Method for determining an avoidance trajectory for a vehicle - Patents.com

Abstract

Method for determining avoidance trajectories for vehicles 1. A method for determining an avoidance trajectory for a vehicle (1) to avoid one or more objects (8, 9), comprising: a) recognizing a first object (8) in a predicted trajectory (10) of said vehicle (1); b) determining a left lateral avoidance distance (65) with respect to said first object (8); c) determining a right lateral avoidance distance (66) with respect to said first object (8); d) selecting the smaller of the left lateral avoidance distance (65) and the right lateral avoidance distance (66) as a first ideal lateral avoidance distance; and e) determining a first ideal avoidance trajectory (91) along which the vehicle (1) passes through the object (8) according to the first ideal lateral avoidance distance; A method comprising:

Description

[Technical field]

[0001] The present invention relates to a method, and a computer program, for determining an avoidance trajectory for a vehicle avoiding one or more objects. Summary of the Invention

[0002] Currently, there are collision mitigation braking systems (CMBS) and autonomous emergency braking systems that assist the driver of a vehicle to prevent or mitigate situations that may result in a collision with an object, such as a pedestrian, an animal, or another vehicle, or with other objects on the roadway. A collision may be caused by an inattentive or distracted driver or poor visibility. Some of these systems also have the ability to steer the vehicle away from objects detected in its path to avoid an imminent collision. There are only a limited number of such systems available, and the ability of these systems to steer the vehicle away from objects is currently limited.

[0003] US2015 / 0120137A1 relates to a method for calculating a virtual target path around a target object, including providing scan points that identify the object to be detected.

[0004] It is an object of the present invention to provide an improved method for avoiding one or more objects on the trajectory of a vehicle.

[0005] Thus, there is provided a method for determining an avoidance trajectory for a vehicle to avoid one or more objects, the method comprising: a) recognizing a first object in a predicted trajectory of a vehicle; b) determining a left lateral avoidance distance relative to the first object; c) determining a right lateral avoidance distance relative to the first object; d) selecting the smaller of the left lateral avoidance distance and the right lateral avoidance distance as a first ideal lateral avoidance distance; e) determining a first ideal avoidance trajectory along which the vehicle passes through the object according to the first ideal lateral avoidance distance; Includes.

[0006] This method has the advantage of determining an avoidance trajectory that allows the vehicle to pass the object with a minimal amount of additional movement, thereby maintaining vehicle stability during the evasive maneuver.

[0007] The "left lateral avoidance distance" is the lateral distance from the central longitudinal axis of the vehicle to the left outer edge of the first object in plan view (preferably plus a safety distance). The "right lateral avoidance distance" is the lateral distance from the central longitudinal axis of the vehicle to the right outer edge of the first object in plan view (preferably plus a safety distance).

[0008] After determining the first ideal avoidance trajectory, the trajectory is displayed to the driver on a vehicle HMI (Human-Machine-Interface) such as a screen and / or a control unit of the vehicle assists the driver in driving along the trajectory (so-called driving assistance function). Examples of driving assistance functions include more highly automated systems configured to enable semi-automated or fully automated driving of the vehicle with any of the automation levels 1 to 5 defined by the Society of Automotive Engineers (SAE), such as Adaptive Cruise Control (ACC), Lane Keep Assist (LKA), Traffic Jam Assist (TJA), Highway Assist (HWA), Traffic Jam Pilot (TJP), Collision Mitigation Braking System (CMBS), etc.

[0009] A control unit, for example a central electronic control unit of a vehicle, may be configured to perform some or all of the method steps described herein. The control unit may be implemented using hardware and / or software and may include a microprocessor, RAM, ROM, etc.

[0010] According to an embodiment, the method comprises: rejecting the ideal lateral avoidance distance in favor of the other one of the left lateral avoidance distance and the right lateral avoidance distance, which is subsequently determined to be a second ideal lateral avoidance distance, if a second object is detected on the first ideal avoidance trajectory; determining a second ideal avoidance trajectory along which the vehicle passes through the object in response to the second ideal lateral avoidance distance; Further includes:

[0011] The method helps to increase safety by checking if there is a second object on the ideal avoidance trajectory, so that a collision with the second object can be avoided during the avoidance steering system. After determining the second ideal avoidance trajectory, the trajectory is displayed to the driver on the vehicle HMI and / or the vehicle's control unit assists the driver in driving along the trajectory.

