DE102019201697A1 - Method for stopping an autonomous vehicle - Google Patents

Abstract

In a method (V) for stopping an autonomous vehicle (1), the vehicle (1) moves along a target trajectory (2). A position determination system (8) of the vehicle (1) fails. The position determination system (8) is set up to determine a position of the vehicle (1) by means of a global navigation satellite system (GNSS). A target speed (3) of the vehicle (1) is set at 0 km / h. A current position (4) of the vehicle (1) is calculated using odometry. Starting from the calculated current position (4), the vehicle (1) is moved on the target trajectory (2) until it stops on the target trajectory (2).

Description

The present invention relates to a method for defining a work area for a vehicle having the features of claim 1, a control device having the features of claim 7, a computer program product having the features of claim 8, and a vehicle having the features of claim 9.

Today's autonomous vehicles require a valid GNSS signal for navigation. An updated GNSS position is only available after a relatively long time window. To bridge this time window, today's navigation solutions are i. d. Usually equipped with an acceleration sensor. However, if the GNSS signal fails over a longer period of time (greater than one to two seconds) or if the system suddenly works inaccurately (e.g. due to disturbances in the ionosphere), the vehicle can no longer be located and must be transferred to a safe operating state become. Therefore, in the event of a GNSS failure, operation of the autonomous vehicle is no longer possible. If the vehicle is not brought to a stop on a planned trajectory due to a GNSS failure, collisions, personal injury or damage to agricultural machines and vehicles can occur in the field.

Out DE 10 2006 054 346 A1 a mobile satellite-based navigation device and a method for determining the geographical position of a vehicle are known.

Based on the prior art, the present invention is based on the object of proposing a method for stopping an autonomous vehicle which can be used even if a position determination fails.

Based on the above object, the present invention proposes a method for defining a work area for a vehicle according to claim 1, a control device according to claim 7, a computer program product according to claim 8, and a vehicle according to claim 9. Further advantageous refinements and developments emerge from the subclaims.

In a method for stopping an autonomous vehicle, the vehicle moving along a target trajectory. A position determination system of the vehicle fails. The position determination system is set up to determine a position of the vehicle by means of a global navigation satellite system. A target speed of the vehicle is set at 0 km / h. A current position of the vehicle is calculated using odometry. Starting from the calculated current position, the vehicle continues to move on the target trajectory until it stops on the target trajectory.

The vehicle is an off-road utility vehicle, e.g. B. an agricultural or forestry vehicle, namely an agricultural machine, a construction machine, an industrial truck, a snow groomer, a mining vehicle, a cleaning machine, or another commercial vehicle. The vehicle is preferably an agricultural vehicle.

The vehicle is designed in such a way that it can drive autonomously and that it can perform other automated functions if necessary. For example, automated functions can be: spreading seed, grit, bulk material, fertilizer, herbicides, pesticides, fungicides or the like; harvesting, pruning or grubbing up plants or the like; turning, loosening or removing soil; a transportation of goods. These automated functions and autonomous driving are preferably carried out by the vehicle only within one work area.

The off-road area refers to the area that is away from roads and paths, for example areas used for agriculture or forestry, construction site areas, company premises or the like.

The work area is the area within which the vehicle should be located in order to do its work. For example, if it is an agricultural vehicle, the work area can be an agricultural area to be worked on, e.g. B. be a field or a plantation. The work area has a boundary that separates it from the surroundings. This limit can be determined, for example, by a property boundary, field boundary or corridor boundary.

The vehicle moves along a target trajectory. This target trajectory can, for example, have been planned by means of a control device of the vehicle. This can, for example, carry out trajectory planning using software. In other words, the target trajectory represents the trajectory along which the vehicle is to move. It is also planned which sections of the target trajectory can be driven with which speed, with which acceleration and with which steering angle.

Position data for the vehicle are required to plan and follow the target trajectory. This position data is determined by means of the position determination system of the vehicle. The vehicle's positioning system uses the global navigation satellite system ( GNSS ). This allows, for example, GPS coordinates of the vehicle to be determined. It is therefore possible to clearly determine the global position of the vehicle. Furthermore, the GNSS determines the coordinates of the target trajectory that the vehicle is to drive. On the basis of this, the vehicle can be controlled by means of the control device in such a way that it moves along the target trajectory.

A failure of the positioning system can be caused, for example, by a fault in the positioning system itself. Alternatively, the failure of the positioning system can be caused by a malfunction of the GNSS caused. Alternatively, the failure of the positioning system may be due to a transmission failure GNSS caused. The consequence of the failure is that the global position of the vehicle is determined by means of the GNSS is no longer determinable. As a result, safe traversing of the target trajectory is no longer guaranteed.

