Systems and methods for determining steer while stopped behavior for a vehicle using dynamic limits
This document discloses system, method, and computer program product embodiments for operating a vehicle. For example, the method includes: obtaining a vehicle trajectory and a location of an object in an environment; generating a margin comprising a first vehicle trajectory indicating a series of locations of the vehicle while contacting the object, a boundary of a drivable area or lane mark during a time interval in which the vehicle will travel past the object; generating a reachable boundary using a condition of the vehicle, a longitudinal speed profile and steering limits of the vehicle; comparing the reachable boundary and the margin; and concluding that the vehicle should steer while stopped when the reachable boundary is at any point within a threshold distance from the margin or that the vehicle should not steer while stopped when the reachable boundary is at no point within the threshold distance from the margin.
1. A method for operating a vehicle, comprising:
obtaining, by a processor, a vehicle trajectory for the vehicle and a location of an object in an environment;
generating, by the processor, a margin comprising a first vehicle trajectory indicating a series of locations of the vehicle while contacting the object, a boundary of a drivable area or lane mark during a time interval in which the vehicle will travel past the object;
generating, by the processor, a reachable boundary using a condition of the vehicle, a longitudinal speed profile and steering limits of the vehicle, wherein the reachable boundary comprises a second vehicle trajectory indicating a series of locations of the vehicle while traveling in a forward direction with a certain speed and using full steering limits;
comparing, by the processor, the reachable boundary and the margin;
concluding, by the processor, that the vehicle should steer while stopped when the reachable boundary is at any point within a threshold distance from the margin or that the vehicle should not steer while stopped when the reachable boundary is at no point within the threshold distance from the margin; and
controlling, by the processor, steering of the vehicle when a conclusion is made that the vehicle should steer while stopped.
2. The method according to claim 1 , wherein the generating the margin comprises:
analyzing, by the processor, the vehicle trajectory to identify the time interval in which a footprint of the vehicle overlaps laterally with a footprint of the object;
shifting a location of the footprint of the vehicle laterally within the time interval until contact is made with the footprint of the object; and
defining the first vehicle trajectory by drawing a line through a center of gravity of the vehicle footprint at each laterally shifted location of the footprint of the vehicle.
3. The method according to claim 1 , wherein the generating the margin comprises:
identifying, by the processor, a series of locations of a footprint of the vehicle along the vehicle trajectory within the time interval;
shifting, at each said location, the footprint of the vehicle laterally until contact is made with the boundary of the drivable area or the lane mark; and
defining the first vehicle trajectory by drawing a line through a center of gravity of the vehicle footprint at each laterally shifted location of the footprint of the vehicle.
4. The method according to claim 1 , wherein the condition of the vehicle comprises a position, an orientation and a current wheel angle.
5. The method according to claim 1 , wherein the reachable boundary represents how much to the left or right the vehicle can veer when using the full steering limits given the condition of the vehicle and the longitudinal speed profile.
6. The method according to claim 1 , further comprising:
performing said comparing when the vehicle is within a threshold distance from the object; or
concluding that the vehicle should not steer while stopped when the vehicle is not within the threshold distance from the object.
7. The method according to claim 1 , further comprising:
identifying, by the processor, a free space in the drivable area through which the vehicle can fit when passing the object;
obtaining, by the processor, a width of the free space; and
performing said comparing when the width is greater than a value.
8. The method according to claim 7 , further comprising concluding that the vehicle should not steer while stopped when the width is less than the value.
9. The method according to claim 1 , further comprising:
performing said comparing when the vehicle is not parked; or
concluding that the vehicle should not steer while stopped when the vehicle is parked.
10. The method according to claim 1 , wherein the reachable boundary is compared to the margin the vehicle is not parked.
11. A system, comprising:
a memory; and
at least one processor coupled to the memory and configured to:
obtain a vehicle trajectory for the vehicle and a location of an object in an environment;
generate a margin comprising a first vehicle trajectory indicating a series of locations of the vehicle while contacting the object, a boundary of a drivable area or lane mark during a time interval in which the vehicle will travel past the object;
generate a reachable boundary using a condition of the vehicle, a longitudinal speed profile and steering limits of the vehicle, wherein the reachable boundary comprises a second vehicle trajectory indicating a series of locations of the vehicle while traveling in a forward direction with a certain speed and using full steering limits;
compare the reachable boundary and the margin; and
conclude that the vehicle should steer while stopped when the reachable boundary is at any point within a threshold distance from the margin or that the vehicle should not steer while stopped when the reachable boundary is at no point within the threshold distance from the margin; and
control steering of the vehicle when a conclusion is made that the vehicle should steer while stopped.
12. The system according to claim 11 , wherein the margin is generated by:
analyzing the vehicle trajectory to identify the time interval in which a footprint of the vehicle overlaps laterally with a footprint of the object;
shifting a location of the footprint of the vehicle laterally within the time interval until contact is made with the footprint of the object; and
defining the first vehicle trajectory by drawing a line through a center of gravity of the vehicle footprint at each laterally shifted location of the footprint of the vehicle.
13. The system according to claim 11 , wherein the margin is generated by:
identifying a series of locations of a footprint of the vehicle along the vehicle trajectory within the time interval;
shifting the footprint of the vehicle laterally until contact is made with the boundary of the drivable area or the lane mark; and
defining the first vehicle trajectory by drawing a line through a center of gravity of the vehicle footprint at each laterally shifted location of the footprint of the vehicle.
14. The system according to claim 11 , wherein the condition of the vehicle comprises a position, an orientation and a wheel angle.
15. The system according to claim 11 , wherein the reachable boundary represents how much to the left or right the vehicle can veer when using the full steering limits given the condition of the vehicle and the longitudinal speed profile.
16. The system according to claim 11 , wherein the reachable boundary is compared to the margin when the vehicle is within a threshold distance from the object.
17. The system according to claim 11 , wherein the at least one processor is further configured to:
identify a free space in the drivable area through which the vehicle can fit when passing the object;
obtain a width of the free space; and
compare the reachable boundary to the margin when the width is greater than a value.
18. A non-transitory computer-readable medium that stores instructions that is configured to, when executed by at least one computing device, cause the at least one computing device to perform operations comprising:
obtaining a vehicle trajectory for the vehicle and a location of an object in an environment;
generating a margin comprising a first vehicle trajectory indicating a series of locations of the vehicle while contacting the object, a boundary of a drivable area or lane mark during a time interval in which the vehicle will travel past the object;
generating a reachable boundary using a condition of the vehicle, a longitudinal speed profile and steering limits of the vehicle, wherein the reachable boundary comprises a second vehicle trajectory indicating a series of locations of the vehicle while traveling in a forward direction with a certain speed and using full steering limits;
concluding that the vehicle should steer while stopped when the reachable boundary is at any point within a threshold distance from the margin or that the vehicle should not steer while stopped when the reachable boundary is at no point within the threshold distance from the margin; and
controlling steering of the vehicle when a conclusion is made that the vehicle should steer while stopped.