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Building Fixed Wing UAV for Aerial Mapping

Posted by Pragadish Santhosh on June 26, 2018 at 4:34am

Am looking for building a Fixed Wing UAV for Aerial mapping and performing it based on my own research. Your suggestions are most welcome to correct myself in building it. 

AIM

To assemble a Fixed wing UAV for Aerial Mapping with 2.5 - 3 hours endurance

REQUIRED PARTS

1. Skywalker X8 (2122mm) airframe

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2. TURNIGY Plush 60amp Electronic Speed Controller

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3. Aeronaut CAM carbon 12x6.5 folding prop blades, Aeronaut 36mm Precision Spinner for 5mm shafts, 38mm Aluminium centre piece, Folding Propeller Blade Stopper

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4. X8R 8/16Ch - FrSky S.BUS ACCST Telemetry Receiver

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5. Digital Air Speed Sensor And Pitot Tube Set

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6. Turnigy TGY-225MG Analog High Torque Servo 26g – 2

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7. Turnigy Aerodrive SK3 - 3542-800kv motor

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8. Pixhawk 2.1 autopilot

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9. Taranis X9D Plus transmitter

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10. HERE GPS

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11. 22,050 mAh Li- ion battery – 2

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13. Carbon Fiber sheet (1 Roll – 4 x 6)

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14. Balsa Wood 

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Tags: drone, fixed, mapping, survey, uav, wing
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Replies

  • VenomFPV November 18, 2019 at 4:55pm

    Hello... excellent build, i am a late joiner, building my 1st Skywalker X8, have bought most of the needed components, abou some stuff i am confused.

    what size carbon fiber rods should i get to reinforce the wings, will 1mm be sufficient enough or 1.5mm

    and what is the thickness of the carbon fiber sheet youre using, i dont want to accidently order a really thick one.

    and can you kindly post a wiring diagram i am having issues, i am also using the same Pixhawk 2.1

    thanks, will wait for your reply

  • hank grimes August 3, 2018 at 8:28pm

    Are you using pre-preg carbon fibre sheets that just need to be ironed on?

    also how have you mitigated / what issues if any have you encountered with RF attenuation due to the carbon fibre shielding film?

  • Pragadish Santhosh August 3, 2018 at 3:29am

                                                                             TEST FLIGHT - 3

    Description:

    1. Pre Flight Checklist checks done.
    2. Flight checked for FBWA mode and its performance to the same.
    3. Take Off done at FBWA mode by Hand Launch. (Refer to Video)https://www.youtube.com/watch?v=qTBVINGVOGA
    4. Take Off time noted. Followed by that performance monitored in Mission Planner HUD Display. Take Off done perfectly
    5. After take-off, within a second sudden hard landing happened.
    6. At the time of crash only we found that the flight mode was set manual (some mistake happened during handling of Transmitter). Because of that, flight not able to stabilize during take-off.
    7. We recovered the flight parts and made repair. Then set ready for the next flight.
    8. This time after hand launch, flight didn’t respond to the throttle control for take-off because of that immediate hard landing happened.
    9. This time damage was more when compared to test flight 2(2).
    10. During crash, damages are
    • Fuselage Nose part material broken because of battery weight during landing.
    • Propeller Blades broken
    • Wing Spar (Carbon fiber tube) Long one broken.
    • Elevon Horn came out from elevon also push rod fitted to that elevon also had bent.
    • Wings bottom attachment part came out. (even it was attached to the wings using

    Z-poxy)

    Analysis- Test Flight 3 (1):

    1. Log Data Downloaded from Autopilot
    2. Log File Loaded into Mission Planner
    3. In the Flight log graph message area it is confirmed that in “manual mode” take off done.3702438749?profile=original
    4. In the message area below the graph except EKF message there are no other indications.
    5. And before take-off, while checking CG we compromised some imbalance. May be because of that, the flight was not stable and also the flight mode was manual at that time which didn’t allow flight to get stabilize on its own.3702438636?profile=original

    Analysis- Test Flight 3 (2):3702438921?profile=original

    1. In this log it is found that there is a sudden drop of throttle input and output after few seconds of take-off.
    2. In the message area below the graph also there is no error message. Only throttle armed and disarmed messages found.
    3. So the reason for hard landing might be same as previous flight.