As soon as the position determination system fails and it is no longer possible to determine the global position of the vehicle, the target speed of the vehicle is set to 0 km / h. This is done by means of the control device of the vehicle. The control device is connected to a drive system of the vehicle. More precisely, the control device is connected to an actuator system of the drive system of the vehicle. This connection is such that data and signal exchange can take place. The connection can, for example, be wireless or wired. For this purpose, the control device, like the individual actuators of the drive system, has at least one interface via which the data and signal exchange can take place.

The control device is set up to control the actuator system of the drive system of the vehicle. The drive system of the vehicle has, for example, a motor unit, e.g. B. an electric motor, an internal combustion engine or the like, a transmission, a steering system, and a braking system. The control device can control the actuation of these elements just mentioned such that, for example, a drive torque is made available, that a steering angle is set on the wheels of the vehicle, that the vehicle is braked or the like empower them to drive autonomously.

In order to fix the speed of the vehicle to 0 km / h, the control device thus controls the actuator system of the drive system, so that the vehicle is braked and no more drive torque is provided. However, until the vehicle stops, it covers a certain braking distance depending on its initial speed. This braking distance is to be selected such that it lies on the target trajectory. It is therefore necessary to determine the current position of the vehicle despite the failure of the positioning system.

A current position of the vehicle is calculated using odometry. Using odometry, the current position can be inferred from the data determined for the movement of the vehicle. This movement data can be used to determine the speed at which the vehicle is moving in which direction. This in turn can be used to infer coordinates of the vehicle. The last known coordinates of the vehicle are used to calculate where the vehicle will be after a certain period of time after the position determination system has failed and will be there until it stops. This calculation can be carried out, for example, by means of the control device, which uses a computer program product for this purpose.

Starting from the calculated current position, the vehicle continues to move on the target trajectory until it stops on the target trajectory. The coordinates of the target trajectory to be traversed are known from the trajectory planning. The control device accordingly controls the actuator system of the drive system of the vehicle in such a way that it reduces its speed to 0 km / h, but at the same time does not leave the target trajectory. For this purpose, the control device can, for example, adapt a steering angle of the vehicle.

An advantage of the presented method is that even if the position determination system fails, the vehicle is kept on the target trajectory until it comes to a standstill. This prevents damage or accidents in the vicinity of the target trajectory of the vehicle. For example, a lane is not left in an agricultural vehicle working on an agricultural area, so that no damage to the seeds occurs. The coordinates calculated using odometry are less precise than those using GNSS certain coordinates, but are sufficient for stopping the vehicle safely.

According to a further embodiment, the current position of the vehicle is calculated using a kinematic vehicle model. This kinematic vehicle model is based on data from the steering angle sensor system of the vehicle. Furthermore, the kinematic vehicle model is based on data the speed sensor system of the vehicle, data of the speed sensor system of the vehicle and / or data of the acceleration sensor system of the vehicle. Suitable steering angle sensors, speed sensors, speed sensors and acceleration sensors are known from the prior art.

The distance traveled and the distance traveled can be calculated from the data relating to the speed, acceleration or wheel speeds of the vehicle. An orientation of the vehicle can be calculated from the data on the steering angle of the vehicle. Data on the steering angle and data on the wheel speed are preferably used. In other words, the kinematic vehicle model can be used to calculate the direction in which the vehicle is traveling.

This makes it possible to determine the current position of the vehicle in a simple manner independently of the position determination system. It is advantageous that existing sensors are used to determine the current position of the vehicle.

According to a further embodiment, the current position of the vehicle is calculated using the data of an inertial measuring unit. The inertial measurement unit is known as the inertial measurement unit (IMU). This inertial measuring unit provides data relating to the acceleration of the vehicle in all three spatial directions, as well as data relating to a rotational movement of the vehicle in all three spatial directions. Thus, the orientation of the vehicle in space and the movement of the vehicle can be concluded. From this, the current position of the vehicle can be determined in a simple manner independently of the position determination system.

According to a further embodiment, the current position of the vehicle is calculated using radar, lidar or visual odometry. Data from a radar system, a lidar system, an ultrasound system, an infrared system and / or a camera system is used. These systems can be summarized under the generic term of imaging sensor systems. On the basis of the data from these systems, a distance between the vehicle and objects in the vicinity can be determined. Starting from this distance, which changes as a result of the movement of the vehicle, the current position of the vehicle can be calculated using odometry.

According to a further embodiment, the vehicle is additionally stopped within the work area. In other words, the vehicle is both kept on the target trajectory and stopped within the work area. For example, the work area can be delimited from an environment by means of additional delimitations, for example by means of a physical or virtual fence. This additional delimitation can be detected, for example, by means of in-vehicle sensors, e.g. B. by means of imaging sensor systems. Alternatively, the work area can only be defined using coordinates. These are known to the control device of the vehicle, for example they are stored in a memory.

