Obstacle detection when a driverless motor vehicle starts moving from a parked position

Abstract

Obstacle detection device for detecting obstacles when a motor vehicle capable of driving away from a parking position without a driver, with a vehicle function for driverless parking and / or driving, wherein the obstacle detection device is configured, - before the motor vehicle is parked at the parking position, a first driving resistance quantity relating to the driving resistance until the parking position is reached (a') stoer ) to determine, - the first driving resistance quantity (a' stoer ) to save, - from starting off at the parking position in the opposite direction of travel, a second driving resistance quantity relating to the driving resistance from starting off at the parking position (a') stoer ; a'' stoer ) to determine and to compare the second driving resistance quantity with the first driving resistance quantity or with a driving resistance quantity derived from the first driving resistance quantity, and - depending on this, to detect an obstacle that was not present when parking.

Description

[0001] The invention relates to an obstacle detection device for detecting obstacles when a motor vehicle starts moving from a parked position without a driver (in particular without passengers). The invention further relates to a driverless motor vehicle with such an obstacle detection device and a corresponding method for detecting obstacles.

[0002] With autonomous valet parking, a vehicle user can leave their vehicle in a handover zone, and the vehicle will drive itself to a parking space in a parking area, e.g., in a parking garage. Later, the vehicle user can request the vehicle again, e.g., via smartphone or car key, and the vehicle will drive autonomously from its parking position to the handover zone without an occupant.

[0003] Similarly, in a driverless driving service, an autonomous vehicle can be requested by a vehicle user, e.g. via smartphone, which then drives driverless from a parking position to the vehicle user or to a defined handover zone.

[0004] In such scenarios, the vehicle, without an occupant, must start its engine, drive off, and then travel the distance to the requesting party. The decision as to whether it is safe to drive off after a potentially lengthy period of inactivity must therefore be made solely by the vehicle itself. For example, a person or animal might have approached the vehicle during the inactivity period and could then be in the immediate danger zone of the vehicle when it starts moving (e.g., directly around or underneath the vehicle).

[0005] The first few meters when starting off are particularly relevant here.

[0006] Standard environmental sensors in typical installation locations are unsuitable for obstacle detection in the immediate danger zone of the vehicle. One possible solution would be to install additional environmental sensors in different locations and / or to modify existing sensors to detect obstacles in this immediate danger zone. This is complex, involves additional costs, and is fraught with numerous, primarily technical, challenges.

[0007] The publication DE 101 14 273 A1 describes in paragraph

[0005] the behavior of a vehicle with two-wheel drive and open differential when the driving resistance increases due to an incline or obstacle.

[0008] In the publication DE 10 2015 112 311 A1, a driver assistance system for parking a motor vehicle is described in which contact of at least one wheel with a curb is detected by means of a change in the engine speed.

[0009] The object of the invention is to provide an obstacle detection device for the immediate danger zone of the motor vehicle and a corresponding method which does not require any further environmental sensors adapted for the immediate danger zone.

[0010] The problem is solved by the features of the independent claims. Advantageous embodiments are described in the dependent claims. It should be noted that additional features of a dependent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0011] A first aspect of the invention relates to an obstacle detection device for detecting new obstacles (i.e., obstacles not present when the vehicle was parked) when a motor vehicle capable of moving from a parked position without a driver (especially without passengers) starts moving. The vehicle function is, for example, a valet parking function.

[0012] The obstacle detection device is configured to perform various tasks described below. This is typically accomplished by means of an electronic control unit, which may also be distributed across several control units. The control unit can comprise one or more processors that operate according to the invention, controlled by one or more software programs.

[0013] The obstacle detection device is designed to determine, before the motor vehicle is parked at the parking position, a driving resistance value relating to the driving resistance until the parking position is reached (hereinafter referred to as "first driving resistance value"), in particular to determine a driving resistance value characteristic of the driving resistance until the parking position is reached.

[0014] In this process, preferably before the motor vehicle is parked at the parking position, a first profile (e.g. over distance or time) of the first driving resistance parameter is determined until the parking position is reached, for example for a predetermined distance before the parking position (e.g. x meters).

