METHOD OF ROAD VEHICLE TRAJECTORY PLANNING

• US 20180059670A1
• Filed: 08/09/2017
• Published: 03/01/2018
• Est. Priority Date: 08/29/2016
• Status: Active Grant

• Current Assignee: Volvo Car Corporation (AB Volvo)
• Original Assignee: Volvo Car Corporation (AB Volvo)
• Inventors: NILSSON, Julia
• Granted Patent: US 10,860,027 B2
• Time in Patent Office: Days
• CPC Class Codes: B60W 2554/4049 Relationship among other objects, e.g. converging dynamic objects
• CPC Class Codes: B60W 2554/802 Longitudinal distance
• CPC Class Codes: B60W 2554/804 Relative longitudinal speed
• CPC Class Codes: B60W 2720/12 Lateral speed
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/095 Predicting travel path or likelihood of collision
• CPC Class Codes: B60W 30/0956 the prediction being responsive to traffic or environmental parameters
• CPC Class Codes: B60W 30/18163 Lane change; Overtaking manoeuvres
• CPC Class Codes: B60W 40/04 Traffic conditions
• CPC Class Codes: B60W 60/0016 of the vehicle or its occupants
• CPC Class Codes: B60W 60/00276 for two or more other traffic participants
• CPC Class Codes: G05D 1/0214 in accordance with safety or protection criteria, e.g. avoiding hazardous areas monitoring the location of vehicles within a certain area, e.g. forbidden or allowed areas, in traffic control systems for road vehicles G08G1/13
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

The present disclosure relates to a method of trajectory planning for maneuvers for an ego vehicle (E) equipped with a sensor systems, a prediction systems, a control system, and a decision-making system. The method includes determining possible lateral motion trajectories of a requested maneuver, longitudinal safety critical zones which correspond to each of the determined possible lateral motion trajectories, a longitudinal motion trajectory of the requested maneuver, lateral safety critical zones which correspond to the determined longitudinal motion trajectory of the requested maneuver, and a lateral motion trajectory of the requested maneuver. The present disclosure also relates to a driver assistance system arranged to perform the method and a vehicle including such a system.

Claims

1. A method of trajectory planning for maneuvers for an ego vehicle including a sensor system to measure a position of the vehicle on a road as well as relative positions and velocities of surrounding traffic participants and objects, a prediction system to estimate motion trajectories of surrounding traffic participants and objects over a defined time horizon, a control system capable of following a planned trajectory, and a decision-making system to provide a desired maneuver request, the method comprising:

using receding horizon control applying a finite prediction horizon for determining

possible lateral motion trajectories of a requested maneuver;

longitudinal safety critical zones which correspond to each of the determined possible lateral motion trajectories;

a longitudinal motion trajectory of the requested maneuver;

lateral safety critical zones which correspond to the determined longitudinal motion trajectory of the requested maneuver; and

a lateral motion trajectory of the requested maneuver.

2. The method according to claim 1 further comprising generating a set of possible lateral motion trajectories for the requested maneuver by initiating the lateral motion of the maneuver over a discrete time interval.

3. The method according to claim 2 wherein the discrete time interval is defined as i ∈

[1, . . . , min(N, N_g)−

(n_o+n_min)] where N denotes the prediction horizon, N_g denotes the time instance for which the targeted inter-vehicle traffic gap is no longer appropriate, n_o denotes the predicted time it takes for any surrounding vehicles constituting a tight inter-vehicle traffic gap to smoothly adjust their velocities in order to allow ego vehicle (E) to enter the gap, and n_min denotes the minimum time it takes for ego vehicle (E) to laterally move into the targeted inter-vehicle traffic gap.

4. The method according to claim 1 further comprising defining, when the set of possible lateral motion trajectories of the maneuver has been generated, a corresponding longitudinal safety critical zone for each relevant surrounding traffic participant and object as an appropriate miscellaneous shape, such as rectangular, triangular, or ellipsoid.

5. The method according to claim 4 further comprising defining, for each possible lateral motion trajectory of the requested maneuver and corresponding safety critical zones, the maximum and minimum bounds on the longitudinal position of ego vehicle (E) at each time instance as a longitudinal safety corridor, such that the longitudinal distance which ego vehicle (E) should maintain to each relevant surrounding traffic participant and object is defined with respect to each possible lateral motion trajectory of the requested maneuver and corresponding safety critical zones.

6. The method according to claim 1 further comprising determining, for each longitudinal safety corridor, if there exists a longitudinal trajectory which allow ego vehicle (E) to be positioned within the corridor over the prediction horizon and selecting, from the determined existing longitudinal trajectories for all longitudinal safety corridors, the most appropriate longitudinal trajectory.

7. The method according to claim 1 further comprising updating the safety critical zones of each relevant surrounding traffic participant and object according to the longitudinal motion of the requested maneuver utilizing the determined longitudinal motion trajectory of the requested maneuver.

8. The method according to claim 1 wherein determining a lateral motion trajectory of the requested maneuver further comprises formulating the lateral motion trajectory planning problem as a standard Quadratic Program optimization problem and solving this problem.

9. The method according to claim 1 further comprising utilizing at least part of one of the determined longitudinal and lateral motion trajectories of the requested maneuver to determine longitudinal and/or lateral control signals for control of the ego vehicle (E).

10. The method according to claim 9 further comprising combining the longitudinal and lateral control signals to a combined control signal for combined longitudinal and lateral control of the ego vehicle (E).

11. A driver assistance system configured to plan a trajectory for a maneuver for an ego vehicle, wherein the vehicle includes a sensor system to measure a vehicle position on a road as well as the relative positions and velocities of surrounding traffic participants and objects, a prediction system to estimate motion trajectories of the surrounding traffic participants and objects over a defined time horizon, a control system configured to follow a planned trajectory, and a decision-making system to provide a desired maneuver request, the driver assistance system configured to use receding horizon control applying a finite prediction horizon to:

determine possible lateral motion trajectories of a requested maneuver;

determine longitudinal safety critical zones which correspond to each of the determined possible lateral motion trajectories;

determine a longitudinal motion trajectory of the requested maneuver;

determine lateral safety critical zones which correspond to the determined longitudinal motion trajectory of the requested maneuver; and

determine a lateral motion trajectory of the requested maneuver.

12. The driver assistance system according to claim 11 wherein at least part of one of the determined longitudinal and lateral motion trajectories of the requested maneuver is utilized for one or more of the following:

decide if a maneuver should be initiated or aborted;

perform a maneuver, autonomously or driver supervised;

provide driver guidance for performing a maneuver; and

provide driver warning and/or information when a maneuver could and should not be performed.

13. A vehicle comprising the driver assistance system according to claim 11.

14. A method of trajectory planning for maneuvers for an ego vehicle including a sensor system to measure a position of the vehicle on a road as well as relative positions and velocities of surrounding traffic participants and objects, a prediction system to estimate motion trajectories of the surrounding traffic participants and objects over a defined time horizon, a control system configured to follow a planned trajectory, and a decision-making system to provide a desired maneuver request, the method comprising:

determining possible lateral motion trajectories of a requested maneuver;

determining longitudinal safety critical zones which correspond to each of the determined possible lateral motion trajectories;

determining a longitudinal motion trajectory of the requested maneuver;

determining lateral safety critical zones which correspond to the determined longitudinal motion trajectory of the requested maneuver; and

determining a lateral motion trajectory of the requested maneuver.