In order to stop the vehicle within the work area, the control device controls the actuator system of the drive system of the vehicle on the basis of the current calculated position of the vehicle and on the basis of the data for delimiting the work area. For example, a stronger braking of the vehicle can be initiated so that the work area is not left. This is advantageous if the failure of the positioning system occurs close to the boundary of the work area. This can prevent the vehicle from presenting an accident risk to the surroundings outside the work area.

According to a further embodiment, the calculated current position of the vehicle is checked for plausibility by means of trilateration based on radio signals. For example, the vehicle can have a communication device by means of which the vehicle can communicate via radio signals with a central office, with a cloud, with other vehicles (C2C) and / or with an infrastructure (C21). This can be called C2X communication. A radio standard is used for this communication, for example WLAN, LTE, UMTS, Zig-Bee, Bluetooth or the like. The communication device has at least one interface by means of which it is connected to the control device of the vehicle. This connection is such that data and signal exchange can take place.

So that communication can be guaranteed, have radio networks, e.g. B. the mobile network, several transmitters that are spaced from each other.

The vehicle is thereby connected to the transmitters by means of its communication device. The position of the vehicle in relation to at least three of these transmitters can be determined by the communication device itself or by the control device using trilateration. If the global position of the transmitter is also known, e.g. B. in GPS coordinates, the current position of the vehicle can be estimated. This makes it possible to to check the current position of the vehicle, which was calculated by odometry.

The control device for the vehicle can be connected to a drive system of the vehicle, to at least one sensor system of the vehicle and to a position determination system of the vehicle. The control device has means which are set up to stop the vehicle according to the method steps which have already been described in the previous description.

The control device has several interfaces via which the connections between the control device and further elements can be established. The control device is connected to the actuator system of the drive system, so that the control device can control it. This has already been described in the previous description. The control device can be designed, for example, as an ECU or domain ECU.

The control device can be connected to the at least one sensor system of the vehicle. The at least one sensor system can include a steering angle sensor system, an acceleration sensor system, a speed sensor system, a speed sensor system, or an imaging sensor system for environment detection, e.g. B. have a radar, lidar, or camera system. Of course, the vehicle can have a combination of these sensor systems just mentioned. The connection between the control device and the at least one sensor system is such that data and signal exchange can take place. The connections can be wireless or wired.

Furthermore, the control device can be connected to the position determination system. In regular operation, the position determination system supplies the coordinates of the vehicle to the control device, so that trajectory planning and traversing of the target trajectory can take place. This has already been described in the previous description. In addition, the control device can be connected to the communication device of the vehicle.

The control device has means which are set up to stop the vehicle according to the method steps which have already been described in the previous description. These means can be, for example, a computer program product, by means of which the method steps that are required to stop the vehicle can be carried out. These are: determining the failure of the positioning system; lowering the speed to 0km / h; calculating the current position of the vehicle using odometry; moving the vehicle on the target trajectory until the vehicle stops.

The computer program product comprises instructions which, when the control device executes the program, execute the method which has already been described in the previous description. The computer program product uses program code, which can be embodied on a data carrier or as a downloadable data stream.

A vehicle has a control device which has already been described in the previous description. The vehicle also has a position determination system, at least one sensor system and a drive system. The control device is connected to the position determination system, to the sensor system and to the drive system. In addition, the vehicle can have a communication device.

In addition to the sensor system already described, the at least one sensor system can have one radar sensor or one lidar sensor per wheel. These sensors can be arranged behind each wheel in the direction of travel. The data obtained in this way make it possible to determine the vehicle's own movement. Thus, it would be possible to compensate for inaccuracies in odometry, e.g. B. because of unevenness in the work area z. B. can occur due to vegetation. In addition, a float angle of the vehicle could also be determined.

• 1 eine schematische Darstellung eines Verfahrens nach einem Ausführungsbeispiel,
• 2 eine schematische Darstellung eines Fahrzeugs in einem Arbeitsbereich, das ein Verfahren nach dem Ausführungsbeispiel aus 1 nutzt.

Various exemplary embodiments and details of the invention are described in more detail with reference to the figures explained below. Show it:

• 1 1 shows a schematic illustration of a method according to an exemplary embodiment,
• 2nd is a schematic representation of a vehicle in a work area, the method according to the embodiment 1 uses.

1 shows a schematic representation of a method V according to an embodiment. In a first step 101 the vehicle moves autonomously on a target trajectory, which was planned by means of a control device of the vehicle. During this step 101 the global position of the vehicle can be uniquely determined by means of a position determination system of the vehicle, since the position determination system is still working correctly. The coordinates of the vehicle are therefore known at all times.

In a second step 102 a failure of the positioning system is determined. For example, from one GNSS Position data is no longer received or the positioning system is defective. As soon as current coordinates of the vehicle can no longer be determined using the position determination system, it is necessary to bring the vehicle to a safe stop.

