The UAV Automaton Phase 02

The second development phase for the UAV Automaton, DLE-JW02-A2 is to integrate FPV and Autopilot system to the model. The FPV system should be included to provide the live aerial feed of the FPV camera which is transmitted to the ground monitoring station. For further FPV setup details, please refer to the related articles section below. Besides providing the aerial video for piloting the model, the flight parameters are transmitted and displayed to the ground monitoring station through the FPV system as the telemetry data called the OSD (On Screen Display). The OSD will overlay the aerial view with various parameters; such as compass / GPS heading, altitude, airspeed, distance from HOME position, travelled distance, current draws, power consumption, battery voltage, etc.

The Autopilot system consists of the Autopilot & OSD system modules and the Radio data link. In this case, the system modules being implemented are from FeiyuTech, however some autopilot modules or flight controllers from other manufacturers might have a similar or close to the system being discussed in this article. Metric unit system is used for the measurement. You should select other manufacturers which will provide the measuring system unit (Metric [ m ] or Imperial [ inch ]) to suit your preference.

The FY-41AP Autopilot and OSD system consists of:

•  FY-41AP module with integrated 3-axis gyro, 3-axis accelerometer, 3-axis magnetometer and a barometric pressure sensor. This will enable the flight modes features such as ABM (Auto Balance mode), ACM (Auto Circle Mode), Fixed Altitude & Heading Lock mode, Waypoint Navigation Mode and RTL/RTH (Return To Launch / Return to Home).  
• Vibration damping pads to mount the module with minimal noise from vibration.
• Airspeed sensor to calculate the flight speed and to control further function like throttle management.
• GPS receiver module to calculate flight course and sense the current location of the model.
• Power manager which consists of the voltage regulator for powering +5V DC for the FY-41AP module and Radio Receiver, +12V DC for the FPV camera and AV Transmitter and receiver, and also has an integrated current sensor to calculate the Battery status ( Voltage [V], Current drained [A] and power drained [ mAh ] ).
• USB data cable for setting up the Autopilot module’s configuration through GCS (Ground Control Station) laptop. It is also used for connecting the radio data link to the GCS laptop.

The FY-602 radio data link consists of:

•  2 units of the Tx/Rx modules; one is to be connected to the FY-41AP module and another is to be connected to the GCS laptop. These Data link modules will transmit and receive to exchange the telemetry data for both displaying the flight data to the GCS and real-time control of the model flight course, flight modes, change of flight plan mission through waypoints.

This radio data link is yet to be tested and discussed at further development phase.

The installation procedure of the Autopilot system starts with the assembly of the vibration damping pads. They provide 2 options; using adhesive foam pads or using the rubber suspended mount pad. The rubber mount pad is better at dampening the vibration which comes from motor, propeller, etc. The vibration noise is to be kept at minimum to achieve the optimum precision in the measuring system and hence a better stabilized flight.

The following procedure is to prepare the electrical connections to be soldered. The power manager module has the power input and output which are to be connected to the battery and the ESC respectively. When implementing FY-41AP, the FPV camera power is supplied from the power manager through the autopilot module (3-pin header) and the camera has to be +12 V DC for its input voltage. Just like the FPV camera, the AV transmitter is powered by the power manager through the autopilot module through the 3-pin header. The 3-pin header has 3-coloured-cables; the yellow / white is for signal line, red is for +V DC line , and the brown / black is for GND / ground (0V) line.

The following diagram shows the connection to the FY-41AP module. Please refer to the autopilot module’s manual from each respective manufacturer for the proper connection details.

The pre-assembled autopilot module should be mounted as close as possible to the C.O.G of the model before proceeding to the tuning and calibration phase. The sensor module, such as the GPS receiver module should be mounted at some considerable distance from the radio receiver antennas and the FPV AV transmitter in order to minimize the noise. The Airspeed sensor probe should be mounted in such a way that the airflow in front of the probe is reading the proper airspeed, not blocked or affected by the propeller’s propwash.

After the electronics wiring and mounting installation, the Autopilot module is to be configured / tuned and calibrated. The USB data cable is used to write and save the config data preset from the GCS laptop to the Autopilot module. This tuning and calibration phase involves several software; the USB data cable driver, the autopilot module setting interface, the GCS software, the Google Earth plugins, etc. The procedures are discussed in detail in the manual from the manufacturers.

Please note that you should choose the Autopilot / flight controller platform which will suit you comfortably regarding the required features, the ease in installation, the ease in using the tuning and calibration software, the ease in upgrading the firmware, and finally the comprehension in using the system. Improper and incomplete assembly, installation, tuning and calibration might cause unexpected damage to the model’s system, even the loss of the entire model. Please use the product responsibly and always consult with the retailers before considering integrating the system to your model.

During the gyro initialization and record altitude procedures, the model has to be kept at still position with the wing’s chord line at normal flight position; in this case, with a small amount of angle of attack (2° - 4°).

The flight test setup is as follows:

Tested Drive system :

• Turnigy G10, 810kv, 375W
• Turnigy Trust 55A SBEC Speed Controller
• Revox 12x6E Prop
• Emax ES08MD Digital, Metal Gear servo
• Zippy 4S-2200mAh (35C)

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

Autopilot system:

• FeiyuTech FY-41AP Autopilot and OSD system

Flight debrief :

• 308 grams of solid lead is attached to the cockpit to simulate the additional weight when a high capacity battery is being used; resulting in 2.2kg of A.U.W.
• Airbrake mixing is implemented to preset the flaps and ailevators positions for hand-launch take-off and landing.
• The drive system is inefficient for long duration flight; the test flight lasted for 4 minutes with 3.9km of flight mileage and consumed 1400 mAh of battery capacity. Max airspeed at 86 km/h and cruise speed of 68 km/h. Take-off max current at 42A and cruise speed current at 26A.
• Test flight altitude at 50m - 60m.
• Larger capacity battery is required for thorough test flight. And it is recommended to change the drive system with better efficiency (motor, prop, ESC and battery combination).
• The ABM (Auto Balance Mode) and ACM (Auto Circle Mode) flight mode operations are not properly tuned due to the losing altitude characteristics. The autopilot modules need further tuning and calibration.
• The RTL ( Return To Launch ) flight mode is yet to be tested.
• The data link with GCS (Ground Control Station) interface is yet to be tested.
• Waypoint navigation for fully-autonomous flight is yet to be tested.

Here is the video of the flight event:

Here are some pictures taken from the belly cam:

Future updates :

• Properly tuned and calibrated flight.

• Using more efficient drive system for long duration flight.

• Implementing the radio Data Link for waypoint navigation autonomous flight using GCS.

D.L. ENGINEERING - The Sky is Home

www.dle-tech.info