     

  • Pragadish Santhosh August 3, 2018 at 2:37am

                                                                                   TEST FLIGHT - 2

    Description:

    1. Pre Flight Checklist checks done.
    2. Flight checked for FBWA mode and its performance to the same.
    3. Take Off done at FBWA mode by Hand Launch. (Refer to Video)https://www.youtube.com/watch?v=NtB0Jt04YHU
    4. Take Off time noted. Followed by that performance monitored in Mission Planner HUD Display.
    5. Take Off done perfectly. After Take – Off for more than 1 minutes there was no problem with the flight. But suddenly an “EKF Variance “alert message displayed in the “HUD Display” of Mission planner. Even though the flight was in full control.
    6. With the alert message we decided to land the flight using Landing net.
    7. For Landing, Throttle % was fully dropped down but still the speed was not less enough to land in net. Due to its more speed the airframe was damaged slightly especially wings leading edges and bottom surfaces.
    8. Then throttle disarm done.
    9. We did required airframe repairs and set the flight for next test. At this time, we decided to disable one of the compass because of compass variance issue during previous flight test. (It is not recommended to do).
    10. Second take off done perfectly. Then followed the control as well. Within few minutes flight itself suddenly descends and had crash landing.
    11. During crash, damages are
    • HERE GPS module came out from its position
    • Propeller Blades broken
    • Wing Spar (Carbon fiber tube) Long one broken.
    • Elevon Horn came out from elevon also push rod fitted to that elevon also had bent.
    • Wings bottom attachment part came out. (even it was attached to the wings using

    Z-poxy)

    Analysis- Test Flight 2 (1):

    1. Log Data Downloaded from Autopilot
    2. Log File Loaded into Mission Planner
    3. By the alert message displayed in the HUD Display, We checked the message in the log at the bottom of the graph.3702439469?profile=original
    4. GPS Status – Red line, RCIN CH3- Green line, RCOUT CH3- Blue Line.
    5. The above mentioned parameters have been selected on the basis of alert message whether it reflected in flight control or autopilot has entered in to any failsafe or not.
    6. But it is noticed no control was lost or mismatch between RCIN and RCOUT not happened. Only alert for variance between Compass inbuilt Pixhawk and external Compass. In order to correct “EKF Variance” required settings had to be done.

    Analysis- Test Flight 2 (2):

    1. During this test flight responds was good also because we disabled one of the compass there was no EKF Variance alert and no any other alerts on HUD display.
    2. Even the flight got hard landing also damage was there as mentioned above.
    3. So to analyse we just selected RCIN and RCOUT of CH3. But in that also no variation.3702439367?profile=original
    4. RCIN CH 3 – Green Line, RCOUT CH3 – Blue Line, Power Issue - orange
    5. The doubt because of sudden descend and hard nose landing falls on power supply from battery. So we selected to graph “Power Issue” option from the drop down list below the graph area.
    6. After Zooming the power issue graph, we found the power has dropped at the point where the descend happened in the flight path.3702439320?profile=original
    7. This drop of Power might happened because of damage during previous hard landing. Then we checked the battery connectors. It is found that Y- Cable connectors used for connecting both the battery pack was bent and because of that it is in loose contact.
  • Pragadish Santhosh July 28, 2018 at 5:44am

                                                                            TEST FLIGHT -1

    Description:

    1. Pre Flight Checklist checks done.
    2. Flight checked for FBWA mode and its performance to the same.
    3. Take Off done at FBWA mode by Hand Launch. (Refer to Video)
    4. Take Off time noted. Followed by that performance monitored in Mission Planner HUD Display.
    5. Take Off done perfectly. In few seconds, No RC Receiver Signal message appeared in the HUD Display.
    6. So for safety, through Actions option in Mission planner Loiter mode selected.
    7. By the time because No RC Receiver signal Autopilot entered in Throttle failsafe short event.
    8. Flight completed 2 circle then entered into Throttle failsafe Long evente RTL mode.
    9. Even in RTL mode flight had crash landing.
    10. During crash, damages are
    • HERE GPS module came out from its position
    • Propeller Blades broken
    • Wing Spar (Carbon fiber tube) Long one broken.
    • Elevon Horn came out from elevon also push rod fitted to that elevon also had bent.

     

    Analysis:

    Downloading Log Data from Auopilot

    1. Flight Data Log from Autopilot downloaded by connecting autopilot to Mission Planner.3702438015?profile=original 2.After connecting Autopilot to mission planner, In the Flight data screen - Dataflash Logs Tab clicked

                3.Under the tab, Download Dataflash Log Via Mavlink option selected. It opens a dialog box which                          shows list of  logs save in autopilot based on date and time.