[0012] According to an embodiment, the method comprises: determining one or more virtual lines; and / or determining a first and / or a second ideal avoidance trajectory according to the first and / or the second ideal lateral avoidance distance and the one or more virtual lines; Further includes:

[0013] This step helps to guide the vehicle in the absence of any other objects. The virtual line indicates the corridor through which the vehicle passes during the avoidance maneuver. The virtual line or lines may be determined, for example, using a virtual width to indicate the width of the vehicle.

[0014] According to an embodiment, the method comprises: comparing the measured distance between the vehicle and the object to a minimum expected longitudinal distance, which is a predetermined distance between the vehicle and the object, and initiating a predetermined response based on the vehicle's current speed, steering capabilities, and deceleration capabilities; Further includes:

[0015] Depending on the distance between the vehicle and the object, it is necessary to determine whether a certain response, such as braking or steering, is necessary or can be made safely, which helps to increase vehicle safety and stability when approaching and possibly overtaking objects.

[0016] According to an embodiment, the method comprises: repeating the step of comparing the measured distance between the vehicle and the object with a minimum expected longitudinal distance until the minimum expected longitudinal distance is equal to or less than a first predetermined distance, at which point the vehicle initiates partial braking; Further includes:

[0017] This step contributes to vehicle safety because, below the first predetermined distance, it is no longer possible to steer to effect an evasive maneuver at the vehicle's current speed while maintaining lateral vehicle stability, which helps to avoid sudden, hard-to-control swerves or skids.

[0018] According to an embodiment, the method comprises: repeating the step of comparing the measured distance between the vehicle and the object with a minimum expected longitudinal distance until the minimum expected longitudinal distance is equal to or less than a second predetermined distance, at which point the vehicle initiates full braking; Further includes:

[0019] This step contributes to vehicle safety, because below the second predetermined distance it is no longer possible to perform an avoidance maneuver by steering at the vehicle's current speed while maintaining lateral vehicle stability. Thus, at this point partial braking is no longer sufficient. Full braking must be applied to maintain vehicle safety.

[0020] According to an embodiment, the method comprises: repeating the step of comparing the measured distance between the vehicle and the object with the minimum predicted longitudinal distance until the minimum predicted longitudinal distance is equal to or less than a third predetermined distance, the third predetermined distance being a distance of a point of no return, the point of no return being determined as the point at which the object can no longer be avoided by steering; Further includes:

[0021] If the vehicle is closer to the object, i.e., if the vehicle passes the third predetermined distance, the remaining distance between the vehicle and the object becomes too short to perform a lateral avoidance maneuver. In this case, lateral stability cannot be maintained when performing an avoidance maneuver. If lateral stability is lost, the consequences may be more serious than the possibility of a collision with the object. Therefore, this step helps maintain vehicle safety.

[0022] According to an embodiment, the method comprises: performing assisted steering according to the first ideal avoidance trajectory or the second ideal avoidance trajectory when it is detected that the driver is steering in the direction of the first ideal avoidance trajectory or the second ideal avoidance trajectory; When it is detected that the driver is not steering in the direction of the first ideal avoidance trajectory or the second ideal avoidance trajectory, if the vehicle has reached the first predetermined distance but not reached the third predetermined distance, performing automatic steering according to the first ideal avoidance trajectory or the second ideal avoidance trajectory; deactivating an emergency braking routine; Further includes:

[0023] This part of the method helps to perform an evasive maneuver, whereby vehicle stability can be maintained while avoiding an object, either under driver control with assistance from an evasive steering system or under automatic control by the vehicle's computer. In both cases, since it is difficult to ensure vehicle stability during an evasive maneuver, vehicle stability is ensured by deactivating the sudden braking when it is applied. These steps help to maintain vehicle stability during the evasive maneuver.

[0024] According to an embodiment, the method comprises: the first object or the second object is recognized by an environmental sensor, the environmental sensor preferably including at least one of a camera, a RADAR sensor, a LIDAR sensor, a laser scanner, an infrared sensor, a stereo camera, and an ultrasonic sensor; Further includes:

[0025] In one variant, the computer program product comprises instructions that cause a computer to carry out the above-mentioned method when the program is executed by a computer.