[0015] The initial driving resistance value is to be stored in such a way that, after the vehicle is switched off and the engine is turned off, the information about the first determined driving resistance value is not lost, but is available again when the vehicle is started again later. A suitable storage medium is used for this purpose.

[0016] If, later upon request, the vehicle moves into the parking position in the opposite direction to that used during the previous parking maneuver (preferably initially following the same path as when parking), a driving resistance parameter (hereinafter referred to as the "second driving resistance parameter") is determined from the moment the vehicle starts moving from the parking position. This parameter is characteristic of the driving resistance from the moment the vehicle starts moving from the parking position. For example, the profile of this second driving resistance parameter (e.g., over distance or time) is determined from the moment the vehicle starts moving from the parking position.

[0017] The obstacle detection device is configured to compare the second driving resistance value with the first driving resistance value or with a driving resistance value derived from the stored first driving resistance value.

[0018] Depending on the comparison, an unexpected deviation can indicate the presence of a new obstacle in the immediate danger zone of the motor vehicle, especially if the deviation exceeds a certain degree or the second driving resistance parameter is increased by a certain amount compared to the reference parameter.

[0019] Existing obstacles on the road during parking, such as a drainage ditch, have a comparable effect on the first and second driving resistance parameters and are therefore not recognized as a new obstacle.

[0020] For example, the vehicle (e.g., via sensors in the drivetrain) determines the current driving resistance during the last few meters before parking and stores this data, resulting in a driving resistance curve. When starting off again after parking, the same distance is initially covered, preferably very slowly. If significant deviations occur between the driving resistance curve and the (inverse) stored driving resistance curve, particularly if the driving resistance curve determined during restarting is higher than the stored driving resistance, this indicates the presence of a new obstacle in the immediate danger zone of the vehicle (e.g., underneath the vehicle) that was not present when it was parked. The vehicle then initiates emergency braking.

[0021] For example, if the obstacle detection system detects an obstacle, the vehicle can inform an external recipient directly (e.g., via a Bluetooth connection) or indirectly (e.g., via a signal to a backend system). This recipient could be the person requesting the vehicle or a designated contact person (e.g., a parking garage employee) via their smartphone, key fob, or other communication device. After verifying the obstacle situation at the vehicle, the recipient can then confirm the safety of the vehicle continuing its journey via the communication device or an input device directly on the vehicle itself, provided it was a false alarm or the obstacle no longer exists, allowing the vehicle to proceed safely.

[0022] The vehicle preferably starts moving from its parked position without an occupant. However, it is also conceivable that an occupant is present in the vehicle when it starts moving, but that occupant does not act as the driver (e.g., because the occupant is not ready or able to drive due to their abilities or their position in the vehicle, or because the vehicle does not provide for manual driving and only drives fully autonomously).

[0023] The first and second driving resistance parameters can be characteristic of the total driving resistance or of one or more subcomponents of the driving resistance, for example, gradient resistance and rolling resistance without taking into account air resistance and acceleration resistance.

[0024] The comparison described above could also be carried out separately for several components of the driving resistance, for example, if the curves for the gradient resistance before stopping and when starting again and the curves for the rolling resistance before stopping and when starting again are determined and then compared separately.

[0025] As explained above, for each driving resistance parameter, a curve of the value of the respective driving resistance parameter is used, varying over the driving time or distance. For comparison of the curves, for example, the curve of the first driving resistance parameter is compared with the inverse curve of the second driving resistance parameter over time or distance, or alternatively, the inverse curve of the first driving resistance parameter over time or distance is compared with the determined curve of the second driving resistance parameter.

[0026] The driving resistance parameter can, for example, be a disturbance parameter (e.g., in the form of an estimated disturbance acceleration) of the controlled system of a vehicle speed control loop (concerning the vehicle's function for driverless driving), estimated via a disturbance parameter estimator, or derived from it. Preferably, the course of the estimated disturbance acceleration during parking is then recorded.

