step 220, it is determined that a section of the route 140 is shaded for sensor 120. In step 225, a distance to the shading point is determined. In step 230, it is checked whether the distance is less than a predetermined threshold. This threshold can, for example, be speed-dependent, so that it is higher when the vehicle 105 is traveling fast and lower when the vehicle 105 is traveling slowly. If the distance is not less than the threshold, then in step 235 an obstacle is assumed to be present in the shaded section, as explained in more detail below. Fig. 3 is explained. A distance to the obstacle is determined in step 240. Based on this, in step 245 it is determined how much deceleration would be necessary to maintain a predetermined minimum distance between the motor vehicle 105 and the obstacle.

[0032] In step 250, it is checked whether the specified deceleration exceeds a predetermined maximum deceleration. If this is not the case, the procedure 200 can branch back to the beginning and be repeated. Otherwise, in an optional step 255, which may also be included in the following step 260, a signal can be issued to the driver of the motor vehicle 105 to take over longitudinal control by means of the signaling device 125. This step can also be executed if it was determined in step 230 that the distance of the motor vehicle 105 to the shadowing point falls below the predetermined threshold.

[0033] Subsequently, the cruise control 135 can be deactivated in a subsequent step 260. The procedure 200 can be designed such that the cruise control 135 is automatically reactivated when the criteria required for deactivation are no longer present, or it can require a specific action by the driver to reactivate the cruise control 135 within the framework of the procedure 200. This action could, for example, involve operating an input device.

[0034] Fig. Figure 3 shows a first situation of the motor vehicle 105 from Fig. 1 during the tax process of procedure 200.

[0035] The road 140, on which the vehicle 105 is located, is two lanes in the illustrated example and describes a curve in the area of ​​the vehicle 105. A visible section 305 of the sensor 120 has a substantially triangular shape in the illustration. An oncoming vehicle 310 is located in section 305 and can be detected. Preferably, it is also detected that the vehicle 310 is not in the same lane as the vehicle 105 and is therefore not relevant for longitudinal control of the vehicle 105.

[0036] On the inside of the bend in the roadway 140, there are one or more objects 315 that shading part of the roadway 140 and reducing the visible section 305. An obstacle 320 located behind the objects 315, as seen from the vehicle 105, could be relevant for the longitudinal control of the vehicle 105.

[0037] Based on signals from sensor 120, a shadowed section 318 located behind object 315 is determined. Using method 200, the obstacle 320 in the shadowed section 318 is then determined, assuming a predetermined speed for the obstacle 320. If the distance 140 between the assumed obstacle 320 and the vehicle 105 is still long enough to allow the vehicle 105 to decelerate sufficiently slowly, if necessary, without violating a minimum distance to the obstacle 320, the speed control 135 can remain activated. Otherwise, the driver of the vehicle 105 is signaled that a situation may be imminent in which the automatic longitudinal control of the vehicle 105 can no longer be safely carried out.

[0038] Fig. Figure 4 shows another situation of motor vehicle 105. Fig. 1 during the tax process using procedure 200 of Fig. 2. In the example shown, different routes 140 can be selected by the driver of the motor vehicle 105. The procedure 200 of Fig. 2 must therefore be carried out for each of the possible routes 140, if necessary. If a reason arises to deactivate the speed control 135 on one of the routes 140, a corresponding signal can be issued to the driver of the motor vehicle 105 even if the other routes 140 are clearly visible.

[0039] It is assumed that the motor vehicle 105 is depicted as follows: Fig.When vehicle 105 turns right at the intersection, a section of the roadway 140 behind object 315, extending to just before the actual turn, is not visible. If a stationary obstacle 320, such as another vehicle, is located in the section 318 obscured by object 315, this may be noticed too late to allow vehicle 105 to brake safely. Using method 200, the obstacle 320 can be assumed to be stationary in the obscured section 318, and the speed control 135 can be maintained as long as a safe stop before the assumed obstacle 320 is possible based on the speed and distance of vehicle 105 to the obstacle 320.

Claims

[1] Procedure (200) for steering a motor vehicle (105), comprising the following steps: - Controlling (205) a longitudinal speed of the motor vehicle (105) to a predetermined value; - Scanning (210) an upcoming driving route (140) using a sensor (120) on board the motor vehicle (105); characterized by - Determining (225) an end of a section (305) of the route (140) visible by means of the sensor (120); - Assuming (235) an obstacle (320) on the route (140) beyond the visible section (305); - Determine (245) that a delay required to maintain a predetermined minimum distance to the assumed obstacle (320) exceeds a predetermined threshold, and - Issuing (255) a signal to a driver of the motor vehicle (105). [2] Method (200) according to claim 1, wherein the obstacle (320) is assumed to be a vehicle moving ahead at a predetermined speed on the driving track (140). [3] Method (200) according to claim 1, wherein it is assumed that the obstacle (320) on the travel path (140) is stationary. [4] Method (200) according to one of the preceding claims, wherein it is determined that in the scanning area of ​​the sensor (120) there is an object (315) which shades a section of the driving path (140) in the scanning area and the end of the visible section (305) corresponds to the beginning of the shaded section (318). [5] Method (200) according to claim 4, wherein the travel path (140) includes a bend and the object (315) is located on the inside of the bend next to the travel path (140). [6] Method (200) according to one of the preceding claims, wherein the control of the longitudinal speed is terminated (260) if the distance to the assumed obstacle (320) falls below a predetermined distance (230). [7] Method (200) according to one of the preceding claims, wherein the signal (255) is issued before an actual obstacle (320) is detected on the track (140). [8] Method (200) according to any of the preceding claims, wherein the control of the longitudinal speed is suspended (260) for as long as the deceleration required to maintain the minimum distance to the obstacle assumed to be beyond the visible section (305) exceeds the predetermined threshold (250). [9] Method (200) according to any of the preceding claims, wherein the longitudinal speed of the motor vehicle (105) is reduced until the deceleration required to maintain a predetermined minimum distance to the assumed obstacle (320) complies with the predetermined threshold. [10] Method (200) according to one of the preceding claims, wherein several alternative upcoming routes (140) are determined (215) and the determination of the signal for all routes (140) is carried out. [11] Computer program product with program code means for carrying out the method (200) according to one of the preceding claims, if the computer program product runs on a processing device (130) or is stored on a computer-readable data carrier. [12] Device (100) for controlling a motor vehicle (105), comprising: - a speed control (110) for controlling the longitudinal speed of the motor vehicle (105) to a predetermined value; - a sensor (120) on board the motor vehicle (105) for scanning an upcoming driving route (140), and - a signaling device (125) for issuing a signal to a driver, characterized by a processing facility (130) which is equipped to - to determine the end of a section (305) of the driving route (140) that can be seen by means of the sensor (120); - to determine that a delay required to maintain a minimum distance to an obstacle (320) assumed to be beyond the visible section (305) on the route (140) exceeds a predetermined threshold, and - to issue a signal to the driver of the motor vehicle (105) by means of the signaling device (125).

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