The UAV automaton Phase 03

This is a brief update on the third development phase of the UAV Automaton, DLE-JW02-A2. On the previous development phase, the Autopilot functions are not yet thoroughly tested due to the short flight duration. The phase 03 of the development involves testing a new propulsion system setup which is expected to provide better efficiency for long duration flight and also to further test the autopilot functions.

It is decided to change the propulsion system to have better flight efficiency.

The specification is as follows:

New Setup :

• Brushless motor : Emax BL 2815/09, 920kv
• ESC : Emax 60A
• Propeller : Revox 9x6E
• Revox Nanotech 4S-5500mAh (30C)

Previous Setup :

• Brushless motor : Turnigy G10, 810kv, 375W
• ESC : Turnigy Trust 55A SBEC
• Propeller : Revox 12x6E
• Li-po Batt : Zippy compact 4S-2200mAh (35C)

Radio Tx/Rx system :

• Futaba T8FG Super, 2.4 GHz transmitter
• Futaba R6028SB, 8ch 2.4 GHz receiver

FPV system :

• FPV cam : 1/3 " Sony CCD camera, 700VTL
• Belly cam: GoPro Hero 3 Black Edition camera
• Aomway AV Transmitter, 5.8GHz, 1000mW, clover-leaf antenna
• Aomway AV Receiver, 5.8GHz, built-in DVR, clover-leaf antenna
• Feelworld 7 Inch FPV ground monitor

Flight Controller :

• FeiyuTech FY-41AP Autopilot and OSD system

50 grams of solid lead is attached to the cockpit as a counter weight to achieve the proper C.O.G; resulting in 2.2kg of A.U.W. The new propulsion setup produces less thrust than the previous setup and to hand launch the Automaton, running a couple of meters into the headwind allows easy take-off. To further ease the take-off procedure, Airbrake mixing is implemented to preset the flaps and ailevators positions during the take-off.

The tested autopilot functions are ABM (Auto Balance Mode), ACM (Auto Circle Mode) and RTL (Return To Launch). The ABM flight mode operations is still not properly tuned due to the rolling right and losing altitude characteristics. The autopilot modules need further tuning; probably the gain setting and/or PID parameter for turn control. The ACM flight mode functioned normally and turns slowly, or even travel in straight line when turning against the wind. The slow and loose turn might also caused by a large setting of circle radius (100 m). While the ACM is activated, throttle is managed by the autopilot; maintaining the cruise speed by reading from ASI (Airspeed Speed Indicator). The RTL flight mode also functioned as expected and the auto-throttle management is also activated in this flight mode. There was an unplanned RC fail-safe test due to the model was flying behind the pilot and behind the pilot there were tall trees blocking the RC signal transmission. The RC fail-safe has been preset to activate the RTL switch and hold the throttle at 60%. However, during that RTL, the throttle deviated from 60% and believed it was controlled by the auto-throttle management. The RTL flight mode was deactivated as soon as the RC signal got reconnected.

Here is the Flight summary :

• Total Flight Mileage  : 11 km
• Total Flight Time      : 15 minutes
• Battery Consumed   : 4000 mAh
• Max Airspeed          : 79 km/h
• Cruise Airspeed       : 64 km/h
• Take-off current        : 42 A (should be more because of the bugs in the old firmware version)
• Cruise current          : 15 A
• Flight Test Altitude   :  48 m – 122 m

After the flight, the Li-Po batt was at approximately 14.83 V, 58% (read from cell meter; expect some difference and tolerances from the actual). The flight endurance should be tested until the Li-Po batt reached the low-level voltage / cut-off voltage in order to obtain the maximum capable flight time for this current setup.

Here is the video of the event:

Future updates :

• Further tuning of ABM until it reached the normal / expected function.

• Implementing the data link with GCS (Ground Control Station) interface.

• Implementing Waypoint navigation for fully-autonomous flight.

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