Method for determining maximum limit speed

Abstract

The present invention is a method for determining the maximum speed limit (v max The present invention relates to a method for determining a vehicle speed (v) based on a current vehicle speed (v), a speed limit value of an upcoming speed limit zone (v G ), and the distance to the beginning of the speed limit area (d z In a next step (B), the previously determined values ​​(v, v G , d z ) the time (t) to the speed limit area is estimated. In the next step (C), the speed increase (Δv) for the current vehicle speed (v) depending on the time (t) to the speed limit area is determined. Then, the current vehicle speed (v), the speed increase (Δv), and the distance (d z ) at the start of the speed limit area, G ) to decelerate (a v ) is estimated (D) and the estimated deceleration (a v ) is the deceleration limit value (a G ), decrease the determined velocity increase (Δv) (E).

Description

[Technical Field]

[0001] The present invention relates to a method for determining a maximum limit speed of a motor vehicle before the start of a speed-restricted area, and further to a control unit for carrying out the method. [Background technology]

[0002] In order to relieve the driver, modern vehicles are increasingly being provided with automated driving functions, such as highway driving assistance or parking assistance, or in the future also steering functions, whereby such functions can also control driving regulation, i.e., the acceleration or deceleration of the vehicle.

[0003] German Patent Application Publication No. 102009058393 discloses a method for automatically changing a cruise control speed from a current speed zone to a next speed zone. A point in front of a moving vehicle where the maximum permitted speed for the zone changes from the current maximum permitted speed to the next maximum permitted speed is determined. A speed profile is then determined for changing the vehicle speed from the current maximum permitted speed to the next maximum permitted speed. The speed profile includes a nonlinear change in vehicle speed between the current speed zone and the next speed zone to eliminate abrupt changes in vehicle speed.

[0004] The problem here is if the traffic sign appears at a slightly greater distance and the vehicle is not traveling at the maximum permitted speed, for example, how strongly and for how long the vehicle must accelerate in order to avoid unnecessarily braking again at the traffic sign, but also to avoid driving at a low speed for too long. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] German Patent Application Publication No. 102009058393 Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the problem underlying the present invention is to provide a method for calculating an ideal target speed so as not to accelerate unnecessarily before a region having a speed limit value or to drive at an unnecessarily low speed.

Means for Solving the Problems

[0007] To solve this problem, a method for determining the maximum speed limit of a motor vehicle before the start point of a speed limit region, having the features of claim 1, is proposed. Further, a control unit for a driving assistance system including an arithmetic unit for executing this method, having the features of claim 11, is presented. Preferred embodiments can be seen from the dependent claims.

[0008] The present invention presents a method for determining the maximum speed limit of a motor vehicle before the start point of a speed limit region. Here, the speed limit region is a region where driving should be at a speed lower than the maximum speed limit. Here, this lower speed (hereinafter referred to as the speed limit value) may result from safety considerations or legal regulations. Here, the maximum speed limit is the speed at which the motor vehicle can be accelerated maximally before the speed limit region.

[0009] To determine this maximum speed, first, the current vehicle speed, the speed limit value of the speed limit region approaching ahead, and the distance to the start point of the speed limit region are determined. Based on these values, the time until the speed limit region is estimated. Therefore, the approximate time it takes for the motor vehicle to reach the start point of the speed limit area is estimated. Next, a speed increase with respect to the current vehicle speed, which depends on the time until the speed limit region, is determined. This speed increase is preferably calculated via an algorithm that depends on the motor vehicle. Here, the speed increase corresponds to the speed difference between the current vehicle speed and the maximum speed limit. Therefore, the maximum speed limit is obtained by adding the current speed and the speed increase.

[0010] In the next step, based on the current vehicle speed, the speed increase, and the distance to the start point of the speed limit area, deceleration is estimated to reach the speed limit value at the start point of the speed limit area. Here, if the estimated deceleration exceeds the deceleration limit value, the determined speed increase is decreased. Here, the deceleration limit value can be predetermined or can be changed by the driver within a specific limit. Similarly, it is also possible to decrease the deceleration limit value according to road conditions such as snow or rain, for example.

[0011] Here, this method can be executed using simple calculations and has the advantage that the amount of calculation for the execution of the method is reduced. Unnecessary braking and acceleration can also be additionally avoided. Thereby, fuel can be saved. In addition, since deceleration is maintained within a predetermined range, safety is enhanced. In addition, by using this method within the framework of a driving assistance system, the driving comfort for the driver is also enhanced.

[0012] In a preferred embodiment of the present invention, the speed increase is read from a characteristic diagram. In this characteristic diagram, for example, values regarding the speed increase can be stored with respect to the time until the speed limit area. Such a characteristic diagram can be stored, for example, on the factory side. By using such a characteristic diagram, the determination of the speed increase is greatly simplified. Thereby, the method can be executed more quickly and more easily. Furthermore, the required amount of calculation can be further significantly reduced.