[0027] It is known to reintroduce an estimated disturbance variable of the controlled system (e.g., in the form of an estimated disturbance acceleration) into the control loop to compensate for disturbances caused by the controlled system (e.g., by superimposing an acceleration control variable determined in the controller with an estimated disturbance acceleration). This is described, for example, in DE 10 2013 210 672 A1. This document describes a disturbance estimator for estimating a disturbance acceleration, which calculates an acceleration as a disturbance variable of the controlled system based on the current actual velocity and the currently set drive torque. In the disturbance estimator, for example, a current acceleration is determined from the current actual velocity by differentiation and this current acceleration is compared with the current torque converted into an acceleration. From this comparison, the disturbance acceleration is then calculated using a suitable transfer function.Provided that the current acceleration and the current drive torque match, the current value of the disturbance acceleration is zero.

[0028] Preferably, the disturbance variable used is an acceleration or a quantity that can be converted into an acceleration (e.g., torque, force).

[0029] It is advantageous to consider the influence of a vehicle temperature difference between a warm vehicle before parking and a cold vehicle when starting off on the first and second driving resistance parameters. For example, when starting off with a cold vehicle, the drive response is generally more sluggish, and therefore the driving resistance is greater compared to parking with a warm vehicle. To account for the influence of the temperature difference, the first or second driving resistance parameter can be adjusted (for example, using a linear function y = a · x + b) so that this influence is compensated for.

[0030] Similarly, the influence of an outside temperature difference before parking and when subsequently starting off can preferably be taken into account on the first and second driving resistance parameters. For example, if the outside temperature is lower when starting off than it was when approaching the parking position, this results in an increase in driving resistance compared to the situation without a change in outside temperature. To account for the influence of the outside temperature difference, the first or second driving resistance parameter can be adjusted (for example, using a linear function y = a · x + b) so that this influence is compensated for.

[0031] A second aspect of the invention relates to an automated motor vehicle with a vehicle function for driverless parking and / or driving (e.g., a valet parking vehicle function), which includes an obstacle detection device according to the first aspect of the invention. The vehicle is configured to start moving autonomously from a parking position without a driver, and in particular without an occupant (for example, initiated by a person requesting the vehicle), and to initiate emergency braking upon starting off if an obstacle is detected by the obstacle detection device.

[0032] It is advantageous if, in the event of an obstacle being detected by the obstacle detection device, the vehicle directly or indirectly informs an external receiver about this.

[0033] In this case, it is further advantageous if the vehicle is set up to receive confirmation from the external receiver to continue driving after the emergency stop, and to continue driving in response to the confirmation.

[0034] A third aspect of the invention relates to a method for detecting obstacles when a motor vehicle capable of driving away from a parking position without a driver, particularly without an occupant, and equipped with a vehicle function for driverless parking and / or driving, starts moving. The method comprises the following steps: - before parking the motor vehicle at the parking position, determining an initial driving resistance value relating to the driving resistance until the parking position is reached; - Storing the first driving resistance value; - from starting off at the parking position in the opposite direction of travel, determining a second driving resistance quantity relating to the driving resistance from starting off at the parking position and comparing the second driving resistance quantity with the first driving resistance quantity or a driving resistance quantity derived from the first driving resistance quantity, and - Recognizing a new obstacle depending on this.

[0035] The foregoing descriptions of the obstacle detection device according to the first aspect of the invention also apply accordingly to the method according to the third aspect of the invention. Advantageous embodiments of the method according to the invention not explicitly described here or in the claims correspond to the advantageous embodiments of the obstacle detection device according to the invention described above or in the claims.

[0036] The invention is described below with reference to an exemplary embodiment and the accompanying drawings. These show: Fig. 1 an exemplary functioning of an embodiment of an obstacle detection device according to the invention; Fig. 2 an exemplary parking situation with an exemplary course of a driving resistance quantity when approaching the parking position and with an exemplary course of a driving resistance quantity when subsequently starting off from the parking position without a new obstacle; Fig. 3. An exemplary parking situation with an exemplary course of a driving resistance quantity when approaching the parking position and with an exemplary course of a driving resistance quantity when subsequently starting off from the parking position with a new obstacle; and Fig. 4 an exemplary speed control loop with disturbance estimator.