                4.From the list required log selected by checking check box and Download Selected Log option                              selected.Log Downloading indicated by green bar rising at the bottom of the dialog box.

                 5.Finally download will be completed. Log files will be saved to the computer.

    Loading Log File into Mission Planner

      1. Open Mission Planner, In the Flight Data Screen- Dataflash Logs Tab clicked. Then Select Review a Log3702438036?profile=original
      2. It shows files saved in Mission Planner log Folder, from the list, a file named (DF Log file type) with required date selected.3702438051?profile=original
      3. It opens a window which helps us to read the data in different required aspects, as in below figure.3702438122?profile=original
      4. From the list of Parameters at the right side of this window, required parameter selected to analyse the graph. Also show map check box if enabled it will display trajectory of the flight.
      5. By the information from HUD Display No RC Receiver Signal, the Parameter RCIN CH 3 and RCOUT CH3 selected to analyse.3702438100?profile=original
      6. Red line indicates RCIN CH3 and the Green line indicates RCOUT CH3, from the graph it is found that both RCIN and RCOUT are almost same but when there was No Receiver signal (Circled in the graph). RCIN CH3 PWM value dropped to Zero.
      7. And the RCOUT CH3 PWM Value maintained by autopilot because of Throttle Failsafe condition.3702438143?profile=original3702438214?profile=original8.Through analysis, it is found that due to Receiver signal, Throttle failsafe condition taken place at first short event and after few second long event. Because of this RTL mode enabled and Autopilot decided to land. But on its way to land at launch position it suddenly crashed.
  • Pragadish Santhosh July 28, 2018 at 5:33am

    Hi Rodrigo,

    We chose X8 cuz of the performance it will give in terms of speed and flight time, also the spacious fuselage is one of the reason as we can experiment with more components/payloads.

    We get the telemetry data in our Ground station during flights. You can find more information on Pixhawk 2.0 in ardupilot page. There isn't much information available for pixhawk 2.1. We haven't finalized the selection of RTK and its accessories, so it will take some time to conclude on the RTK. But, yes we plan to use RTK for survey accuracy. We have Here+RTK, Piksi Multi and Emlid Reach as options. Pix4D accepts the log file from AutoPilot/GPS during the processing. You can refer Pix4D documentation website for more information. 

    Stay tuned!



    Rodrigo Valdelomar said:

    Hi Pragadish, 

    Adding RTK sounds awesome. I plan to use it for crop surveying so RTK it's not my main goal but it might be helpful. I'm actually planning to add solar panels to be able to have way longer flights.

    Anyway I'm a rookie so i have a lot of research to through.

    Would you mind explaining a few of your set up choices? I really want to learn more in order to apply it to my experience.

    • Why did you choose a X8 wing? So far I'm thinking about going with a E-flite opterra 2M. I've watch a lots of videos and it seems very effective in soaring mode and it seems to be very hard to get it to stall.
    • X8R 8/16Ch - FrSky S.BUS ACCST Telemetry Receiver. Does this devices reports the Telemetry back to the radio? Can you see the telemetry on a computer and control it somehow?
    • Pixhawk 2.1 autopilot. I still don't undertand how the Pixhawk autopilot works do you have any source of information so i can learn about it?
    • Here GPS. Is this the GPS that you are going to use for RTK? How does it works. Besides that, how are you going to transfer the GPS coordinates to the camera to then be able to stitch it in Pix4D or any other software.

    I know those are a lot of questions but i would really appreciat it if you could help me out.

    Thanks a lot!

    Building Fixed Wing UAV for Aerial Mapping
    Am looking for building a Fixed Wing UAV for Aerial mapping and performing it based on my own research. Your suggestions are most welcome to correct…
  • Rodrigo Valdelomar July 26, 2018 at 8:05am

    Hi Pragadish, 

    Adding RTK sounds awesome. I plan to use it for crop surveying so RTK it's not my main goal but it might be helpful. I'm actually planning to add solar panels to be able to have way longer flights.

    Anyway I'm a rookie so i have a lot of research to through.

    Would you mind explaining a few of your set up choices? I really want to learn more in order to apply it to my experience.