[0013] In a further preferred embodiment of the present invention, based on the characteristic diagram, the decrease in the determined speed increase is calculated with respect to the estimated deceleration. In such a characteristic diagram, a speed decrease value can be stored with respect to the determined deceleration. Similarly, a coefficient between 0 and 1 can also be stored in the characteristic diagram. Here, this coefficient is multiplied by the speed increase, and the final speed increase is determined. Thereby, the final speed increase can be determined quickly and easily. By using the characteristic diagram, the calculation therefor is also greatly simplified.

[0014] Preferably, the characteristic diagram is selected in accordance with the selected driving mode of the vehicle. Here, the driver can select between various driving modes, such as a sports mode or a fuel-saving mode. Correspondingly, a stored corresponding characteristic diagram is used to execute the method. In contrast to the sports mode, in the fuel-saving mode, the speed increase is smaller and therefore the deceleration is also smaller. This allows the method to be adapted to the driver's wishes, thus significantly improving driving comfort.

[0015] In an advantageous development, a constant deceleration is assumed for the estimation of deceleration.Therefore, it is assumed that the vehicle always decelerates at a constant deceleration value based on the maximum limit speed.Although deceleration is not usually performed at a constant rate, the use of a constant deceleration simplifies the estimation of deceleration.This further significantly reduces the calculation effort.

[0016] Alternatively, predetermined deceleration functions for deceleration are used, which correspond to the actual deceleration. The use of such deceleration functions allows for a much more accurate determination of the deceleration. In addition, the maximum deceleration value that will occur can be better predicted.

[0017] In a further advantageous embodiment, the distance to the start of the speed limit zone is determined based on map data and / or sensor data and / or cloud data. The distance to the start of the speed limit zone can be determined in the map based on the current position, determined for example via GPS. Similarly, the distance to the speed limit zone can also be determined, for example, via a radar sensor. Such sensors are already equipped in many vehicles for other assistance systems, so no additional sensors are required. Additionally or alternatively, the distance can also be determined based on GPS data from the cloud. These options allow the distance to the speed limit zone to be determined in a simple and economical manner.

[0018] According to a preferred embodiment, the speed limit value is determined based on a legally predefined limit value and / or a limit value for each section. Here, the legally predefined limit value is, for example, a speed restriction or other speed predefined for a specific area. Here, this speed restriction may be displayed, for example, via a sign. Similarly, the limit value may be given, for example, by a curve, an uphill slope, or the road condition.

[0019] According to a further preferred embodiment, the speed limit value is determined based on map data and / or camera data and / or cloud data. Here, the speed limit value can be determined based on the value stored in the map. Similarly, the speed limit value can also be determined by a route such as a curve recognized in the map. Here, the curve radius or the maximum curve radius of the curve can be specified in the map. Then, the speed limit value is specified by this curve radius. Thereby, it can be ensured that there is no need to apply brakes unnecessarily within the curve, thereby improving safety. The speed limit values of the legal limit value and similarly the limit value for each section can also be called from the cloud. Thereby, the computational load of such a system can be reduced.

[0020] Advantageously, after the determination of the maximum speed limit, the vehicle accelerates from the current speed to the maximum speed limit, and then decelerates to the speed limit value by the start point of the speed limit area. By these steps provided within the framework of the driving assistance system, the driver's work is reduced, and thus the driving comfort is improved.

[0021] The object of the present invention is additionally solved by a control unit for a driving assistance system for controlling the driving adjustment of a motor vehicle, which is provided with an arithmetic unit for executing the method according to the present invention. Thereby, such a control unit can be incorporated into the motor vehicle, and thus the advantages described for this method can be achieved.

[0022] The above-described method can be implemented, in particular, for example, on a computer and thus can be embodied in software. Accordingly, the present invention also relates to a computer program comprising machine-readable instructions for causing one or more computers to perform the above-described method when executed on these computers. In this sense, a control device for a vehicle and an embedded system for a technical device, which can similarly execute the machine-readable instructions, can also be regarded as a computer.

[0023] Similarly, the present invention also relates to a machine-readable data carrier and / or a download product comprising a computer program. A download product is a digital product that can be transmitted via a data network, that is, a digital product that can be downloaded by a user of the data network and can be sold, for example, in an online shop for immediate download.

[0024] Exemplary embodiments of the present invention are shown in the drawings and will be described in more detail in the following description.

Brief Description of the Drawings

[0025] [Figure 1] It is a diagram showing an exemplary embodiment of the method according to the present invention.

Embodiments for Carrying Out the Invention

[0026] The figure shows an exemplary embodiment of the method according to the present invention. This method is used to determine the maximum speed v of the motor vehicle before the starting point of the speed limit area. In the first step A1, first, the current speed v of the motor vehicle is determined. Here, this speed v is directly determined, for example, from the current value of the motor vehicle. Similarly, the speed v can also be specified via the value of the GPS system. max In the first step A2, the speed limit value v of the approaching speed limit area is also determined in the same manner. Here, the speed limit value v

[0027] In the first step A2, the speed limit value v of the approaching speed limit area G is also determined in the same manner. Here, the speed limit value vG can be specified based on the legal value. Similarly, the speed limit value v G can also be determined via a speed limit sign recognized by a camera of the vehicle. The speed limit value v G can also be determined via the speed limit value v G input in the map. The speed limit value v G can also be additionally determined from the map based on, for example, the curve radius.