[0026] Further possible implementations or alternative solutions of the invention include combinations of the features described above or below with respect to the embodiments, as well as combinations not explicitly mentioned here. Also, a person skilled in the art may add individual or isolated aspects and features to the most basic form of the invention. [Brief description of the drawings]

[0027] Further embodiments, features and advantages of the present invention will become apparent from the following description and dependent claims, taken in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 shows, in a side view, a vehicle equipped with a camera for detecting objects. [Diagram 2] FIG. 2 shows, in a top view, a vehicle approaching another vehicle. [Diagram 3] FIG. 3 shows, in a top view, a vehicle approaching another vehicle in a situation where the further vehicle blocks one avoidance trajectory. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In the drawings, unless otherwise noted, like reference numbers indicate like or functionally equivalent elements.

[0029] 1 is a schematic side view of a vehicle 1 approaching an object 8. The vehicle is equipped with a camera 3. The camera 3 is oriented in the direction of the arrow R so that it can detect the object 8 in the predicted trajectory of the vehicle 1.

[0030] 2 is a top view showing a vehicle 1 approaching an object 8 (here also "first object"), in this example another vehicle. The vehicle 1 has a planned trajectory 10, which is a predicted vehicle path as calculated by a control unit 4, for example based on data from environmental sensors, vehicle odometry and a GPS navigation system. Based on information from the camera 3, the control unit 4 (for example the vehicle's central electronic control unit - "ECU") detects the left and right edges of the object 8 in the predicted trajectory 10 and assigns to each of these edges a virtual line 21, 22 running parallel to the predicted trajectory 10. Based on these virtual lines 21, 22, the control unit 4 determines an overlap for each of the left and right sides of the vehicle 1. The left overlap is indicated by reference numeral 61 and the right overlap by reference numeral 62.

[0031] It should be noted that the camera 3 is only an example of an environmental sensor used to detect objects around the vehicle 1. Other environmental sensors that can be used are RADAR sensors, LIDAR sensors, laser scanners, infrared sensors, stereo cameras and ultrasonic sensors. Furthermore, it is also possible that several of these types of sensors are used. In case several types of sensors are used, the signals of the various sensors are combined and evaluated by the control unit 4 in order to detect objects such as the first object 8 or other objects in the environment of the vehicle 1. Depending on the type of sensor, the mounting position of the sensor is determined, for example near the top of the windshield or at another position on the vehicle, so that the sensor can scan an area in the path of the vehicle.

[0032] Preferably, the vehicle 1 passes the object 8 not only with its outer edges on the imaginary lines 21 and 22, but also with a safety distance indicated by reference numeral 41 for the left side of the object 8 and with a safety distance indicated by reference numeral 42 for the right side of the object 8. The left overlap 61 and the left safety distance 41 are added to obtain the left lateral avoidance distance 65. The right overlap 62 and the right safety distance 42 are added to obtain the right lateral avoidance distance 66.

[0033] Taking into account the safety distances 41, 42, the control unit 4 calculates a pair of imaginary lines labelled 31 and 32. Using these imaginary lines, the control unit 4 determines ideal possible avoidance trajectories 91 and 92 on which the vehicle 1 may pass the object 8 on the left or right side. The selection between the possible avoidance trajectories 91 and 92 is usually done by selecting the shorter of the trajectories 91 and 92. In FIG. 2, this is the trajectory 91, which is therefore determined as the ideal avoidance trajectory 95. However, it is possible that the object 9 shown in FIG. 3 (here also the "second object") is detected by the camera 3. If the vehicle 1 were to move along the trajectory 91 as shown in FIG. 2 and FIG. 3, a collision with the object 9 would occur, as indicated by X in FIG. 3. Therefore, the control unit 4 discards the shorter avoidance trajectory 91, which was selected as the ideal avoidance trajectory 95 in FIG. 2. Instead, the control unit 4 will select the trajectory 92 as the ideal avoidance trajectory 95, as shown in FIG.