In a first part of a third step 103a A target speed of the vehicle is set by the control device of the vehicle to Okm / h. The control device therefore controls a drive system of the vehicle so that braking is initiated.

In a second part of the third step that runs simultaneously 103b A current position of the vehicle is calculated using odometry based on data on the movement of the vehicle. These data are determined using at least one sensor system of the vehicle. The current position is calculated, for example, using data relating to the wheel speeds and data relating to a steering angle of the vehicle.

In a fourth step 104 the vehicle is controlled by means of the control device on the basis of the calculated current position of the vehicle and on the basis of the known target trajectory in such a way that it comes to a standstill on the target trajectory at a safe stop position. The control device thus controls the drive system of the vehicle in such a way that its longitudinal and transverse guidance is adapted in such a way that it continues to move on the target trajectory during the entire braking process until it finally stops.

2nd a schematic representation of a vehicle 1 in a work area 5 , which is a method according to the embodiment 1 uses. The work area 5 is an agricultural area that has a boundary 12th is delimited from the environment. The vehicle 1 moves within the work area 5 autonomous along its target trajectory 2nd . This target trajectory 2nd lies on a predefined lane 11 within the work area 5 .

The vehicle 1 has a drive system 7 , a control device 6 , a positioning system 8th and a sensor system 9 on. The control device 6 is with the positioning system 8th connected so that data and signal exchange can take place. The control device 6 is with the drive system 6 connected so that data and signal exchange can take place. The control device 6 is with the sensor system 9 connected so that data and signal exchange can take place.

The positioning system 8th serves a global position of the vehicle 1 to investigate. This is usually with the GNSS connected. Here it is GNSS however not reachable. This can change the global position of the vehicle 1 and thus the coordinates of the vehicle 1 cannot be determined.

The sensor system 9 has a wheel speed sensor system and a steering angle sensor system. The control device can use the data from these sensors 6 the current position using odometry 4th of the vehicle 1 to calculate. This makes it possible for the vehicle 1 on the target trajectory 2nd to keep. Alternatively, the current position can be calculated using the data of an IMU. Again, alternatively, the current position can be calculated using radar, lidar or visual odometry.

The control device 6 controls the drive system 7 of the vehicle 1 such that the vehicle 1 is braked and at the same time on the target trajectory 2nd remains. That is, a longitudinal guide and a transverse guide of the vehicle 1 will be adapted. The vehicle 1 thus moves in the direction of travel for so long 3rd continue until it is in the safe stop position 10 comes to a standstill. This ensures that the vehicle 1 due to the failure of the positioning system 8th still comes to a standstill.

Reference list

1

vehicle

2nd

Target trajectory

3rd

Direction of travel

4th

actual position

5

Workspace

6

Control device

7

Drive system

8th

Positioning system

9

Sensor system

10th

Stop position

11

lane

12th

Limitation

101

first step

102

second step

103a

third step first part

103b

third step second part

104

fourth step

105

fifth step

V

Procedure

GNSS

global navigation satellite system

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102006054346 A1 [0003]

Claims (9)

Method (V) for stopping an autonomous vehicle (1), wherein - the vehicle (1) moves along a target trajectory (2), a failure of a position determination system (8) of the vehicle (1), which is set up to determine a position of the vehicle (1) by means of a global navigation satellite system (GNSS), occurs, a target speed (3) of the vehicle (1) is set to 0 km / h, a current position (4) of the vehicle (1) is calculated by means of odometry, - Starting from the calculated current position (4), the vehicle (1) is moved further on the target trajectory (2) until it stops on the target trajectory (2). Method (V) according to Claim 1 The current position (4) of the vehicle (1) is calculated using a kinematic vehicle model. Method (V) according to one of the preceding claims, wherein the current position (4) of the vehicle (1) is calculated using data from an inertial measuring unit. Method (V) according to one of the preceding claims, wherein the current position (4) of the vehicle (1) is calculated by means of radar, lidar or visual odometry. Method (V) according to one of the preceding claims, wherein the vehicle (1) is additionally stopped within a work area (5). Method (V) according to one of the preceding claims, wherein the calculated current position (4) of the vehicle (1) is checked for plausibility by means of trilateration on the basis of radio signals. Control device (6) for a vehicle (1), the control device (6) with a drive system (7) of the vehicle (1), with at least one sensor system (9) of the vehicle (1) and with a position determination system (8) of the vehicle (1) can be connected, the control device (6) having means which are set up to move the vehicle (1) according to the method steps from one of the Claims 1 to 6 to stop. Computer program product, comprising commands that are executed when the program is executed by a control device (6) Claim 7 , the procedure according to one of the Claims 1 to 6 To run. Vehicle (1) comprising a control device (6) Claim 7 , a position determination system (8), a sensor system (9) and a drive system (7), the control device (6) being connected to the position determination system (8), to the sensor system (9) and to the drive system (7).

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