[0037] In Fig. Figure 1 is an exemplary functioning of an embodiment for an obstacle detection device according to the invention in connection with an exemplary automated parking function / driving function (e.g. valet parking function) for driverless driving with automated longitudinal and lateral guidance of a motor vehicle.

[0038] In step 100, the vehicle automatically drives to a parking position using the automated vehicle function; for example, the vehicle is parked in a parking space in a parking garage. During the approach to the parking position, the profile of a driving resistance parameter is determined over a certain distance to the parking position. This driving resistance parameter could, for example, be the profile of an estimated disturbance acceleration a'. stoer over a distance traveled, which is later related to Fig. 4 is explained.

[0039] After reaching the parking position, in step 110 the curve of the driving resistance value over the distance is reversed, so that the driving resistance value curves from x = 0 (parking point) to x = x max (e.g., 10 m). The inverse curve of the driving resistance value over the distance is stored, and the vehicle is switched off.

[0040] In Fig. 2b is an example of the reversed course 10 of the disturbance acceleration a' stoer represented over the path length x, specifically for a in Fig. 2a shows an exemplary elevation profile of the road surface up to the point where the parking position x = 0 is reached. According to Fig. 2a. When approaching the parking position x = 0, the vehicle must overcome a slight incline in the road surface; furthermore, a depression (e.g., a rain gutter) is present in the elevation profile. The estimated disturbance acceleration a' stoerAs a measure of driving resistance, it initially shows a positive value due to the slight uphill incline when parking. Upon entering the recess, the disturbance acceleration a' decreases. stoer (in Fig. 2b even to a negative value). When driving out of the recess, the disturbance acceleration a' stoer rises sharply, only to fall back to approximately the initial value after leaving the hollow.

[0041] In query 120, it is repeatedly checked whether the parked vehicle has been requested, for example via an application on a smartphone or via a vehicle key.

[0042] If the vehicle request was confirmed in step 130, the vehicle, without an occupant, automatically starts moving very slowly towards the transfer zone. During this very slow acceleration, a curve of the driving resistance quantity is determined over the distance x. The driving resistance quantity determined during acceleration could, for example, be a curve of an estimated disturbance acceleration a'. stoer over the distance x during restart. An example curve 11 of the estimated disturbance acceleration a' stoer is in Fig. 2c is shown. Due to the reversed direction of travel when starting off compared to when parking, the profile of the road surface has an inverse effect, i.e., a section of the road surface that accelerates when parking has a decelerating effect when starting off again, and vice versa.

[0043] To determine the course of the driving resistance quantity (here: the estimated disturbance acceleration a') stoer ) when approaching the parking position of the vehicle Fig. 2b with the course of the driving resistance quantity (here: the estimated disturbance acceleration a' stoer ) when restarting Fig. To compare 2c, the course of the driving resistance quantity (here: the estimated disturbance acceleration a') will be stoer ) during restarting while recording the profile, successively into a profile 12 of a converted driving resistance quantity (here: the converted disturbance acceleration a'') stoer ) converted (for example with a'' stoer := - a' stoerThe conversion takes into account the different directions of travel when approaching the parking position and when starting again. The driving resistance value determined for starting again is thus converted into a driving resistance value with the reverse direction of travel. Similarly, the stored profile of the driving resistance value for approaching the parking position could also be converted.

[0044] It is advantageous to also consider the influence of a vehicle temperature difference between a warm vehicle when parked and a cold vehicle when later starting off on the driving resistance quantity (here: the estimated disturbance acceleration a'). stoer ) is taken into account. To account for the influence of the temperature difference, for example, the conversion (here to a'') stoer ) this temperature influence is also compensated for.

[0045] Similarly, the influence of an outside temperature difference when parking and when subsequently starting off can also be considered in relation to the driving resistance (here: estimated disturbance acceleration a'). stoer ) must be taken into account. For example, to account for the influence of the outside temperature difference, the conversion (here to a'') is adjusted accordingly. stoer ) this temperature influence is also compensated for.

