1. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB, An Improved Line-of- Sight Guidance Law for UAVs R. Curry, M. Lizarraga, B. Mairs, and G.H. Elkaim University of California, Santa Cruz

2. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Accelerating UAV Demand Military Civilian Forestry Marine Fisheries Photography Border surveilance New Missions  New Autopilot Designs

3. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB SLUGS Put in your descriptio n

4. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Line-of-Sight Guidance Originally proposed by Amidi (1991) for robots Park, Deyst, How (2007) made significant contributions Theory Linear Analysis Asymptotic stability Flight demonstrations A form of pursuit guidance originally used in air- to-air missiles

5. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Line-of-Sight Guidance

6. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Acceleration Geometry Kinematics Combined L1 constant UAV Bank angle

7. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Linear Model (Park, Deyst, How)

8. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Linear Model (cont) System Response where Note: wn increases with Vg Let

9. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Linear Model with Roll Dynamics

10. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Root Locus with Roll Dynamics

11. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Summary of Guidance Asymptotically stable assuming instantaneous acceleration response Reduced stability with increasing ground speed not specified in operational situations Errors larger than (track acquisition) If desired track does not exist (go direct)

12. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Guidance Look ahead distance depends on ground speed T* is constant Poles independent of ground speed ALWAYS define an aim point Limit intercept angle (reduce overshoot) Limit down track aim point distance Large errors and track acquisition

13. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Guidance

14. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Simulations 6 DOF nonlinear rigid body model of Rascal UAV Hobby aircraft, wing span of 1.2m Inputs: throttle, elevator, aileron, rudder Outputs: 12 state variables Dryden model wins Constant wind Gust levels depend on height above ground and mean wind

15. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB and on Waypoints

16. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB and Circle Tracking

17. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Homing Mode What if there is a destination but no path? Point ground track from current position to objective Aircraft use “direct to” everyday uses one guidance law in all conditions Automatic “Return To Base” if comm failure

18. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Homing Mode—Return To Base

19. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB Moving “Base” The homing mode only requires a line of sight to the objective There is no requirement that the objective be stationary Useful for tracking moving objectives We used the L2+ homing mode on moving base without any modification

20. UC SANTA CRUZ, AUTONOMOUS SYSTEMS LAB RTB with Moving “Base”