Systems and methods for trajectory planning in an autonomous vehicle using different fixed durations for steering and speed parameters

• US 10,037,037 B1
• Filed: 02/10/2017
• Issued: 07/31/2018
• Est. Priority Date: 01/18/2017
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Nagasaka, Naoki, Kamata, Nobuhide, Harada, Masahiro
• Primary Examiner(s): Jeanglaude, Gertrude Arthur
• Application Number:
  US15/430,311
• Publication Number:
  US 20180203456A1
• Time in Patent Office: 536 Days
• Field of Search: 701 25, 701 36, 701 93
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2552/00 Input parameters relating to infrastructure
• CPC Class Codes: B60W 2552/05 Type of road, e.g. motorways, local streets, paved or unpaved roads
• CPC Class Codes: B60W 2552/10 Number of lanes
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2552/30 Road curve radius
• CPC Class Codes: B60W 2552/53 Road markings, e.g. lane marker or crosswalk
• CPC Class Codes: B60W 2554/00 Input parameters relating to objects
• CPC Class Codes: B60W 2554/20 Static objects
• CPC Class Codes: B60W 2554/4026 Cycles
• CPC Class Codes: B60W 2554/4029 Pedestrians
• CPC Class Codes: B60W 2554/4041 Position
• CPC Class Codes: B60W 2554/60 Traversable objects, e.g. speed bumps or curbs
• CPC Class Codes: B60W 2554/80 Spatial relation or speed relative to objects
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2555/60 Traffic rules, e.g. speed limits or right of way
• CPC Class Codes: B60W 2556/00 Input parameters relating to data
• CPC Class Codes: B60W 2710/207 : Steering angle of wheels
• CPC Class Codes: B60W 2720/10 : Longitudinal speed
• CPC Class Codes: B60W 2720/103 : Speed profile
• 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 30/18009 : related to particular drive situations
• CPC Class Codes: B60W 30/18163 : Lane change; Overtaking manoeuvres
• CPC Class Codes: B60W 50/0097 : Predicting future conditions
• CPC Class Codes: B60W 60/0016 : of the vehicle or its occupants
• CPC Class Codes: G05D 1/0223 : involving speed control of the vehicle vehicle fittings for automatically controlling, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator B60K31/00

Abstract

System, methods, and other embodiments described herein relate to autonomously controlling a vehicle according to a trajectory plan. In one embodiment, a method includes updating, upon traveling over at least a portion of a current segment of a roadway, the trajectory plan for a subsequent segment of the roadway by setting a fixed portion of the trajectory plan to include: (i) a steering parameter to be fixed for a first duration of time and (ii) a speed parameter to be fixed for a second duration of time. The first duration of time and the second duration of time are of different lengths. The method includes computing input controls for autonomously controlling the vehicle according to the fixed portion of the trajectory plan. The method includes controlling the vehicle according to the input controls over the subsequent segment of the roadway.

Claims

1. A trajectory planning system for autonomously controlling a vehicle according to a trajectory plan, comprising:

one or more processors;

a memory communicably coupled to the one or more processors and storing;

a planning module including instructions that when executed by the one or more processors cause the one or more processors to update, upon traveling over at least a portion of a current segment of a roadway, the trajectory plan for a subsequent segment of the roadway by setting a fixed portion of the trajectory plan to include;

(i) a steering parameter to be fixed for a first duration of time and (ii) a speed parameter to be fixed for a second duration of time, wherein the first duration of time and the second duration of time are of different lengths; and

a control module including instructions that when executed by the one or more processors cause the one or more processors to compute input controls for autonomously controlling the vehicle according to the fixed portion of the trajectory plan, and

wherein the control module includes instructions to control the vehicle over the subsequent segment of the roadway according to the input controls.

2. The trajectory planning system of claim 1, wherein the second duration of time for the speed parameter is shorter than the first duration of time for the steering parameter.

3. The trajectory planning system of claim 1, wherein the first duration of time for the steering parameter is shorter than the second duration of time of the speed parameter.

4. The trajectory planning system of claim 1, wherein the planning module includes instructions to dynamically select relative lengths of time for the first duration and the second duration according to trajectory data that identifies a present context of the vehicle.