    • Why did you choose a X8 wing? So far I'm thinking about going with a E-flite opterra 2M. I've watch a lots of videos and it seems very effective in soaring mode and it seems to be very hard to get it to stall.
    • X8R 8/16Ch - FrSky S.BUS ACCST Telemetry Receiver. Does this devices reports the Telemetry back to the radio? Can you see the telemetry on a computer and control it somehow?
    • Pixhawk 2.1 autopilot. I still don't undertand how the Pixhawk autopilot works do you have any source of information so i can learn about it?
    • Here GPS. Is this the GPS that you are going to use for RTK? How does it works. Besides that, how are you going to transfer the GPS coordinates to the camera to then be able to stitch it in Pix4D or any other software.

    I know those are a lot of questions but i would really appreciat it if you could help me out.

    Thanks a lot!

  • Pragadish Santhosh July 26, 2018 at 4:37am

    Hi Rodrigo,

    Actually the purpose of going for custom built drone is to improve the accuracy of the results by adding RTK/PPK GPS in future and also to increase the flight time for more area coverage.

    Keep following my posts and do recommend me on improvements.

    Thanks



    Rodrigo Valdelomar said:

    Hi Pragadish Santhosh I'm reading all of this from Argentina.

    I find it really interesting since i have the same idea as to build a fixed wing for mapping. I'll keep on reading as you go forward with the project. 

    I have a few questions, why did you decide to go with that custom set up instead of using something like the CHUCK from a parrot disco? I'm quite new at these and i couldn't find anywhere why Pixhawk set up is better than using something already integrated.

    Thanks and best of luck

    Building Fixed Wing UAV for Aerial Mapping
    Am looking for building a Fixed Wing UAV for Aerial mapping and performing it based on my own research. Your suggestions are most welcome to correct…
  • Rodrigo Valdelomar July 25, 2018 at 6:21pm

    Hi Pragadish Santhosh I'm reading all of this from Argentina.

    I find it really interesting since i have the same idea as to build a fixed wing for mapping. I'll keep on reading as you go forward with the project. 

    I have a few questions, why did you decide to go with that custom set up instead of using something like the CHUCK from a parrot disco? I'm quite new at these and i couldn't find anywhere why Pixhawk set up is better than using something already integrated.

    Thanks and best of luck

    Pragadish Santhosh's Discussions
    Pragadish Santhosh's Discussions | The largest amateur Unmanned Aerial Vehicle (UAV) community. Quadcopters, robot planes and more!
  • Pragadish Santhosh July 25, 2018 at 5:37am

            15) Problem With Airspeed Sensor 

    1. Again same GPS issue occurred. This time we checked with the components connected to Autopilot.
    2. If Airspeed sensor is connected to the circuit GPS is not powering. If Airspeed Sensor is removed from connection GPS Worked properly.
    3. So we Removed the Airspeed sensor from the connection.

         16) ELEVON Plane Settings

    1. Parameters mentioned below need to be setup.3702437597?profile=original

    3702437605?profile=original

    3702437630?profile=original

    3702437246?profile=original

    3702437495?profile=original

    2.Mixing Gain

    The MIXING_GAIN parameter is critical for elevon aircraft. It is the gain used in mixing between roll and pitch output and your elevon movement. For example, if your MIXING_GAIN is 0.5, then the following outputs are used:

    • LEFT_ELEVON = (roll + pitch)*0.5
    • RIGHT_ELEVON = (roll - pitch)*0.5

    3702437752?profile=original

            By adjusting the MIXING_GAIN you can quickly setup the right throws of your elevon aircraft.

     

           18) FBWA mode Check

    1. Flight checked for FBWA mode response.
    2. For this some parameters need to be fixed
    3. Correct FBWA (automatic stabilization)movement for an elevon plane WITHOUT PROVIDING RC INPUT is

    Input

    Action

    Roll right

    Left elevon goes up and right elevon goes down

    Roll left

    Right elevon goes up and left elevon goes down

    Pitch down

    Both elevons go up

    Pitch up

    Both elevons go down

    • If your movements are incorrect then you need to adjust which servo output is left/right and the reversals of each elevon.
    • The parameters you should adjust are SERVO1_REVERSED, SERVO2_REVERSED, SERVO1_FUNCTION and SERVO2_FUNCTION.
    • If your left elevon on servo 1 is moving the wrong way for both pitch and roll corrections, set SERVO1_REVERSED to 1.
    • If your left elevon on servo 1 responds correctly to pitch, but incorrectly to roll, change the SERVO1_FUNCTION.
      1. Repeat the servo reversal or function change for the right elevon.

                

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