[0034] In Fig. 2, reference numeral 71 denotes the front end of the vehicle 1, and the rear end of the object 8 is indicated by a dashed line 81. The current distance between the rear end 81 and the front end 71 is indicated by 75. To safely pass the object 8, the vehicle 1 needs to pass / cover the current distance 75 (up to the dashed line 82), but in addition a longitudinal safety distance indicated by the dashed line 82 needs to be taken into account by the control unit 4. This longitudinal safety distance is determined by the relative speed between the vehicle 1 and the object 8, which may be another vehicle moving at a slower speed than the vehicle 1. From the above, it should be clear that if no further object 9 is detected by the camera 3 on the trajectory 91, this trajectory 91 will be maintained as an ideal avoidance trajectory 95, as shown in Fig. 2.

[0035] After determining the ideal avoidance trajectory 95, the control unit 4 calculates the predicted minimum steering angle required for the vehicle to avoid the object 8 by steering. Determine the longitudinal distance. This minimum longitudinal distance is calculated using the current speeds of the vehicle 1 and the object 8 and using a given lateral acceleration that will occur during the steering maneuver. For this purpose, there are also further distances calculated by the control unit 4. One of these distances between the object 8 and the vehicle 1 is indicated by the line 72. At this distance from the object 8, the vehicle 1 is caused to perform partial braking by the host. At a closer distance from the object 8, indicated by the number 73, the host causes the vehicle 1 to initiate full braking. The closest distance to the object 8 as shown in Figures 2 and 3 is labelled 74 and indicates the so-called return limit distance. If the vehicle 1 reaches the line 74, it will no longer be possible to avoid a collision by lateral steering.

[0036] After determining the ideal lateral avoidance distance (but possibly before determining the ideal avoidance trajectory 95), the control unit 4 determines a virtual line 23 (which may correspond to the virtual outer edge of the vehicle 1) in the absence of any other detected objects such as lane markers, round boundaries, vehicles, barriers, pavements, as shown in FIG. 2. The virtual line 23 is determined using a virtual width 43 measured from the virtual line 31. The virtual width 43 is indicative of, for example, the width of the vehicle 1 and other parameters as required. The virtual width 43 is stored in the memory of the control unit 4 as a predetermined value. It may be calculated by considering the current speed and the predicted speed of the vehicle 1 along the ideal avoidance trajectory. The virtual line 23 is shown in FIG. 2 as not parallel to the ideal avoidance trajectory 95, because it also depends on the current speed of the vehicle 1. When the vehicle 1 arrives at the dashed line 81, the vehicle speed will be the lowest. Correspondingly, the virtual width 43 can be made smaller, because it is easier to maintain the lateral stability of the vehicle at low speeds. At other points in the trajectory, the virtual width 43 needs to be larger because the vehicle will be traveling faster and therefore it will be more difficult to maintain lateral stability, or it can be calculated based on other detected objects such as vehicles, lane markers, other boundaries, barriers, or pavement.

[0037] Then, the control unit 4 calculates or adapts an ideal avoidance trajectory 95 based on the virtual lines 23, 31. In a further step, the control unit 4 calculates, based on the calculated or adapted ideal avoidance trajectory 91, 92, 95, the steering required to perform an evasive lateral steering maneuver and ensure lateral vehicle stability by controlling the vehicle 1 within the corridor bounded on the inside by the virtual line 31 in Figure 2 and on the outside by the virtual line 23.

[0038] The driver may already be steering the vehicle 1 in the same direction as the ideal avoidance trajectory 95. In this case, the control unit 4 will assist the driver with a driving assistance function to ensure that the vehicle 1 stays within the corridor bounded by the virtual lines 31 and 23. Another possibility is that the control unit 4 no longer only performs an assistance function in the absence of steering by the driver, but starts to fully automatically steer the vehicle 1 along the ideal avoidance trajectory 95 before the return limit point 74 is reached. In either case of assisted or fully automatic steering along the ideal avoidance trajectory 95, emergency braking is ineffective.

[0039] Although the present invention has been described based on preferred embodiments, it will be apparent to one skilled in the art that modifications are possible in all embodiments. [Explanation of symbols]

[0040] Reference sign 1 vehicle 3. Camera 4. Control Unit 8 1st object 9 Second object 10 Predicted trajectory 21-23 Virtual Line 31 Left lateral avoidance line 32 Right lateral avoidance line 41 Left safety distance 42 Right safety distance 43 Virtual Width 61 Left overlap 62 Right overlap 65 Left lateral avoidance distance 66 Right lateral avoidance distance 71 Position of the front end of the vehicle 72 Partial Brake Start Position 73 Start position of all brakes 74 Return Limit 75 Distance Measured 81 Position of rear end of object 82 Safe distance from first object 91 1st ideal avoidance trajectory 92 Second ideal avoidance trajectory 95 Ideal avoidance trajectory S1-S18 steps

