US-20260126813-A1 - VEHICLE AND METHOD FOR ESTIMATING AND UPDATING TRAJECTORY BASED ON ERROR DYNAMICS

Abstract

An improved vehicle and method to efficiently compute trajectory dynamics by estimating error between a reference trajectory and state kinematics is described herein. The vehicle is configured to obtain a first expected state at a first time and a second expected state at a second time after the first time based on a reference trajectory and using Hermite polynomial interpolation; linearize dynamics associated with the reference trajectory to obtain a linear model of error dynamics for the vehicle; before the second time, estimate a first error between a state of the vehicle at the second time and an expected state at the second time if a trajectory of the vehicle remains unchanged; update the reference trajectory to account for the first error using the linear model of error dynamics; and cause a guidance system of the vehicle to adjust the trajectory according to commands generated based on the updated trajectory.

Inventors

• Lloyd Strohl

Assignees

• BLUE ORIGIN, LLC

Dates

Publication Date

20260507

Application Date

20241106

Claims (20)

1. 1 . A vehicle comprising: a non-transitory data store storing computer-executable instructions; and a processor in communication with the non-transitory data store, wherein the computer-executable instructions, when executed by the processor, configure the processor to: obtain a first expected state of the vehicle at a first time and a second expected state of the vehicle at a second time after the first time based on a reference trajectory and using Hermite polynomial interpolation; linearize dynamics associated with the reference trajectory to obtain a linear model of error dynamics for the vehicle; before the second time, estimate a first error between a state of the vehicle at the second time and the second expected state of the vehicle at the second time if a trajectory of the vehicle remains unchanged; update the reference trajectory to account for the first error using the linear model of error dynamics; and cause a guidance system of the vehicle to adjust the trajectory of the vehicle according to commands generated based on the updated trajectory.
2. 2 . The vehicle of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to cause the guidance system of the vehicle to adjust the trajectory of the vehicle at the second time according to commands generated based on the updated trajectory, wherein the trajectory is adjusted to have a position of the vehicle match the reference trajectory at a third time.
3. 3 . The vehicle of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to cause the vehicle to adjust the trajectory according to the updated trajectory for ascent operations, changing orbits, or descent operations of the vehicle.
4. 4 . The vehicle of claim 1 , wherein the first expected state and the second expected state comprises desired position, velocity, thrust, and mass over time.
5. 5 . The vehicle of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to, before the second time, estimate the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time according to computing kinematic dynamics of the vehicle between the first time and the second time.
6. 6 . The vehicle of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to update the reference trajectory to account for the first error using the linear model of error dynamics without recomputing full nonlinear dynamics of the trajectory.
7. 7 . The vehicle of claim 1 , wherein the computer-executable instructions, when executed by the processor, further cause the processor to: perform interpolation of the first expected state and the second expected state to determine a third expected state of the vehicle at a third time that is between the first time and the second time; before the third time, estimate a second error between a state of the vehicle at the third time and the third expected state if the trajectory of the vehicle remains unchanged; update the reference trajectory to account for the second error using the linear model of error dynamics; and cause the guidance system of the vehicle to adjust the trajectory of the vehicle by the third time according to commands generated based on the updated trajectory.
8. 8 . A computer-implemented method comprising: obtaining a first expected state of a vehicle at a first time and a second expected state of the vehicle at a second time after the first time based on a reference trajectory and using Hermite polynomial interpolation; linearizing dynamics associated with the reference trajectory to obtain a linear model of error dynamics for the vehicle; before the second time, estimating a first error between a state of the vehicle at the second time and the second expected state of the vehicle at the second time; updating the reference trajectory to account for the first error using the linear model of error dynamics; and causing a guidance system of the vehicle to adjust a trajectory of the vehicle according to commands generated based on the updated trajectory.
9. 9 . The method of claim 8 , wherein causing the guidance system of the vehicle to adjust the trajectory of the vehicle according to commands generated based on the updated trajectory further comprises causing the guidance system of the vehicle to adjust the trajectory of the vehicle at the second time according to commands generated based on the updated trajectory, wherein the trajectory is adjusted to have a position of the vehicle match the reference trajectory at a third time.
10. 10 . The method of claim 8 , wherein causing the guidance system of the vehicle to adjust the trajectory of the vehicle according to commands generated based on the updated trajectory further comprises causing the vehicle to adjust the trajectory of the vehicle according to commands generated based on the updated trajectory for ascent operations, changing orbits, or descent operations of the vehicle.
11. 11 . The method of claim 8 , wherein before the second time, estimating the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time further comprises, before the second time, estimating the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time according to computing kinematic dynamics of the vehicle between the first time and the second time.
12. 12 . The method of claim 8 , wherein updating the reference trajectory to account for the first error using the linear model of error dynamics further comprises updating the reference trajectory to account for the first error using the linear model of error dynamics without recomputing full nonlinear dynamics of the trajectory.
13. 13 . The method of claim 8 , wherein before the second time, estimating the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time further comprises, before the second time, estimating the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time if a trajectory of the vehicle remains unchanged.
14. 14 . The method of claim 8 , further comprising: performing interpolation of the first expected state and the second expected state to determine a third expected state of the vehicle at a third time that is between the first time and the second time; before the third time, estimating a second error between a state of the vehicle at the third time and the third expected state if the trajectory of the vehicle remains unchanged; updating the reference trajectory to account for the second error using the linear model of error dynamics; and causing the guidance system of the vehicle to adjust the trajectory of the vehicle by the third time according to commands generated based on the updated trajectory.
15. 15 . Non-transitory, computer-readable storage media comprising computer-executable instructions for computing linearized dynamics of a vehicle, wherein the computer-executable instructions, when executed by a computer system onboard the vehicle, cause the computer system to: obtain a first expected state of the vehicle at a first time and a second expected state of the vehicle at a second time after the first time based on a reference trajectory and using Hermite polynomial interpolation; linearize dynamics associated with the reference trajectory to obtain a linear model of error dynamics for the vehicle; before the second time, estimate a first error between a state of the vehicle at the second time and the second expected state of the vehicle at the second time if a trajectory of the vehicle remains unchanged; update the reference trajectory to account for the first error using the linear model of error dynamics; and cause a guidance system of the vehicle to adjust a trajectory of the vehicle according to commands generated based on the updated trajectory.
16. 16 . The non-transitory, computer-readable storage media of claim 15 , wherein the computer-executable instructions further cause the computer system to cause the guidance system of the vehicle to adjust the trajectory of the vehicle at the second time according to commands generated based on the updated trajectory, wherein the trajectory is adjusted to have a position of the vehicle match the reference trajectory at a third time.
17. 17 . The non-transitory, computer-readable storage media of claim 15 , wherein the computer-executable instructions further cause the computer system to cause the vehicle to adjust the trajectory according to the updated trajectory for ascent operations, changing orbits, or descent operations of the vehicle.
18. 18 . The non-transitory, computer-readable storage media of claim 15 , wherein the computer-executable instructions further cause the computer system to, before the second time, estimate the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time according to computing kinematic dynamics of the vehicle between the first time and the second time.
19. 19 . The non-transitory, computer-readable storage media of claim 15 , wherein the computer-executable instructions further cause the computer system to update the reference trajectory to account for the first error using the linear model of error dynamics without recomputing full nonlinear dynamics of the trajectory.
20. 20 . The non-transitory, computer-readable storage media of claim 15 , wherein the computer-executable instructions further cause the computer system to: perform interpolation of the first expected state and the second expected state to determine a third expected state of the vehicle at a third time that is between the first time and the second time; before the third time, estimate a second error between a state of the vehicle at the third time and the third expected state if the trajectory of the vehicle remains unchanged; update the reference trajectory to account for the second error using the linear model of error dynamics; and cause the guidance system of the vehicle to adjust the trajectory of the vehicle by the third time according to commands generated based on the updated trajectory.