[0046] Furthermore, deceleration before stopping, especially via a brake, and acceleration from the start of driving via the drive have different effects on the driving resistance magnitude (here: estimated disturbance acceleration a'). stoer ). This influence can also be seen, for example, in the conversion (here: to a''). stoer ) can also be compensated.

[0047] The course 10 of the driving resistance quantity (here: the estimated disturbance quantity a') stoer) before the motor vehicle is parked, the curve 12 of the converted driving resistance quantity (here: the estimated disturbance quantity a'') can then be used. stoer ) can be compared. Provided that no new obstacles have been added to the vehicle between the vehicle being parked and the vehicle being started again, the course 10 of the driving resistance quantity (here: the estimated disturbance variable a') should be . stoer ) before the motor vehicle is parked, with the curve 12 of the converted driving resistance quantity (here: the estimated disturbance quantity a'') stoer ) depending on the quality of the compensation above, they should approximately match. However, if a sufficiently large deviation is found in the two curves 10 and 12 during the comparison, this indicates a new obstacle.

[0048] The comparison is performed point by point for the same waypoint x. For example, in the example of Fig. 2 successively for the current waypoint x i the value a'stör (x i ) the disturbance acceleration a' stoer before parking the motor vehicle with the value a'' stör (x i ) the converted disturbance variable a'' stoer compared.

[0049] In the case of Fig. 2 is the value a' stoer (x i ) the disturbance variable a' stoer before parking the motor vehicle with the converted value a'' stoer (x i ) the disturbance variable a'' stoer when restarting for all x i approximately the same (compare) Fig. 2d and Fig. 2b).

[0050] If the difference between the two comparison values ​​for waypoint x i a' stoer (x i ), a'' stoer (x i ) exceeds a certain measure L in terms of amount (abs (a') stoer (x i ) - a'' stoer (x iIf the value is )) > L), this is recognized as an indication of a new obstacle and an automated emergency stop is triggered (see step 160). Such a situation occurs in Fig. 3 shown. The driving surface FU in Fig. 3a additionally includes a new obstacle that only enters the immediate danger zone after the vehicle has been parked, but before the vehicle has started moving again.

[0051] The curves 11, 12 of the disturbance acceleration a' stoer (x i ), a'' stoer (x i ) after restarting in Fig. 3c and Fig. 3d exhibits an additional characteristic for the new obstacle, which is reflected in the course of the disturbance acceleration a' stoer is not included when approaching the parking position. Therefore, during restarting, the difference between the two comparison values ​​a' exceeds the threshold when the obstacle is reached. stoer (x i ) out of Fig. 3b and a'' stoer (x i ) out of Fig. 3d. The magnitude of the obstacle exceeds the specified dimension L, so that this is recognized as an indication of a new obstacle, and an emergency stop is triggered. Furthermore, the requester is informed by a corresponding signal. Only when the vehicle receives a confirmation signal initiated by the requester (see query 170), which authorizes further travel, does the vehicle proceed.

[0052] In Fig. Figure 4 schematically illustrates an exemplary linear velocity control loop with disturbance estimator. The control loop includes a controller R, which has a control deviation Δv = v soll - v ist between a target vehicle speed specified by the parking or driving system v soll and a vehicle's actual speed v ist receives and generates an output signal depending on this.

[0053] Furthermore, a disturbance variable estimator (SGS) is provided, which depends on the current actual velocity v.ist and the estimated current moment M ist an acceleration a' stoer as a disturbance variable. In the disturbance variable estimator SGS, for example, the current actual velocity v is used. ist By differentiating, a current acceleration is determined, and this current acceleration is compared to the current moment M converted into an acceleration. ist The disturbance variable a' is compared. From this comparison, the disturbance variable a' is then determined via a suitable transfer characteristic. stoer estimated. Provided that the current acceleration and the current torque M ist The value of the estimated disturbance variable a' fits together. stoer equal to zero. By subtracting the disturbance variable a' stoer The target acceleration a is derived from the target acceleration at the output of the controller R. soll calculated. From the target acceleration a soll A target torque M is set in block 20. soll calculated. The target torque M sollThe torque is then split into a target torque for the drive and a target torque for the brake (not shown).