Claims

1. 1. A method for determining an avoidance trajectory for a vehicle (1) to avoid one or more objects (8, 9), comprising: a) recognising a first object (8) in a predicted trajectory (10) of said vehicle (1), detecting a left edge and a right edge of said object (8) in said predicted trajectory (10), assigning to each of said edges a virtual line (21, 22) running parallel to said predicted trajectory (10) and determining an overlap for each of the left and right sides of the vehicle (1) based on said virtual lines (21, 22); b) determining a left lateral avoidance distance (65) for said first object (8), where a left overlap (61) and a left safe distance (41) are added to obtain said left lateral avoidance distance (65); c) determining a right lateral avoidance distance (66) with respect to said first object (8), where a right overlap (62) and a right safety distance (42) are added to obtain said right lateral avoidance distance (66); d) selecting the smaller of the left lateral avoidance distance (65) and the right lateral avoidance distance (66) as a first ideal lateral avoidance distance; and e) determining a first ideal avoidance trajectory (91) along which said vehicle (1) passes said object (8) as a function of said first ideal lateral avoidance distance; The method includes:

2. rejecting the first ideal lateral avoidance distance in favor of the other of the left lateral avoidance distance (65) and the right lateral avoidance distance (66), which is different from the smaller one selected as the first ideal lateral avoidance distance and which is a second ideal lateral avoidance distance, if a second object (9) is detected on the first ideal avoidance trajectory (91); and determining a second ideal avoidance trajectory along which the vehicle (1) passes through the object (8) in response to the second ideal lateral avoidance distance; The method of claim 1 further comprising:

3. determining one or more virtual lines (23, 31, 32); and / or determining a first ideal avoidance trajectory and / or a second ideal avoidance trajectory (92) according to the first ideal lateral avoidance distance and / or the second ideal lateral avoidance distance and the one or more virtual lines (23, 31, 32); The method of claim 1 or 2, further comprising:

4. comparing the measured distance (75) between the vehicle (1) and the object (8) with a predetermined distance between the vehicle (1) and the object (8) to initiate a predetermined response based on the current speed, steering capabilities and deceleration capabilities of the vehicle (1). The method according to any one of claims 1 to 3, further comprising:

5. Repeating the step of comparing the measured distance (75) between the vehicle (1) and the object (8) with the predetermined distance until the predetermined distance is equal to or smaller than a first predetermined distance (72) at which the vehicle (1) will initiate partial braking. The method of claim 4 further comprising:

6. Repeating the step of comparing the measured distance (75) between the vehicle (1) and the object (8) with the predetermined distance until the predetermined distance is equal to or less than a second predetermined distance (73) at which the vehicle (1) will initiate full braking. The method of claim 4 or 5, further comprising:

7. Repeating the step of comparing the measured distance (75) between the vehicle (1) and the object (8) with the predetermined distance until the predetermined distance is equal to or smaller than a third predetermined distance (74), which is the distance of a limit return point, the limit return point being defined as the point at which the object (8) can no longer be avoided by steering. The method according to any one of claims 4 to 6.

8. performing assisted steering based on the first ideal avoidance trajectory or the second ideal avoidance trajectory (91, 92) when it is detected that the driver is steering in the direction of the first ideal avoidance trajectory or the second ideal avoidance trajectory (91, 92); When it is detected that the driver does not steer in the direction of the first ideal avoidance trajectory or the second ideal avoidance trajectory (91, 92), if the vehicle (1) reaches the first predetermined distance (72) but does not reach the third predetermined distance (74), performing automatic steering based on the first ideal avoidance trajectory or the second ideal avoidance trajectory; and Deactivating the emergency braking routine The method of claim 7 further comprising:

9. The first object (8) or the second object (9) is recognized by an environmental sensor, the environmental sensor including at least one of a camera (3), a RADAR sensor, a LIDAR sensor, a laser scanner, an infrared sensor, a stereo camera, and an ultrasonic sensor. The method according to any one of claims 1 to 8.

10. A computer program product comprising instructions which, when said program is executed by a computer, cause said computer to carry out the method of one of claims 1 to 9.

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