[0028] In the first step A3, the distance d z to the start point of the speed limit area is additionally determined. The distance d z can be specified from the map data, similar to the speed limit value v G . Alternatively or additionally, this distance d z can be determined via a sensor of the vehicle, such as a radar sensor.

[0029] Based on the current vehicle speed v, the speed limit value v G , and the distance d z to the start point of the speed limit area, in the next step B, the time t to the start point of the speed limit area is estimated. Here, the time t can be calculated, for example, based on the formula t = d z / ((v G + v) / 2). Since the time t is calculated based on the current speed v, this is merely an estimated value.

[0030] In the next step C, the speed increase Δv is specified based on the time t. For this purpose, for example, based on a characteristic diagram, the speed increase Δv is determined with respect to the time t. Then, in step D, based on this speed increase Δv, the required deceleration a G is estimated so that the speed becomes the speed limit value v v at the start point of the speed limit area. A constant deceleration can be assumed to estimate the deceleration a v , and thus the deceleration a v is obtained according to the following formula: a v =(v G 2-v 2 ) / (2 × d z ). Instead, the deceleration a can also be determined based on the characteristic diagram. v

[0031] Based on the deceleration a determined in this way, v this deceleration a v is compared with the deceleration limit value a G . Here, this deceleration limit value a G represents, for example, the maximum deceleration specified by driving comfort, the technical prerequisites of the vehicle, or the road conditions. If the determined deceleration a v is greater than the deceleration limit value a G , in the next step E, the determined speed increase Δv is decreased. The amount of decrease can be determined, for example, from the characteristic diagram.

[0032] After the speed increase Δv is decreased, or if the deceleration a v does not exceed the deceleration limit value a G , the vehicle is accelerated in the next step F to the limit speed v max obtained from the vehicle speed v and the speed increase Δv. In the subsequent step G, the vehicle is then decelerated to the speed limit value v G by the start point of the speed limit area.​

Claims

1. A method executed by a computer for determining the maximum speed limit (v ｍａｘ ) of a motor vehicle before the start point of a speed limit area, Current vehicle speed (v), speed limit value (v Ｇ ), and distance (d ｚ ) to the start point of the speed limit area, and steps (A1, A2, A3) for determining them A step (B) of estimating the time (t) until the speed limit area based on the previously determined current vehicle speed (v), the speed limit value (vG) of the speed limit area approaching ahead, and the distance (dz) to the start point of the speed limit area; A step (C) of specifying a speed increase (Δv) with respect to the current vehicle speed (v) depending on the time (t) until the speed limit area; Based on the current vehicle speed (v), the speed increase (Δv), and the distance (d) to the start point of the speed limit area ｚ ), estimating a deceleration (a Ｇ ) such that the speed limit value (v ｖ ) is reached at the start point of the speed limit area (step D); Said estimated deceleration (a ｖ ), when it exceeds a deceleration limit value (a Ｇ ), a step (E) of reducing said determined speed increase (Δv); In a method executed by a computer, comprising: The maximum speed limit (vmax) of the vehicle is obtained by adding the speed increase (Δv) to the current vehicle speed (v). A method executed by a computer.

2. The deceleration (a ｖ ) for which a constant deceleration is assumed for the estimation, characterized in that it is a method executed by a computer according to claim 1.

3. The deceleration (a ｖ ) is characterized in that a deceleration function predetermined with respect to the deceleration is used, and the method executed by the computer according to claim 1.

4. The distance (d ｚ ) to the start point of the speed limit area is determined based on map data and / or sensor data and / or cloud data, the method executed by a computer according to claim 1.

5. The speed limit value (v Ｇ ) is determined based on a legally predetermined limit value and / or a limit value for each section, the method executed by a computer according to claim 1, characterized in that.

6. The speed limit value (v Ｇ ) is determined based on map data and / or camera data and / or cloud data, the method executed by a computer according to claim 5.

7. After the determination of the maximum speed limit (v ｍａｘ ), the vehicle is accelerated from the current vehicle speed (v) to the maximum speed limit (F), and then decelerated to the speed limit value (v Ｇ ) by the time it reaches the start point of the speed limit area (G). The method according to claim 1, characterized in that it is executed by a computer.

8. A control unit for a driving assistance system for controlling the driving adjustment of a vehicle, comprising an arithmetic unit for executing the method executed by a computer according to any one of Claims 1 to 7.

9. A computer program for executing the method executed by a computer according to any one of Claims 1 to 7.

10. A machine-readable data carrier comprising the computer program according to Claim 9.

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