5. The trajectory planning system of claim 4, wherein the control module includes instructions to collect, from sensors of the vehicle, the trajectory data that identifies a present context according to operating characteristics of the vehicle and environmental characteristics about surroundings of the vehicle.

6. The trajectory planning system of claim 1, wherein the trajectory plan defines a course along the roadway for autonomously controlling the vehicle, wherein the first duration and the second duration are partially coextensive according to an offset between the first duration and the second duration, and wherein the fixed portion of the trajectory plan is unmodifiable once set to maintain consistent operation of the vehicle along the course on the roadway.

7. The trajectory planning system of claim 1, wherein the planning module further includes instructions to update the trajectory plan by adjusting target points in the trajectory plan beyond a current segment prior to fixing the first duration and the second duration for the steering parameter and the speed parameter.

8. The trajectory planning system of claim 1, wherein the control module further includes instructions to compute the input controls by computing the input controls from the fixed portion at discrete points in time along the trajectory plan, wherein the input controls include at least steering inputs, accelerator inputs, and braking inputs.

9. A non-transitory computer-readable medium storing instructions that when executed by one or more processors cause the one or more processors to:

update, upon traveling over at least a portion of a current segment of a roadway, a trajectory plan for a subsequent segment of the roadway by setting a fixed portion of the trajectory plan to include;

(i) a steering parameter to be fixed for a first duration of time and (ii) a speed parameter to be fixed for a second duration of time, wherein the first duration of time and the second duration of time are of different lengths;

compute input controls for autonomously controlling a vehicle according to the fixed portion of the trajectory plan; and

control the vehicle over the subsequent segment of the roadway according to the input controls.

10. The non-transitory computer-readable medium of claim 9, wherein the second duration of time for the speed parameter is shorter than the first duration of time for the steering parameter.

11. The non-transitory computer-readable medium of claim 9, wherein the first duration of time for the steering parameter is shorter than the second duration of time of the speed parameter.

12. The non-transitory computer-readable medium of claim 9, wherein the trajectory plan defines a course along the roadway for autonomously controlling the vehicle, wherein the first duration and the second duration are partially coextensive according to an offset between the first duration and the second duration, and wherein the fixed portion of the trajectory plan is unmodifiable once set to maintain consistent operation of the vehicle along the course on the roadway.

13. The non-transitory computer-readable medium of claim 9, wherein the instructions to update the trajectory plan include instructions to adjust target points in the trajectory plan beyond a current segment prior to fixing the first duration and the second duration for the steering parameter and the speed parameter.

14. A method of autonomously controlling a vehicle according to a trajectory plan, comprising:

updating, upon traveling over at least a portion of a current segment of a roadway, the trajectory plan for a subsequent segment of the roadway by setting a fixed portion of the trajectory plan to include;

(i) a steering parameter to be fixed for a first duration of time and (ii) a speed parameter to be fixed for a second duration of time, wherein the first duration of time and the second duration of time are of different lengths;

computing input controls for autonomously controlling the vehicle according to the fixed portion of the trajectory plan; and

controlling the vehicle according to the input controls over the subsequent segment of the roadway.

15. The method of claim 14, wherein the second duration of time for the speed parameter is shorter than the first duration of time for the steering parameter.

16. The method of claim 14, wherein the first duration of time for the steering parameter is shorter than the second duration of time of the speed parameter.

17. The method of claim 14, further comprising:

dynamically selecting lengths of time for the first duration and the second duration according to trajectory data that identifies a present context of the vehicle.

18. The method of claim 17, further comprising:

collecting, from sensors of the vehicle, the trajectory data that identifies a present context according to operating characteristics of the vehicle and environmental characteristics about surroundings of the vehicle.

19. The method of claim 14, wherein the trajectory plan defines a course along the roadway for autonomously controlling the vehicle, wherein the first duration and the second duration are partially coextensive according to an offset between the first duration and the second duration, and wherein the fixed portion of the trajectory plan is unmodifiable once set to maintain consistent operation of the vehicle along the trajectory plan on the roadway.

20. The method of claim 14, wherein updating the trajectory plan includes adjusting target points in the trajectory plan beyond a current segment prior to fixing the first duration and the second duration for the steering parameter and the speed parameter, and

wherein computing the input controls includes computing the input controls from the fixed portion at discrete points in time along the trajectory plan.