Path planning autopilot
View Patent ↗A path planning autopilot guides vehicles efficiently even when they are far from a desired path.
1. A vehicle autopilot comprising:
a microprocessor and memory;
a GNSS receiver that provides vehicle position, velocity and time estimates to the microprocessor;
a feedback controller and a feed-forward controller, the feedback controller generating vehicle curvature commands based on measured heading and y-offset data and a desired path, the feed-forward controller generating vehicle curvature commands based on a calculated joining path from the vehicle position to the desired path; and,
a vehicle steering actuator.
2. The autopilot of claim 1 , the feedback and feed-forward controllers residing in the microprocessor.
3. The autopilot of claim 1 , the joining path not exceeding a maximum allowable curvature θ max .
4. The autopilot of claim 3 , the maximum allowable curvature θ max being estimated from data recorded during vehicle operation.
5. The autopilot of claim 1 , the joining path not exceeding a maximum allowable curvature rate μ.
6. The autopilot of claim 5 , the maximum allowable curvature rate μ being estimated from data recorded during vehicle operation.
7. The autopilot of claim 1 , the desired path being a line.
8. The autopilot of claim 7 , the joining path not exceeding a maximum angle φ max away from the line.
9. The autopilot of claim 1 , the joining path comprising a first optimal turn.
10. The autopilot of claim 9 , the joining path further comprising a line preceding the first optimal turn.
11. The autopilot of claim 9 , the joining path further comprising a second optimal turn following the first optimal turn.
12. The autopilot of claim 9 , the joining path further comprising a line following the first optimal turn and a second optimal turn following the line.
13. The autopilot of claim 9 , the first optimal turn comprising a first clothoid.
14. The autopilot of claim 13 , the first optimal turn further comprising a circular arc preceding the first clothoid.
15. The autopilot of claim 13 , the first optimal turn further comprising a second clothoid following the first clothoid.
16. The autopilot of claim 13 , the first optimal turn further comprising a circular arc following the first clothoid and a second clothoid following the circular arc.
17. The autopilot of claim 1 , the joining path comprising a first turn in a first direction and a second turn in a second direction opposite to the first.