[0054] The disturbance a' estimated via the SGS disturbance estimator stoer is an estimate for the disturbance variable a acting via the controlled system RS stoer The disturbance variable a' stoer It can be used not only for controlling vehicle speed, but also, as described above, as a driving resistance parameter for obstacle detection. The disturbance estimator SGS estimates the total disturbances acting on the vehicle as a controlled system, which influence the vehicle's motion. The parameter a stoerThe disturbances acting on the control system are summarized from the perspective of the physical model and represented in an acceleration quantity that takes into account, among other things, air resistance, rolling resistance, gradient resistance and frictions in the drive train acting as additional driving resistance.

Claims

[1] Obstacle detection device for detecting obstacles when a motor vehicle capable of starting from a parking position without a driver and having a vehicle function for driverless parking and / or driving, wherein the obstacle detection device is configured, - before the motor vehicle is parked at the parking position, a first driving resistance quantity relating to the driving resistance until the parking position is reached (a') stoer ) to determine, - the first driving resistance quantity (a' stoer ) to save, - from starting off at the parking position in the opposite direction of travel, a second driving resistance quantity relating to the driving resistance from starting off at the parking position (a') stoer ; a'' stoer ) to determine and to compare the second driving resistance quantity with the first driving resistance quantity or with a driving resistance quantity derived from the first driving resistance quantity, and - depending on this, to detect an obstacle that was not present when parking. [2] Obstacle detection device according to claim 1, wherein the obstacle detection device is configured, - before parking the motor vehicle at the parking position, a curve (10) of the first driving resistance quantity (a') stoer ) to determine the parking position, which is then saved, until the parking position is reached, - from starting at the parking position, a profile (11, 12) of the second driving resistance quantity (a' stoer ; a'' stoer to determine. [3] Obstacle detection device according to one of the preceding claims, wherein the first and second driving resistance variables are an estimated disturbance variable of the controlled system of a vehicle speed control loop relating to the vehicle function for driverless driving or are derived from the disturbance variable. [4] Obstacle detection device according to claim 3, wherein the disturbance variable is a disturbance acceleration (a' stoer ) is. [5] Obstacle detection device according to one of the preceding claims, which is configured to determine a driving resistance value (a') for a given direction of travel. stoer ) into a driving resistance quantity (a'') stoer ) to convert for the opposite direction of travel. [6] Obstacle detection device according to one of the preceding claims, which is configured to take into account the influence of a vehicle temperature difference between a warm motor vehicle before being parked and a cold motor vehicle when starting off on the first and second driving resistance variables. [7] Obstacle detection device according to one of the preceding claims, which is configured to take into account the influence of an outside temperature difference before parking and when starting off on the first and second driving resistance variables. [8] Automated motor vehicle with a vehicle function for driverless parking and / or driving, comprising an obstacle detection device according to one of the preceding claims, and which is equipped, - to drive away from a parking position without a driver, - to initiate an emergency stop when starting off if an obstacle is detected via the obstacle detection device. [9] Automated motor vehicle according to claim 8, wherein the vehicle function for driverless parking and / or driving is a valet parking function. [10] Automated motor vehicle according to one of claims 8 or 9, wherein the motor vehicle is equipped, - in the event of an obstacle detected by the obstacle detection device, to inform a receiver external to the vehicle directly or indirectly, - to receive confirmation from the external receiver to continue driving after the emergency braking, and - to continue driving in response to the confirmation to proceed. [11] Method for detecting obstacles when a driverless motor vehicle is moving from a parking position and has a vehicle function for driverless parking and / or driving, comprising the steps: - before parking the motor vehicle at the parking position, determining a first driving resistance quantity relating to the driving resistance until reaching the parking position (a' stoer ); - Storing the first driving resistance value (a') stoer ); - from starting off at the parking position in the opposite direction of travel, determining a second driving resistance quantity relating to the driving resistance from starting off at the parking position (a' stoer ; a'' stoer ) and comparing the second driving resistance quantity with the first driving resistance quantity or a driving resistance quantity derived from the first driving resistance quantity; and - Detecting an obstacle that was not present when the motor vehicle was parked, depending on this.

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