Description

TECHNICAL FIELD The present disclosure generally relates to optimizing trajectories of vehicles. BACKGROUND Vehicles that operate in space may have capabilities to land on a surface of a target destination. The vehicles may be able to determine a trajectory for landing by using a combination of onboard sensors and pre-programmed algorithms. The vehicles may follow a predetermined trajectory based on mission planning and simulations. As the vehicles approach a designated landing site, the vehicles may follow the trajectory for landing at the designated landing site. SUMMARY OF THE INVENTION The systems, methods, and devices described herein each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure, several non-limiting features will now be discussed briefly. One aspect of the disclosure provides a vehicle. The vehicle comprises a non-transitory data store storing computer-executable instructions. The vehicle further comprises a processor in communication with the non-transitory data store, wherein the computer-executable instructions, when executed by the processor, configure the processor to: obtain a first expected state of the vehicle at a first time and a second expected state of the vehicle at a second time after the first time based on a reference trajectory and using Hermite polynomial interpolation; linearize dynamics associated with the reference trajectory to obtain a linear model of error dynamics for the vehicle; before the second time, estimate a first error between a state of the vehicle at the second time and the second expected state of the vehicle at the second time if a trajectory of the vehicle remains unchanged; update the reference trajectory to account for the first error using the linear model of error dynamics; and cause a guidance system of the vehicle to adjust the trajectory of the vehicle according to commands generated based on the updated trajectory. The vehicle of the preceding paragraph can include any sub-combination of the following features: where the computer-executable instructions, when executed by the processor, further cause the processor to cause the guidance system of the vehicle to adjust the trajectory of the vehicle at the second time according to commands generated based on the updated trajectory, where the trajectory is adjusted to have a position of the vehicle match the reference trajectory at a third time; where the computer-executable instructions, when executed by the processor, further cause the processor to cause the vehicle to adjust the trajectory according to the updated trajectory for ascent operations, changing orbits, or descent operations of the vehicle; where the first expected state and the second expected state comprises desired position, velocity, thrust, and mass over time; where the computer-executable instructions, when executed by the processor, further cause the processor to, before the second time, estimate the first error between the state of the vehicle at the second time and the second expected state of the vehicle at the second time according to computing kinematic dynamics of the vehicle between the first time and the second time; where the computer-executable instructions, when executed by the processor, further cause the processor to update the reference trajectory to account for the first error using the linear model of error dynamics without recomputing full nonlinear dynamics of the trajectory; where the computer-executable instructions, when executed by the processor, further cause the processor to: perform interpolation of the first expected state and the second expected state to determine a third expected state of the vehicle at a third time that is between the first time and the second time, before the third time, estimate a second error between a state of the vehicle at the third time and the third expected state if the trajectory of the vehicle remains unchanged, update the reference trajectory to account for the second error using the linear model of error dynamics, and cause the guidance system of the vehicle to adjust the trajectory of the vehicle by the third time according to commands generated based on the updated trajectory; Another aspect of the disclosure provides computer-implemented method comprising the steps of obtaining a first expected state of a vehicle at a first time and a second expected state of the vehicle at a second time after the first time based on a reference trajectory and using Hermite polynomial interpolation; linearizing dynamics associated with the reference trajectory to obtain a linear model of error dynamics for the vehicle; before the second time, estimating a first error between a state of the vehicle at the second time and the second expected state of the vehicle at the second time; updating the reference trajectory to account for the first error using the linear model of error dynamics; and causin