Mission Scenario: Autonomous Cargo Delivery
Objective
Deliver a 2kg medical package to a remote clinic. The landing zone is small and surrounded by trees, requiring a precision winch delivery instead of a landing.
Vehicle Configuration
- Type: Hexacopter (Heavy Lift).
- Payload: Winch system with an electro-magnetic gripper.
- Failsafes: Battery Failsafe set to "Land" (not RTL) due to distance.
Key Concepts
- Precision Placement:
NAV_PAYLOAD_PLACEautomates the descent and touchdown detection, which is safer than manual piloting when depth perception is limited. - Mission Re-Entry: Using
DO_RETURN_PATH_STARTensures that if the drone aborts the delivery, it flies a safe exit vector away from the trees before returning home.
Mission Plan
| Seq | Command | Parameters | Description |
|---|---|---|---|
| 1 | NAV_TAKEOFF |
Alt: 50m | Climb to cruise altitude. |
| 2 | DO_GRIPPER |
Action: Grab | Ensure package is secured (redundancy check). |
| 3 | NAV_WAYPOINT |
Lat/Lon: [Clinic Approach] | Transit to delivery site. |
| 4 | DO_LAND_START |
- | Marker: Begin approach sequence. |
| 5 | DO_WINCH |
Action: Length, Val: 10m | Lower package 10m below drone while still high above trees. |
| 6 | NAV_LOITER_TIME |
Time: 5s | Pause to let the load stabilize (dampen pendulum swing). |
| 7 | NAV_PAYLOAD_PLACE |
Max Descent: 20m | Descend slowly until winch load decreases (touchdown). |
| 8 | DO_GRIPPER |
Action: Release | Drop the package. |
| 9 | DO_WINCH |
Action: Length, Val: 0m | Retract cable immediately to avoid snagging. |
| 10 | NAV_WAYPOINT |
Alt: 50m | Climb vertically back to cruise height. |
| 11 | NAV_RETURN_TO_LAUNCH |
- | Return home. |
Pro-Tips
- Slung Load Stability: Use
LOITER_UNLIMcombined withNAV_SCRIPT_TIMEto run a Lua script that detects load oscillation. Only proceed to the drop once the swing amplitude is < 5 degrees. - Emergency Release: Map a "Emergency Winch Relax" switch on your RC transmitter. If the cable snags on a tree during the climb out, you must instantly unspool the winch to save the aircraft.